WorldWideScience

Sample records for eccentricity

  1. 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...

  2. Inferring the eccentricity distribution

    CERN Document Server

    Hogg, David W; Bovy, Jo

    2010-01-01

    Standard maximum-likelihood estimators for binary-star and exoplanet eccentricities are biased high, in the sense that the estimated eccentricity tends to be larger than the true eccentricity. As with most non-trivial observables, a simple histogram of estimated eccentricities is not a good estimate of the true eccentricity distribution. Here we develop and test a hierarchical probabilistic method for performing the relevant meta-analysis, that is, inferring the true eccentricity distribution, taking as input the likelihood functions for the individual-star eccentricities, or samplings of the posterior probability distributions for the eccentricities (under a given, uninformative prior). The method is a simple implementation of a hierarchical Bayesian model; it can also be seen as a kind of heteroscedastic deconvolution. It can be applied to any quantity measured with finite precision--other orbital parameters, or indeed any astronomical measurements of any kind, including magnitudes, parallaxes, or photometr...

  3. Eccentric connectivity index

    CERN Document Server

    Ilić, Aleksandar

    2011-01-01

    The eccentric connectivity index $\\xi^c$ is a novel distance--based molecular structure descriptor that was recently used for mathematical modeling of biological activities of diverse nature. It is defined as $\\xi^c (G) = \\sum_{v \\in V (G)} deg (v) \\cdot \\epsilon (v)$\\,, where $deg (v)$ and $\\epsilon (v)$ denote the vertex degree and eccentricity of $v$\\,, respectively. We survey some mathematical properties of this index and furthermore support the use of eccentric connectivity index as topological structure descriptor. We present the extremal trees and unicyclic graphs with maximum and minimum eccentric connectivity index subject to the certain graph constraints. Sharp lower and asymptotic upper bound for all graphs are given and various connections with other important graph invariants are established. In addition, we present explicit formulae for the values of eccentric connectivity index for several families of composite graphs and designed a linear algorithm for calculating the eccentric connectivity in...

  4. On eccentric connectivity index

    CERN Document Server

    Zhou, Bo

    2010-01-01

    The eccentric connectivity index, proposed by Sharma, Goswami and Madan, has been employed successfully for the development of numerous mathematical models for the prediction of biological activities of diverse nature. We now report mathematical properties of the eccentric connectivity index. We establish various lower and upper bounds for the eccentric connectivity index in terms of other graph invariants including the number of vertices, the number of edges, the degree distance and the first Zagreb index. We determine the n-vertex trees of diameter with the minimum eccentric connectivity index, and the n-vertex trees of pendent vertices, with the maximum eccentric connectivity index. We also determine the n-vertex trees with respectively the minimum, second-minimum and third-minimum, and the maximum, second-maximum and third-maximum eccentric connectivity indices for

  5. 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…

  6. Oscillations of Eccentric Pulsons

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Groenbech-Jensen, Niels; Lomdahl, Peter;

    1997-01-01

    Perturbation theory for elliptic pulsons is developed and predicts pulson and eccentricity oscillations. The pulson oscillation period is predicted qualitatively correct.......Perturbation theory for elliptic pulsons is developed and predicts pulson and eccentricity oscillations. The pulson oscillation period is predicted qualitatively correct....

  7. Eccentricity from transit photometry

    DEFF Research Database (Denmark)

    Van Eylen, Vincent; Albrecht, Simon

    2015-01-01

    Solar system planets move on almost circular orbits. In strong contrast, many massive gas giant exoplanets travel on highly elliptical orbits, whereas the shape of the orbits of smaller, more terrestrial, exoplanets remained largely elusive. Knowing the eccentricity distribution in systems of small...... 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....

  8. Origin of Prometheus Eccentricity

    Science.gov (United States)

    Rappaport, N. J.; Longaretti, P.

    2006-12-01

    A number of Saturn's small satellites, from Atlas to the coorbital satellites Janus and Epimetheus, move on orbits just outside the main rings of the planet. These satellites undergo extremely rapid resonant interaction with the rings and outward motion, strongly suggesting that they originated in Saturn's A ring. However, their eccentricities, of the order of 1/1000 are several orders of magnitude larger than what could be expected if the small satellites formed in the ring. This paper represents a first step to providing an explanation for this phenomenon, by focusing on the dynamical processes that have affected the eccentricity of Prometheus. The explanation invokes past resonances with the coorbital satellites combined with chaos due to overlapping of these resonances.

  9. Eccentric exercise testing and training

    Science.gov (United States)

    Clarkson, Priscilla M.

    1994-01-01

    Some researchers and practitioners have touted the benefits of including eccentric exercise in strength training programs. However, others have challenged its use because they believe that eccentric actions are dangerous and lead to injuries. Much of the controversy may be based on a lack of understanding of the physiology of eccentric actions. This review will present data concerning eccentric exercise in strength training, the physiological characteristics of eccentric exercise, and the possible stimulus for strength development. Also a discussion of strength needs for extended exposure to microgravity will be presented. Not only is the use of eccentric exercise controversial, but the name itself is fraught with problems. The correct pronunciation is with a hard 'c' so that the word sounds like ekscentric. The confusion in pronunciation may have been prevented if the spelling that Asmussen used in 1953, excentric, had been adopted. Another problem concerns the expressions used to describe eccentric exercise. Commonly used expressions are negatives, eccentric contractions, lengthening contractions, resisted muscle lengthenings, muscle lengthening actions, and eccentric actions. Some of these terms are cumbersome (i.e., resisted muscle lengthenings), one is slang (negatives), and another is an oxymoron (lengthening contractions). Only eccentric action is appropriate and adoption of this term has been recommended by Cavanagh. Despite the controversy that surrounds eccentric exercise, it is important to note that these types of actions play an integral role in normal daily activities. Eccentric actions are used during most forms of movement, for example, in walking when the foot touches the ground and the center of mass is decelerated and in lowering objects, such as placing a bag of groceries in the car.

  10. Eccentric Binary Millisecond Pulsars

    CERN Document Server

    Freire, Paulo C C

    2009-01-01

    In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have a much wider range of masses (1.3 to > 2 solar masses) than the normal and mildly recycled pulsars found in double neutron star (DNS) systems (1.25 < Mp < 1.44 solar masses). This is very likely to be due to the prolonged accretion episode that is thought to be required to form a MSP. The likely existence of massive MSPs makes them a powerful probe for understanding the behavior of matter at densities larger than that of the atomic nucleus; in particular, the precise measurement of the mass of PSR J1903+0327 ($1.67 +/- 0.01 solar masses) excludes several "soft" equations of state for dense matter.

  11. Eccentricity distribution of wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+-0.02 and the eccentricity distribution can be modeled as f(e) ~= 1.2 e + 0.4. However, wide binaries containing inner subsystems, i.e. triple or higher-order multiples, have significantly smaller eccentricities with the average e = 0.52+-0.05 and the peak at e ~ 0.5. We find that the catalog of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentr...

  12. Eccentricity distribution in the main asteroid belt

    CERN Document Server

    Malhotra, Renu

    2016-01-01

    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 Plummer's (1916) 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 $\\sim0.1$ 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 modeled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Ra...

  13. Super-Eccentric Migrating Jupiters

    CERN Document Server

    Socrates, Aristotle; Dong, Subo; Tremaine, Scott

    2011-01-01

    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 \\dot a \\propto a^0.5 and consequently the number distribution satisfies dN/dlog a\\propto a^0.5. 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.

  14. 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.

  15. Eccentricity evolution in hierarchical triple systems with eccentric outer binaries

    CERN Document Server

    Georgakarakos, Nikolaos

    2014-01-01

    We develop a technique for estimating the inner eccentricity in hierarchical triple systems, with the inner orbit being initially circular, while the outer one is eccentric. We consider coplanar systems with well separated components and comparable masses. The derivation of short period terms is based on an expansion of the rate of change of the Runge-Lenz vector. Then, the short period terms are combined with secular terms, obtained by means of canonical perturbation theory. The validity of the theoretical equations is tested by numerical integrations of the full equations of motion.

  16. Titan's Eccentricity Tides

    Science.gov (United States)

    Iess, L.; Jacobson, R.; Ducci, M.; Stevenson, D. J.; Lunine, J. I.; Armstrong, J. W.; Asmar, S.; Racioppa, P.; Rappaport, N. J.; Tortora, P.

    2011-12-01

    The large eccentricity (e=0.03) of Titan's orbit causes significant variations in the tidal field from Saturn and induces periodic stresses in the satellite body at the orbital period (about 16 days). Peak-to-peak variations of the tidal field (from pericenter to apocenter) are about 18% (6e). If Titan hosts a liquid layer (such as an internal ocean), the gravity field would exhibit significant periodic variations. The response of the body to fast variations of the external, perturbing field is controlled by the Love numbers, defined for each spherical harmonic as the ratio between the perturbed and perturbing potential. For Titan the largest effect is by far on the quadrupole field, and the corresponding Love number is indicated by k2 (assumed to be identical for all degree 2 harmonics). Models of Titan's interior generally envisage a core made up of silicates, surrounded by a layer of high pressure ice, possibly a liquid water or water-ammonia ocean, and an ice-I outer shell, with variations associated with the dehydration state of the core or the presence of mixed rock-ice layers. Previous analysis of Titan's tidal response [1] shows that k2 depends crucially on the presence or absence of an internal ocean. k2 was found to vary from about 0.03 for a purely rocky interior to 0.48 for a rigid rocky core surrounded by an ocean and a thin (20 km) ice shell. A large k2 entails changes in the satellite's quadrupole coefficients by a few percent, enough to be detected by accurate range rate measurements of the Cassini spacecraft. So far, of the many Cassini's flybys of Titan, six were used for gravity measurements. During gravity flybys the spacecraft is tracked from the antennas of NASA's Deep Space Network using microwave links at X- and Ka-band frequencies. A state-of-the-art instrumentation enables range rate measurements accurate to 10-50 micron/s at integration times of 60 s. The first four flybys provided the static gravity field and the moment of inertia factor

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Chronic Eccentric Exercise and the Older Adult.

    Science.gov (United States)

    Gluchowski, Ashley; Harris, Nigel; Dulson, Deborah; Cronin, John

    2015-10-01

    Eccentric exercise has gained increasing attention as a suitable and promising intervention to delay or mitigate the known physical and physiological declines associated with aging. Determining the relative efficacy of eccentric exercise when compared with the more conventionally prescribed traditional resistance exercise will support evidence-based prescribing for the aging population. Thus, original research studies incorporating chronic eccentric exercise interventions in the older adult population were included in this review. The effects of a range of eccentric exercise modalities on muscular strength, functional capacity, body composition, muscle architecture, markers of muscle damage, the immune system, cardiovascular system, endocrine system, and rating of perceived exertion were all reviewed as outcomes of particular interest in the older adult. Muscular strength was found to increase most consistently compared with results from traditional resistance exercise. Functional capacity and body composition showed significant improvements with eccentric endurance protocols, especially in older, frail or sedentary cohorts. Muscle damage was avoided with the gradual progression of novel eccentric exercise, while muscle damage from intense acute bouts was significantly attenuated with repeated sessions. Eccentric exercise causes little cardiovascular stress; thus, it may not generate the overload required to elicit cardiovascular adaptations. An anabolic state may be achievable following eccentric exercise, while improvements to insulin sensitivity have not been found. Finally, rating of perceived exertion during eccentric exercise was often significantly lower than during traditional resistance exercise. Overall, evidence supports the prescription of eccentric exercise for the majority of outcomes of interest in the diverse cohorts of the older adult population.

  2. 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...

  3. Eccentric Exercise: Physiological Characteristics and Acute Responses.

    Science.gov (United States)

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

    2017-04-01

    An eccentric contraction involves the active lengthening of muscle under an external load. The molecular and neural mechanisms underpinning eccentric contractions differ from those of concentric and isometric contractions and remain less understood. A number of molecular theories have been put forth to explain the unexplained observations during eccentric contractions that deviate from the predictions of the established theories of muscle contraction. Postulated mechanisms include a strain-induced modulation of actin-myosin interactions at the level of the cross-bridge, the activation of the structural protein titin, and the winding of titin on actin. Accordingly, neural strategies controlling eccentric contractions also differ with a greater, and possibly distinct, cortical activation observed despite an apparently lower activation at the level of the motor unit. The characteristics of eccentric contractions are associated with several acute physiological responses to eccentrically-emphasised exercise. Differences in neuromuscular, metabolic, hormonal and anabolic signalling responses during, and following, an eccentric exercise bout have frequently been observed in comparison to concentric exercise. Subsequently, the high levels of muscular strain with such exercise can induce muscle damage which is rarely observed with other contraction types. The net result of these eccentric contraction characteristics and responses appears to be a novel adaptive signal within the neuromuscular system.

  4. 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.

  5. 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.......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....

  6. Orbital eccentricities in primordial black hole binaries

    Science.gov (United States)

    Cholis, Ilias; Kovetz, Ely D.; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B.; Raccanelli, Alvise

    2016-10-01

    It was recently suggested that the merger of ˜30 M⊙ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on time scales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO and the Einstein Telescope to such effects. We show that if PBHs make up the dark matter, then roughly one event should have a detectable eccentricity given LIGO's expected sensitivity and observing time of six years. The Einstein Telescope should see O (10 ) such events after ten years.

  7. Aging, Functional Capacity and Eccentric Exercise Training

    Science.gov (United States)

    Gault, Mandy L.; Willems, Mark E.T.

    2013-01-01

    Aging is a multi-factorial process that ultimately induces a decline in our physiological functioning, causing a decreased health-span, quality of life and independence for older adults. Exercise participation is seen as a way to reduce the impact of aging through maintenance of physiological parameters. Eccentric exercise is a model that can be employed with older adults, due to the muscle’s ability to combine high muscle force production with a low energy cost. There may however be a risk of muscle damage before the muscle is able to adapt. The first part of this review describes the process of aging and how it reduces aerobic capacity, muscle strength and therefore functional mobility. The second part highlights eccentric exercise and the associated muscle damage, in addition to the repeated bout effect. The final section reviews eccentric exercise interventions that have been completed by older adults with a focus on the changes in functional mobility. In conclusion, eccentric endurance exercise is a potential training modality that can be applied to older adults for improving muscle strength, aerobic capacity and functional ability. However, further research is needed to assess the effects on aerobic capacity and the ideal prescription for eccentric endurance exercise. PMID:24307968

  8. 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.

  9. Collisional evolution of eccentric planetesimal swarms

    CERN Document Server

    Wyatt, M C; Payne, M J; Churcher, L J

    2009-01-01

    Models for the steady state collisional evolution of low eccentricity planetesimal belts identify debris disks with hot dust at 1AU, like eta Corvi and HD69830, as anomalous since collisional processing should have removed most of the planetesimal mass over their >1 Gyr lifetimes. This paper looks at the effect of large planetesimal eccentricities (e>>0.3) on their collisional lifetime and the amount of mass that can remain at late times M_{late}. For an axisymmetric planetesimal disk with common pericentres and eccentricities e, we find that M_{late} \\propto e^{-5/3}(1+e)^{4/3}(1-e)^{-3}. For a scattered disk-like population (i.e., common pericentres), in the absence of dynamical evolution, the mass evolution at late times would be as if only planetesimals with the largest eccentricity were present. Despite the increased remaining mass, higher eccentricities do not increase the hot emission from the collisional cascade until e>0.99, partly because most collisions occur near pericentre thus increasing the dus...

  10. Gravitational waves from spinning eccentric binaries

    CERN Document Server

    Csizmadia, Péter; Rácz, István; Vasúth, Mátyás

    2012-01-01

    This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity. In addition, by investigating the validity of the energy balance relat...

  11. Unstable force analysis for induction motor eccentricity

    Science.gov (United States)

    Han, Xu; Palazzolo, Alan

    2016-05-01

    The increasing popularity of motors in machinery trains has led to an intensified interest in the forces they produce that may influence machinery vibration. Motor design typically assumes a uniform air gap, however in practice all motors operate with the rotor slightly displaced from the motor centerline in what is referred to as an eccentric position. Rotor center eccentricity can cause a radially unbalanced magnetic field when the motor is operating. This will results in both a radial force pulling the motor further away from the center, and a tangential force which can induce a vibration stability problem. In this paper, a magnetic equivalent circuit MEC modeling method is proposed to calculate both the radial and tangential motor eccentric force. The treatment of tangential force determination is rarely addressed, but it is very important for rotordynamic vibration stability evaluation. The proposed model is also coupled with the motor electric circuit model to provide capability for transient vibration simulations. FEM is used to verify the MEC model. A parametric study is performed on the motor radial and tangential eccentric forces. Also a Jeffcott rotor model is used to study the influence of the motor eccentric force on mechanical vibration stability and nonlinear behavior. Furthermore, a stability criteria for the bearing damping is provided. The motor radial and tangential eccentric forces are both curved fitted to include their nonlinearity in time domain transient simulation for both a Jeffcott rotor model and a geared machinery train with coupled torsional-lateral motion. Nonlinear motions are observed, including limit cycles and bifurcation induced vibration amplitude jumps.

  12. Testing eccentricity pumping mechanisms to model eccentric long period sdB binaries with MESA

    CERN Document Server

    Vos, Joris; Marchant, Pablo; Van Winckel, Hans

    2015-01-01

    Hot subdwarf-B stars in long-period binaries are found to be on eccentric orbits, even though current binary-evolution theory predicts those objects to be circularised before the onset of Roche-lobe overflow (RLOF). We aim to find binary-evolution mechanisms that can explain these eccentric long-period orbits, and reproduce the currently observed period-eccentricity diagram. Three different processes are considered; tidally-enhanced wind mass-loss, phase-dependent RLOF on eccentric orbits and the interaction between a circumbinary disk and the binary. The binary module of the stellar-evolution code MESA (Modules for Experiments in Stellar Astrophysics) is extended to include the eccentricity-pumping processes. The effects of different input parameters on the final period and eccentricity of a binary-evolution model are tested with MESA. The end products of models with only tidally-enhanced wind mass-loss can indeed be eccentric, but these models need to lose too much mass, and invariably end up with a helium ...

  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. Orbital eccentricities in primordial black holes binaries

    CERN Document Server

    Cholis, Ilias; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on timescales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO a...

  15. Density and Eccentricity of Kepler Planets

    CERN Document Server

    Wu, Yanqin

    2012-01-01

    We analyze the transit timing variations obtained by the Kepler mission for 22 sub-jovian planet pairs (17 published, 5 new) that lie close to mean motion resonances. We find that the TTV phases for most of these pairs lie close to zero, consistent with an eccentricity distribution that has a very low RMS value of e ~ 0.01; but about a quarter of the pairs possess much higher eccentricities, up to 0.1 - 0.4. For the low-eccentricity pairs, we are able to statistically remove the effect of eccentricity to obtain planet masses from TTV data. These masses, together with those measured by radial velocity, yield a best fit mass-radius relation M~3 M_E (R/R_E). This corresponds to a constant surface escape velocity of 20km/s. We separate the planets into two distinct groups, "mid-sized" (those greater than 3 R_E), and "compact" (those smaller). All mid-sized planets are found to be less dense than water and therefore contain extensive H/He envelopes, likely comparable in mass to that of their cores. We argue that t...

  16. Vibration of an eccentrically clamped annular plate

    Science.gov (United States)

    Tseng, J.-G.; Wickert, J. A.

    1994-04-01

    Small amplitude vibration of an eccentric annular plate, which is free along its outer edge and clamped along the interior, is investigated through experimental and analytical methods. A disk with this geometry, or a stacked array in which the clamping and symmetry axes of each disk are nominally coincident, is common in data storage and brake systems applications. In the present case, the geometric imperfections on the boundary can have important implications for the disk's dynamic response. Changes that occur in the natural frequency spectrum, the mode shapes, and the free response under eccentric mounting are studied through laboratory measurements and an approximate discrete model of the plate. The natural frequencies and modes are found through global discretization of the Kamke quotient for a classical thin plate. For the axisymmetric geometry, the natural frequencies of the sine and cosine vibration modes for a specified number of nodal diameters are repeated. With increasing eccentricity, on the other hand, each pair of repeated frequencies splits at a rate that depends on the number of nodal diameters. Over a range of clamping and eccentricity ratios, the model's predictions are compared to the measured results.

  17. Chain hexagonal cacti with the extremal eccentric distance sum.

    Science.gov (United States)

    Qu, Hui; Yu, Guihai

    2014-01-01

    Eccentric distance sum (EDS), which can predict biological and physical properties, is a topological index based on the eccentricity of a graph. In this paper we characterize the chain hexagonal cactus with the minimal and the maximal eccentric distance sum among all chain hexagonal cacti of length n, respectively. Moreover, we present exact formulas for EDS of two types of hexagonal cacti.

  18. Eccentricity Pumping Through Circumbinary Disks in Hot Subdwarf Binaries

    Science.gov (United States)

    Vos, J.

    2015-12-01

    Hot subdwarf-B stars in long-period binaries are found to be on eccentric orbits, even though current binary-evolution theory predicts these objects to be circularized before the onset of Roche-lobe overflow (RLOF). We have tested three different eccentricity pumping processes on their viability to reproduce the observed wide sdB population; tidally-enhanced wind mass-loss, phase-dependent RLOF on eccentric orbits and the interaction between a circumbinary (CB) disk and the binary. The binary module of the stellar-evolution code Modules for Experiments in Stellar Astrophysics (MESA) is extended to include the eccentricity-pumping processes, and a parameter study is carried out. We find that models including phase-dependent RLOF or a CB disk can reach the observed periods and eccentricities. However, the models cannot explain the observed correlation between period and eccentricity. Nor can circular short period systems be formed when eccentricity pumping mechanisms are active.

  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. Eccentric Connectivity Index of Chemical Trees

    CERN Document Server

    c, Aleksandar Ili\\'

    2011-01-01

    The eccentric connectivity index $\\xi^c$ is a distance--based molecular structure descriptor that was recently used for mathematical modeling of biological activities of diverse nature. We prove that the broom has maximum $\\xi^c$ among trees with a fixed maximum vertex degree, and characterize such trees with minimum $\\xi^c$\\,. In addition, we propose a simple linear algorithm for calculating $\\xi^c$ of trees.

  1. Habitable Climates: The Influence of Eccentricity

    CERN Document Server

    Dressing, Courtney D; Scharf, Caleb A; Raymond, Sean N

    2010-01-01

    Radiative equilibrium studies that place Earth-like exoplanets on different circular orbits from the parent star do not fully sample the range of plausible habitability conditions in planetary systems. In the outer regions of the habitable zone, the risk of transitioning into a globally frozen "snowball" state poses a threat to the habitability. Here, we use a one-dimensional energy balance climate model (EBM) to examine how obliquity, spin rate, orbital eccentricity, and the fraction of the surface covered by ocean might influence the onset of such a snowball state. Since, for constant semimajor axis, the annual mean stellar irradiation scales with (1-e^2)^(-1/2), one might expect the greatest habitable semimajor axis to scale as (1-e^2)^(-1/4). We find that this standard simple ansatz provides a reasonable lower bound on the outer boundary of the habitable zone, but the influence of both obliquity and ocean fraction can be profound in the context of planets on eccentric orbits. For planets with eccentricity...

  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. Roll Eccentricity Control Using Identified Eccentricity of Top/Bottom Rolls by Roll Force

    Science.gov (United States)

    Imanari, Hiroyuki; Koshinuma, Kazuyoshi

    Roll eccentricity is a periodic disturbance caused by a structure of back up rolls in rolling mills, and it affects product thickness accuracy. It cannot be measured directly by sensors, so it should be identified by measured thickness or measured roll force. When there is a large difference of diameters between top and bottom back up roll, the performance of roll eccentricity control using feedback signals of roll force or thickness has not been so good. Also it has been difficult for the control to be applied from the most head end because it is necessary to identify the roll eccentricity during rolling. A new roll eccentricity control has been developed to improve these disadvantages and to get better performance. The method identifies top and bottom roll eccentricity respectively from one signal of roll force and it can start the control from head end. In this paper the new control method is introduced and actual application results to a hot strip mill are shown.

  4. Effects of eccentric cycle ergometry in alpine skiers.

    Science.gov (United States)

    Gross, M; Lüthy, F; Kroell, J; Müller, E; Hoppeler, H; Vogt, M

    2010-08-01

    Eccentric cycling, where the goal is to resist the pedals, which are driven by a motor, increases muscle strength and size in untrained subjects. We hypothesized that it could also be beneficial for athletes, particularly in alpine skiing, which involves predominantly eccentric contractions at longer muscle lengths. We investigated the effects of replacing part of regular weight training with eccentric cycling in junior male alpine skiers using a matched-pair design. Control subjects ( N=7) executed 1-h weight sessions 3 times per week, which included 4-5 sets of 4 leg exercises. The eccentric group ( N=8) performed only 3 sets, followed by continuous sessions on the eccentric ergometer for the remaining 20 min. After 6 weeks, lean thigh mass increased significantly only in the eccentric group. There was a groupxtime effect on squat-jump height favouring the eccentric group, which also experienced a 6.5% improvement in countermovement-jump height. The ability to finely modulate muscle force during variable eccentric cycling improved 50% (p=0.004) only in the eccentric group. Although eccentric cycling did not significantly enhance isometric leg strength, we believe it is beneficial for alpine skiers because it provides an efficient means for hypertrophy while closely mimicking the type of muscle actions encountered while skiing.

  5. Orbital evolution of eccentric planets in radiative discs

    Science.gov (United States)

    Bitsch, B.; Kley, W.

    2010-11-01

    Context. With an average eccentricity of about 0.29, the eccentricity distribution of extrasolar planets is markedly different from the solar system. Among other scenarios considered, it has been proposed that eccentricity may grow through planet-disc interaction. Recently, it has been noticed that the thermodynamical state of the disc can significantly influence the migration properties of growing protoplanets. However, the evolution of planetary eccentricity in radiative discs has not been considered yet. Aims: In this paper we study the evolution of planets on eccentric orbits that are embedded in a three-dimensional viscous disc and analyse the disc's effect on the orbital evolution of the planet. Methods: We use the three-dimensional hydrodynamical code NIRVANA that includes full tensor viscosity and implicit radiation transport in the flux-limited diffusion approximation. The code uses the FARGO-algorithm to speed up the simulations. First we measure the torque and power exerted on the planet by the disc for fixed orbits, and then we let the planet start with initial eccentricity and evolve it in the disc. Results: For locally isothermal discs we confirm previous results and find eccentricity damping and inward migration for planetary cores. For low eccentricity (e ⪉ 2 H/r) the damping is exponential, while for higher e it follows dot{e} ∝ e-2. In the case of radiative discs, the planets experience an inward migration as long as its eccentricity lies above a certain threshold. After the damping of eccentricity cores with masses below 33 MEarth begin to migrate outward in radiative discs, while higher mass cores always migrate inward. For all planetary masses studied (up to 200 MEarth) we find eccentricity damping. Conclusions: In viscous discs the orbital eccentricity of embedded planets is damped during the evolution independent of the mass. Hence, planet-disc interaction does not seem to be a viable mechanism to explain the observed high eccentricity of

  6. 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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    .354) Nm/kg. CONCLUSION: Normative values for maximal eccentric hip abduction strength in novice runners can be calculated by taking into account the differences in strength across genders and the decline in strength that occurs with increasing age. Age and gender were associated with maximal eccentric hip......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...... 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...

  8. Flow Mode Magnetorheological Dampers with an Eccentric Gap

    OpenAIRE

    Choi, Young-Tai; Norman M. Wereley

    2014-01-01

    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 dam...

  9. Multiarticular isokinetic high-load eccentric training induces large increases in eccentric and concentric strength and jumping performance.

    Science.gov (United States)

    Papadopoulos, Christos; Theodosiou, Konstantinos; Bogdanis, Gregory C; Gkantiraga, Evangelia; Gissis, Ioannis; Sambanis, Michalis; Souglis, Athanasios; Sotiropoulos, Aristomenis

    2014-09-01

    This study investigated the effects of short-term eccentric exercise training using a custom-made isokinetic leg press device, on concentric and eccentric strength and explosiveness as well as jumping performance. Nineteen healthy males were divided into an eccentric (ECC, n = 10) and a control group (CG, n = 9). The ECC group trained twice per week for 8 weeks using an isokinetic hydraulic leg press machine against progressively increasing resistance ranging from 70 to 90% of maximal eccentric force. Jumping performance and maximal force generating capacity were measured before and after eccentric training. In the ECC group, drop jump (DJ) height and maximal power were increased by 13.6 ± 3.2% (p knee, and hip joint angles were also reduced by 33.9 ± 1.1%, 31.1 ± 1.0%, and 32.4 ± 1.6% (all p eccentric and concentric leg press force was increased by 64.9 ± 5.5% (p eccentric force, explosiveness, and DJ performance were markedly increased after only 16 training sessions, possibly because of the high eccentric load attained during the bilateral eccentric leg press exercise performed on this custom-made device.

  10. 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

  11. Asymmetric transition disks: Vorticity or eccentricity?

    CERN Document Server

    Zsom, A; Ghanbari, J

    2013-01-01

    Context. Transition disks typically appear in resolved millimeter observations as giant dust rings surrounding their young host stars. More accurate observations with ALMA have shown several of these rings to be in fact asymmetric: they have lopsided shapes. It has been speculated that these rings act as dust traps, which would make them important laboratories for studying planet formation. It has been shown that an elongated giant vortex produced in a disk with a strong viscosity jump strikingly resembles the observed asymmetric rings. Aims. We aim to study a similar behavior for a disk in which a giant planet is embedded. However, a giant planet can induce two kinds of asymmetries: (1) a giant vortex, and (2) an eccentric disk. We studied under which conditions each of these can appear, and how one can observationally distinguish between them. This is important because only a vortex can trap particles both radially and azimuthally, while the eccentric ring can only trap particles in radial direction. Method...

  12. The Retrogressive movement of eccentric vortex in the Column Vessel

    OpenAIRE

    赤澤, 孝; Akazawa, Takashi

    2012-01-01

    Our experiment found that the center of an eccentric vortex retrogrades and move nutationally when modeled using an eccentric vortex of water in the column vessel. This paper reports that this retrogressive movement is established and caused by the propagation of only one wave. This result is in line with the findings of previous experiments.

  13. 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...

  14. Introducing the Moon's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2014-01-01

    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…

  15. Accurate and efficient waveforms for compact binaries on eccentric orbits

    CERN Document Server

    Huerta, E A; McWilliams, Sean T; O'Shaughnessy, Richard; Yunes, Nicolas

    2014-01-01

    Compact binaries that emit gravitational waves in the sensitivity band of ground-based detectors can have non-negligible eccentricities just prior to merger, depending on the formation scenario. We develop a purely analytic, frequency-domain model for gravitational waves emitted by compact binaries on orbits with small eccentricity, which reduces to the quasi-circular post-Newtonian approximant TaylorF2 at zero eccentricity and to the post-circular approximation of Yunes et al. (2009) at small eccentricity. Our model uses a spectral approximation to the (post-Newtonian) Kepler problem to model the orbital phase as a function of frequency, accounting for eccentricity effects up to ${\\cal{O}}(e^8)$ at each post-Newtonian order. Our approach accurately reproduces an alternative time-domain eccentric waveform model for eccentricities $e\\in [0, 0.4]$ and binaries with total mass less than 12 solar masses. As an application, we evaluate the signal amplitude that eccentric binaries produce in different networks of e...

  16. Eccentric exercise decreases maximal insulin action in humans

    DEFF Research Database (Denmark)

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

    1996-01-01

    1. Unaccustomed eccentric exercise decreases whole-body insulin action in humans. To study the effects of one-legged eccentric exercise on insulin action in muscle and systemically, the euglycaemic clamp technique combined with arterial and bilateral femoral venous catheterization was used. Seven...... 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......) 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 eccentric exercise, muscle and whole-body insulin action is impaired at maximal...

  17. 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......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...... 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...

  18. Local and global dynamics of eccentric astrophysical discs

    CERN Document Server

    Ogilvie, Gordon I

    2014-01-01

    We formulate a local dynamical model of an eccentric disc in which the dominant motion consists of elliptical Keplerian orbits. The model is a generalization of the well known shearing sheet, and is suitable for both analytical and computational studies of the local dynamics of eccentric discs. It is spatially homogeneous in the horizontal dimensions but has a time-dependent geometry that oscillates at the orbital frequency. We show how certain averages of the stress tensor in the local model determine the large-scale evolution of the shape and mass distribution of the disc. The simplest solutions of the local model are laminar flows consisting of a (generally nonlinear) vertical oscillation of the disc. Eccentric discs lack vertical hydrostatic equilibrium because of the variation of the vertical gravitational acceleration around the eccentric orbit, and in some cases because of the divergence of the orbital velocity field associated with an eccentricity gradient. We discuss the properties of the laminar sol...

  19. Eccentric double white dwarfs as LISA sources in globular clusters

    CERN Document Server

    Willems, B; Vecchio, A; Ivanova, N; Rasio, F A; Fregeau, J M; Belczynski, K

    2007-01-01

    We consider the formation of double white dwarfs (DWDs) through dynamical interactions in globular clusters. Such interactions can readily give rise to eccentric DWDs, in contrast to the exclusively circular population that is expected to form in the Galactic disk. We show that for a 5-year Laser Interferometer Space Antenna (LISA) mission and distances as far as the Large Magellanic Cloud, multiple harmonics from eccentric DWDs can be detected at a signal-to-noise ratio higher than 8 for at least a handful of eccentric DWDs, given their formation rate and typical merger lifetimes estimated from current cluster simulations. Consequently the association of eccentricity with stellar-mass LISA sources does not uniquely involve neutron stars, as is usually assumed. Due to the difficulty of detecting these systems with present and planned electromagnetic observatories, LISA could provide unique dynamical identifications of eccentric DWDs in globular clusters.

  20. 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

  1. Red-giant stars in eccentric binaries

    Directory of Open Access Journals (Sweden)

    Beck P. G.

    2015-01-01

    Full Text Available The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs.

  2. FUZZY ECCENTRICITY AND GROSS ERROR IDENTIFICATION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The dominant and recessive effect made by exceptional interferer is analyzed in measurement system based on responsive character, and the gross error model of fuzzy clustering based on fuzzy relation and fuzzy equipollence relation is built. The concept and calculate formula of fuzzy eccentricity are defined to deduce the evaluation rule and function of gross error, on the base of them, a fuzzy clustering method of separating and discriminating the gross error is found. Utilized in the dynamic circular division measurement system, the method can identify and eliminate gross error in measured data, and reduce measured data dispersity. Experimental results indicate that the use of the method and model enables repetitive precision of the system to improve 80% higher than the foregoing system, to reach 3.5 s, and angle measurement error is less than 7 s.

  3. Highly eccentric inspirals into a black hole

    Science.gov (United States)

    Osburn, Thomas; Warburton, Niels; Evans, Charles R.

    2016-03-01

    We model the inspiral of a compact stellar-mass object into a massive nonrotating black hole including all dissipative and conservative first-order-in-the-mass-ratio effects on the orbital motion. The techniques we develop allow inspirals with initial eccentricities as high as e ˜0.8 and initial separations as large as p ˜50 to be evolved through many thousands of orbits up to the onset of the plunge into the black hole. The inspiral is computed using an osculating elements scheme driven by a hybridized self-force model, which combines Lorenz-gauge self-force results with highly accurate flux data from a Regge-Wheeler-Zerilli code. The high accuracy of our hybrid self-force model allows the orbital phase of the inspirals to be tracked to within ˜0.1 radians or better. The difference between self-force models and inspirals computed in the radiative approximation is quantified.

  4. Eccentric Exercise Versus Eccentric Exercise and Soft Tissue Treatment (Astym) in the Management of Insertional Achilles Tendinopathy.

    Science.gov (United States)

    McCormack, Joshua R; Underwood, Frank B; Slaven, Emily J; Cappaert, Thomas A

    Eccentric exercise is commonly used in the management of Achilles tendinopathy (AT) but its effectiveness for insertional AT has been questioned. Soft tissue treatment (Astym) combined with eccentric exercise could result in better outcomes than eccentric exercise alone. Soft tissue treatment (Astym) plus eccentric exercise will be more effective than eccentric exercise alone for subjects with insertional AT. Prospective randomized controlled trial. Level 2. Sixteen subjects were randomly assigned to either a soft tissue treatment (Astym) and eccentric exercise group or an eccentric exercise-only group. Intervention was completed over a 12-week period, with outcomes assessed at baseline, 4, 8, 12, 26, and 52 weeks. Outcomes included the Victorian Institute of Sport Assessment Achilles-Specific Questionnaire (VISA-A), the numeric pain rating scale (NPRS), and the global rating of change (GROC). Significantly greater improvements on the VISA-A were noted in the soft tissue treatment (Astym) group over the 12-week intervention period, and these differences were maintained at the 26- and 52-week follow-ups. Both groups experienced a similar statistically significant improvement in pain over the short and long term. A significantly greater number of subjects in the soft tissue treatment (Astym) group achieved a successful outcome at 12 weeks. Soft tissue treatment (Astym) plus eccentric exercise was more effective than eccentric exercise only at improving function during both short- and long-term follow-up periods. Soft tissue treatment (Astym) plus eccentric exercise appears to be a beneficial treatment program that clinicians should consider incorporating into the management of their patients with insertional AT.

  5. Nonlinear hydrodynamical evolution of eccentric Keplerian discs in two dimensions: validation of secular theory

    CERN Document Server

    Barker, Adrian J

    2016-01-01

    We perform global two-dimensional hydrodynamical simulations of Keplerian discs with free eccentricity over thousands of orbital periods. Our aim is to determine the validity of secular theory in describing the evolution of eccentric discs, and to explore their nonlinear evolution for moderate eccentricities. Linear secular theory is found to correctly predict the structure and precession rates of discs with small eccentricities. However, discs with larger eccentricities (and eccentricity gradients) are observed to precess faster (retrograde relative to the orbital motion), at a rate that depends on their eccentricities (and eccentricity gradients). We derive analytically a nonlinear secular theory for eccentric gas discs, which explains this result as a modification of the pressure forces whenever eccentric orbits in a disc nearly intersect. This effect could be particularly important for highly eccentric discs produced in tidal disruption events, or for narrow gaseous rings; it might also play a role in cau...

  6. Neuromuscular adaptations to isoload versus isokinetic eccentric resistance training.

    Science.gov (United States)

    Guilhem, Gaël; Cornu, Christophe; Maffiuletti, Nicola A; Guével, Arnaud

    2013-02-01

    The purpose of this study was to compare neuromuscular adaptations induced by work-matched isoload (IL) versus isokinetic (IK) eccentric resistance training. A total of 31 healthy subjects completed a 9-wk IL (n = 11) or IK (n = 10) training program for the knee extensors or did not train (control group; n = 10). The IL and IK programs consisted of 20 training sessions, which entailed three to five sets of eight repetitions in the respective modalities. The amount of work and the mean angular velocity were strictly matched between IL and IK conditions. Neuromuscular tests were performed before and after training and consisted of the assessment of quadriceps muscle strength, muscle architecture (vastus lateralis), EMG activity, and antagonist coactivation. IL, but not IK, eccentric resistance training enhanced eccentric strength at short muscle length (+20%), high-velocity eccentric strength (+15%), muscle thickness (+10%), and fascicle angle measured at rest (+11%; P eccentric movements (i.e., at short muscle lengths), which results in greater torque and angular velocities compared with IK actions, is the main determinant of strength and neuromuscular adaptations to eccentric training. These findings have important consequences for the optimization of IL and IK eccentric exercise for resistance training and rehabilitation purposes.

  7. Thermal hydraulics of rod bundles: The effect of eccentricity

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Amit K., E-mail: amit_fmlab@yahoo.co.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S., E-mail: prasad@iitm.ac.in [Thermal Turbomachines Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Patnaik, B.S.V., E-mail: bsvp@iitm.ac.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-10-15

    Highlights: • Present CFD investigation explores, whole bundle eccentricity for the first time. • Fluid flow and thermal characteristics in various subchannels are analyzed. • Mass flux distribution is particularly analyzed to study eccentricity effect. • Higher eccentricity resulted in a shoot up in rod surface temperature distribution. • Both tangential and radial flow in rod bundles has resulted due to eccentricity. -- Abstract: The effect of eccentricity on the fluid flow and heat transfer through a 19-rod bundle is numerically carried out. When the whole bundle shifts downwards with respect to the outer (pressure) tube, flow redistribution happens. This in turn is responsible for changes in mass flux, pressure and differential flow development in various subchannels. The heat flux imposed on the surface of the fuel rods and the mass flux through the subchannels determines the coolant outlet temperatures. The simulations are performed for a coolant flow Reynolds number of 4 × 10{sup 5}. For an eccentricity value of 0.7, the mass flux in the bottom most subchannel (l) was found to decrease by 10%, while the surface temperature of the fuel rod in the vicinity of this subchannel increased by 250% at the outlet section. Parameters of engineering interest including skin friction coefficient, Nusselt number, etc., have been systematically explored to study the effect of eccentricity on the rod bundle.

  8. Insights into the neural control of eccentric contractions.

    Science.gov (United States)

    Duchateau, Jacques; Baudry, Stéphane

    2014-06-01

    The purpose of this brief review is to examine our current knowledge of the neural control of eccentric contractions. The review focuses on three main issues. The first issue considers the ability of individuals to activate muscles maximally during eccentric contractions. Most studies indicate that, regardless of the experimental approach (surface EMG amplitude, twitch superimposition, and motor unit recordings), it is usually more difficult to achieve full activation of a muscle by voluntary command during eccentric contractions than during concentric and isometric contractions. The second issue is related to the specificity of the control strategy used by the central nervous system during submaximal eccentric contractions. This part underscores that although the central nervous system appears to employ a single size-related strategy to activate motoneurons during the different types of contractions, the discharge rate of motor units is less during eccentric contractions across different loading conditions. The last issue addresses the mechanisms that produce this specific neural activation. This section indicates that neural adjustments at both supraspinal and spinal levels contribute to the specific modulation of voluntary activation during eccentric contractions. Although the available information on the control of eccentric contractions has increased during the last two decades, this review indicates that the exact mechanisms underlying the unique neural modulation observed in this type of contraction at spinal and supraspinal levels remains unknown and their understanding represents, therefore, a major challenge for future research on this topic.

  9. Neuromuscular factors contributing to in vivo eccentric moment generation.

    Science.gov (United States)

    Webber, S; Kriellaars, D

    1997-07-01

    Muscle series elasticity and its contribution to eccentric moment generation was examined in humans. While subjects [male, n = 30; age 26.3 +/- 4.8 (SD) yr; body mass 78.8 +/- 13.1 kg] performed an isometric contraction of the knee extensors at 60 degrees of knee flexion, a quick stretch was imposed with a 12 degrees -step displacement at 100 degrees /s. The test was performed at 10 isometric activation levels ranging from 1.7 to 95.2% of maximal voluntary contraction (MVC). A strong linear relationship was observed between the peak imposed eccentric moment derived from quick stretch and the isometric activation level (y = 1.44x + 7.08; r = 0.99). This increase in the eccentric moment is consistent with an actomyosin-dependent elasticity located in series with the contractile element of muscle. By extrapolating the linear relationship to 100% MVC, the predicted maximum eccentric moment was found to be 151% MVC, consistent with in vitro data. A maximal voluntary, knee extensor strength test was also performed (5-95 degrees, 3 repetitions, +/-50, 100, 150, 200, and 250 degrees/s). The predicted maximum eccentric moment was 206% of the angle- and velocity-matched, maximal voluntary eccentric moments. This was attributed to a potent neural regulatory mechanism that limits the recruitment and/or discharge of motor units during maximal voluntary eccentric contractions.

  10. Eccentricity effect of micropatterned surface on contact angle.

    Science.gov (United States)

    Kashaninejad, Navid; Chan, Weng Kong; Nguyen, Nam-Trung

    2012-03-13

    This article experimentally shows that the wetting property of a micropatterned surface is a function of the center-to-center offset distance between successive pillars in a column, referred to here as eccentricity. Studies were conducted on square micropatterns which were fabricated on a silicon wafer with pillar eccentricity ranging from 0 to 6 μm for two different pillar diameters and spacing. Measurement results of the static as well as the dynamic contact angles on these surfaces revealed that the contact angle decreases with increasing eccentricity and increasing relative spacing between the pillars. Furthermore, quantification of the contact angle hysteresis (CAH) shows that, for the case of lower pillar spacing, CAH could increase up to 41%, whereas for the case of higher pillar spacing, this increment was up to 35%, both corresponding to the maximum eccentricity of 6 μm. In general, the maximum obtainable hydrophobicity corresponds to micropillars with zero eccentricity. As the pillar relative spacing decreases, the effect of eccentricity on hydrophobicity becomes more pronounced. The dependence of the wettability conditions of the micropatterned surface on the pillar eccentricity is attributed to the contact line deformation resulting from the changed orientation of the pillars. This finding provides additional insights in design and fabrication of efficient micropatterned surfaces with controlled wetting properties.

  11. Eccentric Exercise Program Design: A Periodization Model for Rehabilitation Applications.

    Science.gov (United States)

    Harris-Love, Michael O; Seamon, Bryant A; Gonzales, Tomas I; Hernandez, Haniel J; Pennington, Donte; Hoover, Brian M

    2017-01-01

    The applied use of eccentric muscle actions for physical rehabilitation may utilize the framework of periodization. This approach may facilitate the safe introduction of eccentric exercise and appropriate management of the workload progression. The purpose of this data-driven Hypothesis and Theory paper is to present a periodization model for isokinetic eccentric strengthening of older adults in an outpatient rehabilitation setting. Exemplar and group data are used to describe the initial eccentric exercise prescription, structured familiarization procedures, workload progression algorithm, and feasibility of the exercise regimen. Twenty-four men (61.8 ± 6.3 years of age) completed a 12-week isokinetic eccentric strengthening regimen involving the knee extensors. Feasibility and safety of the regimen was evaluated using serial visual analog scale (VAS, 0-10) values for self-reported pain, and examining changes in the magnitude of mean eccentric power as a function of movement velocity. Motor learning associated with the familiarization sessions was characterized through torque-time curve analysis. Total work was analyzed to identify relative training plateaus or diminished exercise capacity during the progressive phase of the macrocycle. Variability in the mean repetition interval decreased from 68 to 12% during the familiarization phase of the macrocycle. The mean VAS values were 2.9 ± 2.7 at the start of the regimen and 2.6 ± 2.9 following 12 weeks of eccentric strength training. During the progressive phase of the macrocycle, exercise workload increased from 70% of the estimated eccentric peak torque to 141% and total work increased by 185% during this training phase. The slope of the total work performed across the progressive phase of the macrocycle ranged from -5.5 to 29.6, with the lowest slope values occurring during microcycles 8 and 11. Also, mean power generation increased by 25% when eccentric isokinetic velocity increased from 60 to 90° s(-1) while

  12. Eccentric Exercise Program Design: A Periodization Model for Rehabilitation Applications

    Science.gov (United States)

    Harris-Love, Michael O.; Seamon, Bryant A.; Gonzales, Tomas I.; Hernandez, Haniel J.; Pennington, Donte; Hoover, Brian M.

    2017-01-01

    The applied use of eccentric muscle actions for physical rehabilitation may utilize the framework of periodization. This approach may facilitate the safe introduction of eccentric exercise and appropriate management of the workload progression. The purpose of this data-driven Hypothesis and Theory paper is to present a periodization model for isokinetic eccentric strengthening of older adults in an outpatient rehabilitation setting. Exemplar and group data are used to describe the initial eccentric exercise prescription, structured familiarization procedures, workload progression algorithm, and feasibility of the exercise regimen. Twenty-four men (61.8 ± 6.3 years of age) completed a 12-week isokinetic eccentric strengthening regimen involving the knee extensors. Feasibility and safety of the regimen was evaluated using serial visual analog scale (VAS, 0–10) values for self-reported pain, and examining changes in the magnitude of mean eccentric power as a function of movement velocity. Motor learning associated with the familiarization sessions was characterized through torque-time curve analysis. Total work was analyzed to identify relative training plateaus or diminished exercise capacity during the progressive phase of the macrocycle. Variability in the mean repetition interval decreased from 68 to 12% during the familiarization phase of the macrocycle. The mean VAS values were 2.9 ± 2.7 at the start of the regimen and 2.6 ± 2.9 following 12 weeks of eccentric strength training. During the progressive phase of the macrocycle, exercise workload increased from 70% of the estimated eccentric peak torque to 141% and total work increased by 185% during this training phase. The slope of the total work performed across the progressive phase of the macrocycle ranged from −5.5 to 29.6, with the lowest slope values occurring during microcycles 8 and 11. Also, mean power generation increased by 25% when eccentric isokinetic velocity increased from 60 to 90° s−1

  13. Effect of Eccentricity and Radius Ratio on Fluid Flow and Heat Transfer Inside and Eccentric Semicircular Enclosure

    Institute of Scientific and Technical Information of China (English)

    ProdipKumarDas; ShohelMahmud

    2000-01-01

    The problem of laminar natural convective heat transfer inside an eccentric semicircular enclosure of different radius ratio and eccentricity is investigated numerically,At the same time,combined effect of the radius ratio and eccentricity on fluid flow is also observed with isothermal upper and lower surface.Here laminar,steady nuatural convection heat transfer are predicted for radius ratio R*=1.75,2.0,2.25,2.5.Simulation was carried out for a range of eccentricity,ε=0.0 to 0.6.Governing equations are solved using finite volume method with a body fitted grid with collocated variable arrangement for a range of Grashof numer 101-107 based on R0.Results are presented in the form of constant stream function,isothermal lines,local Nusselt number and average Nusselt number at different angular position.Eccentricity has little dominance on heat transfer rate.But significant effect of eccentricity is observed on flow field.Radius ratio has significant effect on natural convection heat transfer as well as on flow field.At higher eccentricity,bi-cellular flow is observed with one crescent-shape vortex at narrower coross section.This crescent shaped vortex is broken down into two cells with the increase of radius ratio that means transition Grashof number for bi-cellular flow to tri-cellular flow is decreased with the increase of radius ratio.Eccentricity also has the same effect of flow field.Eccentricity has little effect on heat transfer but with the increase of radius ratio.average heat trasfer rate increases.

  14. On Some Bounds and Exact Formulae for Connective Eccentric Indices of Graphs under Some Graph Operations

    Directory of Open Access Journals (Sweden)

    Nilanjan De

    2014-01-01

    Full Text Available The connective eccentric index of a graph is a topological index involving degrees and eccentricities of vertices of the graph. In this paper, we have studied the connective eccentric index for double graph and double cover. Also we give the connective eccentric index for some graph operations such as joins, symmetric difference, disjunction, and splice of graphs.

  15. Effects of recovery modes after knee extensor muscles eccentric contractions

    National Research Council Canada - National Science Library

    Martin, Vincent; Millet, Guillaume Y; Lattier, Grégory; Perrod, Loïc

    2004-01-01

    ...) to hasten the recovery process from eccentric-contraction-induced injury. Before and 30 min, 24 h, 48 h, and 96 h after a one-legged downhill run, electrical stimulations were applied to the femoral nerve of healthy volunteers...

  16. Characterizing Spinning Black Hole Binaries in Eccentric Orbits with LISA

    CERN Document Server

    Key, Joey Shapiro

    2010-01-01

    The Laser Interferometer Space Antenna (LISA) is designed to detect gravitational wave signals from astrophysical sources, including those from coalescing binary systems of compact objects such as black holes. Colliding galaxies have central black holes that sink to the center of the merged galaxy and begin to orbit one another and emit gravitational waves. Some galaxy evolution models predict that the binary black hole system will enter the LISA band with significant orbital eccentricity, while other models suggest that the orbits will already have circularized. Using a full seventeen parameter waveform model that includes the effects of orbital eccentricity, spin precession and higher harmonics, we investigate how well the source parameters can be inferred from simulated LISA data. Defining the reference eccentricity as the value one year before merger, we find that for typical LISA sources, it will be possible to measure the eccentricity to an accuracy of parts in a thousand. The accuracy with which the ec...

  17. 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.

  18. Forever alone? Testing single eccentric planetary systems for multiple companions

    CERN Document Server

    Wittenmyer, Robert A; Horner, Jonathan; Tinney, C G; Butler, R P; Jones, H R A; O'Toole, S J; Bailey, J; Carter, B D; Salter, G S; Wright, D

    2013-01-01

    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.

  19. Exoplanet Orbital Eccentricities Derived From LAMOST-Kepler Analysis

    CERN Document Server

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

    2016-01-01

    The nearly circular (mean eccentricity ~0.06) and coplanar (mean mutual inclination ~3 deg) orbits of the Solar System planets motivated Kant and Laplace to put forth the hypothesis that planets are formed in disks, which has developed into the widely accepted theory of planet formation. Surprisingly, the first several hundred extrasolar planets (mostly Jovian) discovered using the Radial Velocity (RV) technique are commonly on eccentric orbits ( ~ 0.3). 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 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), while the other half are multiple-t...

  20. Near- and Far-Field Optical Response of Eccentric Nanoshells.

    Science.gov (United States)

    Peña-Rodríguez, Ovidio; Díaz-Núñez, Pablo; Rodríguez-Iglesias, Vladimir; Montaño-Priede, Luis; Rivera, Antonio; Pal, Umapada

    2017-12-01

    We study the optical response of eccentric nanoshells (i.e., spherical nanoparticles with an eccentric spherical inclusion) in the near and the far field through finite-difference time-domain simulations. Plasmon hybridization theory is used to explain the obtained results. The eccentricity generates a far-field optical spectrum with various plasmon peaks. The number, position, and width of the peaks depend on the core offset. Near-field enhancements in the surroundings of these structures are significantly larger than those obtained for equivalent concentric nanoshells and, more importantly, they are almost independent of the illumination conditions. This opens up the door for using eccentric nanoshells in applications requiring intense near-field enhancements.

  1. Kepler Planet Masses and Eccentricities from TTV Analysis

    CERN Document Server

    Hadden, Sam

    2016-01-01

    We conduct a uniform analysis of the transit timing variations (TTVs) of 145 planets from 55 Kepler multiplanet systems to infer planet masses and eccentricities. Eighty of these planets do not have previously reported mass and eccentricity measurements. We employ two complementary methods to fit TTVs: Markov chain Monte Carlo simulations based on N-body integration and an analytic fitting approach. Mass measurements of 49 planets, including 12 without previously reported masses, meet our criterion for classification as robust. Using mass and radius measurements, we infer the masses of planets' gaseous envelopes for both our TTV sample as well as transiting planets with radial velocity observations. Insight from analytic TTV formulae allows us to partially circumvent degeneracies inherent to inferring eccentricities from TTV observations. We find that planet eccentricities are generally small, typically a few percent, but in many instances are non-zero.

  2. Growth of eccentric modes in disc-planet interactions

    CERN Document Server

    Teyssandier, Jean

    2016-01-01

    We formulate a set of linear equations that describe the behaviour of small eccentricities in a protoplanetary system consisting of a gaseous disc and a planet. Eccentricity propagates through the disc by means of pressure and self-gravity, and is exchanged with the planet via secular interactions. Excitation and damping of eccentricity can occur through Lindblad and corotation resonances, as well as viscosity. We compute normal modes of the coupled disc-planet system in the case of short-period giant planets orbiting inside an inner cavity, possibly carved by the stellar magnetosphere. Three-dimensional effects allow for a mode to be trapped in the inner parts of the disc. This mode can easily grow within the disc's lifetime. An eccentric mode dominated by the planet can also grow, although less rapidly. We compute the structure and growth rates of these modes and their dependence on the assumed properties of the disc.

  3. Achilles tendinopathy modulates force frequency characteristics of eccentric exercise.

    Science.gov (United States)

    Grigg, Nicole L; Wearing, Scott C; O'Toole, John M; Smeathers, James E

    2013-03-01

    Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.

  4. TTVFaster: First order eccentricity transit timing variations (TTVs)

    Science.gov (United States)

    Agol, Eric; Deck, Katherine

    2016-04-01

    TTVFaster implements analytic formulae for transit time variations (TTVs) that are accurate to first order in the planet-star mass ratios and in the orbital eccentricities; the implementations are available in several languages, including IDL, Julia, Python and C. These formulae compare well with more computationally expensive N-body integrations in the low-eccentricity, low mass-ratio regime when applied to simulated and to actual multi-transiting Kepler planet systems.

  5. Eccentric hamstring strength and hamstring injury risk in Australian footballers.

    Science.gov (United States)

    Opar, David A; Williams, Morgan D; Timmins, Ryan G; Hickey, Jack; Duhig, Steven J; Shield, Anthony J

    2015-04-01

    Are eccentric hamstring strength and between-limb imbalance in eccentric strength, measured during the Nordic hamstring exercise, risk factors for hamstring strain injury (HSI)? Elite Australian footballers (n = 210) from five different teams participated. Eccentric hamstring strength during the Nordic exercise was obtained at the commencement and conclusion of preseason training and at the midpoint of the season. Injury history and demographic data were also collected. Reports on prospectively occurring HSI were completed by the team medical staff. Relative risk (RR) was determined for univariate data, and logistic regression was employed for multivariate data. Twenty-eight new HSI were recorded. Eccentric hamstring strength below 256 N at the start of the preseason and 279 N at the end of the preseason increased the risk of future HSI 2.7-fold (RR, 2.7; 95% confidence interval, 1.3 to 5.5; P = 0.006) and 4.3-fold (RR, 4.3; 95% confidence interval, 1.7 to 11.0; P = 0.002), respectively. Between-limb imbalance in strength of greater than 10% did not increase the risk of future HSI. Univariate analysis did not reveal a significantly greater RR for future HSI in athletes who had sustained a lower limb injury of any kind within the last 12 months. Logistic regression revealed interactions between both athlete age and history of HSI with eccentric hamstring strength, whereby the likelihood of future HSI in older athletes or athletes with a history of HSI was reduced if an athlete had high levels of eccentric strength. Low levels of eccentric hamstring strength increased the risk of future HSI. Interaction effects suggest that the additional risk of future HSI associated with advancing age or previous injury was mitigated by higher levels of eccentric hamstring strength.

  6. 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....

  7. 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

  8. 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.

  9. Eccentricity in Zone Routing Protocol for MANET

    Directory of Open Access Journals (Sweden)

    Mrs Komal Nair

    2012-06-01

    Full Text Available A Mobile Ad-Hoc Network (MANET is a decentralized network of autonomous mobile nodes, able to communicate with each other over wireless links. Due to the mobility of the nodes, the topology ofthe network changes spontaneously, therefore use of conventional routing tables maintained at fixed points (routers is not suggested. Such a network may operate in a standalone fashion. There are variousrouting protocols available for MANETs. The most popular ones are DSR, DSDV and ZRP .The zone routing protocol (ZRP is a hybrid routing protocol that proactively maintains routes within a localregion of the network. ZRP can be configured for a particular network through adjustment of a single parameter, the routing zone radius. In this paper, we address the issue of configuring the ZRP to providethe best performance for a particular network at any time with the concept of eccentricity. The results illustrate the important characteristics of different protocols based on their performance and thus suggest some improvements in the respective protocol. The tools used for the simulation are NS2 which is the main simulator, NAM (Network Animator and Tracegraph which is used for preparing the graphs from the trace files.

  10. Highly eccentric inspirals into a black hole

    CERN Document Server

    Osburn, Thomas; Evans, Charles R

    2015-01-01

    We model the inspiral of a compact stellar-mass object into a massive non-rotating black hole including all dissipative and conservative first-order-in-the-mass-ratio effects on the orbital motion. The techniques we develop allow inspirals with initial eccentricities as high as $e\\sim0.8$ and initial separations as large as $\\sim 100M$ to be evolved through many thousands of orbits up to the onset of the plunge into the black hole. The inspiral is computed using an osculating elements scheme driven by a hybridized self-force model, which combines Lorenz-gauge self-force results with highly accurate flux data from a Regge-Wheeler-Zerilli code. The high accuracy of our hybrid self-force model allows the orbital phase of the inspirals to be tracked to within $\\sim0.1$ radians or better. The difference between self-force models and inspirals computed in the radiative approximation is quantified.

  11. The Solar System and the Exoplanet Orbital Eccentricity - Multiplicity Relation

    CERN Document Server

    Limbach, Mary Anne

    2014-01-01

    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 anti-correlation of orbital eccentricity with multiplicity (number of planets in the system) among catalogued RV systems. The mean, median and rough distribution of eccentricities of Solar System planets fits an extrapolation of this anti-correlation to the eight planet case rather precisely. 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 model of this relationship implies that approximately 80% of the one planet and 25% of the two...

  12. 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

  13. Initial partonic eccentricity fluctuations in a multiphase transport model

    Science.gov (United States)

    Ma, L.; Ma, G. L.; Ma, Y. G.

    2016-10-01

    Initial partonic eccentricities in Au+Au collisions at center-of-mass energy √{sN N}=200 GeV are investigated by using a multiphase transport model with a string-melting scenario. The initial eccentricities in different order of harmonics are studied by using participant and cumulant definitions. Eccentricity in terms of second-, fourth- and sixth-order cumulants as a function of number of participant nucleons are compared systematically with the traditional participant definition. The ratio of the cumulant eccentricities ɛ {4 }/ɛ {2 } and ɛ {6 }/ɛ {4 } are studied in comparison with the ratio of the corresponding flow harmonics. The conversion coefficients (vn/ɛn ) are explored up to fourth-order harmonics based on the cumulant method. Furthermore, studies on transverse momentum (pT) and pseudorapidity (η ) dependencies of eccentricities and their fluctuations are presented. As in ideal hydrodynamics, initial eccentricities are expected to be closely related to the final flow harmonics in relativistic heavy-ion collisions, studies of the fluctuating initial condition in the AMPT model will shed light on the tomography properties of the initial source geometry.

  14. Crowding and eccentricity determine reading rate.

    Science.gov (United States)

    Pelli, Denis G; Tillman, Katharine A; Freeman, Jeremy; Su, Michael; Berger, Tracey D; Majaj, Najib J

    2007-10-26

    Bouma's law of crowding predicts an uncrowded central window through which we can read and a crowded periphery through which we cannot. The old discovery that readers make several fixations per second, rather than a continuous sweep across the text, suggests that reading is limited by the number of letters that can be acquired in one fixation, without moving one's eyes. That "visual span" has been measured in various ways, but remains unexplained. Here we show (1) that the visual span is simply the number of characters that are not crowded and (2) that, at each vertical eccentricity, reading rate is proportional to the uncrowded span. We measure rapid serial visual presentation (RSVP) reading rate for text, in both original and scrambled word order, as a function of size and spacing at central and peripheral locations. As text size increases, reading rate rises abruptly from zero to maximum rate. This classic reading rate curve consists of a cliff and a plateau, characterized by two parameters, critical print size and maximum reading rate. Joining two ideas from the literature explains the whole curve. These ideas are Bouma's law of crowding and Legge's conjecture that reading rate is proportional to visual span. We show that Legge's visual span is the uncrowded span predicted by Bouma's law. This result joins Bouma and Legge to explain reading rate's dependence on letter size and spacing. Well-corrected fluent observers reading ordinary text with adequate light are limited by letter spacing (crowding), not size (acuity). More generally, it seems that this account holds true, independent of size, contrast, and luminance, provided only that text contrast is at least four times the threshold contrast for an isolated letter. For any given spacing, there is a central uncrowded span through which we read. This uncrowded span model explains the shape of the reading rate curve. We test the model in several ways. We use a "silent substitution" technique to measure the

  15. Joint-specific power loss after eccentric exercise.

    Science.gov (United States)

    Elmer, Steven J; Martin, James C

    2010-09-01

    Previous investigators have reported changes in maximal power after eccentric exercise. The influence of eccentric joint-specific power absorption on subsequent concentric joint-specific power production during multijoint actions has not been reported. Our purposes were to determine the extent to which ankle, knee, and hip joint actions absorbed power during eccentric cycling (ECCcyc) and to evaluate changes in power produced by those joint actions during subsequent maximal concentric cycling (CONcyc). We hypothesized that joint actions that absorbed the most power during ECCcyc would exhibit the greatest reductions in power during subsequent maximal CONcyc. Nineteen cyclists performed baseline trials of maximal single-leg CONcyc immediately before and 24 h after acute single-leg ECCcyc (5 min, 40% maximum single-leg CONcyc power). Pedal forces and limb kinematics were determined with a force-sensing pedal and instrumented spatial linkage system, respectively. Joint-specific powers were calculated using inverse dynamics and averaged over complete crank revolutions and over extension and flexion phases. The largest power-absorbing actions during ECCcyc were eccentric knee extensor activity (-185 +/- 12 W) followed by eccentric hip extensor activity (-92 +/- 12 W). Power absorbed through ankle joint actions was small (-10 +/- 2 W). At 24 h, pedal power produced during maximal CONcyc was reduced by 11% +/- 3% relative to baseline. Compared with baseline, knee extension power was reduced by 19% +/- 0 7%, whereas hip extension power did not differ. Power absorbed through eccentric knee extension actions significantly reduced knee extension power produced during subsequent maximal CONcyc. Even with reduced knee extensor function, participants were able to deliver 89% of their baseline power to the environment. These results have implications for individuals who must continue to perform multijoint activities after eccentric exercise.

  16. Eccentric endurance exercise economically improves metabolic and inflammatory risk factors.

    Science.gov (United States)

    Zeppetzauer, Markus; Drexel, Heinz; Vonbank, Alexander; Rein, Philipp; Aczel, Stefan; Saely, Christoph H

    2013-08-01

    Exercise is a cornerstone of cardiovascular prevention. Because many individuals are not willing or not able to perform regular exercise, new methods of exercise (like eccentric exercise) are necessary. Eccentric endurance exercise is supposed to be less strenuous than concentric exercise but its effects on glucose and lipid metabolism in relation to energy expenditure are unclear. We randomly allocated 45 healthy sedentary individuals to one of two groups, each hiking upwards or downwards for 2 months, with a crossover for a further 2 months; for the opposite way, a cable car was used. The difference in altitude was 540 metres; the distance was covered between three and five times a week. Energy expenditure was assessed for each hiking period. Both eccentric and concentric endurance exercise improved glucose tolerance vs. baseline (by 4.1%, p = 0.136; 6.2%, p = 0.023, respectively). Of note, adjustment for energy expenditure per exercise unit (127 ± 22 kcal/unit with eccentric and 442 ± 78 kcal/unit with concentric exercise) revealed a significantly greater improvement of glucose tolerance per kilocalorie spent by eccentric than by concentric exercise (4-times more economical; 0.1123 mg h/dl/kcal vs. 0.0245 mg h/dl/kcal; p = 0.038). Also the decrease of low-density lipoprotein (LDL) cholesterol per kilocalorie spent was significantly stronger with eccentric exercise (0.0982 mg/dl/kcal vs. 0.0346 mg/dl/kcal, p = 0.014). Serum levels of C-reactive protein and creatine kinase activity were reduced in both groups. Eccentric endurance exercise economically improves glucose tolerance and LDL cholesterol. It therefore is a promising new exercise modality for individuals who are not able to participate in more strenuous exercise regimens.

  17. 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

  18. 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

    2016-10-01

    The nearly circular (mean eccentricity e¯≈0.06) and coplanar (mean mutual inclination i¯≈3°) 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 (e¯≈0.3). 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 e¯≈0.3, whereas the multiples are on nearly circular (e¯=0.04-0.04+0.03) and coplanar (i¯=1.4-1.1+0.8 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 [×i¯] between mean eccentricities and mutual inclinations. The prevalence of circular orbits and the common relation may imply that the solar system is not so atypical in the galaxy after all.

  19. Serial assessment of local peripheral vascular function after eccentric exercise.

    Science.gov (United States)

    Stacy, Mitchel R; Bladon, Kallie J; Lawrence, Jennifer L; McGlinchy, Sarah A; Scheuermann, Barry W

    2013-12-01

    Muscle damage is a common response to unaccustomed eccentric exercise; however, the effects of skeletal muscle damage on local vascular function and blood flow are poorly understood. This study examined serial local vascular responses to flow-mediated (endothelial-dependent) and nitroglycerin-mediated (endothelial-independent) dilation in the brachial artery after strenuous eccentric exercise and serially assessed resting blood flow. Ten healthy males performed 50 maximal eccentric unilateral arm contractions to induce muscle damage to the biceps brachii. Changes in maximal isometric strength and vascular responses were assessed 1, 24, 48, and 96 h after exercise. Mean blood velocities and arterial diameters, measured with Doppler ultrasound, were used to calculate blood flow and shear stress (expressed as area under the curve). Eccentric exercise resulted in impaired maximal isometric strength for up to 96 h (p exercise, 9.4% ± 2.6%; 1 h after exercise, 5.1% ± 2.2%) and nitroglycerin responses (before exercise, 26.3% ± 6.5%; 1 h after exercise, 20.7% ± 4.7%) were observed in the 1 h after exercise and remained lower for 96 h (p exercise and remained impaired for 48 h (p eccentric exercise leads to impaired local endothelial and vascular smooth muscle function. Lower shear stress after exercise might contribute to the observed reduction in flow-mediated dilation responses, but the mechanism responsible for the attenuated endothelial-independent vasodilation remains unclear.

  20. Eccentric error and compensation in rotationally symmetric laser triangulation

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Gao Jun; Wang Xiaojia; Johannes Eckstein; Peter Ott

    2007-01-01

    Rotationally symmetric triangulation (RST) sensor has more flexibility and less uncertainty limits becauseof the abaxial rotationally symmetric optical system.But if the incident laser is eccentric,the symmetry of the imagewill descend,and it will result in the eccentric error especially when some part of the imaged ring is blocked.Themodel of rotationally symmetric triangulation that meets the Schimpflug condition is presented in this paper.The errorfrom eccentric incident 1aser is analysed.It iS pointed out that the eccentric error is composed of two parts.one is acosine in circumference and proportional to the eccentric departure factor,and the other is a much smaller quadricfactor of the departure.When the ring is complete,the first error factor is zero because it is integrated in whole ring,but if some part of the ring iS blocked,the first factor will be the main error.Simulation verifies the result of the a-nalysis.At last,a compensation method to the error when some part of the ring is lost is presented based on neuralnetwork.The results of experiment show that the compensation will make the absolute maximum error descend tohalf,and the standard deviation of error descends to 1/3.

  1. Temporary Capture of Asteroids by an Eccentric Planet

    Science.gov (United States)

    Higuchi, A.; Ida, S.

    2017-04-01

    We have investigated the probability of temporary capture of asteroids in eccentric orbits by a planet in a circular or eccentric orbit through analytical and numerical calculations. We found that, in the limit of the circular orbit, the capture probability is ∼0.1% of encounters to the planet’s Hill sphere, independent of planetary mass and semimajor axis. In general, temporary capture becomes more difficult as the planet’s eccentricity ({e}{{p}}) increases. We found that the capture probability is almost independent of {e}{{p}} until a critical value ({e}{{p}}{{c}}) that is given by ≃5 times the Hill radius scaled by the planet’s semimajor axis. For {e}{{p}}> {e}{{p}}{{c}}, the probability decreases approximately in proportion to {e}{{p}}-1. The current orbital eccentricity of Mars is several times larger than {e}{{p}}{{c}}. However, since the range of secular change in Martian eccentricity overlaps {e}{{p}}{{c}}, the capture of minor bodies by Mars in the past is not ruled out.

  2. 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.

  3. Investigating Dynamics of Eccentricity in Turbomachines

    Science.gov (United States)

    Baun, Daniel

    2010-01-01

    A methodology (and hardware and software to implement the methodology) has been developed as a means of investigating coupling between certain rotordynamic and hydrodynamic phenomena in turbomachines. Originally, the methodology was intended for application in an investigation of coupled rotordynamic and hydrodynamic effects postulated to have caused high synchronous vibration in the space shuttle s high-pressure oxygen turbopump (HPOTP). The methodology can also be applied in investigating (for the purpose of developing means of suppressing) undesired hydrodynamic rotor/stator interactions in turbomachines in general. The methodology and the types of phenomena that can be investigated by use of the methodology are best summarized by citing the original application as an example. In that application, in consideration of the high synchronous vibration in the space-shuttle main engine (SSME) HPOTP, it was determined to be necessary to perform tests to investigate the influence of inducer eccentricity and/or synchronous whirl motion on inducer hydrodynamic forces under prescribed flow and cavitation conditions. It was believed that manufacturing tolerances of the turbopump resulted in some induced runout of the pump rotor. Such runout, if oriented with an inducer blade, would cause that blade to run with tip clearance smaller than the tip clearances of the other inducer blades. It was hypothesized that the resulting hydraulic asymmetry, coupled with alternating blade cavitation, could give rise to the observed high synchronous vibration. In tests performed to investigate this hypothesis, prescribed rotor whirl motions have been imposed on a 1/3-scale water-rig version of the SSME LPOTP inducer (which is also a 4-biased inducer having similar cavitation dynamics as the HPOTP) in a magnetic-bearing test facility. The particular magnetic-bearing test facility, through active vibration control, affords a capability to impose, on the rotor, whirl orbits having shapes and

  4. 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 ......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...... the increase in xanthine oxidase in the muscle there were no detectable changes in the levels of muscle malondialdehyde or in plasma antioxidant capacity up to 4 days post-exercise. 5. It is concluded that eccentric exercise leads to an increased level of xanthine oxidase in human muscle and that the increase...

  5. Eccentric exercise as an adjuvant to influenza vaccination in humans.

    Science.gov (United States)

    Edwards, Kate M; Burns, Victoria E; Allen, Louise M; McPhee, Jamie S; Bosch, Jos A; Carroll, Douglas; Drayson, Mark; Ring, Christopher

    2007-02-01

    The immune response to vaccination in animals can be enhanced by exposure to acute stress at the time of vaccination. The efficacy of this adjuvant strategy for vaccination in humans requires investigation. The current study employed a randomised controlled trial design to examine the effects of eccentric exercise prior to influenza vaccination on the antibody and cell-mediated responses. Sixty young healthy adults (29 men, 31 women) performed eccentric contractions of the deltoid and biceps brachii muscles of the non-dominant arm (exercise group) or rested quietly (control group), and were vaccinated 6h later in the non-dominant arm. Change in arm circumference and pain were measured to assess the physiological response to exercise. Antibody titres were measured pre-vaccination and at 6- and 20-week follow-ups. Interferon-gamma in response to in vitro stimulation by the whole vaccine, an index of the cell-mediated response, was measured 8 weeks post-vaccination. Interferon-gamma responses were enhanced by exercise in men, whereas antibody titres were enhanced by eccentric exercise in women but not in men. Men showed greater increase in arm circumference after eccentric exercise than women but there was no difference in reported pain. The interferon-gamma response was positively associated with the percentage increase in arm circumference among the exercise group. Eccentric exercise exerted differential effects on the response to vaccination in men and women, with enhancement of the antibody response in women, but enhancement of the cell-mediated response in men. Eccentric exercise of the muscle at the site of vaccine administration should be explored further as a possible behavioural adjuvant to vaccination.

  6. Hot Jupiters from Coplanar High-eccentricity Migration

    Science.gov (United States)

    Petrovich, Cristobal

    2015-05-01

    We study the possibility that hot Jupiters (HJs) are formed through the secular gravitational interactions between two planets in eccentric orbits with relatively low mutual inclinations (≲ 20{}^\\circ ) and friction due to tides raised on the planet by the host star. We term this migration mechanism Coplanar High-eccentricity Migration (CHEM) because, like disk migration, it allows for migration to occur on the same plane in which the planets formed. CHEM can operate from the following typical initial configurations: (i) the inner planet in a circular orbit and the outer planet with an eccentricity ≳ 0.67 for {{m}in}/{{m}out}{{({{a}in}/{{a}out})}1/2}≲ 0.3; (ii) two eccentric (≳ 0.5) orbits for {{m}in}/{{m}out}{{({{a}in}/{{a}out})}1/2}≲ 0.16. A population synthesis study of hierarchical systems of two giant planets using the observed eccentricity distribution of giant planets shows that CHEM produces HJs with low stellar obliquities (≲ 30{}^\\circ ), with a semi-major axis distribution that matches the observations, and at a rate that can account for their observed occurrence. A different mechanism is needed to create large obliquity HJs, either a different migration channel or a mechanism that tilts the star or the protoplanetary disk. CHEM predicts that HJs should have distant (a≳ 5 AU) and massive (most likely ˜1-3 times more massive than the HJ) companions with relatively low mutual inclinations (≲ 20{}^\\circ ) and moderately high eccentricities (e˜ 0.2-0.5).

  7. On the Eccentricity Excitation in Post-main-sequence Binaries

    Science.gov (United States)

    Rafikov, Roman R.

    2016-10-01

    Several classes of stellar binaries with post-main-sequence (post-MS) components—millisecond pulsars with the white dwarf companions (MSP+WD) and periods of {P}b∼ 30 days, binaries hosting post-asymptotic giant branch stars, or barium stars with {P}b ∼ several years—feature high eccentricities (up to 0.4) despite the expectation of their efficient tidal circularization during their post-MS evolution. It was suggested that the eccentricities of these binaries can be naturally excited by their tidal coupling to the circumbinary disk, formed by the material ejected from the binary. Here we critically reassess this idea using simple arguments rooted in the global angular momentum conservation of the disk+binary system. Compared to previous studies, we (1) fully account for the viscous spreading of the circumbinary disk, (2) consider the possibility of reaccretion from the disk onto the binary (in agreement with simulations and empirical evidence), and (3) allow for the reduced viscosity after the disk expands, cools, and forms dust. These ingredients conspire to significantly lower the efficiency of eccentricity excitation by the disk tides. We find that explaining eccentricities of the post-MS binaries is difficult and requires massive (≳ {10}-2 {M}ȯ ), long-lived (≳ {10}5 years) circumbinary disks that do not reaccrete. While disk tides may account for the eccentricities of the MSP+WD binaries, we show reaccretion to also be detrimental for these systems. Reduced efficiency of the disk-driven excitation motivates the study of alternative mechanisms for producing the peculiar eccentricities of the post-MS binaries.

  8. Eccentric contractions lead to myofibrillar dysfunction in muscular dystrophy.

    Science.gov (United States)

    Blaauw, Bert; Agatea, Lisa; Toniolo, Luana; Canato, Marta; Quarta, Marco; Dyar, Kenneth A; Danieli-Betto, Daniela; Betto, Romeo; Schiaffino, Stefano; Reggiani, Carlo

    2010-01-01

    It is commonly accepted that skeletal muscles from dystrophin-deficient mdx mice are more susceptible than those from wild-type mice to damage from eccentric contractions. However, the downstream mechanisms involved in this enhanced force drop remain controversial. We studied the reduction of contractile force induced by eccentric contractions elicited in vivo in the gastrocnemius muscle of wild-type mice and three distinct models of muscle dystrophy: mdx, alpha-sarcoglycan (Sgca)-null, and collagen 6A1 (Col6a1)-null mice. In mdx and Sgca-null mice, force decreased 35% compared with 14% in wild-type mice. Drop of force in Col6a1-null mice was comparable to that in wild-type mice. To identify the determinants of the force drop, we measured force generation in permeabilized fibers dissected from gastrocnemius muscle that had been exposed in vivo to eccentric contractions and from the contralateral unstimulated muscle. A force loss in skinned fibers after in vivo eccentric contractions was detectable in fibers from mdx and Sgca-null, but not wild-type and Col6a1-null, mice. The enhanced force reduction in mdx and Sgca-null mice was observed only when eccentric contractions were elicited in vivo, since eccentric contractions elicited in vitro had identical effects in wild-type and dystrophic skinned fibers. These results suggest that 1) the enhanced force loss is due to a myofibrillar impairment that is present in all fibers, and not to individual fiber degeneration, and 2) the mechanism causing the enhanced force reduction is active in vivo and is lost after fiber permeabilization.

  9. Effects from Periastron Advance of Eccentric Binary Stars

    Institute of Scientific and Technical Information of China (English)

    李瑾; 仲元红; 潘宇

    2012-01-01

    In this paper,we discuss the coefficients of Gravitational waveform due to eccentric binaries periastron advance with evolved eccentricity.For the basic harmonic modes(n ≤ 5),the frequency split and corresponding relative strengths in the spectrum are figured out.Taking the well known binary systems PSRB 1913+16 and PSRB 1534+12 as examples,we study the dominant harmonic and its frequency split caused by periastron advance in the spectra,and give an estimation of detectability for PSRB 1913+16 and PSRB 1534+12,which are the promising targets for space observatories of gravitational wave.

  10. 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

  11. A complete waveform model for compact binaries on eccentric orbits

    Science.gov (United States)

    Huerta, Eliu; Agarwal, Bhanu; George, Daniel; Kumar, Prayush

    2016-03-01

    The detection of compact binaries with significant eccentricity in the sensitivity band of gravitational wave detectors will provide critical insights on the dynamics and formation channels of these events. In order to search for these systems and place constraints on their rates, we present an inspiral-merger-ringdown time domain waveform model that describes the GW emission from compact binaries on orbits with low to moderate values of eccentricity. We use this model to explore the detectability of these events in the context of advanced LIGO.

  12. Progressive Resistance Exercise with Eccentric Loading for the Management of Knee Osteoarthritis

    National Research Council Canada - National Science Library

    Hernandez, Haniel J; McIntosh, Valerie; Leland, Azadeh; Harris-Love, Michael O

    2015-01-01

    .... The use of an eccentric training paradigm may prove to be beneficial for older adults with knee OA since eccentric muscle actions are involved in the energy absorption at the knee joint during gait...

  13. 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

  14. 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.

  15. The effect of eccentricity and spatiotemporal energy on motion silencing.

    Science.gov (United States)

    Choi, Lark Kwon; Bovik, Alan C; Cormack, Lawrence K

    2016-01-01

    The now well-known motion-silencing illusion has shown that salient changes among a group of objects' luminances, colors, shapes, or sizes may appear to cease when objects move rapidly (Suchow & Alvarez, 2011). It has been proposed that silencing derives from dot spacing that causes crowding, coherent changes in object color or size, and flicker frequencies combined with dot spacing (Choi, Bovik, & Cormack, 2014; Peirce, 2013; Turi & Burr, 2013). Motion silencing is a peripheral effect that does not occur near the point of fixation. To better understand the effect of eccentricity on motion silencing, we measured the amount of motion silencing as a function of eccentricity in human observers using traditional psychophysics. Fifteen observers reported whether dots in any of four concentric rings changed in luminance over a series of rotational velocities. The results in the human experiments showed that the threshold velocity for motion silencing almost linearly decreases as a function of log eccentricity. Further, we modeled the response of a population of simulated V1 neurons to our stimuli. We found strong matches between the threshold velocities on motion silencing observed in the human experiment and those seen in the energy model of Adelson and Bergen (1985). We suggest the plausible explanation that as eccentricity increases, the combined motion-flicker signal falls outside the narrow spatiotemporal frequency response regions of the modeled receptive fields, thereby reducing flicker visibility.

  16. 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...

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

    CERN Document Server

    Schenke, Björn; Venugopalan, Raju

    2013-01-01

    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 distributions in A+A collisions to the flow harmonic distributions in 10 centrality classes measured by the ATLAS collaboration.

  18. Reliability of power output during eccentric sprint cycling.

    Science.gov (United States)

    Brughelli, Matt; Van Leemputte, Marc

    2013-01-01

    The purpose of this study was to determine the reliability of power outputs during maximal intensity eccentric cycling over short durations (i.e., eccentric sprint cycling) on a "motor-driven" isokinetic ergometer. Fourteen physically active male subjects performed isokinetic eccentric cycling sprints at 40, 60, 80, 100, and 120 revolutions per minute (rpm) on 4 separate occasions (T1-T4). Each sprint lasted for 6 seconds, and absolute measures of mean power (MP) and peak power (PP) per revolution were recorded. Significant increases in MP and PP were observed between T1 and subsequent trials, but no significant differences were identified between T2, T3, and T4. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated to reflect within-subject and between-session reliability of MP and PP at each cadence. The CV improved to below 10% for cadences of 60, 80, 100, and 120 rpm between T3 and T4, and the majority of ICC values improved to above 0.90. The remaining ICC values remained in the moderate range between T3 and T4 (i.e., 0.82-0.89). Coefficient of variation and ICC values for the 40 rpm cadence remained at unacceptable levels throughout the 4 trials and thus should be avoided in future investigations. The results of this study indicate that reliable power outputs may be obtained after 2 familiarization sessions during eccentric sprint cycling at cadences ranging from 60 to 120 rpm.

  19. 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.

  20. Facilitation of quadriceps activation is impaired following eccentric exercise.

    Science.gov (United States)

    Hedayatpour, N; Arendt-Nielsen, L; Falla, D

    2014-04-01

    Contracting the knee flexor muscles immediately before a maximum voluntary contraction (MVC) of knee extension increases the maximal force that the extensor muscles can exert. It is hypothesized that this phenomenon can be impaired by muscle fiber damage following eccentric exercise [delayed onset muscle soreness (DOMS)]. This study investigates the effect of eccentric exercise and DOMS on knee extension MVC immediately following a reciprocal-resisted knee flexion contraction. Electromyography (EMG) was recorded from the knee extensors and flexors of 12 healthy men during knee extension MVCs performed in a reciprocal (maximal knee extension preceded by resisted knee flexion), and nonreciprocal condition (preceded by relaxation of the knee flexors). At baseline, knee extension MVC force was greater during the reciprocal condition (P eccentric exercise, the MVC force was not different between conditions. Similarly, at baseline, the EMG amplitude of the quadriceps during the MVC was larger for the reciprocal condition (P eccentric exercise abolished the facilitation of force production for the knee extensors, which normally occurs when maximum knee extension is preceded by activation of the knee flexors.

  1. Systemic cytokine response to three bouts of eccentric exercise

    Science.gov (United States)

    Cornish, Stephen M.; Johnson, Steven T.

    2014-01-01

    This research examined the changes in inflammatory cytokines interleukin 6 (IL-6), IL-1ß, 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 eccentric exercise results in DOMS but does not produce a sustained systemic inflammatory reaction or changes in muscle function. PMID:24809007

  2. 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.

  3. Effect of eccentric versus concentric exercise training on mitochondrial function.

    Science.gov (United States)

    Isner-Horobeti, Marie-Eve; Rasseneur, Laurence; Lonsdorfer-Wolf, Evelyne; Dufour, Stéphane Pascal; Doutreleau, Stéphane; Bouitbir, Jamal; Zoll, Joffrey; Kapchinsky, Sophia; Geny, Bernard; Daussin, Frédéric Nicolas; Burelle, Yan; Richard, Ruddy

    2014-11-01

    The effect of eccentric (ECC) versus concentric (CON) training on metabolic properties in skeletal muscle is understood poorly. We determined the responses in oxidative capacity and mitochondrial H2 O2 production after eccentric (ECC) versus concentric (CON) training performed at similar mechanical power. Forty-eight rats performed 5- or 20-day eccentric (ECC) or concentric (CON) training programs. Mitochondrial respiration, H2 O2 production, citrate synthase activity (CS), and skeletal muscle damage were assessed in gastrocnemius (GAS), soleus (SOL) and vastus intermedius (VI) muscles. Maximal mitochondrial respiration improved only after 20 days of concentric (CON) training in GAS and SOL. H2 O2 production increased specifically after 20 days of eccentric ECC training in VI. Skeletal muscle damage occurred transiently in VI after 5 days of ECC training. Twenty days of ECC versus CON training performed at similar mechanical power output do not increase skeletal muscle oxidative capacities, but it elevates mitochondrial H2 O2 production in VI, presumably linked to transient muscle damage. © 2014 Wiley Periodicals, Inc.

  4. 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

  5. Eccentric exercise in adults with cardiorespiratory disease: a systematic review.

    Science.gov (United States)

    Ellis, Rachel; Shields, Nora; Lim, Kwang; Dodd, Karen J

    2015-12-01

    To determine if eccentric exercise is effective, tolerable and safe for adults with chronic cardiorespiratory disease. We searched electronic databases from inception until January 2015 (Medline, CINAHL, Embase, SportDiscus, PEDro, Cochrane Central and AMED) supplemented by citation tracking and reference list scanning. Included articles had to report effects of eccentric exercise, alone or as a primary component of intervention, of any intensity and duration, on adults with chronic cardiorespiratory disease. Trials needed to be reported as full text in a peer-reviewed journal and include control data (randomised, quasi-randomised and single group cross-over design trials). Any outcomes or comparison interventions were accepted. Methodological rigor was assessed using the PEDro scale. Of 22 potentially relevant articles, 10 met inclusion criteria. They reported results from seven trials with a total of 112 participants across the diseases. PEDro scores were low (median 3). Eccentric exercise increased strength and mobility to comparable levels as concentric exercise, however, it did so with lower oxygen consumption (effect size as large as d = -3.07 (-4.12, -1.80)), and four-fold power output (effect size d = -3.60 (-5.03, -1.66)). There were no adverse events reported for eccentric exercise. Pain was avoided with familiarisation sessions and individual exercise prescription. Eccentric exercise is beneficial and at least comparable with traditional exercise in improving walking and strength for people with chronic cardiorespiratory disease. It was well tolerated and we identified no safety concerns for the use of this intervention for this population. © The Author(s) 2015.

  6. Acute hormonal responses following different velocities of eccentric exercise.

    Science.gov (United States)

    Libardi, Cleiton A; Nogueira, Felipe R D; Vechin, Felipe C; Conceição, Miguel S; Bonganha, Valéria; Chacon-Mikahil, Mara Patricia T

    2013-11-01

    The aim of this study was to compare the acute hormonal responses following two different eccentric exercise velocities. Seventeen healthy, untrained, young women were randomly placed into two groups to perform five sets of six maximal isokinetic eccentric actions at slow (30° s(-1) ) and fast (210° s(-1) ) velocities with 60-s rest between sets. Growth hormone, cortisol, free and total testosterone were assessed by blood samples collected at baseline, immediately postexercise, 5, 15 and 30 min following eccentric exercise. Changes in hormonal responses over time were compared between groups, using a mixed model followed by a Tukey's post hoc test. The main findings of the present study were that the slow group showed higher growth hormone values immediately (5·08 ± 2·85 ng ml(-1) , P = 0·011), 5 (5·54 ± 3·01 ng ml(-1) , P = 0·004) and 15 min (4·30 ± 2·87 ng ml(-1) , P = 0·021) posteccentric exercise compared with the fast group (1·39 ± 2·41 ng ml(-1) , 1·34 ± 1·97 ng ml(-1) and 1·24 ± 1·87 ng ml(-1) , respectively), and other hormonal responses were not different between groups (P>0·05). In conclusion, slow eccentric exercise velocity enhances more the growth hormone(GH) response than fast eccentric exercise velocity without cortisol and testosterone increases. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. Shedding Light on the Eccentricity Valley: Gap Heating and Eccentricity Excitation of Giant Planets in Protoplanetary Disks

    CERN Document Server

    Tsang, David; Cumming, Andrew

    2013-01-01

    We show that the first order (non co-orbital) corotation torques are significantly modified by entropy gradients in a non-barotropic protoplanetary disk. Such non-barotropic torques can dramatically alter the balance that, for barotropic cases, results in the net eccentricity damping for giant gap-clearing planets embedded in the disk. We demonstrate that stellar illumination can heat the gap enough for the planet's orbital eccentricity to instead be excited. We also discuss the "Eccentricity Valley" noted in the known exoplanet population, where low-metallicity stars have a deficit of eccentric planets between $\\sim 0.1$ and $\\sim 1$ AU compared to metal-rich systems (Dawson & Murray-Clay 2013). We show that this feature in the planet distribution may be due to the self-shadowing of the disk by a rim located at the dust sublimation radius $\\sim 0.1$ AU, which is known to exist for several T Tauri systems. In the shadowed region between $\\sim 0.1$ and $\\sim 1$ AU lack of gap insolation allows disk interac...

  8. Towards a general method for estimating the unbalanced magnetic pull in mixed eccentricities motion including sufficiently large eccentricities in a hydropower generator and their validation against EM simulations

    Science.gov (United States)

    Calleecharan, Yogeshwarsing; Jauregui, Ricardo; Aidanpää, Jan-Olov

    2013-08-01

    Electromagnetic (EM) analysis of hydropower generators is common practice but rotor whirling is little studied. This paper suggests a novel semi-analytical method for estimating the steady state unbalanced magnetic pull (UMP) when the rotor centre is undergoing mixed eccentricities motion. The ability to estimate the UMP for mixed eccentricities motion in finite element method (FEM)-based modelling software packages is rare. The proposed methodology in its formulation takes advantage of the fact that a purely dynamic eccentricity motion including non-synchronous whirling and a purely static eccentricity motion can be more amenable to implement in existing FEM-based EM modelling software products for UMP estimation. After these initial separate UMP results are obtained, the proposed method can be applied for virtually any mixed eccentricities motion cases up to sufficiently large eccentricities for quick analysis instead of running the mixed eccentricities simulations directly in a FEM-based software package. Good agreement between the UMP from the actual EM mixed eccentricities motion simulations in a commercial FEM-based software package and the UMP estimations by the novel method is made for a wide range of eccentricities that may commonly occur in practice. A modified feature selective validation (FSV) method, the FSV-UPC, is applied to assess the similarities and the differences in the UMP computations.

  9. Origin and Implications of high eccentricities in massive black hole binaries at sub-pc scales

    CERN Document Server

    Roedig, Constanze

    2011-01-01

    We outline the eccentricity evolution of sub-parsec massive black hole binaries (MBHBs) forming in galaxy mergers. In both stellar and gaseous environments, MBHBs are expected to grow large orbital eccentricities before they enter the gravitational wave (GW) observational domain. We re--visit the predicted eccentricities detectable by space based laser interferometers (as the proposed ELISA/NGO) for both environments. Close to coalescence, many MBHBs will still maintain detectable eccentricities, spanning a broad range from <10^{-5} up to <~ 0.5. Stellar and gas driven dynamics lead to distinct distributions, with the latter favoring larger eccentricities. At larger binary separations, when emitted GWs will be observed by pulsar timing arrays (PTAs), the expected eccentricities are usually quite large, in the range 0.01-0.7, which poses an important issue for signal modelling and detection algorithms. In this window, large eccentricities also have implications on proposed electromagnetic counterparts to...

  10. 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.

  11. 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; 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, Ismael; Deneva, Julia S.; Faucher-Giguere, Claude-Andre; Gaensler, Bryan M.; Han, JinLin; Jenet, Fredrick A.; Kasian, Laura

    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.

  12. The Eccentric Binary Millisecond Pulsar in NGC 1851

    CERN Document Server

    Freire, Paulo C C; Gupta, Yashwant

    2007-01-01

    PSR J0514-4002A is a 5-ms pulsar is located in the globular cluster NGC 1851; it belongs to a highly eccentric (e = 0.888) binary system. It is one of the earliest known examples of a numerous and fast-growing class of eccentric binary MSPs recently discovered in globular clusters. Using the GBT, we have obtained a phase-coherent timing solution for the pulsar, which includes a measurement of the rate of advance of periastron: 0.01289(4) degrees per year, which if due completely to general relativity, implies a total system mass of 2.453(14) solar masses. We also derive m_p 0.96 solar masses. The companion is likely to be a massive white dwarf star.

  13. 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.

  14. Chaos in the Test Particle Eccentric Kozai-Lidov Mechanism

    CERN Document Server

    Li, Gongjie; Holman, Matt; Loeb, Abraham

    2014-01-01

    The Kozai-Lidov mechanism can be applied to a vast variety of astrophysical systems involving hierarchical three-body systems. Here, we study the Kozai-Lidov mechanism systematically in the test particle limit at the octupole level of approximation. We investigate the chaotic and quasiperiodic orbital evolution by studying surfaces of section and the Lyapunov exponents. We find that the resonances introduced by the octupole level of approximation cause orbits to flip from prograde to retrograde and back as well as cause significant eccentricity excitation, and the chaotic behaviors occur when the mutual inclination between the inner and the outer binary is high. We characterize the parameter space that allows large amplitude oscillations in eccentricity and inclination.

  15. Chaos in the test particle eccentric Kozai-Lidov mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gongjie; Naoz, Smadar; Holman, Matt; Loeb, Abraham, E-mail: gli@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-08-20

    The Kozai-Lidov mechanism can be applied to a vast variety of astrophysical systems involving hierarchical three-body systems. Here, we study the Kozai-Lidov mechanism systematically in the test particle limit at the octupole level of approximation. We investigate the chaotic and quasi-periodic orbital evolution by studying the surfaces of section and the Lyapunov exponents. We find that the resonances introduced by the octupole level of approximation cause orbits to flip from prograde to retrograde and back as well as cause significant eccentricity excitation, and chaotic behavior occurs when the mutual inclination between the inner and the outer binary is high. We characterize the parameter space that allows large amplitude oscillations in eccentricity and inclination.

  16. Biomechanical characteristics of the eccentric Achilles tendon exercise

    DEFF Research Database (Denmark)

    Henriksen, Marius; Aaboe, Jens; Bliddal, Henning

    2009-01-01

    muscles were recorded. Joint kinematics, GRF frequency contents, average EMG amplitudes, and Achilles tendon loads were calculated. FINDINGS: The eccentric movement phase was characterized by a higher GRF frequency content in the 8-12 Hz range, and reduced EMG activity in the lower leg muscles...... 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...

  17. Effects of antioxidant therapy in women exposed to eccentric exercise.

    Science.gov (United States)

    Bloomer, Richard J; Goldfarb, Alan H; McKenzie, Michael J; You, Tonjian; Nguyen, Linh

    2004-08-01

    The purpose of this study was to determine the effects of antioxidant therapy on indirect markers of muscle damage following eccentric exercise (EE). Eighteen women were randomized to an antioxidant supplement or a placebo before a bout of EE. Plasma creatine kinase (CK) activity, muscle soreness (MS), maximal isometric force (MIF), and range of motion (ROM) were assessed before and through 14 d postexercise. Eccentric exercise resulted in an increase in CK activity and MS, and a drop in MIF and ROM during the days following EE, which returned to baseline values 14 d after EE in both groups. Antioxidants attenuated the CK activity and MS response to the EE, while little difference was noted between groups in MIF or ROM. These findings suggest that antioxidant supplementation was helpful in reducing the elevations in plasma CK activity and MS, with little impact on MIF and ROM loss.

  18. Spectrum of 100-kyr glacial cycle: orbital inclination, not eccentricity.

    Science.gov (United States)

    Muller, R A; MacDonald, G J

    1997-08-05

    Spectral analysis of climate data shows a strong narrow peak with period approximately 100 kyr, attributed by the Milankovitch theory to changes in the eccentricity of the earth's orbit. The narrowness of the peak does suggest an astronomical origin; however the shape of the peak is incompatible with both linear and nonlinear models that attribute the cycle to eccentricity or (equivalently) to the envelope of the precession. In contrast, the orbital inclination parameter gives a good match to both the spectrum and bispectrum of the climate data. Extraterrestrial accretion from meteoroids or interplanetary dust is proposed as a mechanism that could link inclination to climate, and experimental tests are described that could prove or disprove this hypothesis.

  19. An Eccentric Binary Millisecond Pulsar in the Galactic Plane

    CERN Document Server

    Champion, D J; Lazarus, P; Camilo, F; Bassa, C; Kaspi, V M; Nice, D J; Freire, P C C; Stairs, I H; Van Leeuwen, J; Stappers, B W; Cordes, J M; Hessels, J W T; Lorimer, D R; Arzoumanian, Z; Backer, D C; Bhat, N D R; Chatterjee, S; Cognard, I; Deneva, J S; Faucher-Giguere, C -A; Gaensler, B M; Han, J L; Jenet, F A; Kasian, L; Kondratiev, V I; Krämer, M; Lazio, J; McLaughlin, M A; Venkataraman, A; Vlemmings, W

    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 ms in a highly eccentric (e = 0.44) 95-day orbit around a solar mass 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 Msun, an unusually high value.

  20. 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.

  1. Eccentric Pumping Unit: Cost-effective and Reliable

    Institute of Scientific and Technical Information of China (English)

    Zhang Shaobo; Gao Heping; Chen Yibao; Shi Linsong; Zhang Huiwen

    1996-01-01

    @@ The beam-type pumping unit is the most widely used ty pe of pumping unit because of its simple geometry and its reliability. However. when its stroke exceeds five meters, the structure of the unit becomes massive and its cost becomes quite high. In order to make full use of the advantages of the beam pumping unit and to enhance its stroke. a new type of pumping unit - the ECCENTRIC PUMPING UNIT - has been designed after two years of the research work.

  2. 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.

  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. Revisiting the Force-Joint Angle Relationship After Eccentric Exercise.

    Science.gov (United States)

    Welsh, Molly C; Allen, David L; Batliner, Matthew E; Byrnes, William C

    2015-12-01

    The purpose of this study was to evaluate force-angle curve fitting techniques pre-eccentric exercise, quantify changes in curve characteristics postexercise, and examine the relationship between curve changes and markers of muscle damage. Fourteen males unaccustomed to eccentric exercise performed 60 eccentric muscle actions of the elbow flexors. Maximal voluntary isometric force was measured throughout a range of angles pre- (Pre1 and Pre2), immediately post (IP), and 1, 2, 4, and 7 days postexercise. Force-angle curves for each visit were constructed using second-order polynomials. Changes in curve characteristics (optimal angle, peak force, curve height), range of motion, soreness, and creatine kinase activity were quantified. Optimal joint angle and force at optimal angle were significantly correlated from Pre1 to Pre2 (ICC = 0.821 and 0.979, respectively). Optimal angle was significantly right shifted (p = 0.035) by 10.4 ± 12.9° from Pre2 to IP and was restored by 1 day post exercise. Interestingly, the r value for curve fit was significantly decreased (p exercise (r = 0.750). Curve height was significantly decreased (39%) IP and restored to pre-exercise height by 4 days postexercise. There was no correlation between optimal angle or curve height and other damage markers. In conclusion, force-angle relationships can be accurately described using second-order polynomials. After eccentric exercise, the force-angle curve is flattened and shifted (downward and rightward), but these changes are not correlated to other markers of muscle damage. Changes in the force-angle relationship are multifaceted, but determining the physiological significance of these changes requires further investigation.

  5. 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 (pexercise. After 24h, 48h and 72h, CK was increased in ECC compared to IPC+ECC (between groups: 24h: p=0.004, 48h: pexercise, when compared to IPC+ECC (between groups: all pexercise days in ECC (all peccentric exercise of the elbow flexors blunts EIMD and exercise-induced pain, while maintaining the contractile properties of the muscle.

  6. Transition from inspiral to plunge for eccentric equatorial Kerr orbits

    CERN Document Server

    O'Shaughnessy, R

    2003-01-01

    Ori and Thorne have discussed the duration and observability (with LISA) of the transition from circular, equatorial inspiral to plunge for stellar-mass objects into supermassive ($10^{5}-10^{8}M_{\\odot}$) Kerr black holes. We extend their computation to eccentric Kerr equatorial orbits. Even with orbital parameters near-exactly determined, we find that there is no universal length for the transition; rather, the length of the transition depends sensitively -- essentially randomly -- on initial conditions. Still, Ori and Thorne's zero-eccentricity results are essentially an upper bound on the length of eccentric transitions involving similar bodies (e.g., $a$ fixed). Hence the implications for observations are no better: if the massive body is $M=10^{6}M_{\\odot}$, the captured body has mass $m$, and the process occurs at distance $d$ from LISA, then $S/N \\lesssim (m/10 M_{\\odot})(1\\text{Gpc}/d)\\times O(1)$, with the precise constant depending on the black hole spin. For low-mass bodies ($m \\lesssim 7 M_\\odot$...

  7. Evidence for Reflected Light from the Most Eccentric Exoplanet Known

    CERN Document Server

    Kane, Stephen R; Hinkel, Natalie R; Roy, Arpita; Mahadevan, Suvrath; Dragomir, Diana; Matthews, Jaymie M; Henry, Gregory W; Chakraborty, Abhijit; Boyajian, Tabetha S; Wright, Jason T; Ciardi, David R; Fischer, Debra A; Butler, R Paul; Tinney, C G; Carter, Brad D; Jones, Hugh R A; Bailey, Jeremy; O'Toole, Simon J

    2015-01-01

    Planets in highly eccentric orbits form a class of objects not seen within our Solar System. The most extreme case known amongst these objects is the planet orbiting HD 20782, with an orbital period of 597 days and an eccentricity of 0.96. Here we present new data and analysis for this system as part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS). We obtained CHIRON spectra to perform an independent estimation of the fundamental stellar parameters. New radial velocities from AAT and PARAS observations during periastron passage greatly improve the our knowledge of the eccentric nature of the orbit. The combined analysis of our Keplerian orbital and Hipparcos astrometry show that the inclination of the planetary orbit is > 1.25 degrees, ruling out stellar masses for the companion. Our long-term robotic photometry show that the star is extremely stable over long timescales. Photometric monitoring of the star during predicted transit and periastron times using MOST rule out a transit of the pla...

  8. [The recovery of visual performance in strabismus with eccentric fixation].

    Science.gov (United States)

    Rusu, V

    1997-01-01

    The purpose of this work is to realise a general view about the diagnosis, therapeutic methods and the results obtained in eccentric fixation strabismus. We realised a six years retrospective study on 144 eccentric strabismus, watching dynamic the evolution by testing: the orthophoric status, visual acuity, binocular vision and the type of fixation. Medium follow un time was of 19.6 months. In the end of the treatment we notice: visual acuity between 0.1-0.5 in 14% cases; central fixation in 52 children (36%); first degree of binocular vision in 15 children (10.4%) and second degree in 5 cases (3.47%). This study showed that the early installation of eccentric fixation strabismus was in 53% cases before reaching one year old and in 90% before two years old. The functional results was negative influenced by the delay in presentation (42% come after 2 years) and the difficulties in family cooperation (46.5% were followed up lesenban 6 months).

  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. Orbital Eccentricity Distribution of Solar-Neighbour Halo Stars

    CERN Document Server

    Hattori, Kohei

    2011-01-01

    We present theoretical calculations for the differential distribution of stellar orbital eccentricity for a sample of solar-neighbour 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-neighbour eccentricity distribution \\Delta N(e) is then formulated, based on a static distribution function of the form f(E,L) in which the velocity anisotropy parameter \\beta monotonically increases in the radial direction away from the galaxy center, such that beta is below unity (near isotropic velocity dispersion) in the central region and asymptotically approaches \\sim 1 (radially anisotropic velocity dispersion) in the far distant region of the halo. We find that \\Delta N(e) sensitively depends upon the radial profile of \\beta, and this sensitivit...

  11. Nonlinear dynamics in eccentric Taylor-Couette-Poiseuille flow

    Science.gov (United States)

    Pier, Benoît; Caulfield, C. P.

    2015-11-01

    The flow in the gap between two parallel but eccentric cylinders and driven by an axial pressure gradient and inner cylinder rotation is characterized by two geometrical parameters (radius ratio and eccentricity) and two dynamic parameters (axial and azimuthal Reynolds numbers). Such a theoretical configuration is a model for the flow between drill string and wellbore in the hydrocarbon drilling industry. The linear convective and absolute instability properties have been systematically derived in a recent study [Leclercq, Pier & Scott, J. Fluid Mech. 2013 and 2014]. Here we address the nonlinear dynamics resulting after saturation of exponentially growing small-amplitude perturbations. By using direct numerical simulations, a range of finite-amplitude states are found and characterized: nonlinear traveling waves (an eccentric counterpart of Taylor vortices, associated with constant hydrodynamic loading on the inner cylinder), modulated nonlinear waves (with time-periodic torque and flow rate) and more irregular states. In the nonlinear regime, the hydrodynamic forces are found to depart significantly from those prevailing for the base flow, even in situations of weak linear instability.

  12. Plasma Actin, Gelsolin and Orosomucoid Levels after Eccentric Exercise.

    Science.gov (United States)

    Tékus, Éva; Váczi, Márk; Horváth-Szalai, Zoltán; Ludány, Andrea; Kőszegi, Tamás; Wilhelm, Márta

    2017-02-01

    The present study investigated the acute effect of eccentric exercise on blood plasma actin, gelsolin (GSN) and orosomucoid (AGP) levels in untrained and moderately trained individuals, and their correlation with exercise induced muscle damage (EIMD) markers (CK, intensity of muscle soreness and maximal voluntary contraction torque deficit). Healthy physical education students (6 untrained, 12 moderately trained) participated in this research. Actin, GSN, AGP and CK levels were measured in blood plasma at baseline, immediately, 1 h, 6 h and 24 h post-exercise comprising 90 eccentric quadriceps contractions performed on a dynamometer. There was significant time main effect for GSN, AGP, CK and significant difference was found between baseline and the lowest value of post-exercise GSN (p exercise AGP (p exercise and CK activity at 6 h, p exercise, p eccentric exercise do not seem sensitive to training status. The plasma actin level is used as an indicator of injury, however, our results suggest that it is not an accurate marker of EIMD, while plasma GSN concentrations show a better relationship with EIMD and the post-exercise inflammatory process. The elevated plasma AGP and the correlation between GSN and AGP seem to be promising for assessment of exercise-induced muscle injury.

  13. Heartbeat Stars: A Class Of Tidally Excited Eccentric Binaries

    Science.gov (United States)

    Barclay, Thomas; Thompson, S. E.; Mullally, F.; Everett, M.; Howell, S. B.; Still, M.; Christiansen, J. L.; Rowe, J.; Kurtz, D. W.; Hambleton, K.

    2012-01-01

    We have discovered a class of eccentric binary systems undergoing dynamic tidal distortions and tidally induced pulsations in the Kepler data. Each has a uniquely shaped light curve that is characterized by periodic brightening or variability at time scales of 4-20 days which is frequently accompanied by shorter period oscillations. We can explain the dominant features of the entire class with changing tidal forces that occur in close, eccentric binary systems. In this case the large variety of light curve shapes arises from viewing systems at different angles. A hypothesis that is confirmed with radial velocity measurements that show an eccentric orbit. Prior to the discovery of these 17 new systems, KOI-54 was the only system with direct detection of these dynamic tides and tidally induced oscillations. While significant work remains to include all the physics required to accurately model these systems and begin to understand how tidal effects influence the system, in this presentation we present preliminary fits to the light curves and describe the properties of this class of stars as a whole.

  14. A simple model of the chaotic eccentricity of Mercury

    CERN Document Server

    Boué, Gwenaël; Farago, François

    2012-01-01

    Mercury's eccentricity is chaotic and can increase so much that collisions with Venus or the Sun become possible (Laskar, 1989, 1990, 1994, 2008, Batygin & Laughlin, 2008, Laskar & Gastineau, 2009). This chaotic behavior results from an intricate network of secular resonances, but in this paper, we show that a simple integrable model with only one degree of freedom is actually able to reproduce the large variations in Mercury's eccentricity, with the correct amplitude and timescale. We show that this behavior occurs in the vicinity of the separatrices of the resonance g1-g5 between the precession frequencies of Mercury and Jupiter. However, the main contribution does not come from the direct interaction between these two planets. It is due to the excitation of Venus' orbit at Jupiter's precession frequency g5. We use a multipolar model that is not expanded with respect to Mercury's eccentricity, but because of the proximity of Mercury and Venus, the Hamiltonian is expanded up to order 20 and more in t...

  15. 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=<0.001). Arterial stiffness similarly peaked at 48 h (p=0.04) and remained significantly elevated above baseline through 72 h. Eccentrically accentuated downhill 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.

  16. Exploring a Stream of Highly-Eccentric Binaries with Kepler

    CERN Document Server

    Dong, Subo; Socrates, Aristotle

    2012-01-01

    With 16-month Kepler data, 14 long-period (40 d - 265 d) eclipsing binaries on highly eccentric orbits (minimum e between 0.5 and 0.85) are recognized from their closely separated primary and secondary eclipses (\\Delta t_I,II = 3 d - 10 d). These systems confirm the existence of a previously hinted binary population situated near a constant angular momentum track at P(1-e^2)^(3/2) ~ 15 d, close to the tidal circularization period P_circ. They may be presently migrating due to tidal dissipation and form a steady-state stream (~1% of stars) feeding the close-binary population (few percent of stars). If so, future Kepler data releases will reveal a growing number (dozens) of systems at longer periods, following dN/dlgP \\propto P^(1/3) with increasing eccentricities reaching e -> 0.98 for P -> 1000d. 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 "eccentric...

  17. Evidence for Reflected Light from the Most Eccentric Exoplanet Known

    Science.gov (United States)

    Kane, Stephen R.; Wittenmyer, Robert A.; Hinkel, Natalie R.; Roy, Arpita; Mahadevan, Suvrath; Dragomir, Diana; Matthews, Jaymie M.; Henry, Gregory W.; Chakraborty, Abhijit; Boyajian, Tabetha S.; Wright, Jason T.; Ciardi, David R.; Fischer, Debra A.; Butler, R. Paul; Tinney, C. G.; Carter, Brad D.; Jones, Hugh R. A.; Bailey, Jeremy; O'Toole, Simon J.

    2016-04-01

    Planets in highly eccentric orbits form a class of objects not seen within our solar system. The most extreme case known among these objects is the planet orbiting HD 20782, with an orbital period of 597 days and an eccentricity of 0.96. Here we present new data and analysis for this system as part of the Transit Ephemeris Refinement and Monitoring Survey. We obtained CHIRON spectra to perform an independent estimation of the fundamental stellar parameters. New radial velocities from Anglo-Australian Telescope and PARAS observations during periastron passage greatly improve our knowledge of the eccentric nature of the orbit. The combined analysis of our Keplerian orbital and Hipparcos astrometry show that the inclination of the planetary orbit is \\gt 1\\_\\_AMP\\_\\_fdg;22, ruling out stellar masses for the companion. Our long-term robotic photometry show that the star is extremely stable over long timescales. Photometric monitoring of the star during predicted transit and periastron times using Microvariability and Oscillations of STars rule out a transit of the planet and reveal evidence of phase variations during periastron. These possible photometric phase variations may be caused by reflected light from the planet’s atmosphere and the dramatic change in star-planet separation surrounding the periastron passage.

  18. Pure eccentric exercise does not activate blood coagulation.

    Science.gov (United States)

    Hilberg, Thomas; Gläser, Doreen; Prasa, Dagmar; Stürzebecher, Jörg; Gabriel, Holger H W

    2005-08-01

    Eccentric exercise can cause skeletal muscle damage with ultrastructural disruption, inflammation and increased proteolytic enzyme activity. It may be possible that these changes are able to trigger blood coagulation in vivo. The aim of the study was to investigate changes in blood coagulation via the measurement of aPTT, the thrombin potential (total [TTP] and endogenous [ETP], both intrinsic [in] and extrinsic [ex]) and the thrombin generation (prothrombinfragment 1 + 2 [F1 + 2] and thrombin-antithrombin complex [TAT]) after pure eccentric exercise. Seventeen healthy non-smokers (28 +/- 6 years, VO2-peak 59 +/- 7 ml/min/kg) underwent pure eccentric down jumps (9 x 28 isolated down jumps in 90 min, drop from a height of 55 cm), a cycle exercise (90% of the individual anaerobic threshold for 60-90 min) and a control experiment on different days. Blood samples were drawn after a 30-min rest, immediately, and 2 h after exercise. After the cycle exercise, a clear shortening by 12% (Pcoagulation.

  19. Behavior of high strength concrete columns under eccentric loads

    Directory of Open Access Journals (Sweden)

    Hany A. Kottb

    2015-04-01

    Full Text Available In recent decades, high strength concrete (HSC has been widely accepted by designers and contractors to be used in concrete structures, especially in high compressive stress elements. The research aims to study the behavior of high strength concrete columns under eccentric compression using experimental and analytical programs. The research is divided into two main parts; the first part is an experimental investigation for ten square columns tested at the Cairo University Concrete Research Laboratory. The main studied parameters were eccentricity of the applied load, column slenderness ratio; and ratios of longitudinal and transverse reinforcement. The second part is analytical analysis using nonlinear finite element program ANSYS11 on nineteen columns (ten tested square columns and nine rectangular section columns to study the effect of the previous parameters on the column ultimate load, mid-height displacement, and column cracking patterns. The analyzed columns revealed a good agreement with the experimental results with an average difference of 16% and 17% for column ultimate load and mid-height displacement respectively. Results showed an excellent agreement for cracking patterns. Predictions of columns capacities using the interaction diagrams based on ACI 318-08 stress block parameters indicated a safe design procedure of HSC columns under eccentric compression, with ACI 318-08 being more conservative for moderate reinforced HSC columns.

  20. Dynamics of prolate spheroidal mass distributions with varying eccentricity

    CERN Document Server

    Rathulnath, R

    2013-01-01

    In this paper we calculate the potential for a prolate spheroidal distribution as in a dark matter halo with a radially varying eccentricity. This is obtained by summing up the shell-by-shell contributions of isodensity surfaces, which are taken to be concentric and with a common polar axis and with an axis ratio that varies with radius. Interestingly, the constancy of potential inside a shell is shown to be a good approximation even when the isodensity contours are dissimilar spheroids, as long as the radial variation in eccentricity is small as seen in realistic systems. We consider three cases where the isodensity contours are more prolate at large radii, or are less prolate, or have a constant eccentricity. Other relevant physical quantities like the rotation velocity, the net orbital and vertical frequency due to the halo and an exponential disc of finite thickness embedded in it are obtained. We apply this to the kinematical origin of Galactic warp, and show that a prolate shaped halo is not conducive t...

  1. Predictions for a planet just inside Fomalhaut's eccentric ring

    CERN Document Server

    Quillen, A C

    2006-01-01

    We propose that the eccentricity and sharpness of the edge of Fomalhaut's disk are due to a planet just interior to the ring edge. The collision timescale consistent with the disk opacity is long enough that spiral density waves cannot be driven near the planet. The ring edge is likely to be located at the boundary of a chaotic zone in the corotation region of the planet. We find that this zone can open a gap in a particle disk as long as the collision timescale exceeds the removal or ejection timescale in the zone. We use the slope measured from the ring edge surface brightness profile to place an upper limit on the planet mass. The removal timescale in the chaotic zone is used to estimate a lower limit on the planet mass. The ring edge has eccentricity caused by by secular perturbations from the planet. These arguments imply that the planet has a mass between that of Neptune and that of Saturn, a semi-major axis of approximately 119 AU and longitude of periastron and eccentricity, 0.1, the same as that of t...

  2. Dynamics of Neptune's Trojans: II. Eccentric orbits and observed ones

    CERN Document Server

    Zhou, Li-Yong; Sun, Yi-Sui

    2010-01-01

    In a previous paper, we have presented a global view of the stability of Neptune Trojan (NT hereafter) on inclined orbit. We discuss in this paper the dependence of stability of NT orbits on the eccentricity. High-resolution dynamical maps are constructed using the results of extensive numerical integrations of orbits initialized on the fine grids of initial semimajor axis (a0) versus eccentricity (e0). The extensions of regions of stable orbits on the (a0, e0) plane at different inclinations are shown. The maximum eccentricities of stable orbits in three most stable regions at low (0, 12deg.), medium (22,36deg.) and high (51, 59deg.) inclination, are found to be 0.10, 0.12 and 0.04, respectively. The fine structures in the dynamical maps are described. Via the frequency analysis method, the mechanisms that portray the dynamical maps are revealed. The secondary resonances, concerning the frequency of the librating resonant angle and the frequency of the quasi 2:1 mean motion resonance between Neptune and Uran...

  3. A Simple Family of Models for Eccentric Keplerian Fluid Disks

    CERN Document Server

    Statler, T S

    2001-01-01

    In order to be in a long-lived configuration, the density in a fluid disk should be constant along streamlines to prevent compressional (PdV) work from being done cyclically around every orbit. In a pure Kepler potential, flow along aligned, elliptical streamlines of constant eccentricity will satisfy this condition. For most density profiles, differential precession driven by the pressure gradient will destroy the alignment; however, in the razor-thin approximation there is a family of simple equilibria in which the precession frequency is the same at all radii. These disks may therefore be long-lived at significant eccentricities. The density can be made axisymmetric as r goes to 0, while maintaining the precession rate, by relaxing the requirement of constancy along streamlines in an arbitrarily small transition region near the center. In the limit of small eccentricity, the models can be seen as acoustically perturbed axisymmetric disks, and the precession rate is shown to agree with linear theory. The pe...

  4. Eccentric exercise: mechanisms and effects when used as training regime or training adjunct.

    Science.gov (United States)

    Vogt, Michael; Hoppeler, Hans H

    2014-06-01

    The aim of the current review is to discuss applications and mechanism of eccentric exercise in training regimes of competitive sports. Eccentric muscle work is important in most sports. Eccentric muscle contractions enhance the performance during the concentric phase of stretch-shortening cycles, which is important in disciplines like sprinting, jumping, throwing, and running. Muscles activated during lengthening movements can also function as shock absorbers, to decelerate during landing tasks or to precisely deal with high external loading in sports like alpine skiing. The few studies available on trained subjects reveal that eccentric training can further enhance maximal muscle strength and power. It can further optimize muscle length for maximal tension development at a greater degree of extension, and has potential to improve muscle coordination during eccentric tasks. In skeletal muscles, these functional adaptations are based on increases in muscle mass, fascicle length, number of sarcomeres, and cross-sectional area of type II fibers. Identified modalities for eccentric loading in athletic populations involve classical isotonic exercises, accentuated jumping exercises, eccentric overloading exercises, and eccentric cycle ergometry. We conclude that eccentric exercise offers a promising training modality to enhance performance and to prevent injuries in athletes. However, further research is necessary to better understand how the neuromuscular system adapts to eccentric loading in athletes. Copyright © 2014 the American Physiological Society.

  5. Multi-Beam Interference Transmission Spectrum Observed from an Eccentric Core Single-Mode Fiber

    Institute of Scientific and Technical Information of China (English)

    FAN Un-Yong; JIANG Wei-Wei; ZHAO Rui-Feng; PEI Li; JIAN Shui-Sheng

    2011-01-01

    @@ An eccentric core single-mode fiber, whose core is away from the axis of the fiber, is fabricated by using the fiber preform goniometric-groove method and the stack-and-draw method.An eccentric core single-mode fiber without coating is spliced between two single-mode fibers.Fundamental mode and cladding modes are excited at one splicing point between the eccentric core single-mode fiber and the single-mode fiber, and propagate in the eccentric core single-mode fiber, then interfere with each other at the other splicing point.Multi-beam interference transmission spectrum is observed.An in-line fiber interferometric strain sensor based on the eccentric core single-mode fiber is realized.%An eccentric core single-mode fiber, whose core is away from the axis of the fiber, is fabricated by using the fiber preform goniometric-groove method and the stack-and-draw method. An eccentric core single-mode fiber without coating is spliced between two single-mode fibers. Fundamental mode and cladding modes are excited at one splicing point between the eccentric core single-mode fiber and the single-mode fiber, and propagate in the eccentric core single-mode fiber, then interfere with each other at the other splicing point. Multi-beam interference transmission spectrum is observed. An in-line fiber interferometric strain sensor based on the eccentric core single-mode fiber is realized.

  6. 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

  7. Lengthening our perspective: morphological, cellular, and molecular responses to eccentric exercise.

    Science.gov (United States)

    Hyldahl, Robert D; Hubal, Monica J

    2014-02-01

    The response of skeletal muscle to unaccustomed eccentric exercise has been studied widely, yet it is incompletely understood. This review is intended to provide an up-to-date overview of our understanding of how skeletal muscle responds to eccentric actions, with particular emphasis on the underlying molecular and cellular mechanisms of damage and recovery. This review begins by addressing the question of whether eccentric actions result in physical damage to muscle fibers and/or connective tissue. We next review the symptomatic manifestations of eccentric exercise (i.e., indirect damage markers, such as delayed onset muscle soreness), with emphasis on their relatively poorly understood molecular underpinnings. We then highlight factors that potentially modify the muscle damage response following eccentric exercise. Finally, we explore the utility of using eccentric training to improve muscle function in populations of healthy and aging individuals, as well as those living with neuromuscular disorders. Copyright © 2013 Wiley Periodicals, Inc.

  8. Effect of eccentricity on junction and junctionless based silicon nanowire and silicon nanotube FETs

    Science.gov (United States)

    Scarlet, S. Priscilla; Ambika, R.; Srinivasan, R.

    2017-07-01

    In this paper, the effect of eccentricity on Junction-based Silicon Nanowire FET, Junction-based Silicon Nanotube FET, Junctionless-based Silicon Nanowire FET, and Junctionless-based Silicon Nanotube FET is investigated. Three kinds of eccentric structures are considered here. The impact of eccentricity on effective gate oxide thickness thereby gate oxide capacitance, and effective channel width are studied using 3D numerical simulations. Average radius of an ellipse is used to generate a model which captures the impact of eccentricity on gate oxide capacitance, and verified using TCAD simulations in MOS nanowire structure. The impact of eccentricity on ON current (ION), OFF current (IOFF), ION/IOFF ratio, and Unity gain cutoff frequency are investigated. Eccentricity increases the effective gate oxide thickness, the effective channel width, ION, and IOFF but reduces ION/IOFF ratio.

  9. 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.

  10. Effects of Eccentricity on the Dynamic Behavior for Electromechanical Integrated Toroidal Drive

    Directory of Open Access Journals (Sweden)

    Lizhong Xu

    2013-01-01

    Full Text Available In electromechanical integrated toroidal drive, eccentric center errors occur which has important influences on the dynamic behavior of the drive system. Here, the dynamic equations of the drive system with eccentric center are presented. Changes of the natural frequencies and vibrating modes along with eccentric center distance are analyzed. The forced responses of the drive system to eccentric center excitation are investigated. Results show that the eccentric center causes some natural frequencies to increase, and the other natural frequencies to drop. It also causes some vibrations to become weak, and the other vibrations to become strong. The eccentric center has more obvious effects on the dynamic behavior of the planets. The results are useful in design and manufacture of the drive systems.

  11. Strength gain through eccentric isotonic training without changes in clinical signs or blood markers

    OpenAIRE

    Alves, Thamara [UNESP; Guarnier, Flavia A.; Campoy,Fernanda A. S.; Gois, Mariana O.; Albuquerque, Maira C. [UNESP; Seraphim, Patricia M.; Netto Junior, Jayme; Marques Vanderlei, Luiz Carlos; Padovani, Carlos R; Cecchini, Rubens; Pastre, Carlos Marcelo

    2013-01-01

    Background Localized exercises are widely used in rehabilitation processes. The predominant options are exercises with an emphasis on either concentric or eccentric contractions. Eccentric exercises promote greater strength gains compared to classical concentric stimuli, but can cause muscle damage. The aim of present study was to compare strength training composed of 10 sessions with progressive loads between groups with a predominance of concentric versus eccentric contraction through an an...

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

    OpenAIRE

    Nosratollah Hedayatpour; Deborah Falla

    2015-01-01

    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 muscl...

  13. Measurement of Eccentricity of the Centre of Mass from the Geometric Centre of a Sphere

    Institute of Scientific and Technical Information of China (English)

    郭俊起; 胡忠坤; 顾邦明; 罗俊

    2004-01-01

    The eccentricity of the centre of mass from the geometric centre of a spherical attracting mass in determining the Newtonian gravitational constant G is tested by means of an electronic balance. The experimental result shows that the eccentricity of the sample is about 0.31 μm with uncertainty of 0.05 μm. Two density distribution models are discussed to estimate the uncertainty to G by the eccentricities of the attracting masses.

  14. An analysis of the expected eccentricity perturbations for the second Radio Astronomy Explorer (RAE B)

    Science.gov (United States)

    Murphy, J. P.

    1972-01-01

    Analytical prediction of expected eccentricity perturbations for the RAE 2 lunar orbit shows that the eccentricity will grow linearly in time. Parametric inclination studies and analysis of perturbation equations establish a critical retrograde inclination of 116.565 at which the positive perturbation slope vanishes for a circular orbit about 1100 m above the lunar surface with an eccentricity constraint of less than 0.005 during a period of about one year.

  15. The Akt-mTOR axis is a pivotal regulator of eccentric hypertrophy during volume overload

    OpenAIRE

    Masataka Ikeda; Tomomi Ide; Takeo Fujino; Yuka Matsuo; Shinobu Arai; Keita Saku; Takamori Kakino; Yasuhiro Oga; Akiko Nishizaki; Kenji Sunagawa

    2015-01-01

    The heart has two major modalities of hypertrophy in response to hemodynamic loads: concentric and eccentric hypertrophy caused by pressure and volume overload (VO), respectively. However, the molecular mechanism of eccentric hypertrophy remains poorly understood. Here we demonstrate that the Akt-mammalian target of rapamycin (mTOR) axis is a pivotal regulator of eccentric hypertrophy during VO. While mTOR in the heart was activated in a left ventricular end-diastolic pressure (LVEDP)-depende...

  16. Delayed onset of vastii muscle activity in response to rapid postural perturbations following eccentric exercise: a mechanism that underpins knee pain after eccentric exercise?

    Science.gov (United States)

    Hedayatpour, Nosratollah; Falla, Deborah

    2014-03-01

    Appropriate timing of activity of the vastus medialis obliqus (VMO) and vastus lateralis (VL) muscles is a key factor for proper tracking of the patella in the trochlear groove during knee extension. This study investigates the relative timing of activation of the VMO and VL muscles during unexpected perturbations performed before and after eccentric exercise. Surface electromyography signals were recorded from the VMO and VL muscles of the right leg in 11 healthy men during rapid postural perturbations performed at baseline, immediately after eccentric exercise of the quadriceps, and at 24 and 48 h after exercise. Participants stood on a moveable platform during which eight randomised postural perturbations were performed (4 repetitions of 2 perturbation types: 8 cm forward slides, 8 cm backward slides). Before the eccentric exercise, the onset of VMO activity was significantly earlier than the VL muscle (average for both forward and backward perturbations: VMO 39.0±7.1 ms; VL 43.7±7.9 ms). However, the onset of VMO activity was significantly later compared with VL muscle immediately after eccentric exercise and this remained 24 and 48 h after eccentric exercise (average across all postexercise sessions and perturbation directions: VMO 72.3±11.1 ms; VL 56.0±8.2 ms; peccentric exercise and during eccentric exercise-induced muscle soreness up to 48 h later. These observations may help explain the high prevalence of knee disorders after high intensity eccentric exercise.

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

    Science.gov (United States)

    Hedayatpour, Nosratollah; Falla, Deborah

    2015-01-01

    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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

    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 between eccentric muscle activation and muscle damage, particularly as it relates to running, and specifically, downhill running. PMID:7551767

  1. Neuromuscular Changes and Damage after Isoload versus Isokinetic Eccentric Exercise.

    Science.gov (United States)

    Doguet, Valentin; Nosaka, Kazunori; Plautard, Mathieu; Gross, Raphaël; Guilhem, GaËL; Guével, Arnaud; Jubeau, Marc

    2016-12-01

    This study compared the effects of isoload (IL) and isokinetic (IK) knee extensor eccentric exercises on changes in muscle damage and neuromuscular parameters to test the hypothesis that the changes would be different after IL and IK exercises. Twenty-two young men were paired based on their strength and placed in the IL (N = 11) or the IK (N = 11) group. The IL group performed 15 sets of 10 eccentric contractions with a 150% of predetermined one-repetition maximum load. The IK group performed 15 sets of several maximal eccentric contractions matched set by set for the total amount of work and mean angular velocity with the IL group. Muscle damage markers (voluntary isometric peak torque, muscle soreness, and creatine kinase activity) and neuromuscular variables (e.g., voluntary activation, H-reflex, M-wave, and evoked torque) were measured before, immediately after, and 24, 48, 72, and 96 h postexercise. Voluntary isometric peak torque decreased to the same extent (P = 0.94) in both groups immediately after (IL = -40.6% ± 13.8% vs IK = -42.4% ± 10.2%) to 96 h after the exercise (IL = -21.8% ± 28.5% vs IK = -26.7% ± 23.5%). Neither peak muscle soreness (IL = 48.1 ± 28.2 mm vs IK = 54.7 ± 28.9 mm, P = 0.57) nor creatine kinase activity (IL = 12,811 ± 22,654 U·L vs IK = 15,304 ± 24,739 U·L, P = 0.59) significantly differed between groups. H-reflex (IL = -23% vs IK = -35%) and M-wave (IL = -10% vs IK = -17%) significantly decreased immediately postexercise similarly between groups. The changes in muscle damage and neuromuscular function after the exercise are similar between IL and IK, suggesting that resistance modality has little effects on acute muscle responses.

  2. Effect of eccentricity on pattern-pulse multifocal VEP.

    Science.gov (United States)

    Klistorner, Alexander I; Graham, Stuart L

    2005-01-01

    The sparse pattern-pulse stimulation has been suggested to produce better cortical evoked responses compared to pattern reversal stimulation. This study examines varying pattern-pulse states and the effect of eccentricity of the stimulated visual field on the response amplitude and latency. The multifocal visual evoked potential (mfVEP) was recorded using Accumap. 58 close-packed checkerboard segments in a dartboard configuration were used. The best configuration for pattern-pulse stimulation was determined. This optimal stimulus condition was then compared to pattern-reversal stimulation at different eccentricities of visual field.in terms of latency and signal/noise ratio (SNR) of mfVEP amplitude. The maximal response was seen when each element "1" of the binary sequence was represented by two "pattern on" frames followed by two "pattern off" frames while each element "0" of the binary sequence is represented by four "pattern off" frames. There was a significant overall increase of SNR using this pattern-pulse stimulating mode (SNR=15.5+/-3.8) compared with pattern-reversal stimulation (SNR=12.4+/-2.6). However, this was strongly dependant on eccentricity. In rings 1, 2 and 3 SNR improved by 48%, 43% and 26% respectively with ring 4 the effect was marginal and ring 5 was not significantly different. There was also a significant delay (10.1+/-5.3 msec) of the mfVEP response in pattern-pulse stimulation compared to pattern-reversal. The pattern-pulse method offers some advantages for achieving larger mfVEP signals from the central visual field. However, the more peripheral field where it is the most difficult to obtain signals, does not show any benefit.

  3. 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.

  4. Deflection of elastic beam with SMA wires eccentrically inserted

    Science.gov (United States)

    Jamian, S.; Nik Mohamed, N. A.; Ihsan, A. K. A. Mohd; Ismail, A. E.; Nor, M. K. Mohd; Kamarudin, K. A.; Nor, N. H. Muhd

    2017-08-01

    This research is intended to investigate the ability of shape memory alloys (SMA), through its activation, in generating loads to control beam deflection. An elastic beam is formed by sandwiching eccentrically SMA wires between two elastic plates. SMA wires are activated by electrical current from the power supply. Laser displacement meter (LDM) is used to measures deflection of sample. Results show that the deflection of the beam is dependent on the temperature change. The temperature-deflection response also shows the existence of hysteresis.

  5. Residual force enhancement following eccentric induced muscle damage.

    Science.gov (United States)

    Power, Geoffrey A; Rice, Charles L; Vandervoort, Anthony A

    2012-06-26

    During lengthening of an activated skeletal muscle, the force maintained following the stretch is greater than the isometric force at the same muscle length. This is termed residual force enhancement (RFE), but it is unknown how muscle damage following repeated eccentric contractions affects RFE. Using the dorsiflexors, we hypothesised muscle damage will impair the force generating sarcomeric structures leading to a reduction in RFE. Following reference maximal voluntary isometric contractions (MVC) in 8 young men (26.5±2.8y) a stretch was performed at 30°/s over a 30° ankle excursion ending at the same muscle length as the reference MVCs (30° plantar flexion). Surface electromyography (EMG) of the tibialis anterior and soleus muscles was recorded during all tasks. The damage protocol involved 4 sets of 25 isokinetic (30°/s) lengthening contractions. The same measures were collected at baseline and immediately post lengthening contractions, and for up to 10min recovery. Following the lengthening contraction task, there was a 30.3±6.4% decrease in eccentric torque (Pmuscle damage (Pmuscle function compared to isometric actions succeeding damage. Thus, active force of cross-bridges is decreased because of impaired excitation-contraction coupling but force generated during stretch remains intact because force contribution from stretched sarcomeric structures is less impaired.

  6. Transit Timing Variations for Eccentric and Inclined Exoplanets

    Science.gov (United States)

    Nesvorný, David

    2009-08-01

    The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Nontransiting planets in the system can be inferred from TTVs by their gravitational interactions with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Inferring the orbital elements and mass of the nontransiting planets from TTVs, however, is more challenging than for other planet detection schemes. It is a difficult inverse problem. Here, we extended the new inversion method proposed by Nesvorný & Morbidelli to eccentric transiting planets and inclined orbits. We found that the TTV signal can be significantly amplified for hierarchical planetary systems with substantial orbital inclinations and/or for an eccentric transiting planet with anti-aligned orbit of the planetary companion. Thus, a fortuitous orbital setup of an exoplanetary system may significantly enhance our chances of TTV detection. We also showed that the detailed shape of the TTV signal is sensitive to the orbital inclination of the nontransiting planetary companion. The TTV detection method may thus provide important constraints on the orbital inclination of exoplanets and be used to test theories of planetary formation and evolution.

  7. EFFECT OF LINK DIMENSIONS ON D TYPE ECCENTRIC STEEL FRAMES

    Directory of Open Access Journals (Sweden)

    Mazen Ali Musmar

    2013-01-01

    Full Text Available In seismic prone regions, buildings are designed to maintain sufficient stiffness during moderate earthquakes and to absorb and dissipate a large amount of the energy released due to severe earthquakes. The usual steel framing systems; the moment frames require larger member sections to satisfy stiffness requirements and have large ductility capacity, the concentrically braced frames satisfy stiffness on the expense of ductility requirements, resulting in poor energy dissipation. This study deals with the eccentrically Braced Steel Frames (EBF. EBF configuration is similar to traditional braced frames with the exception that at least one end of each brace must be eccentrically connected to the frame. The energy dissipation is achieved through the yielding of a beam segment called the link, while the other frame members, including outer beam segments, braces and columns, should remain essentially elastic. EBFs offer an economical steel framing system satisfying both stiffness and ductility requirements. The study incorporates conducting nonlinear finite element analysis to study the effect of the link length and link section on the behavior of D types EBF systems. The study involves material and geometric nonlinearities.

  8. Equatorial insolation: from precession harmonics to eccentricity frequencies

    Directory of Open Access Journals (Sweden)

    A. Berger

    2006-01-01

    Full Text Available Since the paper by Hays et al. (1976, spectral analyses of climate proxy records provide substantial evidence that a fraction of the climatic variance is driven by insolation changes in the frequency ranges of obliquity and precession variations. However, it is the variance components centered near 100 kyr which dominate most Upper Pleistocene climatic records, although the amount of insolation perturbation at the eccentricity driven periods close to 100-kyr (mainly the 95 kyr- and 123 kyr-periods is much too small to cause directly a climate change of ice-age amplitude. Many attempts to find an explanation to this 100-kyr cycle in climatic records have been made over the last decades. Here we show that the double maximum which characterizes the daily irradiation received in tropical latitudes over the course of the year is at the origin in equatorial insolation of not only strong 95 kyr and 123 kyr periods related to eccentricity, but also of a 11-kyr and a 5.5-kyr periods related to precession.

  9. Eccentric gravitational wave bursts in the post-Newtonian formalism

    Science.gov (United States)

    Loutrel, Nicholas; Yunes, Nicolás

    2017-07-01

    The detection of GW150914 by ground based gravitational wave observatories has brought about a new era in astrophysics. At optimal sensitivity, these observatories are expected to detect several events each year, with one or two of these occurring with non-negligible eccentricity. Such eccentric binaries will emit bursts of gravitational radiation during every pericenter passage, where orbital velocities can reach greater than ten percent the speed of light. As a result, such binaries may prove to be powerful probes of extreme gravitational physics and astrophysics. A promising method of achieving detection of such binaries is through power stacking, where the power in each burst is added up in time-frequency space. This detection strategy requires a theoretical prior of where the bursts will occur in time and frequency so that one knows where to search for successive bursts. We here present a generic post-Newtonian formalism for constructing such time-frequency model priors at generic post-Newtonian order. We apply our formalism to generate a burst model at third post-Newtonian order, making it potentially the most accurate, fully analytic model to date.

  10. Detecting gravitational waves from highly eccentric compact binaries

    CERN Document Server

    Tai, Kai Sheng; Pretorius, Frans

    2014-01-01

    In dense stellar regions, highly eccentric binaries of black holes and neutron stars can form through various n-body interactions. Such a binary could emit a significant fraction of its binding energy in a sequence of largely isolated gravitational wave bursts prior to merger. Given expected black hole and neutron star masses, many such systems will emit these repeated bursts at frequencies within the sensitive band of contemporary ground-based gravitational wave detectors. Unfortunately, existing gravitational wave searches are ill-suited to detect these signals. In this work, we adapt a "power stacking" method to the detection of gravitational wave signals from highly eccentric binaries. We implement this method as an extension of the Q-transform, a projection onto a multiresolution basis of windowed complex exponentials that has previously been used to analyze data from the network of LIGO/Virgo detectors. Our method searches for excess power over an ensemble of time-frequency tiles. We characterize the pe...

  11. A complete waveform model for compact binaries on eccentric orbits

    CERN Document Server

    Huerta, E A; Agarwal, Bhanu; George, Daniel; Schive, Hsi-Yu; Pfeiffer, Harald P; Chu, Tony; Boyle, Michael; Hemberger, Daniel A; Kidder, Lawrence E; Scheel, Mark A; Szilagyi, Bela

    2016-01-01

    We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are non-spinning, and which evolve on orbits with low to moderate eccentricity. The inspiral evolution is described using third order post-Newtonian equations both for the equations of motion of the binary, and its far-zone radiation field. This latter component also includes instantaneous, tails and tails-of-tails contributions, and a contribution due to non-linear memory. This framework reduces to the post-Newtonian approximant $\\texttt{TaylorT4}$ at third post-Newtonian order in the zero eccentricity limit. To improve phase accuracy, we also incorporate higher-order post-Newtonian corrections for the energy flux of quasi-circular binaries and gravitational self-force corrections to the binding energy of compact binaries. This enhanced prescription for the inspiral evolution is combined with a fully analytical prescription for the merger-ringdown evolution constructed using a c...

  12. A Massive Millisecond Pulsar in an Eccentric Binary

    CERN Document Server

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

    2016-01-01

    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 circularised 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 measurement of the both the advance of periastron and Shapiro delay for this system, we determine the mass of the pulsar, companion and the inclination of the orbit to be 1.828(22) Msun, 0.2656(19) Msun and 76.4(6) , under the assumption that general relativity is the true description of gravity. Notably, this is the thi...

  13. Eccentric Inspirals with Self-Force and Spin-Force

    Science.gov (United States)

    Evans, Charles; Osburn, Thomas; Warburton, Niels

    2017-01-01

    Eccentric inspirals of a small mass about a more massive Schwarzschild black hole (EMRIs or IMRIs) are calculated using the gravitational self-force and the Mathisson-Papapetrou spin-force. These calculations include all dissipative and conservative effects that are first order in the mass ratio. We compute systems with initial eccentricities as high as e = 0.8, initial separations as large as 50 M, and arbitrary spin orientations. Including the spin-force causes the orbital plane to precess. Inspirals are calculated using an osculating-orbits scheme that is driven by self-force data from a hybrid self-force code and time-domain spin-force calculations. The hybrid approach uses both self-force data from a Lorenz gauge code and highly accurate flux data from a Regge-Wheeler-Zerilli code, allowing the hybrid model to track orbital phase of inspirals to within 0.1 radians or better over hundreds or thousands of orbits. NSF PHY15-06182.

  14. A Quasi-Stationary Solution to Gliese 436b's Eccentricity

    CERN Document Server

    Batygin, Konstantin; Meschiari, Stefano; Rivera, Eugenio; Vogt, Steve; Butler, Paul

    2009-01-01

    We investigate the possibility that the large orbital eccentricity of the transiting Neptune-mass planet Gliese 436b is maintained in the face of tidal dissipation by a second planet in the system. We find that the currently observed configuration can be understood if Gliese 436b and a putative companion have evolved to a quasi-stationary fixed point in which the planets' orbital apses are co-linear and in which secular variations in the orbital eccentricities of the two planets have been almost entirely damped out. We adopt an octopole-order secular theory based on a Legendre expansion in the semi-major axis ratio to delineate well-defined regions of (P_c, M_c, e_c) space that can be occupied by a perturbing companion. We incorporate the evolutionary effect of tidal dissipation into our secular model of the system, and solve the resulting initial value problems for a large sample of the allowed configurations. We then polish the stationary configurations derived from secular theory with full numerical integr...

  15. 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.

  16. Effects of Movement Velocity and Maximal Concentric and Eccentric Actions on the Bilateral Deficit

    Science.gov (United States)

    Dickin, D. Clark; Too, Danny

    2006-01-01

    This study was performed to examine the effects of movement velocity and maximal concentric and eccentric actions on the bilateral deficit. Eighteen female participants performed maximal unilateral and bilateral knee extensions concentrically and eccentrically across six movement velocities (30, 60, 90, 120, 150, and 180[degrees]/s). Repeated…

  17. Knee Extensor and Flexor Torque Development with Concentric and Eccentric Isokinetic Training

    Science.gov (United States)

    Miller, Larry E.; Pierson, Lee M.; Nickols-Richardson, Sharon M.; Wootten, David F.; Selmon, Serah E.; Ramp, Warren K.; Herbert, William G.

    2006-01-01

    This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training…

  18. 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

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

    NARCIS (Netherlands)

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

    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

  20. Variability in Muscle Damage after Eccentric Exercise and the Repeated Bout Effect

    Science.gov (United States)

    Chen, Trevor C.

    2006-01-01

    The first purpose of this study was to determine a possible explanation for the variability in the response to eccentric exercise by having participants repeat the same exercise 1 year apart. The second purpose was to examine whether initial injury in response to eccentric exercise was associated with the extent of the repeated bout effect (RBE).…

  1. Knee Extensor and Flexor Torque Development with Concentric and Eccentric Isokinetic Training

    Science.gov (United States)

    Miller, Larry E.; Pierson, Lee M.; Nickols-Richardson, Sharon M.; Wootten, David F.; Selmon, Serah E.; Ramp, Warren K.; Herbert, William G.

    2006-01-01

    This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training…

  2. Eccentric exercise slows in vivo microvascular reactivity during brief contractions in human skeletal muscle.

    Science.gov (United States)

    Larsen, Ryan G; Hirata, Rogerio P; Madzak, Adnan; Frøkjær, Jens B; Graven-Nielsen, Thomas

    2015-12-01

    Unaccustomed exercise involving eccentric contractions results in muscle soreness and an overall decline in muscle function, however, little is known about the effects of eccentric exercise on microvascular reactivity in human skeletal muscle. Fourteen healthy men and women performed eccentric contractions of the dorsiflexor muscles in one leg, while the contralateral leg served as a control. At baseline, and 24 and 48 h after eccentric exercise, the following were acquired bilaterally in the tibialis anterior muscle: 1) transverse relaxation time (T2)-weighted magnetic resonance images to determine muscle cross-sectional area (mCSA) and T2; 2) blood oxygen level-dependent (BOLD) images during and following brief, maximal voluntary contractions (MVC) to monitor the hyperemic responses with participants positioned supine in a 3T magnet; 3) muscle strength; and 4) pain pressure threshold. Compared with the control leg, eccentric exercise resulted in soreness, decline in strength (∼20%), increased mCSA (∼7%), and prolonged T2 (∼7%) at 24 and 48 h (P eccentric exercise, such that time-to-peak (∼35%, P eccentric exercise may impede rapid adjustments in muscle blood flow at exercise onset and during activities involving brief bursts of muscle activation, which may impair O2 delivery and contribute to reduced muscle function after eccentric exercise. Copyright © 2015 the American Physiological Society.

  3. Motor unit activity after eccentric exercise and muscle damage in humans.

    Science.gov (United States)

    Semmler, J G

    2014-04-01

    It is well known that unaccustomed eccentric exercise leads to muscle damage and soreness, which can produce long-lasting effects on muscle function. How this muscle damage influences muscle activation is poorly understood. The purpose of this brief review is to highlight the effect of eccentric exercise on the activation of muscle by the nervous system, by examining the change in motor unit activity obtained from surface electromyography (EMG) and intramuscular recordings. Previous research shows that eccentric exercise produces unusual changes in the EMG–force relation that influences motor performance during isometric, shortening and lengthening muscle contractions and during fatiguing tasks. When examining the effect of eccentric exercise at the single motor unit level, there are substantial changes in recruitment thresholds, discharge rates, motor unit conduction velocities and synchronization, which can last for up to 1 week after eccentric exercise. Examining the time course of these changes suggests that the increased submaximal EMG after eccentric exercise most likely occurs through a decrease in motor unit conduction velocity and an increase in motor unit activity related to antagonist muscle coactivation and low-frequency fatigue. Furthermore, there is a commonly held view that eccentric exercise produces preferential damage to high-threshold motor units, but the evidence for this in humans is limited. Further research is needed to establish whether there is preferential damage to high-threshold motor units after eccentric exercise in humans, preferably by linking changes in motor unit activity with estimates of motor unit size using selective intramuscular recording techniques.

  4. Specific training improves skeletal muscle mitochondrial calcium homeostasis after eccentric exercise.

    Science.gov (United States)

    Rattray, Ben; Thompson, Martin; Ruell, Patricia; Caillaud, Corinne

    2013-02-01

    There is limited understanding of the mitochondrial adaptation following repeated eccentric exercise bouts, a model resulting in muscle adaptation known as the repeat bout effect. It was hypothesized that downhill training would reduce mitochondrial calcium content (MCC) post an acute eccentric bout with concurrent improvements in mitochondrial respiratory function. Thirty-four Sprague-Dawley rats were divided into four groups: control (N), control with acute eccentric exercise (N (ecc)), trained control (X) and trained with acute eccentric exercise (X (ecc)). Training for X and X (ecc) consisted of 30 min per day for five consecutive days of downhill treadmill running. The acute eccentric exercise bout was a -14° treadmill exercise for 90 min performed 2 weeks after the training period. Animals were killed 48 h post-exercise. Isolated mitochondria from the red quadriceps allowed for the measure of mitochondrial respiratory indices and MCC. Calpain activity and heat shock protein 72 expression (HSP72) were also measured. MCC dramatically increased following the acute bout of eccentric exercise in N (ecc) (p eccentric exercise. The results suggest that downhill exercise training improves mitochondrial calcium homeostasis following an acute bout of prolonged eccentric exercise and may stabilize mitochondrial respiratory function. These improvements coincide with a reduction in calpain activity and heat shock protein upregulation.

  5. Is eccentric exercise an effective treatment for lateral epicondylitis? A systematic review.

    Science.gov (United States)

    Cullinane, Frances L; Boocock, Mark G; Trevelyan, Fiona C

    2014-01-01

    To establish the effectiveness of eccentric exercise as a treatment intervention for lateral epicondylitis. ProQuest, Medline via EBSCO, AMED, Scopus, Web of Science, CINAHL. A systematic review was undertaken to identify randomized and controlled clinical trials incorporating eccentric exercise as a treatment for patients diagnosed with lateral epicondylitis. Studies were included if: they incorporated eccentric exercise, either in isolation or as part of a multimodal treatment protocol; they assessed at least one functional or disability outcome measure; and the patients had undergone diagnostic testing. The methodological quality of each study was assessed using the Modified Cochrane Musculoskeletal Injuries Group score sheet. Twelve studies met the inclusion criteria. Three were deemed 'high' quality, seven were 'medium' quality, and two were 'low' quality. Eight of the studies were randomized trials investigating a total of 334 subjects. Following treatment, all groups inclusive of eccentric exercise reported decreased pain and improved function and grip strength from baseline. Seven studies reported improvements in pain, function, and/or grip strength for therapy treatments inclusive of eccentric exercise when compared with those excluding eccentric exercise. Only one low-quality study investigated the isolated effects of eccentric exercise for treating lateral epicondylitis and found no significant improvements in pain when compared with other treatments. The majority of consistent findings support the inclusion of eccentric exercise as part of a multimodal therapy programme for improved outcomes in patients with lateral epicondylitis.

  6. Variability in Muscle Damage after Eccentric Exercise and the Repeated Bout Effect

    Science.gov (United States)

    Chen, Trevor C.

    2006-01-01

    The first purpose of this study was to determine a possible explanation for the variability in the response to eccentric exercise by having participants repeat the same exercise 1 year apart. The second purpose was to examine whether initial injury in response to eccentric exercise was associated with the extent of the repeated bout effect (RBE).…

  7. 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...

  8. Study on Flow Characteristic of Non-Newtonian fluid in Eccentric Annulus

    Directory of Open Access Journals (Sweden)

    Li Mingzhong

    2013-08-01

    Full Text Available This study studied the flow characteristic of non-newtonian in eccentric annulus of highly-deviated well. On the basis of dimensionless analysis of motion equations and continuity equation, Hele-Shaw model suitable for fluid flow in the annulus was derived. Combined with H-B rheological model, velocity and stream distribution model were founded and calculated by numerical method. Furthermore, two-dimensional flow characteristic in eccentric annulus was got and the influence of different factors (such as yield stress, pressure gradient or eccentricity on velocity distribution in condition of laminar flow was analyzed. Width of flow core in the annular is proportional to yield stress and inversely proportional to pressure gradient. In eccentric annulus, eccentricity influences the stream distribution remarkably: with the increment of eccentricity, the contour lines of stream function gradually centralize in the widest annular gap, however distribute the most loosely in the narrowest annular gap. Axial velocity is the largest in the widest gap. The larger eccentricity is, the larger contrast of axial velocity between in the widest gap and in the narrowest gap is. There is the largest azimuthal velocity in an annular gap of a certain azimuthal angle, however which equals to zero in the widest and narrowest annular gap separately. The larger eccentricity is, the more homogeneous azimuthal velocity is. The velocity contrast in the entire annulus can be smoothed by increasing pressure gradient, power law index or decreasing yield stress.

  9. 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 cross-sect

  10. Muscle damage and inflammation after eccentric exercise: can the repeated bout effect be removed?

    Science.gov (United States)

    Margaritelis, Nikos V; Theodorou, Anastasios A; Baltzopoulos, Vasilios; Maganaris, Constantinos N; Paschalis, Vassilis; Kyparos, Antonios; Nikolaidis, Michalis G

    2015-12-01

    The current consensus in exercise physiology is that the repeated bout effect always appears after few eccentric exercise sessions. This is the first attempt to challenge this tenet, by exploiting specificity in muscle plasticity. More specifically, we examined whether the opposing adaptations in muscle induced after concentric and eccentric exercise can attenuate and/or remove the repeated bout effect. Seventeen young men were randomly assigned into one of the following groups: (1) the alternating eccentric-concentric exercise group; and (2) the eccentric-only exercise group. Both groups performed 8 weeks of resistance exercise using the knee extensors of both legs on an isokinetic dynamometer. The alternating eccentric-concentric exercise group performed an alternating exercise protocol, switching between eccentric-only and concentric-only exercise every 4 weeks, while the eccentric-only group performed eccentric exercise. Evaluation of muscle damage using physiological (isometric torque, delayed onset muscle soreness, and range of movement) and biochemical (creatine kinase) markers and inflammation (C-reactive protein) was performed at weeks 1, 5, and 10. Baseline isometric peak torque was also evaluated at week 14 after another cycle (4 weeks) of alternating or eccentric-only exercise training. In the alternating eccentric-concentric exercise group, the concentric exercise training performed prior to eccentric exercise reduced dramatically the repeated bout effect by reversing muscle back to its unaccustomed state. On the contrary, the eccentric-only exercise group exhibited a typical manifestation of the repeated bout effect. Interestingly, muscle strength was elevated similarly for both alternating and eccentric-only exercise groups after 13 weeks of training. The alternating eccentric-concentric exercise scheme, implemented in the present study, has for the first time successfully overcame the repeated bout effect. The similarity in muscle strength

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

    Science.gov (United States)

    Moore, Blake; Favata, Marc; Arun, K. G.; Mishra, Chandra Kant

    2016-06-01

    Although gravitational radiation causes inspiralling compact binaries to circularize, a variety of astrophysical scenarios suggest that binaries might have small but non-negligible 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 [M. Favata, Phys. Rev. Lett. 112, 101101 (2014)]. Gravitational-wave search templates typically rely on the quasicircular approximation, which provides relatively simple expressions for the gravitational-wave phase to 3.5 post-Newtonian (PN) order. Damour, Gopakumar, Iyer, and others have developed an elegant but complex quasi-Keplerian formalism for describing 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 nonperiodic contribution to the gravitational-wave phasing can be expressed explicitly as simple functions of frequency or time, with little additional complexity beyond the well-known formulas for circular binaries. These eccentric phase corrections are computed to 3PN order and to leading order in the eccentricity for the standard PN approximants. For a variety of systems, these eccentricity corrections cause significant corrections to the number of gravitational-wave cycles that sweep through a detector's frequency band. This is evaluated using several measures, including a modification of the useful cycles. By comparing to numerical solutions valid for any eccentricity, we find that our analytic solutions are valid up to e0≲0.1 for comparable-mass systems, where e0 is the eccentricity when the source enters the detector band. We also evaluate the role of periodic terms that enter the phasing and discuss how they can be incorporated into some of

  12. Initial partonic eccentricity fluctuations in a multi-phase transport model

    CERN Document Server

    Ma, L; Ma, Y G

    2016-01-01

    Initial partonic eccentricities in Au+Au collisions at center-of-mass energy $\\sqrt{s_{NN}}$ = 200 GeV are investigated using a multi-phase transport model with string melting scenario. The initial eccentricities in different order of harmonics are studied using participant and cumulant definitions. Eccentricity in terms of second-, fourth- and sixth order cumulants as a function of number of participant nucleons are compared systematically with the traditional participant definition. The ratio of the cumulant eccentricities $\\varepsilon\\left\\{4\\right\\}/\\varepsilon\\left\\{2\\right\\}$ and $\\varepsilon\\left\\{6\\right\\}/\\varepsilon\\left\\{4\\right\\}$ are studied in comparison with the ratio of the corresponding flow harmonics. The conversion coefficients ($v_n/\\varepsilon_n$) are explored up to fourth order harmonic based on cumulant method. Furthermore, studies on transverse momentum ($p_T$) and pseudo-rapidity ($\\eta$) dependencies of eccentricities and their fluctuations are presented. As in ideal hydrodynamics in...

  13. The origin of the eccentricity of the hot Jupiter in CI Tau

    CERN Document Server

    Rosotti, Giovanni P; Clarke, Cathie J; Teyssandier, Jean; Facchini, Stefano; Mustill, Alexander J

    2016-01-01

    Following the recent discovery of the first radial velocity planet in a star still possessing a protoplanetary disc (CI Tau), we examine the origin of the planet's eccentricity (e $\\sim 0.3$). We show through long timescale ($10^5$ orbits) simulations that the planetary eccentricity can be pumped by the disc, even when its local surface density is well below the threshold previously derived from short timescale integrations. We show that the disc may be able to excite the planet's orbital eccentricity in $<$ a Myr for the system parameters of CI Tau. We also perform two planet scattering experiments and show that alternatively the observed planet may plausibly have acquired its eccentricity through dynamical scattering of a migrating lower mass planet, which has either been ejected from the system or swallowed by the central star. In the latter case the present location and eccentricity of the observed planet can be recovered if it was previously stalled within the disc's magnetospheric cavity.

  14. Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy

    Science.gov (United States)

    Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

    1992-01-01

    This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

  15. Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy

    Science.gov (United States)

    Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

    1992-01-01

    This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

  16. 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...

  17. The detectability of eccentric compact binary coalescences with advanced gravitational-wave detectors

    CERN Document Server

    Coughlin, Michael; Thrane, Eric; Luo, Jialun; Christensen, Nelson

    2014-01-01

    Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. While most binaries are expected to possess circular orbits, some may be eccentric, for example, if they are formed through dynamical capture. Eccentric orbits can create difficulty for matched filtering searches due to the challenges of creating effective template banks to detect these signals. In previous work, we showed how seedless clustering can be used to detect low-mass ($M_\\text{total}\\leq10M_\\odot$) compact binary coalescences for both spinning and eccentric systems, assuming a circular post-Newtonian expansion. Here, we describe a parameterization that is designed to maximize sensitivity to low-eccentricity ($0\\leq\\epsilon\\leq0.6$) systems, derived from the analytic equations. We show that this parameterization provides a robust and computationally efficient method for detecting eccentric low-mass compact binaries. Base...

  18. Orbital Parameters of the Eclipsing Detached Kepler Binaries with Eccentric Orbits

    Science.gov (United States)

    Kjurkchieva, Diana; Vasileva, Doroteya; Atanasova, Teodora

    2017-09-01

    We present precise values of the eccentricity and periastron angle of 529 detached, eccentric, eclipsing stars from the Kepler Eclipsing Binary catalog that were determined by modeling their long cadence data. The temperatures and relative radii of their components as well as their mass ratios were calculated based on approximate values of the empirical relations of MS stars. Around one-third of the secondary components were revealed to be very late dwarfs, some of them possible brown dwarf candidates. Most of our targets fall below the envelope P(1 - e 2)3/2 = 5 days. The (e, P) distribution of the known eccentric binaries exhibits a rough trend of increasing eccentricity with the period. The prolonged and continuous Kepler observations allowed us to identify 60 new highly eccentric targets with e > 0.5.

  19. On the Eccentricity Distribution of Short-Period Single-Planet Systems

    CERN Document Server

    Wang, Ji

    2011-01-01

    We apply standard Markov chain Monte Carlo (MCMC) analysis techniques for 50 short- period, single-planet systems discovered with radial velocity technique. We develop a new method for accessing the significance of a non-zero orbital eccentricity, namely {\\Gamma} analysis, which combines frequentist bootstrap approach with Bayesian analysis of each simulated data set. We find the eccentricity estimations from {\\Gamma} analysis are generally consistent with results from both standard MCMC analysis and previous references. The {\\Gamma} method is particular useful for assessing the significance of small eccentricities. Our results suggest that the current sample size is insufficient to draw robust conclusions about the roles of tidal interaction and perturbations in shaping the eccentricity distribution of short-period single-planet systems. We use a Bayesian population analysis to show that a mixture of analytical distributions is a good approximation of the underlying eccentricity distribution. For short-perio...

  20. The Photoeccentric Effect and Proto-Hot-Jupiters I. Measuring photometric eccentricities of individual transiting planets

    CERN Document Server

    Dawson, Rebekah I

    2012-01-01

    Exoplanet orbital eccentricities offer valuable clues about the origins and orbital evolution of planetary systems. Eccentric, Jupiter-sized planets are particularly interesting: they may link the "cold" Jupiters beyond the ice line to hot Jupiters at a fraction of an AU, where they are unlikely to have formed in situ. To date, all eccentricities of individual planets 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 --- the "photoeccentric effect" --- even with long-cadence Kepler photometry and loosely-constrained stellar parameters. A Markov Chain Monte Carlo exploration of para...

  1. Frequency and time domain inspiral templates for comparable mass compact binaries in eccentric orbits

    CERN Document Server

    Tanay, Sashwat; Gopakumar, Achamveedu

    2016-01-01

    Inspiraling compact binaries with non-negligible orbital eccentricities are plausible gravitational wave (GW) sources for the upcoming network of GW observatories. In this paper, we present two prescriptions to compute post-Newtonian (PN) accurate inspiral templates for such binaries. First, we adapt and extend the post-circular scheme of Yunes {\\it et al.} [Phys. Rev. D 80, 084001 (2009)] to obtain a Fourier-domain inspiral approximant that incorporates the effects of PN-accurate orbital eccentricity evolution. This results in a fully analytic frequency-domain inspiral waveform with Newtonian amplitude and 2PN order Fourier phase while incorporating eccentricity effects up to sixth order at each PN order. The importance of incorporating eccentricity evolution contributions to the Fourier phase in a PN consistent manner is also demonstrated. Second, we present an accurate and efficient prescription to incorporate orbital eccentricity into the quasi-circular time-domain {\\texttt{TaylorT4}} approximant at 2PN o...

  2. A weekly bout of eccentric exercise is sufficient to induce health-promoting effects.

    Science.gov (United States)

    Paschalis, Vassilis; Nikolaidis, Michalis G; Theodorou, Anastasios A; Panayiotou, George; Fatouros, Ioannis G; Koutedakis, Yiannis; Jamurtas, Athanasios Z

    2011-01-01

    The effects of chronic eccentric-only versus concentric-only exercise on muscle physiology and blood biochemistry were investigated. Twenty women performed on an isokinetic dynamometer a concentric (n = 10;mean ± SEM: age = 21.0 ± 0.4 yr, body fat = 22.0% ± 0.9%) or an eccentric (n = 10, age = 20.0 ± 0.3 yr, body fat = 23.2% ± 0.7%) exercise session using the knee extensors of both lower limbs once a week for eight subsequent weeks. Muscle function (isometric, concentric, and eccentric peak torque, range of movement, and soreness) was evaluated before, immediately after, and 48 h postexercise in each one of the eight training weeks. Body fat, resting energy expenditure (REE), lipid, and carbohydrate oxidation rate as well as blood chemistry measurements (lipid, lipoprotein and apolipoprotein profile, glucose, insulin, glycosylated hemoglobin, and creatine kinase) were examined before and 48 h postexercise at the first and eighth week of training. Acute eccentric exercise increased REE and fat oxidation at week 1 (12.7% and 12.9%, respectively) and at week 8 (0.7% and 2.8%, respectively). Chronic eccentric exercise increased resting REE and fat oxidation at week 8 compared with week 1 (5.0% and 9.9%, respectively). Acute eccentric exercise improved blood lipid profile at week 1 and week 8. Chronic eccentric exercise improved resting blood lipid profile at week 8. Acute eccentric exercise increased insulin resistance at week 1 but not at week 8. Chronic eccentric exercise decreased resting insulin resistance at week 8. It is reported for the first time that only 30 min of eccentric exercise per week for 8 wk was sufficient to improve health risk factors.

  3. Acute Effect of High-Intensity Eccentric Exercise on Vascular Endothelial Function in Young Men.

    Science.gov (United States)

    Choi, Youngju; Akazawa, Nobuhiko; Zempo-Miyaki, Asako; Ra, Song-Gyu; Shiraki, Hitoshi; Ajisaka, Ryuichi; Maeda, Seiji

    2016-08-01

    Choi, Y, Akazawa, N, Zempo-Miyaki, A, Ra, S-G, Shiraki, H, Ajisaka, R, and Maeda, S. Acute effect of high-intensity eccentric exercise on vascular endothelial function in young men. J Strength Cond Res 30(8): 2279-2285, 2016-Increased central arterial stiffness is as an independent risk factor for cardiovascular disease. Evidence regarding the effects of high-intensity resistance exercise on vascular endothelial function and central arterial stiffness is conflicting. The purpose of this study was to examine the effects of acute high-intensity eccentric exercise on vascular endothelial function and central arterial stiffness. We evaluated the acute changes in endothelium-dependent flow-mediated dilation (FMD), low-flow-mediated constriction (L-FMC), and arterial stiffness after high-intensity eccentric exercise. Seven healthy, sedentary men (age, 24 ± 1 year) performed maximal eccentric elbow flexor exercise using their nondominant arm. Before and 45 minutes after eccentric exercise, carotid arterial compliance and brachial artery FMD and L-FMC in the nonexercised arm were measured. Carotid arterial compliance was significantly decreased, and β-stiffness index significantly increased after eccentric exercise. Brachial FMD was significantly reduced after eccentric exercise, whereas there was no significant difference in brachial L-FMC before and after eccentric exercise. A positive correlation was detected between change in arterial compliance and change in FMD (r = 0.779; p ≤ 0.05), and a negative correlation was detected between change in β-stiffness index and change in FMD (r = -0.891; p eccentric exercise. In this study, acute high-intensity eccentric exercise increased central arterial stiffness; this increase was accompanied by a decrease in endothelial function caused by reduced endothelium-dependent vasodilation but not by a change in endothelium-dependent vasoconstriction.

  4. Habitability of planets on eccentric orbits: Limits of the mean flux approximation

    Science.gov (United States)

    Bolmont, Emeline; Libert, Anne-Sophie; Leconte, Jeremy; Selsis, Franck

    2016-06-01

    Unlike the Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of ~0.97 for HD 20782 b). This raises the question of whether these planets have surface conditions favorable to liquid water. In order to assess the habitability of an eccentric planet, the mean flux approximation is often used. It states that a planet on an eccentric orbit is called habitable if it receives on average a flux compatible with the presence of surface liquid water. However, because the planets experience important insolation variations over one orbit and even spend some time outside the HZ for high eccentricities, the question of their habitability might not be as straightforward. We performed a set of simulations using the global climate model LMDZ to explore the limits of the mean flux approximation when varying the luminosity of the host star and the eccentricity of the planet. We computed the climate of tidally locked ocean covered planets with orbital eccentricity from 0 to 0.9 receiving a mean flux equal to Earth's. These planets are found around stars of luminosity ranging from 1 L⊙ to 10-4L⊙. We use a definition of habitability based on the presence of surface liquid water, and find that most of the planets considered can sustain surface liquid water on the dayside with an ice cap on the nightside. However, for high eccentricity and high luminosity, planets cannot sustain surface liquid water during the whole orbital period. They completely freeze at apoastron and when approaching periastron an ocean appears around the substellar point. We conclude that the higher the eccentricity and the higher the luminosity of the star, the less reliable the mean flux approximation.

  5. High post-Newtonian order gravitational self-force analytical results for eccentric orbits around a Kerr black hole

    CERN Document Server

    Bini, Donato; Geralico, Andrea

    2016-01-01

    We present the first analytic computation of the Detweiler-Barack-Sago gauge-invariant redshift function for a small mass in {\\it eccentric} orbit around a {\\it spinning} black hole. Our results give the redshift contributions that mix eccentricity and spin effects, through second order in eccentricity, second order in spin parameter, and the eight-and-a-half post-Newtonian order.

  6. Two Timescale Approximation Applied to Gravitational Waves from Eccentric EMRIs

    Science.gov (United States)

    Moxon, Jordan; Flanagan, Eanna; Hinderer, Tanja; Pound, Adam

    2016-03-01

    Gravitational-wave driven inspirals of compact objects into massive black holes (Extreme Mass Ratio Inspirals - EMRIs) form an interesting, long-lived signal for future space-based gravitational wave detectors. Accurate signal predictions will be necessary to take full advantage of matched filtering techniques, motivating the development of a calculational technique for deriving the gravitational wave signal to good approximation throughout the inspiral. We report on recent work on developing the two-timescale technique with the goal of predicting waveforms from eccentric equatorial systems to subleading (post-adiabatic) order in the phase, building on recent work by Pound in the scalar case. The computation requires us to understand the dissipative component of the second-order self force. It also demands careful consideration of how the two timescale (near-zone) approximation should match with the post-Minkowski approximation of the gravitational waves at great distances.

  7. 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.

  8. What velocities and eccentricities tell us about radial migration

    Directory of Open Access Journals (Sweden)

    Schönrich R.

    2012-02-01

    Full Text Available This note attempts to interpret some of the recent findings about a downtrend in the mean azimuthal velocity of low [α/Fe] thin disc stars with increasing metallicity. The presence of such a trend was predicted in the model of [19], albeit with a slightly steeper slope. We show that in a simple picture a Galactic disc without mixing in angular momenta would display an exceedingly steep trend, while in the case of complete mixing of all stars the trend has to vanish. The difference between model and observational data can hence be interpreted as the consequence of the radial abundance gradient in the model being too high resulting in an underestimate of the migration strength. We shortly discuss the value of eccentricity distributions in constraining structure and history of the Galactic disc.

  9. Investigation of Stress Indices and Directional Loading of Eccentric Reducers

    Energy Technology Data Exchange (ETDEWEB)

    R. Carter,E.A. Wais, E.C. Rodabaugh

    2003-08-01

    OAK- B135 Engineering for fatigue is an essential concern in piping systems. Addressing this concern, the ASME Section III and ANSI B31.1 Codes provide stress indices and stress intensification factors (SIFs) to be used in the design and evaluation of Class 1, 2 and 3 systems. In recent research cosponsored by EPRI and the U.S. DOE, new test data have been developed for comparison with the ASME stress indices and SIFs. This report presents the results of fatigue tests on eccentric reducers, taking into account the directionality of the loading. As detailed in the report, the results can help to improve the evaluation of reducers and can help to reduce unnecessary conservatism in piping system design.

  10. A numerical study of natural convection in eccentric spherical annuli

    Science.gov (United States)

    Gallegos, Angel; Malaga, Carlos

    2016-11-01

    A fluid between two spheres, concentric or not, at different temperatures will flow in the presence of a constant gravitational force. Although there is no possible hydrostatic state, energy transport is dominated by diffusion if temperature difference between the spheres is small enough. By the use of a full three-dimensional thermal lattice Boltzmann model we study the transition between the conductive, the steady convective, and the unsteady convective regimes. We use the concentric case to validate the results by comparing with experiments and numerical simulations found in the literature, and then we extend our numerical experiments to the eccentric case to observe the general behavior of the different regimes. We analyze the energy transport characterized by the relation between Nusselt and Rayleigh numbers as well as the arising flow patterns. This work was partially supported by UNAM-DGAPA-PAPIIT Grant Number IN115216.

  11. Bilateral eccentric vision training on pseudovitelliform dystrophy with microperimetry biofeedback

    Science.gov (United States)

    Morales, Marco Ulises; Saker, Saker; Amoaku, Winfried M

    2015-01-01

    Low vision patients with eccentric viewing (EV) use extrafoveal retinal areas to compensate for the loss of central vision. Such retinal loci are known as the preferred retinal locus (PRL). It is known that EV is accompanied by unstable fixation. Microperimetry systems with biofeedback training have been used as a rehabilitation aid to improve fixation stability in EV patients. Normally, only the best or dominant eye is selected for such rehabilitation. This case report describes the rehabilitation on both eyes by means of PRL relocation with MAIA microperimetry (Centervue, Padova, Italy) with biofeedback training technology of a 74-year-old woman diagnosed with adult pseudovitelliform dystrophy. The patient presented binocularly similar anatomical and functional characteristics with the PRL located over the dystrophic area. At the end of the 3 months rehabilitation period, the PRL was successfully relocated inferiorly from the fovea showing relevant visual acuity improvement. PMID:25576513

  12. Unsteady Flow Produced by Oscillations of Eccentric Rotating Disks

    Directory of Open Access Journals (Sweden)

    H. Volkan Ersoy

    2012-01-01

    Full Text Available While the disks are initially rotating eccentrically, the unsteady flow caused by their oscillations in their own planes and in the opposite directions is studied. The analytical solutions to the problem are obtained for both small and large times, and thus the velocity field is determined for every value of time. The variations of all the parameters on the flow are scrutinized by means of the graphical representations. In particular, the effect of the ratio of the frequency of oscillation to the angular velocity of the disks is analyzed. The dependence of the oscillations in both - and -directions on the flow is examined. The influence of the Reynolds number is also investigated.

  13. Highly eccentric exoplanets trapped in mean-motion resonances

    CERN Document Server

    Antoniadou, K I

    2015-01-01

    We herein utilize the general three-body problem (GTBP) as a model, in order to simulate resonant systems consisting of a star and two planets, where at least one of them is highly eccentric. We study them in terms of their long-term stability, via the construction of maps of dynamical stability and the computation of the corresponding families of periodic orbits. We identify the way their survival is connected with the regions of regular motion in phase space, which, in turn, were created by stable resonant periodic orbits in their vicinity. Consequently, a phase protection mechanism is provided and the planets avoid close encounters and collisions even on long timescales. We apply our methodology to the extrasolar system HD 82943.

  14. 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.

  15. 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.

  16. Habitability of planets on eccentric orbits: the limits of the mean flux approximation

    CERN Document Server

    Bolmont, Emeline; Leconte, Jérémy; Selsis, Franck

    2016-01-01

    Contrary to Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of $\\sim0.97$ for HD~20782~b). This raises the question of the capacity of these planets to host surface liquid water. In order to assess the habitability of an eccentric planet, the mean flux approximation is often used. It states that a planet on an eccentric orbit is called habitable if it receives on average a flux compatible with the presence of surface liquid water. However, as the planets do experience important insolation variations over one orbit and even spend some time outside the HZ for high eccentricities, the question of their habitability might not be as straightforward. We performed a set of simulations using the Global Climate Model LMDz, exploring the limits of the mean flux approximation when varying the luminosity of the host star and the eccentricity of the planet. We computed the climate of tidally locked...

  17. 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 eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction.

  18. Muscle changes with eccentric exercise: Implications on earth and in space

    Science.gov (United States)

    Hargens, Alan R.; Parazynski, Scott; Aratow, Michael; Friden, Jan

    1989-01-01

    Recent investigations of fluid pressure, morpholo gy, and enzyme activities of skeletal muscle exercised eccentrically or concentrically in normal human subjects are reviewed. Intramuscular pressures were measured before, during, and after submaximal exercise and correlated with subjective muscle soreness, fiber size, water content, and blood indices of muscle enzymes. High intensity eccentric exercise is characterized by post exercise pain, elevated intramuscular pressures, and swelling of both type 1 and 2 fibers as compared to concentric exercise. Thus, long periods of unaccustomed, high level eccentric contraction may cause muscle injury, fiber swelling, fluid accumulation, elevated intramuscular pressure, and delayed muscle soreness. Training regimens of progressively increasing eccentric exercise, however, cause less soreness and are extremely efficacious in increasing muscle mass and strength. It is proposed that on Earth, postural muscles are uniquely adapted to low levels of prolonged eccentric contraction that are absent during weightlessness. The almost complete absence of eccentric exercise in space may be an important contributor to muscle atrophy and therefore equipment should be designed to integrate eccentric contractions into exercise protocols for long-term spaceflight.

  19. 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.

  20. Detectability of eccentric compact binary coalescences with advanced gravitational-wave detectors

    Science.gov (United States)

    Coughlin, M.; Meyers, P.; Thrane, E.; Luo, J.; Christensen, N.

    2015-03-01

    Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. While most binaries are expected to possess circular orbits, some may be eccentric, for example, if they are formed through dynamical capture. Eccentric orbits can create difficulty for matched filtering searches due to the challenges of creating effective template banks to detect these signals. In previous work, we showed how seedless clustering can be used to detect low-mass (Mtotal≤10 M⊙) compact binary coalescences for both spinning and eccentric systems, assuming a circular post-Newtonian expansion. Here, we describe a parametrization that is designed to maximize sensitivity to low-eccentricity (0 ≤ɛ ≤0.6 ) systems, derived from the analytic equations. We show that this parametrization provides a robust and computationally efficient method for detecting eccentric low-mass compact binaries. Based on these results, we conclude that advanced detectors will have a chance of detecting eccentric binaries if optimistic models prove true. However, a null observation is unlikely to firmly rule out models of eccentric binary populations.

  1. Muscle-Tendon Unit Properties during Eccentric Exercise Correlate with the Creatine Kinase Response

    Directory of Open Access Journals (Sweden)

    Kirsty M. Hicks

    2017-09-01

    Full Text Available Aim: The aim of this paper was to determine whether; (1 patella tendon stiffness, (2 the magnitude of vastus lateralis fascicle lengthening, and (3 eccentric torque correlate with markers of exercise induced muscle damage.Method: Combining dynamometry and ultrasonography, patella tendon properties and vastus lateralis architectural properties were measured pre and during the first of six sets of 12 maximal voluntary eccentric knee extensions. Maximal isometric torque loss and creatine kinase activity were measured pre-damage (−48 h, 48, 96, and 168 h post-damage as markers of exercise-induced muscle damage.Results: A significant increase in creatine kinase (883 ± 667 UL and a significant reduction in maximal isometric torque loss (21% was reported post-eccentric contractions. Change in creatine kinase from pre to peak significantly correlated with the relative change in vastus lateralis fascicle length during eccentric contractions (r = 0.53, p = 0.02 and with eccentric torque (r = 0.50, p = 0.02. Additionally, creatine kinase tended to correlate with estimated patella tendon lengthening during eccentric contractions (p < 0.10. However, creatine kinase did not correlate with resting measures of patella tendon properties or vastus lateralis properties. Similarly, torque loss did not correlate with any patella tendon or vastus lateralis properties at rest or during eccentric contractions.Conclusion: The current study demonstrates that the extent of fascicle strain during eccentric contractions correlates with the magnitude of the creatine kinase response. Although at rest, there is no relationship between patella tendon properties and markers of muscle damage; during eccentric contractions however, the patella tendon may play a role in the creatine kinase response following EIMD.

  2. 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

  3. 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

    2015-04-01

    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. 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. 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. 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 and estrogen supplemented groups. The findings suggest

  4. 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.

  5. Prediction and analysis of magnetic forces in permanent magnet brushless dc motor with rotor eccentricity

    Science.gov (United States)

    Liu, Z. J.; Li, J. T.; Jabbar, M. A.

    2006-04-01

    In design of permanent magnet motors for high-precision applications, it is sometimes necessary, early in the design stage, to have a detailed analysis of the effect of rotor eccentricity that may result from manufacturing imperfectness or use of fluid dynamic or aerodynamic bearings. This paper presents an analytical model for electromagnetic torque and forces in permanent magnet motors with rotor eccentricity. The model gives an insight to the relationship between the effect of the eccentricity and the other motor design parameters on the electromagnetic forces. It is shown that the calculated magnetic forces obtained from this model agree well with those obtained from numerical simulations that are very computationally demanding.

  6. Eccentric exercise inhibits the H reflex in the middle part of the trapezius muscle

    DEFF Research Database (Denmark)

    Vangsgaard, Steffen; Nørgaard, Lars Tønners; Korsholm Flaskager, Brian

    2013-01-01

    The objectives of this study were to (1) investigate the modulation of the H reflex immediately after and 24 h after eccentric exercise in the presence of delayed-onset muscle soreness (DOMS) and (2) test the reproducibility of the H reflex in trapezius across days. H reflexes were recorded from...... the dominant middle trapezius muscle by electrical stimulation of the C3/4 cervical nerve in ten healthy subjects. DOMS was induced by eccentric exercise of the dominant shoulder. H reflexes were obtained in four sessions: "24 h before", "Pre", "Post", and "24 h after" eccentric exercise. Ratios of maximal H...

  7. First order post-Newtonian gravitational waveforms of binaries on eccentric orbits with Hansen coefficients

    Science.gov (United States)

    Mikóczi, Balázs; Forgács, Péter; Vasúth, Mátyás

    2015-08-01

    The inspiral and merger of supermassive black hole binary systems with high orbital eccentricity are among the promising sources of the advanced gravitational wave observatories. In this paper we compute gravitational waveforms in the frequency domain to the first post-Newtonian order, emitted by compact binary systems with arbitrary eccentricity. Our results are fully analytic, ready-to-use expressions of the waveforms in terms of a suitable generalization of Hansen coefficients known from celestial mechanics. Secular terms induced by the eccentricity are eliminated by introducing a suitable phase shift. The obtained waveforms have a rather simple structure, greatly facilitating their use in applications.

  8. Buckling analysis of stringer-stiffened laminated cylindrical shells with nonuniform eccentricity

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghifar, M. [Islamic Azad University, Department of Mechanical Engineering, Nowshahr Branch, Nowshahr (Iran, Islamic Republic of); Bagheri, M. [Sattari Air University, Faculty of Aerospace Engineering, Tehran (Iran, Islamic Republic of); Jafari, A.A. [K.N. Toosi University of Technology, Faculty of Mechanical Engineering, Tehran (Iran, Islamic Republic of)

    2011-07-15

    In this study, the influence of nonuniformity of eccentricity of stringers on the general axial buckling load of stiffened laminated cylindrical shells with simply supported end conditions is investigated. The critical loads are calculated using Love's First-order Shear Deformation Theory and solved using the Rayleigh-Ritz procedure. The effects of the shell length-to-radius ratio, shell thickness-to-radius ratio, number of stringers, and stringers depth-to-width ratio on the buckling load of nonuniformly eccentric shells, are examined. The research demonstrates that an appropriate nonuniform distribution of eccentricity of stringers leads the buckling load to increase significantly. (orig.)

  9. Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the knee extensors in the elderly.

    Science.gov (United States)

    Chen, Trevor C; Tseng, Wei-Chin; Huang, Guan-Ling; Chen, Hsin-Lian; Tseng, Kou-Wei; Nosaka, Kazunori

    2013-04-01

    This study investigated whether low-intensity eccentric contractions of the knee extensors would attenuate the magnitude of muscle damage induced by maximal eccentric exercise of the same muscle performed 7 days later using elderly individuals. Healthy older men (66.4 ± 4.6 years) were assigned to control or experimental (Exp) group (n = 13 per group). The control group performed six sets of ten maximal eccentric contractions (MaxECC) of the knee extensors of non-dominant leg. The Exp group performed six sets of ten low-intensity eccentric contractions of the knee extensors on a leg extension machine by lowering a weight of 10 % maximal voluntary isometric knee extension strength (10 %ECC) 7 days prior to MaxECC. Changes in maximal voluntary isokinetic concentric torque (MVC-CON), angle at peak torque, range of motion (ROM), upper thigh circumference, muscle soreness, plasma creatine kinase activity and myoglobin (Mb) concentration and B-mode ultrasound echo-intensity before and for 5 days after MaxECC were compared between groups by a mixed factor ANOVA. No significant changes in any variables were observed following 10 %ECC. Following MaxECC, all variables changed significantly, and changes in all variables except for angle at peak torque were significantly different between groups. MVC-CON and ROM decreased smaller and recovered faster (P eccentric contractions was effective for attenuating muscle damage induced by subsequent MaxECC of the knee extensors for elderly individuals.

  10. 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.

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

    National Research Council Canada - National Science Library

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

    2015-01-01

    .... 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...

  12. A Proposed Search for the Detection of Gravitational Waves from Eccentric Binary Black Holes

    CERN Document Server

    Tiwari, Vaibhav; Christensen, Nelson; Huerta, Eliu; Mohapatra, Satya; Gopakumar, Achamveedu; Haney, Maria; Parameswaran, Ajith; McWilliams, Sean; Vedovato, Gabriele; Drago, Marco; Salemi, Francesco; Prodi, Giovanni; Lazzaro, Claudia; Tiwari, Shubhanshu; Mitselmakher, Guenakh; Da Silva, Filipe

    2015-01-01

    Most of compact binary systems are expected to circularize before the frequency of emitted gravitational waves (GWs) enters the sensitivity band of the ground based interferometric detectors. However, several mechanisms have been proposed for the formation of binary systems, which retain eccentricity throughout their lifetimes. Since no matched-filtering algorithm has been developed to extract continuous GW signals from compact binaries on orbits with low to moderate values of eccentricity, and available algorithms to detect binaries on quasi-circular orbits are sub-optimal to recover these events, in this paper we propose a search method for detection of gravitational waves produced from the coalescences of eccentric binary black holes (eBBH). We study the search sensitivity and the false alarm rates on a segment of data from the second joint science run of LIGO and Virgo detectors, and discuss the implications of the eccentric binary search for the advanced GW detectors.

  13. 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...

  14. 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

    It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime...... of heavy-resistance eccentric training apart from their regular training and soccer activity. Before and after the training period the tissue concentration of indicators of collagen turnover was measured by the use of the microdialysis technique. After training, collagen synthesis was increased...... 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...

  15. 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...... 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...... muscles from rats were stimulated for eccentric (EC) or concentric (CC) contractions or were passively stretched (ST). Muscles from unstimulated control (CT) rats were also studied. Two days later, all rats had their isolated hindlimbs perfused either at rest or during 15 min of isometric muscle...

  16. 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

  17. 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.

  18. 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.

  19. Resonant relaxation near a massive black hole: the dependence on eccentricity

    CERN Document Server

    Gürkan, M Atakan

    2007-01-01

    The orbits of stars close to a massive black hole are nearly Keplerian ellipses. Such orbits exert long term torques on each other, which lead to an enhanced angular momentum relaxation known as resonant relaxation. Under certain conditions, this process can modify the angular momentum distribution and affect the interaction rates of the stars with the massive black hole more efficiently than non-resonant relaxation. The torque on an orbit exerted by the cluster depends on the eccentricity of the orbit. In this paper, we calculate this dependence and determine the resonant relaxation timescale as a function of eccentricity. In particular, we show that the component of the torque that changes the magnitude of the angular momentum is linearly proportional to eccentricity, so resonant relaxation is much more efficient on eccentric orbits than on circular orbits.

  20. Eccentrically Loaded Small Scale Ring Footing on Resting on Cohesionless Soil

    Directory of Open Access Journals (Sweden)

    Dr. A. I. Dhatrak

    2016-08-01

    Full Text Available A number of works have been carried out for the evaluation of a ultimate bearing capacity of shallow foundation, supported by geogrid reinforced sand and subjected to centric load. Few experimental studies have been made on the calculation of bearing capacity of shallow foundation on geogrid-reinforced sand under eccentric loading. However these studies are for strip footings. This paper presents the behavior of ring footing under eccentric loading on sand. The model tests have been conducted using ring footing with ring radii ratio (Di/Do = 0.4, 0.6, 0.8 for varring eccentricity ratio. Parametric studies have been made to find the impact of eccentricity ratio, ring radii ratio and geogrid reinforcement on bearing capacity of the foundation.

  1. 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.

  2. Eccentricity on AN Image Caused by Projection of a Circle and a Sphere

    Science.gov (United States)

    Matsuoka, R.; Maruyama, S.

    2016-06-01

    Circular targets on a plane are often utilized in photogrammetry, particularly in close range photogrammetry, while spherical targets are sometimes utilized in industrial applications. Both a circle and a sphere are projected as an ellipse onto an image. There is an eccentricity on an image between the centre of the projected ellipse and the projected location of the centre of a circle or a sphere. Since only the centre of the projected ellipse is measured, the correction of the eccentricity is considered to be necessary for highly accurate measurement. This paper shows a process to derive general formulae to calculate an eccentricity of a circle and a sphere using the size and the location of a circle or a sphere, and the focal length, the position and the attitude of a camera. Furthermore the paper shows methods to estimate the eccentricity of a circle and a sphere from the equation of the projected ellipse of a circle or a sphere on an image.

  3. A numerical study of entrance region in a curved annulus with an inward and outward eccentricity

    Directory of Open Access Journals (Sweden)

    M.R.H. Nobari

    2016-09-01

    Full Text Available In this article, developing incompressible fluid flow in a curved annulus with inward and outward eccentricities is studied numerically. To do so, a second order finite difference method based on the projection algorithm is employed to solve the governing equations written in a general bipolar–toroidal coordinate system using a three-dimensional staggered uniform grid. The effects of the governing dimensionless parameters such as the Dean number, Reynolds number, curvature ratio, aspect ratio, and eccentricity on the flow field pattern and friction factor are studied in the entrance region. The numerical results obtained indicate that the outward eccentricity significantly deforms the secondary flows and axial velocity profiles. Furthermore, as the eccentricity increases, the friction factor decreases due to the reduction of secondary flow intensity.

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

    OpenAIRE

    Michelle eMoyer; Erik evan Lunteren

    2012-01-01

    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...

  5. The Effects of K+ Channel Blockade on Eccentric and Isotonic Twitch and Fatiguing Contractions in situ

    OpenAIRE

    van Lunteren, Erik; Moyer, Michelle

    2012-01-01

    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% l...

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

    OpenAIRE

    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 s...

  7. Functional and morphological changes in the quadriceps muscle induced by eccentric training after ACL reconstruction

    OpenAIRE

    Brasileiro,Jamilson S.; Pinto,Olga M. S. F.; Mariana A. Ávila; Tania F. Salvini

    2011-01-01

    OBJECTIVES: The purpose of this study was to investigate the contributions of functional and morphological factors in the recovery of the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction. METHODS: Nine subjects (31.3±5.8 years) underwent eccentric exercise sessions twice a week for 12 weeks. Quadriceps muscle function was evaluated using an isokinetic dynamometer (isometric and eccentric peak torque) and electromyography (RMS). Morphological changes were measured using ...

  8. EFFECTS OF ECCENTRIC EXERCISE ON ANAEROBIC POWER, STARTING SPEED AND ANAEROBIC ENDURANCE

    OpenAIRE

    Maciejczyk, Marcin; Szymura, Jadwiga; Wiecek, Magdalena; Szygula, Zbigniew; Kepinska, Magdalena; Ochalek, Katarzyna; Pokrywka, Andrzej

    2015-01-01

    The aim of this study was to evaluate the effects of eccentric exercise on anaerobic power, starting speed and anaerobic endurance. The participants performed the maximum cycling sprint test (MCST) prior to eccentric exercise (ECC), 10 minutes after, as well as one hour, 24 hours, 48 hours, and one week after ECC. The peak and mean power, time to attain peak power, time of maintaining peak power and power decrease were measured in the MCST. Before and after ECC, the myoglobin concentration...

  9. Hamstring Architectural and Functional Adaptations Following Long vs. Short Muscle Length Eccentric Training

    Science.gov (United States)

    Guex, Kenny; Degache, Francis; Morisod, Cynthia; Sailly, Matthieu; Millet, Gregoire P.

    2016-01-01

    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) vs. short muscle length (SML). Both groups performed eight sessions of 3–5 × 8 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 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, further investigations are required to confirm the hypothesis that performing eccentric exercises at LML may lead to greater adaptations than a similar training performed at SML. PMID:27536252

  10. Osculating Relative Orbit Elements Resulting from Chief Eccentricity and J2 Perturbing Forces

    Science.gov (United States)

    2011-03-01

    eccentricity as a perturbation to the linearized HCW model using Hamiltonian mechanics . Another non-traditional solution is that of Vadali [25] and Sengupta...numerous partial deriva- tives and extensive use of Lagrangian mechanics will yield Lagrange’s planetary equa- tions, presented in Eq. 2.66 using... Hamiltonian Ap- proach to Eccentricity Perturbations,” AAS/AIAA Spacecraft Mechanics Meet- ing , Vol. 119, 2004, pp. 3075–3086. 25. Vadali, S. R., “An

  11. 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.

  12. Detecting eccentricity faults in a PMSM in non-stationary conditions

    OpenAIRE

    Javier Rosero García; José Luis Romeral; Esteban Rosero García

    2012-01-01

    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 m...

  13. Timing the Eccentric Binary Millisecond Pulsar in NGC 1851

    CERN Document Server

    Freire, P C; Gupta, Y; Freire, Paulo C.; Ransom, Scott M.; Gupta, Yashwant

    2007-01-01

    We have used the Green Bank Telescope to observe the millisecond pulsar PSR J0514-4002A on 43 occasions spread over 2 years. This 5-ms pulsar is located in the globular cluster NGC 1851; it belongs to a binary system and has a highly eccentric (e = 0.888) orbit. We have obtained a phase-coherent timing solution for this object, including very precise position, spin and orbital parameters. The pulsar is located 4.6" (about 1.3 core radii) from the center of the cluster, and is likely to lie on its more distant half. The non-detection of eclipses at superior conjunction can be used, given the peculiar geometry of this system, to rule out the possibility of an extended companion. We have measured the rate of advance of periastron for this binary system to be $\\dot{\\omega}$ = 0.01289(4) degrees per year, which if due completely to general relativity, implies a total system mass of 2.453(14) solar masses. Given the known mass function, the pulsar mass has to be 0.96 solar masses, implying that it is a heavy white...

  14. Absolute Dimensions of the Eccentric Eclipsing Binary V541 Cygni

    Science.gov (United States)

    Torres, Guillermo; McGruder, Chima D.; Siverd, Robert J.; Rodriguez, Joseph E.; Pepper, Joshua; Stevens, Daniel J.; Stassun, Keivan G.; Lund, Michael B.; James, David

    2017-02-01

    We report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541 Cyg (P = 15.34 days, e = 0.468). Using these observations together with existing measurements, we determine the component masses and radii to better than 1% precision: {M}1={2.335}-0.013+0.017 {M}ȯ , {M}2={2.260}-0.013+0.016 {M}ȯ , {R}1={1.859}-0.009+0.012 {R}ȯ , and {R}2={1.808}-0.013+0.015 {R}ȯ . The nearly identical B9.5 stars have estimated effective temperatures of 10650 ± 200 K and 10350 ± 200 K. A comparison of these properties with current stellar evolution models shows excellent agreement at an age of about 190 Myr and [Fe/H] ≈ ‑0.18. Both components are found to be rotating at the pseudo-synchronous rate. The system displays a slow periastron advance that is dominated by general relativity (GR), and has previously been claimed to be slower than predicted by theory. Our new measurement, \\dot{ω }={0.859}-0.017+0.042 deg century‑1, has an 88% contribution from GR and agrees with the expected rate within the uncertainties. We also clarify the use of the gravity darkening coefficients in the light-curve fitting Eclipsing Binary Orbit Program (EBOP), a version of which we use here.

  15. The repeated bout effect of eccentric exercise is not associated with changes in voluntary activation.

    Science.gov (United States)

    Kamandulis, Sigitas; Skurvydas, Albertas; Brazaitis, Marius; Skikas, Laimutis; Duchateau, Jacques

    2010-04-01

    The aim of this study was to compare the possible changes in muscle activation level between a first and second bout of damaging eccentric exercise performed at 2 weeks interval (i.e. repeated bout effect). To that purpose, ten physically active males took part in this study. The eccentric exercise consisted of 10 sets of 12 maximal voluntary contractions (MVC) produced by the knee extensors during movements performed at a constant speed of 160 degrees s(-1). Changes in voluntary and electrically evoked torque in concentric and/or isometric conditions were assessed at the following time points: pre-exercise, and 2 min, 1 and 24 h after each eccentric exercise. At the same time points, voluntary activation was quantified by the superimposed electrical stimulation technique. Muscle soreness and plasma CK activity were measured within 48 h after the eccentric exercise. The results showed that the decrease in eccentric peak torque was linear throughout the exercise protocol. At the end of bouts 1 and 2, torque was significantly reduced by 27.7 +/- 9.1 and 23.4 +/- 11.2, respectively, with no difference between bouts (P > 0.05). At 24 h post-exercise, a lower reduction (P eccentric exercise appears to reduce muscle damage, but does not influence the level of voluntary activation.

  16. Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training.

    Science.gov (United States)

    Baroni, Bruno Manfredini; Rodrigues, Rodrigo; Freire, Bruno Bolla; Franke, Rodrigo de Azevedo; Geremia, Jeam Marcel; Vaz, Marco Aurélio

    2015-03-01

    Eccentric training has been popularized for physical conditioning and prevention/rehabilitation of musculoskeletal disorders, especially due to the expressive responses in terms of muscular strength gain. In view of evidence that low-level laser therapy (LLLT) is able to increase exercise performance and accelerate post-exercise recovery, the aim of this study was to verify the effect of LLLT on hypertrophy and strengthening of knee extensor muscles submitted to eccentric training. Thirty healthy male subjects were randomized into three groups: Control Group (CG), Training Group (TG) and Training + LLLT Group (TLG). CG received no intervention, while TG and TLG were engaged on an 8-week knee extensor isokinetic eccentric training program. Only subjects from TLG were treated with LLLT (wavelength = 810 nm; power output = 200 mW; total dosage = 240 J) before each training session. Knee extensor muscle thickness and peak torque were assessed through ultrasonography and isokinetic dynamometry, respectively. CG presented no changes in any variable throughout the study, while eccentric training led to significant increases in muscle thickness and peak torque in TG and TLG. Subjects from TLG reached significantly higher percent changes compared to subjects from TG for sum of muscles' thicknesses (15.4 vs. 9.4%), isometric peak torque (20.5 vs. 13.7%), and eccentric peak torque (32.2 vs. 20.0%). LLLT applied before eccentric training sessions seems to improve the hypertrophic response and muscular strength gain in healthy subjects.

  17. Neuromuscular and muscle-tendon system adaptations to isotonic and isokinetic eccentric exercise.

    Science.gov (United States)

    Guilhem, G; Cornu, C; Guével, A

    2010-06-01

    To present the properties of an eccentric contraction and compare neuromuscular and muscle-tendon system adaptations induced by isotonic and isokinetic eccentric trainings. An eccentric muscle contraction is characterized by the production of muscle force associated to a lengthening of the muscle-tendon system. This muscle solicitation can cause micro lesions followed by a regeneration process of the muscle-tendon system. Eccentric exercise is commonly used in functional rehabilitation for its positive effect on collagen synthesis but also for resistance training to increase muscle strength and muscle mass in athletes. Indeed, eccentric training stimulates muscle hypertrophy, increases the fascicle pennation angle, fascicles length and neural activation, thus inducing greater strength gains than concentric or isometric training programs. Eccentric exercise is commonly performed either against a constant external load (isotonic) or at constant velocity (isokinetic), inducing different mechanical constraints. These different mechanical constraints could induce structural and neural adaptive strategies specific to each type of exercise. The literature tends to show that isotonic mode leads to a greater strength gain than isokinetic mode. This observation could be explained by a greater neuromuscular activation after IT training. However, the specific muscle adaptations induced by each mode remain difficult to determine due to the lack of standardized, comparative studies. 2010 Elsevier Masson SAS. All rights reserved.

  18. 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 < 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. PMID:26649058

  19. 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.

  20. Influence of acute eccentric exercise on the H:Q ratio.

    Science.gov (United States)

    Thompson, B J; Smith, D B; Sobolewski, E J; Fiddler, R E; Everett, L; Klufa, J L; Ryan, E D

    2011-12-01

    The purpose of the present study was to examine the effects of an acute bout of eccentric exercise on maximal isokinetic concentric peak torque (PT) of the leg flexors and extensors and the hamstrings-to-quadriceps (H:Q) strength ratio. Sixteen male (mean±SD: age=20.9±2 years; stature=177.0±4.4 cm; mass=76.8±10.0 kg) volunteers performed maximal, concentric isokinetic leg extension and flexion muscle actions at 60°·sec - 1 before and after (24-72 h) a bout of eccentric exercise. The eccentric exercise protocol consisted of 4 sets of 10 repetitions for the leg press, leg extension, and leg curl exercises at 120% of the concentric one repetition maximum (1-RM). The results indicated that the acute eccentric exercise protocol resulted in a significant (Pexercise. However, the H:Q ratios were unaltered by the eccentric exercise protocol. These findings suggest that an acute bout of eccentric exercise utilizing both multi - and single - joint dynamic constant external resistance (DCER) exercises results in similar decreases in maximal isokinetic strength of the leg flexors and extensors, but does not alter the H:Q ratio. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Neuromuscular responses to mild-muscle damaging eccentric exercise in a low glycogen state.

    Science.gov (United States)

    Gavin, James P; Myers, Stephen D; Willems, Mark E T

    2015-02-01

    The aim of this study was to examine the effect of low muscle glycogen on the neuromuscular responses to maximal eccentric contractions. Fourteen healthy men (22 ± 3 years) performed single-leg cycling (20 min at ~75% maximal oxygen uptake (V̇O2 max); eight 90 s sprints at a 1:1 work-to-rest ratio (5% decrements from 90% to 55% V̇O2 max until exhaustion) the evening before 100 eccentric (1.57 rads(-1)) with reduced (RED) and normal glycogen (NORM). Neuromuscular responses were measured during and up to 48 h after with maximal voluntary and involuntary (twitch, 20 Hz and 50 Hz) isometric contractions. During eccentric contractions, peak torque decreased (RED: -16.1 ± 2.5%; NORM: -6.2 ± 5.1%) and EMG frequency increased according to muscle length. EMG activity decreased for RED only. After eccentric contractions, maximal isometric force was reduced up to 24h for NORM (-13.5 ± 5.8%) and 48 h for RED (-7.4 ± 10.9%). Twelve hours after eccentric contractions, twitch force and the 20:50 Hz ratio were decreased for RED but not for NORM. Immediate involuntary with prolonged voluntary force loss suggests that reduced glycogen is associated with increased susceptibility to mild muscle-damaging eccentric exercise with contributions of peripheral and central mechanisms to be different during recovery. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Eccentric exercise in aging and diseased skeletal muscle: good or bad?

    Science.gov (United States)

    Lovering, Richard M; Brooks, Susan V

    2014-06-01

    Evidence is accumulating regarding the benefits of exercise in people who are more susceptible to injury, such as the elderly, or those with a neuromuscular disease, for example Duchenne muscular dystrophy (DMD). There appears to be a consensus that exercise can be safely performed in aging and diseased muscles, but the role of eccentric exercise is not as clear. Eccentric (lengthening) contractions have risks and benefits. Eccentric contractions are commonly performed on a daily basis, and high-force voluntary eccentric contractions are often employed in strength training paradigms with excellent results; however, high-force eccentric contractions are also linked to muscle damage. This minireview examines the benefits and safety issues of using eccentric exercise in at-risk populations. A common recommendation for all individuals is difficult to achieve, and guidelines are still being established. Some form of exercise is generally recommended with aging and even with diseased muscles, but the prescription (frequency, intensity, and duration) and type (resistance vs. aerobic) of exercise requires personal attention, as there is great diversity in the functional level and comorbidities in the elderly and those with neuromuscular disease. Copyright © 2014 the American Physiological Society.

  3. 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

  4. Relationships between muscle power output using the stretch-shortening cycle and eccentric maximum strength.

    Science.gov (United States)

    Miyaguchi, Kazuyoshi; Demura, Shinichi

    2008-11-01

    This study aimed to examine the relationships between muscle power output using the stretch-shortening cycle (SSC) and eccentric maximum strength under elbow flexion. Eighteen young adult males pulled up a constant light load (2 kg) by ballistic elbow flexion under the following two preliminary conditions: 1) the static relaxed muscle state (SR condition), and 2) using the SSC with countermovement (SSC condition).Muscle power was determined from the product of the pulling velocity and the load mass by a power measurement instrument that adopted the weight-loading method. We assumed the pulling velocity to be the subject's muscle power parameters as a matter of convenience, because we used a constant load. The following two parameters were selected in reference to a previous study: 1) peak velocity (m x s(-1)) (peak power) and 2) 0.1-second velocity during concentric contraction (m x s(-1)) (initial power). Eccentric maximum strength by elbow flexion was measured by a handheld dynamometer.Initial power produced in the SSC condition was significantly larger than that in the SR condition. Eccentric maximum strength showed a significant and high correlation (r = 0.70) with peak power in the SSC condition but not in the SR condition. Eccentric maximum strength showed insignificant correlations with initial power in both conditions. In conclusion, it was suggested that eccentric maximum strength is associated with peak power in the SSC condition, but the contribution of the eccentric maximum strength to the SSC potentiation (initial power) may be low.

  5. "Beyond the pale of ordinary criticism": eccentricity and the fossil books of Thomas Hawkins.

    Science.gov (United States)

    Carroll, Victoria

    2007-06-01

    Thomas Hawkins wrote two books about his extraordinary collection of fossil reptiles: Memoirs of Ichthyosauri and Plesiosauri (1834) and The Book of the Great Sea-Dragons (1840). When contemporary readers explicitly labeled these books "eccentric," they were making use of a new discourse that aimed to make sense of phenomena that appeared to transgress the boundaries of an increasingly ordered and structured world. Some modern-day commentators have dismissed Hawkins's books because of their perceived eccentricities. This essay, by contrast, uses techniques of close reading and reception analysis to investigate them precisely as specimens of "eccentric" literature. It argues that, like other eccentric phenomena, the books were perceived to be liminal--they were felt to undermine the generic boundaries that governed the production and interpretation of the different kinds of literary work. Eccentricity as a social and cultural phenomenon has received surprisingly little attention from scholars until very recently. Through analyzing and contextualizing Hawkins's books, and the varied responses they provoked, this essay aims to contribute to our understanding both of eccentricity and of the generic conventions shaping varieties of scientific writing in the nineteenth century and beyond.

  6. Interacting Binaries with Eccentric Orbits II. Secular Orbital Evolution Due To Non-Conservative Mass Transfer

    CERN Document Server

    Sepinsky, J F; Kalogera, V; Rasio, F A

    2009-01-01

    We investigate the secular evolution of the orbital semi-major axis and eccentricity due to mass transfer in eccentric binaries, allowing for both mass and angular momentum loss from the system. Adopting a delta function mass transfer rate at the periastron of the binary orbit, we find that, depending on the initial binary properties at the onset of mass transfer, the orbital semi-major axis and eccentricity can either increase or decrease at a rate linearly proportional to the magnitude of the mass transfer rate at periastron. The range of initial binary mass ratios and eccentricities that leads to increasing orbital semi-major axes and eccentricities broadens with increasing degrees of mass loss from the system and narrows with increasing orbital angular momentum loss from the binary. Comparison with tidal evolution timescales shows that the usual assumption of rapid circularization at the onset of mass transfer in eccentric binaries is not justified, irrespective of the degree of systemic mass and angular ...

  7. 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.

  8. 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.

  9. Searching for gravitational-wave signals emitted by eccentric compact binaries using a non-eccentric template bank: implications for ground-based detectors

    CERN Document Server

    Cokelaer, T

    2009-01-01

    Most of the inspiralling compact binaries are expected to be circularized by the time their gravitational-wave signals enter the frequency band of ground-based detectors such as LIGO or VIRGO. However, it is not excluded that some of these binaries might still possess a significant eccentricity at a few tens of hertz. Despite this possibility, current search pipelines based on matched filtering techniques consider only non-eccentric templates. The effect of such an approximation on the loss of signal-to-noise ratio (SNR) has been investigated by Martel and Poisson (1999 Phys. Rev. D 60 124008) in the context of initial LIGO detector. They ascertained that non-eccentric templates will be successful at detecting eccentric signals. We revisit their work by incorporating current and future ground-based detectors and precisely quantify the exact loss of SNR. In order to be more faithful to an actual search, we maximized the SNR over a template bank, whose minimal match is set to 95%. PACS numbers: 02.70.-c, 07.05....

  10. Determining the Eccentricity of the Moon's Orbit without a Telescope

    Science.gov (United States)

    Krisciunas, Kevin

    2010-01-01

    Ancient Greek astronomers knew that Moon's distance from the Earth was not constant. Ptolemy's model of the Moon's motion implied that the Moon ranged in distance from 33 to 64 Earth radii. This implied that its angular size ranged nearly a factor of two. Tycho Brahe's model of the Moon's motion implied a smaller distance range, some ±3 percent at syzygy. However, the ancient and Renaissance astronomers are notably silent on the subject of measuring the angular size of the Moon as a check on the implied range of distance from their models of the position of the Moon. Using a quarter-inch hole in a piece of cardboard that slides along a yardstick, we show that pre-telescopic astronomers could have measured an accurate mean value of the angular size of the Moon, and that they could have determined a reasonably accurate value of the eccentricity of the Moon's orbit. The principal calibration for each observer is to measure the apparent angular diameter of a 91 mm disk viewed at a distance of 10 meters, giving a true angular size of 31.3 arcmin (the Moon's mean angular size). Because the sighting hole is not much bigger than the size of one's pupil, each observer obtains a personal correction factor with which to scale the raw measures. If one takes data over the course of 7 lunations (7.5 anomalistic months), any systematic errors which are a function of phase should even out over the course of the observations. We find that the random error of an individual observation of ±0.8 arcmin can be achieved.

  11. 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

  12. The Effect of the Rotor Static Eccentricity on the Electro-Mechanical Coupled Characteristics of the Motorized Spindle

    Directory of Open Access Journals (Sweden)

    Wu Zaixin

    2016-01-01

    Full Text Available High-speed motorized spindle is a multi-variable, non-linear and strong coupling system. The rotor static eccentricity is inevitable because of machining or assembling error. The rotor static eccentricities have an important effect on the electromechanical coupled characteristics of the motorized spindle. In this paper, the electromechanical coupled mathematical model of the motorized spindle was set up. The mathematical model includes mechanical and electrical equation. The mechanical and electrical equation is built up by the variational principle. Furthermore, the inductance parameters without the rotor static eccentricity and the inductance parameters with rotor static eccentricity have been calculated by the winding function method and the high speed motorized spindle was simulated. The result show that the rotor static eccentricity can delay the starting process of the motorized spindle, and at steady state, the rotor circuit currents are still large because of the rotor static eccentricity.

  13. Controlling the Eccentricity of Polar Lunar Orbits with Low-Thrust Propulsion

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    O. C. Winter

    2009-01-01

    Full Text Available It is well known that lunar satellites in polar orbits suffer a high increase on the eccentricity due to the gravitational perturbation of the Earth. That effect is a natural consequence of the Lidov-Kozai resonance. The final fate of such satellites is the collision with the Moon. Therefore, the control of the orbital eccentricity leads to the control of the satellite's lifetime. In the present work we study this problem and introduce an approach in order to keep the orbital eccentricity of the satellite at low values. The whole work was made considering two systems: the 3-body problem, Moon-Earth-satellite, and the 4-body problem, Moon-Earth-Sun-satellite. First, we simulated the systems considering a satellite with initial eccentricity equals to 0.0001 and a range of initial altitudes between 100 km and 5000 km. In such simulations we followed the evolution of the satellite's eccentricity. We also obtained an empirical expression for the length of time needed to occur the collision with the Moon as a function of the initial altitude. The results found for the 3-body model were not significantly different from those found for the 4-body model. Secondly, using low-thrust propulsion, we introduced a correction of the eccentricity every time it reached the value 0.05. These simulations were made considering a set of different thrust values, from 0.1 N up to 0.4 N which can be obtained by using Hall Plasma Thrusters. In each run we measured the length of time, needed to correct the eccentricity value (from e=0.04 to e=0.05. From these results we obtained empirical expressions of this time as a function of the initial altitude and as a function of the thrust value.

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

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    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.

  15. Strength gain through eccentric isotonic training without changes in clinical signs or blood markers.

    Science.gov (United States)

    Alves, Thâmara; Guarnier, Flávia A; Campoy, Fernanda A S; Gois, Mariana O; Albuquerque, Maíra C; Seraphim, Patrícia M; Netto, Jayme; Vanderlei, Luiz Carlos Marques; Padovani, Carlos R; Cecchini, Rubens; Pastre, Carlos Marcelo

    2013-11-21

    Localized exercises are widely used in rehabilitation processes. The predominant options are exercises with an emphasis on either concentric or eccentric contractions. Eccentric exercises promote greater strength gains compared to classical concentric stimuli, but can cause muscle damage. The aim of present study was to compare strength training composed of 10 sessions with progressive loads between groups with a predominance of concentric versus eccentric contraction through an analysis of isotonic strength, pressure pain threshold, creatine kinase, tumor necrosis factor-alpha and cortisol. One hundred twenty male subjects were divided into four groups: C1 and E1--single session of maximum strength with emphasis on concentric and eccentric contraction, respectively; C10 and E10--10 sessions with progressive loads from 80% to maximum strength with emphasis on concentric and eccentric contraction, respectively. Isotonic strength increased by 10% in E10 following the ten training sessions. C1 and E1 exhibited a lower pressure pain threshold 48 hours after the sessions in comparison to C10 and E10, respectively. Creatine kinase was increased in C1 in comparison to baseline, with significant differences (p ≤ 0.05) in comparison to E1 at 48 and 96 hours as well as C10 at 48, 72 and 96 hours. No significant differences were found in TNF-α or cortisol among the groups or evaluation times. Eccentric contraction training promotes functional adaptation. Moreover, both concentric and eccentric contraction training have a protective effect on the muscle in relation to a single session of maximum strength exercise. RBR-75scwh.

  16. The Effects of K(+) Channel Blockade on Eccentric and Isotonic Twitch and Fatiguing Contractions in situ.

    Science.gov (United States)

    van Lunteren, Erik; Moyer, Michelle

    2012-01-01

    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 ∼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 6 mm/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.

  17. The Effects of K+ Channel Blockade on Eccentric and Isotonic Twitch and Fatiguing Contractions in situ

    Science.gov (United States)

    van Lunteren, Erik; Moyer, Michelle

    2012-01-01

    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 ∼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 6 mm/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. PMID:23060809

  18. 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.

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

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    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

  20. Changes in the mechanical properties of human and amphibian muscle after eccentric exercise.

    Science.gov (United States)

    Jones, C; Allen, T; Talbot, J; Morgan, D L; Proske, U

    1997-01-01

    Following a series of eccentric contractions, that is stretching of the muscle while generating active tension, the length-tension relationship of isolated amphibian muscle has been shown to shift towards longer muscle length (Katz 1939; Wood et al. 1993). Here we report observations of electrically stimulated ankle extensor muscles of nine human subjects, demonstrating a similar shift in optimum angle for torque generation [3.9 (1.5) degrees] following exercise on an inclined treadmill that involved eccentric contractions in one leg. (All values are means with the SEMs in parentheses). The shift in the unexercised, control leg was significantly less [mean 0.4 (0.7) degree P post-exercise, while torque took a week to recover. A similar shift in optimum length [12 (1.3)% of rest length] was obtained for five toad (Bufo marinus) sartorius muscles subjected to 25 eccentric contractions. Isometrically contracted control muscles showed a smaller shift [3.5 (1.6)%, n = 5]. Accompanying the shift was a drop in tension of 46 (3)% after the eccentric contractions [control isometric, 23 (6)%, P < 0.0001]. By 5 h after the eccentric contractions the shift had returned to control values, while tension had not recovered. When viewed with an electron microscope, sartorius muscles fixed immediately after the eccentric contractions exhibited many small, and a few larger, regions of myofilament disruption. In muscles fixed 5 h after the contractions, no small regions of disruption were visible, and the number of large regions was no greater than in those muscles fixed immediately after the eccentric contractions. These disruptions are interpreted as the cause of the shift in length-tension relationship.

  1. The effects of eccentricities on the fracture of off-axis fiber composites. [carbon fiber reinforced plastics

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    Finite element analyses were performed to investigate theoretically the effects of in-plane and out-of-plane eccentricities, bending or twisting, and thickness nonuniformity on the axial stress and strain variations across the width of off-axis specimens. The results are compared with measured data and are also used to assess the effects of these eccentricities on the fracture stress of off-axis fiber composites. Guidelines for detecting and minimizing the presence of eccentricities are described.

  2. 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.

  3. Effects of concentric and repeated eccentric exercise on muscle damage and calpain-calpastatin gene expression in human skeletal muscle

    DEFF Research Database (Denmark)

    Vissing, K.; Overgaard, K.; Nedergaard, A.

    2008-01-01

    The purpose of this study was to compare the responsiveness of changes in Ca2+-content and calpain-calpastatin gene expression to concentric and eccentric single-bout and repeated exercise. An exercise group (n = 14) performed two bouts of bench-stepping exercise with 8 weeks between exercise bouts...... for muscle Ca2+-content and mRNA levels for calpain isoforms and calpastatin. Exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P ... eccentric exercise bout (P eccentric exercise 24 h post-exercise (P

  4. 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

  5. Surgical treatment compared with eccentric training for patellar tendinopathy (Jumper's Knee). A randomized, controlled trial.

    Science.gov (United States)

    Bahr, Roald; Fossan, Bjørn; Løken, Sverre; Engebretsen, Lars

    2006-08-01

    Although the surgical treatment of patellar tendinopathy (jumper's knee) is a common procedure, there have been no randomized, controlled trials comparing this treatment with forms of nonoperative treatment. The purpose of the present study was to compare the outcome of open patellar tenotomy with that of eccentric strength training in patients with patellar tendinopathy. Thirty-five patients (forty knees) who had been referred for the treatment of grade-IIIB patellar tendinopathy were randomized to surgical treatment (twenty knees) or eccentric strength training (twenty knees). The eccentric training group performed squats on a 25 degrees decline board as a home exercise program (with three sets of fifteen repetitions being performed twice daily) for a twelve-week intervention period. In the surgical treatment group, the abnormal tissue was removed by means of a wedge-shaped full-thickness excision, followed by a structured rehabilitation program with gradual progression to eccentric training. The primary outcome measure was the VISA (Victorian Institute of Sport Assessment) score (possible range, 0 to 100), which was calculated on the basis of answers to a symptom-based questionnaire that was developed specifically for patellar tendinopathy. The patients were evaluated after three, six, and twelve months of follow-up. There was no difference between the groups with regard to the VISA score during the twelve-month follow-up period, but both groups had improvement (p knees had no symptoms, twelve had improvement but were still symptomatic, two were unchanged, and one was worse after twelve months (p = 0.49 compared with the eccentric training group). In the eccentric training group, five knees did not respond to treatment and underwent secondary surgery after three to six months. Of the remaining fifteen knees in the eccentric training group, seven had no symptoms and eight had improvement but were still symptomatic after twelve months. No advantage was

  6. An objective statistical test for eccentricity forcing of Oligo-Miocene climate

    Science.gov (United States)

    Proistosescu, C.; Huybers, P.; Maloof, A. C.

    2008-12-01

    We seek a maximally objective test for the presence of orbital features in Oligocene and Miocene δ18O records from marine sediments. Changes in Earth's orbital eccentricity are thought to be an important control on the long term variability of climate during the Oligocene and Miocene Epochs. However, such an important control from eccentricity is surprising because eccentricity has relatively little influence on Earth's annual average insolation budget. Nevertheless, if significant eccentricity variability is present, it would provide important insight into the operation of the climate system at long timescales. Here we use previously published data, but using a chronology which is initially independent of orbital assumptions, to test for the presence of eccentricity period variability in the Oligocene/Miocene sediment records. In contrast to the sawtooth climate record of the Pleistocene, the Oligocene and Miocene climate record appears smooth and symmetric and does not reset itself every hundred thousand years. This smooth variation, as well as the time interval spanning many eccentricity periods makes Oligocene and Miocene paleorecords very suitable for evaluating the importance of eccentricity forcing. First, we construct time scales depending only upon the ages of geomagnetic reversals with intervening ages linearly interpolated with depth. Such a single age-depth relationship is, however, too uncertain to assess whether orbital features are present. Thus, we construct a second depth-derived age-model by averaging ages across multiple sediment cores which have, at least partly, independent accumulation rate histories. But ages are still too uncertain to permit unambiguous detection of orbital variability. Thus we employ limited tuning assumptions and measure the degree by orbital period variability increases using spectral power estimates. By tuning we know that we are biasing the record toward showing orbital variations, but we account for this bias in our

  7. 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

  8. 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, experimental

  9. Reduced short-interval intracortical inhibition after eccentric muscle damage in human elbow flexor muscles.

    Science.gov (United States)

    Pitman, Bradley M; Semmler, John G

    2012-09-01

    The purpose of this study was to use paired-pulse transcranial magnetic stimulation (TMS) to examine the effect of eccentric exercise on short-interval intracortical inhibition (SICI) after damage to elbow flexor muscles. Nine young (22.5 ± 0.6 yr; mean ± SD) male subjects performed maximal eccentric exercise of the elbow flexor muscles until maximal voluntary contraction (MVC) force was reduced by ∼40%. TMS was performed before, 2 h after, and 2 days after exercise under Rest and Active (5% MVC) conditions with motor-evoked potentials (MEPs) recorded from the biceps brachii (BB) muscle. Peripheral electrical stimulation of the brachial plexus was used to assess maximal M-waves, and paired-pulse TMS with a 3-ms interstimulus interval was used to assess changes in SICI at each time point. The eccentric exercise resulted in a 34% decline in strength (P muscle strength (27%, P muscle soreness (P muscle damage. When the test MEP amplitudes were matched between sessions, we found that SICI was reduced by 27% in resting and 23% in active BB muscle 2 h after exercise. SICI recovered 2 days after exercise when muscle pain and soreness were present, suggesting that delayed onset muscle soreness from eccentric exercise does not influence SICI. The change in SICI observed 2 h after exercise suggests that eccentric muscle damage has widespread effects throughout the motor system that likely includes changes in motor cortex.

  10. Effects of Differing Dosages of Pomegranate Juice Supplementation after Eccentric Exercise

    Directory of Open Access Journals (Sweden)

    Daniel R. Machin

    2014-01-01

    Full Text Available Dietary supplementation with pomegranate juice improves isometric strength recovery after unaccustomed eccentric exercise. The purpose of this study was to determine if there is a dose response effect of pomegranate juice supplementation after eccentric exercise isometric strength recovery. Forty-five nonresistance trained, recreationally active men were assigned once-daily pomegranate juice, twice-daily pomegranate juice, or placebo supplementation. On day four of supplementation, 20 min of downhill running and 40 maximal eccentric elbow flexion repetitions were performed. Isometric knee extensor and elbow flexor strength, muscular soreness, and serum myoglobin concentrations were measured prior to exercise and 2, 24, 48, 72, and 96 h after exercise. Throughout the postexercise time period, while isometric knee extensor and elbow flexor strength were similar between once-daily and twice-daily pomegranate juice supplementation groups, isometric strength was significantly higher in pomegranate juice groups than placebo. Knee extensor soreness, elbow flexor soreness, and myoglobin increased in response to exercise but were similar between groups. It is apparent that pomegranate juice supplementation improves strength recovery in leg and arm muscles following eccentric exercise; however, no dose response effect was present. We conclude that once-daily pomegranate juice supplementation is not different from twice-daily supplementation in regards to strength recovery after eccentric exercise.

  11. Effects of Low-Level Laser Therapy and Eccentric Exercises in the Treatment of Patellar Tendinopathy

    Directory of Open Access Journals (Sweden)

    Xiao-Guang Liu

    2014-01-01

    Full Text Available The study aims to investigate if low-level laser therapy (LLLT combined with eccentric exercises could more effectively treat patellar tendinopathy than LLLT alone and eccentric exercises alone. Twenty-one patients with patellar tendinopathy were randomized to three groups: laser alone, exercise alone, or laser plus exercise, with seven in each group. Laser irradiations were administered at the inferior pole of the patella and the two acupoints of Extra 36 (Xiyan with the intensity of 1592 mW/cm2. Eccentric training program consisted of three sets of 15 repetitions of unilateral squat on level ground. All patients received six treatments per week for four weeks. Knee pain and function and quadriceps muscle strength and endurance were evaluated at baseline and the end of treatment. After the 4-week intervention, all groups showed significant improvements in all the outcomes (P<0.01. The laser + exercise group had significantly greater improvements in all the outcomes than the other two groups (P<0.05, except nonsignificant difference in pain relief between the laser + exercise group and the laser group. In conclusion, LLLT combined with eccentric exercises is superior to LLLT alone and eccentric exercises alone to reduce pain and improve function in patients with patellar tendinopathy.

  12. Electromyographic analysis of an eccentric calf muscle exercise in persons with and without Achilles tendinopathy.

    Science.gov (United States)

    Reid, Duncan; McNair, Peter J; Johnson, Shelley; Potts, Geoff; Witvrouw, Erik; Mahieu, Nele

    2012-08-01

    To compare surface electromyographic (EMG) activity of the gastrocnemius and soleus muscles between persons with and without Achilles tendinopathy (AT) during an eccentric muscle exercise in different knee joint positions. Repeated measures design. Research laboratory. Participants (n = 18) diagnosed with AT and 18 control subjects were recruited. Gastrocnemius and soleus muscle activity was examined by surface (EMG) during extended and flexed knee joint conditions while performing the eccentric training technique. The EMG data were expressed as a percentage of a maximum voluntary contraction (MVC). EMG activity was notably higher (mean difference: 10%, effect size: 0.59) in those subjects with AT. Irrespective of the presence of AT, there was a significant interaction effect between muscle and joint position. The gastrocnemius muscle was significantly more active in the extended knee condition and soleus muscle activity was unchanged across joint positions. The results indicated that the presence of AT influenced calf muscle activity levels during performance of the eccentric exercise. There were differences in muscle activity during the extended and flexed knee conditions. This result does support performing Alfredson, Pietila, Jonsson, and Lorentzon (1998) eccentric exercise in an extended knee position but the specific effects of the knee flexed position on the Achilles tendon during eccentric exercise have yet to be determined, particularly in those with AT. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Effect of eccentric contraction on satellite cell activation in human vastus lateralis muscle.

    Science.gov (United States)

    Imaoka, Yoko; Kawai, Minako; Mori, Futoshi; Miyata, Hirofumi

    2015-09-01

    We compared the time-course of satellite cell (SC) activation between eccentric and concentric contractions in the vastus lateralis (VL) muscle after step exercise. Young adults participated in a 30-min step up/down exercise which mainly involved concentric contractions with the right VL muscle and eccentric contractions with the left VL muscle. The concentric and eccentric contraction phases of the VL muscles were identified by changes in the electromyogram (EMG) and knee joint angle. Biopsy samples were taken from both VL muscles at three time periods: before the exercise and 2 and 5 days after the exercise. We found that the numbers of SCs were significantly increased in the type IIa fibers of the left VL at 2 and 5 days after the exercise. The expression of both hepatocyte growth factor (HGF) and myogenic differentiation 1 (MyoD) mRNA had significantly increased in the left VL at 2 and 5 days after the exercise and in the right VL at 5 days after the exercise. The expression of transient receptor potential canonical (TRPC) 1 mRNA also increased in the left VL at 2 days after exercise. These results indicate that eccentric contraction can effectively activate SC proliferation for up to 5 days after exercise. Similar changes in HGF, MyoD and TRPC1 mRNA expression suggest that HGF/c-Met signal activation through cation influx has a major impact on skeletal muscle SC activation in response to eccentric exercise.

  14. The origin of the eccentricity of the hot Jupiter in CI Tau

    Science.gov (United States)

    Rosotti, G. P.; Booth, R. A.; Clarke, C. J.; Teyssandier, J.; Facchini, S.; Mustill, A. J.

    2017-01-01

    Following the recent discovery of the first radial velocity planet in a star still possessing a protoplanetary disc (CI Tau), we examine the origin of the planet's eccentricity (e ˜0.3). We show through long time-scale (105 orbits) simulations that the planetary eccentricity can be pumped by the disc, even when its local surface density is well below the threshold previously derived from short time-scale integrations. We show that the disc may be able to excite the planet's orbital eccentricity in <1 Myr for the system parameters of CI Tau. We also perform two-planet scattering experiments and show that alternatively the observed planet may plausibly have acquired its eccentricity through dynamical scattering of a migrating lower mass planet, which has either been ejected from the system or swallowed by the central star. In the latter case the present location and eccentricity of the observed planet can be recovered if it was previously stalled within the disc's magnetospheric cavity.

  15. Eccentricity Excitation and Apsidal Resonance Capture in the Planetary System Upsilon Andromedae

    CERN Document Server

    Chiang, E I

    2002-01-01

    The orbits of the outer two known planets orbiting Upsilon Andromedae are remarkably eccentric. Planet C possesses an orbital eccentricity of e1 = 0.253. For the more distant planet D, e2 = 0.308. Previous dynamical analyses strongly suggest that the two orbits are nearly co-planar and are trapped in an apsidal resonance in which the difference between their longitudes of periastron undergoes a bounded oscillation about 0 degrees. Here we elucidate the origin of these large eccentricities and of the apsidal alignment. Resonant interactions between a remnant circumstellar disk of gas lying exterior to the orbits of both planets can smoothly grow e2. Secular interactions between planets D and C can siphon off the eccentricity of the former to grow that of the latter. Externally amplifying e2 during the phase of the apsidal oscillation when e2/e1 is smallest drives the oscillation amplitude towards zero. Thus, the substantial eccentricity of planet C and the locking of orbital apsides are both consequences of ex...

  16. Eccentricity modulation of a close-in planet by a companion: Application to GJ 436 system

    Institute of Scientific and Technical Information of China (English)

    TONG Xiao; ZHOU JiLin

    2009-01-01

    GJ 436b is a Neptune-size planet with 23.2 Earth masses in an elliptical orbit of period 2.64 days and eccentricity 0.16. With a typical tidal dissipation factor (Q'~106) as that of a giant planet with convective envelope, its orbital circularization timescale under internal tidal dissipation is around 1 Ga, at least two times less than the stellar age (> 3 Ga). A plausible mechanism is that the eccentricity of GJ 436b is modulated by a planetary companion due to their mutual perturbation. Here we investigate this possi-bility from the dynamical viewpoint. A general method is given to predict the possible locations of the dynamically coupled companions, including nearby/distance non-resonant or mean motion resonance orbits with the first planet. Applying the method to GJ 436 system, we find it is very unlikely that the eccentricity of GJ 436b is maintained at the present location by a nearby/distance companion through secular perturbation or mean motion resonance. In fact, in all these simulated cases, GJ 436b will un-dergo eccentricity damp and orbital decay, leaving the present location within the stellar age. However, these results do not rule out the possible existence of planet companions in nearby/distance orbits, although they are not able to maintain the eccentricity of GJ 436b.

  17. Muscle fatigue experienced during maximal eccentric exercise is predictive of the plasma creatine kinase (CK) response.

    Science.gov (United States)

    Hody, S; Rogister, B; Leprince, P; Wang, F; Croisier, J-L

    2013-08-01

    Unaccustomed eccentric exercise may cause skeletal muscle damage with an increase in plasma creatine kinase (CK) activity. Although the wide variability among individuals in CK response to standardized lengthening contractions has been well described, the reasons underlying this phenomenon have not yet been understood. Therefore, this study investigated a possible correlation of the changes in muscle damage indirect markers after an eccentric exercise with the decline in muscle performance during the exercise. Twenty-seven healthy untrained male subjects performed three sets of 30 maximal isokinetic eccentric contractions of the knee extensors. The muscular work was recorded using an isokinetic dynamometer to assess muscle fatigue by means of various fatigue indices. Plasma CK activity, muscle soreness, and stiffness were measured before (pre) and one day after (post) exercise. The eccentric exercise bout induced significant changes of the three muscle damage indirect markers. Large inter-subject variability was observed for all criteria measured. More interestingly, the log (CK(post) /CK(pre)) and muscle stiffness appeared to be closely correlated with the relative work decrease (r = 0.84, r(2)  = 0.70 and r = 0.75, r(2)  = 0.56, respectively). This is the first study to propose that the muscle fatigue profile during maximal eccentric protocol could predict the magnitude of the symptoms associated with muscle damage in humans.

  18. TLR4-mediated blunting of inflammatory responses to eccentric exercise in young women.

    Science.gov (United States)

    Fernandez-Gonzalo, Rodrigo; De Paz, José A; Rodriguez-Miguelez, Paula; Cuevas, María J; González-Gallego, Javier

    2014-01-01

    This study assessed the inflammatory response mediated by the toll-like receptor 4 (TLR4) signaling pathway after acute eccentric exercise before and after an eccentric training program in women. Twenty women performed two acute eccentric bouts using a squat machine over a ~9 week interval. The training group (TG) carried out an eccentric training program during 6 weeks, while the control group (CG) did not follow any training. Protein content of markers involved in the TLR4-mediated activation of several nuclear transcription factors, such as nuclear factor κB (NF-κB), and interferon regulatory transcription factor 3 (IRF3), was analyzed. The inflammatory response after the first acute bout was similar between TG and CG, showing an upregulation of all the markers analyzed, with the exception of IRF3. After the second bout, the upregulation of TLR4 signaling pathway was blunted in TG, but not in CG, through both the myeloid differentiation factor 88- and toll/interleukin-1 receptor domain containing adapter inducing interferon-β-dependent pathways. These results highlight the role of the TLR4 in controlling the exercise-induced inflammatory response in young women. More importantly, these data suggest eccentric training may help to prevent TLR4 activation principally through NF-κB, and perhaps IRF3, downstream signaling in this population.

  19. Gender differences in fascicular lengthening during eccentric contractions: the role of the patella tendon stiffness.

    Science.gov (United States)

    Hicks, K M; Onambele-Pearson, G L; Winwood, K; Morse, C I

    2013-11-01

    Elastic tendons have been suggested to attenuate fascicle lengthening during eccentric contractions; however, there is no in vivo evidence to support this hypothesis. Therefore, the aim of this study was to determine whether patella tendon stiffness modulates vastus lateralis (VL) fascicle lengthening during eccentric contractions in males and females. Vastus lateralis and patella tendon properties were measured in males and females owing to previously reported intrinsic gender differences in tendon properties. During maximal voluntary eccentric knee extensions, VL fascicle lengthening and torque were recorded at every 10° (range of motion 20-90°). A significant correlation between maximal patella tendon stiffness and change in fascicle length (r=0.476, P=0.023) was observed. Similarly, there was a significant correlation between maximal Young's modulus and change in fascicle length (r=0.470, P=0.049). As expected, patella tendon stiffness and Young's modulus were significantly higher in males compared with females (Pmuscle-tendon unit elongation was estimated to be significantly greater in males compared with females (5.24 and 4.84 cm respectively). The significant difference in fascicle lengthening during eccentric contractions may be partly explained by the significantly higher patella tendon moment arm, patella tendon stiffness and Young's modulus found in males compared with females. The current study provides in vivo evidence to support the hypothesis that the tendon acts as a 'mechanical buffer' during eccentric contractions. © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  20. Effect of Alcohol Consumption on Recovery From Eccentric Exercise Induced Muscle Damage in Females.

    Science.gov (United States)

    McLeay, Yanita; Stannard, Stephen R; Mundel, Toby; Foskett, Andrew; Barnes, Matthew

    2017-04-01

    This study was designed to investigate the effects of alcohol consumption on recovery of muscle force when consumed immediately postexercise in young females. Eight young women completed 300 maximal eccentric actions of the quadriceps femoris muscle on an isokinetic dynamometer on two occasions in a randomized, cross-over design after which an alcoholic beverage (0.88g ethanol/kg body weight) or an iso-caloric placebo was consumed. Maximal isokinetic (concentric and eccentric) torque and isometric tension produced across the knee were measured in both the exercised and control leg predamage, 36 hr post, and 60 hr post damage. Venous blood creatine kinase (CK) activity and muscle soreness ratings were taken before damage and once per day to 60 hr post damage. Significant differences were observed between the exercised and control leg for maximal concentric, and eccentric torque and isometric tension (p eccentric torque. No main effects of treatment (alcohol) or interactions with Time × Leg or Leg × Treatment were observed. Perceived muscle soreness during box stepping and squatting showed significant time effects (p eccentric exercise-induced muscle damage does not affect recovery in the days following damage in females.

  1. TLR4-Mediated Blunting of Inflammatory Responses to Eccentric Exercise in Young Women

    Science.gov (United States)

    De Paz, José A.; Rodriguez-Miguelez, Paula; Cuevas, María J.

    2014-01-01

    This study assessed the inflammatory response mediated by the toll-like receptor 4 (TLR4) signaling pathway after acute eccentric exercise before and after an eccentric training program in women. Twenty women performed two acute eccentric bouts using a squat machine over a ~9 week interval. The training group (TG) carried out an eccentric training program during 6 weeks, while the control group (CG) did not follow any training. Protein content of markers involved in the TLR4-mediated activation of several nuclear transcription factors, such as nuclear factor κB (NF-κB), and interferon regulatory transcription factor 3 (IRF3), was analyzed. The inflammatory response after the first acute bout was similar between TG and CG, showing an upregulation of all the markers analyzed, with the exception of IRF3. After the second bout, the upregulation of TLR4 signaling pathway was blunted in TG, but not in CG, through both the myeloid differentiation factor 88- and toll/interleukin-1 receptor domain containing adapter inducing interferon-β-dependent pathways. These results highlight the role of the TLR4 in controlling the exercise-induced inflammatory response in young women. More importantly, these data suggest eccentric training may help to prevent TLR4 activation principally through NF-κB, and perhaps IRF3, downstream signaling in this population. PMID:25294957

  2. Repeated bouts of fast velocity eccentric contractions induce atrophy of gastrocnemius muscle in rats.

    Science.gov (United States)

    Ochi, Eisuke; Nosaka, Kazunori; Tsutaki, Arata; Kouzaki, Karina; Nakazato, Koichi

    2015-10-01

    One bout of exercise consisting of fast velocity eccentric contractions has been shown to increase muscle protein degradation in rats. The present study tested the hypothesis that muscle atrophy would be induced after four bouts of fast velocity eccentric contractions, but not after four bouts of slow velocity eccentric contractions. Male Wistar rats were randomly placed into 3 groups; fast (180°/s) velocity (180EC, n = 7), slow (30°/s) velocity eccentric exercise (30EC, n = 7), or sham-treatment group (control, n = 7). The 180EC and 30EC groups received 4 sessions of 4 sets of 5 eccentric contractions of triceps surae muscles by extending the ankle joint during evoked electrical stimulation of the muscles, and the control group had torque measures, every 2 days, and all rats were sacrificed 1 day after the fourth session. Medial and lateral gastrocnemius wet mass were 4-6 % smaller, cross-sectional area of medial gastrocnemius was 6-7% smaller, and isometric tetanic torque of triceps surae muscles was 36 % smaller (p contractions.

  3. Time-Course of Neuromuscular Changes during and after Maximal Eccentric Contractions.

    Science.gov (United States)

    Doguet, Valentin; Jubeau, Marc; Dorel, Sylvain; Couturier, Antoine; Lacourpaille, Lilian; Guével, Arnaud; Guilhem, Gaël

    2016-01-01

    This study tested the relationship between the magnitude of muscle damage and both central and peripheral modulations during and after eccentric contractions of plantar flexors. Eleven participants performed 10 sets of 30 maximal eccentric contractions of the plantar flexors at 45°·s(-1). Maximal voluntary torque, evoked torque (peripheral component) and voluntary activation (central component) were assessed before, during, immediately after (POST) and 48 h after (48 h) the eccentric exercise. Voluntary eccentric torque progressively decreased (up to -36%) concomitantly to a significant alteration of evoked torque (up to -34%) and voluntary activation (up to -13%) during the exercise. Voluntary isometric torque (-48 ± 7%), evoked torque (-41 ± 14%) and voluntary activation (-13 ± 11%) decreased at POST, but only voluntary isometric torque (-19 ± 6%) and evoked torque (-10 ± 18%) remained depressed at 48 h. Neither changes in voluntary activation nor evoked torque during the exercise were related to the magnitude of muscle damage markers, but the evoked torque decrement at 48 h was significantly correlated with the changes in voluntary activation (r = -0.71) and evoked torque (r = 0.77) at POST. Our findings show that neuromuscular responses observed during eccentric contractions were not associated with muscle damage. Conversely, central and peripheral impairments observed immediately after the exercise reflect the long-lasting reduction in force-generating capacity.

  4. Eccentric wrist extensor contractions and the force velocity relationship in muscle.

    Science.gov (United States)

    Walmsley, R P; Pearson, N; Stymiest, P

    1986-01-01

    The torque produced by the wrist extensors during maximal isometric and isokinetic eccentric contractions has been investigated. The torque produced by eccentric contractions was measured at three different velocities: 0.36, 0.93, and 1.64 cmlsec. The speeds of contraction were generated by a specially designed apparatus, consisting of a gear drive and an electric motor that would maintain its speed irrespective of the load applied. Tenison produced by the wrist extensors was measured using a load cell. The results indicated that eccentric contractions of the wrist extensors exceed those produced by isometric contractions. The force-velocity relationship during eccentric contractions was determined to be different from that during concentric contractions. Force values were found to increase as the velocity of eccentric contraction increased. No signficant effect of wrist joint angle on torque values was found, nor was there an interaction effect of velocity and joint angle. The implications for rehabilitation of these findings are outlined. J Orthop Sports Phys Ther 1986;8(6):288-293.

  5. Delayed Onset Vascular Stiffening Induced by Eccentric Resistance Exercise and Downhill Running.

    Science.gov (United States)

    Lin, Hsin-Fu; Chou, Chun-Chung; Cheng, Hao-Min; Tanaka, Hirofumi

    2017-07-01

    Eccentric exercise induces muscle stiffening and soreness as well as unfavorable changes in macrovascular function. We tested the hypothesis that systemic eccentric exercise could evoke greater arterial stiffening than local eccentric resistance exercise. Twenty healthy young men were randomly assigned into either the downhill running (DR) and the eccentric resistance exercise (RE) group followed by a crossover design with an exercise and sham control trial. Carotid-femoral pulse wave velocity (cfPWV), central hemodynamic measures, and biomarkers were obtained. Muscle soreness and plasma creatine kinase concentrations increased similarly after exercise in both groups. The cfPWV increased significantly at 48 hours post-exercise in both groups and remained elevated at 72 hours in DR. C-reactive protein (CRP) was elevated at 24 and 48 hours in DR, and 48 hours in RE. The increases in cfPWV were associated with the corresponding elevations in CRP in DR (r = 0.70, P < 0.05). There were no changes in arterial wave reflection measures. Both systemic and localized eccentric exercise modes induced delayed onset vascular stiffening with more prolonged changes observed in downhill running. The effect on arterial stiffening was associated, at least in part, with systemic inflammatory responses.

  6. Interacting Binaries with Eccentric Orbits. Secular Orbital Evolution Due To Conservative Mass Transfer

    CERN Document Server

    Sepinsky, J F; Kalogera, V; Rasio, F A

    2007-01-01

    We investigate the secular evolution of the orbital semi-major axis and eccentricity due to mass transfer in eccentric binaries, assuming conservation of total system mass and orbital angular momentum. Assuming a delta function mass transfer rate centered at periastron, we find rates of secular change of the orbital semi-major axis and eccentricity which are linearly proportional to the magnitude of the mass transfer rate at periastron. The rates can be positive as well as negative, so that the semi-major axis and eccentricity can increase as well as decrease in time. Adopting a delta-function mass-transfer rate of $10^{-9} M_\\sun {\\rm yr}^{-1}$ at periastron yields orbital evolution timescales ranging from a few Myr to a Hubble time or more, depending on the binary mass ratio and orbital eccentricity. Comparison with orbital evolution timescales due to dissipative tides furthermore shows that tides cannot, in all cases, circularize the orbit rapidly enough to justify the often adopted assumption of instantan...

  7. 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.

  8. 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.; Mora, A.; Bryden, G.; Danchi, William C.; Eiroa, C.; White, G. J.; Wolf, S.

    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

  9. Dynamic interaction between rotor and axially-magnetized passive magnetic bearing considering magnetic eccentricity

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar

    2014-01-01

    Passive magnetic bearings are known due to the excellent characteristics in terms of friction and no requirement of additional energy sources to work. However, passive magnetic bearings do not provide damping, are not stable and, depending on their design, may also introduce magnetic eccentricity....... Such magnetic eccentricities are generated by discrepancies in magnet fabrication. In this framework the main focus of the work is the theoretical as well as experimental investigation of the nonlinear dynamics of a rotor-bearing system with strong emphasis on the magnetic eccentricities and non......-linear stiffness. In this investigation passive magnetic bearings using axially- aligned neodymium cylinder magnets are investigated. The cylinder magnets are axially magnetised for rotor as well as bearings. Compared to bearings with radial magnetisation, the magnetic stiffness of axially-aligned bearings...

  10. The Highly-Eccentric Detached Eclipsing Binaries in ACVS and MACC

    CERN Document Server

    Shivvers, Isaac; Richards, Joseph W

    2014-01-01

    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 ASAS Classification Catalog. 106 detached eclipsing binaries with eccentricities greater than 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 6 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.

  11. Improved Relative-Entropy Method for Eccentricity Filtering in Roundness Measurement Based on Information Optimization

    Directory of Open Access Journals (Sweden)

    Xintao Xia

    2013-05-01

    Full Text Available In this study, we propose the improved relative-entropy of the ideal circle function to the measured information of the radius error of the workpiece surface to make an eccentricity filtering in roundness measurement. Along with a correct assessment for the parameters of the eccentricity filtering, the extracted information from the measured information is obtained by the minimization of the improved relative-entropy. The case studies show that the information optimization is characterized by decreasing the improved relative-entropy, the extracted information almost coincides with the real information, the improved relative-entropy has a strong immunity to the stochastic disturbance of the rough work piece-surface and the increase of the minimum of the improved relative-entropy counteracts the effect of the stochastic disturbance on the assessment for parameters in eccentricity filtering.

  12. Eccentric strengthening effect of hip-adductor training with elastic bands in soccer players

    DEFF Research Database (Denmark)

    Jensen, Jesper; Hölmich, Per; Bandholm, Thomas

    2014-01-01

    programme, including one hip-adduction exercise, on eccentric and isometric hip-adduction strength, using elastic bands as external load. METHODS: Thirty-four healthy, sub-elite soccer players, mean (±SD) age of 22.1 (±3.3) years, were randomised to either training or control. During the mid-season break...... sessions per week (weeks 7-8) with 3×8 RM. Eccentric hip-adduction (EHAD), isometric hip-adduction (IHAD) and isometric hip-abduction (IHAB) strength, and the IHAD/IHAB ratio were measured assessor-blinded preintervention and postintervention, using reliable hand-held dynamometry procedures. RESULTS...... or the IHAD/IHAB ratio existed (p>0.05). CONCLUSIONS: 8 weeks of hip-adduction strength training, using elastic bands, induce a relevant increase in eccentric hip-adduction strength in soccer players, and thus may have implications as a promising approach towards prevention of groin injuries in soccer....

  13. 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

    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...... of satellite cells 8 days after exercise. These results suggest that NSAIDs negatively affect satellite cell activity after unaccustomed eccentric exercise.......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...

  14. Methods of calculating the bearing capacity of eccentrically compressed concrete elements and suggestions for its improvement

    Directory of Open Access Journals (Sweden)

    Starishko Ivan Nikolaevich

    2014-03-01

    Full Text Available The proposed calculation method is specific in terms of determining the carrying capacity of eccentrically compressed concrete elements, in contrast to the calculation by error method, as in the existing regulations, where in the result of the calculation is not known what is the limit load the eccentric compression element can withstand. The proposed calculation method, the publication of which is expected in the next issue of the "Vestnik MGSU" the above mentioned shortcomings of the existing calculation methods, as well as the shortcomings listed in this article are eliminated, which results in the higher convergence of theoretical and experimental results of eccentrically compressed concrete elements strength and hence a high reliability of their operation.

  15. Associated decrements in rate of force development and neural drive after maximal eccentric exercise.

    Science.gov (United States)

    Farup, J; Rahbek, S K; Bjerre, J; de Paoli, F; Vissing, K

    2016-05-01

    The present study investigated the changes in contractile rate of force development (RFD) and the neural drive following a single bout of eccentric exercise. Twenty-four subjects performed 15 × 10 maximal isokinetic eccentric knee extensor contractions. Prior to and at 24, 48, 72, 96, and 168 h during post-exercise recovery, isometric RFD (30, 50 100, and 200 ms), normalized RFD [1/6,1/2, and 2/3 of maximal voluntary contraction (MVC)] and rate of electromyography rise (RER; 30, 50, and 75 ms) were measured. RFD decreased by 28-42% peaking at 48 h (P eccentric exercise. This association suggests that exercise-induced decrements in RFD can, in part, be explained decrements in neural drive. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. 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...

  17. eLISA eccentricity measurements as tracers of binary black hole formation

    Science.gov (United States)

    Nishizawa, Atsushi; Berti, Emanuele; Klein, Antoine; Sesana, Alberto

    2016-09-01

    Up to hundreds of black hole binaries individually resolvable by eLISA will coalesce in the Advanced LIGO and Virgo band within 10 yr, allowing for multiband gravitational wave observations. Binaries formed via dynamical interactions in dense star clusters are expected to have eccentricities e0˜10-3-10-1 at the frequencies f0=10-2 Hz where eLISA is most sensitive, while binaries formed in the field should have negligible eccentricity in both frequency bands. We estimate that eLISA should always be able to detect a nonzero e0 whenever e0≳10-2; if e0˜10-3, eLISA should detect nonzero eccentricity for a fraction ˜90 % (˜25 %) of binaries when the observation time is Tobs=5 (2) yr, respectively. Therefore eLISA observations of black hole binaries have the potential to distinguish between field and cluster formation scenarios.

  18. eLISA eccentricity measurements as tracers of binary black hole formation

    CERN Document Server

    Nishizawa, Atsushi; Klein, Antoine; Sesana, Alberto

    2016-01-01

    Up to hundreds of black hole binaries individually resolvable by eLISA will coalesce in the Advanced LIGO/Virgo band within ten years, allowing for multi-band gravitational wave observations. Binaries formed via dynamical interactions in dense star clusters are expected to have eccentricities $e_0\\sim 10^{-3}$-$10^{-1}$ at the frequencies $f_0=10^{-2}$ Hz where eLISA is most sensitive, while binaries formed in the field should have negligible eccentricity in both frequency bands. We estimate that eLISA should always be able to detect a nonzero $e_0$ whenever $e_0\\gtrsim 10^{-2}$; if $e_0\\sim 10^{-3}$, eLISA should detect nonzero eccentricity for a fraction $\\sim 90\\%$ ($\\sim 25\\%$) of binaries when the observation time is $T_{\\rm obs}=5$ ($2$) years, respectively. Therefore eLISA observations of BH binaries have the potential to distinguish between field and cluster formation scenarios.

  19. Pulsating red giant stars in eccentric binary systems discovered from Kepler space-based photometry

    CERN Document Server

    Beck, P G; Vos, J; Kallinger, T; Bloemen, S; Tkachenko, A; García, R A; Østensen, R H; Aerts, C; Kurtz, D W; De Ridder, J; Hekker, S; Pavlovski, K; Mathur, S; De Smedt, K; Derekas, A; Corsaro, E; Mosser, B; Van Winckel, H; Huber, D; Degroote, P; Davies, G R; Prša, A; Debosscher, J; Elsworth, Y; Nemeth, P; Siess, L; Schmid, V S; Pápics, P I; de Vries, B L; van Marle, A J; Marcos-Arenal, P; Lobel, A

    2013-01-01

    The unparalleled photometric data obtained by NASA's Kepler space telescope led to an improved understanding of red giant stars and binary stars. Seismology allows us to constrain the properties of red giants. In addition to eclipsing binaries, eccentric non-eclipsing binaries, exhibiting ellipsoidal modulations, have been detected with Kepler. We aim to study the properties of eccentric binary systems containing a red giant star and derive the parameters of the primary giant component. We apply asteroseismic techniques to determine masses and radii of the primary component of each system. For a selected target, light and radial velocity curve modelling techniques are applied to extract the parameters of the system. The effects of stellar on the binary system are studied. The paper presents the asteroseismic analysis of 18 pulsating red giants in eccentric binary systems, for which masses and radii were constrained. The orbital periods of these systems range from 20 to 440days. From radial velocity measuremen...

  20. The Application of Stereo Anti-eccentrically Teaching Methods in Traditional Chinese Qigong Course

    Directory of Open Access Journals (Sweden)

    Ai-Dong JI

    2014-04-01

    Full Text Available Objective: To explore the use of stereo anti-eccentrically Chinese qigong teaching mode. Method: To introduce the concrete steps of Qigong teaching methods from Qigong serious consequences,deeviation and the present teaching situation, the goal and significance of stereo anti-eccentrically qigong teaching methods etc. Result: In 2013, 6 classes and 498 students, only 23(4.61%)students appeared discomfort. Within a week the improvement of discomfort students is 16(69.56%),disappearance of discomfort students is 5(21.73%), two weeks later,disappeared discomfort students achieve 100%, have no  emergence of severe deviation, reached the safety of teaching purpose. Conclusion: Stereo anti-eccentrically Qigong teaching method can find the first hint of deviation and correct them in time, can improve the security of teaching. so it is worth spreading.

  1. 1D accretion discs around eccentric planets: observable near-infrared variability

    CERN Document Server

    Dunhill, Alex

    2014-01-01

    I present the results of 1D models of circumplanetary discs around planets on eccentric orbits. I use a classical viscous heating model to calculate emission fluxes at the wavelengths targeted by the NIRCam instrument on JWST, and compare the variability of this signal with the published NIRCam sensitivity specifications. This variability is theoretically detectable by JWST for a sufficiently viscous disc ($\\alpha \\sim 10^{-2}$) around a sufficiently eccentric planet ($e \\sim 0.1-0.2$) and if the circumplanetary disc accretes material from its parent disc at a rate $\\dot{M} \\gtrsim 10^{-7}\\, \\mathrm{M}_{\\odot}\\,\\mathrm{yr}^{-1}$. I discuss the limitations of the models used, and the implications of the result for probing the effectiveness of disc interactions for growing a planet's orbital eccentricity.

  2. Polar kicks and the spin period - eccentricity relation in double neutron stars

    CERN Document Server

    Willems, B; Kalogera, V; Belczynski, K

    2007-01-01

    We present results of a population synthesis study aimed at examining the role of spin-kick alignment in producing a correlation between the spin period of the first-born neutron star and the orbital eccentricity of observed double neutron star binaries in the Galactic disk. We find spin-kick alignment to be compatible with the observed correlation, but not to alleviate the requirements for low kick velocities suggested in previous population synthesis studies. Our results furthermore suggest low- and high-eccentricity systems may form through two distinct formation channels distinguished by the presence or absence of a stable mass transfer phase before the formation of the second neutron star. The presence of highly eccentric systems in the observed sample of double neutron stars may furthermore support the notion that neutron stars accrete matter when moving through the envelope of a giant companion.

  3. Impact of Orbital Eccentricity on the Detection of Transiting Extrasolar Planets

    CERN Document Server

    Burke, Christopher J

    2008-01-01

    For extrasolar planets with orbital periods, P>10 days, radial velocity surveys find non-circular orbital eccentricities are common, ~0.3. Future surveys for extrasolar planets using the transit technique will also have sensitivity to detect these longer period planets. Orbital eccentricity affects the detection of extrasolar planets using the transit technique in two opposing ways: an enhancement in the probability for the planet to transit near pericenter and a reduction in the detectability of the transit due to a shorter transit duration. For an eccentricity distribution matching the currently known extrasolar planets with P>10 day, the probability for the planet to transit is ~1.25 times higher than the equivalent circular orbit and the average transit duration is ~0.88 times shorter than the equivalent circular orbit. These two opposing effects nearly cancel for an idealized field transit survey with independent photometric measurements that are dominated by Poisson noise. The net effect is a modest ~4%...

  4. 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...... 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...

  5. 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. Physiol....... 79: 1338-1345, 1995). To study whether these changes affect insulin action, hindlimbs were perfused at three different insulin concentrations (0, 200, and 20,000 microU/ml) 2 days after one-legged eccentric contractions of the calf muscles. Compared with control, basal glucose transport was slightly...... velocity of glycogen synthase increased similarly with increasing insulin concentrations in Ecc- and control WG and RG. We conclude that insulin action on glucose transport but not glycogen synthase activity is impaired in perfused muscle exposed to prior eccentric contractions....

  6. Extreme Climate Variations from Milankovitch-like Eccentricity Oscillations in Extrasolar Planetary Systems

    CERN Document Server

    Spiegel, David S

    2010-01-01

    Although our solar system features predominantly circular orbits, the exoplanets discovered so far indicate that this is the exception rather than the rule. This could have crucial consequences for exoplanet climates, both because eccentric terrestrial exoplanets could have extreme seasonal variation, and because giant planets on eccentric orbits could excite Milankovitch-like variations of a potentially habitable terrestrial planet,\\"A\\^os eccentricity, on timescales of thousands-to-millions of years. A particularly interesting implication concerns the fact that the Earth is thought to have gone through at least one globally frozen, "snowball" state in the last billion years that it presumably exited after several million years of buildup of greenhouse gases when the ice-cover shut off the carbonate-silicate cycle. Water-rich extrasolar terrestrial planets with the capacity to host life might be at risk of falling into similar snowball states. Here we show that if a terrestrial planet has a giant companion o...

  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. Eccentric first post-Newtonian waveforms for compact binaries in frequency domain with Hansen coefficients

    CERN Document Server

    Mikóczi, Balázs; Vasúth, Mátyás

    2015-01-01

    The inspiral and merger of supermassive black hole binary systems with high orbital eccentricity are among the promising sources of the advanced gravitational wave observatories. In this paper we derive analytic ready-to-use first post-Newtonian eccentric waveform in Fourier domain with the use of Hansen coefficients. Introducing generic perturbations of celestial mechanics we have generalized the Hansen expansion to the first post-Newtonian order which are then used to express the waveforms. Taking into account the high eccentricity of the orbit leads to the appearance of secular terms in the waveform which are eliminated with the introduction of a phase shift. The waveforms have a systematic structure and as our main result these are expressed in a tabular form.

  9. 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.

  10. 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.

  11. Eccentric black hole mergers and zoom-whirl behavior from elliptic inspirals to hyperbolic encounters

    CERN Document Server

    Gold, Roman

    2012-01-01

    We perform a parameter study of non-spinning, equal and unequal mass black hole binaries on generic, eccentric orbits in numerical relativity. The linear momentum considered ranges from that of a circular orbit to ten times that value. We discuss the different manifestations of zoom-whirl behavior in the hyperbolic and the elliptic regime. The hyperbolic data set applies to dynamical capture scenarios (e.g. in globular clusters). Evolutions in the elliptic regime correspond to possible end states of supermassive black hole binaries. We spot zoom-whirl behavior for eccentricities as low as $e\\sim0.5$, i.e. within the expected range of eccentricities in massive black hole binaries from galaxy mergers and binaries near galactic centers. The resulting gravitational waveforms reveal a rich structure, which will effectively break degeneracies in parameter space improving parameter estimation.

  12. Combination of eccentric exercise and neuromuscular electrical stimulation to improve quadriceps function post-ACL reconstruction.

    Science.gov (United States)

    Lepley, Lindsey K; Wojtys, Edward M; Palmieri-Smith, Riann M

    2015-06-01

    Neuromuscular electrical stimulation (NMES) has been shown to reduce quadriceps activation failure (QAF), and eccentric exercise has been shown to lessen muscle atrophy post-ACL reconstruction. Given that these are two critical components of quadriceps strength, intervention combining these therapies may be effective at reinstituting quadriceps function post-reconstruction. Thus, the aim of this study was to evaluate the effectiveness of a combined NMES and eccentric exercise intervention to improve the recovery of quadriceps activation and strength post-reconstruction. Thirty-six individuals post-injury were placed into four treatment groups (N&E, NMES and eccentrics; E-only, eccentrics only; N-only, NMES-only; and STND, standard of care) and ten healthy controls participated. N&E and N-only received the NMES protocol 2× per week for the first 6 weeks post-reconstruction. N&E and E-only received the eccentric exercise protocol 2× per week beginning 6 weeks post-reconstruction. Quadriceps activation was assessed via the superimposed burst technique and quantified via the central activation ratio. Quadriceps strength was assessed via maximal voluntary isomeric contractions (Nm/kg). Data was gathered on three occasions: pre-operative, 12-weeks-post-surgery and at return-to-play. No differences in pre-operative measures existed (P>0.05). E-only recovered quadriceps activation better than N-only or STND (P0.05). Eccentric exercise was capable of restoring levels of quadriceps activation and strength that were similar to those of healthy adults and better than NMES alone. Level 3, Parallel longitudinal study. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Progressive Resistance Exercise with Eccentric Loading for the Management of Knee Osteoarthritis.

    Science.gov (United States)

    Hernandez, Haniel J; McIntosh, Valerie; Leland, Azadeh; Harris-Love, Michael O

    2015-01-01

    The patient was a 58-year-old African-American male with radiographic evidence of bilateral knee osteoarthritis (OA). He participated in a standardized 12-week eccentric strengthening program within a Veterans Affairs (VA) medical center. The use of an eccentric training paradigm may prove to be beneficial for older adults with knee OA since eccentric muscle actions are involved in the energy absorption at the knee joint during gait and controlled movement during stair descent. Furthermore, in comparison to standard muscle actions, eccentric muscle actions result in higher torque generation and a lower rate of oxygen consumption at a given level of perceived exertion. Therefore, this mode of progressive resistance exercise may be ideal for older adults. The patient completed an eccentric strengthening regimen for the knee flexors and extensors twice per week without an exacerbation of knee pain. Muscle morphology measures of the rectus femoris were measured using diagnostic ultrasound. Isokinetic measures of muscle peak torque were obtained at 60°/s and 180°/s. Functional performance was assessed using a physical performance battery and stair-step performance was assessed from the linear displacement of the center of gravity trajectories obtained with a force plate. Visual analog scale pain ratings and self-reported global disease status were also documented. Post-exercise assessments revealed improvements in sonographic muscle size and tissue composition estimates, peak knee extensor torque (ranging from 60 to 253%), functional performance, and global disease status. The patient exhibited improvements in muscle morphology, muscle strength, functional performance, pain, and global disease status after 12 weeks of an eccentric strengthening regimen. The intervention and outcomes featured in this case were feasible to implement within a VA medical center and merit further investigation.

  14. Acute alcohol consumption aggravates the decline in muscle performance following strenuous eccentric exercise.

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    Barnes, Matthew J; Mündel, Toby; Stannard, Stephen R

    2010-01-01

    This study investigated the effects of acute moderate alcohol intake on muscular performance during recovery from eccentric exercise-induced muscle damage. Eleven healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed a beverage containing 1g/kg bodyweight ethanol (as vodka and orange juice) (ALC). On another occasion they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed an isocaloric quantity of orange juice (OJ). Measurement of maximal isokinetic (concentric and eccentric) and isometric torque produced across the knee, plasma creatine kinase (CK) concentrations and muscle soreness were made before and at 36 and 60h following each exercise bout. All measures of muscle performance were significantly reduced at 36 and 60h post-exercise compared to pre-exercise measures (all peccentric contractions, respectively. However, peak strength loss was significantly greater in ALC with the same performance measures decreasing by 34%, 40% and 34%, respectively. Post-exercise plasma creatine kinase activity and ratings of muscle soreness were not different between conditions (both p>0.05). These results indicate that consumption of even moderate amounts of alcohol following eccentric-based exercise magnifies the normally observed losses in dynamic and static strength. Therefore, to minimise exercise related losses in muscle function and expedite recovery, participants in sports involving eccentric muscle work should avoid alcohol-containing beverages in the post-event period. Copyright (c) 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. Improvements in multi-joint leg function following chronic eccentric exercise.

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    Elmer, S; Hahn, S; McAllister, P; Leong, C; Martin, J

    2012-10-01

    Previous authors have reported that chronic eccentric cycling facilitates greater changes in multi-joint leg function (hopping frequency, maximum jumping height) compared with concentric cycling. Our purpose was to evaluate changes in leg spring stiffness and maximum power following eccentric and concentric cycling training. Twelve individuals performed either eccentric (n=6) or concentric (n=6) cycling for 7 weeks (3 sessions/week) while training duration progressively increased. Participants performed trials of submaximal hopping, maximal counter movement jumps, and maximal concentric cycling to evaluate leg spring stiffness, maximum jumping power, and maximum concentric cycling power respectively, before and 1 week following training. Total work during training did not differ between eccentric and concentric cycling (126 ± 15-728 ± 91 kJ vs 125 ± 10-787 ± 76 kJ). Following training, eccentric cycling exhibited greater changes in k(leg) and jumping P(max) compared with CON(cyc) (10 ± 3% vs -2 ± 4% and 7 ± 2% vs -2 ± 3%, respectively, P=0.05). Alterations in CON(cyc) P(max) did not differ between ECC(cyc) (1035 ± 142 vs 1030 ± 133 W) and CON(cyc) (1072 ± 98 vs 1081 ± 85 W). These data demonstrate that eccentric cycling is an effective method for improving leg spring stiffness and maximum power during multi-joint tasks that include stretch-shortening cycles. Improvements in leg spring stiffness and maximum power would be beneficial for both aging and athletic populations.

  16. Progressive Resistance Exercise with Eccentric Loading for the Management of Knee Osteoarthritis

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    Michael O Harris-Love

    2015-07-01

    Full Text Available Introduction: The patient was a 58-year-old African-American male with radiographic evidence of knee osteoarthritis. He participated in a standardized 12-week eccentric strengthening program within a VA medical center. Background: The use of an eccentric training paradigm may prove to be beneficial for older adults with knee osteoarthritis since eccentric muscle actions are involved in the energy absorption at the knee joint during gait and controlled movement during stair descent. Furthermore, in comparison to standard muscle actions, eccentric muscle actions result in higher torque generation and a lower rate of oxygen consumption at a given level of perceived exertion. Therefore, this mode of progressive resistance exercise may be ideal for older adults. Discussion: The patient completed an eccentric strengthening regimen for the knee flexors and extensors twice per week without an exacerbation of knee pain. Muscle morphology measures of the rectus femoris were measured using diagnostic ultrasound. Isokinetic measures of muscle peak torque were be obtained at 60°/s and 180°/s. Functional performance was assessed using a physical performance battery and stair step performance was assessed from the linear displacement of the center of gravity trajectories obtained with a force plate. Visual analogue scale pain ratings and self-reported global disease status were also documented. Post-exercise assessments revealed improvements in sonographic muscle size and tissue composition estimates, peak knee extensor torque (ranging from 60% to 253%, functional performance, and global disease status. Concluding Remarks: The patient exhibited improvements in muscle morphology, muscle strength, functional performance, pain, and global disease status after 12 weeks of an eccentric strengthening regimen. The intervention and outcomes featured in this case were feasible to implement within a VA medical center and merit further investigation.

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

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    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 knee extension 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.

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

    Science.gov (United States)

    Franchi, Martino V.; Reeves, Neil D.; Narici, Marco V.

    2017-01-01

    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. PMID:28725197

  19. Dissociated time course recovery between rate of force development and peak torque after eccentric exercise.

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    Molina, Renato; Denadai, Benedito S

    2012-05-01

    This study investigated the association between isokinetic peak torque (PT) of quadriceps and the corresponding peak rate of force development (peak RFD) during the recovery of eccentric exercise. Twelve untrained men (aged 21·7 ± 2·3 year) performed 100 maximal eccentric contractions for knee extensors (10 sets of 10 repetitions with a 2-min rest between each set) on isokinetic dynamometer. PT and peak RFD accessed by maximal isokinetic knee concentric contractions at 60° s(-1) were obtained before (baseline) and at 24 and 48 h after eccentric exercise. Indirect markers of muscle damage included delayed onset of muscle soreness (DOMS) and plasma creatine kinase (CK) activity. The eccentric exercise resulted in elevated DOMS and CK compared with baseline values. At 24 h, PT (-15·3%, P = 0·002) and peak RFD (-13·1%, P = 0·03) decreased significantly. At 48 h, PT (-7·9%, P = 0·002) was still decreased but peak RFD have returned to baseline values. Positive correlation was found between PT and peak RFD at baseline (r = 0·62, P = 0·02), 24 h (r = 0·99, P = 0·0001) and 48 h (r = 0·68, P = 0·01) after eccentric exercise. The magnitude of changes (%) in PT and peak RFD from baseline to 24 h (r = 0·68, P = 0·01) and from 24 to 48 h (r = 0·68, P = 0·01) were significantly correlated. It can be concluded that the muscle damage induced by the eccentric exercise affects differently the time course of PT and peak RFD recovery during isokinetic concentric contraction at 60° s(-1). During the recovery from exercise-induced muscle damage, PT and peak RFD are determined but not fully defined by shared putative physiological mechanisms. © 2011 The Authors. Clinical Physiology and Functional Imaging © 2011 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

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

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    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

  1. 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 (pexercise (lower in 5 of the 6 subjects at 7-8 days than at 2-3 days; pexercise 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.

  2. Pressure pain mapping of the wrist extensors after repeated eccentric exercise at high intensity.

    Science.gov (United States)

    Delfa de la Morena, José M; Samani, Afshin; Fernández-Carnero, Josué; Hansen, Ernst A; Madeleine, Pascal

    2013-11-01

    The purpose of this study was to investigate adaptation mechanisms after 2 test rounds consisting of eccentric exercise using pressure pain imaging of the wrist extensors. Pressure pain thresholds (PPTs) were assessed over 12 points forming a 3 × 4 matrix over the dominant elbow in 12 participants. From the PPT assessments, pressure pain maps were computed. Delayed onset muscle soreness was induced in an initial test round of high-intensity eccentric exercise. The second test round performed 7 days later aimed at resulting in adaptation. The PPTs were assessed before, immediately after, and 24 hours after the 2 test rounds of eccentric exercise. For the first test round, the mean PPT was significantly lower 24 hours after exercise compared with before exercise (389.5 ± 64.1 vs. 500.5 ± 66.4 kPa, respectively; p = 0.02). For the second test round, the PPT was similar before and 24 hours after (447.7 ± 51.3 vs. 458.0 ± 73.1 kPa, respectively; p = 1.0). This study demonstrated adaptive effects of the wrist extensors monitored by pain imaging technique in healthy untrained humans. A lack of hyperalgesia, i.e., no decrease in PPT underlined adaptation after the second test round of eccentric exercise performed 7 days after the initial test round. The present findings showed for the first time that repeated eccentric exercise performed twice over 2 weeks protects the wrist extensor muscles from developing exacerbated pressure pain sensitivity. Thus, the addition of eccentric components to training regimens should be considered to induce protective adaptation.

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

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    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

  4. Differential Effects of Unilateral Concentric Vs. Eccentric Exercise on the Dominant and Nondominant Forearm Flexors.

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    Beck, Travis W; Ye, Xin; Wages, Nathan P

    2016-03-01

    The purpose of this study was to compare the electromyographic (EMG) intensity patterns after unilateral concentric vs. eccentric exercise in the dominant (DOM) and nondominant (NONDOM) forearm flexors. Twenty-six men (mean ± SD: age, 24.0 ± 3.7 years) volunteered to perform a maximal isometric muscle action of the DOM and NONDOM forearm flexors before (PRE) and immediately after (POST) a series of maximal concentric isokinetic or maximal eccentric isokinetic muscle actions of the DOM forearm flexors. The concentric isokinetic and eccentric isokinetic muscle actions were performed on separate days that were randomly ordered. However, in both cases, the subjects performed 6 sets of 10 maximal muscle actions. A bipolar surface EMG signal was detected from the biceps brachii of the DOM and NONDOM limbs during the PRE and POST isometric muscle actions. The signals were then analyzed with a wavelet analysis, and the resulting intensity patterns were classified with a paired pattern classification procedure. The results indicated that the EMG intensity patterns could be correctly classified into their respective PRE vs. POST categories with an accuracy rate that was significantly better than random (20 of 26 patterns = 76.9% accuracy) but only for the DOM limb following the eccentric muscle actions. All other classifications were not significantly better than random. These findings indicated that eccentric exercise had a significant influence on the muscle activation pattern for the forearm flexors. It is possible that the muscle damage resulting from eccentric exercise affects muscle spindle or golgi tendon organ or both activity, thereby altering the muscle activation pattern.

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

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    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.

  6. Effects of eccentric exercise in rehabilitation of phasic and tonic muscles after leg immobilization in rats.

    Science.gov (United States)

    Cornachione, Anabelle S; Cação-Benedini, Letícia O; Chesca, Deise Lucia; Martinez, Edson Z; Mattiello-Sverzut, Ana Claudia

    2014-10-01

    Eccentric exercise is an essential resource for skeletal muscle rehabilitation following muscle disuse however, abnormalities linked to the tissue recuperation require further research. Our aim was analyze the adaptation ability of rehabilitated muscular tissue in rats during different periods of eccentric training after 10 days of limb immobilization. Twenty-seven Wistar rats were divided into six groups: immobilized 10 days, immobilized and eccentric trained for 10 days, immobilized and eccentric trained for 21 days, and three age-matched control groups. After sacrifice, soleus and plantaris muscles were frozen, cut and stained for general histology using hematoxylin and eosin and Gomori trichrome methods and immunohistochemical methods for fiber typing (mATPase, NADH2-TR), for capillaries (CD31) and intermediate filaments (desmin, vimentin) and high resolution microscopy of resin embedded material. Immobilization resulted in more intense morphological alterations in soleus muscles such as formation of target fibers, nuclear centralization, a reduction in the number of type I fibers, diameter of type I, IIA, IIAD fibers, and capillaries. After 10 days of eccentric training, increases in the nuclear centralization and the number of lobulated fibers were observed. This period was insufficient to reestablish the capillary/fiber (C/F) ratio and distribution of fiber types as that observed in the control group. However, 21 days of rehabilitation allowed the reversal of all morphological and quantitative abnormalities. For the plantaris muscles, 10-days of training restored their basic characteristics. Despite the fact that immobilization affected soleus and plantaris muscles, 10 days of eccentric training was insufficient to restore the morphological characteristics of soleus muscles, which was not the case observed in plantaris muscle.

  7. 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

  8. The antisaccade task: Vector inversion contributes to a statistical summary representation of target eccentricities.

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    Heath, Matthew; Gillen, Caitlin; Weiler, Jeffrey

    2015-01-01

    Antisaccades require the top-down suppression of a stimulus-driven prosaccade (i.e., response suppression) and the inversion of a target's spatial location to mirror-symmetrical space (i.e., vector inversion). Moreover, recent work has shown that antisaccade amplitudes are characterized by a statistical summary representation (SSR) of the target eccentricities included in a stimulus-set--a result suggesting that antisaccades are supported via the same relative visual information as perceptions. The present investigation sought to determine whether response suppression and the disruption of real-time control or vector inversion contribute to a SSR in oculomotor control. Participants completed pro- and antisaccades (target eccentricities of 10.5°, 15.5°, and 20.5°) in blocks of trials that differed with regard to the frequency that individual target eccentricities were presented. The manipulation of target eccentricity frequency was used to determine whether the most frequently presented target within a stimulus-set (i.e., the SSR) influences saccade amplitudes. Moreover, we disrupted the real-time control of prosaccades by requiring participants to suppress their response for a brief visual delay (i.e., 2000 ms: so-called delay prosaccade). As expected, antisaccades and delay prosaccades produced equivalent reaction times. In turn, amplitudes for delay prosaccades were refractory to the manipulation of target eccentricity frequency, whereas antisaccades were biased in the direction of the most frequently presented target within a stimulus-set. Accordingly, we propose that vector inversion contributes to the mediation of target eccentricities via a SSR and that such a phenomenon provides convergent evidence that a relative visual percept mediates antisaccades.

  9. Influence of background size, luminance and eccentricity on different adaptation mechanisms.

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    Gloriani, Alejandro H; Matesanz, Beatriz M; Barrionuevo, Pablo A; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A

    2016-08-01

    Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06-110cd/m(2)) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5cd/m(2). In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range.

  10. 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.

  11. The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b

    Science.gov (United States)

    Winn, Joshua N.; Howard, Andrew W.; Johnson, John A.; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colon, Knicole D.; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F.; Kadakia, Shimonee; Vanderbei, Robert J.; Adams, Elisabeth R.; Lockhart, Matthew; Crossfield, Ian J.; Valenti, Jeff A.; Dantowitz, Ronald; Carter, Joshua A.

    2009-01-01

    We reported the first detection of the transit ingress, revealing the transit duration to be 11.64 plus or minus 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibited an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. Thus, the orbit of this planet is not only highly eccentric but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism.

  12. Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

    Science.gov (United States)

    Croisier, J L; Camus, G; Deby-Dupont, G; Bertrand, F; Lhermerout, C; Crielaard, J M; Juchmès-Ferir, A; Deby, C; Albert, A; Lamy, M

    1996-01-01

    To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle

  13. Cardiovascular Response and Serum Interleukin-6 Level in Concentric Vs. Eccentric Exercise.

    Science.gov (United States)

    Agarwal, Mayank; Singh, Shraddha; Narayan, Jagdish; Pandey, Shivani; Tiwari, Sunita; Sharma, Priyanka

    2017-04-01

    Cardiovascular Disease (CVD) is a leading cause of morbidity and mortality in India. Resistance exercise is strongly recommended for implementation in CVD prevention programs. Dynamic resistance exercise comprises of concentric (muscle shortening) and eccentric (muscle lengthening) phase. The contraction of skeletal muscle promotes the synthesis and secretion of cytokines and peptides from myocytes, known as 'myokines'. Interleukin-6 (IL-6) is the first myokine to be released in the blood in response to exercise. To compare the cardiovascular response and serum IL-6 level in concentric and eccentric exercise done at same absolute workload. In this non-randomised crossover study 24, apparently healthy and young male adults performed an acute bout of concentric and eccentric exercise. Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Heart Rate (HR), Mean Arterial Pressure (MAP), Pulse Pressure (PP) and serum IL-6 were measured just before and immediately after exercise. Paired t-test or Wilcoxon signed-rank test were applied to compare the data within-group and in-between group. SBP, HR, MAP, PP, DBP and IL-6 level increased significantly after both, concentric and eccentric exercise. The mean change in SBP, HR, MAP, PP, and IL-6 after concentric exercise (18.54±3.06, 57.21±10.73, 8.35±1.40, 15.25±5.29, 5.40±3.13 respectively) was significantly higher than after eccentric exercise (13.38±1.72, 43.25±8.34, 6.50±1.0, 10.21±3.16, 4.36±2.54 respectively). A non-significant rise in DBP was obtained after concentric exercise (3.25±2.79) as compared to eccentric exercise (3.08±1.89). Eccentric exercise not only caused a lesser cardiovascular demand as compared to concentric exercise but also a significant increment in IL-6 level. Exercise-induced IL-6 may prevent the initiation and development of CVD. Hence, eccentric exercise training might be recommended for reducing morbidity and mortality in individuals with- or at a risk of developing CVD.

  14. 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

    . 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...

  15. 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

    Lower-bound calculations based on the finite element method are used to determine the bearing capacity of a strip foundation subjected to a vertical, eccentric load on cohesionless soil with varying surcharges. The soil is assumed perfectly plastic following the Mohr-Coulomb failure criterion....... 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...

  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

    BACKGROUND: The aim of this laboratory study was to investigate the effects of eccentric exercises on the trapezius muscle spatial electromyographic (EMG) activity during computer work with active and passive pauses. METHODS: Twelve healthy male subjects performed computer work with passive (relax......) 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 (Pactive pauses compared with passive ones (P

  17. Eccentricity generation in hierarchical triple systems with coplanar and initially circular orbits

    CERN Document Server

    Georgakarakos, Nikolaos

    2014-01-01

    We develop a technique for estimating the inner eccentricity in hierarchical triple systems with well separated components. We investigate systems with initially circular and coplanar orbits and comparable masses. The technique is based on an expansion of the rate of change of the Runge-Lenz vector for calculating short period terms by using first order perturbation theory. The combination of the short period terms with terms arising from octupole level secular theory, results in the derivation of a rather simple formula for the eccentricity of the inner binary. The theoretical results are tested against numerical integrations of the full equations of motion. Comparison is also made with other results on the subject.

  18. Effect of eccentric exercise-induced muscle damage on electromyographyic activity of quadriceps in untrained healthy females.

    Science.gov (United States)

    Rezaei, Mandana; Ebrahimi-Takamjani, Ismael; Jamshidi, Ali A; Vassaghi-Gharamaleki, Behnoush; Hedayatpour, Nosratollah; Havaei, Naser

    2014-01-01

    The aim of this study was to investigate muscle damage indicators and electromyography activities of quadriceps muscles at 25° of hip flexion in untrained healthy females after an eccentric exercise induced muscle fiber damage. A total of 14 healthy females participated in this pre-experimental study. The subjects performed maximal eccentric quadriceps contractions at 25˚ of hip flexion. Maximum voluntary extensor isometric and concentric moments, angle of maximum moment for concentric contractions, perceived pain intensity, and pain pressure threshold were examined before, immediately, 48 hours, 120 hours and 14 days after eccentric exercise. Additionally, electromyography of three parts of quadriceps muscle, knee flexion range of motion and thigh circumference were measured before and after eccentric exercise. Significant reductions in maximum isometric moment and maximum concentric moment were observed at angular velocity of 60˚ per sec immediately after eccentric exercise (peccentric exercise. Increased pain intensity and decreased knee joint range of motion manifested 48 hours after eccentric exercise. Pain pressure threshold for the quadriceps was higher 14 days after exercise as compared to 48 and 120 hours (p0.05). Eccentric exercise performed at 25˚ of hip flexion resulted in muscle fiber injuries within the quadriceps muscle. However, electromyography of quadriceps muscle was not significantly different than the baseline. The result indicates that hip joint position may modify the effect of eccentric exercise on muscle activation.

  19. The impact of altered task mechanics on timing and duration of eccentric bi-articular muscle contractions during cycling.

    Science.gov (United States)

    Connick, Mark J; Li, François-Xavier

    2013-02-01

    In order to understand muscle adaptations to altered task mechanics during cycling, this study investigated the impact of altered seat height and cadence on timing and duration of gastrocnemius (GAST), biceps femoris (BF) and vastus lateralis (VL) eccentric contractions and muscle activation patterns, and cycling economy. Ten male cyclists completed 9 × 5 min of cycling at 3 seat heights and 3 cadences. Three-dimensional leg kinematics and muscle activation patterns were recorded to estimate timing of eccentric muscle contractions. Onset, offset and duration of eccentric contractions and, onset, offset and duration of muscle activation were calculated, along with cycling economy. Duration of GAST and VL eccentric contractions decreased with increasing seat height due to earlier offset of eccentric muscle contractions. Duration of BF eccentric contractions significantly increased with seat height due to a later eccentric contraction offset. Offset of GAST and BF muscle activation occurred earlier with increasing cadence. Cycling economy was significantly affected by cadence but not seat height. The results suggest that as a consequence of altered seat height, proprioceptive feedback is used to fine-tune the timing of bi-articular eccentric muscle contractions. These results may have implications for seat height self-selection.

  20. Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy : A Double-Blinded Randomized Study

    NARCIS (Netherlands)

    Thijs, Karin M; Zwerver, Johannes; Backx, Frank J G; Steeneken, Victor; Rayer, Stephan; Groenenboom, Petra; Moen, Maarten H

    2016-01-01

    OBJECTIVE: To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks. DESIGN: Randomized controlled trial. SETTI

  1. 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.

  2. 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....

  3. Greater Strength Gains after Training with Accentuated Eccentric than Traditional Isoinertial Loads in Already Strength-Trained Men.

    Science.gov (United States)

    Walker, Simon; Blazevich, Anthony J; Haff, G Gregory; Tufano, James J; Newton, Robert U; Häkkinen, Keijo

    2016-01-01

    As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s(-1)) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p eccentric load (10 ± 9%, p eccentric load group was significantly greater (p eccentric load group only (28%, p eccentric load training led

  4. Greater strength gains after training with accentuated eccentric than traditional isoinertial loading loads in already strength-trained men

    Directory of Open Access Journals (Sweden)

    Simon eWalker

    2016-04-01

    Full Text Available As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength-trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading versus traditional isoinertial resistance training in strength-trained men. Young (22±3 y, 177±6 cm, 76±10 kg, n = 28 strength-trained men (2.6±2.2 y experience were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40% or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1 and three sets of 10-RM (session 2 bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle and isokinetic (concentric and eccentric 30°.s-1 knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasound and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18±10% vs. 1±5%, p<0.01, which was accompanied by an increase in voluntary activation (3.5±5%, p<0.05. Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10±9%, p<0.05, whereas concentric torque increased equally in both

  5. Numerical studies of an eccentric tube-in-tube helically coiled heat exchanger for IHEP-ADS helium purification system

    CERN Document Server

    Zhang, Jianqin

    2014-01-01

    The tube-in-tube helically coiled (TTHC) heat exchanger is preferred in the purifier of IHEP-ADS helium purification system. The position of an internal tube is usually eccentric in a TTHC heat exchanger in practice, while most TTHC heat exchangers in the literature studied are concentric. In this paper, TTHC heat exchangers with different eccentricity ratios are numerically studied for turbulent flow and heat transfer characteristics under different flow rates. The fluid considered is helium at the pressure of 20Mpa, with temperature dependent thermo-physical properties for the inner tube and the annulus. The inner Nusselt number between the concentric and eccentric TTHC heat exchangers are compared, so is the annulus Nusselt number. The results show that with the eccentricity increasing, the annulus Nusselt number increases substantially. According to the numerical data, new empirical correlations of Nusselt number as a function of Reynolds number and eccentricity for the inner tube and the annulus are pres...

  6. The Photoeccentric Effect and Proto Hot Jupiters II. KOI-1474.01, an eccentric planet perturbed by an unseen companion

    CERN Document Server

    Dawson, Rebekah I; Morton, Timothy D; Crepp, Justin R; Fabrycky, Daniel C; Murray-Clay, Ruth A; Howard, Andrew W

    2012-01-01

    The exoplanets known as hot Jupiters---Jupiter-sized planets with periods less than 10 days---likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. (2012) 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 +0.10/-0.07, skirting the proto hot Jupiter boundary. Combining Keplerphotometry, ground-based spectroscopy, and stellar evolutio...

  7. Fluctuation induced symmetry breaking and the equality of multi-particle eccentricities for four or more particles

    CERN Document Server

    Bzdak, Adam; McLerran, Larry

    2013-01-01

    We discuss eccentricities (ellipticity and triangularity) generated in nucleus-nucleus and proton-nucleus collisions. We define multi-particle eccentricities $\\epsilon_n\\{m\\}$ which are associated with the $n'th$ angular multipole moment for $m$ particles. We show that in the limit of fluctuation dominance all of the $\\epsilon_n\\{m\\}$'s are approximately equal for $m \\ge 4$. For dynamics linearly responding to these eccentricities such as hydrodynamics or proposed in this paper weakly interacting field theory, these relations among eccentricities are translated into relations among flow moments $v_n\\{m\\}$. We argue that these eccentricities are generated by a two dimension Gaussian integral distribution whose width controls the magnitude of fluctuations and whose center gives $\\epsilon_n\\{m\\}$ for $m \\ge 4$. This center value breaks the rotational symmetry for an underlying random distribution.

  8. Combination of eccentric exercise and neuromuscular electrical stimulation to improve biomechanical limb symmetry after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Lepley, Lindsey K; Wojtys, Edward M; Palmieri-Smith, Riann M

    2015-08-01

    We have previously reported that an eccentrically-based rehabilitation protocol post-ACLr induced greater quadriceps activation and strength than a neuromuscular electrical stimulation (NMES) intervention and was just as effective as a combined NMES and eccentric intervention. However, the effect an eccentrically-based intervention has on restoring normal knee mechanics during a single-legged landing task remains unknown. Thirty-six individuals post-injury were placed into four treatment groups: NMES and eccentrics, eccentrics-only, NMES-only, standard of care, and healthy controls participated. NMES and eccentrics received a combined NMES and eccentric protocol post-reconstruction (each treatment 2× per week for 6 weeks), whereas groups NMES-only and eccentric-only received only the NMES or eccentric therapy, respectively. To evaluate knee mechanics limb symmetry, the area under the curve for knee flexion angle and extension moment was derived and then normalized to the contralateral limb. Quadriceps strength was evaluated using the quadriceps index. Compared to healthy, reduced sagittal plane knee limb symmetry was found for groups NMES-only, ECC-only and standard of care for knee extension moment (Peccentrics (P>0.06). No difference between groups was detected for knee flexion angle limb symmetry (P>0.05). Greater knee flexion angles and moments over stance were related to quadriceps strength. The NMES and eccentrics group was found to restore biomechanical limb symmetry that was most closely related to healthy individuals following ACL reconstruction. Greater knee flexion angles and moments over stance were related to quadriceps strength. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Effects of eccentric exercise on toll-like receptor 4 signaling pathway in peripheral blood mononuclear cells.

    Science.gov (United States)

    Fernandez-Gonzalo, Rodrigo; De Paz, José A; Rodriguez-Miguelez, Paula; Cuevas, María J; González-Gallego, Javier

    2012-06-01

    This study aimed to investigate the response of the toll-like receptor 4 (TLR4) signaling pathway to an acute bout of eccentric exercise, and to assess whether eccentric training attenuated the effects induced by acute eccentric exercise. Twenty men (22.4 ± 0.5 yr) were divided into a control group (CG, n = 8) and a training group (TG, n = 12). Both groups performed two acute eccentric bouts on a squat machine in a 9-wk interval. During this time, TG followed a 6-wk eccentric training program (3 session/wk; 3-5 sets of 10 repetitions with loads ranging between the 40 and 50% of maximal isometric voluntary contraction). CD14, TLR4, and TNF-α mRNA levels, and CD14, TLR4, myeloid differentiation factor 88, tumor necrosis factor receptor-associated factor 6, TIR-domain-containing adapter-inducing interferon-β, phospho-IκB kinases, phospho-IκB, phospho-ERK-1/2, and TNF-α protein concentration were measured in peripheral blood mononuclear cells, before, immediately, and 2 h after each eccentric bout. The first acute eccentric bout triggered a proinflammatory response mediated by an upregulation of all of the factors measured within the TLR4 signaling pathway. Following the training period and after the second acute bout, CG showed a similar proinflammatory response than that seen after the first bout. However, the eccentric training intervention decreased significantly the protein concentration of all factors analyzed in TG compared with results obtained after the first bout. These results suggest that the TLR4-signaling pathway plays a critical role in the proinflammatory response seen after acute eccentric exercise. This response was attenuated after an eccentric training program through myeloid differentiation factor 88-dependent and -independent pathways.

  10. Frequency modulation reveals the phasing of orbital eccentricity during Cretaceous Oceanic Anoxic Event II and the Eocene hyperthermals

    Science.gov (United States)

    Laurin, Jiří; Meyers, Stephen R.; Galeotti, Simone; Lanci, Luca

    2016-05-01

    Major advances in our understanding of paleoclimate change derive from a precise reconstruction of the periods, amplitudes and phases of the 'Milankovitch cycles' of precession, obliquity and eccentricity. While numerous quantitative approaches exist for the identification of these astronomical cycles in stratigraphic data, limitations in radioisotopic dating, and instability of the theoretical astronomical solutions beyond ∼50 Myr ago, can challenge identification of the phase relationships needed to constrain climate response and anchor floating astrochronologies. Here we demonstrate that interference patterns accompanying frequency modulation (FM) of short eccentricity provide a robust basis for identifying the phase of long eccentricity forcing in stratigraphic data. One- and two-dimensional models of sedimentary distortion of the astronomical signal are used to evaluate the veracity of the FM method, and indicate that pristine eccentricity FM can be readily distinguished in paleo-records. Apart from paleoclimatic implications, the FM approach provides a quantitative technique for testing and calibrating theoretical astronomical solutions, and for refining chronologies for the deep past. We present two case studies that use the FM approach to evaluate major carbon-cycle perturbations of the Eocene and Late Cretaceous. Interference patterns in the short-eccentricity band reveal that Eocene hyperthermals ETM2 ('Elmo'), H2, I1 and ETM3 (X; ∼52-54 Myr ago) were associated with maxima in the 405-kyr cycle of orbital eccentricity. The same eccentricity configuration favored regional anoxic episodes in the Mediterranean during the Middle and Late Cenomanian (∼94.5-97 Myr ago). The initial phase of the global Oceanic Anoxic Event II (OAE II; ∼93.9-94.5 Myr ago) coincides with maximum and falling 405-kyr eccentricity, and the recovery phase occurs during minimum and rising 405-kyr eccentricity. On a Myr scale, the event overlaps with a node in eccentricity

  11. 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.

  12. 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.

  13. Muscle fascicle behavior during eccentric cycling and its relation to muscle soreness.

    Science.gov (United States)

    Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

    2015-04-01

    A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect. Eleven untrained men (27.1 ± 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 ± 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling. Soreness was greater (P knee angles were evident between bouts. However, fascicle elongation was 16% less during ECC2 than ECC1 (P knee joint angle during ECC2 than ECC1 (P = 0.055). These results suggest that a lesser fascicle elongation and earlier TT elongation were associated with reduced muscle soreness after ECC2 than ECC1; thus, changes in muscle-tendon behavior may be an important mechanism underpinning the protective effect.

  14. The effect of eccentric exercise on position sense and joint reaction angle of the lower limbs.

    Science.gov (United States)

    Paschalis, V; Nikolaidis, M G; Giakas, G; Jamurtas, A Z; Pappas, A; Koutedakis, Y

    2007-04-01

    Impaired position sense and impaired joint reaction angle of the lower limbs after muscle-damaging activities is a serious functional limitation that may lead to an increased risk of injury, particularly in older populations. The purpose of the present study was to examine whether position sense and joint reaction angle to release can be affected by eccentric exercise-induced muscle damage. Twelve women underwent an isokinetic exercise session of the lower limb. Isometric peak torque, delayed-onset muscle soreness, serum creatine kinase, position sense, and knee joint reaction angle to release were examined before, immediately after, and 24, 48, and 72 h post-exercise. Due to the effect of eccentric exercise, subjects persistently placed their lower limb at a more extended position, representing a shorter knee extensor muscle. Eccentric exercise increased the knee reaction angle of the lower limb after release from 0 degrees and 15 degrees but not from 30 degrees and 45 degrees . Position sense and joint reaction to release were similarly affected by eccentric exercise and independently of visual feedback. Position sense was impaired only immediately post-exercise (probably due to muscle fatigue), whereas impairment of the reaction angle to release persisted up to 3 days post-exercise (probably due to muscle damage). Attenuation of position sense and joint reaction angle of the lower limbs after damaging activities is a serious functional limitation that may lead to an increase risk of injury, particularly in older populations.

  15. 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.

  16. 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…

  17. Diagnosis of airgap eccentricity fault in the inverter driven induction motor drives by transformative techniques

    Directory of Open Access Journals (Sweden)

    Khadim Moin Siddiqui

    2016-09-01

    Full Text Available In the present paper, the airgap eccentricity fault of the induction motor has been diagnosed by digital signal processing transformative techniques in the inverter driven induction motor drives. The airgap eccentricity fault has been diagnosed in the transient condition by time domain as well as time-frequency domain techniques with the help of a proposed dynamic simulation model. In the past, many signal processing techniques had been used for various induction motor fault detection purpose such as fast Fourier transform, Hilbert transform, short term Fourier transform, etc. But, all techniques faced some sort of disadvantages. Therefore, in this paper, all shortcomings of the previous used signal processing techniques have been solved by newly wavelet transform's approximation signal. The low frequency approximation signal has been used to diagnose the eccentricity fault in the transient condition. Therefore, early fault diagnosis of the motor is possible and averted the motor before reaching in the ruinous conditions. As a result, the industries may save large revenues and unexpected failure conditions. The obtained results clearly demonstrate that the developed diagnostic technique may reliably separate airgap eccentricity fault in many stages.

  18. Dynamic properties and time response of frameworks with semi-rigid and eccentric connections

    Directory of Open Access Journals (Sweden)

    Gopčević Špiro

    2011-01-01

    Full Text Available The paper is considering effects of the semi-rigid and eccentric joint connections of framework structures upon its dynamic properties and the time response due to an earthquake action. The corresponding numerical method representing the linear structural behavior is developed. Semi-rigid connections at beam ends are presented by the rotational springs at beam's ends, with linear moment-rotation relationship. Eccentricity of joint connections is presented by the corresponding short infinitely rigid links at beam's ends. The effect of semi-rigid and eccentric connections is introduced in the numerical model by the corresponding corrective matrix. The corrective matrix is applied upon the conventional stiffness matrix of the beam element with usual rigid and centric connections. As important dynamic properties, the change of the natural circular frequencies and the natural modes, due to variation of joint rigidity and eccentricity of beam-to-column connections, is analyzed. In the time response structural analysis, considering displacements only, dynamic loading due to an earthquake defined by a given accelerogram is considered. The solution of the differential equations of motion is obtained by direct numerical step-by-step integration using the α method (Hilber-Hughes- Taylor. In order to perform the numerical analysis, all considered numerical models and methods are implemented into the corresponding computer code, called ELAN, which is then used for the parametric analyses presented in the paper.

  19. Experimental study and CFD simulation of rotational eccentric cylinder in a magnetorheological fluid

    Energy Technology Data Exchange (ETDEWEB)

    Omidbeygi, F. [Computational Fluid Dynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, 16846 Tehran (Iran, Islamic Republic of); Hashemabadi, S.H., E-mail: hashemabadi@iust.ac.ir [Computational Fluid Dynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, 16846 Tehran (Iran, Islamic Republic of)

    2012-07-15

    In this study, a magnetorheological (MR) fluid is prepared using carbonyl iron filings and low viscosity lubricating oil. The effects of magnetic field and weight percentage of particles on the viscosity of the MR fluid have been measured using a rotational viscometer. The yield stress under an applied magnetic field was also obtained experimentally. In the absence of an applied magnetic field, the MR fluid behaves as a Newtonian fluid. When the magnetic field is applied, the MR fluid behaves like Bingham plastics with a magnetic field dependent yield stress. Afterward, the results compared with those of CFD simulation of two eccentric cylinders in the MR fluid. Results show that the influences of MR effects, caused by the applied magnetic field, on the model characteristics are significant and not negligible. The viscosity is enhanced by increasing of the magnetic field, eccentricity ratio and weight percentage of suspensions. The MR effects and increasing of weight percentage and eccentricity ratio also provide an enhancement in the yield stresses and required total torque for rotation of inner cylinder. Also the simulation results indicate a good representation of the experiment by the model. - Highlights: Black-Right-Pointing-Pointer Preparation of a magnetorheological fluid with carbonyl iron particles in lubricating oil. Black-Right-Pointing-Pointer Rheological measurement for influence of solid content and magnetic field intensity. Black-Right-Pointing-Pointer Simulation of eccentric rotating cylinder in prepared MR fluid with CFD techniques.

  20. 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 tw

  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. 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.

  3. Muscular hypertrophy and changes in cytokine production after eccentric training in the rat skeletal muscle.

    Science.gov (United States)

    Ochi, Eisuke; Nakazato, Koichi; Ishii, Naokata

    2011-08-01

    We investigated the time course effects of eccentric training on muscular size, strength, and growth factor/cytokine production by using an isokinetic-exercise system for rats. Male Wistar rats (n = 34) were randomly assigned into 4 groups: 5 session eccentric-training group (ECC5S, n = 10); 5 session sham-operated group (CON5S, n = 10); 10 session eccentric-training group (ECC10S, n = 7); 10 session sham-operated group (CON10S, n = 7). In each group, a session of either training or sham operation was performed every 2 days. The training consisted of 4 sets of forced dorsiflexion (5 repetitions) combined with electric stimulation of plantar flexors. The wet weight of medial gastrocnemius muscle did not increase significantly after 5 sessions of training, whereas that after 10 sessions of training significantly increased with a concomitant increase in the cross-sectional area (CSA) of muscle fibers (weight, p eccentric training for 20 days cause increases in muscular size and strength associated with increases in IL-6, follistatin, phospho-stat-3, and a decrease in myostatin. The delayed responses of IL-6, myostatin, phospho-stat-3, and follistatin would be due to the chronic effects of repeated training and possibly important for muscular hypertrophy.

  4. The influence of eccentric exercise on mRNA expression of skeletal muscle regulators.

    Science.gov (United States)

    Jensky, Nicole E; Sims, Jennifer K; Rice, Judd C; Dreyer, Hans C; Schroeder, E Todd

    2007-11-01

    To evaluate change in myostatin, follistatin, MyoD and SGT mRNA gene expression using eccentric exercise to study mechanisms of skeletal muscle hypertrophy. Young (28+/-5 years) and older (68+/-6 years) men participated in a bout of maximal single-leg eccentric knee extension on an isokinetic dynamometer at 60 degrees /s: six sets, 12-16 maximal eccentric repetitions. Muscle biopsies of the vastus lateralis were obtained from the dominant leg before exercise and 24 h after exercise. Paired t tests were used to compare change (pre versus post-exercise) for normalized gene expression in all variables. Independent t tests were performed to test group differences (young vs. older). A probability level of Peccentric exercise. Similarly, we did not observe significant change in myostatin (-3.83+/-8.8; P=0.23), follistatin (-2.66+/-5.2; P=0.17), MyoD (-0.13+/-3.1; P=0.90), or SGT (-1.6+/-3.5; P=0.19) mRNA expression in older subjects. Furthermore, the non-significant changes in mRNA expression were not different between young and older subjects, P>0.23 for all variables. Our data suggests that a single bout of maximal eccentric exercise does not alter myostatin, follistatin, MyoD or SGT mRNA gene expression in young or older subjects.

  5. Flywheel resistance training calls for greater eccentric muscle activation than weight training.

    Science.gov (United States)

    Norrbrand, Lena; Pozzo, Marco; Tesch, Per A

    2010-11-01

    Changes in muscle activation and performance were studied in healthy men in response to 5 weeks of resistance training with or without "eccentric overload". Subjects, assigned to either weight stack (grp WS; n = 8) or iso-inertial "eccentric overload" flywheel (grp FW; n = 9) knee extensor resistance training, completed 12 sessions of four sets of seven concentric-eccentric actions. Pre- and post-measurements comprised maximal voluntary contraction (MVC), rate of force development (RFD) and training mode-specific force. Root mean square electromyographic (EMG(RMS)) activity of mm. vastus lateralis and medialis was assessed during MVC and used to normalize EMG(RMS) for training mode-specific concentric (EMG(CON)) and eccentric (EMG(ECC)) actions at 90°, 120° and 150° knee joint angles. Grp FW showed greater (p  0.05), MVC and training-specific strength increased (p exercise compared to standard weight lifting could be attributed to its unique iso-inertial loading features. Hence, the resulting greater mechanical stress may explain the robust muscle hypertrophy reported earlier in response to flywheel resistance training.

  6. Chronic eccentric cycling improves quadriceps muscle structure and maximum cycling power.

    Science.gov (United States)

    Leong, C H; McDermott, W J; Elmer, S J; Martin, J C

    2014-06-01

    An interesting finding from eccentric exercise training interventions is the presence of muscle hypertrophy without changes in maximum concentric strength and/or power. The lack of improvements in concentric strength and/or power could be due to long lasting suppressive effects on muscle force production following eccentric training. Thus, improvements in concentric strength and/or power might not be detected until muscle tissue has recovered (e. g., several weeks post-training). We evaluated alterations in muscular structure (rectus-femoris, RF, and vastus lateralis, VL, thickness and pennation angles) and maximum concentric cycling power (Pmax) 1-week following 8-weeks of eccentric cycling training (2×/week; 5-10.5 min; 20-55% of Pmax). Pmax was assessed again at 8-weeks post-training. At 1 week post-training, RF and VL thickness increased by 24±4% and 13±2%, respectively, and RF and VL pennation angles increased by 31±4% and 13±1%, respectively (all Peccentric cycling can be a time-effective intervention for improving muscular structure and function in the lower body of healthy individuals. The larger Pmax increase detected at 8-weeks post-training implies that sufficient recovery might be necessary to fully detect changes in muscular power after eccentric cycling training.

  7. 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...... returning to sports following injury....

  8. Zoom & Whirl Eccentric equatorial orbits around spinning black holes and their evolution under gravitational radiation reaction

    CERN Document Server

    Glampedakis, K; Glampedakis, Kostas; Kennefick, Daniel

    2002-01-01

    We study eccentric equatorial orbits of a test-body around a Kerr black hole under the influence of gravitational radiation reaction. We have adopted a well established two-step approach: assuming that the particle is moving along a geodesic (justifiable as long as the orbital evolution is adiabatic) we calculate numerically the fluxes of energy and angular momentum radiated to infinity and to the black hole horizon, via the Teukolsky-Sasaki-Nakamura formalism. We can then infer the rate of change of orbital energy and angular momentum and thus the evolution of the orbit. The orbits are fully described by a semi-latus rectum $p$ and an eccentricity $e$. We find that while, during the inspiral, $e$ decreases until shortly before the orbit reaches the separatrix of stable bound orbits (which is defined by $p_{s}(e)$), in many astrophysically relevant cases the eccentricity will still be significant in the last stages of the inspiral. In addition, when a critical value $p_{crit}(e)$ is reached, the eccentricity ...

  9. 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.

  10. 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...

  11. Attenuation of indirect markers of eccentric exercise-induced muscle damage by curcumin.

    Science.gov (United States)

    Tanabe, Yoko; Maeda, Seiji; Akazawa, Nobuhiko; Zempo-Miyaki, Asako; Choi, Youngju; Ra, Song-Gyu; Imaizumi, Atsushi; Otsuka, Yoshihiko; Nosaka, Kazunori

    2015-09-01

    Polyphenolic curcumin is known to have potent anti-inflammatory effects; thus the present study investigated the hypothesis that curcumin ingestion would attenuate muscle damage after eccentric exercise. Fourteen untrained young men (24 ± 1 years) performed 50 maximal isokinetic (120°/s) eccentric contractions of the elbow flexors of one arm on an isokinetic dynamometer and the same exercise with the other arm 4 weeks later. They took 150 mg of curcumin (theracurmin) or placebo (starch) orally before and 12 h after each eccentric exercise bout in a randomised, crossover design. Maximal voluntary contraction (MVC) torque of the elbow flexors, range of motion of the elbow joint, upper-arm circumference, muscle soreness, serum creatine kinase (CK) activity, and plasma interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentration were measured before, immediately after, and 24, 48, 72 and 96 h after each eccentric exercise. Changes in these variables over time were compared between curcumin and placebo conditions by two-way repeated measures ANOVA. MVC torque decreased smaller and recovered faster (e.g., 4 days post-exercise: -31 ± 13 % vs. -15 ± 15 %), and peak serum CK activity was smaller (peak: 7684 ± 8959 IU/L vs. 3398 ± 3562 IU/L) for curcumin than placebo condition (P exercise. It is concluded that theracurmin ingestion attenuates some aspects of muscle damage such as MVC loss and CK activity increase.

  12. Acute postexercise effects of concentric and eccentric exercise on glucose tolerance.

    Science.gov (United States)

    Cook, Matthew David; Myers, Stephen David; Kelly, John Stephen Michael; Willems, Mark Elisabeth Theodorus

    2015-02-01

    Impaired glucose tolerance was shown to be present 48 hr following muscle-damaging eccentric exercise. We examined the acute effect of concentric and muscle-damaging eccentric exercise, matched for intensity, on the responses to a 2-hr 75-g oral glucose tolerance test (OGTT). Ten men (27 ± 9 years, 178 ± 7 cm, 75 ± 11 kg, VO₂max: 52.3 ± 7.3 ml · kg⁻¹ · min⁻¹) underwent three OGTTs after an overnight 12 hr fast: rest (control), 40-min (5 × 8-min with 2-min interbout rest) of concentric (level running, 0%, CON) or eccentric exercise (downhill running, -12%, ECC). Running intensity was matched at 60% of maximal metabolic equivalent. Maximal isometric force of m. quadriceps femoris of both legs was measured before and after the running protocols. Downhill running speed was higher (level: 9.7 ± 2.1, downhill: 13.8 ± 3.2 km · hr⁻¹, p eccentric exercise.

  13. 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.

  14. Reduced sarcoplasmic reticulum content of releasable Ca2+ in rat soleus muscle fibres after eccentric contractions

    DEFF Research Database (Denmark)

    Nielsen, J S; Sahlin, K; Ørtenblad, N

    2007-01-01

    AIM: The purpose was to evaluate the effects of fatiguing eccentric contractions (EC) on calcium (Ca2+) handling properties in mammalian type I muscles. We hypothesized that EC reduces both endogenous sarcoplasmic reticulum (SR) content of releasable Ca2+ (eSRCa2+) and myofibrillar Ca2+ sensitivity...

  15. Chronic Eccentric Exercise and Antioxidant Supplementation: Effects on Lipid Profile and Insulin Sensitivity.

    Science.gov (United States)

    Yfanti, Christina; Tsiokanos, Athanasios; Fatouros, Ioannis G; Theodorou, Anastasios A; Deli, Chariklia K; Koutedakis, Yiannis; Jamurtas, Athanasios Z

    2017-09-01

    Eccentric exercise has been shown to exert beneficial effects in both lipid profile and insulin sensitivity. Antioxidant supplementation during chronic exercise is controversial as it may prevent the physiological training-induced adaptations. The aim of this study was to investigate: 1) the minimum duration of the eccentric exercise training required before changes on metabolic parameters are observed and 2) whether antioxidant supplementation during training would interfere with these adaptations. Sixteen young healthy men were randomized into the Vit group (1 g of vitamin C and 400 IU vitamin E daily) and the placebo (PL) group. Subjects received the supplementation for 9 weeks. During weeks 5-9 all participants went through an eccentric exercise training protocol consisting of two exercise sessions (5 sets of 15 eccentric maximal voluntary contractions) per week. Plasma triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), apolipoproteins (Apo A1, Apo B and Lpa) and insulin sensitivity (HOMA) were assessed before the supplementation (week 0), at weeks 5, 6, 7, 8 and 9. TG, TC and LDL were significantly lower compared to pre supplementation at both weeks 8 and 9 (Peccentric exercise training is required before beneficial effects in lipid profile can be observed in healthy young men. Concomitant antioxidant supplementation does not interfere with the training-induced adaptations.

  16. 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

  17. Pain sensitivity is normalized after a repeated bout of eccentric exercise.

    Science.gov (United States)

    Hosseinzadeh, Mahdi; Andersen, Ole K; Arendt-Nielsen, Lars; Madeleine, Pascal

    2013-10-01

    The purpose of this study was to investigate the effect of repeated bouts of eccentric exercise on the nociceptive withdrawal reflex (NWR) threshold, a measure of sensitivity in the spinal nociceptive system. Sixteen healthy students (age 25.7 ± 0.6 years, BMI 24.8 ± 1 kg m(-2)) participated in this randomized, controlled, crossover study. Two identical bouts of high-intensity eccentric exercises were performed on the tibialis anterior muscle 7 days apart. Control sessions involving no exercise were performed 4 weeks apart the exercise sessions. Pressure pain thresholds (PPT) and the NWR threshold were recorded before, immediately after, and 1 day after both bouts of exercise. Pressure pain thresholds decreased significantly at two of the muscle belly sites on the day after initial bout compared with baseline. NWR threshold decreased by 25 ± 4 % immediately after initial bout and by 30 ± 5 % the next day (p eccentric exercise indicating that both localized and generalized pain sensitivity were normalized. In conclusion, this study for the first time documented that an initial bout of unaccustomed high-intensity eccentric exercise, which results in muscle soreness can induce central sensitization. A repeated bout of exercise, however, facilitates inherent protective spinal mechanisms against the development of muscle soreness.

  18. The ventriloquist in periphery: impact of eccentricity-related reliability on audio-visual localization.

    Science.gov (United States)

    Charbonneau, Geneviève; Véronneau, Marie; Boudrias-Fournier, Colin; Lepore, Franco; Collignon, Olivier

    2013-10-28

    The relative reliability of separate sensory estimates influences the way they are merged into a unified percept. We investigated how eccentricity-related changes in reliability of auditory and visual stimuli influence their integration across the entire frontal space. First, we surprisingly found that despite a strong decrease in auditory and visual unisensory localization abilities in periphery, the redundancy gain resulting from the congruent presentation of audio-visual targets was not affected by stimuli eccentricity. This result therefore contrasts with the common prediction that a reduction in sensory reliability necessarily induces an enhanced integrative gain. Second, we demonstrate that the visual capture of sounds observed with spatially incongruent audio-visual targets (ventriloquist effect) steadily decreases with eccentricity, paralleling a lowering of the relative reliability of unimodal visual over unimodal auditory stimuli in periphery. Moreover, at all eccentricities, the ventriloquist effect positively correlated with a weighted combination of the spatial resolution obtained in unisensory conditions. These findings support and extend the view that the localization of audio-visual stimuli relies on an optimal combination of auditory and visual information according to their respective spatial reliability. All together, these results evidence that the external spatial coordinates of multisensory events relative to an observer's body (e.g., eyes' or head's position) influence how this information is merged, and therefore determine the perceptual outcome.

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

    DEFF Research Database (Denmark)

    Thorborg, K; 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...

  20. 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 is decre......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...... is decreased in patients with external snapping hip compared with healthy matched controls, and to examine isometric hip abduction, adduction, extension, flexion, internal rotation, and external rotation in patients with external snapping hip and matched controls. Thirteen patients with external snapping hip....... 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...

  1. 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

  2. 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.

  3. Effectiveness of daily eccentric contractions induced via kilohertz frequency transcutaneous electrical stimulation on muscle atrophy.

    Science.gov (United States)

    Tanaka, Minoru; Nakanishi, Ryosuke; Murakami, Shinichiro; Fujita, Naoto; Kondo, Hiroyo; Ishihara, Akihiko; Roy, Roland R; Fujino, Hidemi

    2016-01-01

    The effects of daily repeated bouts of concentric, isometric, or eccentric contractions induced by high frequency (kilohertz) transcutaneous electrical stimulation in ameliorating atrophy of the soleus muscle in hindlimb unloaded rats were determined. Five groups of male rats were studied: control, hindlimb unloaded for 2 weeks (HU), or HU plus two daily bouts of concentric, isometric, or eccentric high-frequency electrical stimulation-induced contractions of the calf musculature. Soleus mass and fiber size were smaller, the levels of phosphorylated Akt1 and FoxO3a lower, and atrogin-1 and ubiquitinated proteins higher in the HU, and the HU plus concentric or isometric contraction groups than in the control group. In contrast, daily bouts of eccentric contractions maintained these values at near control levels and all measures were significantly different from all other HU groups. These results indicate that daily bouts of eccentric contractions induced by high-frequency stimulation inhibited the ubiquitin-proteasome catabolic pathway and enhanced the Akt1/FoxO3a anabolic pathway that resulted in a prevention of the atrophic response of the soleus muscle to chronic unloading.

  4. Effects of repeated concentric and eccentric contractions on tendon blood circulation.

    Science.gov (United States)

    Kubo, K

    2015-06-01

    Previous studies demonstrated that treatment involving eccentric training was effective in the conservative management of chronic tendinosis. However, the mechanisms for these phenomena are unknown. The purpose of this study was to compare changes in blood circulation of the tendons after the repeated concentric and eccentric contractions. 11 healthy males volunteered for this study. Subjects performed the repeated concentric (CON) and eccentric (ECC) contractions (5 sets of 10 maximal voluntary contractions) of the plantar flexors. During and after repeated contractions, oxyhemoglobin (Oxy), deoxyhemoglobin (Deoxy), total hemoglobin (THb), and oxygen saturation (StO2) of the Achilles tendons were measured using red laser lights. Oxy and THb increased during and after ECC, but not CON. Deoxy decreased during both CON and ECC. Increase in StO2 during and after ECC was greater than that during and after CON. These results suggested that changes in blood circulation of the Achilles tendon during and after repeated eccentric contractions were more remarkable than those during and after repeated concentric contractions.

  5. 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 (VO2), 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 VO2 (+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.

  6. Visual performance with changes in eccentricity in PROSE device: a case report.

    Science.gov (United States)

    Jagadeesh, Divya; Mahadevan, Rajeswari

    2014-01-01

    This case report describes the variations in visual performance of a subject with moderate keratoconus with changes in front surface eccentricities (FSEs) of PROSE (Prosthetic Replacement of Ocular Surface Ecosystem). PROSE device of 0.6 FSE provided maximum visual improvement and reduction in Higher Order Aberrations (HOAs) compared to 0, 0.3 and 0.8 FSEs in this clinical condition.

  7. The Bearing Capacity of Strip Footings in Cohesionless Soil Subject to Eccentric and Inclined Loads

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Damkilde, Lars; Krabbenhøft, Kristian

    2014-01-01

    Lower bound calculations based on the finite element method is used to determine the bearing capacity of a strip foundation subjected to an inclined, eccentric load on cohesionless soil with varying surcharges and with friction angles 25, 30 and 35°. The soil is assumed perfectly plastic followin...

  8. Eccentricity and fluting in young–growth western hemlock in Oregon.

    Science.gov (United States)

    Ryan Singleton; Dean S. DeBell; David D. Marshall; Barbara L. Gartner

    2004-01-01

    Stem irregularities can influence estimates of tree and stand attributes, efficiency of manufacturing processes, and quality of wood products. Eccentricity and fluting were characterized in young, managed western hemlock stands in the Oregon Coast Range. Sixty-one trees were selected from pure western hemlock stands across a range of age, site, and densities. The trees...

  9. Lower eccentric hamstring strength and single leg hop for distance predict hamstring injury in PETE students.

    Science.gov (United States)

    Goossens, L; Witvrouw, E; Vanden Bossche, L; De Clercq, D

    2015-01-01

    Hamstring injuries have not been under research in physical education teacher education (PETE) students so far. Within the frame of the development of an injury prevention program, for this study we conducted an analysis of modifiable risk factors for hamstring injuries in PETE students. Hamstring injuries of 102 freshmen bachelor PETE students were registered prospectively during one academic year. Eighty-one students completed maximum muscle strength tests of hip extensors, hamstrings, quadriceps (isometric) and hamstrings (eccentric) at the start of the academic year. Sixty-nine of the latter completed a single leg hop for distance (SLHD). Risk factors for hamstring injuries were statistically detected using logistic regression. Sixteen hamstring injuries (0.16 injuries/student/academic year; 0.46 injuries/1000 h) occurred to 10 participants. Eight cases were included in the risk factor analysis. Lower eccentric hamstring strength (odds ratio (ODD) = 0.977; p = 0.043), higher isometric/eccentric hamstring strength ratio (ODD = 970.500; p = 0.019) and lower score on the SLHD (ODD = 0.884; p = 0.005) were significant risk factors for hamstring injury. A combination of eccentric hamstring strength test and SLHD could give a good risk analysis of hamstring injuries in PETE students. This might offer great perspectives for easily applicable screening in a clinical setting.

  10. 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.

  11. Equipotential Surfaces and Lagrangian points in Non-synchronous, Eccentric Binary and Planetary Systems

    CERN Document Server

    Sepinsky, J F; Kalogera, V

    2006-01-01

    We investigate the existence and properties of equipotential surfaces and Lagrangian points in non-synchronous, eccentric binary star and planetary systems under the assumption of quasi-static equilibrium. We adopt a binary potential that accounts for non-synchronous rotation and eccentric orbits, and calculate the positions of the Lagrangian points as functions of the mass ratio, the degree of asynchronism, the orbital eccentricity, and the position of the stars or planets in their relative orbit. We find that the geometry of the equipotential surfaces may facilitate non-conservative mass transfer in non-synchronous, eccentric binary star and planetary systems, especially if the component stars or planets are rotating super-synchronously at the periastron of their relative orbit. We also calculate the volume-equivalent radius of the Roche lobe as a function of the four parameters mentioned above. Contrary to common practice, we find that replacing the radius of a circular orbit in the fitting formula of Eggl...

  12. Acute effects of stretching on muscle stiffness after a bout of exhaustive eccentric exercise.

    Science.gov (United States)

    Torres, R; Appell, H-J; Duarte, J A

    2007-07-01

    With the aim to analyze the influence of stretching on muscle stiffness after eccentric exercise, 30 young men (18 - 32 years old), were divided into three groups: STR, undergoing a stretching program (SP) of the dominant quadriceps muscle, ECC, undergoing exhaustive eccentric exercise, and ECC/STR, undergoing eccentric exercise, followed by SP. Muscle stiffness (MS) was assessed immediately before the respective programs, and 1 and 24 hours after, measuring the following parameters during Wartenberg pendulum test: angle and angular velocity of first knee flexion (FKF) and following oscillating extension, time of oscillating movements and final resting knee angle (FRKA). Despite the slight (2%) but significant increase of FRKA, all further parameters did not change over time in STR. MS in ECC was documented by the reduced range of motion (ROM) and the slower angular velocity. Reduction in FRKA (10%) was still present after 24 hours, while other variables tended to recover eventually. Similar reduction in FKF was observed for ECC/STR, but with significantly less impairment in the range of pendulum movement one hour after the exercise and in tendency still remained less impaired 24 hours after. The results suggest that SP conducted after exhaustive eccentric exercise alleviated reductions in ROM induced by exercise.

  13. Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

    CERN Document Server

    Antoniadou, Kyriaki I

    2016-01-01

    Nowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's locat...

  14. Jupiter - Friend or Foe? IV: The influence of orbital eccentricity and inclination

    CERN Document Server

    Horner, J

    2011-01-01

    For many years, it was assumed that Jupiter prevented the Earth from being subject to a punishing impact regime that would greatly hinder the development of life. Here, we present the 4th in a series of studies investigating this hypothesis. Previously, we examined the effect of Jupiter's mass on the impact rate experienced by Earth. Here, we extend that approach to consider the influence of Jupiter's orbital eccentricity and inclination on the impact rate. We first consider scenarios in which Jupiter's orbital eccentricity was somewhat higher and somewhat lower than that in our Solar System. We find that Jupiter's orbital eccentricity plays a moderate role in determining the impact flux at Earth, with more eccentric orbits resulting in a higher impact rate of asteroids than for more circular orbits. This is particularly pronounced at high "Jupiter" masses. For short-period comets, the same effect is clearly apparent, albeit to a lesser degree. The flux of short-period comets impacting the Earth is slightly h...

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

    Science.gov (United States)

    Oliveira, Anderson Souza; Corvino, Rogério Bulhões; Caputo, Fabrizio; Aagaard, Per; Denadai, Benedito Sérgio

    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) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFDINC) or when normalised relative to MVC (RFDREL). After eight weeks, TG demonstrated increases in MVC (28%), RFDINC (0-50 ms: 30%; 50-100 ms: 31%) and RFDREL (0-50 ms: 29%; 50-100 ms: 32%). Moreover, 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 obtained at the early phase of rising joint torque.

  16. 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...

  17. Bearing Capacity Factors for Eccentrically Loaded Strip Footings Using Variational Analysis

    Directory of Open Access Journals (Sweden)

    Xinggao Li

    2013-01-01

    Full Text Available Bearing capacity factors for eccentrically loaded strip smooth footings on homogenous cohesive frictional material are deduced by the variational limit equilibrium method and by assuming general shear failure along continuous curved slip surface. From the calculated results, the effective width rule suggested by Meyerhof for bearing capacity factors due to cohesion of soil is justified, and the superposition principle of bearing capacity for eccentrically loaded strip smooth footings is derived together with the bearing capacity factors for cohesion and unit weight of soil. The two factors are represented by soil strength parameters and eccentricity of load. The bearing capacity factor related to unit weight for cohesionless soil is less than that for cohesive frictional soil. The reason for this discrepancy lies in the existence of the soil cohesion, for the shape of the critical rupture surface of footing soil depends on both soil strength parameters rather than on friction angle alone in the previous limit equilibrium solutions. The contact between footing and soil is decided by both the load and the mechanical properties of soil. Under conditions of higher eccentricity and less strength properties of soil, part of the footing will separate from the underlying soil.

  18. Effect of relative pile’s stiffness on lateral pile response under loading of large eccentricity

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole; Klinkvort, R.T.

    2015-01-01

    of the relative pile’s stiffness, when it is subjected to lateral load of large eccentricity. Employing centrifuge experiments, a hollow steel pile well instrumented with strain gauge pairs has been subjected to lateral load. The bending moment distribution of the model pile embedded in uniform, dense, dry sand...

  19. Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

    Science.gov (United States)

    Antoniadou, Kyriaki I.; Voyatzis, George

    2016-10-01

    Nowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's location.

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

    Science.gov (United States)

    de Wit, Julien; Lewis, Nikole K.; Knutson, Heather A.; Fuller, Jim; Antoci, Victoria; Fulton, Benjamin J.; Laughlin, Gregory; Deming, Drake; Shporer, Avi; Batygin, Konstantin; Cowan, Nicolas B.; Agol, Eric; Burrows, Adam S.; Fortney, Jonathan J.; Langton, Jonathan; Showman, Adam P.

    2017-02-01

    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 μm 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 μm 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.

  1. Roll Eccentricity Compensation Based on Anti-Alias-sing Wavelet Analysis Method

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-ming; LUO Fei; XU Yu-ge; YU Wei

    2009-01-01

    Roll eccentricity is an important factor causing thickness variations during hot strip rolling and might define the limit of strip thickness control accuracy. An improved multi-resolution wavelet transform algorithm was proposed to compensate for the roll eccentricity. The wavelet transform method had good localization characteristics in both the time and frequency domains for signal analysis; however, the wavelet method had a frequency-aliasing problem owing to the less than ideal cut-off frequency characteristics of wavelets. This made its component reconstruction of an inaccurate signal. To eliminate inherent frequency aliases in the wavelet transform, fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) were combined with the Mallat algorithm. This synthesis was described in detail. Then, the roll eccentricity component was extracted from rolling force signal. An automatic gauge control (AGC) system added with a multi-resolution wavelet analyzer was designed. Experimental results showed that the anti-aliasing method could greatly restrain the inverse effect of eccentricity and the thickness control accuracy was im-proved from ±40 μm to ±15 μm.

  2. Relationship Between Erectores Spinae Voltage and Back-Lift Strength for Isometric, Concentric, and Eccentric Contractions

    Science.gov (United States)

    Ashton, T. Edwin J.; Singh, Mohan

    1975-01-01

    This study determined the maximal mean values for concentric and eccentric back-lift strength as well as isometric, and examined and compared the relationships between the mean peak voltage of the erectores spinae muscle(s) and maximal force exerted for the three types of muscle contractions. (RC)

  3. The Eccentricity Distribution of Short-Period Planet Candidates Detected by Kepler in Occultation

    CERN Document Server

    Shabram, Megan; Cisewski, Jessi; Ford, Eric B; Rogers, Leslie

    2015-01-01

    We characterize the eccentricity distribution of a sample of ~50 short-period planet candidates using transit and occultation measurements from NASA's Kepler Mission. First, we evaluate the sensitivity of our hierarchical Bayesian modeling and test its robustness to model misspecification using simulated data. When analyzing actual data assuming a Rayleigh distribution for eccentricity, we find that the posterior mode for the dispersion parameter is $\\sigma=0.081 \\pm^{0.014}_{0.003}$. We find that a two-component Gaussian mixture model for $e \\cos \\omega$ and $e \\sin \\omega$ provides a better model than either a Rayleigh or Beta distribution. Based on our favored model, we find that $\\sim90\\%$ of planet candidates in our sample come from a population with an eccentricity distribution characterized by a small dispersion ($\\sim0.01$), and $\\sim10\\%$ come from a population with a larger dispersion ($\\sim0.22$). Finally, we investigate how the eccentricity distribution correlates with selected planet and host sta...

  4. The Eccentricity-Mass Distribution of Exoplanets: Signatures of Different Formation Mechanisms?

    CERN Document Server

    Ribas, I; Ribas, Ignasi; Miralda-Escude, Jordi

    2006-01-01

    We examine the distributions of eccentricity and host star metallicity of exoplanets as a function of their mass. Planets with M sin i >~ 4 M_J have an eccentricity distribution consistent with that of binary stars, while planets with M sin i <~ 4 M_J are less eccentric than binary stars and more massive planets. In addition, host star metallicities decrease with planet mass. The statistical significance of both of these trends is only marginal with the present sample of exoplanets. To account for these trends, we hypothesize that there are two populations of gaseous planets: the low-mass population forms by gas accretion onto a rock-ice core in a circumstellar disk and is more abundant at high metalliticities, and the high-mass population forms directly by fragmentation of a pre-stellar cloud. Planets of the first population form in initially circular orbits and grow their eccentricities later, and may have a mass upper limit from the total mass of the disk that can be accreted by the core. The second pop...

  5. 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.

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

    CERN Document Server

    Knispel, B; 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 ($e=0.08$) orbit in Pulsar ALFA survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3 $M_\\odot$ and is most likely a white dwarf. 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 larger eccentricities ($0.03 < e < 0.4$); PSR J1950+2414 is only the fifth such system to be discovered. The upper limits for the the intrinsic spin period derivative and inferred surface magnetic field strength are comparable to those of the general MSP population. The large eccentricities of these systems are not compatible with the predictions of the standard recycling scenario: som...

  7. On the formation of eccentric millisecond pulsars with helium white-dwarf companions

    CERN Document Server

    Antoniadis, John

    2014-01-01

    Millisecond pulsars (MSPs) orbiting helium white-dwarfs (WD) 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 (2014) recently proposed that these binary MSPs may instead form from the rotationally-delayed accretion-induced collapse of a massive WD. This scenario 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 (10^4-10^5 yrs disk can result to eccentricities of e ~ 0.01-0.15 for orbital per...

  8. 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.

  9. Reduced firing rates of high threshold motor units in response to eccentric overload.

    Science.gov (United States)

    Balshaw, Tom G; Pahar, Madhu; Chesham, Ross; Macgregor, Lewis J; Hunter, Angus M

    2017-01-01

    Acute responses of motor units were investigated during submaximal voluntary isometric tasks following eccentric overload (EO) and constant load (CL) knee extension resistance exercise. Ten healthy resistance-trained participants performed four experimental test sessions separated by 5 days over a 20 day period. Two sessions involved constant load and the other two used eccentric overload. EO and CL used both sessions for different target knee eccentric extension phases; one at 2 sec and the other at 4 sec. Maximal voluntary contractions (MVC) and isometric trapezoid efforts for 10 sec at 70% MVC were completed before and after each intervention and decomposed electromyography was used to measure motor unit firing rate. The firing rate of later recruited, high-threshold motor units declined following the 2-sec EO but was maintained following 2sec CL (P units were maintained for both loading types following 4-sec extension phases. MVC and rate of force development where maintained following both EO and CL and 2 and 4 sec phases. This study demonstrates a slower firing rate of high-threshold motor units following fast eccentric overload while MVC was maintained. This suggests that there was a neuromuscular stimulus without cost to the force-generating capacity of the knee extensors. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  10. Muscle Damage following Maximal Eccentric Knee Extensions in Males and Females.

    Directory of Open Access Journals (Sweden)

    K M Hicks

    Full Text Available To investigate whether there is a sex difference in exercise induced muscle damage.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.Patella tendon stiffness and Vastus Lateralis fascicle lengthening were significantly higher in males compared to females (p0.05. Creatine Kinase levels post exercise induced muscle damage were higher in males compared to females (p<0.05, and remained higher when maximal voluntary eccentric knee extension torque, relative to estimated quadriceps anatomical cross sectional area, was taken as a covariate (p<0.05.Based on isometric torque 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.

  11. On the Formation of Eccentric Millisecond Pulsars with Helium White-dwarf Companions

    Science.gov (United States)

    Antoniadis, John

    2014-12-01

    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 & 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 (104-105 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.

  12. Wandering saints : Chan eccentrics in the art and culture of Song and Yuan China

    NARCIS (Netherlands)

    Paul, Paramita

    2009-01-01

    In Chinese history, few personalities compare to the Chan eccentrics. These legendary, exceptional monks, including the friends Hanshan and Shide, their teacher Fenggan, and Budai, supposedly dwelled in the mountains and cities of southeast China between the seventh and tenth centuries. Dressed in r

  13. Skeletal muscle collagen content in humans after high-force eccentric contractions

    DEFF Research Database (Denmark)

    Mackey, Abigail; Donnelly, Alan E; Turpeenniemi-Hujanen, Taina

    2004-01-01

    4) yr] each performed a bout of 100 maximum voluntary eccentric contractions of the knee extensors. Muscle biopsies were taken before exercise and on days 4 and 22 afterward. Image analysis of stained tissue sections was used to quantify endomysial collagen staining intensity. Maximum voluntary...

  14. 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…

  15. Eccentricity in Images of Circular and Spherical Targets and its Impact to 3D Object Reconstruction

    Science.gov (United States)

    Luhmann, T.

    2014-06-01

    This paper discusses a feature of projective geometry which causes eccentricity in the image measurement of circular and spherical targets. While it is commonly known that flat circular targets can have a significant displacement of the elliptical image centre with respect to the true imaged circle centre, it can also be shown that the a similar effect exists for spherical targets. Both types of targets are imaged with an elliptical contour. As a result, if measurement methods based on ellipses are used to detect the target (e.g. best-fit ellipses), the calculated ellipse centre does not correspond to the desired target centre in 3D space. This paper firstly discusses the use and measurement of circular and spherical targets. It then describes the geometrical projection model in order to demonstrate the eccentricity in image space. Based on numerical simulations, the eccentricity in the image is further quantified and investigated. Finally, the resulting effect in 3D space is estimated for stereo and multi-image intersections. It can be stated that the eccentricity is larger than usually assumed, and must be compensated for high-accuracy applications. Spherical targets do not show better results than circular targets. The paper is an updated version of Luhmann (2014) new experimental investigations on the effect of length measurement errors.

  16. Influence of layer eccentricity on the resonant properties of cylindrical active coated nano-particles

    DEFF Research Database (Denmark)

    Thorsen, R. O.; Arslanagic, Samel

    2015-01-01

    We report on the influence of the layer eccentricity on the resonant properties of active coated nano-particles made of a silver core and gain impregnated silica shell illuminated by a near-by magnetic line source. For a fixed over-all size of the particle, designs with small and large cores...

  17. Habitability of planets on eccentric orbits: limits of the mean flux approximation

    Science.gov (United States)

    Bolmont, Emeline; Libert, Anne-Sophie; Leconte, Jérémy; Selsis, Franck; Turbet, Martin; Forget, François

    2016-04-01

    A few of the planets found in the insolation habitable zone (region in which a planet with an atmosphere can sustain surface liquid water, Kasting et al. 1993) are on eccentric orbits, such as GJ 667Cc (eccentricity of < 0.3, Anglada-Escude et al. 2012) or HD 16175 b (eccentricity of 0.6, Peek et al. 2009). This raises the question of the potential habitability of planets that only spend a fraction of their orbit in the habitable zone. Usually for a planet of semi-major axis a and eccentricity e, the averaged flux over one orbit received by the planet is considered. This averaged flux corresponds to the flux received by a planet on a circular orbit of radius r = a(1 -e2)1/4. If this orbital distance is within the habitable zone, the planet is said "habitable". However, for a hot star, for which the habitable zone is far from the star, the climate can be degraded when the planet is temporarily outside the habitable zone. We investigate here the limits of validity of the mean flux approximation used to assess the potential habitability of eccentric planets. For this study, we consider ocean planets in synchronized rotation and planets with a rotation period of 24 hr. We investigate the influence of the type of host star and the eccentricity of the orbit on the climate of a planet. We do so by scaling the duration of its orbital period and its apastron and periastron distance to ensure that it receives in average the same incoming flux as Earth's. We performed sets of 3D simulations using the Global Climate Model LMDz (Wordsworth et al. 2011, Forget et al. 2013, Leconte et al. 2013). The atmosphere is composed of N2, CO2 and H2O (gas, liquid, solid) in Earth-like proportions. First, we do not take into account the spectral difference between a low luminosity star and a Sun-like star. Second, the dependence of the albedo of ice and snow on the spectra of the host star is taken into account. This influences the positive ice-albedo feedback and can lead to a different

  18. 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

  19. 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

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

    Science.gov (United States)

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

    2015-06-01

    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 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. Key pointsA more dorsiflexed ankle and a flexing knee are characteristics of performing the flexed knee heel-drop eccentric exercise.Peak ankle plantarflexion moments were reduced with knee flexion, but did not reduce peak Achilles tendon force.Kinematic changes at the knee and ankle affected the triceps muscle length and resulted in a reduction in the amount of Achilles tendon work performed.A version of the heel-drop exercise which reduces the muscle length change will also reduce the amount of tendon stretch, reducing the clinical efficacy of the exercise.

  1. Residual force depression following muscle shortening is exaggerated by prior eccentric drop jump exercise.

    Science.gov (United States)

    Dargeviciute, Gintare; Masiulis, Nerijus; Kamandulis, Sigitas; Skurvydas, Albertas; Westerblad, Håkan

    2013-10-15

    We studied the relation between two common force modifications in skeletal muscle: the prolonged force depression induced by unaccustomed eccentric contractions, and the residual force depression (rFD) observed immediately after active shortening. We hypothesized that rFD originates from distortion within the sarcomeres and the extent of rFD: 1) correlates to the force and work performed during the shortening steps, which depend on sarcomeric integrity; and 2) is increased by sarcomeric disorganization induced by eccentric contractions. Nine healthy untrained men (mean age 26 yr) participated in the study. rFD was studied in electrically stimulated knee extensor muscles. rFD was defined as the reduction in isometric torque after active shortening compared with the torque in a purely isometric contraction. Eccentric contractions were performed as 50 repeated drop jumps with active deceleration to 90° knee angle, immediately followed by a maximal upward jump. rFD was assessed before and 5 min to 72 h after drop jumps. The series of drop jumps caused a prolonged force depression, which was about two times larger at 20-Hz than at 50-Hz stimulation. There was a significant correlation between increasing rFD and increasing mechanical work performed during active shortening both before and after drop jumps. In addition, a given rFD was obtained at a markedly lower mechanical work after drop jumps. In conclusion, the extent of rFD correlates to the mechanical work performed during active shortening. A series of eccentric contractions causes a prolonged reduction of isometric force. In addition, eccentric contractions exaggerate rFD, which further decreases muscle performance during dynamic contractions.

  2. Aging is not a barrier to muscle and redox adaptations: applying the repeated eccentric exercise model.

    Science.gov (United States)

    Nikolaidis, Michalis G; Kyparos, Antonios; Spanou, Chrysa; Paschalis, Vassilis; Theodorou, Anastasios A; Panayiotou, George; Grivas, Gerasimos V; Zafeiridis, Andreas; Dipla, Konstantina; Vrabas, Ioannis S

    2013-08-01

    Despite the progress of analytic techniques and the refinement of study designs, striking disagreement exists among studies regarding the influence of exercise on muscle function and redox homeostasis in the elderly. The repeated eccentric exercise model was applied to produce long-lasting and extensive changes in redox biomarkers and to reveal more effectively the potential effects of aging on redox homeostasis. Ten young (20.6±0.5 years) and ten elderly men (64.6±1.1 years) underwent an isokinetic eccentric exercise session, which was repeated after three weeks. Muscle function/damage indices (torque, range of movement, muscle soreness and creatine kinase) and redox biomarkers (F2-isoprostanes, protein carbonyls, glutathione, catalase, superoxide dismutase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, uric acid, bilirubin and albumin) were assessed in plasma, erythrocytes or urine pre-exercise, immediately post-exercise and at 2 and 4 days post-exercise. As expected, the elderly group exhibited oxidative stress in baseline compared to the young group. Extensive muscle damage and extensive alterations in redox homeostasis appeared after the first bout of eccentric exercise. Noteworthy, the redox responses were similar between the age groups despite their differences in baseline values. Likewise, both age groups demonstrated blunted alterations in muscle damage and redox homeostasis after the second bout of eccentric exercise indicating adaptations from the first bout of exercise. Elderly individuals seem to be well fitted to participate in demanding physical activities without suffering detrimental effects on skeletal muscle and/or disturbances on redox homeostasis. The repeated eccentric exercise model may be a useful and practical physiological tool to study redox biology in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Maximal force, voluntary activation and muscle soreness after eccentric damage to human elbow flexor muscles

    Science.gov (United States)

    Prasartwuth, O; Taylor, JL; Gandevia, SC

    2005-01-01

    Muscle damage reduces voluntary force after eccentric exercise but impaired neural drive to the muscle may also contribute. To determine whether the delayed-onset muscle soreness, which develops ∼1 day after exercise, reduces voluntary activation and to identify the possible site for any reduction, voluntary activation of elbow flexor muscles was examined with both motor cortex and motor nerve stimulation. We measured maximal voluntary isometric torque (MVC), twitch torque, muscle soreness and voluntary activation in eight subjects before, immediately after, 2 h after, 1, 2, 4 and 8 days after eccentric exercise. Motor nerve stimulation and motor cortex stimulation were used to derive twitch torques and measures of voluntary activation. Eccentric exercise immediately reduced the MVC by 38 ± 3% (mean ±s.d., n = 8). The resting twitch produced by motor nerve stimulation fell by 82 ± 6%, and the estimated resting twitch by cortical stimulation fell by 47 ± 15%. While voluntary torque recovered after 8 days, both measures of the resting twitch remained depressed. Muscle tenderness occurred 1–2 days after exercise, and pain during contractions on days 1–4, but changes in voluntary activation did not follow this time course. Voluntary activation assessed with nerve stimulation fell 19 ± 6% immediately after exercise but was not different from control values after 2 days. Voluntary activation assessed by motor cortex stimulation was unchanged by eccentric exercise. During MVCs, absolute increments in torque evoked by nerve and cortical stimulation behaved differently. Those to cortical stimulation decreased whereas those to nerve stimulation tended to increase. These findings suggest that reduced voluntary activation contributes to the early force loss after eccentric exercise, but that it is not due to muscle soreness. The impairment of voluntary activation to nerve stimulation but not motor cortical stimulation suggests that the activation deficit lies in the

  4. Temporal Pattern of the Repeated Bout Effect of Eccentric Exercise on Delayed-Onset Muscle Soreness

    Science.gov (United States)

    Cleary, Michelle A.; Kimura, Iris F.; Sitler, Michael R.; Kendrick, Zebulon V.

    2002-01-01

    Objective: To determine the temporal pattern of the repeated bout effect of eccentric exercise on perceived pain and muscular tenderness associated with delayed-onset muscle soreness (DOMS). Design and Setting: Subjects completed 2 identical eccentric exercise bouts separated by 6, 7, 8, or 9 weeks. The experiment was conducted in a biokinetics research laboratory. Subjects: Sixteen male and 15 female untrained subjects (age = 24.59 ± 4.42 years, height = 171.71 ± 7.81 cm, weight = 73.00 ± 11.20 kg). Measurements: Two physiologic characteristics of DOMS were measured immediately before and 0, 24, 48, and 72 hours after each eccentric exercise bout. Perceived pain was measured using a visual analog scale (VAS), and muscular tenderness was measured using a punctate tenderness gauge (PTG). Results: Two 4 × 2 × 5 (group × bout × time) analyses of variance with repeated measures on the bout and time factors were performed on the VAS and PTG data. Significant (P < .05) main effects were found for group, bout, and time for the VAS and the PTG data. No significant interactions were detected. Post hoc analysis revealed significantly less perceived pain for the 9-week group than the 8-week group. The 7-week group had significantly less and the 8-week group had significantly more muscular tenderness than any other group. Perceived pain and muscular tenderness were significantly less after exercise bout 2 than after exercise bout 1. All subjects had significantly less perceived pain and muscular tenderness pre-exercise than 0 and 24 hours after the eccentric exercise bouts. Conclusions: An effective prophylaxis for perceived pain and muscular tenderness associated with DOMS is the performance of an eccentric exercise bout 6 to 9 weeks before a similar exercise bout. PMID:12937441

  5. FKBP12 deficiency reduces strength deficits after eccentric contraction-induced muscle injury

    Science.gov (United States)

    Corona, Benjamin T.; Rouviere, Clement; Hamilton, Susan L.; Ingalls, Christopher P.

    2008-01-01

    Strength deficits associated with eccentric contraction-induced muscle injury stem, in part, from excitation-contraction uncoupling. FKBP12 is a 12-kDa binding protein known to bind to the skeletal muscle sarcoplasmic reticulum Ca2+ release channel [ryanodine receptor (RyR1)] and plays an important role in excitation-contraction coupling. To assess the effects of FKBP12 deficiency on muscle injury and recovery, we measured anterior crural muscle (tibialis anterior and extensor digitorum longus muscles) strength in skeletal muscle-specific FKBP12-deficient and wild-type (WT) mice before and after a single bout of 150 eccentric contractions, as well as before and after the performance of six injury bouts. Histological damage of the tibialis anterior muscle was assessed after injury. Body weight and peak isometric and eccentric torques were lower in FKBP12-deficient mice compared with WT mice. There were no differences between FKBP12-deficient and WT mice in preinjury peak isometric and eccentric torques when normalized to body weight, and no differences in the relative decreases in eccentric torque with a single or multiple injury bouts. After a single injury bout, FKBP12-deficient mice had less initial strength deficits and recovered faster (especially females) than WT mice, despite no differences in the degree of histological damage. After multiple injury bouts, FKBP12-deficient mice recovered muscle strength faster than WT mice and exhibited significantly less histological muscle damage than WT mice. In summary, FKBP12 deficiency results in less initial strength deficits and enhanced recovery from single (especially females) and repeated bouts of injury than WT mice. PMID:18511525

  6. Tidal dissipation and eccentricity pumping: Implications for the depth of the secondary eclipse of 55 Cnc e

    CERN Document Server

    Bolmont, Emeline; Raymond, Sean N; Leconte, Jeremy; Hersant, Franck; Maurin, Anne-Sophie; Pericaud, Jessica

    2013-01-01

    We use the super Earth 55 Cnc e as a case study to address an observable effect of tidal heating. We investigate whether planet-planet interactions can force the eccentricity of this planet to a level affecting the eclipse depth observed with Spitzer. Using the constant time lag tidal model, we first calculate the observed planet flux as a function of albedo and eccentricity, for different tidal dissipation constants and for two extreme cases: a planet with no heat redistribution and a planet with full heat redistribution. We derive the values of albedo and eccentricity that match the observed transit depth. We then perform N-body simulations of the planetary system including tides and General Relativity to follow the evolution of the eccentricity of planet e. We compare the range of eccentricities given by the simulations with the eccentricities required to alter the eclipse depth. We find that the eccentricity of planet e can be large enough to contribute at a measurable level to the thermal emission measur...

  7. Alterations in Whole-Body Insulin Sensitivity Resulting From Repeated Eccentric Exercise of a Single Muscle Group: A Pilot Investigation.

    Science.gov (United States)

    Gonzalez, Javier T; Barwood, Martin J; Goodall, Stuart; Thomas, Kevin; Howatson, Glyn

    2015-08-01

    Unaccustomed eccentric exercise using large muscle groups elicits soreness, decrements in physical function and impairs markers of whole-body insulin sensitivity; although these effects are attenuated with a repeated exposure. Eccentric exercise of a small muscle group (elbow flexors) displays similar soreness and damage profiles in response to repeated exposure. However, it is unknown whether damage to small muscle groups impacts upon whole-body insulin sensitivity. This pilot investigation aimed to characterize whole-body insulin sensitivity in response to repeated bouts of eccentric exercise of the elbow flexors. Nine healthy males completed two bouts of eccentric exercise separated by 2 weeks. Insulin resistance (updated homeostasis model of insulin resistance, HOMA2-IR) and muscle damage profiles (soreness and physical function) were assessed before, and 48 h after exercise. Matsuda insulin sensitivity indices (ISI Matsuda) were also determined in 6 participants at the same time points as HOMA2-IR. Soreness was elevated, and physical function impaired, by both bouts of exercise (both p Eccentric exercise decreased ISI Matsuda after the first but not the second bout of eccentric exercise (time x bout interaction p Eccentric exercise performed with an isolated upper limb impairs whole-body insulin sensitivity after the first, but not the second, bout.

  8. A New Secular Instability of Eccentric Stellar Disks Around Supermassive Black Holes, With Application to the Galactic Center

    CERN Document Server

    Madigan, Ann-Marie; Hopman, Clovis

    2008-01-01

    We identify a new secular instability of eccentric stellar disks around supermassive black holes. We show that retrograde precession of the stellar orbits, due to the presence of a stellar cusp, induces coherent torques that amplify deviations of individual orbital eccentricities from the average, and thus drive all eccentricities away from their initial value. We investigate the instability using N-body simulations, and show that it can drive individual orbital eccentricities to significantly higher or lower values on the order of a precession time-scale. This physics is relevant for the Galactic center, where massive stars are likely to form in eccentric disks around the SgrA* black hole. We show that the dynamical evolution of such a disk results in several of its stars acquiring high (1-e << 0.1) orbital eccentricity. Binary stars on such highly eccentric orbits would get tidally disrupted by the SgrA* black hole, possibly producing both S-stars near the black hole and high-velocity stars in the Gal...

  9. Limiting eccentricity of sub-parsec massive black hole binaries surrounded by self-gravitating gas discs

    CERN Document Server

    Rödig, Constanze; Sesana, Alberto; Cuadra, Jorge; Colpi, Monica

    2011-01-01

    We study the dynamics of supermassive black hole binaries embedded in circumbinary gaseous discs, with the SPH code Gadget-2. The sub-parsec binary (of total mass M and mass ratio q=1/3) has excavated a gap and transfers its angular momentum to the self--gravitating disc (M_disc=0.2 M). We explore the changes of the binary eccentricity e, by simulating a sequence of binary models that differ in the initial eccentricity e_0, only. In initially low-eccentric binaries, the eccentricity increases with time, while in high-eccentric binaries e declines, indicating the existence of a limiting eccentricity e_crit that is found to fall in the interval [0.6,0.8]. We also present an analytical interpretation for this saturation limit. An important consequence of the existence of e_crit is the detectability of a significant residual eccentricity e_LISA} by the proposed gravitational wave detector LISA. It is found that at the moment of entering the LISA frequency domain e_LISA ~ 10^{-3}-10^{-2}; a signature of its earlie...

  10. Analysis of concentric and eccentric contractions in biceps brachii muscles using surface electromyography signals and multifractal analysis.

    Science.gov (United States)

    Marri, Kiran; Swaminathan, Ramakrishnan

    2016-06-23

    Muscle contractions can be categorized into isometric, isotonic (concentric and eccentric) and isokinetic contractions. The eccentric contractions are very effective for promoting muscle hypertrophy and produce larger forces when compared to the concentric or isometric contractions. Surface electromyography signals are widely used for analyzing muscle activities. These signals are nonstationary, nonlinear and exhibit self-similar multifractal behavior. The research on surface electromyography signals using multifractal analysis is not well established for concentric and eccentric contractions. In this study, an attempt has been made to analyze the concentric and eccentric contractions associated with biceps brachii muscles using surface electromyography signals and multifractal detrended moving average algorithm. Surface electromyography signals were recorded from 20 healthy individuals while performing a single curl exercise. The preprocessed signals were divided into concentric and eccentric cycles and in turn divided into phases based on range of motion: lower (0°-90°) and upper (>90°). The segments of surface electromyography signal were subjected to multifractal detrended moving average algorithm, and multifractal features such as strength of multifractality, peak exponent value, maximum exponent and exponent index were extracted in addition to conventional linear features such as root mean square and median frequency. The results show that surface electromyography signals exhibit multifractal behavior in both concentric and eccentric cycles. The mean strength of multifractality increased by 15% in eccentric contraction compared to concentric contraction. The lowest and highest exponent index values are observed in the upper concentric and lower eccentric contractions, respectively. The multifractal features are observed to be helpful in differentiating surface electromyography signals along the range of motion as compared to root mean square and median

  11. 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.

  12. NUMERICAL SIMULATION OF UNSTEADY FLOW FOR VISCO-ELASTIC FLUID IN AN ECCENTRIC ANNULUS WITH INNER ROD RECIPROCATION

    Institute of Scientific and Technical Information of China (English)

    HE Feng-yun; YANG Shu-ren

    2008-01-01

    The equation governing the unsteady flow of viscoelastic fluids in an eccentric annulus was derived by using the common conversion Maxwell fluid constitutive equation and then discretized by the control volume method. The velocity distribution of flow field was computed by using the ADI method. The influences of the pressure gradient, eccentricity, stroke length, and stroke frequency on the velocity and flow capacity in the flow field was analyzed. The foundation for further research of the eccentric wear problem of the pumping rod in polymer-flood well was laid.

  13. Friction and Wear Reduction of Eccentric Journal Bearing Made of Sn-Based Babbitt for Ore Cone Crusher

    OpenAIRE

    Auezhan Amanov; Byungmin Ahn; Moon Gu Lee; Yongho Jeon; Young-Sik Pyun

    2016-01-01

    An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lubricant, it suffers from mining environments and short service life. In this study, an ultrasonic na...

  14. 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; dos Santos, Paulo Roberto Dias; dos Santos, Bruno Schiefer; Carrazzone, Oreste Lemos; Peixoto, Gabriel; Aoyama, Bruno Takeshi; Tamaoki, Marcel Jun Sugawara

    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 eccentric strengthening protocol, will improve measures of pain and function. Design Double blind, placebo-controlled, parallel groups, randomised clinical trial. Materials and methods 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. Discussion 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

  15. Unilateral eccentric resistance training: A direct comparison between isokinetic and dynamic constant external resistance modalities.

    Science.gov (United States)

    Coratella, Giuseppe; Milanese, Chiara; Schena, Federico

    2015-01-01

    Aim of the study was to compare the effects of unilateral eccentric-only training using constant velocity vs. constant external load. Forty-seven participants were randomized in isokinetic (IK), dynamic constant external resistance (DCER) unilateral eccentric training or control groups. Knee extension 1RM and isometric, eccentric and concentric knee extensors peak torque, as well as changes in vastus lateralis fascicle pennation angle, fascicle length, muscle thickness, and quadriceps fat-free mass were measured. Both IK and DCER training consisted in 5 × 8 eccentric-only repetitions, 2d/w, for 6 weeks. IK and DCER training sessions were matched for total volume. After training, both IK and DCER similarly increased 1RM (respectively, +4.4 kg, CI95% 1.8-7.0 and +5.5 kg, CI95% 3.3-7.9), isometric (respectively, +34.5 N/m, CI95% 23.0-45.9 and +15.8, CI95% 5.4-26.2) and concentric peak torque (respectively, +17.0 N/m, CI95% 6.6 to +27.4 and 12.2 CI95% 2.8-21.7). IK increased eccentric peak torque significantly more than DCER (respectively, +84.2 N/m, CI95% 66.3-102.1 and +38.2 N/m, CI95% 21.9-54.4). Both IK and DCER similarly increased fascicle length (respectively, +14.7 mm, CI95% 5.4-24.0 and +14.4 mm, CI95% 5.4-23.3) and muscle thickness (respectively, +3.3 mm, CI95% 1.5-5.1, and +4.1 mm, CI95% 2.5-5.7). Matching the training volume resulted in similar adaptations comparing eccentric-only IK or DCER resistance training. Both in rehabilitation and in training practice, the use of easily available gym devices can be a good substitute for expensive and often unavailable IK devices.

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

    Science.gov (United States)

    2012-01-01

    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 eccentric torque was observed 12 hours following exercise in both treatment groups. During the 60 hour recovery period, a significant (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 exercise and interestingly coincided with a gradual increase in plasma antioxidant capacity, whereas biomarkers for inflammation were still elevated after 60 hours recovery. Conclusions This study demonstrates that the ingestion of a blueberry smoothie prior to and after EIMD accelerates

  17. Highly inclined and eccentric massive planets. II. Planet-planet interactions during the disc phase

    Science.gov (United States)

    Sotiriadis, Sotiris; Libert, Anne-Sophie; Bitsch, Bertram; Crida, Aurélien

    2017-02-01

    Context. Observational evidence indicates that the orbits of extrasolar planets are more various than the circular and coplanar ones of the solar system. Planet-planet interactions during migration in the protoplanetary disc have been invoked to explain the formation of these eccentric and inclined orbits. However, our companion paper (Paper I) on the planet-disc interactions of highly inclined and eccentric massive planets has shown that the damping induced by the disc is significant for a massive planet, leading the planet back to the midplane with its eccentricity possibly increasing over time. Aims: We aim to investigate the influence of the eccentricity and inclination damping due to planet-disc interactions on the final configurations of the systems, generalizing previous studies on the combined action of the gas disc and planet-planet scattering during the disc phase. Methods: Instead of the simplistic K-prescription, our N-body simulations adopt the damping formulae for eccentricity and inclination provided by the hydrodynamical simulations of our companion paper. We follow the orbital evolution of 11 000 numerical experiments of three giant planets in the late stage of the gas disc, exploring different initial configurations, planetary mass ratios and disc masses. Results: The dynamical evolutions of the planetary systems are studied along the simulations, with a particular emphasis on the resonance captures and inclination-growth mechanisms. Most of the systems are found with small inclinations (≤ 10°) at the dispersal of the disc. Even though many systems enter an inclination-type resonance during the migration, the disc usually damps the inclinations on a short timescale. Although the majority of the multiple systems in our simulations are quasi-coplanar, 5% of them end up with high mutual inclinations (≥ 10°). Half of these highly mutually inclined systems result from two- or three-body mean-motion resonance captures, the other half being

  18. 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).

  19. Methods for determination of ultimate load of eccentrically patch loaded steel I-girders

    Directory of Open Access Journals (Sweden)

    Šćepanović, B.

    2014-12-01

    Full Text Available Experimental tests show that most eccentrically patch loaded steel I-girders have a collapse mode quite different from that of centrically loaded girders. Concerning engineering practice, the most important difference between collapse modes is in ultimate load. The reduction in ultimate load with an increase in load eccentricity is obvious in some eccentrically loaded girders. Under certain circumstances, for a certain combination of influential parameters, eccentrically loaded girders behave as if loaded in the web plane, with no or no significant reduction in ultimate load due to load eccentricity. Dealing with such a big number of mutually dependant parameters that influence collapse mode and level of ultimate load reduction due to load eccentricity, still without theoretical formulation of collapse mechanism, two approaches for ultimate load determination are analysed: empirical mathematical expressions and artificial neural networks forecast models. Results of two procedures are compared. Recommendations for application in engineering practice are given.Las pruebas experimentales muestran que la mayoría de vigas en I de acero cargadas excéntricamente tienen un modo de colapso muy diferente del de las vigas cargadas centradas. En cuanto a la práctica de ingeniería, la diferencia más importante entre los modos de colapso es la carga final. La reducción de la carga última con un aumento de la excentricidad de carga es evidente en algunas vigas cargadas excéntricamente, mientras que bajo ciertas circunstancias, para una determinada combinación de parámetros influyentes, las vigas cargadas excéntricamente se comportan como si se carga en el plano del alma, con ninguna reducción significativa en la carga última debido a la carga excéntrica. Se analizan dos métodos para la determinación de la carga máxima: expresiones matemáticas empíricas y redes neuronales artificiales. Los resultados de ambos procedimientos se comparan. Se

  20. Eccentricity fluctuations make flow measurable in high multiplicity p-p collisions

    CERN Document Server

    Casalderrey-Solana, Jorge

    2010-01-01

    Elliptic flow is a hallmark of collectivity in hadronic collisions. Its measurement relies on analysis techniques which require high event multiplicity and could be applied so far to heavy ion collisions only. Here, we delineate the conditions under which elliptic flow becomes measurable in the samples of high-multiplicity ($dN_{\\rm ch}/dy \\geq 50$) p-p collisions, which will soon be collected at the LHC. We observe that fluctuations in the p-p interaction region can result in a sizable spatial eccentricity even for the most central p-p collisions. Under relatively mild assumptions on the nature of such fluctuations and on the eccentricity scaling of elliptic flow, we find that the resulting elliptic flow signal in high-multiplicity p-p collisions at the LHC becomes measurable with standard techniques.

  1. Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running

    DEFF Research Database (Denmark)

    Oliveira, Anderson S. C.; Caputo, Fabrizio; Aagaard, Per

    2013-01-01

    The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective...... effects against muscle fatigue and ultrastructural damages, preventing or reducing the loss in mechanical muscle function after running. Subjects were tested before and after IERT protocol for maximal isometric, concentric and eccentric isokinetic knee extensor strength (60° and 180° s(-1)). In a second...... session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n...

  2. Position sense and reaction angle after eccentric exercise: the repeated bout effect.

    Science.gov (United States)

    Paschalis, V; Nikolaidis, M G; Giakas, G; Jamurtas, A Z; Owolabi, E O; Koutedakis, Y

    2008-05-01

    The purpose of the present investigation was to examine the effects of a repeated eccentric exercise on position sense and muscle reaction angle. Fourteen healthy women underwent an isokinetic exercise session on their knee flexors, which was repeated after 4 weeks. Muscle damage indices, position sense and joint reaction angle of the knee were examined before, immediately after, as well as at 1, 2, 3, 4 and 7 days after exercise. The second exercise bout induced significantly lesser effects in all muscle damage indices as well as lesser disturbances in position sense and reaction angle when compared to the first one. The main finding of this study is that position sense and joint reaction angle to release of the lower limbs may adapt in response to a repeated bout of eccentric exercise, leading to less disturbances in position sense and reaction angle after the second bout of exercise.

  3. Orbital stability zones about asteroids. II - The destabilizing effects of eccentric orbits and of solar radiation

    Science.gov (United States)

    Hamilton, Douglas P.; Burns, Joseph A.

    1992-03-01

    Recently, Hamilton and Burns (1991) characterized the size and shape of a stability zone around an asteroid on a circular heliocentric orbit within which asteroid material could remain bound for an extended period of time. The present paper considers two additional effects: the asteroid's nonzero heliocentric eccentricity and solar radiation pressure. Results of numerical analyses show that, for an asteroid on an eccentric orbit, the stability zone scales roughly as the size of the Hill sphere calculated at the asteroid's pericenter. It was also found that solar radiation pressure is a very efficient mechanism for removing small (on the order of 0.1 mm) particles from circular asteroidal zone. Particles larger than a few centimeters are only slightly affected by radiation pressure. The results are applied to the Gaspra 951 asteroid.

  4. The 2D surfaces that generate Newtonian and general relativistic orbits with small eccentricities

    CERN Document Server

    Middleton, Chad A

    2015-01-01

    Embedding diagrams prove to be quite useful when learning general relativity as they offer a way of visualizing spacetime curvature through warped two dimensional (2D) surfaces. In this manuscript we present a different 2D construct that also serves as a useful conceptual tool for gaining insight into gravitation, in particular, orbital dynamics - namely the cylindrically symmetric surfaces that generate Newtonian and general relativistic orbits with small eccentricities. Although we first show that no such surface exists that can exactly reproduce the arbitrary bound orbits of Newtonian gravitation or of general relativity (or, more generally, of any spherically symmetric potential), surfaces do exist that closely approximate the resulting orbital motion for small eccentricities; exactly the regime that describes the motion of the solar system planets. These surfaces help to illustrate the similarities, as well as the differences, between the two theories of gravitation (i.e. stationary elliptical orbits in ...

  5. 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........96 +/- 0.44 ng ml(-1), day 2: 1.94 +/- 0.32 ng ml(-1), day 4: 3.90 +/- 1.03 ng ml(-1), day 8: 7.23 +/- 2.34 ng ml(-1)*, *P exercise, an increase in the histological immunoreactivity of PINP and the N...

  6. 圆锥曲线中的离心率问题%Eccentricity in Conic Section

    Institute of Scientific and Technical Information of China (English)

    范增康

    2011-01-01

    In daily exercises and exams, most calculation of eccentricity is the solution to numerical problems, and it is not realistic to mechanically apply ready-made eccentricity formula to solve problems. This paper throws some light on the evaluation of eceentricity and numeric area in conic section.%在平时的练习或考试中,有关离心率的计算,多数是数值问题的求解,想套用现成的离心率公式进行解答并不现实。本文就是围绕圆锥曲线中离心率求值和求取值范围问题具体展开阐述。

  7. 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.

  8. A Novel Approach for Eccentricity Fault Detection in Squirrel Cage Induction Motors

    Directory of Open Access Journals (Sweden)

    Mehdi Ahmadi

    2013-01-01

    Full Text Available In this paper, static eccentricity fault detection in induction motors is studied. Two dimensional finite element method (2D-FEM is used for faultless and eccentric condition modeling in induction motors. Also current and speed signals are compared in two experimental and simulation cases for model validating. For fault detection, fast Fourier transform is used at first. In this method, high order harmonics with small amplitude can alarms the fault occurrence. For this reason, the fault detection process is difficult.To overcome these drawbacks, it is suggested that two test coils contrive around the air-gap. So, any changes in air-gap can be detected easily. Moreover this test coils are used in open circuit case. So, these test coils do not effect on motor dynamics. Also, the results show that modulated voltage can be alarm the fault occurrence, type and percent well.

  9. 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.

  10. 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.

  11. Liquid Sloshing in a Horizontal Circular Container with Eccentric Tube under External Excitation

    Directory of Open Access Journals (Sweden)

    Mohammad Nezami

    2014-01-01

    Full Text Available Appropriate conformal mapping transformation in combination with the linear potential theory is employed to develop mathematical model for two-dimensional sloshing in horizontal circular cylindrical containers with overall eccentric hole. The tube-type tank is filled with inviscid incompressible fluid up to its half depth and subjected to lateral accelerations. A ramp-step excitation encountered in a road turning maneuver as well as real seismic event is used to simulate the lateral acceleration excitation. The resulting linear sets of ordinary differential equations are truncated and then solved numerically by employing Laplace transform technique followed by Durbin’s numerical inversion pattern. The effects of excitation input time, eccentricity, and radii ratio on the hydrodynamic responses and suppression of the induced destabilizing lateral forces are examined. Limiting cases are considered and good agreements with available analytic and numerical solutions as well as the simulations performed by using a commercial FEM software package are obtained.

  12. Mass and eccentricity constraints on the planetary debris orbiting the white dwarf WD 1145+017

    CERN Document Server

    Gurri, Pol; Gänsicke, Boris T

    2016-01-01

    Being the first of its kind, the white dwarf WD 1145+017 exhibits a complex system of disintegrating debris which offers a unique opportunity to study its disruption process in real time. Even with plenty of transit observations there are no clear constraints on the masses or eccentricities of such debris. Using $N$-body simulations we show that masses greater than approximately $10^{20}$ kg (a tenth of the mass of Ceres) or orbits that are not nearly circular ($\\mathrm{eccentricity}>10^{-3}$) dramatically increase the chances of the system becoming unstable within two years, which would contrast with the observational data over this timespan. We also provide a direct comparison between transit phase shifts detected in the observations and by our numerical simulations.

  13. Empirical explanation of the anomalous increases of the astronomical unit and of the lunar eccentricity

    CERN Document Server

    Iorio, Lorenzo

    2011-01-01

    Both the recently reported anomalous secular increase of the astronomical unit, of the order of a few cm yr^-1, and of the eccentricity of the lunar orbit e_ = (9+/-3) 10^-12 yr^-1 can be phenomenologically explained by postulating that the acceleration of a test particle orbiting a central body, in addition to usual Newtonian component, contains a small additional radial term proportional to the radial projection vr of the velocity of the particle's orbital motion. Indeed, it induces secular variations of both the semi-major axis a and the eccentricity e of the test particle's orbit. In the case of the Earth and the Moon, they numerically agree rather well with the measured anomalies if one takes the numerical value of the coefficient of proportionality of the extra-acceleration approximately equal to that of the Hubble parameter H0 = 7.3 10^-11 yr^-1.

  14. Apocenter glow in eccentric debris disks: implications for Fomalhaut and $\\epsilon$ Eridani

    CERN Document Server

    Pan, Margaret; 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 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 ACTA should be reinterpreted as suggestions or examples of apocenter glow. This reinterpretation yields new constraints on the disks' dust grain properties and size distributions.

  15. 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

    and cytoskeletal protein fractions. The first bout of exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P ... 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...... eccentric exercise bout. Our results show that HSP translocation and expression responses are induced by muscle damaging exercise, and suggest that such HSP responses are closely related to the extent of muscle damage Udgivelsesdato: 2009/7...

  16. SECRETLY ECCENTRIC: THE GIANT PLANET AND ACTIVITY CYCLE OF GJ 328

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J. [Department of Astronomy and McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Boss, Alan P., E-mail: paul@astro.as.utexas.edu [Department of Terrestrial Magnetism, Carnegie Institution, 5241 Broad Branch Road, NW, Washington DC 20015-1305 (United States)

    2013-09-10

    We announce the discovery of a {approx}2 Jupiter-mass planet in an eccentric 11 yr orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m s{sup -1}. After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf.

  17. Secretly Eccentric: The Giant Planet and Activity Cycle of GJ 328

    CERN Document Server

    Robertson, Paul; Cochran, William D; MacQueen, Phillip J; Boss, Alan P

    2013-01-01

    We announce the discovery of a ~2 Jupiter-mass planet in an eccentric 11-year orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years' worth of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m/s. After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf.

  18. Is tidal heating sufficient to explain bloated exoplanets? Consistent calculations accounting for finite initial eccentricity

    CERN Document Server

    Leconte, Jérémy; Baraffe, Isabelle; Levrard, Benjamin

    2010-01-01

    In this paper, we present the consistent evolution of short-period exoplanets coupling the tidal and gravothermal evolution of the planet. Contrarily to previous similar studies, our calculations are based on the complete tidal evolution equations of the Hut model, valid at any order in eccentricity, obliquity and spin. We demonstrate, both analytically and numerically, that, except if the system was formed with a nearly circular orbit (e<0.2), solving consistently the complete tidal equations is mandatory to derive correct tidal evolution histories. We show that calculations based on tidal models truncated at second order in eccentricity, as done in all previous studies, lead to erroneous tidal evolutions. As a consequence, tidal energy dissipation rates are severely underestimated in all these calculations and the characteristic timescales for the various orbital parameters evolutions can be wrong by up to three orders in magnitude. Based on these complete, consistent calculations, we revisit the viabili...

  19. Formation of terrestrial planets in eccentric and inclined giant-planet systems

    Science.gov (United States)

    Sotiriadis, Sotiris; Libert, Anne-Sophie; Raymond, Sean

    2016-10-01

    The orbits of extrasolar planets are more various than the circular and coplanar ones of the Solar system. We study the impact of inclined and eccentric massive giant planets on the terrestrial planet formation process. The physical and orbital parameters of the giant planets considered in this study arise from n-body simulations of three giant planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. At the dispersal of the gas disc, the two- and three-planet systems interact then with an inner disc of planetesimals and planetary embryos. We discuss the mass and orbital parameters of the terrestrial planets formed by our simulations, as well as their water content. We also investigate how the disc of planetesimals and planetary embryos modifies the eccentric and inclined orbits of the giant planets.

  20. Pacemaking the ice ages by frequency modulation of Earth's orbital eccentricity

    Science.gov (United States)

    Rial

    1999-07-23

    Evidence from power spectra of deep-sea oxygen isotope time series suggests that the climate system of Earth responds nonlinearly to astronomical forcing by frequency modulating eccentricity-related variations in insolation. With the help of a simple model, it is shown that frequency modulation of the approximate 100,000-year eccentricity cycles by the 413,000-year component accounts for the variable duration of the ice ages, the multiple-peak character of the time series spectra, and the notorious absence of significant spectral amplitude at the 413,000-year period. The observed spectra are consistent with the classic Milankovitch theories of insolation, so that climate forcing by 100,000-year variations in orbital inclination that cause periodic dust accretion appear unnecessary.