Microscopic models of quantum-jump superoperators
International Nuclear Information System (INIS)
Dodonov, A.V.; Mizrahi, S.S.; Dodonov, V.V.
2005-01-01
We discuss the quantum-jump operation in an open system and show that jump superoperators related to a system under measurement can be derived from the interaction of that system with a quantum measurement apparatus. We give two examples for the interaction of a monochromatic electromagnetic field in a cavity (the system) with two-level atoms and with a harmonic oscillator (representing two different kinds of detectors). We show that the derived quantum-jump superoperators have a 'nonlinear' form Jρ=γ diag[F(n)aρa † F(n)], where the concrete form of the function F(n) depends on assumptions made about the interaction between the system and detector. Under certain conditions the asymptotical power-law dependence F(n)=(n+1) -β is obtained. A continuous transition to the standard Srinivas-Davies form of the quantum-jump superoperator (corresponding to β=0) is shown
Decoherence in quantum lossy systems: superoperator and matrix techniques
Yazdanpanah, Navid; Tavassoly, Mohammad Kazem; Moya-Cessa, Hector Manuel
2017-06-01
Due to the unavoidably dissipative interaction between quantum systems with their environments, the decoherence flows inevitably into the systems. Therefore, to achieve a better understanding on how decoherence affects on the damped systems, a fundamental investigation of master equation seems to be required. In this regard, finding out the missed information which has been lost due to irreversibly of the dissipative systems, is also of practical importance in quantum information science. Motivating by these facts, in this work we want to use superoperator and matrix techniques, by which we are able to illustrate two methods to obtain the explicit form of density operators corresponding to damped systems at arbitrary temperature T ≥ 0. To establish the potential abilities of the suggested methods, we apply them to deduce the density operator of some practical well-known quantum systems. Using the superoperator techniques, at first we obtain the density operator of a damped system which includes a qubit interacting with a single-mode quantized field within an optical cavity. As the second system, we study the decoherence of a quantized field within an optical damped cavity. We also use our proposed matrix method to study the decoherence of a system which includes two qubits in the interaction with each other via dipole-dipole interaction and at the same time with a quantized field in a lossy cavity. The influences of dissipation on the decoherence of dynamical properties of these systems are also numerically investigated. At last, the advantages of the proposed superoperator techniques in comparison with matrix method are explained.
International Nuclear Information System (INIS)
Cook, R.J.
1988-01-01
This paper answers the title question by giving an operational definition of quantum jumps based on measurement theory. This definition forms the basis of a theory of quantum jumps which leads to a number of testable predictions. Experiments are proposed to test the theory. The suggested experiments also test the quantum Zeno paradox, i.e., they test the proposition that frequent observation of a quantum system inhibits quantum jumps in that system. (orig.)
Timeless Approach to Quantum Jumps
Directory of Open Access Journals (Sweden)
Ignazio Licata
2015-10-01
Full Text Available According to the usual quantum description, the time evolution of the quantum state is continuous and deterministic except when a discontinuous and indeterministic collapse of state vector occurs. The collapse has been a central topic since the origin of the theory, although there are remarkable theoretical proposals to understand its nature, such as the Ghirardi–Rimini–Weber. Another possibility could be the assimilation of collapse with the now experimentally well established phenomenon of quantum jump, postulated by Bohr already in 1913. The challenge of nonlocality offers an opportunity to reconsider the quantum jump as a fundamental element of the logic of the physical world, rather than a subsidiary accident. We propose here a simple preliminary model that considers quantum jumps as processes of entry to and exit from the usual temporal domain to a timeless vacuum, without contradicting the quantum relativistic formalism, and we present some potential connections with particle physics. Quanta 2015; 4: 10–26.
Quantum jumps on Anderson attractors
Yusipov, I. I.; Laptyeva, T. V.; Ivanchenko, M. V.
2018-01-01
In a closed single-particle quantum system, spatial disorder induces Anderson localization of eigenstates and halts wave propagation. The phenomenon is vulnerable to interaction with environment and decoherence that is believed to restore normal diffusion. We demonstrate that for a class of experimentally feasible non-Hermitian dissipators, which admit signatures of localization in asymptotic states, quantum particle opts between diffusive and ballistic regimes, depending on the phase parameter of dissipators, with sticking about localization centers. In a diffusive regime, statistics of quantum jumps is non-Poissonian and has a power-law interval, a footprint of intermittent locking in Anderson modes. Ballistic propagation reflects dispersion of an ordered lattice and introduces the second timescale for jumps, resulting in non-nonmonotonous probability distribution. Hermitian dephasing dissipation makes localization features vanish, and Poissonian jump statistics along with normal diffusion are recovered.
International Nuclear Information System (INIS)
Carmichael, H.J.
2015-01-01
This paper cannot provide anything like a complete overview of quantum optics in New Zealand. The scope over 40 years is far too broad and the number of players far too large. Nevertheless, the story of quantum jumps, from the days of the Old Quantum Theory up to the present, serves to highlight some small part of the New Zealand experience. It also offers an encounter with the oddities of light as a quantum mechanical 'something', oddities that the gallant proposers of technologies for the future aim to exploit. (author).
Jump probabilities in the non-Markovian quantum jump method
International Nuclear Information System (INIS)
Haerkoenen, Kari
2010-01-01
The dynamics of a non-Markovian open quantum system described by a general time-local master equation is studied. The propagation of the density operator is constructed in terms of two processes: (i) deterministic evolution and (ii) evolution of a probability density functional in the projective Hilbert space. The analysis provides a derivation for the jump probabilities used in the recently developed non-Markovian quantum jump (NMQJ) method (Piilo et al 2008 Phys. Rev. Lett. 100 180402).
Quantum jumps are more quantum than quantum diffusion
International Nuclear Information System (INIS)
Daryanoosh, Shakib; M Wiseman, Howard
2014-01-01
It was recently argued (Wiseman and Gambetta 2012 Phys. Rev. Lett. 108 220402) that the stochastic dynamics (jumps or diffusion) of an open quantum system are not inherent to the system, but rather depend on the existence and nature of a distant detector. The proposed experimental tests involved homodyne detection, giving rise to quantum diffusion, and required efficiencies η of well over 50%. Here we prove that this requirement (η>0.5) is universal for diffusive-type detection, even if the system is coupled to multiple baths. However, this no-go theorem does not apply to quantum jumps, and we propose a test involving a qubit with jump-type detectors, with a threshold efficiency of only 37%. That is, quantum jumps are ‘more quantum’, and open the way to practical experimental tests. Our scheme involves a novel sort of adaptive monitoring scheme on a system coupled to two baths. (paper)
Tests for nonrandomness in quantum jumps
International Nuclear Information System (INIS)
Berkeland, D.J.; Raymondson, D.A.; Tassin, V.M.
2004-01-01
In a fundamental test of quantum mechanics, we have observed 228 000 quantum jumps of a single trapped and laser cooled 88 Sr + ion. This represents a statistical increase of two orders of magnitude over previous similar analyses of quantum jumps. Compared to other searches for nonrandomness in quantum-mechanical processes, using quantum jumps simplifies the interpretation of data by eliminated multiparticle effects and providing near-unit detection efficiency of transitions. We measure the fractional reduction in the entropy of information to be -4 when the value of any interval between quantum jumps is known. We also find that the number of runs of successively increasing or decreasing interval times agrees with the theoretically expected values. Furthermore, we analyze 238 000 quantum jumps from two simultaneously confined ions and find that the number of apparently coincidental transitions is as expected. Finally, we observe 8400 spontaneous decays of two simultaneously trapped ions and find that the number of apparently coincidental decays from the metastable state agrees with the expected value. We find no evidence for short- or long-term correlations in the intervals of the quantum jumps or in the decay of the quantum states, in agreement with quantum theory
International Nuclear Information System (INIS)
Schulman, L.S.
1997-01-01
Although the only time scale one ordinarily associates with a quantum transition is its lifetime, observations of ''quantum jumps'' in recent years show that the actual transition time is much shorter. I define a ''jump time'' as the time scale such that perturbations occurring at intervals of this duration affect the decay. In terms of the ''Zeno time'' (related to the second moment of the Hamiltonian) the jump time is τ J is identical to τ 2 Z /τ L . Corroboration is given. I also show that observing the ''jumping'' will not seriously affect the system lifetime, but will affect the linewidth. This is consistent with Bohr's ideas on measurement as well as with a heuristic time-energy uncertainty principle. (author)
Detected-jump-error-correcting quantum codes, quantum error designs, and quantum computation
International Nuclear Information System (INIS)
Alber, G.; Mussinger, M.; Beth, Th.; Charnes, Ch.; Delgado, A.; Grassl, M.
2003-01-01
The recently introduced detected-jump-correcting quantum codes are capable of stabilizing qubit systems against spontaneous decay processes arising from couplings to statistically independent reservoirs. These embedded quantum codes exploit classical information about which qubit has emitted spontaneously and correspond to an active error-correcting code embedded in a passive error-correcting code. The construction of a family of one-detected-jump-error-correcting quantum codes is shown and the optimal redundancy, encoding, and recovery as well as general properties of detected-jump-error-correcting quantum codes are discussed. By the use of design theory, multiple-jump-error-correcting quantum codes can be constructed. The performance of one-jump-error-correcting quantum codes under nonideal conditions is studied numerically by simulating a quantum memory and Grover's algorithm
The beginning of time observed in quantum jumps
Energy Technology Data Exchange (ETDEWEB)
Bohm, Arno [CCQS, Physics Department, University of Texas, Austin, TX (United States); Bryant, Peter W. [IBM Research, Rio de Janeiro (Brazil); Uncu, Haydar [Department of Physics, Adnan Menderes University, Aydin (Turkey); Wickramasekara, Sujeev [Department of Physics, Grinnell College, Grinnell, IA (United States); Schleich, Wolfgang P. [Institut fuer Quantenphysik and Center for Integrated Quantum Science and Technology, Universitaet Ulm (Germany); Hagler Institute for Advanced Study, Texas A and M University, College Station, TX (United States); Texas A and M AgriLife, Institute for Quantum Science and Engineering (IQSE) and Department of Physics and Astronomy, Texas A and M University, College Station, TX (United States)
2017-06-15
The phenomenon of quantum jumps observed in a single ion stored in a trap brings to light intimate connections between three different concepts of quantum physics: (i) quantum state trajectories, (ii) Gamow states, and (iii) the arrow of time. In particular, it allows us to identify the starting time of the semigroup time evolution. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Sub-Poissonian statistics of quantum jumps in single molecule or atomic ion
International Nuclear Information System (INIS)
Osad'ko, I.S.; Gus'kov, D.N.
2007-01-01
A theory for statistics of quantum jumps in single molecule or ion driven by continues wave laser field is developed. These quantum jumps can relate to nonradiative singlet-triplet transitions in a molecule or to on → off jumps in a single ion with shelving processes. Distribution function w N (T) of quantum jumps in time interval T is found. Computer simulation of quantum jumps is realized. Statistical treatment of simulated jumps reveals sub-Poissonian statistics of quantum jumps. The theoretical distribution function w N (T) fits well the distribution of jumps found from simulated data. Experimental data on quantum jumps found in experiments with single Hg + ion are described by the function w N (T) well
International Nuclear Information System (INIS)
Harbola, U.; Mukamel, S.
2008-01-01
Nonequilibrium Green's functions provide a powerful tool for computing the dynamical response and particle exchange statistics of coupled quantum systems. We formulate the theory in terms of the density matrix in Liouville space and introduce superoperator algebra that greatly simplifies the derivation and the physical interpretation of all quantities. Expressions for various observables are derived directly in real time in terms of superoperator nonequilibrium Green's functions (SNGF), rather than the artificial time-loop required in Schwinger's Hilbert-space formulation. Applications for computing interaction energies, charge densities, average currents, current induced fluorescence, electroluminescence and current fluctuation (electron counting) statistics are discussed
Projected evolution superoperators and the density operator
International Nuclear Information System (INIS)
Turner, R.E.; Dahler, J.S.; Snider, R.F.
1982-01-01
The projection operator method of Zwanzig and Feshbach is used to construct the time dependent density operator associated with a binary scattering event. The formula developed to describe this time dependence involves time-ordered cosine and sine projected evolution (memory) superoperators. Both Schroedinger and interaction picture results are presented. The former is used to demonstrate the equivalence of the time dependent solution of the von Neumann equation and the more familiar frequency dependent Laplace transform solution. For two particular classes of projection superoperators projected density operators are shown to be equivalent to projected wave functions. Except for these two special cases, no projected wave function analogs of projected density operators exist. Along with the decoupled-motions approximation, projected interaction picture density operators are applied to inelastic scattering events. Simple illustrations are provided of how this formalism is related to previously established results for two-state processes, namely, the theory of resonant transfer events, the first order Magnus approximation, and the Landau-Zener theory
Quantum computing with incoherent resources and quantum jumps.
Santos, M F; Cunha, M Terra; Chaves, R; Carvalho, A R R
2012-04-27
Spontaneous emission and the inelastic scattering of photons are two natural processes usually associated with decoherence and the reduction in the capacity to process quantum information. Here we show that, when suitably detected, these photons are sufficient to build all the fundamental blocks needed to perform quantum computation in the emitting qubits while protecting them from deleterious dissipative effects. We exemplify this by showing how to efficiently prepare graph states for the implementation of measurement-based quantum computation.
Zurek, Wojciech Hubert
2018-07-13
The emergence of the classical world from the quantum substrate of our Universe is a long-standing conundrum. In this paper, I describe three insights into the transition from quantum to classical that are based on the recognition of the role of the environment. I begin with the derivation of preferred sets of states that help to define what exists-our everyday classical reality. They emerge as a result of the breaking of the unitary symmetry of the Hilbert space which happens when the unitarity of quantum evolutions encounters nonlinearities inherent in the process of amplification-of replicating information. This derivation is accomplished without the usual tools of decoherence, and accounts for the appearance of quantum jumps and the emergence of preferred pointer states consistent with those obtained via environment-induced superselection, or einselection The pointer states obtained in this way determine what can happen-define events-without appealing to Born's Rule for probabilities. Therefore, p k =| ψ k | 2 can now be deduced from the entanglement-assisted invariance, or envariance -a symmetry of entangled quantum states. With probabilities at hand, one also gains new insights into the foundations of quantum statistical physics. Moreover, one can now analyse the information flows responsible for decoherence. These information flows explain how the perception of objective classical reality arises from the quantum substrate: the effective amplification that they represent accounts for the objective existence of the einselected states of macroscopic quantum systems through the redundancy of pointer state records in their environment-through quantum Darwinism This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).
Quantum Darwinism, Decoherence, and the Randomness of Quantum Jumps
Energy Technology Data Exchange (ETDEWEB)
Zurek, Wojciech H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-06-05
Tracing flows of information in our quantum Universe explains why we see the world as classical. Quantum principle of superposition decrees every combination of quantum states a legal quantum state. This is at odds with our experience. Decoherence selects preferred pointer states that survive interaction with the environment. They are localized and effectively classical. They persist while their superpositions decohere. Here we consider emergence of `the classical' starting at a more fundamental pre-decoherence level, tracing the origin of preferred pointer states and deducing their probabilities from the core quantum postulates. We also explore role of the environment as medium through which observers acquire information. This mode of information transfer leads to perception of objective classical reality.
Quantum jumps in a three-level system
International Nuclear Information System (INIS)
Javanainen, J.
1986-01-01
The authors study fluorescence in a scheme which is easy to treat theoretically: a two-level system driven by a laser and a third metastable state such that slow spontaneous transitions take place both from the excited state of a two-level system to the metastable state and from the metastable state to the ground state of the two-level system. With the aid of the quantum regression theorem the authors calculate the whole photon counting statistics at a detector which records scattering of the laser photons. In the limit of high intensity of the laser, the statistics of photon counts is found to be the same as the statistics of a two-state Markov jumps process. Thus, if the sequence of photon counts can be interpreted as a realization of a stochastic process, in a single experimental run the fluorescence should abruptly turn on and off for random intervals of time. The result is the same as given by the quantum-jump argument
Quantum jump from singularity to outside of black hole
Energy Technology Data Exchange (ETDEWEB)
Dündar, Furkan Semih [Physics and Mathematics Departments, Sakarya University, 54050, Sakarya (Turkey); Hajian, Kamal [School of Physics, Institute for Research in Fundamental Sciences, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Department of Physics, Sharif University of Technology, P.O. Box 11365-8639, Tehran (Iran, Islamic Republic of)
2016-02-26
Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as a part of his spacetime, then the semi-classical evolution would be non-unitary as viewed by him. Specifically, a free-falling observer inside the black hole would have a Hilbert space with non-unitary evolution; a quantum jump for particles encountering the singularity to outside of the horizon as late Hawking radiations. The non-unitarity in the jump resembles the one in collapse of wave function, but preserves entanglements. Accordingly, we elaborate the first postulate of black hole complementarity: freely falling observers who pass through the event horizon would have non-unitary evolution, while it does not have physically measurable effects for them. Besides, no information would be lost in the singularity. Taking the modified picture into account, the firewall paradox can be resolved, respecting No Drama. A by-product of our modification is that roughly half of the entropy of the black hole is released close to the end of evaporation in the shape of very hot Hawking radiation.
Quantum jump from singularity to outside of black hole
International Nuclear Information System (INIS)
Dündar, Furkan Semih; Hajian, Kamal
2016-01-01
Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as a part of his spacetime, then the semi-classical evolution would be non-unitary as viewed by him. Specifically, a free-falling observer inside the black hole would have a Hilbert space with non-unitary evolution; a quantum jump for particles encountering the singularity to outside of the horizon as late Hawking radiations. The non-unitarity in the jump resembles the one in collapse of wave function, but preserves entanglements. Accordingly, we elaborate the first postulate of black hole complementarity: freely falling observers who pass through the event horizon would have non-unitary evolution, while it does not have physically measurable effects for them. Besides, no information would be lost in the singularity. Taking the modified picture into account, the firewall paradox can be resolved, respecting No Drama. A by-product of our modification is that roughly half of the entropy of the black hole is released close to the end of evaporation in the shape of very hot Hawking radiation.
Superoperators in the dual model with coloured quarks
International Nuclear Information System (INIS)
Manida, S.N.
1978-01-01
The derivation of the dual model with coloured quarks is considered. The model is represented as a superoperator generalization of the Bardakci-Halpern model. It is shown that the three-regeon vertex of the model appears to be more compact and transparent
Quantum-capacity-approaching codes for the detected-jump channel
International Nuclear Information System (INIS)
Grassl, Markus; Wei Zhaohui; Ji Zhengfeng; Zeng Bei
2010-01-01
The quantum-channel capacity gives the ultimate limit for the rate at which quantum data can be reliably transmitted through a noisy quantum channel. Degradable quantum channels are among the few channels whose quantum capacities are known. Given the quantum capacity of a degradable channel, it remains challenging to find a practical coding scheme which approaches capacity. Here we discuss code designs for the detected-jump channel, a degradable channel with practical relevance describing the physics of spontaneous decay of atoms with detected photon emission. We show that this channel can be used to simulate a binary classical channel with both erasures and bit flips. The capacity of the simulated classical channel gives a lower bound on the quantum capacity of the detected-jump channel. When the jump probability is small, it almost equals the quantum capacity. Hence using a classical capacity-approaching code for the simulated classical channel yields a quantum code which approaches the quantum capacity of the detected-jump channel.
International Nuclear Information System (INIS)
Erber, T.; Hammerling, P.; Hockney, G.; Porrati, M.; Putterman, S.; La Jolla Institute, La Jolla, California 92037; Department of Physics, University of California, Los Angeles, California 90024)
1989-01-01
When a single trapped 198 Hg + ion is illuminated by two lasers, each tuned to an approximate transition, the resulting fluorescence switches on and off in a series of pulses resembling a bistable telegraph. This intermittent fluorescence can also be obtained by optical pumping with a single laser. Quantum jumps between successive atomic levels may be traced directly with multiple-resonance fluorescence. Atomic transition rates and photon antibunching distributions can be inferred from the pulse statistics and compared with quantum theory. Stochastic tests also indicate that the quantum telegraphs are good random number generators. During periods when the fluorescence is switched off, the radiationless atomic currents that generate the telegraph signals can be adjusted by varying the laser illumination: if this coherent evolution of the wave functions is sustained over sufficiently long time intervals, novel interactive precision measurements, near the limits of the time-energy uncertainty relations, are possible. Copyright 1989 Academic Press, Inc
Non-Poissonian quantum jumps of a fluxonium qubit due to quasiparticle excitations.
Vool, U; Pop, I M; Sliwa, K; Abdo, B; Wang, C; Brecht, T; Gao, Y Y; Shankar, S; Hatridge, M; Catelani, G; Mirrahimi, M; Frunzio, L; Schoelkopf, R J; Glazman, L I; Devoret, M H
2014-12-12
As the energy relaxation time of superconducting qubits steadily improves, nonequilibrium quasiparticle excitations above the superconducting gap emerge as an increasingly relevant limit for qubit coherence. We measure fluctuations in the number of quasiparticle excitations by continuously monitoring the spontaneous quantum jumps between the states of a fluxonium qubit, in conditions where relaxation is dominated by quasiparticle loss. Resolution on the scale of a single quasiparticle is obtained by performing quantum nondemolition projective measurements within a time interval much shorter than T₁, using a quantum-limited amplifier (Josephson parametric converter). The quantum jump statistics switches between the expected Poisson distribution and a non-Poissonian one, indicating large relative fluctuations in the quasiparticle population, on time scales varying from seconds to hours. This dynamics can be modified controllably by injecting quasiparticles or by seeding quasiparticle-trapping vortices by cooling down in a magnetic field.
Resonant Pump-dump Quantum Control of Solvated Dye Molecules with Phase Jumps
Konar, Arkaprabha; Lozovoy, Vadim; Dantus, Marcos
2014-03-01
Quantum coherent control of two photon and multiphoton excitation processes in atomic and condensed phase systems employing phase jumps has been well studied and understood. Here we demonstrate coherent quantum control of a two photon resonant pump-dump process in a complex solvated dye molecule. Phase jump in the frequency domain via a pulse shaper is employed to coherently enhance the stimulated emission by an order of magnitude when compared to transform limited pulses. Red shifted stimulated emission from successive low energy Stokes shifted excited states leading to narrowband emission are observed upon scanning the pi step across the excitation spectrum. A binary search space routine was also employed to investigate the effects of other types of phase jumps on stimulated emission and to determine the optimum phase that maximizes the emission. Understanding the underlying mechanism of this kind of enhancement will guide us in designing pulse shapes for enhancing stimulated emission, which can be further applied in the field of imaging.
Analyzing quantum jumps of one and two atoms strongly coupled to an optical cavity
DEFF Research Database (Denmark)
Reick, Sebastian; Mølmer, Klaus; Alt, Wolfgang
2010-01-01
We induce quantum jumps between the hyperfine ground states of one and two cesium atoms, strongly coupled to the mode of a high-finesse optical resonator, and analyze the resulting random telegraph signals. We identify experimental parameters to deduce the atomic spin state nondestructively from ...
Jumping magneto-electric states of electrons in semiconductor multiple quantum wells
International Nuclear Information System (INIS)
Pfeffer, Pawel; Zawadzki, Wlodek
2011-01-01
Orbital and spin electron states in semiconductor multiple quantum wells in the presence of an external magnetic field transverse to the growth direction are considered. Rectangular wells of GaAs/GaAlAs and InAs/AlSb are taken as examples. It is shown that, in addition to magneto-electric states known from one-well systems, there appear magneto-electric states having a much stronger dependence of energies on a magnetic field and exhibiting an interesting anti-crossing behavior. The origin of these states is investigated and it is shown that the strong field dependence of the energies is related to an unusual 'jumping' behavior of their wavefunctions between quantum wells as the field increases. The ways of investigating the jumping states by means of interband magneto-luminescence transitions or intraband cyclotron-like transitions are considered and it is demonstrated that the jumping states can be observed. The spin g factors of electrons in the jumping states are calculated using the real values of the spin–orbit interaction and bands' nonparabolicity for the semiconductors in question. It is demonstrated that the jumping states offer a wide variety of the spin g factors
Hidden Markov Model of atomic quantum jump dynamics in an optically probed cavity
DEFF Research Database (Denmark)
Gammelmark, S.; Molmer, K.; Alt, W.
2014-01-01
We analyze the quantum jumps of an atom interacting with a cavity field. The strong atom- field interaction makes the cavity transmission depend on the time dependent atomic state, and we present a Hidden Markov Model description of the atomic state dynamics which is conditioned in a Bayesian...... manner on the detected signal. We suggest that small variations in the observed signal may be due to spatial motion of the atom within the cavity, and we represent the atomic system by a number of hidden states to account for both the small variations and the internal state jump dynamics. In our theory...
International Nuclear Information System (INIS)
Fischer, Ernst Peter
2010-01-01
Who doesn't know the quantum jumps, which politicians like to promise in their speeched? But what the quantum jump in physics precisely means know only very few people. For this brings no enormous progress, but is in an ironical way the smallest change, which an atom can perform. This and other misunderstandings discovers Professor Ernst Peter Fischer in his new book. With funny comparisons from daily life he leads even laymen via ''The Backstairs to the Quantum Jump'' to the most important physical results. For this he characterizes important physicists like Niels Bohr, Alber Einstein, or Max Planck, and enters not only their discoveries, but also their personalities behind the genius.
Organic molecule fluorescence as an experimental test-bed for quantum jumps in thermodynamics.
Browne, Cormac; Farrow, Tristan; Dahlsten, Oscar C O; Taylor, Robert A; Vlatko, Vedral
2017-08-01
We demonstrate with an experiment how molecules are a natural test bed for probing fundamental quantum thermodynamics. Single-molecule spectroscopy has undergone transformative change in the past decade with the advent of techniques permitting individual molecules to be distinguished and probed. We demonstrate that the quantum Jarzynski equality for heat is satisfied in this set-up by considering the time-resolved emission spectrum of organic molecules as arising from quantum jumps between states. This relates the heat dissipated into the environment to the free energy difference between the initial and final state. We demonstrate also how utilizing the quantum Jarzynski equality allows for the detection of energy shifts within a molecule, beyond the relative shift.
Dropout dynamics in pulsed quantum dot lasers due to mode jumping
Energy Technology Data Exchange (ETDEWEB)
Sokolovskii, G. S.; Dudelev, V. V.; Deryagin, A. G.; Novikov, I. I.; Maximov, M. V.; Ustinov, V. M.; Kuchinskii, V. I. [Ioffe Physical-Technical Institute, St. Petersburg (Russian Federation); Viktorov, E. A. [National Research University of Information Technologies, Mechanics and Optics, Saint Petersburg (Russian Federation); Optique Nonlinéaire Théorique, Campus Plaine CP 231, 1050 Bruxelles (Belgium); Applied Physics Research Group (APHY), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); Abusaa, M. [Applied Physics Research Group (APHY), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); Arab American University, Jenin, Palestine (Country Unknown); Danckaert, J. [Applied Physics Research Group (APHY), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); Kolykhalova, E. D. [St. Petersburg State Electrotechnical University “LETI,” St. Petersburg (Russian Federation); Soboleva, K. K. [St. Petersburg State Polytechnical University, St. Petersburg (Russian Federation); Zhukov, A. E. [Academic University, St. Petersburg (Russian Federation); Sibbett, W. [University of St. Andrews, St. Andrews (United Kingdom); Rafailov, E. U. [Aston Institute of Photonic Technologies, Aston University, Birmingham (United Kingdom); Erneux, T. [Optique Nonlinéaire Théorique, Campus Plaine CP 231, 1050 Bruxelles (Belgium)
2015-06-29
We examine the response of a pulse pumped quantum dot laser both experimentally and numerically. As the maximum of the pump pulse comes closer to the excited-state threshold, the output pulse shape becomes unstable and leads to dropouts. We conjecture that these instabilities result from an increase of the linewidth enhancement factor α as the pump parameter comes close to the excitated state threshold. In order to analyze the dynamical mechanism of the dropout, we consider two cases for which the laser exhibits either a jump to a different single mode or a jump to fast intensity oscillations. The origin of these two instabilities is clarified by a combined analytical and numerical bifurcation diagram of the steady state intensity modes.
Dropout dynamics in pulsed quantum dot lasers due to mode jumping
International Nuclear Information System (INIS)
Sokolovskii, G. S.; Dudelev, V. V.; Deryagin, A. G.; Novikov, I. I.; Maximov, M. V.; Ustinov, V. M.; Kuchinskii, V. I.; Viktorov, E. A.; Abusaa, M.; Danckaert, J.; Kolykhalova, E. D.; Soboleva, K. K.; Zhukov, A. E.; Sibbett, W.; Rafailov, E. U.; Erneux, T.
2015-01-01
We examine the response of a pulse pumped quantum dot laser both experimentally and numerically. As the maximum of the pump pulse comes closer to the excited-state threshold, the output pulse shape becomes unstable and leads to dropouts. We conjecture that these instabilities result from an increase of the linewidth enhancement factor α as the pump parameter comes close to the excitated state threshold. In order to analyze the dynamical mechanism of the dropout, we consider two cases for which the laser exhibits either a jump to a different single mode or a jump to fast intensity oscillations. The origin of these two instabilities is clarified by a combined analytical and numerical bifurcation diagram of the steady state intensity modes
DEFF Research Database (Denmark)
Sannino, Francesco
2013-01-01
paradigm the physical scale and henceforth also the massive spectrum of the theory jump at the lower boundary of the conformal window. In particular we propose that a theory can suddenly jump from a Quantum Chromodynamics type spectrum, at the lower boundary of the conformal window, to a conformal one...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....
Optimising stochastic trajectories in exact quantum jump approaches of interacting systems
International Nuclear Information System (INIS)
Lacroix, D.
2004-11-01
The standard methods used to substitute the quantum dynamics of two interacting systems by a quantum jump approach based on the Stochastic Schroedinger Equation (SSE) are described. It turns out that for a given situation, there exists an infinite number of SSE reformulation. This fact is used to propose general strategies to optimise the stochastic paths in order to reduce the statistical fluctuations. In this procedure, called the 'adaptative noise method', a specific SSE is obtained for which the noise depends explicitly on both the initial state and on the properties of the interaction Hamiltonian. It is also shown that this method can be further improved by the introduction of a mean-field dynamics. The different optimisation procedures are illustrated quantitatively in the case of interacting spins. A significant reduction of the statistical fluctuations is obtained. Consequently, a much smaller number of trajectories is needed to accurately reproduce the exact dynamics as compared to the standard SSE method. (author)
Henkel, Christof
2017-03-01
We present an agent behavior based microscopic model that induces jumps, spikes and high volatility phases in the price process of a traded asset. We transfer dynamics of thermally activated jumps of an unexcited/excited two state system discussed in the context of quantum mechanics to agent socio-economic behavior and provide microfoundations. After we link the endogenous agent behavior to price dynamics we establish the circumstances under which the dynamics converge to an Itô-diffusion price processes in the large market limit.
International Nuclear Information System (INIS)
Fischer, Ernst Peter
2015-01-01
It's madness, yet there is method. The physical phenomenon of the quantum jump has already brought some well-known physicists at the edge of dispair. Then nothing seems to be such illogical, undetermined, and unpredictable as the behaviour of the atoms that ultimatively form our world. The renowned historian of sciences Ernst Peter Fischer tells the fascinating story of quantum physics by means of poignant portraits of selected researchers like Max Planck, Werner Heisenberg, Richard P. Feynman, and ''Mr. Beam'' Anton Zeilinger. A great story of science a bout the smallest particles of the nature.
Memory for Light as a Quantum Process
International Nuclear Information System (INIS)
Lobino, M.; Kupchak, C.; Lvovsky, A. I.; Figueroa, E.
2009-01-01
We report complete characterization of an optical memory based on electromagnetically induced transparency. We recover the superoperator associated with the memory, under two different working conditions, by means of a quantum process tomography technique that involves storage of coherent states and their characterization upon retrieval. In this way, we can predict the quantum state retrieved from the memory for any input, for example, the squeezed vacuum or the Fock state. We employ the acquired superoperator to verify the nonclassicality benchmark for the storage of a Gaussian distributed set of coherent states.
Density operators in quantum mechanics
International Nuclear Information System (INIS)
Burzynski, A.
1979-01-01
A brief discussion and resume of density operator formalism in the way it occurs in modern physics (in quantum optics, quantum statistical physics, quantum theory of radiation) is presented. Particularly we emphasize the projection operator method, application of spectral theorems and superoperators formalism in operator Hilbert spaces (Hilbert-Schmidt type). The paper includes an appendix on direct sums and direct products of spaces and operators, and problems of reducibility for operator class by using the projection operators. (author)
International Nuclear Information System (INIS)
Grinberg, H.
1983-11-01
The projection operator method of Zwanzig and Feshbach is used to construct the time-dependent field operators in the interaction picture. The formula developed to describe the time dependence involves time-ordered cosine and sine projected evolution (memory) superoperators, from which a master equation for the interaction-picture single-particle Green's function in a Liouville space is derived. (author)
Energy Technology Data Exchange (ETDEWEB)
Fischer, Ernst Peter
2010-07-01
Who doesn't know the quantum jumps, which politicians like to promise in their speeched? But what the quantum jump in physics precisely means know only very few people. For this brings no enormous progress, but is in an ironical way the smallest change, which an atom can perform. This and other misunderstandings discovers Professor Ernst Peter Fischer in his new book. With funny comparisons from daily life he leads even laymen via ''The Backstairs to the Quantum Jump'' to the most important physical results. For this he characterizes important physicists like Niels Bohr, Alber Einstein, or Max Planck, and enters not only their discoveries, but also their personalities behind the genius.
Xie, Xufen; Yan, Jiawei; Liang, Jinghong; Li, Jijun; Zhang, Meng; Mao, Bingwei
2013-10-01
We present quantum conductance measurements of germanium by means of an electrochemical scanning tunneling microscope (STM) break junction based on a jump-to-contact mechanism. Germanium nanowires between a platinum/iridium tip and different substrates were constructed to measure the quantum conductance. By applying appropriate potentials to the substrate and the tip, the process of heterogeneous contact and homogeneous breakage was realized. Typical conductance traces exhibit steps at 0.025 and 0.05 G0. The conductance histogram indicates that the conductance of germanium nanowires is located between 0.02 and 0.15 G0 in the low-conductance region and is free from the influence of substrate materials. However, the distribution of conductance plateaus is too discrete to display distinct peaks in the conductance histogram of the high-conductance region. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International Nuclear Information System (INIS)
Bruzda, Wojciech; Cappellini, Valerio; Sommers, Hans-Juergen; Zyczkowski, Karol
2009-01-01
We define a natural ensemble of trace preserving, completely positive quantum maps and present algorithms to generate them at random. Spectral properties of the superoperator Φ associated with a given quantum map are investigated and a quantum analogue of the Frobenius-Perron theorem is proved. We derive a general formula for the density of eigenvalues of Φ and show the connection with the Ginibre ensemble of real non-symmetric random matrices. Numerical investigations of the spectral gap imply that a generic state of the system iterated several times by a fixed generic map converges exponentially to an invariant state
Perturbative approach to Markovian open quantum systems.
Li, Andy C Y; Petruccione, F; Koch, Jens
2014-05-08
The exact treatment of Markovian open quantum systems, when based on numerical diagonalization of the Liouville super-operator or averaging over quantum trajectories, is severely limited by Hilbert space size. Perturbation theory, standard in the investigation of closed quantum systems, has remained much less developed for open quantum systems where a direct application to the Lindblad master equation is desirable. We present such a perturbative treatment which will be useful for an analytical understanding of open quantum systems and for numerical calculation of system observables which would otherwise be impractical.
DEFF Research Database (Denmark)
Lund, Ole; Ravn, Susanne; Christensen, Mette Krogh
2014-01-01
, in order to reach a deeper understanding of how practice facilitates learning. Results: We encircle the athletes’ interrelated learning processes by introducing the training environment of the national team and situations in which the athletes guide each other verbally or by jumping together. Discussion...
Muller, Andreas
2013-01-01
On October 14,2012, Felix Baumgartner, an Austrian sky-diver, set some new world records for his discipline. Jumping from a height of about 39 km, he reached a top speed of 1342 km/h, becoming the first human being to break the sound barrier in free fall. In order to understand some essential physics aspects of this remarkable feat, we wonder why…
Energy Technology Data Exchange (ETDEWEB)
Fischer, Ernst Peter
2015-07-01
It's madness, yet there is method. The physical phenomenon of the quantum jump has already brought some well-known physicists at the edge of dispair. Then nothing seems to be such illogical, undetermined, and unpredictable as the behaviour of the atoms that ultimatively form our world. The renowned historian of sciences Ernst Peter Fischer tells the fascinating story of quantum physics by means of poignant portraits of selected researchers like Max Planck, Werner Heisenberg, Richard P. Feynman, and ''Mr. Beam'' Anton Zeilinger. A great story of science a bout the smallest particles of the nature.
Energy Technology Data Exchange (ETDEWEB)
Feng, Liefeng, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Li, Yang [Business and Vocational College of Hainan, Haikou 570203 (China); Li, Ding; Hu, Xiaodong [Research Center for Wide Band Gap Semiconductors, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Li, Hongru, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn [State Key Laboratory for Medicinal Chemistry and Biology, College of Pharmacy, Nankai University, Tianjin 300071 (China)
2015-04-15
The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u} is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.
International Nuclear Information System (INIS)
Feng, Liefeng; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng; Li, Yang; Li, Ding; Hu, Xiaodong; Li, Hongru
2015-01-01
The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I th l and I th u , as shown in Fig. 2; I th l is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I th u is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V j ) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I th l and I th u . The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region
Coordination in vertical jumping
Bobbert, Maarten F.; van Ingen Schenau, Gerrit Jan
1988-01-01
The present study was designed to investigate for vertical jumping the relationships between muscle actions, movement pattern and jumping achievement. Ten skilled jumpers performed jumps with preparatory countermovement. Ground reaction forces and cinematographic data were recorded. In addition,
Lorenzetti, Silvio; Ammann, Fabian; Windmüller, Sabrina; Häberle, Ramona; Müller, Sören; Gross, Micah; Plüss, Michael; Plüss, Stefan; Schödler, Berni; Hübner, Klaus
2017-11-22
As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force-time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training.
Risk, Jumps, and Diversification
DEFF Research Database (Denmark)
Bollerslev, Tim; Law, Tzuo Hann; Tauchen, George
We test for price discontinuities, or jumps, in a panel of high-frequency intraday returns for forty large-cap stocks and an equiweighted index from these same stocks. Jumps are naturally classified into two types: common and idiosyncratic. Common jumps affect all stocks, albeit to varying degrees......, while idiosyncratic jumps are stock-specific. Despite the fact that each of the stocks has a of about unity with respect to the index, common jumps are virtually never detected in the individual stocks. This is truly puzzling, as an index can jump only if one or more of its components jump. To resolve...... this puzzle, we propose a new test for cojumps. Using this new test we find strong evidence for many modest-sized common jumps that simply pass through the standard jump detection statistic, while they appear highly significant in the cross section based on the new cojump identification scheme. Our results...
Visser, Albert
In this paper we study a new relation between sentences: the jump relation. The idea of the jump relation is based on an analysis of Feferman's Theorem that the inconsistency of a theory U is interpretable over U. The jump relation is based on a converse of Feferman's Theorem: if a sentence is
Visser, Albert
2014-01-01
In this paper we study a new relation between sentences: the jump relation. The idea of the jump relation is based on an analysis of Feferman's Theorem that the inconsistency of a theory U is interpretable over U. The jump relation is based on a converse of Feferman's Theorem: if a sentence is
Quantum information processing
National Research Council Canada - National Science Library
Leuchs, Gerd; Beth, Thomas
2003-01-01
... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 SimulationofHamiltonians... References... 1 1 1 3 5 8 10 2 Quantum Information Processing and Error Correction with Jump Codes (G. Alber, M. Mussinger...
Quantum computer with mixed states and four-valued logic
International Nuclear Information System (INIS)
Tarasov, Vasily E.
2002-01-01
In this paper we discuss a model of quantum computer in which a state is an operator of density matrix and gates are general quantum operations, not necessarily unitary. A mixed state (operator of density matrix) of n two-level quantum systems is considered as an element of 4 n -dimensional operator Hilbert space (Liouville space). It allows us to use a quantum computer model with four-valued logic. The gates of this model are general superoperators which act on n-ququat state. Ququat is a quantum state in a four-dimensional (operator) Hilbert space. Unitary two-valued logic gates and quantum operations for an n-qubit open system are considered as four-valued logic gates acting on n-ququats. We discuss properties of quantum four-valued logic gates. In the paper we study universality for quantum four-valued logic gates. (author)
Kato expansion in quantum canonical perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Nikolaev, Andrey, E-mail: Andrey.Nikolaev@rdtex.ru [Institute of Computing for Physics and Technology, Protvino, Moscow Region, Russia and RDTeX LTD, Moscow (Russian Federation)
2016-06-15
This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson’s ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders.
Kato expansion in quantum canonical perturbation theory
International Nuclear Information System (INIS)
Nikolaev, Andrey
2016-01-01
This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson’s ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders.
Quantum-statistical kinetic equations
International Nuclear Information System (INIS)
Loss, D.; Schoeller, H.
1989-01-01
Considering a homogeneous normal quantum fluid consisting of identical interacting fermions or bosons, the authors derive an exact quantum-statistical generalized kinetic equation with a collision operator given as explicit cluster series where exchange effects are included through renormalized Liouville operators. This new result is obtained by applying a recently developed superoperator formalism (Liouville operators, cluster expansions, symmetrized projectors, P q -rule, etc.) to nonequilibrium systems described by a density operator ρ(t) which obeys the von Neumann equation. By means of this formalism a factorization theorem is proven (being essential for obtaining closed equations), and partial resummations (leading to renormalized quantities) are performed. As an illustrative application, the quantum-statistical versions (including exchange effects due to Fermi-Dirac or Bose-Einstein statistics) of the homogeneous Boltzmann (binary collisions) and Choh-Uhlenbeck (triple collisions) equations are derived
DEFF Research Database (Denmark)
Bollerslev, Tim; Todorov, Victor
We propose a new and flexible non-parametric framework for estimating the jump tails of Itô semimartingale processes. The approach is based on a relatively simple-to-implement set of estimating equations associated with the compensator for the jump measure, or its "intensity", that only utilizes...... the weak assumption of regular variation in the jump tails, along with in-fill asymptotic arguments for uniquely identifying the "large" jumps from the data. The estimation allows for very general dynamic dependencies in the jump tails, and does not restrict the continuous part of the process...... and the temporal variation in the stochastic volatility. On implementing the new estimation procedure with actual high-frequency data for the S&P 500 aggregate market portfolio, we find strong evidence for richer and more complex dynamic dependencies in the jump tails than hitherto entertained in the literature....
Drop jumping. I. The influence of jumping technique on the biomechanics of jumping
Bobbert, M F; Huijing, P A; van Ingen Schenau, G J
In the literature, drop jumping is advocated as an effective exercise for athletes who prepare themselves for explosive activities. When executing drop jumps, different jumping techniques can be used. In this study, the influence of jumping technique on the biomechanics of jumping is investigated.
Rebilas, Krzysztof
2013-01-01
Consider a skier who goes down a takeoff ramp, attains a speed "V", and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is [alpha]. What is the optimal angle [alpha] that makes the jump the longest possible for the fixed magnitude of the…
Kim, Ho-Young
2016-11-01
Water striders can jump on water as high as they can jump on land. Quick jumps allow them to avoid sudden dangers such as predators' attacks, and therefore understanding how they make such a dramatic motion for survival can shed light on the ultimate level of semi-aquatic motility achievable through evolution. However, the mechanism of their vertical jumping from a water surface has eluded hydrodynamic explanations so far. By observing movements of water strider legs and theoretically analyzing their dynamic interactions with deforming liquid-air interface, we have recently found that different species of jumping striders always tune their leg rotation speed with a force just below that required to break the water surface to reach the maximum take-off velocity. Here, we start with discussing the fundamental theories of dynamics of floating and sinking of small objects. The theories then enable us to analyze forces acting on a water strider while it presses down the water surface to fully exploit the capillary force. We further introduce a 68-milligram at-scale robotic insect capable of jumping on water without splash, strikingly similar to the real strider, by utilizing the water surface just as a trampoline.
Barker, Leland A; Harry, John R; Mercer, John A
2018-01-01
Barker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI). Twenty-six, Division-I, male, soccer players performed 3 maximum effort countermovement jumps (CMJs) on a dual-force platform system that measured 3-dimensional kinetic data. The trial producing peak jump height was used for analysis. Vertical GRF (Fz) variables were divided into unloading, eccentric, amortization, and concentric phases and correlated with jump height, RSI (RSI = jump height/jump time), and jump time (from start to takeoff). Significant correlations were observed between jump height and RSI, concentric kinetic energy, peak power, concentric work, and concentric displacement. Significant correlations were observed between RSI and jump time, peak power, unload Fz, eccentric work, eccentric rate of force development (RFD), amortization Fz, amortization time, second Fz peak, average concentric Fz, and concentric displacement. Significant correlations were observed between jump time and unload Fz, eccentric work, eccentric RFD, amortization Fz, amortization time, average concentric Fz, and concentric work. In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance.
Why is countermovement jump height greater than squat jump height?
Bobbert, Maarten F.; Gerritsen, Karin G M; Litjens, Maria C A; Van Soest, Arthur J.
1996-01-01
In the literature, it is well established that subjects are able to jump higher in a countermovement jump (CMJ) than in a squat jump (SJ). The purpose of this study was to estimate the relative contribution of the time available for force development and the storage and reutilization of elastic
Drop Jumping as a Training Method for Jumping Ability
Bobbert, Maarten F.
1990-01-01
Vertical jumping ability is of importance for good performance in sports such as basketball and volleyball. Coaches are in need of exercises that consume only little time and still help to improve their players’ jumping ability, without involving a high risk of injury. Drop jumping is assumed to
Ball, Stephen; Cohen, Ann; Meyer, Margaret
2012-01-01
Jump Into Action (JIA) is a school-based team-taught program to help fifth-grade students make healthy food choices and be more active. The JIA team (physical education teacher, classroom teacher, school nurse, and parent) work together to provide a supportive environment as students set goals to improve food choices and increase activity.…
Fitzgerald, Mike; Brand, Lance
2004-01-01
In this article, the authors present an egg bungee jumping activity. This activity introduces students to ways that engineers might apply calculations of failure to meet a challenge. Students are required to use common, everyday materials such as rubber bands, string, plastic bags, and eggs. They will apply technological problem solving, material…
Indian Academy of Sciences (India)
SARS – virus jumps species. Coronavirus reshuffles genes; Rotteir et al, Rotterdam showed the virus to jump from cats to mouse cells after single gene mutation ? Human disease due to virus jumping from wild or domestic animals; Present favourite animal - the cat; - edible or domestic.
Accuracy of Jump-Mat Systems for Measuring Jump Height.
Pueo, Basilio; Lipinska, Patrycja; Jiménez-Olmedo, José M; Zmijewski, Piotr; Hopkins, Will G
2017-08-01
Vertical-jump tests are commonly used to evaluate lower-limb power of athletes and nonathletes. Several types of equipment are available for this purpose. To compare the error of measurement of 2 jump-mat systems (Chronojump-Boscosystem and Globus Ergo Tester) with that of a motion-capture system as a criterion and to determine the modifying effect of foot length on jump height. Thirty-one young adult men alternated 4 countermovement jumps with 4 squat jumps. Mean jump height and standard deviations representing technical error of measurement arising from each device and variability arising from the subjects themselves were estimated with a novel mixed model and evaluated via standardization and magnitude-based inference. The jump-mat systems produced nearly identical measures of jump height (differences in means and in technical errors of measurement ≤1 mm). Countermovement and squat-jump height were both 13.6 cm higher with motion capture (90% confidence limits ±0.3 cm), but this very large difference was reduced to small unclear differences when adjusted to a foot length of zero. Variability in countermovement and squat-jump height arising from the subjects was small (1.1 and 1.5 cm, respectively, 90% confidence limits ±0.3 cm); technical error of motion capture was similar in magnitude (1.7 and 1.6 cm, ±0.3 and ±0.4 cm), and that of the jump mats was similar or smaller (1.2 and 0.3 cm, ±0.5 and ±0.9 cm). The jump-mat systems provide trustworthy measurements for monitoring changes in jump height. Foot length can explain the substantially higher jump height observed with motion capture.
Asymptotic evolution of quantum Markov chains
Energy Technology Data Exchange (ETDEWEB)
Novotny, Jaroslav [FNSPE, CTU in Prague, 115 19 Praha 1 - Stare Mesto (Czech Republic); Alber, Gernot [Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
2012-07-01
The iterated quantum operations, so called quantum Markov chains, play an important role in various branches of physics. They constitute basis for many discrete models capable to explore fundamental physical problems, such as the approach to thermal equilibrium, or the asymptotic dynamics of macroscopic physical systems far from thermal equilibrium. On the other hand, in the more applied area of quantum technology they also describe general characteristic properties of quantum networks or they can describe different quantum protocols in the presence of decoherence. A particularly, an interesting aspect of these quantum Markov chains is their asymptotic dynamics and its characteristic features. We demonstrate there is always a vector subspace (typically low-dimensional) of so-called attractors on which the resulting superoperator governing the iterative time evolution of quantum states can be diagonalized and in which the asymptotic quantum dynamics takes place. As the main result interesting algebraic relations are presented for this set of attractors which allow to specify their dual basis and to determine them in a convenient way. Based on this general theory we show some generalizations concerning the theory of fixed points or asymptotic evolution of random quantum operations.
Rebilas, Krzysztof
2013-02-01
Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is α. What is the optimal angle α that makes the jump the longest possible for the fixed magnitude of the velocity V? Of course, in practice, this is a very sophisticated problem; the skier's range depends on a variety of complex factors in addition to V and α. However, if we ignore these and assume the jumper is in free fall between the takeoff ramp and the landing point below, the problem becomes an exercise in kinematics that is suitable for introductory-level students. The solution is presented here.
Yang, Eunjin; Kim, Ho-Young
2015-11-01
Small aquatic arthropods, such as water striders and fishing spiders, are able to jump off water to a height several times their body length. Inspired by the unique biological motility on water, we study a simple model using a flexible hoop to provide fundamental understanding and a mimicking principle of small jumpers on water. Behavior of a hoop on water, which is coated with superhydrophobic particles and initially bent into an ellipse from an equilibrium circular shape, is visualized with a high speed camera upon launching it into air by releasing its initial elastic strain energy. We observe that jumping of our hoops is dominated by the dynamic pressure of water rather than surface tension, and thus it corresponds to the dynamic condition experienced by fishing spiders. We calculate the reaction forces provided by water adopting the unsteady Bernoulli equation as well as the momentum loss into liquid inertia and viscous friction. Our analysis allows us to predict the jumping efficiency of the hoop on water in comparison to that on ground, and to discuss the evolutionary pressure rendering fishing spiders select such dynamic behavior.
Directory of Open Access Journals (Sweden)
Oscar Castro-Orgaz
2015-04-01
Full Text Available The transition from subcritical to supercritical flow when the inflow Froude number Fo is close to unity appears in the form of steady state waves called undular hydraulic jump. The characterization of the undular hydraulic jump is complex due to the existence of a non-hydrostatic pressure distribution that invalidates the gradually-varied flow theory, and supercritical shock waves. The objective of this work is to present a mathematical model for the undular hydraulic jump obtained from an approximate integration of the Reynolds equations for turbulent flow assuming that the Reynolds number R is high. Simple analytical solutions are presented to reveal the physics of the theory, and a numerical model is used to integrate the complete equations. The limit of application of the theory is discussed using a wave breaking condition for the inception of a surface roller. The validity of the mathematical predictions is critically assessed using physical data, thereby revealing aspects on which more research is needed
Al-Khalili, Jim
2003-01-01
In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way, he examines the paradox of quantum mechanics--beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through two separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. Baffle yourself with the bizzareness of quantum tunneling, the equivalent of traveling partway up a hill, only to disappear then reappear traveling down the opposite side. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics.
BPS Jumping Loci are Automorphic
Kachru, Shamit; Tripathy, Arnav
2018-06-01
We show that BPS jumping loci-loci in the moduli space of string compactifications where the number of BPS states jumps in an upper semi-continuous manner—naturally appear as Fourier coefficients of (vector space-valued) automorphic forms. For the case of T 2 compactification, the jumping loci are governed by a modular form studied by Hirzebruch and Zagier, while the jumping loci in K3 compactification appear in a story developed by Oda and Kudla-Millson in arithmetic geometry. We also comment on some curious related automorphy in the physics of black hole attractors and flux vacua.
Exploring Lightning Jump Characteristics
Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.
2014-01-01
This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.
Quantum operations that cannot be implemented using a small mixed environment
International Nuclear Information System (INIS)
Zalka, Christof; Rieffel, Eleanor
2002-01-01
To implement any quantum operation (a.k.a. ''superoperator'' or ''CP map'') on a d-dimensional quantum system, it is enough to apply a suitable overall unitary transformation to the system and a d 2 -dimensional environment which is initialized in a fixed pure state. It has been suggested that a d-dimensional environment might be enough if we could initialize the environment in a mixed state of our choosing. In this note we show with elementary means that certain explicit quantum operations cannot be realized in this way. Our counterexamples map some pure states to pure states, giving strong and easily manageable conditions on the overall unitary transformation. Everything works in the more general setting of quantum operations from d-dimensional to d ' -dimensional spaces, so we place our counterexamples within this more general framework
Jump conditions in transonic equilibria
International Nuclear Information System (INIS)
Guazzotto, L.; Betti, R.; Jardin, S. C.
2013-01-01
In the present paper, the numerical calculation of transonic equilibria, first introduced with the FLOW code in Guazzotto et al.[Phys. Plasmas 11, 604 (2004)], is critically reviewed. In particular, the necessity and effect of imposing explicit jump conditions at the transonic discontinuity are investigated. It is found that “standard” (low-β, large aspect ratio) transonic equilibria satisfy the correct jump condition with very good approximation even if the jump condition is not explicitly imposed. On the other hand, it is also found that high-β, low aspect ratio equilibria require the correct jump condition to be explicitly imposed. Various numerical approaches are described to modify FLOW to include the jump condition. It is proved that the new methods converge to the correct solution even in extreme cases of very large β, while they agree with the results obtained with the old implementation of FLOW in lower-β equilibria.
Kim, Ho-Young; Amauger, Juliette; Jeong, Han-Bi; Lee, Duck-Gyu; Yang, Eunjin; Jablonski, Piotr G.
2017-10-01
Some species of semiaquatic arthropods including water striders and springtails can jump from the water surface to avoid sudden dangers like predator attacks. It was reported recently that the jump of medium-sized water striders is a result of surface-tension-dominated interaction of thin cylindrical legs and water, with the leg movement speed nearly optimized to achieve the maximum takeoff velocity. Here we describe the mathematical theories to analyze this exquisite feat of nature by combining the review of existing models for floating and jumping and the introduction of the hitherto neglected capillary forces at the cylinder tips. The theoretically predicted dependence of body height on time is shown to match the observations of the jumps of the water striders and springtails regardless of the length of locomotory appendages. The theoretical framework can be used to understand the design principle of small jumping animals living on water and to develop biomimetic locomotion technology in semiaquatic environments.
Thersites: a `jumping' Trojan?
Tsiganis, K.; Dvorak, R.; Pilat-Lohinger, E.
2000-02-01
In this paper, we examine the dynamical evolution of the asteroid (1868) Thersites, a member of the Trojan belt. Thersites is librating around the Lagrangian point L_4, following, however, a chaotic orbit. The equations of motion for Thersites as well as for a distribution of neighboring initial conditions are integrated numerically for 50 million years in the Outer Solar System model (OSS), which consists of the Sun and the four giant planets. Our results indicate that the probability that this asteroid will eventually escape from the Trojan swarm is rather high. In fact, 20% from our initial distribution escaped within the integration time. Many of the remaining ones also show characteristic `jumps' in the orbital elements, especially the inclination. Secular resonances involving the nodes of the outer planets are found to be responsible for this chaotic behavior. The width of libration and eccentricity values that lead to grossly unstable orbits are calculated and compared with previously known results on the stability of the Trojans. Finally, a very interesting behavior has been observed for one of the escaping asteroids as he `jumped' from L_4 to L_5 where he remained performing a highly inclined libration for ~ 2 Myrs before escaping from the Trojan swarm. According to Homer, Thersites was not only the ugliest of all Greeks that took part in the Trojan war, but also had the most intolerable personality. His nasty habit of making fun of everybody cost him his life, as the last person for whom he spoke ironically about was Achilles, the mightiest warrior of all Greeks, who killed Thersites with just one punch!
DEFF Research Database (Denmark)
Ravn, Susanne; Voigt, M; Simonsen, Erik Bruun
1999-01-01
. The jumps were recorded on highspeed film (500 Hz) combined with registration of ground reaction forces, and net joint moments were calculated by inverse dynamics. The purpose was to investigate the choice of strategy in two standard jumps, squat jump and countermovement jump. The volleyball jump...... was performed with a sequential strategy and the ballet jump was performed with a simultaneous strategy. In the two standard jumps, the choice of strategy was individual and not related to training background. This was additionally confirmed in a test of seven ballet dancers and seven volleyball players....
DEFF Research Database (Denmark)
Bonn, D.; Andersen, Anders Peter; Bohr, Tomas
2009-01-01
We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected......'s mixing-length theory with a mixing length that is proportional to the height of the fluid layer. Using averaged boundary-layer equations, taking into account the friction with the channel walls and the eddy viscosity, the flow both upstream and downstream of the jump can be understood. For the downstream...... subcritical flow, we assume that the critical height is attained close to the channel outlet. We use mass and momentum conservation to determine the position of the jump and obtain an estimate which is in rough agreement with our experiment. We show that the averaging method with a varying velocity profile...
Duchesne, Alexis; Bohr, Tomas; Andersen, Anders
2017-11-01
The hydraulic jump, i.e., the sharp transition between a supercritical and a subcritical free-surface flow, has been extensively studied in the past centuries. However, ever since Leonardo da Vinci asked it for the first time, an important question has been left unanswered: How does a hydraulic jump form? We present an experimental and theoretical study of the formation of stationary hydraulic jumps in centimeter wide channels. Two starting situations are considered: The channel is, respectively, empty or filled with liquid, the liquid level being fixed by the wetting properties and the boundary conditions. We then change the flow-rate abruptly from zero to a constant value. In an empty channel, we observe the formation of a stationary hydraulic jump in a two-stage process: First, the channel fills by the advancing liquid front, which undergoes a transition from supercritical to subcritical at some position in the channel. Later the influence of the downstream boundary conditions makes the jump move slowly upstream to its final position. In the pre-filled channel, the hydraulic jump forms at the injector edge and then moves downstream to its final position.
Variation in free jumping technique within and among horses with little experience in show jumping
Santamaria, S.; Bobbert, M.F.; Back, W.; Barneveld, A.; van Weeren, P.R.
2004-01-01
Objective - To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among
Non-reversible evolution of quantum chaotic system. Kinetic description
International Nuclear Information System (INIS)
Chotorlishvili, L.; Skrinnikov, V.
2008-01-01
It is well known that the appearance of non-reversibility in classical chaotic systems is connected with a local instability of phase trajectories relatively to a small change of initial conditions and parameters of the system. Classical chaotic systems reveal an exponential sensitivity to these changes. This leads to an exponential growth of initial error with time, and as the result after the statistical averaging over this error, the dynamics of the system becomes non-reversible. In spite of this, the question about the origin of non-reversibility in quantum case remains actual. The point is that the classical notion of instability of phase trajectories loses its sense during quantum consideration. The current work is dedicated to the clarification of the origin of non-reversibility in quantum chaotic systems. For this purpose we study a non-stationary dynamics of the chaotic quantum system. By analogy with classical chaos, we consider an influence of a small unavoidable error of the parameter of the system on the non-reversibility of the dynamics. It is shown in the Letter that due to the peculiarity of chaotic quantum systems, the statistical averaging over the small unavoidable error leads to the non-reversible transition from the pure state into the mixed one. The second part of the Letter is dedicated to the kinematic description of the chaotic quantum-mechanical system. Using the formalism of superoperators, a muster kinematic equation for chaotic quantum system was obtained from Liouville equation under a strict mathematical consideration
Scaling of interfacial jump conditions
International Nuclear Information System (INIS)
Quezada G, S.; Vazquez R, A.; Espinosa P, G.
2015-09-01
To model the behavior of a nuclear reactor accurately is needed to have balance models that take into account the different phenomena occurring in the reactor. These balances have to be coupled together through boundary conditions. The boundary conditions have been studied and different treatments have been given to the interface. In this paper is a brief description of some of the interfacial jump conditions that have been proposed in recent years. Also, the scaling of an interfacial jump condition is proposed, for coupling the different materials that are in contact within a nuclear reactor. (Author)
From the atomic nucleus to the cosmos. How the strange laws of the quantum world form our reality
International Nuclear Information System (INIS)
Beckers, Mike
2016-01-01
The following topics are dealt with: The reality of nature, Hamlet in quantum world, the ene of the local realism, quantum jumps, a new quantum theory, string theory for solids, atomic nuclei between liquid and crystal, simulated quantum worlds, space-time entanglement, Einstein in the quantum test, quantum cryptography, quantum computers as code breaker. (HSI)
Scaling of quantum Fisher information close to the quantum phase transition in the XY spin chain
Energy Technology Data Exchange (ETDEWEB)
Ye, En-Jia, E-mail: yeenjia@jiangnan.edu.cn [Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, School of Science, Jiangnan University, Wuxi 214122 (China); Hu, Zheng-Da [Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, School of Science, Jiangnan University, Wuxi 214122 (China); Wu, Wei [Zhejiang Institute of Modern Physics and Physics Department, Zhejiang University, Hangzhou 310027 (China)
2016-12-01
The quantum phase transition of an XY spin chain is investigated by employing the quantum Fisher information encoded in the ground state. It is shown that the quantum Fisher information is an effective tool for characterizing the quantum criticality. The quantum Fisher information, its first and second derivatives versus the transverse field display the phenomena of sudden transition, sudden jump and divergence, respectively. Besides, the analysis of finite size scaling for the second derivative of quantum Fisher information is performed.
Pressure Jumps during Drainage in Macroporous Soils
DEFF Research Database (Denmark)
Soto, Diego; Paradelo Pérez, Marcos; Corral, A
2018-01-01
Tensiometer readings obtained at high resolution during drainage of structured soil columns revealed pressure jumps with long range correlations and burst sequences with a hierarchical structure. The statistical properties of jumps are similar to Haines jumps described in invasion percolation...... processes at pore scale, but they are much larger in amplitude and duration. Pressure jumps can result from transient redistribution of water potential in internal regions of soil and can be triggered during drainage by capillary displacements at the scale of structural pores....
The identification of price jumps
Czech Academy of Sciences Publication Activity Database
Hanousek, Jan; Kočenda, Evžen; Novotný, Jan
2012-01-01
Roč. 18, č. 1 (2012), s. 53-77 ISSN 0929-9629 R&D Projects: GA ČR(CZ) GAP403/11/0020; GA ČR(CZ) GBP402/12/G097 Institutional support: PRVOUK-P23 Keywords : price jumps * non-parametric testing * financial econometrics Subject RIV: AH - Economics
Regime Jumps in Electricity Prices
R. Huisman (Ronald); R.J. Mahieu (Ronald)
2001-01-01
textabstractElectricity prices are known to be very volatile and subject to frequent jumps due to system breakdown, demand shocks, and inelastic supply. As many international electricity markets are in some state of deregulation, more and more participants in these markets are exposed to these
Mesopause Jumps: Observations and Explanation
Luebken, F. J.; Becker, E.; Höffner, J.; Viehl, T. P.; Latteck, R.
2017-12-01
Recent high resolution temperature measurements by resonance lidar at Davis (69°S) occasionally showed a sudden mesopause altitude increase by 5km and an associated mesopause temperature decrease by 10K. We present further observations which are closely related to this `mesopause jump', namely the increase of mean height of polar mesospheric summer echoes (PMSE) observed by a VHF radar, very strong westward winds in the upper mesosphere measured by an MF radar, and relatively large eastward winds in the stratosphere taken from reanalysis. We compare to similar observations in the Northern Hemisphere, namely at ALOMAR (69°N) where such mesopause jumps have never been observed. We present a detailed explanation of mesopause jumps. They occur only when stratospheric winds are moderately eastward and mesospheric winds are very large (westward). Under these conditions, gravity waves with comparatively large eastward phase speeds can pass the stratosphere and propagate to the lower thermosphere because their vertical wavelengths in the mesosphere are rather large which implies reduced dynamical stability. When finally breaking in the lower thermosphere, these waves drive an enhanced residual circulation that causes a cold and high-altitude mesopause. The conditions for a mesopause jump occur only in the Southern Hemisphere (SH) and are associated with the late breakdown of the polar vortex.Mesopause jumps are primarily, but not only, observed prior and close to solstice. We also show that during the onset of PMSE in the SH, stratospheric zonal winds are still eastward (up to 30m/s), and that the onset is not closely related to the transition of the stratospheric circulation.
Stephenson, Mitchell L; Hinshaw, Taylour J; Wadley, Haley A; Zhu, Qin; Wilson, Margaret A; Byra, Mark; Dai, Boyi
2018-03-01
A variety of the available time to react (ATR) has been utilised to study knee biomechanics during reactive jump-landing tasks. The purpose was to quantify knee kinematics and kinetics during a jump-land-jump task of three possible directions as the ATR was reduced. Thirty-four recreational athletes performed 45 trials of a jump-land-jump task, during which the direction of the second jump (lateral, medial or vertical) was indicated before they initiated the first jump, the instant they initiated the first jump, 300 ms before landing, 150 ms before landing or at the instant of landing. Knee joint angles and moments close to the instant of landing were significantly different when the ATR was equal to or more than 300 ms before landing, but became similar when the ATR was 150 ms or 0 ms before landing. As the ATR was decreased, knee moments decreased for the medial jump direction, but increased for the lateral jump direction. When the ATR is shorter than an individual's reaction time, the movement pattern cannot be pre-planned before landing. Knee biomechanics are dependent on the timing of the signal and the subsequent jump direction. Precise control of timing and screening athletes with low ATR are suggested.
Locomotion of Mexican jumping beans
International Nuclear Information System (INIS)
West, Daniel M; K Lal, Ishan; Leamy, Michael J; Hu, David L
2012-01-01
The Mexican jumping bean, Laspeyresia saltitans, consists of a hollow seed housing a moth larva. Heating by the sun induces movements by the larva which appear as rolls, jumps and flips by the bean. In this combined experimental, numerical and robotic study, we investigate this unique means of rolling locomotion. Time-lapse videography is used to record bean trajectories across a series of terrain types, including one-dimensional channels and planar surfaces of varying inclination. We find that the shell encumbers the larva's locomotion, decreasing its speed on flat surfaces by threefold. We also observe that the two-dimensional search algorithm of the bean resembles the run-and-tumble search of bacteria. We test this search algorithm using both an agent-based simulation and a wheeled Scribbler robot. The algorithm succeeds in propelling the robot away from regions of high temperature and may have application in biomimetic micro-scale navigation systems. (paper)
Model for polygonal hydraulic jumps
DEFF Research Database (Denmark)
Martens, Erik Andreas; Watanabe, Shinya; Bohr, Tomas
2012-01-01
We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers [Nature (London) 392, 767 (1998); Nonlinearity 12, 1 (1999); Physica B 228, 1 (1996)], based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy...... nonhydrostatic pressure contributions from surface tension in light of recent observations by Bush and co-workers [J. Fluid Mech. 558, 33 (2006); Phys. Fluids 16, S4 (2004)]. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal...... states. A truncated but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a polygon with N corners...
Data-Driven Jump Detection Thresholds for Application in Jump Regressions
Directory of Open Access Journals (Sweden)
Robert Davies
2018-03-01
Full Text Available This paper develops a method to select the threshold in threshold-based jump detection methods. The method is motivated by an analysis of threshold-based jump detection methods in the context of jump-diffusion models. We show that over the range of sampling frequencies a researcher is most likely to encounter that the usual in-fill asymptotics provide a poor guide for selecting the jump threshold. Because of this we develop a sample-based method. Our method estimates the number of jumps over a grid of thresholds and selects the optimal threshold at what we term the ‘take-off’ point in the estimated number of jumps. We show that this method consistently estimates the jumps and their indices as the sampling interval goes to zero. In several Monte Carlo studies we evaluate the performance of our method based on its ability to accurately locate jumps and its ability to distinguish between true jumps and large diffusive moves. In one of these Monte Carlo studies we evaluate the performance of our method in a jump regression context. Finally, we apply our method in two empirical studies. In one we estimate the number of jumps and report the jump threshold our method selects for three commonly used market indices. In the other empirical application we perform a series of jump regressions using our method to select the jump threshold.
Psychophysiological response in parachute jumps, the effect of experience and type of jump.
Clemente-Suárez, Vicente Javier; Robles-Pérez, José Juan; Fernández-Lucas, Jesús
2017-10-01
We aimed to analyse the effect of experience and type of parachute jump on the psychophysiological responses of jumpers. We analysed blood oxygen saturation, heart rate, blood glucose, lactate and creatinkinase, leg strength, isometric hand strength, cortical arousal, specific fine motor skills, self-confidence and cognition, and somatic and state anxiety, before and after four different parachute jumps: a sport parachute jump, a manual tactical parachute jump, tandem pilots, and tandem passengers. Independently of the parachute jump, the psychophysiological responses of experienced paratroopers were not affected by the jumps, except for an increase in anaerobic metabolism. Novice parachute jumpers presented a higher psychophysiological stress response than the experienced jumpers, together with a large anticipatory anxiety response before the jump; however, this decreased after the jump, although the high physiological activation was maintained. This information could be used by civil and military paratroopers' instructors to improve their training programmes. Copyright © 2017 Elsevier Inc. All rights reserved.
Dynamic jump intensities and risk premiums
DEFF Research Database (Denmark)
Christoffersen, Peter; Ornthanalai, Chayawat; Jacobs, Kris
2012-01-01
We build a new class of discrete-time models that are relatively easy to estimate using returns and/or options. The distribution of returns is driven by two factors: dynamic volatility and dynamic jump intensity. Each factor has its own risk premium. The models significantly outperform standard...... models without jumps when estimated on S&P500 returns. We find very strong support for time-varying jump intensities. Compared to the risk premium on dynamic volatility, the risk premium on the dynamic jump intensity has a much larger impact on option prices. We confirm these findings using joint...
Characteristics of Air Entrainment in Hydraulic Jump
Albarkani, M. S. S.; Tan, L. W.; Al-Gheethi, A.
2018-04-01
The characteristics of hydraulic jump, especially the air entrainment within jump is still not properly understood. Therefore, the current work aimed to determine the size and number of air entrainment formed in hydraulic jump at three different Froude numbers and to obtain the relationship between Froude number with the size and number of air entrainment in hydraulic jump. Experiments of hydraulic jump were conducted in a 10 m long and 0.3 m wide Armfield S6MKII glass-sided tilting flume. Hydraulic jumps were produced by flow under sluice gate with varying Froude number. The air entrainment of the hydraulic jump was captured with a Canon Power Shot SX40 HS digital camera in video format at 24 frames per second. Three discharges have been considered, i.e. 0.010 m3/s, 0.011 m3/s, and 0.013 m3/s. For hydraulic jump formed in each discharge, 32 frames were selected for the purpose of analysing the size and number of air entrainment in hydraulic jump. The results revealed that that there is a tendency to have greater range in sizes of air bubbles as Fr1 increases. Experiments with Fr1 = 7.547. 7.707, and 7.924 shown that the number of air bubbles increases exponentially with Fr1 at a relationship of N = 1.3814 e 0.9795Fr1.
Improved safety in ski jumping.
Wester, K
1988-01-01
Among approximately 2,600 licensed Norwegian ski jumpers, only three injuries that caused a permanent medical disability of at least 10% were incurred during the 5 year period from 1982 through 1986. When compared to the previous 5 year period (1977 to 1981), a dramatic improvement in safety is seen, as both number and severity of such injuries were markedly reduced. There are several probable reasons for this improved safety record: better preparation of the jumps, the return to using only one standard heel block, and the fact that coaches are being more responsible, especially with younger jumpers.
Kinematics and Kinetics of Squats, Drop Jumps and Imitation Jumps of Ski Jumpers.
Pauli, Carole A; Keller, Melanie; Ammann, Fabian; Hübner, Klaus; Lindorfer, Julia; Taylor, William R; Lorenzetti, Silvio
2016-03-01
Squats, drop jumps, and imitation jumps are commonly used training exercises in ski jumping to enhance maximum force, explosive force, and sport-specific skills. The purpose of this study was to evaluate the kinetics and kinematics of training exercises in ski jumping and to find objective parameters in training exercises that most correlate with the competition performance of ski jumpers. To this end, barbell squats, drop jumps, and imitation jumps were measured in a laboratory environment for 10 elite ski jumpers. Force and motion data were captured, and the influence of maximum vertical force, force difference, vertical take-off velocity, knee moments, knee joint power, and a knee valgus/varus index was evaluated and correlated with their season jump performance. The results indicate that, especially for the imitation jumps, a good correlation exists between the vertical take-off velocity and the personal jump performance on the hill (R = 0.718). Importantly, however, the more the athletes tended toward a valgus knee alignment during the measured movements, the worse their performance (R = 0.729 imitation jumps; R = 0.685 squats). Although an evaluation of the athletes' lower limb alignment during competitive jumping on the hill is still required, these preliminary data suggest that performance training should additionally concentrate on improving knee alignment to increase ski jumping performance.
Chaos, entropy, and life-time in classical and quantum systems
International Nuclear Information System (INIS)
Seyed Majid Saberi Fathi
2007-07-01
In this thesis, we first study Lorentz gas as a billiard ball with elastic collision with the obstacles and a system of hard spheres in 2-dimensions. We study a numerical simulation of the dynamical system and we investigate the entropy increasing in non-equilibrium with time under the effect of collisions and its relation to positive Lyapunov exponents. Then, we study a decay model in a quantum system called Friedrichs model. We consider coupling of the kaons and environment with continuous energies. Then, we show that this model is well adapted to describe oscillation, regeneration, decay and CP violation of a kaonic system. In addition, we apply in the Friedrichs model, the time super-operator formalism that predicts the resonance, i.e. the survival probability of the instable states. (author)
Separation and pattern formation in hydraulic jumps
DEFF Research Database (Denmark)
Bohr, Tomas; Ellegaard, C.; Hansen, A. Espe
1998-01-01
We present theory and experiments on the circular hydraulic jump in the stationary regime. The theory can handle the situation in which the fluid flows over an edge far away from the jump. In the experiments the external height is controlled, and a series of transitions in the flow structure appe...
Biomechanical analysis of drop and countermovement jumps
Bobbert, M. F.; Mackay, M.T.; Schinkelshoek, D.; Huijing, P. A.; van Ingen Schenau, G. J.
For 13 subjects the performance of drop jumps from a height of 40 cm (DJ) and of countermovement jumps (CMJ) was analysed and compared. From force plate and cine data biomechanical variables including forces, moments, power output and amount of work done were calculated for hip, knee and ankle
Jump Detection in the Danish Stock Market
DEFF Research Database (Denmark)
Høg, Esben
2002-01-01
It is well known in financial economics that stock market return data are often modelled by a diffusion process with some regular drift function. Occasionally, however, sudden changes or jumps occur in the return data. Wavelet scaling methods are used to detect jumps and cusps in stock market...
DEFF Research Database (Denmark)
Fasterhold, Martin; Pichlmair, Martin; Holmgård, Christoffer
This paper explores the design of jumping in 2D platform games. Through creating a method for measuring existing games, applying this method to a selection of different platformer games, and analysing the results, the paper arrives at a comprehensive data model for jumping. The model supports the...
Usefulness of the jump-and-reach test in assessment of vertical jump performance.
Menzel, Hans-Joachim; Chagas, Mauro H; Szmuchrowski, Leszek A; Araujo, Silvia R; Campos, Carlos E; Giannetti, Marcus R
2010-02-01
The objective was to estimate the reliability and criterion-related validity of the Jump-and-Reach Test for the assessment of squat, countermovement, and drop jump performance of 32 male Brazilian professional volleyball players. Performance of squat, countermovement, and drop jumps with different dropping heights was assessed on the Jump-and-Reach Test and the measurement of flight time, then compared across different jump trials. The very high reliability coefficients of both assessment methods and the lower correlation coefficients between scores on the assessments indicate a very high consistency of each method but only moderate covariation, which means that they measure partly different items. As a consequence, the Jump-and-Reach Test has good ecological validity in situations when reaching height during the flight phase is critical for performance (e.g., basketball and volleyball) but only limited accuracy for the assessment of vertical impulse production with different jump techniques and conditions.
A review on the basketball jump shot.
Okazaki, Victor H A; Rodacki, André L F; Satern, Miriam N
2015-06-01
The ability to shoot an effective jump shot in the sport of basketball is critical to a player's success. In an attempt to better understand the aspects related to expert performance, researchers have investigated successful free throws and jump shots of various basketball players and identified movement variables that contribute to their success. The purpose of this study was to complete a systematic review of the scientific literature on the basketball free throw and jump shot for the purpose of revealing the critical components of shooting that coaches, teachers, and players should focus on when teaching, learning, practising, and performing a jump shot. The results of this review are presented in three sections: (a) variables that affect ball trajectory, (b) phases of the jump shot, and (c) additional variables that influence shooting.
International Nuclear Information System (INIS)
Labuntsov, D.A.; Avdeev, A.A.
1981-01-01
Concept of boiling-up jump representing a zone of intense volume boiling-up separating overtaking flow of overheated metastable liquid from an area of equilibrium flow located below along the flow is introduced. It is shown that boiling-up jump is a shock wave of rarefaction. It is concluded that entropy increment occurs on the jump. Characteristics of adiabatic shock wave curve of boiling- up in ''pressure-specific volume'' coordinates have been found and its form has been investigated. Stability of boiling-up jump has been analyzed as well. On the basis of approach developed analysis is carried out on the shock adiobatic curve of condensation. Concept of boiling-up jump may be applied to the analysis of boiling-up processes when flowing liquid through packings during emergency pressure drop etc [ru
Kinematics and Kinetics of Squats, Drop Jumps and Imitation Jumps of Ski Jumpers
Pauli, Carole A.; Keller, Melanie; Ammann, Fabian; Hübner, Klaus; Lindorfer, Julia; Taylor, William R.
2016-01-01
Abstract Pauli, CA, Keller, M, Ammann, F, Hübner, K, Lindorfer, J, Taylor, WR, and Lorenzetti, S. Kinematics and kinetics of squats, drop jumps and imitation jumps of ski jumpers. J Strength Cond Res 30(3): 643–652, 2016—Squats, drop jumps, and imitation jumps are commonly used training exercises in ski jumping to enhance maximum force, explosive force, and sport-specific skills. The purpose of this study was to evaluate the kinetics and kinematics of training exercises in ski jumping and to find objective parameters in training exercises that most correlate with the competition performance of ski jumpers. To this end, barbell squats, drop jumps, and imitation jumps were measured in a laboratory environment for 10 elite ski jumpers. Force and motion data were captured, and the influence of maximum vertical force, force difference, vertical take-off velocity, knee moments, knee joint power, and a knee valgus/varus index was evaluated and correlated with their season jump performance. The results indicate that, especially for the imitation jumps, a good correlation exists between the vertical take-off velocity and the personal jump performance on the hill (R = 0.718). Importantly, however, the more the athletes tended toward a valgus knee alignment during the measured movements, the worse their performance (R = 0.729 imitation jumps; R = 0.685 squats). Although an evaluation of the athletes' lower limb alignment during competitive jumping on the hill is still required, these preliminary data suggest that performance training should additionally concentrate on improving knee alignment to increase ski jumping performance. PMID:26418370
Mobile Jump Assessment (mJump): A Descriptive and Inferential Study.
Mateos-Angulo, Alvaro; Galán-Mercant, Alejandro; Cuesta-Vargas, Antonio
2015-08-26
Vertical jump tests are used in athletics and rehabilitation to measure physical performance in people of different age ranges and fitness. Jumping ability can be analyzed through different variables, and the most commonly used are fly time and jump height. They can be obtained by a variety of measuring devices, but most are limited to laboratory use only. The current generation of smartphones contains inertial sensors that are able to record kinematic variables for human motion analysis, since they are tools for easy access and portability for clinical use. The aim of this study was to describe and analyze the kinematics characteristics using the inertial sensor incorporated in the iPhone 4S, the lower limbs strength through a manual dynamometer, and the jump variables obtained with a contact mat in the squat jump and countermovement jump tests (fly time and jump height) from a cohort of healthy people. A cross sectional study was conducted on a population of healthy young adults. Twenty-seven participants performed three trials (n=81 jumps) of squat jump and countermovement jump tests. Acceleration variables were measured through a smartphone's inertial sensor. Additionally, jump variables from a contact mat and lower limbs dynamometry were collected. In the present study, the kinematic variables derived from acceleration through the inertial sensor of a smartphone iPhone 4S, dynamometry of lower limbs with a handheld dynamometer, and the height and flight time with a contact mat have been described in vertical jump tests from a cohort of young healthy subjects. The development of the execution has been described, examined and identified in a squat jump test and countermovement jump test under acceleration variables that were obtained with the smartphone. The built-in iPhone 4S inertial sensor is able to measure acceleration variables while performing vertical jump tests for the squat jump and countermovement jump in healthy young adults. The acceleration
Quantum walks and search algorithms
Portugal, Renato
2013-01-01
This book addresses an interesting area of quantum computation called quantum walks, which play an important role in building quantum algorithms, in particular search algorithms. Quantum walks are the quantum analogue of classical random walks. It is known that quantum computers have great power for searching unsorted databases. This power extends to many kinds of searches, particularly to the problem of finding a specific location in a spatial layout, which can be modeled by a graph. The goal is to find a specific node knowing that the particle uses the edges to jump from one node to the next. This book is self-contained with main topics that include: Grover's algorithm, describing its geometrical interpretation and evolution by means of the spectral decomposition of the evolution operater Analytical solutions of quantum walks on important graphs like line, cycles, two-dimensional lattices, and hypercubes using Fourier transforms Quantum walks on generic graphs, describing methods to calculate the limiting d...
Realized Jump Risk and Equity Return in China
Directory of Open Access Journals (Sweden)
Guojin Chen
2014-01-01
Full Text Available We utilize the realized jump components to explore a new jump (including nonsystematic jump and systematic jump risk factor model. After estimating daily realized jumps from high-frequency transaction data of the Chinese A-share stocks, we calculate monthly jump size, monthly jump standard deviation, and monthly jump arrival rate and then use those monthly jump factors to explain the return of the following month. Our empirical results show that the jump tail risk can explain the equity return. For the large capital-size stocks, large cap stock portfolios, and index, one-month lagged jump risk factor significantly explains the asset return variation. Our results remain the same even when we add the size and value factors in the robustness tests.
The effect of assisted jumping on vertical jump height in high-performance volleyball players.
Sheppard, Jeremy M; Dingley, Andrew A; Janssen, Ina; Spratford, Wayne; Chapman, Dale W; Newton, Robert U
2011-01-01
Assisted jumping may be useful in training higher concentric movement speed in jumping, thereby potentially increasing the jumping abilities of athletes. The purpose of this study was to evaluate the effects of assisted jump training on counter-movement vertical jump (CMVJ) and spike jump (SPJ) ability in a group of elite male volleyball players. Seven junior national team volleyball players (18.0±1.0 yrs, 200.4±6.7 cm, and 84.0±7.2 kg) participated in this within-subjects cross-over counter-balanced training study. Assisted training involved 3 sessions per week of CMVJ training with 10 kg of assistance, applied through use of a bungee system, whilst normal jump training involved equated volume of unassisted counter-movement vertical jumps. Training periods were 5 weeks duration, with a 3-week wash-out separating them. Prior to and at the conclusion of each training period jump testing for CMVJ and SPJ height was conducted. Assisted jump training resulted in gains of 2.7±0.7 cm (pSports Medicine Australia. All rights reserved.
Strength Determinants of Jump Height in the Jump Throw Movement in Women Handball Players.
McGhie, David; Østerås, Sindre; Ettema, Gertjan; Paulsen, Gøran; Sandbakk, Øyvind
2018-06-08
McGhie, D, Østerås, S, Ettema, G, Paulsen, G, and Sandbakk, Ø. Strength determinants of jump height in the jump throw movement in women handball players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of the study was to improve the understanding of the strength demands of a handball-specific jump through examining the associations between jump height in a jump throw jump (JTJ) and measures of lower-body maximum strength and impulse in handball players. For comparison, whether the associations between jump height and strength differed between the JTJ and the customarily used countermovement jump (CMJ) was also examined. Twenty women handball players from a Norwegian top division club participated in the study. Jump height was measured in the JTJ and in unilateral and bilateral CMJ. Lower-body strength (maximum isometric force, one-repetition maximum [1RM], impulse at ∼60% and ∼35% 1RM) was measured in seated leg press. The associations between jump height and strength were assessed with correlation analyses and t-tests of dependent r's were performed to determine if correlations differed between jump tests. Only impulse at ∼35% 1RM correlated significantly with JTJ height (p jump height and strength were significantly weaker in the JTJ than in both CMJ tests for all strength measures (p = 0.001-0.044) except one. Maximum strength and impulse at ∼60% 1RM did not seem to sufficiently capture the capabilities associated with JTJ height, highlighting the importance of employing tests targeting performance-relevant neuromuscular characteristics when assessing jump-related strength in handball players. Further, CMJ height seemed to represent a wider range of strength capabilities and care should be taken when using it as a proxy for handball-specific movements.
International Nuclear Information System (INIS)
Syphers, M.J.; Ahrens, L.; van Asselt, W.; Brennan, J.M.
1994-01-01
In an attempt to generate a lossless crossing of an accelerator's transition energy, one procedure is to alter the transition energy of the accelerator quickly as the beam passes through this energy region by changing the optics of the lattice -- a so-called ''transition jump,'' or '' γt -jump'' scheme. Such a system was first implemented at CERN and later adopted at other accelerator laboratories. A scheme for the AGS was developed in 1986. A description of the AGS γt -jump system, and recent results from its commissioning are presented in this report
Predicting vertical jump height from bar velocity.
García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén
2015-06-01
The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s(-2)). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r(2) = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r(2) = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key pointsVertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.The relationship between the point at which bar acceleration is less than -9.81 m·s(-2) and the real take-off is affected by the velocity of movement.Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance.
Measurements of K shell absorption jump factors and jump ratios using EDXRF technique
Kacal, Mustafa Recep; Han, İbrahim; Akman, Ferdi
2015-04-01
In the present work, the K-shell absorption jump factors and jump ratios for 30 elements between Ti ( Z = 22) and Er ( Z = 68) were measured by energy dispersive X-ray fluorescence (EDXRF) technique. The jump factors and jump ratios for these elements were determined by measuring the K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to- Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using an Am-241 radioactive point source and a Si (Li) detector in direct excitation and transmission experimental geometry. The results for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.
The Effects of Aquatic Plyometric Training on Repeated Jumps, Drop Jumps and Muscle Damage.
Jurado-Lavanant, A; Alvero-Cruz, J R; Pareja-Blanco, F; Melero-Romero, C; Rodríguez-Rosell, D; Fernandez-Garcia, J C
2015-09-22
The purpose of this study was to compare the effects of land- vs. aquatic based plyometric training programs on the drop jump, repeated jump performance and muscle damage. Sixty-five male students were randomly assigned to one of 3 groups: aquatic plyometric training group (APT), plyometric training group (PT) and control group (CG). Both experimental groups trained twice a week for 10 weeks performing the same number of sets and total jumps. The following variables were measured prior to, halfway through and after the training programs: creatine kinase (CK) concentration, maximal height during a drop jump from the height of 30 (DJ30) and 50 cm (DJ50), and mean height during a repeated vertical jump test (RJ). The training program resulted in a significant increase (Pplyometric training, PT produced greater gains on reactive jumps performance than APT. © Georg Thieme Verlag KG Stuttgart · New York.
Structure of the Balmer jump. The isolated hydrogen atom
Calvo, F.; Belluzzi, L.; Steiner, O.
2018-06-01
Context. The spectrum of the hydrogen atom was explained by Bohr more than one century ago. We revisit here some of the aspects of the underlying quantum structure, with a modern formalism, focusing on the limit of the Balmer series. Aims: We investigate the behaviour of the absorption coefficient of the isolated hydrogen atom in the neighbourhood of the Balmer limit. Methods: We analytically computed the total cross-section arising from bound-bound and bound-free transitions in the isolated hydrogen atom at the Balmer limit, and established a simplified semi-analytical model for the surroundings of that limit. We worked within the framework of the formalism of Landi Degl'Innocenti & Landolfi (2004, Astrophys. Space Sci. Lib., 307), which permits an almost straight-forward generalization of our results to other atoms and molecules, and which is perfectly suitable for including polarization phenomena in the problem. Results: We analytically show that there is no discontinuity at the Balmer limit, even though the concept of a "Balmer jump" is still meaningful. Furthermore, we give a possible definition of the location of the Balmer jump, and we check that this location is dependent on the broadening mechanisms. At the Balmer limit, we compute the cross-section in a fully analytical way. Conclusions: The Balmer jump is produced by a rapid drop of the total Balmer cross-section, yet this variation is smooth and continuous when both bound-bound and bound-free processes are taken into account, and its shape and location is dependent on the broadening mechanisms.
Option Panels in Pure-Jump Settings
DEFF Research Database (Denmark)
Andersen, Torben Gustav; Fusari, Nicola; Todorov, Viktor
We develop parametric inference procedures for large panels of noisy option data in the setting where the underlying process is of pure-jump type, i.e., evolve only through a sequence of jumps. The panel consists of options written on the underlying asset with a (different) set of strikes...... specification for the risk-neutral asset return dynamics, the option prices are nonlinear functions of a time-invariant parameter vector and a time-varying latent state vector (or factors). Furthermore, no-arbitrage restrictions impose a direct link between some of the quantities that may be identified from...... the return and option data. These include the so-called jump activity index as well as the time-varying jump intensity. We propose penalized least squares estimation in which we minimize L_2 distance between observed and model-implied options and further penalize for the deviation of model-implied quantities...
Human Long Jump — A Deductive Approach
Directory of Open Access Journals (Sweden)
Miloš Jovanović
2012-10-01
Full Text Available This paper presents a useful application of a generalized approach to the modelling of human and humanoid motion using the deductive approach. It starts with formulating a completely general problem and deriving different real situations as special cases. The concept and the software realization are verified by comparing the results with the ones obtained using “classical” software for one well-known particular problem – biped walking. New applicability and potentials of the proposed method are demonstrated by simulation of a selected example – the long jump. The simulated motion included jumping and landing on the feet (after a jump. Additional analysis is done in the paper regarding the joint torque and joint angle during the jumping. Separate stages of the simulation are defined and explained.
Volatility jumps and their economic determinants
DEFF Research Database (Denmark)
Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo
that there is a positive probability of jumps in volatility. A common factor in the volatility jumps is shown to be related to a set of financial covariates (such as variance risk premium, S&P500 volume, credit-default swap, and federal fund rates). The credit-default swap on US banks and variance risk premium have...... predictive power on expected jump moves, thus confirming the common interpretation that sudden and large increases in equity volatility can be anticipated by credit deterioration of the US bank sector as well as changes in the market expectations of future risks. Finally, the model is extended to incorporate...... the credit-default swap and the variance risk premium in the dynamics of the jump size and intensity....
A simple strategy for jumping straight up.
Hemami, Hooshang; Wyman, Bostwick F
2012-05-01
Jumping from a stationary standing position into the air is a transition from a constrained motion in contact with the ground to an unconstrained system not in contact with the ground. A simple case of the jump, as it applies to humans, robots and humanoids, is studied in this paper. The dynamics of the constrained rigid body are expanded to define a larger system that accommodates the jump. The formulation is applied to a four-link, three-dimensional system in order to articulate the ballistic motion involved. The activity of the muscular system and the role of the major sagittal muscle groups are demonstrated. The control strategy, involving state feedback and central feed forward signals, is formulated and computer simulations are presented to assess the feasibility of the formulations, the strategy and the jump. Copyright © 2012 Elsevier Inc. All rights reserved.
A Correction Equation for Jump Height Measured Using the Just Jump System.
McMahon, John J; Jones, Paul A; Comfort, Paul
2016-05-01
To determine the concurrent validity and reliability of the popular Just Jump system (JJS) for determining jump height and, if necessary, provide a correction equation for future reference. Eighteen male college athletes performed 3 bilateral countermovement jumps (CMJs) on 2 JJSs (alternative method) that were placed on top of a force platform (criterion method). Two JJSs were used to establish consistency between systems. Jump height was calculated from flight time obtained from the JJS and force platform. Intraclass correlation coefficients (ICCs) demonstrated excellent within-session reliability of the CMJ height measurement derived from both the JJS (ICC = .96, P jump height (0.46 ± 0.09 m vs 0.33 ± 0.08 m) than the force platform (P jump height = (0.8747 × alternative jump height) - 0.0666. The JJS provides a reliable but overestimated measure of jump height. It is suggested, therefore, that practitioners who use the JJS as part of future work apply the correction equation presented in this study to resultant jump-height values.
Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012–2014
Directory of Open Access Journals (Sweden)
Karen Ruse
2015-10-01
Full Text Available Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%. There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075% and steeplechases, 14 fatalities per 1000 starts (1.4%. Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these Animals 2015, 5 1073 data in light of public controversy, political debate, and industry regulation related to jump horse safety.
Ruse, Karen; Davison, Aidan; Bridle, Kerry
2015-10-22
Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these Animals 2015, 5 1073 data in light of public controversy, political debate, and industry regulation related to jump horse safety.
Jump spillover between oil prices and exchange rates
Li, Xiao-Ping; Zhou, Chun-Yang; Wu, Chong-Feng
2017-11-01
In this paper, we investigate the jump spillover effects between oil prices and exchange rates. To identify the latent historical jumps for exchange rates and oil prices, we use a Bayesian MCMC approach to estimate the stochastic volatility model with correlated jumps in both returns and volatilities for each. We examine the simultaneous jump intensities and the conditional jump spillover probabilities between oil prices and exchange rates, finding strong evidence of jump spillover effects. Further analysis shows that the jump spillovers are mainly due to exogenous events such as financial crises and geopolitical events. Thus, the findings have important implications for financial risk management.
A multiplicity jump trigger using silicon planes
International Nuclear Information System (INIS)
Alexopoulos, T.; Erwin, A.R.
1993-01-01
Since silicon tracking planes are already present in a B decay experiment, it is an attractive idea to use these as part of a multiplicity jump detector. Two average B decays would produce a multiplicity jump of around 10 in the final state. Such a trigger has been tried for a fixed target Charm experiment with disappointing success. The failure was attributed to the difficulty in adequately controlling the gains of a large number of microstrip amplifies
Portfolio Selection with Jumps under Regime Switching
Directory of Open Access Journals (Sweden)
Lin Zhao
2010-01-01
Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.
Jumps in binomial AR(1) processes
Weiß , Christian H.
2009-01-01
Abstract We consider the binomial AR(1) model for serially dependent processes of binomial counts. After a review of its definition and known properties, we investigate marginal and serial properties of jumps in such processes. Based on these results, we propose the jumps control chart for monitoring a binomial AR(1) process. We show how to evaluate the performance of this control chart and give design recommendations. correspondance: Tel.: +49 931 31 84968; ...
Hydrodynamics of vertical jumping in Archer fish
Techet, Alexandra H.; Mendelson, Leah
2017-11-01
Vertical jumping for aerial prey from an aquatic environment requires both propulsive power and precise aim to succeed. Rapid acceleration to a ballistic velocity sufficient for reaching the prey height occurs before the fish leaves the water completely and experiences a thousandfold drop in force-producing ability. In addition to speed, accuracy and stability are crucial for successful feeding by jumping. This talk examines the physics of jumping using the archer fish as a model. Better known for their spitting abilities, archer fish will jump multiple body lengths out of the water for prey capture, from a stationary position just below the free surface. Modulation of oscillatory body kinematics and use of multiple fins for force production are identified as methods through which the fish can meet requirements for both acceleration and stabilization in limited space. Quantitative 3D PIV wake measurements reveal how variations in tail kinematics relate to thrust production throughout the course of a jumping maneuver and over a range of jump heights. By performing measurements in 3D, the timing, interactions, and relative contributions to thrust and lateral forces from each fin can be evaluated, elucidating the complex hydrodynamics that enable archer fish water exit.
Performance analysis of jump-gliding locomotion for miniature robotics.
Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M
2015-03-26
Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.
Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012–2014
Ruse, Karen; Davison, Aidan; Bridle, Kerry
2015-01-01
Simple Summary This paper documents the dynamics of Australian thoroughbred jump racing in the 2012, 2013, and 2014 seasons with the aim of informing debate about risks to horses and the future of this activity. We conclude that the safety of Australian jump racing has improved in recent years but that steeplechases are considerably riskier for horses than hurdle races. Abstract Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these data in light of public controversy, political debate, and industry regulation related to jump horse safety. PMID:26506396
Jumping to conclusions in schizophrenia
Directory of Open Access Journals (Sweden)
Evans SL
2015-07-01
Full Text Available Simon L Evans,1 Bruno B Averbeck,2 Nicholas Furl31School of Psychology, University of Sussex, Brighton, East Sussex, UK; 2Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA; 3Department of Psychology, Royal Holloway, University of London, Egham, Surrey, UKAbstract: Schizophrenia is a mental disorder associated with a variety of symptoms, including hallucinations, delusions, social withdrawal, and cognitive dysfunction. Impairments on decision-making tasks are routinely reported: evidence points to a particular deficit in learning from and revising behavior following feedback. In addition, patients tend to make hasty decisions when probabilistic judgments are required. This is known as “jumping to conclusions” (JTC and has typically been demonstrated by presenting participants with colored beads drawn from one of two “urns” until they claim to be sure which urn the beads are being drawn from (the proportions of colors vary in each urn. Patients tend to make early decisions on this task, and there is evidence to suggest that a hasty decision-making style might be linked to delusion formation and thus be of clinical relevance. Various accounts have been proposed regarding what underlies this behavior. In this review, we briefly introduce the disorder and the decision-making deficits associated with it. We then explore the evidence for each account of JTC in the context of a wider decision-making deficit and then go on to summarize work exploring JTC in healthy controls using pharmacological manipulations and functional imaging. Finally, we assess whether JTC might have a role in therapy.Keywords: ketamine, decision making, delusions, fMRI, urn task
The reliability of vertical jump tests between the Vertec and My Jump phone application.
Yingling, Vanessa R; Castro, Dimitri A; Duong, Justin T; Malpartida, Fiorella J; Usher, Justin R; O, Jenny
2018-01-01
The vertical jump is used to estimate sports performance capabilities and physical fitness in children, elderly, non-athletic and injured individuals. Different jump techniques and measurement tools are available to assess vertical jump height and peak power; however, their use is limited by access to laboratory settings, excessive cost and/or time constraints thus making these tools oftentimes unsuitable for field assessment. A popular field test uses the Vertec and the Sargent vertical jump with countermovement; however, new low cost, easy to use tools are becoming available, including the My Jump iOS mobile application (app). The purpose of this study was to assess the reliability of the My Jump relative to values obtained by the Vertec for the Sargent stand and reach vertical jump (VJ) test. One hundred and thirty-five healthy participants aged 18-39 years (94 males, 41 females) completed three maximal Sargent VJ with countermovement that were simultaneously measured using the Vertec and the My Jump . Jump heights were quantified for each jump and peak power was calculated using the Sayers equation. Four separate ICC estimates and their 95% confidence intervals were used to assess reliability. Two analyses (with jump height and calculated peak power as the dependent variables, respectively) were based on a single rater, consistency, two-way mixed-effects model, while two others (with jump height and calculated peak power as the dependent variables, respectively) were based on a single rater, absolute agreement, two-way mixed-effects model. Moderate to excellent reliability relative to the degree of consistency between the Vertec and My Jump values was found for jump height (ICC = 0.813; 95% CI [0.747-0.863]) and calculated peak power (ICC = 0.926; 95% CI [0.897-0.947]). However, poor to good reliability relative to absolute agreement for VJ height (ICC = 0.665; 95% CI [0.050-0.859]) and poor to excellent reliability relative to absolute agreement for peak power
International Nuclear Information System (INIS)
Kragh, Helge
2000-01-01
Physicists often complain that the phrase q uantum leap'' is used erroneously, if harmlessly, by people to describe a large jump or change. Yet this month the physics community is celebrating the 100th anniversary of what must count as the beginning of the biggest quantum leap in the history of science, whichever way you define the phrase. On 14 December 1900 Max Planck presented a paper on the radiation emitted by a black body at a meeting of the German Physical Society in Berlin. This event is generally taken to mark the start of the quantum century, though few people realized it at the time - not even Planck himself. (U.K.)
Jump locations of jump-diffusion processes with state-dependent rates
International Nuclear Information System (INIS)
Miles, Christopher E; Keener, James P
2017-01-01
We propose a general framework for studying statistics of jump-diffusion systems driven by both Brownian noise (diffusion) and a jump process with state-dependent intensity. Of particular natural interest in many physical systems are the jump locations: the system evaluated at the jump times. As an example, this could be the voltage at which a neuron fires, or the so-called ‘threshold voltage’. However, the state-dependence of the jump rate provides direct coupling between the diffusion and jump components, making it difficult to disentangle the two to study individually. In this work, we provide an iterative map formulation of the sequence of distributions of jump locations. The distributions computed by this map can be used to elucidate other interesting quantities about the process, including statistics of the interjump times. Ultimately, the limit of the map reveals that knowledge of the stationary distribution of the full process is sufficient to recover (but not necessarily equal to) the distribution of jump locations. We propose two biophysical examples to illustrate the use of this framework to provide insight about a system. We find that a sharp threshold voltage emerges robustly in a simple stochastic integrate-and-fire neuronal model. The interplay between the two sources of noise is also investigated in a stepping model of molecular motor in intracellular transport pulling a diffusive cargo. (paper)
Experimental study of the hydraulic jump in a hydraulic jump in a ...
African Journals Online (AJOL)
The hydraulic jump in a sloped rectangular channel is theoretically and experimentally examined. The study aims to determine the effect of the channel's slope on the sequent depth ratio of the jump. A theoretical relation is proposed for the inflow Froude number as function of the sequent depth ratio and the channel slope.
Drop jumping. II. The influence of dropping height on the biomechanics of drop jumping
Bobbert, M F; Huijing, P A; van Ingen Schenau, G J
In the literature, athletes preparing for explosive activities are recommended to include drop jumping in their training programs. For the execution of drop jumps, different techniques and different dropping heights can be used. This study was designed to investigate for the performance of bounce
Increase in Jumping Height Associated with Maximal Effort Vertical Depth Jumps.
Bedi, John F.; And Others
1987-01-01
In order to assess if there existed a statistically significant increase in jumping performance when dropping from different heights, 32 males, aged 19 to 26, performed a series of maximal effort vertical jumps after dropping from eight heights onto a force plate. Results are analyzed. (Author/MT)
Davis, Caitlin M; Reddish, Michael J; Dyer, R Brian
2017-05-05
Time-resolved temperature-jump (T-jump) coupled with fluorescence and infrared (IR) spectroscopy is a powerful technique for monitoring protein dynamics. Although IR spectroscopy of the polypeptide amide I mode is more technically challenging, it offers complementary information because it directly probes changes in the protein backbone, whereas, fluorescence spectroscopy is sensitive to the environment of specific side chains. With the advent of widely tunable quantum cascade lasers (QCL) it is possible to efficiently probe multiple IR frequencies with high sensitivity and reproducibility. Here we describe a dual time-resolved T-jump fluorescence and IR spectrometer and its application to study protein folding dynamics. A Q-switched Ho:YAG laser provides the T-jump source for both time-resolved IR and fluorescence spectroscopy, which are probed by a QCL and Ti:Sapphire laser, respectively. The Ho:YAG laser simultaneously pumps the time-resolved IR and fluorescence spectrometers. The instrument has high sensitivity, with an IR absorbance detection limit of jump induced difference spectrum from 50ns to 0.5ms. This study demonstrates the power of the dual time-resolved T-jump fluorescence and IR spectroscopy to resolve complex folding mechanisms by complementary IR absorbance and fluorescence measurements of protein dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.
The effect of wind on jumping distance in ski jumping--fairness assessed.
Virmavirta, Mikko; Kivekäs, Juha
2012-09-01
The special wind compensation system recently adopted by Fédération Internationale de Ski (FIS; International Ski Federation) to consider the effects of changing wind conditions has caused some controversy. Here, the effect of wind on jumping distance in ski jumping was studied by means of computer simulation and compared with the wind compensation factors used by FIS during the World Cup season 2009/2010. The results showed clearly that the effect of increasing head/tail wind on jumping distance is not linear: +17.4 m/-29.1 m, respectively, for a wind speed of 3 m/s. The linear formula used in the trial period of the wind compensation system was found to be appropriate only for a limited range of jumping distances as the gradient of the landing slope slows down the rate of distance change in long jumps.
Mayato, R; Egusquiza, I
2002-01-01
The treatment of time in quantum mechanics is still an important and challenging open question in the foundation of the theory. This book describes the problems, and the attempts and achievements in defining, formalizing and measuring different time quantities in quantum theory, such as the parametric (clock) time, tunneling times, decay times, dwell times, delay times, arrival times or jump times. This multiauthored book, written as an introductory guide for the non-initiated as well as a useful source of information for the expert, covers many of the open questions. A brief historical overview is to be found in the introduction. It is followed by 12 chapters devoted to conceptual and theoretical investigations as well as experimental issues in quantum-mechanical time measurements. This unique monograph should attract physicists as well as philosophers of science working in the foundations of quantum physics.
Filtering and control of stochastic jump hybrid systems
Yao, Xiuming; Zheng, Wei Xing
2016-01-01
This book presents recent research work on stochastic jump hybrid systems. Specifically, the considered stochastic jump hybrid systems include Markovian jump Ito stochastic systems, Markovian jump linear-parameter-varying (LPV) systems, Markovian jump singular systems, Markovian jump two-dimensional (2-D) systems, and Markovian jump repeated scalar nonlinear systems. Some sufficient conditions are first established respectively for the stability and performances of those kinds of stochastic jump hybrid systems in terms of solution of linear matrix inequalities (LMIs). Based on the derived analysis conditions, the filtering and control problems are addressed. The book presents up-to-date research developments and novel methodologies on stochastic jump hybrid systems. The contents can be divided into two parts: the first part is focused on robust filter design problem, while the second part is put the emphasis on robust control problem. These methodologies provide a framework for stability and performance analy...
Miura, Ken; Yamamoto, Masayoshi; Tamaki, Hiroyuki; Zushi, Koji
2010-01-01
This study was conducted to obtain useful information for developing training techniques for the running 1-legged vertical jump in basketball (lay-up shot jump). The ability to perform the lay-up shot jump and various basic jumps was measured by testing 19 male basketball players. The basic jumps consisted of the 1-legged repeated rebound jump, the 2-legged repeated rebound jump, and the countermovement jump. Jumping height, contact time, and jumping index (jumping height/contact time) were measured and calculated using a contact mat/computer system that recorded the contact and air times. The jumping index indicates power. No significant correlation existed between the jumping height and contact time of the lay-up shot jump, the 2 components of the lay-up shot jump index. As a result, jumping height and contact time were found to be mutually independent abilities. The relationships in contact time between the lay-up shot jump to the 1-legged repeated rebound jump and the 2-legged repeated rebound jump were correlated on the same significance levels (p jumping height existed between the 1-legged repeated rebound jump and the lay-up shot jump (p jumping height between the lay-up shot jump and both the 2-legged repeated rebound jump and countermovement jump. The lay-up shot index correlated more strongly to the 1-legged repeated rebound jump index (p jump index (p jump is effective in improving both contact time and jumping height in the lay-up shot jump.
Temperature jump boundary conditions in radiation diffusion
International Nuclear Information System (INIS)
Alonso, C.T.
1976-12-01
The radiation diffusion approximation greatly simplifies radiation transport problems. Yet the application of this method has often been unnecessarily restricted to optically thick regions, or has been extended through the use of such ad hoc devices as flux limiters. The purpose of this paper is to review and draw attention to the use of the more physically appropriate temperature jump boundary conditions for extending the range of validity of the diffusion approximation. Pioneering work has shown that temperature jump boundary conditions remove the singularity in flux that occurs in ordinary diffusion at small optical thicknesses. In this review paper Deissler's equations for frequency-dependent jump boundary conditions are presented and specific geometric examples are calculated analytically for steady state radiation transfer. When jump boundary conditions are applied to radiation diffusion, they yield exact solutions which are naturally flux- limited and geometry-corrected. We believe that the presence of temperature jumps on source boundaries is probably responsible in some cases for the past need for imposing ad hoc flux-limiting constraints on pure diffusion solutions. The solution for transfer between plane slabs, which is exact to all orders of optical thickness, also provides a useful tool for studying the accuracy of computer codes
Scaling the viscous circular hydraulic jump
Argentina, Mederic; Cerda, Enrique; Duchesne, Alexis; Limat, Laurent
2017-11-01
The formation mechanism of hydraulic jumps has been proposed by Belanger in 1828 and rationalised by Lord Rayleigh in 1914. As the Froude number becomes higher than one, the flow super criticality induces an instability which yields the emergence of a steep structure at the fluid surface. Strongly deformed liquid-air interface can be observed as a jet of viscous fluid impinges a flat boundary at high enough velocity. In this experimental setup, the location of the jump depends on the viscosity of the liquid, as shown by T. Bohr et al. in 1997. In 2014, A. Duchesne et al. have established the constancy of the Froude number at jump. Hence, it remains a contradiction, in which the radial hydraulic jump location might be explained through inviscid theory, but is also viscosity dependent. We present a model based on the 2011 Rojas et al. PRL, which solves this paradox. The agreement with experimental measurements is excellent not only for the prediction of the position of the hydraulic jump, but also for the determination of the fluid thickness profile. We predict theoretically the critical value of the Froude number, which matches perfectly to that measured by Duchesne et al. We acknowledge the support of the CNRS and the Universit Cte d'Azur, through the IDEX funding.
A locust-inspired miniature jumping robot.
Zaitsev, Valentin; Gvirsman, Omer; Ben Hanan, Uri; Weiss, Avi; Ayali, Amir; Kosa, Gabor
2015-11-25
Unmanned ground vehicles are mostly wheeled, tracked, or legged. These locomotion mechanisms have a limited ability to traverse rough terrain and obstacles that are higher than the robot's center of mass. In order to improve the mobility of small robots it is necessary to expand the variety of their motion gaits. Jumping is one of nature's solutions to the challenge of mobility in difficult terrain. The desert locust is the model for the presented bio-inspired design of a jumping mechanism for a small mobile robot. The basic mechanism is similar to that of the semilunar process in the hind legs of the locust, and is based on the cocking of a torsional spring by wrapping a tendon-like wire around the shaft of a miniature motor. In this study we present the jumping mechanism design, and the manufacturing and performance analysis of two demonstrator prototypes. The most advanced jumping robot demonstrator is power autonomous, weighs 23 gr, and is capable of jumping to a height of 3.35 m, covering a distance of 1.37 m.
Biomechanics of stair walking and jumping.
Loy, D J; Voloshin, A S
1991-01-01
Physical activities such as stair walking and jumping result in increased dynamic loading on the human musculoskeletal system. Use of light weight, externally attached accelerometers allows for in-vivo monitoring of the shock waves invading the human musculoskeletal system during those activities. Shock waves were measured in four subjects performing stair walking up and down, jumping in place and jumping off a fixed elevation. The results obtained show that walking down a staircase induced shock waves with amplitude of 130% of that observed in walking up stairs and 250% of the shock waves experienced in level gait. The jumping test revealed levels of the shock waves nearly eight times higher than that in level walking. It was also shown that the shock waves invading the human musculoskeletal system may be generated not only by the heel strike, but also by the metatarsal strike. To moderate the risk of degenerative joint disorders four types of viscoelastic insoles were utilized to reduce the impact generated shock waves. The insoles investigated were able to reduce the amplitude of the shock wave by between 9% and 41% depending on the insole type and particular physical activity. The insoles were more effective in the reduction of the heel strike impacts than in the reduction of the metatarsal strike impacts. In all instances, the shock attenuation capacities of the insoles tested were greater in the jumping trials than in the stair walking studies. The insoles were ranked in three groups on the basis of their shock absorbing capacity.
Vector dark matter detection using the quantum jump of atoms
Yang, Qiaoli; Di, Haoran
2018-05-01
The hidden sector U(1) vector bosons created from inflationary fluctuations can be a substantial fraction of dark matter if their mass is around 10-5 eV. The creation mechanism makes the vector bosons' energy spectral density ρcdm / ΔE very high. Therefore, the dark electric dipole transition rate in atoms is boosted if the energy gap between atomic states equals the mass of the vector bosons. By using the Zeeman effect, the energy gap between the 2S state and the 2P state in hydrogen atoms or hydrogen like ions can be tuned. The 2S state can be populated with electrons due to its relatively long life, which is about 1/7 s. When the energy gap between the semi-ground 2S state and the 2P state matches the mass of the cosmic vector bosons, induced transitions occur and the 2P state subsequently decays into the 1S state. The 2 P → 1 S decay emitted Lyman-α photons can then be registered. The choices of target atoms depend on the experimental facilities and the mass ranges of the vector bosons. Because the mass of the vector boson is connected to the inflation scale, the proposed experiment may provide a probe to inflation.
Energy Technology Data Exchange (ETDEWEB)
Seyed Majid Saberi Fathi
2007-07-15
In this thesis, we first study Lorentz gas as a billiard ball with elastic collision with the obstacles and a system of hard spheres in 2-dimensions. We study a numerical simulation of the dynamical system and we investigate the entropy increasing in non-equilibrium with time under the effect of collisions and its relation to positive Lyapunov exponents. Then, we study a decay model in a quantum system called Friedrichs model. We consider coupling of the kaons and environment with continuous energies. Then, we show that this model is well adapted to describe oscillation, regeneration, decay and CP violation of a kaonic system. In addition, we apply in the Friedrichs model, the time super-operator formalism that predicts the resonance, i.e. the survival probability of the instable states. (author)
Serious ski jumping injuries in Norway.
Wester, K
1985-01-01
Injuries caused by ski jumping have been poorly investigated. Among approximately 2,200 licensed jumpers in Norway, there occurred at least 12 injuries with a permanent medical disability of greater than or equal to 10%. The risk of being seriously injured is approximately 5% in a 5 year period (1977 to 1981); it is higher in the age group 15 to 17 years. Seven injuries were very serious [four central nervous system (CNS) lesions, two leg amputations, and one blindness of one eye], and five were less serious (sequelae to fractures of the lower extremities). The first jump of the day is particularly dangerous, and so is the beginning and end of the season. It seems dangerous to use more than one standard heel block. Poor preparation of the jump may have contributed to the accidents. Based on the findings, several prophylactic measures are suggested.
Recent Advancements in Lightning Jump Algorithm Work
Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.
2010-01-01
In the past year, the primary objectives were to show the usefulness of total lightning as compared to traditional cloud-to-ground (CG) networks, test the lightning jump algorithm configurations in other regions of the country, increase the number of thunderstorms within our thunderstorm database, and to pinpoint environments that could prove difficult for any lightning jump configuration. A total of 561 thunderstorms have been examined in the past year (409 non-severe, 152 severe) from four regions of the country (North Alabama, Washington D.C., High Plains of CO/KS, and Oklahoma). Results continue to indicate that the 2 lightning jump algorithm configuration holds the most promise in terms of prospective operational lightning jump algorithms, with a probability of detection (POD) at 81%, a false alarm rate (FAR) of 45%, a critical success index (CSI) of 49% and a Heidke Skill Score (HSS) of 0.66. The second best performing algorithm configuration was the Threshold 4 algorithm, which had a POD of 72%, FAR of 51%, a CSI of 41% and an HSS of 0.58. Because a more complex algorithm configuration shows the most promise in terms of prospective operational lightning jump algorithms, accurate thunderstorm cell tracking work must be undertaken to track lightning trends on an individual thunderstorm basis over time. While these numbers for the 2 configuration are impressive, the algorithm does have its weaknesses. Specifically, low-topped and tropical cyclone thunderstorm environments are present issues for the 2 lightning jump algorithm, because of the suppressed vertical depth impact on overall flash counts (i.e., a relative dearth in lightning). For example, in a sample of 120 thunderstorms from northern Alabama that contained 72 missed events by the 2 algorithm 36% of the misses were associated with these two environments (17 storms).
Validity of a Jump Mat for assessing Countermovement Jump Performance in Elite Rugby Players.
Dobbin, Nick; Hunwicks, Richard; Highton, Jamie; Twist, Craig
2017-02-01
This study determined the validity of the Just Jump System ® (JJS) for measuring flight time, jump height and peak power output (PPO) in elite rugby league players. 37 elite rugby league players performed 6 countermovement jumps (CMJ; 3 with and 3 without arms) on a jump mat and force platform. A sub-sample (n=28) was used to cross-validate the equations for flight time, jump height and PPO. The JJS systematically overestimated flight time and jump height compared to the force platform (Pjump height ( with R 2 =0.945; without R 2 =0.987). Our equations revealed no systematic difference between corrected and force platform scores and an improved the agreement for flight time (Ratio limits of agreement: with 1.00 vs. 1.36; without 1.00 vs. 1.16) and jump height ( with 1.01 vs. 1.34; without 1.01 vs. 1.15), meaning that our equations can be used to correct JJS scores for elite rugby players. While our equation improved the estimation of PPO ( with 1.02; without 1.01) compared to existing equations (Harman: 1.20; Sayers: 1.04), this only accounted for 64 and 69% of PPO. © Georg Thieme Verlag KG Stuttgart · New York.
CLIMATIC JUMP IN THE POLAR REGION (I)
ヤマモト, リョウザブロウ; イワシマ, タツヤ; ホシアイ, マコト; Ryozaburo, YAMAMOTO; Tatsuya, IWASHIMA; Makoto, HOSHIAI
1987-01-01
From the analysis of the climatic elements over Japan, we can detect the "climatic jumps" around the years 1920 and 1950,which is a new concept in the climatic diagnosis proposed by the present authors (R. YAMAMOTO et al. : J. Meteorol. Soc. Jpn., 63,1157,1985,64,273,1986). Taking account of several results which show the simultaneous occurrence of the climatic jumps of the surface air temperature, precipitation, etc., in the other regions by the other investigators, we may infer the "climati...
Does trampoline or hard surface jumping influence lower extremity alignment?
Akasaka, Kiyokazu; Tamura, Akihiro; Katsuta, Aoi; Sagawa, Ayako; Otsudo, Takahiro; Okubo, Yu; Sawada, Yutaka; Hall, Toby
2017-12-01
[Purpose] To determine whether repetitive trampoline or hard surface jumping affects lower extremity alignment on jump landing. [Subjects and Methods] Twenty healthy females participated in this study. All subjects performed a drop vertical jump before and after repeated maximum effort trampoline or hard surface jumping. A three-dimensional motion analysis system and two force plates were used to record lower extremity angles, moments, and vertical ground reaction force during drop vertical jumps. [Results] Knee extensor moment after trampoline jumping was greater than that after hard surface jumping. There were no significant differences between trials in vertical ground reaction force and lower extremity joint angles following each form of exercise. Repeated jumping on a trampoline increased peak vertical ground reaction force, hip extensor, knee extensor moments, and hip adduction angle, while decreasing hip flexion angle during drop vertical jumps. In contrast, repeated jumping on a hard surface increased peak vertical ground reaction force, ankle dorsiflexion angle, and hip extensor moment during drop vertical jumps. [Conclusion] Repeated jumping on the trampoline compared to jumping on a hard surface has different effects on lower limb kinetics and kinematics. Knowledge of these effects may be useful in designing exercise programs for different clinical presentations.
Fitzgerald, John S; Johnson, LuAnn; Tomkinson, Grant; Stein, Jesse; Roemmich, James N
2018-05-01
Mechanography during the vertical jump may enhance screening and determining mechanistic causes underlying physical performance changes. Utility of jump mechanography for evaluation is limited by scant test-retest reliability data on force-time variables. This study examined the test-retest reliability of eight jump execution variables assessed from mechanography. Thirty-two women (mean±SD: age 20.8 ± 1.3 yr) and 16 men (age 22.1 ± 1.9 yr) attended a familiarization session and two testing sessions, all one week apart. Participants performed two variations of the squat jump with squat depth self-selected and controlled using a goniometer to 80º knee flexion. Test-retest reliability was quantified as the systematic error (using effect size between jumps), random error (using coefficients of variation), and test-retest correlations (using intra-class correlation coefficients). Overall, jump execution variables demonstrated acceptable reliability, evidenced by small systematic errors (mean±95%CI: 0.2 ± 0.07), moderate random errors (mean±95%CI: 17.8 ± 3.7%), and very strong test-retest correlations (range: 0.73-0.97). Differences in random errors between controlled and self-selected protocols were negligible (mean±95%CI: 1.3 ± 2.3%). Jump execution variables demonstrated acceptable reliability, with no meaningful differences between the controlled and self-selected jump protocols. To simplify testing, a self-selected jump protocol can be used to assess force-time variables with negligible impact on measurement error.
A quantum extended Kalman filter
International Nuclear Information System (INIS)
Emzir, Muhammad F; Woolley, Matthew J; Petersen, Ian R
2017-01-01
In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements. (paper)
A quantum extended Kalman filter
Emzir, Muhammad F.; Woolley, Matthew J.; Petersen, Ian R.
2017-06-01
In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements.
Influence of Knee-to-Feet Jump Training on Vertical Jump and Hang Clean Performance.
Stark, Laura; Pickett, Karla; Bird, Michael; King, Adam C
2016-11-01
Stark, L, Pickett, K, Bird, M, and King, AC. Influence of knee-to-feet jump training on vertical jump and hang clean performance. J Strength Cond Res 30(11): 3084-3089, 2016-From a motor learning perspective, the practice/training environment can result in positive, negative, or neutral transfer to the testing conditions. The purpose of this study was to examine the training effect of a novel movement (knee-to-feet [K2F] jumps) and whether a 6-week training program induced a positive transfer effect to other power-related movements (vertical jump and hang clean [HC]). Twenty-six intercollegiate athletes from power-emphasized sports were paired and counter-balanced into a control (i.e., maintained their respective sport-specific lifting regimen) or an experimental group (i.e., completed a 6-week progressive training program of K2F jumps in addition to respective lifting regimen). A pre- and posttest design was used to investigate the effect of training on K2F jump height and transfer effect to vertical jump height (VJH) and 2-repetition maximum (RM) HC performance. A significant increase in K2F jump height was found for the experimental group. Vertical jump height significantly increased from pre- to posttest but no group or interaction (group × time) effect was found, and there were nonsignificant differences for HC. Posttest data showed significant correlations between all pairs of the selected exercises with the highest correlation between K2F jump height and VJ H (R = 0.40) followed by VJH and 2RM HC (R = 0.38) and 2RM HC and K2F jump height (R = 0.23). The results suggest that K2F jump training induced the desired learning effect but was specific to the movement in that no effect of transfer occurred to the other power-related movements. This finding is value for strength and condition professionals who design training programs to enhance athletic performance.
Filtering of a Markov Jump Process with Counting Observations
International Nuclear Information System (INIS)
Ceci, C.; Gerardi, A.
2000-01-01
This paper concerns the filtering of an R d -valued Markov pure jump process when only the total number of jumps are observed. Strong and weak uniqueness for the solutions of the filtering equations are discussed
Jumping on the Social Media Bandwagon
Blakeslee, Lori
2012-01-01
Should a school district jump on the social media bandwagon? Yes! Social media provide a low-cost way to communicate school district priorities, influence decision makers, and tell its story without filters. Equally important, social media are where constituents are spending a lot of their time. With more than 800 million members, Facebook is an…
International Nuclear Information System (INIS)
Calarco, T.; Datta, A.; Fedichev, P.; Zoller, P.; Pazy, E.
2003-01-01
We present an all-optical implementation of quantum computation using semiconductor quantum dots. Quantum memory is represented by the spin of an excess electron stored in each dot. Two-qubit gates are realized by switching on trion-trion interactions between different dots. State selectivity is achieved via conditional laser excitation exploiting Pauli exclusion principle. Read out is performed via a quantum-jump technique. We analyze the effect on our scheme's performance of the main imperfections present in real quantum dots: exciton decay, hole mixing, and phonon decoherence. We introduce an adiabatic gate procedure that allows one to circumvent these effects and evaluate quantitatively its fidelity
Jump as Far as You Can [Problem Solvers: Problem
Bofferding, Laura; Yigit, Melike
2013-01-01
The standing long jump was an Olympic event until 1912. In 1904, Ray Ewry set the world record for the longest standing long jump, which was about 11.5 feet, or 138 inches. Although the standing long jump is no longer an Olympic event, the Norwegians still include it in their National Competition, and Arne Tvervaag set a new world record at about…
Thomson's Jumping Ring over a Long Coil
Jeffery, Rondo N.; Amiri, Farhang
2018-01-01
The classic jumping ring apparatus consists of a coil with an iron core that extends out of the coil. A copper or aluminum ring placed over the iron core jumps upward when AC power is applied to the coil. In this paper we will examine a modified design of the jumping ring apparatus, called the "long-coil design." It allows the ring to…
Vorticity determination in a hydraulic jump by application of method ...
African Journals Online (AJOL)
The method of characteristics for solving systems of partial differential equations coupled with jump conditions is used in analysing flow downstream of a hydraulic jump instead of the normal analytical approach adopted in Hornung [1]. It is shown that the method of characteristics together with the jump conditions can ...
Scaling and jumping: Gravity loses grip on small jumpers
Scholz, M.N.; Bobbert, M.F.; van Soest, A.J.
2006-01-01
There are several ways to quantify jumping performance, a common definition being the height gained by the body's centre of mass (CM) in the airborne phase. Under this definition, jump height is determined by take-off velocity. According to the existing literature on jumping and scaling, take-off
Effect of early training on the jumping technique of horses
Santamaría, Susana; Bobbert, Maarten F.; Back, Willem; Barneveld, Ab; van Weeren, P. Rene
Objective - To investigate the effects of early training for jumping by comparing the jumping technique of horses that had received early training with that of horses raised conventionally. Animals - 40 Dutch Warmblood horses. Procedure - The horses were analyzed kinematically during free jumping at
International Nuclear Information System (INIS)
Taylor, P R; Baker, R E; Yates, C A
2015-01-01
In this paper we explore lattice-based position-jump models of diffusion, and the implications of introducing non-local jumping; particles can jump to a range of nearby boxes rather than only to their nearest neighbours. We begin by deriving conditions for equivalence with traditional local jumping models in the continuum limit. We then generalize a previously postulated implementation of the Robin boundary condition for a non-local process of arbitrary maximum jump length, and present a novel implementation of flux boundary conditions, again generalized for a non-local process of arbitrary maximum jump length. In both these cases we validate our results using stochastic simulation. We then proceed to consider two variations on the basic diffusion model: a hybrid local/non-local scheme suitable for models involving sharp concentration gradients, and the implementation of biased jumping. In all cases we show that non-local jumping can deliver substantial time savings for stochastic simulations. (paper)
Energy Technology Data Exchange (ETDEWEB)
Abram, I [Centre National d' Etudes des Telecommunications (CNET), 196 Avenue Henri Ravera, F-92220 Bagneux (France)
1999-02-01
Two of the most remarkable properties of light - squeezing and solitons - are being combined in a new generation of experiments that could revolutionize optics and communications. One area of application concerns the transmission and processing of classical (binary) information, in which the presence or absence of a soliton in a time-window corresponds to a ''1'' or ''0'', as in traditional optical-fibre communications. However, since solitons occur at fixed power levels, we do not have the luxury of being able to crank up the input power to improve the signal-to-noise ratio at the receiving end. Nevertheless, the exploitation of quantum effects such as squeezing could help to reduce noise and improve fidelity. In long-distance communications, where the signal is amplified every 50-100 kilometres or so, the soliton pulse is strongest just after the amplifier. Luckily this is where the bulk of the nonlinear interaction needed to maintain the soliton shape occurs. However, the pulse gets weaker as it propagates along the fibre, so the nonlinear interaction also becomes weakerand weaker. This means that dispersive effects become dominant until the next stage of amplification, where the nonlinearity takes over again. One problem is that quantum fluctuations in the amplifiers lead to random jumps in the central wavelength of the individual solitons, and this results in a random variation of the speed of individual solitons in the fibre. Several schemes have been devised to remove this excess noise and bring the train of solitons back to the orderly behaviour characteristic of a stable coherent state (e.g. the solitons could be passed through a spectral filter). Photon-number squeezing could also play a key role in solving this problem. For example, if the solitons are number-squeezed immediately after amplification, there will be a smaller uncertainty in the nonlinearity that keeps the soliton in shape and, therefore, there will also be less noise in the soliton. This
Option Valuation with Observable Volatility and Jump Dynamics
DEFF Research Database (Denmark)
Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae
Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...
Option Valuation with Observable Volatility and Jump Dynamics
DEFF Research Database (Denmark)
Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae
2015-01-01
Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...
DESIGN OF A FAST CHROMATICITY JUMP IN RHIC
International Nuclear Information System (INIS)
MONTAG, C.; KEWISCH, J.; BRUNO, D.; GANETIS, G.; LOUIE, W.
2003-01-01
During transition crossing in the .Relativistic Heavy Ion Collider (RHIC), chromaticities have to change sign. This sign change is partially accomplished by the γ t quadrupole jump; however, the resulting chromaticity jump is only Δξ x = 2.1 in the horizontal and Δξ y = 2.4 in the vertical plane. To increase the jump height, a dedicated chromaticity jump scheme has been designed, consisting of fast power supplies connected to six sextupoles per ring, which is capable of providing a chromaticity jump of Δξ = 6
Biomechanical Analysis of the Jump Shot in Basketball
Directory of Open Access Journals (Sweden)
Struzik Artur
2014-10-01
Full Text Available Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player’s jumping ability
Rantalainen, T; Hesketh, K D; Rodda, C; Duckham, R L
2018-06-16
Jump tests assess lower body power production capacity, and can be used to evaluate athletic ability and development during growth. Wearable inertial measurement units (IMU) seem to offer a feasible alternative to laboratory-based equipment for jump height assessments. Concurrent validity of these devices for jump height assessments has only been established in adults. Therefore, the purpose of this study was to evaluate the concurrent validity of IMU-based jump height estimate compared to contact mat-based jump height estimate in adolescents. Ninety-five adolescents (10-13 years-of-age; girls N=41, height = 154 (SD 9) cm, weight = 44 (11) kg; boys N=54, height=156 (10) cm, weight = 46 (13) kg) completed three counter-movement jumps for maximal jump height on a contact mat. Inertial recordings (accelerations, rotations) were concurrently recorded with a hip-worn IMU (sampling at 256 Hz). Jump height was evaluated based on flight time. The mean IMU-derived jump height was 27.1 (SD 3.8) cm, and the corresponding mean jump-mat-derived value was 21.5 (3.4) cm. While a significant 26% mean difference was observed between the methods (5.5 [95% limits of agreement 2.2 to 8.9] cm, p = 0.006), the correspondence between methods was excellent (ICC = 0.89). The difference between methods was weakly positively associated with jump height (r = 0.28, P = 0.007). Take-off velocity derived jump height was also explored but produced only fair congruence. In conclusion, IMU-derived jump height exhibited excellent congruence to contact mat-based jump height and therefore presents a feasible alternative for jump height assessments in adolescents. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
A Jump Diffusion Model for Volatility and Duration
DEFF Research Database (Denmark)
Wei, Wei; Pelletier, Denis
by the market microstructure theory. Traditional measures of volatility do not utilize durations. I adopt a jump diffusion process to model the persistence of intraday volatility and conditional duration, and their interdependence. The jump component is disentangled from the continuous part of the price......, volatility and conditional duration process. I develop a MCMC algorithm for the inference of irregularly spaced multivariate process with jumps. The algorithm provides smoothed estimates of the latent variables such as spot volatility, jump times and jump sizes. I apply this model to IBM data and I find...... meaningful relationship between volatility and conditional duration. Also, jumps play an important role in the total variation, but the jump variation is smaller than traditional measures that use returns sampled at lower frequency....
Propulsion efficiency and imposed flow fields of a copepod jump
DEFF Research Database (Denmark)
Jiang, H.; Kiørboe, Thomas
2011-01-01
Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed...... the imposed flow fields and associated energetics of jumps by means of computational fluid dynamics simulations by modeling the copepod as a self-propelled body. The computational fluid dynamics simulation was validated by particle image velocimetry data. The flow field generated by a repositioning jump...... the flow structure. The flow field associated with an escape jump sequence also includes two dominant vortex structures: one leading wake vortex generated as a result of the first jump and one around the body, but between these two vortex structures is an elongated, long-lasting flow trail with flow...
Quantum-corrected plasmonic field analysis using a time domain PMCHWT integral equation
Uysal, Ismail E.; Ulku, H. Arda; Bagci, Hakan
2016-01-01
When two structures are within sub-nanometer distance of each other, quantum tunneling, i.e., electrons "jumping" from one structure to another, becomes relevant. Classical electromagnetic solvers do not directly account for this additional path
National Research Council Canada - National Science Library
Agarwal, G. S
2013-01-01
.... Focusing on applications of quantum optics, the textbook covers recent developments such as engineering of quantum states, quantum optics on a chip, nano-mechanical mirrors, quantum entanglement...
Bartmann, W; Métral, E; Möhl, D; Peggs, S
2008-01-01
The PS2, which is proposed as a replacement for the existing ~50-year old PS accelerator, is presently considered to be a normal conducting synchrotron with an injection kinetic energy of 4 GeV and a maximum energy of 50 GeV. One of the possible lattices (FODO option) foresees crossing of transition energy near 10 GeV. Since the phase-slip-factor $\\eta$ becomes very small near transition energy, many intensity dependent effects can take place in both longitudinal and transverse planes. The aim of the present paper is on the one hand to scale the gamma transition jump, used since 1973 in the PS, to the projected PS2 and on the other hand based on these results the analysis of the implementation and feasibility of a gamma transition jump scheme in a conventional FODO lattice.
Testing jumps via false discovery rate control.
Yen, Yu-Min
2013-01-01
Many recently developed nonparametric jump tests can be viewed as multiple hypothesis testing problems. For such multiple hypothesis tests, it is well known that controlling type I error often makes a large proportion of erroneous rejections, and such situation becomes even worse when the jump occurrence is a rare event. To obtain more reliable results, we aim to control the false discovery rate (FDR), an efficient compound error measure for erroneous rejections in multiple testing problems. We perform the test via the Barndorff-Nielsen and Shephard (BNS) test statistic, and control the FDR with the Benjamini and Hochberg (BH) procedure. We provide asymptotic results for the FDR control. From simulations, we examine relevant theoretical results and demonstrate the advantages of controlling the FDR. The hybrid approach is then applied to empirical analysis on two benchmark stock indices with high frequency data.
Testing jumps via false discovery rate control.
Directory of Open Access Journals (Sweden)
Yu-Min Yen
Full Text Available Many recently developed nonparametric jump tests can be viewed as multiple hypothesis testing problems. For such multiple hypothesis tests, it is well known that controlling type I error often makes a large proportion of erroneous rejections, and such situation becomes even worse when the jump occurrence is a rare event. To obtain more reliable results, we aim to control the false discovery rate (FDR, an efficient compound error measure for erroneous rejections in multiple testing problems. We perform the test via the Barndorff-Nielsen and Shephard (BNS test statistic, and control the FDR with the Benjamini and Hochberg (BH procedure. We provide asymptotic results for the FDR control. From simulations, we examine relevant theoretical results and demonstrate the advantages of controlling the FDR. The hybrid approach is then applied to empirical analysis on two benchmark stock indices with high frequency data.
Entropy jump across an inviscid shock wave
Salas, Manuel D.; Iollo, Angelo
1995-01-01
The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.
Price jumps on European stock markets
Czech Academy of Sciences Publication Activity Database
Hanousek, Jan; Kočenda, Evžen; Novotný, Jan
2014-01-01
Roč. 14, č. 1 (2014), s. 10-22 ISSN 2214-8450 R&D Projects: GA ČR(CZ) GAP403/11/0020; GA ČR(CZ) GBP402/12/G097 Grant - others:UK(CZ) UNCE 204005/2012 Institutional support: PRVOUK-P23 Keywords : stock markets * price jump indicators * non-parametric testing Subject RIV: AH - Economics
Take-off aerodynamics in ski jumping.
Virmavirta, M; Kivekäs, J; Komi, P V
2001-04-01
The effect of aerodynamic forces on the force-time characteristics of the simulated ski jumping take-off was examined in a wind tunnel. Vertical and horizontal ground reaction forces were recorded with a force plate installed under the wind tunnel floor. The jumpers performed take-offs in non-wind conditions and in various wind conditions (21-33 m s(-1)). EMGs of the important take-off muscles were recorded from one jumper. The dramatic decrease in take-off time found in all jumpers can be considered as the result of the influence of aerodynamic lift. The loss in impulse due to the shorter force production time with the same take-off force is compensated with the increase in lift force, resulting in a higher vertical velocity (V(v)) than is expected from the conventional calculation of V(v) from the force impulse. The wind conditions emphasized the explosiveness of the ski jumping take-off. The aerodynamic lift and drag forces which characterize the aerodynamic quality of the initial take-off position (static in-run position) varied widely even between the examined elite ski jumpers. According to the computer simulation these differences can decisively affect jumping distance. The proper utilization of the prevailing aerodynamic forces before and during take-off is a very important prerequisite for achieving a good flight position.
Hydraulic jumps in ''viscous'' accretion disks
International Nuclear Information System (INIS)
Michel, F.C.
1984-01-01
We propose that the dissipative process necessary for rapid accretion disk evolution is driven by hydraulic jump waves on the surface of the disk. These waves are excited by the asymmetric nature of the central rotator (e.g., neutron star magnetosphere) and spiral out into the disk to form a pattern corotating with the central object. Disk matter in turn is slowed slightly at each encounter with the jump and spirals inward. In this process, the disk is heated by true turbulence produced in the jumps. Additional effects, such as a systematic misalignment of the magnetic moment of the neutron star until it is nearly orthogonal, and systematic distortion of the magnetosphere in such a way as to form an even more asymmetric central ''paddle wheel'' may enhance the interaction with inflowing matter. The application to X-ray sources corresponds to the ''slow'' solutions of Ghosh and Lamb, and therefore to rms magnetic fields of about 4 x 10 10 gauss. Analogous phenomena have been proposed to act in the formation of galactic spiral structure
Sex Differences in Countermovement Jump Phase Characteristics
Directory of Open Access Journals (Sweden)
John J. McMahon
2017-01-01
Full Text Available The countermovement jump (CMJ is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH, reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79. Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power, 47%–54% (start of eccentric phase and 85%–100% (latter half of concentric phase, and 65%–87% (bottom of countermovement and initial concentric phase of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off.
Jump Squat is More Related to Sprinting and Jumping Abilities than Olympic Push Press.
Loturco, I; Kobal, R; Maldonado, T; Piazzi, A F; Bottino, A; Kitamura, K; Abad, C C C; Pereira, L A; Nakamura, F Y
2017-07-01
The aim of this study was to test the relationships between jump squat (JS) and Olympic push press (OPP) power outputs and performance in sprint, squat jump (SJ), countermovement jump (CMJ) and change of direction (COD) speed tests in elite soccer players. 27 athletes performed a maximum power load test to determine their bar mean propulsive power (MPP) and bar mean propulsive velocity (MPV) in the JS and OPP exercises. Magnitude-based inference was used to compare the exercises. The MPV was almost certainly higher in the OPP than in the JS. The MPP relative to body mass (MPP REL) was possibly higher in the OPP. Only the JS MPP REL presented very large correlations with linear speed ( r> 0.7, for speed in 5, 10, 20 and 30 m) and vertical jumping abilities ( r> 0.8, for SJ and CMJ), and moderate correlation with COD speed ( r= 0.45). Although significant (except for COD), the associations between OPP outcomes and field-based measurements (speed, SJ and CMJ) were all moderate, ranging from 0.40 to 0.48. In a group composed of elite soccer players, the JS exercise is more associated with jumping and sprinting abilities than the OPP. Longitudinal studies are needed to confirm if these strong relationships imply superior training effects in favor of the JS exercise. © Georg Thieme Verlag KG Stuttgart · New York.
Farr, W. M.; Mandel, I.; Stevens, D.
2015-01-01
Selection among alternative theoretical models given an observed dataset is an important challenge in many areas of physics and astronomy. Reversible-jump Markov chain Monte Carlo (RJMCMC) is an extremely powerful technique for performing Bayesian model selection, but it suffers from a fundamental difficulty and it requires jumps between model parameter spaces, but cannot efficiently explore both parameter spaces at once. Thus, a naive jump between parameter spaces is unlikely to be accepted in the Markov chain Monte Carlo (MCMC) algorithm and convergence is correspondingly slow. Here, we demonstrate an interpolation technique that uses samples from single-model MCMCs to propose intermodel jumps from an approximation to the single-model posterior of the target parameter space. The interpolation technique, based on a kD-tree data structure, is adaptive and efficient in modest dimensionality. We show that our technique leads to improved convergence over naive jumps in an RJMCMC, and compare it to other proposals in the literature to improve the convergence of RJMCMCs. We also demonstrate the use of the same interpolation technique as a way to construct efficient ‘global’ proposal distributions for single-model MCMCs without prior knowledge of the structure of the posterior distribution, and discuss improvements that permit the method to be used in higher dimensional spaces efficiently. PMID:26543580
Force generation and temperature-jump and length-jump tension transients in muscle fibers.
Davis, J S; Rodgers, M E
1995-01-01
Muscle tension rises with increasing temperature. The kinetics that govern the tension rise of maximally Ca(2+)-activated, skinned rabbit psoas fibers over a temperature range of 0-30 degrees C was characterized in laser temperature-jump experiments. The kinetic response is simple and can be readily interpreted in terms of a basic three-step mechanism of contraction, which includes a temperature-sensitive rapid preequilibrium(a) linked to a temperature-insensitive rate-limiting step and followed by a temperature-sensitive tension-generating step. These data and mechanism are compared and contrasted with the more complex length-jump Huxley-Simmons phases in which all states that generate tension or bear tension are perturbed. The rate of the Huxley-Simmons phase 4 is temperature sensitive at low temperatures but plateaus at high temperatures, indicating a change in rate-limiting step from a temperature-sensitive (phase 4a) to a temperature-insensitive reaction (phase 4b); the latter appears to correlate with the slow, temperature-insensitive temperature-jump relaxation. Phase 3 is absent in the temperature-jump, which excludes it from tension generation. We confirm that de novo tension generation occurs as an order-disorder transition during phase 2slow and the equivalent, temperature-sensitive temperature-jump relaxation. PMID:7612845
Clissold, Tracey L; Winwood, Paul W; Cronin, John B; De Souza, Mary Jane
2018-04-01
Jumps have been investigated as a stimulus for bone development; however, effects of instruction, jump type, and jump-landing techniques need investigation. This study sought to identify whether ground reaction forces (GRFs) for bilateral vertical jumps (countermovement jumps and drop jumps) with reactive jump-landings (ie, jumping immediately after initial jump-landing), with instruction and with instruction withdrawn, achieve magnitudes and rates of strain previously shown to improve bone mass among premenopausal women. Twenty-one women (Mean ± SD: 43.3 ± 5.9 y; 69.4 ± 9.6 kg; 167 ± 5.5 cm; 27.5 ± 8.7% body fat) performed a testing session 'with instruction' followed by a testing session performed 1 week later with 'instruction withdrawn.' The magnitudes (4.59 to 5.49 body weight [BW]) and rates of strain (263 to 359 BW·s -1 ) for the jump-landings, performed on an AMTI force plate, exceeded previously determined thresholds (>3 BWs and >43 BW·s -1 ). Interestingly, significantly larger peak resultant forces, (↑10%; P = .002) and peak rates of force development (↑20%; P jump-landing (postreactive jump). Small increases (ES = 0.22-0.42) in all landing forces were observed in the second jump-landing with 'instruction withdrawn.' These jumps represent a unique training stimulus for premenopausal women and achieve osteogenic thresholds thought prerequisite for bone growth.
Jump Shrug Height and Landing Forces Across Various Loads.
Suchomel, Timothy J; Taber, Christopher B; Wright, Glenn A
2016-01-01
The purpose of this study was to examine the effect that load has on the mechanics of the jump shrug. Fifteen track and field and club/intramural athletes (age 21.7 ± 1.3 y, height 180.9 ± 6.6 cm, body mass 84.7 ± 13.2 kg, 1-repetition-maximum (1RM) hang power clean 109.1 ± 17.2 kg) performed repetitions of the jump shrug at 30%, 45%, 65%, and 80% of their 1RM hang power clean. Jump height, peak landing force, and potential energy of the system at jump-shrug apex were compared between loads using a series of 1-way repeated-measures ANOVAs. Statistical differences in jump height (P .05). The greatest magnitudes of jump height, peak landing force, and potential energy of the system at the apex of the jump shrug occurred at 30% 1RM hang power clean and decreased as the external load increased from 45% to 80% 1RM hang power clean. Relationships between peak landing force and potential energy of the system at jump-shrug apex indicate that the landing forces produced during the jump shrug may be due to the landing strategy used by the athletes, especially at lighter loads. Practitioners may prescribe heavier loads during the jump-shrug exercise without viewing landing force as a potential limitation.
Jumping robots: a biomimetic solution to locomotion across rough terrain.
Armour, Rhodri; Paskins, Keith; Bowyer, Adrian; Vincent, Julian; Megill, William; Bomphrey, Richard
2007-09-01
This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection.
Neuromuscular function during drop jumps in young and elderly males.
Piirainen, Jarmo M; Linnamo, Vesa; Sippola, Niina; Avela, Janne
2012-12-01
The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves were measured during standing rest. Although in young the H-reflex response (Hmax/Mmax) was 6.5% higher during relaxed standing and 19.7% higher during drop jumps (H jump/M jump) than in the elderly group, these differences were not statistically significant. In drop jumps, the elderly subjects had lower jumping height (30.4%, p push-off force (18.0%, p push-off time (31.0% p push-off force (r = 0.833, p push-off time (r = -0.857, p < 0.01) in young but not in the elderly. Correlations between H-reflex response and jumping parameters in young may indicate different jumping and activation strategies in drop jumps. However, it does not fully explain age related differences in jumping performance, since age related differences in H-reflex activity were non-significant. Copyright © 2012 Elsevier Ltd. All rights reserved.
Ski jumping boots limit effective take-off in ski jumping.
Virmavirta, M; Komi, P V
2001-12-01
In this study, we measured the vertical and horizontal take-off forces, plantar pressures and activation patterns of four muscles (vastus lateralis, gluteus maximus, tibialis anterior, gastrocnemius) in 10 ski jumpers in simulated laboratory conditions when wearing either training shoes or ski jumping boots. We found significant differences in vertical (P boots condition resulted in a smaller displacement in the final position of the following joint angles: ankle angle (P knee angle (P boots condition, significantly more pressure was recorded under the heel (P knee and hip extensors when wearing jumping boots. We conclude that the stiffness of the structure of the jumping boots may result in a forward shift of pressure, thus limiting the effective vertical force. To avoid this pressure shift, the pattern of movement of simulated take-offs should be carefully controlled, particularly when wearing training shoes.
Jump Tails, Extreme Dependencies, and the Distribution of Stock Returns
DEFF Research Database (Denmark)
Bollerslev, Tim; Todorov, Viktor
We provide a new framework for estimating the systematic and idiosyncratic jump tail risks in financial asset prices. The theory underlying our estimates are based on in-fill asymptotic arguments for directly identifying the systematic and idiosyncratic jumps, together with conventional long...... market portfolio, we find that the distributions of the systematic and idiosyncratic jumps are both generally heavy-tailed and not necessarily symmetric. Our estimates also point to the existence of strong dependencies between the market-wide jumps and the corresponding systematic jump tails for all...... of the stocks in the sample. We also show how the jump tail dependencies deduced from the high-frequency data together with the day-to-day temporal variation in the volatility are able to explain the “extreme” dependencies vis-a-vis the market portfolio....
Influence of magnetic history on flux jump fields
International Nuclear Information System (INIS)
Sosnowski, J.
1986-01-01
A formalism describing the fields at which flux jumps occur in hard superconductors has been confirmed by the description of an experimentally observed shift of flux jump fields in the second hysteresis loop of a Nb 3 Al superconducting sample. By fitting the theoretical model to experimental data, values of the proportionality parameter between the stability limit and the flux jump field, the first stability limit, and the first penetration field have been estimated
Dynamics and stability of directional jumps in the desert locust.
Gvirsman, Omer; Kosa, Gabor; Ayali, Amir
2016-01-01
Locusts are known for their ability to jump large distances to avoid predation. The jump also serves to launch the adult locust into the air in order to initiate flight. Various aspects of this important behavior have been studied extensively, from muscle physiology and biomechanics, to the energy storage systems involved in powering the jump, and more. Less well understood are the mechanisms participating in control of the jump trajectory. Here we utilise video monitoring and careful analysis of experimental directional jumps by adult desert locusts, together with dynamic computer simulation, in order to understand how the locusts control the direction and elevation of the jump, the residual angular velocities resulting from the jump and the timing of flapping-flight initiation. Our study confirms and expands early findings regarding the instrumental role of the initial body position and orientation. Both real-jump video analysis and simulations based on our expanded dynamical model demonstrate that the initial body coordinates of position (relative to the hind-legs ground-contact points) are dominant in predicting the jumps' azimuth and elevation angles. We also report a strong linear correlation between the jumps' pitch-angular-velocity and flight initiation timing, such that head downwards rotations lead to earlier wing opening. In addition to offering important insights into the bio-mechanical principles of locust jumping and flight initiation, the findings from this study will be used in designing future prototypes of a bio-inspired miniature jumping robot that will be employed in animal behaviour studies and environmental monitoring applications.
Biomechanics research in ski jumping, 1991-2006.
Schwameder, Hermann
2008-01-01
In this paper, I review biomechanics research in ski jumping with a specific focus on publications presented between 1991 and 2006 on performance enhancement, limiting factors of the take-off, specific training and conditioning, aerodynamics, and safety. The first section presents a brief description of ski jumping phases (in-run, take-off, early flight, stable flight, and landing) regarding the biomechanical and functional fundamentals. The most important and frequently used biomechanical methods in ski jumping (kinematics, ground reaction force analyses, muscle activation patterns, aerodynamics) are summarized in the second section. The third section focuses on ski jumping articles and research findings published after the establishment of the V-technique in 1991, as the introduction of this technique has had a major influence on performance enhancement, ski jumping regulations, and the construction of hill profiles. The final section proposes topics for future research in the biomechanics of ski jumping, including: take-off and early flight and the relative roles of vertical velocity and forward somersaulting angular momentum; optimal jumping patterns utilizing the capabilities of individual athletes; development of kinematic and kinetic feedback systems for hill jumps; comparisons of simulated and hill jumps; effect of equipment modifications on performance and safety enhancement.
Jump phenomena. [large amplitude responses of nonlinear systems
Reiss, E. L.
1980-01-01
The paper considers jump phenomena composed of large amplitude responses of nonlinear systems caused by small amplitude disturbances. Physical problems where large jumps in the solution amplitude are important features of the response are described, including snap buckling of elastic shells, chemical reactions leading to combustion and explosion, and long-term climatic changes of the earth's atmosphere. A new method of rational functions was then developed which consists of representing the solutions of the jump problems as rational functions of the small disturbance parameter; this method can solve jump problems explicitly.
Effect of drop jump technique on the reactive strength index.
Struzik, Artur; Juras, Grzegorz; Pietraszewski, Bogdan; Rokita, Andrzej
2016-09-01
The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p jump technique that is commonly performed by basketball players.
Impact of wave phase jumps on stochastic heating
International Nuclear Information System (INIS)
Zasenko, V.I.; Zagorodny, A.G.; Cherniak, O.M.
2016-01-01
Interaction of charged particles with fields of random waves brings about known effects of stochastic acceleration and heating. Jumps of wave phases can increase the intensity of these processes substantially. Numerical simulation of particle heating and acceleration by waves with regular phases, waves with jumping phase and stochastic electric field impulses is performed. Comparison of the results shows that to some extent an impact of phase jumps is similar to the action of separate field impulses. Jumps of phase not only increase the intensity of resonant particle heating but involves in this process non-resonant particles from a wide range of initial velocities
Jump Testing and the Speed of Market Adjustment
DEFF Research Database (Denmark)
Rasmussen, Torben B.
Asymptotic properties of jump tests rely on the property that any jump occurs within a single time interval no matter what the observation frequency is. Market microstructure effects in relation to news-induced revaluation of the underlying variable is likely to make this an unrealistic assumption...... for high-frequency transaction data. To capture these microstructure effects, this paper suggests a model in which market prices adjust gradually to jumps in the underlying effcient price. A case study illustrates the empirical relevance of the model, and the performance of different jump tests...
Development of a Minimally Actuated Jumping-Rolling Robot
Directory of Open Access Journals (Sweden)
Thanhtam Ho
2015-04-01
Full Text Available This paper presents development of a hybrid mobile robot in order to take advantage of both rolling and jumping locomotion on the ground. According to the unique design of the mechanism, the robot is able to execute both jumping and rolling skilfully by using only one DC motor. Changing the centre of gravity enables rolling of the robot and storage of energy is utilized for jumping. Mechanism design and control logic are validated by computer simulation. Simulation results show that the robot can jump nearly 1.3 times its diameter and roll at the speed of 3.3 times its diameter per second.
Effect of drop jump technique on the reactive strength index
Directory of Open Access Journals (Sweden)
Struzik Artur
2016-09-01
Full Text Available The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI for countermovement drop jumps (CDJs and bounce drop jumps (BDJs. The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05 between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05 than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05 than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.
Quantum Erasure: Quantum Interference Revisited
Walborn, Stephen P.; Cunha, Marcelo O. Terra; Pádua, Sebastião; Monken, Carlos H.
2005-01-01
Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.
International Nuclear Information System (INIS)
Polat, Recep; İçelli, Orhan; Yalçın, Zeynel; Pesen, Erhan; Orak, Salim
2013-01-01
Highlights: ► Mass attenuation coefficients, jump factor and jump ratio for lanthanide elements are obtained. ► The method used in this experiment is combined both transmission and scattering geometry. ► Secondary gamma rays energy is 59.5 keV. ► Experimental values of jump factor and jump ratio for K shell are new. ► The experimental values are in good agreement with those calculated theoretically. - Abstract: 59.5 keV gamma rays scattered by an aluminum foil have been used as a radiation source to measure the absorption jump factor and jump ratios for absorbers Ce, Pr, Nd, Sm, Eu and Tb. The theoretical and experimental values are compared with the corresponding ones in the literature
Locally Perturbed Random Walks with Unbounded Jumps
Paulin, Daniel; Szász, Domokos
2010-01-01
In \\cite{SzT}, D. Sz\\'asz and A. Telcs have shown that for the diffusively scaled, simple symmetric random walk, weak convergence to the Brownian motion holds even in the case of local impurities if $d \\ge 2$. The extension of their result to finite range random walks is straightforward. Here, however, we are interested in the situation when the random walk has unbounded range. Concretely we generalize the statement of \\cite{SzT} to unbounded random walks whose jump distribution belongs to th...
Multiobjective Optimization Methodology A Jumping Gene Approach
Tang, KS
2012-01-01
Complex design problems are often governed by a number of performance merits. These markers gauge how good the design is going to be, but can conflict with the performance requirements that must be met. The challenge is reconciling these two requirements. This book introduces a newly developed jumping gene algorithm, designed to address the multi-functional objectives problem and supplies a viably adequate solution in speed. The text presents various multi-objective optimization techniques and provides the technical know-how for obtaining trade-off solutions between solution spread and converg
Determinant Factors of the Squat Jump in Sprinting and Jumping Athletes
Directory of Open Access Journals (Sweden)
González-Badillo Juan José
2017-08-01
Full Text Available The aim of this study was to assess the relationship between strength variables and maximum velocity (Vmax in the squat jump (SJ in sprinting and jumping athletes. Thirty-two sprinting and jumping athletes of national level (25.4 ± 4.5 years; 79.4 ± 6.9 kg and 180.4 ± 6.0 cm participated in the study. Vmax in the SJ showed significant relationships with peak force 1 (PF1 (r = 0.82, p ≤ 0.001, peak force 2 (PF2 (r = 0.68, p ≤ 0.001, PF2 by controlling for PF1 (r = 0.30, non-significant, the maximum rate of force development at peak force 1 (RFDmax1 (r = 0.62, p ≤ 0.001, mean RFD 1 (RFDmean1 (r = 0.48, p ≤ 0.01, mean RFD 2 (RFDmean2 (r = 0.70, p ≤ 0.001, force at RFDmax1 (r = 0.36, p ≤ 0.05, force at RFDmax2 (r = 0.83, p ≤ 0.001 and force at RFDmax2 by controlling for PF1 (r = 0.40, p ≤ 0.05. However, Vmax in the SJ was associated negatively with the ratio PF2/PF1 (r = -0.54, p ≤ 0.01, time at peak force 2 (Tp2 (r = -0.64, p ≤ 0.001 and maximum rate of force development at peak force 2 (RFDmax2 (r = -0.71, p ≤ 0.001. These findings indicate that the peak force achieved at the beginning of the movement (PF1 is the main predictor of performance in jumping, although the RFDmax values and the ratio PF2/PF1 are also variables to be taken into account when analyzing the determinant factors of vertical jumping.
Adaptive resummation of Markovian quantum dynamics
International Nuclear Information System (INIS)
Lucas, Felix
2014-01-01
In this thesis we derive a highly convergent, nonperturbative expansion of Markovian open quantum dynamics. It is based on a splitting of the incoherent dynamics into periods of continuous evolution and abrupt jumps and attains its favorable convergence properties from an adaptive resummation of this so-called jump expansion. By means of the long-standing problems of spatial particle detection and Landau-Zener tunneling in the presence of dephasing, we show that this adaptive resummation technique facilitates new highly accurate analytic approximations of Markovian open systems. The open Landau-Zener model leads us to propose an efficient and robust incoherent control technique for the isomerization reaction of the visual pigment protein rhodopsin. Besides leading to approximate analytic descriptions of Markovian open quantum dynamics, the adaptive resummation of the jump expansion implies an efficient numerical simulation method. We spell out the corresponding numerical algorithm by means of Monte Carlo integration of the relevant terms in the jump expansion and demonstrate it in a set of paradigmatic open quantum systems.
Energy Technology Data Exchange (ETDEWEB)
Hui, Ning-Ju [Department of Applied Physics, Xi' an University of Technology, Xi' an 710054 (China); Xu, Yang-Yang; Wang, Jicheng; Zhang, Yixin [Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, School of Science, Jiangnan University, Wuxi 214122 (China); Hu, Zheng-Da, E-mail: huyuanda1112@jiangnan.edu.cn [Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, School of Science, Jiangnan University, Wuxi 214122 (China)
2017-04-01
We investigate the properties of geometric quantum coherence in the XY spin-1/2 chain with staggered Dzyaloshinsky-Moriya interaction via the quantum renormalization-group approach. It is shown that the geometric quantum coherence and its coherence susceptibility are effective to detect the quantum phase transition. In the thermodynamic limit, the geometric quantum coherence exhibits a sudden jump. The coherence susceptibilities versus the anisotropy parameter and the Dzyaloshinsky-Moriya interaction are infinite and vanishing, respectively, illustrating the distinct roles of the anisotropy parameter and the Dzyaloshinsky-Moriya interaction in quantum phase transition. Moreover, we also explore the finite-size scaling behaviors of the coherence susceptibilities. For a finite-size chain, the coherence susceptibility versus the phase-transition parameter is always maximal at the critical point, indicating the dramatic quantum fluctuation. Besides, we show that the correlation length can be revealed by the scaling exponent for the coherence susceptibility versus the Dzyaloshinsky-Moriya interaction.
Variability of Plyometric and Ballistic Exercise Technique Maintains Jump Performance.
Chandler, Phillip T; Greig, Matthew; Comfort, Paul; McMahon, John J
2018-06-01
Chandler, PT, Greig, M, Comfort, P, and McMahon, JJ. Variability of plyometric and ballistic exercise technique maintains jump performance. J Strength Cond Res 32(6): 1571-1582, 2018-The aim of this study was to investigate changes in vertical jump technique over the course of a training session. Twelve plyometric and ballistic exercise-trained male athletes (age = 23.4 ± 4.6 years, body mass = 78.7 ± 18.8 kg, height = 177.1 ± 9.0 cm) performed 3 sets of 10 repetitions of drop jump (DJ), rebound jump (RJ) and squat jump (SJ). Each exercise was analyzed from touchdown to peak joint flexion and peak joint flexion to take-off. Squat jump was analyzed from peak joint flexion to take-off only. Jump height, flexion and extension time and range of motion, and instantaneous angles of the ankle, knee, and hip joints were measured. Separate 1-way repeated analyses of variance compared vertical jump technique across exercise sets and repetitions. Exercise set analysis found that SJ had lower results than DJ and RJ for the angle at peak joint flexion for the hip, knee, and ankle joints and take-off angle of the hip joint. Exercise repetition analysis found that the ankle joint had variable differences for the angle at take-off, flexion, and extension time for RJ. The knee joint had variable differences for flexion time for DJ and angle at take-off and touchdown for RJ. There was no difference in jump height. Variation in measured parameters across repetitions highlights variable technique across plyometric and ballistic exercises. This did not affect jump performance, but likely maintained jump performance by overcoming constraints (e.g., level of rate coding).
CAPTURE OF TROJANS BY JUMPING JUPITER
International Nuclear Information System (INIS)
Nesvorný, David; Vokrouhlický, David; Morbidelli, Alessandro
2013-01-01
Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ∼5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) × 10 –7 for each particle in the original transplanetary disk, implying that the disk contained (3-4) × 10 7 planetesimals with absolute magnitude H disk ∼ 14-28 M Earth , is consistent with the mass deduced from recent dynamical simulations of the planetary instability.
The world price of jump and volatility risk
Driessen, J.; Maenhout, P.
2006-01-01
Jump and volatility risk are important for understanding equity returns, option pricing and asset allocation. This paper is the first to study international integration of markets for jump and volatility risk, using data on index options for each of the three main global markets: US S&P 500 index
Asymptotic inference for jump diffusions with state-dependent intensity
Becheri, Gaia; Drost, Feico; Werker, Bas
2016-01-01
We establish the local asymptotic normality property for a class of ergodic parametric jump-diffusion processes with state-dependent intensity and known volatility function sampled at high frequency. We prove that the inference problem about the drift and jump parameters is adaptive with respect to
Long multiplication by instruction sequences with backward jump instructions
Bergstra, J.A.; Middelburg, C.A.
2013-01-01
For each function on bit strings, its restriction to bit strings of any given length can be computed by a finite instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. Backward jump instructions
Knee Muscular Control During Jump Landing in Multidirections.
Sinsurin, Komsak; Vachalathiti, Roongtiwa; Jalayondeja, Wattana; Limroongreungrat, Weerawat
2016-06-01
Jump landing is a complex movement in sports. While competing and practicing, athletes frequently perform multi-planar jump landing. Anticipatory muscle activity could influence the amount of knee flexion and prepare the knee for dynamic weight bearing such as landing tasks. The aim of the present study was to examine knee muscle function and knee flexion excursion as athletes naturally performed multi-direction jump landing. Eighteen male athletes performed the jump-landing test in four directions: forward (0°), 30° diagonal, 60° diagonal, and lateral (90°). Muscles tested were vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), and biceps femoris (BF). A Vicon(TM) 612 workstation collected the kinematic data. An electromyography was synchronized with the Vicon(TM) Motion system to quantify dynamic muscle function. Repeated measure ANOVA was used to analyze the data. Jump-landing direction significantly influenced (P jump landing. A higher risk of knee injury might occur during lateral jump landing than forward and diagonal directions. Athletes should have more practice in jump landing in lateral direction to avoid injury. Landing technique with high knee flexion in multi-directions should be taught to jumpers for knee injury prevention.
Immediate Effects of Different Trunk Exercise Programs on Jump Performance.
Imai, A; Kaneoka, K; Okubo, Y; Shiraki, H
2016-03-01
The aim of this study was to investigate the immediate effects of trunk stabilization exercise (SE) and conventional trunk exercise (CE) programs on jump performance. 13 adolescent male soccer players performed 2 kinds of jump testing before and immediate after 3 experimental conditions: SE, CE, and non-exercise (NE). The SE program consisted of the elbow-toe, hand-knee, and back bridge, and the CE program consisted of the sit-up, sit-up with trunk rotation and back extension. Testing of a countermovement jump (CMJ) and rebound jump (RJ) were performed to assess jump performance. Jump height of the CMJ and RJ-index, contact time, and jump height of the RJ were analyzed. The RJ index was improved significantly only after SE (p=0.017). However, contact time and jump height did not improve significantly in the SE condition. Moreover, no significant interaction or main effects of time or group were observed in the CMJ. Consequently, this study showed the different immediate effect on the RJ between the SE and CE, and suggested the possibility that the SE used in this study is useful as a warm-up program to improve the explosive movements. © Georg Thieme Verlag KG Stuttgart · New York.
A Jump-Diffusion Model with Stochastic Volatility and Durations
DEFF Research Database (Denmark)
Wei, Wei; Pelletier, Denis
jumps in two ways: as exogenous sampling intervals, and through the interaction with volatility. We adopt a bivariate Ornstein-Ulenbeck process to model intraday volatility and conditional duration. We develop a MCMC algorithm for the inference on irregularly spaced multivariate processes with jumps...
Dynamics of force and muscle stimulation in human vertical jumping
Bobbert, M.F.; van Zandwijk, J.P.
1999-01-01
PURPOSE: The purpose of this study was to gain insight into the importance of stimulation dynamics for force development in human vertical jumping. METHODS: Maximum height squat jumps were performed by 21 male subjects. As a measure of signal dynamics, rise time (RT) was used, i.e., the time taken
Role of the hamstrings in human vertical jumping
Bobbert, Maarten F.
1996-01-01
In some human subjects performing maximum-height squat jumps, the EMG-pattern of semitendinosus is bi-phasic and that of biceps femoris is mono-phasic. The purpose of this study was to investigate the roles of biceps femoris and semitendinosus in squat jumping, and to explain why they are different.
Forces exerted by jumping children: A pilot study
Moes, C.C.M.; Bakker, H.E.
1998-01-01
This article reports on a pilot study of the loads exerted vertically by children when jumping. The subjects of the study were 17 children, aged from two to twelve years. Measurements were made using video recordings and a force-plate. The influence of the stiffness of the base and of jumping with
On Pathos Adjacency Cut Vertex Jump Graph of a Tree
Nagesh.H.M; R.Chandrasekhar
2014-01-01
In this paper the concept of pathos adjacency cut vertex jump graph PJC(T) of a tree T is introduced. We also present a characterization of graphs whose pathos adjacency cut vertex jump graphs are planar, outerplanar, minimally non-outerplanar, Eulerian and Hamiltonian.
Teaching Jump Rope to Children with Visual Impairments
Lieberman, Lauren J.; Schedlin, Haley; Pierce, Tristan
2009-01-01
This article presents strategies for jumping rope for children with visual impairments. Giving choices related to the types of rope and the use of mats is important. In addition, using appropriate instructional strategies and modifications will make jumping rope a skill that the children will enjoy and will lead to their involvement in other…
Haynes, Tom; Bishop, Chris; Antrobus, Mark; Brazier, Jon
2018-03-27
This is the first study to independently assess the concurrent validity and reliability of the My Jump 2 app for measuring drop jump performance. It is also the first to evaluate the app's ability to measure the reactive strength index (RSI). Fourteen male sport science students (age: 29.5 ± 9.9 years) performed three drop jumps from 20 cm and 40 cm (totalling 84 jumps), assessed via a force platform and the My Jump 2 app. Reported metrics included reactive strength index, jump height, ground contact time, and mean power. Measurements from both devices were compared using the intraclass correlation coefficient (ICC), Pearson product moment correlation coefficient (r), Cronbach's alpha (α), coefficient of variation (CV) and BlandAltman plots. Near perfect agreement was seen between devices at 20 cm for RSI (ICC = 0.95) and contact time (ICC = 0.99) and at 40 cm for RSI (ICC = 0.98), jump height (ICC = 0.96) and contact time (ICC = 0.92); with very strong agreement seen at 20 cm for jump height (ICC = 0.80). In comparison with the force plate the app showed good validity for RSI (20 cm: r = 0.94; 40 cm; r = 0.97), jump height (20 cm: r = 0.80; 40 cm; r = 0.96) and contact time (20 cm = 0.96; 40 cm; r = 0.98). The results of the present study show that the My Jump 2 app is a valid and reliable tool for assessing drop jump performance.
Directory of Open Access Journals (Sweden)
Mandic Radivoj
2016-09-01
Full Text Available The aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.
Mandic, Radivoj; Knezevic, Olivera M; Mirkov, Dragan M; Jaric, Slobodan
2016-09-01
The aim of the present study was to explore the control strategy of maximum countermovement jumps regarding the preferred countermovement depth preceding the concentric jump phase. Elite basketball players and physically active non-athletes were tested on the jumps performed with and without an arm swing, while the countermovement depth was varied within the interval of almost 30 cm around its preferred value. The results consistently revealed 5.1-11.2 cm smaller countermovement depth than the optimum one, but the same difference was more prominent in non-athletes. In addition, although the same differences revealed a marked effect on the recorded force and power output, they reduced jump height for only 0.1-1.2 cm. Therefore, the studied control strategy may not be based solely on the countermovement depth that maximizes jump height. In addition, the comparison of the two groups does not support the concept of a dual-task strategy based on the trade-off between maximizing jump height and minimizing the jumping quickness that should be more prominent in the athletes that routinely need to jump quickly. Further research could explore whether the observed phenomenon is based on other optimization principles, such as the minimization of effort and energy expenditure. Nevertheless, future routine testing procedures should take into account that the control strategy of maximum countermovement jumps is not fully based on maximizing the jump height, while the countermovement depth markedly confound the relationship between the jump height and the assessed force and power output of leg muscles.
Option Valuation with Observable Volatility and Jump Dynamics
DEFF Research Database (Denmark)
Christoffersen, Peter; Feunou, Bruno; Jeon, Yoontae
Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...... for straightforward filtering and estimation of the model. Our model belongs to the affine class enabling us to derive the conditional characteristic function so that option values can be computed rapidly without simulation. When estimated on S&P500 index options and returns the new model performs well compared...
Nonstandard jump functions for radically symmetric shock waves
International Nuclear Information System (INIS)
Baty, Roy S.; Tucker, Don H.; Stanescu, Dan
2008-01-01
Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function.
Study of brittle crack jump rate using acoustic emission method
International Nuclear Information System (INIS)
Yasnij, P.V.; Pokrovskij, V.V.; Strizhalo, V.A.; Dobrovol'skij, Yu.V.
1987-01-01
A new peocedure is elaborated to detect brittle jumps of small length (0.1...5mm) occuring both inside the specimen and along the crack front under static and cyclic loading using the phenomena of acoustic emission (AE). Recording of the crack start and stop moments with an AE sensor as well as evaluation of the brittle crack jump length by the after-failure specimen fracture make it possible to find the mean crack propagation rate. Experimental dependences are obtained for the crack propagation rate with a brittle crack jump in steel 15Kh2MFA (σ B =1157 MPa, σ 0.2 =100 MPa) at 293 K and under cyclic loading as a function of the jump length and also as a function of the critical stress intensity factor K jc i corresponding to the crack jump
Approaching stationarity: competition between long jumps and long waiting times
International Nuclear Information System (INIS)
Dybiec, Bartłomiej
2010-01-01
Within the continuous-time random walk (CTRW) scenarios, properties of the overall motion are determined by the waiting time and the jump length distributions. In the decoupled case, with power-law distributed waiting times and jump lengths, the CTRW scenario is asymptotically described by the double (space and time) fractional Fokker–Planck equation. Properties of a system described by such an equation are determined by the subdiffusion parameter and the jump length exponent. Nevertheless, the stationary state is determined solely by the jump length distribution and the potential. The waiting time distribution determines only the rate of convergence to the stationary state. Here, we inspect the competition between long waiting times and long jumps and how this competition is reflected in the way in which a stationary state is reached. In particular, we show that the distance between a time-dependent and a stationary solution changes in time as a double power law
The hydraulic jump and ripples in liquid helium
International Nuclear Information System (INIS)
Rolley, E.; Guthmann, C.; Pettersen, M.S.
2007-01-01
We have studied the characteristics of the circular hydraulic jump using liquid helium. Surprisingly, the radius of the jump does not change at the superfluid transition. We think that the flow is still dissipative below the lambda point because the velocity exceeds the critical one. The jump radius R j is compared with various models. In our parameter range, we find that the jump can be treated as a shock, and that capillary effects are important. Below the superfluid transition, we observed a standing capillary wave between the impact of the jet and the jump. Assuming that the superfluid flow can be described with an effective viscosity, we calculate the wave vector and thus obtain the value of the liquid thickness, which is in reasonable agreement with predictions. However, the spatial variation of the wave amplitude depends much more strongly on temperature than we calculate
Ballistic Jumping Drops on Superhydrophobic Surfaces via Electrostatic Manipulation.
Li, Ning; Wu, Lei; Yu, Cunlong; Dai, Haoyu; Wang, Ting; Dong, Zhichao; Jiang, Lei
2018-02-01
The ballistic ejection of liquid drops by electrostatic manipulating has both fundamental and practical implications, from raindrops in thunderclouds to self-cleaning, anti-icing, condensation, and heat transfer enhancements. In this paper, the ballistic jumping behavior of liquid drops from a superhydrophobic surface is investigated. Powered by the repulsion of the same kind of charges, water drops can jump from the surface. The electrostatic acting time for the jumping of a microliter supercooled drop only takes several milliseconds, even shorter than the time for icing. In addition, one can control the ballistic jumping direction precisely by the relative position above the electrostatic field. The approach offers a facile method that can be used to manipulate the ballistic drop jumping via an electrostatic field, opening the possibility of energy efficient drop detaching techniques in various applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Dynamics and stability of directional jumps in the desert locust
Directory of Open Access Journals (Sweden)
Omer Gvirsman
2016-09-01
Full Text Available Locusts are known for their ability to jump large distances to avoid predation. The jump also serves to launch the adult locust into the air in order to initiate flight. Various aspects of this important behavior have been studied extensively, from muscle physiology and biomechanics, to the energy storage systems involved in powering the jump, and more. Less well understood are the mechanisms participating in control of the jump trajectory. Here we utilise video monitoring and careful analysis of experimental directional jumps by adult desert locusts, together with dynamic computer simulation, in order to understand how the locusts control the direction and elevation of the jump, the residual angular velocities resulting from the jump and the timing of flapping-flight initiation. Our study confirms and expands early findings regarding the instrumental role of the initial body position and orientation. Both real-jump video analysis and simulations based on our expanded dynamical model demonstrate that the initial body coordinates of position (relative to the hind-legs ground-contact points are dominant in predicting the jumps’ azimuth and elevation angles. We also report a strong linear correlation between the jumps’ pitch-angular-velocity and flight initiation timing, such that head downwards rotations lead to earlier wing opening. In addition to offering important insights into the bio-mechanical principles of locust jumping and flight initiation, the findings from this study will be used in designing future prototypes of a bio-inspired miniature jumping robot that will be employed in animal behaviour studies and environmental monitoring applications.
Effects of Isometric Scaling on Vertical Jumping Performance
Bobbert, Maarten F.
2013-01-01
Jump height, defined as vertical displacement in the airborne phase, depends on vertical takeoff velocity. For centuries, researchers have speculated on how jump height is affected by body size and many have adhered to what has come to be known as Borelli’s law, which states that jump height does not depend on body size per se. The underlying assumption is that the amount of work produced per kg body mass during the push-off is independent of size. However, if a big body is isometrically downscaled to a small body, the latter requires higher joint angular velocities to achieve a given takeoff velocity and work production will be more impaired by the force-velocity relationship of muscle. In the present study, the effects of pure isometric scaling on vertical jumping performance were investigated using a biologically realistic model of the human musculoskeletal system. The input of the model, muscle stimulation over time, was optimized using jump height as criterion. It was found that when the human model was miniaturized to the size of a mouse lemur, with a mass of about one-thousandth that of a human, jump height dropped from 40 cm to only 6 cm, mainly because of the force-velocity relationship. In reality, mouse lemurs achieve jump heights of about 33 cm. By implication, the unfavourable effects of the small body size of mouse lemurs on jumping performance must be counteracted by favourable effects of morphological and physiological adaptations. The same holds true for other small jumping animals. The simulations for the first time expose and explain the sheer magnitude of the isolated effects of isometric downscaling on jumping performance, to be counteracted by morphological and physiological adaptations. PMID:23936494
Effects of isometric scaling on vertical jumping performance.
Directory of Open Access Journals (Sweden)
Maarten F Bobbert
Full Text Available Jump height, defined as vertical displacement in the airborne phase, depends on vertical takeoff velocity. For centuries, researchers have speculated on how jump height is affected by body size and many have adhered to what has come to be known as Borelli's law, which states that jump height does not depend on body size per se. The underlying assumption is that the amount of work produced per kg body mass during the push-off is independent of size. However, if a big body is isometrically downscaled to a small body, the latter requires higher joint angular velocities to achieve a given takeoff velocity and work production will be more impaired by the force-velocity relationship of muscle. In the present study, the effects of pure isometric scaling on vertical jumping performance were investigated using a biologically realistic model of the human musculoskeletal system. The input of the model, muscle stimulation over time, was optimized using jump height as criterion. It was found that when the human model was miniaturized to the size of a mouse lemur, with a mass of about one-thousandth that of a human, jump height dropped from 40 cm to only 6 cm, mainly because of the force-velocity relationship. In reality, mouse lemurs achieve jump heights of about 33 cm. By implication, the unfavourable effects of the small body size of mouse lemurs on jumping performance must be counteracted by favourable effects of morphological and physiological adaptations. The same holds true for other small jumping animals. The simulations for the first time expose and explain the sheer magnitude of the isolated effects of isometric downscaling on jumping performance, to be counteracted by morphological and physiological adaptations.
International Nuclear Information System (INIS)
Kaçal, M.R.
2014-01-01
Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring L 3 -subshell absorption jump ratios, r L 3 and jump factors, J L 3 for high Z elements. Jump factors and jump ratios for these elements have been determined by measuring L 3 subshell fluorescence parameters such as L 3 subshell X-ray production cross section σ L 3 , L 3 subshell fluorescence yield, ω L 3 , total L 3 subshell and higher subshells photoionization cross section σ L T . Measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation experimental geometry. Measured values for jump factors and jump ratios have been compared with theoretically calculated and other experimental values. - Highlights: • This paper regards L 3 subshell absorption jump ratios and jump factors using the EDXRF method. • These parameters were measured using a new method. • This method is more useful than other methods which require much effort. • Results are in good agreement with theoretical and experimental values
National Research Council Canada - National Science Library
Agarwal, G. S
2013-01-01
..., quantum metrology, spin squeezing, control of decoherence and many other key topics. Readers are guided through the principles of quantum optics and their uses in a wide variety of areas including quantum information science and quantum mechanics...
STABILITY OF LINEAR SYSTEMS WITH MARKOVIAN JUMPS
Directory of Open Access Journals (Sweden)
Jorge Enrique Mayta Guillermo
2016-12-01
Full Text Available In this work we will analyze the stability of linear systems governed by a Markov chain, this family is known in the specialized literature as linear systems with Markov jumps or by its acronyms in English MJLS as it is denoted in [1]. Linear systems governed by a Markov chain are dynamic systems with abrupt changes. We give some denitions of stability for the MJLS system, where these types of stability are equivalent as long as the state space of the Markov chain is nite. Finally we present a theorem that characterizes the stochastic stability by means of an equation of the Lyapunov type. The result is a generalization of a theorem in classical theory.
Seismic tomography with the reversible jump algorithm
Bodin, Thomas; Sambridge, Malcolm
2009-09-01
The reversible jump algorithm is a statistical method for Bayesian inference with a variable number of unknowns. Here, we apply this method to the seismic tomography problem. The approach lets us consider the issue of model parametrization (i.e. the way of discretizing the velocity field) as part of the inversion process. The model is parametrized using Voronoi cells with mobile geometry and number. The size, position and shape of the cells defining the velocity model are directly determined by the data. The inverse problem is tackled within a Bayesian framework and explicit regularization of model parameters is not required. The mobile position and number of cells means that global damping procedures, controlled by an optimal regularization parameter, are avoided. Many velocity models with variable numbers of cells are generated via a transdimensional Markov chain and information is extracted from the ensemble as a whole. As an aid to interpretation we visualize the expected earth model that is obtained via Monte Carlo integration in a straightforward manner. The procedure is particularly adept at imaging rapid changes or discontinuities in wave speed. While each velocity model in the final ensemble consists of many discontinuities at cell boundaries, these are smoothed out in the averaged ensemble solution while those required by the data are reinforced. The ensemble of models can also be used to produce uncertainty estimates and experiments with synthetic data suggest that they represent actual uncertainty surprisingly well. We use the fast marching method in order to iteratively update the ray geometry and account for the non-linearity of the problem. The method is tested here with synthetic data in a 2-D application and compared with a subspace method that is a more standard matrix-based inversion scheme. Preliminary results illustrate the advantages of the reversible jump algorithm. A real data example is also shown where a tomographic image of Rayleigh wave
Quantum Instantons and Quantum Chaos
Jirari, H.; Kröger, H.; Luo, X. Q.; Moriarty, K. J. M.; Rubin, S. G.
1999-01-01
Based on a closed form expression for the path integral of quantum transition amplitudes, we suggest rigorous definitions of both, quantum instantons and quantum chaos. As an example we compute the quantum instanton of the double well potential.
Hidden Statistics Approach to Quantum Simulations
Zak, Michail
2010-01-01
transitional potential is to provide a jump from a deterministic state to a random state with prescribed probability density. This jump is triggered by blowup instability due to violation of Lipschitz condition generated by the quantum potential. As a result, the dynamics attains quantum properties on a classical scale. The model can be implemented physically as an analog VLSI-based (very-large-scale integration-based) computer, or numerically on a digital computer. This work opens a way of developing fundamentally new algorithms for quantum simulations of exponentially complex problems that expand NASA capabilities in conducting space activities. It has been illustrated that the complexity of simulations of particle interaction can be reduced from an exponential one to a polynomial one.
International Nuclear Information System (INIS)
Xiang Guo-Yong; Guo Guang-Can
2013-01-01
The statistical error is ineluctable in any measurement. Quantum techniques, especially with the development of quantum information, can help us squeeze the statistical error and enhance the precision of measurement. In a quantum system, there are some quantum parameters, such as the quantum state, quantum operator, and quantum dimension, which have no classical counterparts. So quantum metrology deals with not only the traditional parameters, but also the quantum parameters. Quantum metrology includes two important parts: measuring the physical parameters with a precision beating the classical physics limit and measuring the quantum parameters precisely. In this review, we will introduce how quantum characters (e.g., squeezed state and quantum entanglement) yield a higher precision, what the research areas are scientists most interesting in, and what the development status of quantum metrology and its perspectives are. (topical review - quantum information)
A COMPARISON OF PAIRS FIGURE SKATERS IN REPEATED JUMPS
Directory of Open Access Journals (Sweden)
William A. Sands
2012-03-01
Full Text Available Trends in pairs figure skating have shown that increasingly difficult jumps have become an essential aspect of high-level performance, especially in the latter part of a competitive program. We compared a repeated jump power index in a 60 s repeated jump test to determine the relationship of repeated jump test to competitive rank and to measure 2D hip, knee, and ankle angles and angular velocities at 0, 20, 40, and 60 s. Eighteen National Team Pairs Figure Skaters performed a 60 s repeated jump test on a large switch-mat with timing of flight and ground durations and digital video recording. Each 60-s period was divided into 6, 10-s intervals, with power indexes (W/kg calculated for each 10-s interval. Power index by 10-s interval repeated measures ANOVAs (RMANOVA showed that males exceeded females at all intervals, and the highest power index interval was during 10 to 20 s for both sexes. RMANOVAs of angles and angular velocities showed main effects for time only. Power index and jumping techniques among figure skaters showed rapid and steady declines over the test duration. Power index can predict approximately 50% of competitive rank variance, and sex differences in jumping technique were rare
Validity of a jump training apparatus using Wii Balance Board.
Yamamoto, Keizo; Matsuzawa, Mamoru
2013-05-01
The dynamic quantification of jump ability is useful for sports performance evaluation. We developed a force measurement system using the Wii Balance Board (WBB). This study was conducted to validate the system in comparison with a laboratory-grade force plate (FP). For a static validation, weights of 10-180kg were put progressively on the WBB put on the FP. The vertical component of the ground reaction force (vGRF) was measured using both devices and compared. For the dynamic validation, 10 subjects without lower limb pathology participated in the study and performed vertical jumping twice on the WBB on the FP. The range of analysis was set from the landing after the first jump to taking off of the second jump. The peak values during the landing phase and jumping phase were obtained and the force-time integral (force impulse) was measured. The relations of the values measured using each device were compared using Pearson's correlation coefficient test and Bland-Altman plots (BAP). Significant correlation (P<.01, r=.99) was found between the values of both devices in the static and the dynamic test. Examination of the BAP revealed a proportion error in the landing phase and showed no relation in the jumping phase between the difference and the mean in the dynamic test. The WBB detects the vGRF in the jumping phase with high precision. Copyright © 2012 Elsevier B.V. All rights reserved.
Optimizing the Distribution of Leg Muscles for Vertical Jumping.
Directory of Open Access Journals (Sweden)
Jeremy D Wong
Full Text Available A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of
Optimizing the Distribution of Leg Muscles for Vertical Jumping
Wong, Jeremy D.; Bobbert, Maarten F.; van Soest, Arthur J.; Gribble, Paul L.; Kistemaker, Dinant A.
2016-01-01
A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas—which determine the maximum force deliverable by the muscles—constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal
Propulsion efficiency and imposed flow fields of a copepod jump.
Jiang, Houshuo; Kiørboe, Thomas
2011-02-01
Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed the imposed flow fields and associated energetics of jumps by means of computational fluid dynamics simulations by modeling the copepod as a self-propelled body. The computational fluid dynamics simulation was validated by particle image velocimetry data. The flow field generated by a repositioning jump quickly evolves into two counter-rotating viscous vortex rings that are near mirror image of one another, one in the wake and one around the body of the copepod; this near symmetrical flow may provide hydrodynamic camouflage because it contains no information about the position of the copepod prey within the flow structure. The flow field associated with an escape jump sequence also includes two dominant vortex structures: one leading wake vortex generated as a result of the first jump and one around the body, but between these two vortex structures is an elongated, long-lasting flow trail with flow velocity vectors pointing towards the copepod; such a flow field may inform the predator of the whereabouts of the escaping copepod prey. High Froude propulsion efficiency (0.94-0.98) was obtained for individual power stroke durations of all simulated jumps. This is unusual for small aquatic organisms but is caused by the rapidity and impulsiveness of the jump that allows only a low-cost viscous wake vortex to travel backwards.
Numerical simulations of katabatic jumps in coats land, Antartica
Yu, Ye; Cai, Xiaoming; King, John C.; Renfrew, Ian A.
A non-hydrostatic numerical model, the Regional Atmospheric Modeling System (RAMS), has been used to investigate the development of katabatic jumps in Coats Land, Antarctica. In the control run with a 5 m s-1downslope directed initial wind, a katabatic jump develops near the foot of the idealized slope. The jump is manifested as a rapid deceleration of the downslope flow and a change from supercritical to subcritical flow, in a hydraulic sense, i.e., the Froude number (Fr) of the flow changes from Fr > 1 to Fr> 1. Results from sensitivity experiments show that an increase in the upstream flow rate strengthens the jump, while an increase in the downstream inversion-layer depth results in a retreat of the jump. Hydraulic theory and Bernoulli''s theorem have been used to explain the surface pressure change across the jump. It is found that hydraulic theory always underestimates the surface pressure change, while Bernoulli''s theorem provides a satisfactory estimation. An analysis of the downs balance for the katabatic jump indicates that the important forces are those related to the pressure gradient, advection and, to a lesser extent, the turbulent momentum divergence. The development of katabatic jumps can be divided into two phases. In phase I, the t gradient force is nearly balanced by advection, while in phase II, the pressure gradient force is counterbalanced by turbulent momentum divergence. The upslope pressure gradient force associated with a pool of cold air over the ice shelf facilitates the formation of the katabatic jump.
Quantum Distinction: Quantum Distinctiones!
Zeps, Dainis
2009-01-01
10 pages; How many distinctions, in Latin, quantum distinctiones. We suggest approach of anthropic principle based on anthropic reference system which should be applied equally both in theoretical physics and in mathematics. We come to principle that within reference system of life subject of mathematics (that of thinking) should be equated with subject of physics (that of nature). For this reason we enter notions of series of distinctions, quantum distinction, and argue that quantum distinct...
Jump-Down Performance Alterations after Space Flight
Reschke, M. F.; Kofman, I. S.; Cerisano, J. M.; Fisher, E. A.; Peters, B. T.; Miller, C. A.; Harm, D. L.; Bloomberg, J. J.
2011-01-01
INTRODUCTION: Successful jump performance requires functional coordination of visual, vestibular, and somatosensory systems, which are affected by prolonged exposure to microgravity. Astronauts returning from space flight exhibit impaired ability to coordinate effective landing strategies when jumping from a platform to the ground. This study compares jump strategies used by astronauts before and after flight, changes to those strategies within a test session, and recoveries in jump-down performance parameters across several postflight test sessions. These data were obtained as part of an ongoing interdisciplinary study (Functional Task Test, FTT) designed to evaluate both astronaut postflight functional performance and related physiological changes. METHODS: Seven astronauts from short-duration (Shuttle) and three from long-duration (International Space Station) flights performed 3 two-footed jumps from a platform 30 cm high onto a force plate that measured the ground reaction forces and center-of-pressure displacement from the landings. Neuromuscular activation data were collected from the medial gastrocnemius and anterior tibialis of both legs using surface electromyography electrodes. Two load cells in the platform measured the load exerted by each foot during the takeoff phase of the jump. Data were collected in 2 preflight sessions, on landing day (Shuttle only), and 1, 6, and 30 days after flight. RESULTS: Postural settling time was significantly increased on the first postflight test session and many of the astronauts tested were unable to maintain balance on their first jump landing but recovered by the third jump, showing a learning progression in which performance improvements could be attributed to adjustments in takeoff or landing strategy. Jump strategy changes were evident in reduced air time (time between takeoff and landing) and also in increased asymmetry in foot latencies on takeoff. CONCLUSIONS: The test results revealed significant decrements
Temperature Jump Pyrolysis Studies of RP 2 Fuel
2017-01-09
Briefing Charts 3. DATES COVERED (From - To) 15 December 2016 – 11 January 2017 4. TITLE AND SUBTITLE Temperature Jump Pyrolysis Studies of RP-2 Fuel...Rev. 8- 98) Prescribed by ANSI Std. 239.18 1 TEMPERATURE JUMP PYROLYSIS STUDIES OF RP-2 FUEL Owen Pryor1, Steven D. Chambreau2, Ghanshyam L...17026 7 Temperature Jump Pyrolysis at AFRL Edwards Rapid heating of a metal filament at a rate of 600 – 800 K/s, and the set temperature is held for
Effects of kettlebell training on postural coordination and jump performance
DEFF Research Database (Denmark)
Jay, Kenneth; Jakobsen, Markus Due; Sundstrup, Emil
2013-01-01
ABSTRACT: The aim of this study was to investigate the effectiveness of a worksite intervention using kettlebell training to improve postural reactions to perturbation and jump performance.This single-blind randomized controlled trial involved 40 adults (n=40) from occupations with a high....... The outcome measures were postural reactions to sudden perturbation and maximal countermovement jump height.Compared to the control group, the training group significant decreased stopping time following perturbation (-109ms, 95% CI [-196:-21]). Jump height increased significantly in the training group (1.5cm...
Diarylethene microcrystals make directional jumps upon ultraviolet irradiation
International Nuclear Information System (INIS)
Colombier, I.; Spagnoli, S.; Corval, A.; Baldeck, P. L.; Giraud, M.; Leaustic, A.; Yu, P.; Irie, M.
2007-01-01
Microcrystals of a diarylethene {1,2-bis[5 ' -methyl-2 ' -(2 '' -pyridyl)thiazolyl]perfluorocyclo-pentene } undergo jumps upon photoirradiation. These photochromic crystals present molecular structural changes upon irradiation with ultraviolet light because of reversible photocyclization reactions. When the energy absorbed by crystals reaches about 10 μJ, the uniaxial stress induced in the crystal lattice relaxes through directional jumps. If one prevents crystals from jumping, then parallel, equidistant cracks appear on crystal surfaces. These photomechanical effects could result from a Grinfeld surface instability
Developing an Enhanced Lightning Jump Algorithm for Operational Use
Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.
2009-01-01
Overall Goals: 1. Build on the lightning jump framework set through previous studies. 2. Understand what typically occurs in nonsevere convection with respect to increases in lightning. 3. Ultimately develop a lightning jump algorithm for use on the Geostationary Lightning Mapper (GLM). 4 Lightning jump algorithm configurations were developed (2(sigma), 3(sigma), Threshold 10 and Threshold 8). 5 algorithms were tested on a population of 47 nonsevere and 38 severe thunderstorms. Results indicate that the 2(sigma) algorithm performed best over the entire thunderstorm sample set with a POD of 87%, a far of 35%, a CSI of 59% and a HSS of 75%.
The Perpetual American Put Option for Jump-Diffusions
Aase, Knut K.
2010-01-01
-This is the author's version of the article"The Perpetual American Put Option for Jump-Diffusions" Energy Systems pp 493-507. We solve a specific optimal stopping problem with an infinite time horizon, when the state variable follows a jump-diffusion. The novelty of the paper is related to the inclusion of a jump component in this stochastic process. Under certain conditions, our solution can be interpreted as the price of an American perpetual put option. We characterize the continuation...
Mechanism design and optimization of a bionic kangaroo jumping robot
Zhang, Y. H.; Zheng, L.; Ge, W. J.; Zou, Z. H.
2018-03-01
Hopping robots have broad application prospects in the fields of military reconnaissance, field search or life rescue. However, current hopping robots still face the problems of weak jumping ability and load bearing. Inspired by the jumping of kangaroo, we design a Kangaroo hopping robot “Zbot”, which has two degrees of freedom and three joints. The geared five-bar mechanism is used to decouple the knee and ankle joints of the robot. In order to get a bionic performance, the coupling mechanism parameters are optimized. The simulation and experiments show that the robot has an excellent jumping ability and load capacity.
Jumps in the curve of creep of the stainless steel
International Nuclear Information System (INIS)
Silveira, T.L.; Monteiro, S.N.
The discontinuous flow observed in creep for several stainless steels at certain streels conditions in the interval of temperatures from 550 to 800 0 C has been investigated. This phenomenon appears as repetitive jumps with strain and stress increments that could be evaluated and related to the tests variables. The stress increment increases, consistently, with the stress level at the jump. This Δo versus sigma relation is due to strain aging effects and is a consequence of the variation of the stain rate during the deformation band propagation which causes the jump [pt
Rate Theory for Correlated Processes: Double Jumps in Adatom Diffusion
DEFF Research Database (Denmark)
Jacobsen, J.; Jacobsen, Karsten Wedel; Sethna, J.
1997-01-01
We study the rate of activated motion over multiple barriers, in particular the correlated double jump of an adatom diffusing on a missing-row reconstructed platinum (110) surface. We develop a transition path theory, showing that the activation energy is given by the minimum-energy trajectory...... which succeeds in the double jump. We explicitly calculate this trajectory within an effective-medium molecular dynamics simulation. A cusp in the acceptance region leads to a root T prefactor for the activated rate of double jumps. Theory and numerical results agree....
International Nuclear Information System (INIS)
Kim, Seyoung
2017-01-01
In this study, we investigated how a jumping strategy changes with an increase in the vertical jump height for a resultant ground reaction force (GRF) vector. We expected that the resultant force vector between two sequential motion phases (i.e., countermovement and push-off) of the counter movement jump would significantly change with the vertical jump height to take advantage of the resulting supportive force (i.e., an initial push-off force larger than the body weight) through the counter movement phase. Nine healthy young subjects were instructed to jump straight up to five different height levels ranging from 191 cm to 221 cm, and the kinematic and kinetic data were obtained in regular trials. The results showed that a lower center of mass position and larger resultant force vector were clearly observed in a higher jump, implying that the counter movement strategy changed with the vertical jump height to prepare for sufficient joint deviation and obtain a force advantage for larger push-off work.
Energy Technology Data Exchange (ETDEWEB)
Kim, Seyoung [Korea Institute of Machinery and Materials(KIMM), Daejeon (Korea, Republic of)
2017-04-15
In this study, we investigated how a jumping strategy changes with an increase in the vertical jump height for a resultant ground reaction force (GRF) vector. We expected that the resultant force vector between two sequential motion phases (i.e., countermovement and push-off) of the counter movement jump would significantly change with the vertical jump height to take advantage of the resulting supportive force (i.e., an initial push-off force larger than the body weight) through the counter movement phase. Nine healthy young subjects were instructed to jump straight up to five different height levels ranging from 191 cm to 221 cm, and the kinematic and kinetic data were obtained in regular trials. The results showed that a lower center of mass position and larger resultant force vector were clearly observed in a higher jump, implying that the counter movement strategy changed with the vertical jump height to prepare for sufficient joint deviation and obtain a force advantage for larger push-off work.
Wright, Glenn A; Pustina, Andrew A; Mikat, Richard P; Kernozek, Thomas W
2012-03-01
The purpose of this study was to determine the efficacy of estimating peak lower body power from a maximal jump squat using 3 different vertical jump prediction equations. Sixty physically active college students (30 men, 30 women) performed jump squats with a weighted bar's applied load of 20, 40, and 60% of body mass across the shoulders. Each jump squat was simultaneously monitored using a force plate and a contact mat. Peak power (PP) was calculated using vertical ground reaction force from the force plate data. Commonly used equations requiring body mass and vertical jump height to estimate PP were applied such that the system mass (mass of body + applied load) was substituted for body mass. Jump height was determined from flight time as measured with a contact mat during a maximal jump squat. Estimations of PP (PP(est)) for each load and for each prediction equation were compared with criterion PP values from a force plate (PP(FP)). The PP(est) values had high test-retest reliability and were strongly correlated to PP(FP) in both men and women at all relative loads. However, only the Harman equation accurately predicted PP(FP) at all relative loads. It can therefore be concluded that the Harman equation may be used to estimate PP of a loaded jump squat knowing the system mass and peak jump height when more precise (and expensive) measurement equipment is unavailable. Further, high reliability and correlation with criterion values suggest that serial assessment of power production across training periods could be used for relative assessment of change by either of the prediction equations used in this study.
Rensing, N; Westermann, A; Möller, D; von Piekartz, H
2015-12-01
Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in
Quantum algorithms and quantum maps - implementation and error correction
International Nuclear Information System (INIS)
Alber, G.; Shepelyansky, D.
2005-01-01
Full text: We investigate the dynamics of the quantum tent map under the influence of errors and explore the possibilities of quantum error correcting methods for the purpose of stabilizing this quantum algorithm. It is known that static but uncontrollable inter-qubit couplings between the qubits of a quantum information processor lead to a rapid Gaussian decay of the fidelity of the quantum state. We present a new error correcting method which slows down this fidelity decay to a linear-in-time exponential one. One of its advantages is that it does not require redundancy so that all physical qubits involved can be used for logical purposes. We also study the influence of decoherence due to spontaneous decay processes which can be corrected by quantum jump-codes. It is demonstrated how universal encoding can be performed in these code spaces. For this purpose we discuss a new entanglement gate which can be used for lowest level encoding in concatenated error-correcting architectures. (author)
Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method)
DEFF Research Database (Denmark)
Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan
Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf......Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf...
Quantum trajectory approach to the geometric phase: open bipartite systems
International Nuclear Information System (INIS)
Yi, X X; Liu, D P; Wang, W
2005-01-01
Through the quantum trajectory approach, we calculate the geometric phase acquired by a bipartite system subjected to decoherence. The subsystems that compose the bipartite system interact with each other and then are entangled in the evolution. The geometric phase due to the quantum jump for both the bipartite system and its subsystems is calculated and analysed. As an example, we present two coupled spin-1/2 particles to detail the calculations
Quantum trajectory phase transitions in the micromaser.
Garrahan, Juan P; Armour, Andrew D; Lesanovsky, Igor
2011-08-01
We study the dynamics of the single-atom maser, or micromaser, by means of the recently introduced method of thermodynamics of quantum jump trajectories. We find that the dynamics of the micromaser displays multiple space-time phase transitions, i.e., phase transitions in ensembles of quantum jump trajectories. This rich dynamical phase structure becomes apparent when trajectories are classified by dynamical observables that quantify dynamical activity, such as the number of atoms that have changed state while traversing the cavity. The space-time transitions can be either first order or continuous, and are controlled not just by standard parameters of the micromaser but also by nonequilibrium "counting" fields. We discuss how the dynamical phase behavior relates to the better known stationary-state properties of the micromaser.
Hydraulic jump and Bernoulli equation in nonlinear shallow water model
Sun, Wen-Yih
2018-06-01
A shallow water model was applied to study the hydraulic jump and Bernoulli equation across the jump. On a flat terrain, when a supercritical flow plunges into a subcritical flow, discontinuity develops on velocity and Bernoulli function across the jump. The shock generated by the obstacle may propagate downstream and upstream. The latter reflected from the inflow boundary, moves downstream and leaves the domain. Before the reflected wave reaching the obstacle, the short-term integration (i.e., quasi-steady) simulations agree with Houghton and Kasahara's results, which may have unphysical complex solutions. The quasi-steady flow is quickly disturbed by the reflected wave, finally, flow reaches steady and becomes critical without complex solutions. The results also indicate that Bernoulli function is discontinuous but the potential of mass flux remains constant across the jump. The latter can be used to predict velocity/height in a steady flow.
A quasi-static treatment of multiple phase jumps
International Nuclear Information System (INIS)
Englman, R; Vertesi, T
2005-01-01
A quasi-static, WKB-type treatment accounts well for the surprising phase jumps that are odd multiples of π (1 + 2n)π, found as a molecular system journeys adiabatically in a configuration coordinate plane that contains several points of degeneracies. We show that the number n in the phase jump is an integer close to |n'| that appears in the expression for the complex wavefunction amplitude valid (approximately) for times close to when the phase jump occurs: -δT + 2πθ+πn'sinδT -i[1-πn'cosδT](δT is a shifted and rescaled trajectory-time parameter and θ is a numerical fraction (<1) which depends on the adiabaticity of the motion.) The central quantity n' is local, i.e., depends on the values of the parameters in the Hamiltonian only at the beginning of the trajectory and at the instant of the phase jump
Trading price jump clusters in foreign exchange markets
Czech Academy of Sciences Publication Activity Database
Novotný, Jan; Petrov, D.; Urga, G.
2015-01-01
Roč. 24, June (2015), s. 66-92 ISSN 1386-4181 Institutional support: PRVOUK-P23 Keywords : price jumps * foreign exchange markets * trading Subject RIV: AH - Economics Impact factor: 1.726, year: 2015
The fluid dynamics of swimming by jumping in copepods
DEFF Research Database (Denmark)
Jiang, Houshuo; Kiørboe, Thomas
2011-01-01
Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic...... limited and temporally ephemeral owing to jump-impulsiveness and viscous decay. In contrast, continuous steady swimming generates two well-extended long-lasting momentum jets both in front of and behind the swimmer, as suggested by the well-known steady stresslet model. Based on the observed jump-swimming...... kinematics of a small copepod Oithona davisae, we further showed that jump-swimming produces a hydrodynamic disturbance with much smaller spatial extension and shorter temporal duration than that produced by a same-size copepod cruising steadily at the same average translating velocity. Hence, small copepods...
Hiding information in open auctions with jump bids
Czech Academy of Sciences Publication Activity Database
Ettinger, D.; Michelucci, Fabio
2016-01-01
Roč. 126, č. 594 (2016), s. 1484-1502 ISSN 0013-0133 Institutional support: RVO:67985998 Keywords : hiding information * open auctions * jump bids Subject RIV: AH - Economics Impact factor: 2.608, year: 2016
METRIC TESTS CHARACTERISTIC FOR ESTIMATING JUMPING FOR VOLLEYBALL PLAYERS
Directory of Open Access Journals (Sweden)
Toplica Stojanović
2008-08-01
Full Text Available With goal to establish metric tests characteristics for estimating jumping for volleyball players, it was organized a pilot research on pattern of 23 volleyball players from cadet team and 23 students from high-school. For needs of this research four tests are valid for estimation, jump in block with left and right leg and jump in spike with left and right leg. Each test has been taken three times, so that we could with test-re test method determine their reliability, and with factor analysis their validity. Data were processed by multivariate analysis (item analysis, factor analysis from statistical package „Statistica 6.0 for windows“. On the results of research and discussion we can say that the tests had high coefficient of reliability, as well as factor validity, and these tests can be used to estimate jumping for volleyball players.
Jump diffusion models and the evolution of financial prices
International Nuclear Information System (INIS)
Figueiredo, Annibal; Castro, Marcio T. de; Silva, Sergio da; Gleria, Iram
2011-01-01
We analyze a stochastic model to describe the evolution of financial prices. We consider the stochastic term as a sum of the Wiener noise and a jump process. We point to the effects of the jumps on the return time evolution, a central concern of the econophysics literature. The presence of jumps suggests that the process can be described by an infinitely divisible characteristic function belonging to the De Finetti class. We then extend the De Finetti functions to a generalized nonlinear model and show the model to be capable of explaining return behavior. -- Highlights: → We analyze a stochastic model to describe the evolution of financial prices. → The stochastic term is considered as a sum of the Wiener noise and a jump process. → The process can be described by an infinitely divisible characteristic function belonging to the De Finetti class. → We extend the De Finetti functions to a generalized nonlinear model.
Hiding information in open auctions with jump bids
Czech Academy of Sciences Publication Activity Database
Ettinger, D.; Michelucci, Fabio
2016-01-01
Roč. 126, č. 594 (2016), s. 1484-1502 ISSN 0013-0133 Institutional support: PRVOUK-P23 Keywords : hiding information * open auctions * jump bids Subject RIV: AH - Economics Impact factor: 2.608, year: 2016
The exit-time problem for a Markov jump process
Burch, N.; D'Elia, M.; Lehoucq, R. B.
2014-12-01
The purpose of this paper is to consider the exit-time problem for a finite-range Markov jump process, i.e, the distance the particle can jump is bounded independent of its location. Such jump diffusions are expedient models for anomalous transport exhibiting super-diffusion or nonstandard normal diffusion. We refer to the associated deterministic equation as a volume-constrained nonlocal diffusion equation. The volume constraint is the nonlocal analogue of a boundary condition necessary to demonstrate that the nonlocal diffusion equation is well-posed and is consistent with the jump process. A critical aspect of the analysis is a variational formulation and a recently developed nonlocal vector calculus. This calculus allows us to pose nonlocal backward and forward Kolmogorov equations, the former equation granting the various moments of the exit-time distribution.
Impulsive evolution inclusions with infinite delay and multivalued jumps
Directory of Open Access Journals (Sweden)
Mouffak Benchohra
2012-08-01
Full Text Available In this paper we prove the existence of a mild solution for a class of impulsive semilinear evolution differential inclusions with infinite delay and multivalued jumps in a Banach space.
Swarm algorithms with chaotic jumps for optimization of multimodal functions
Krohling, Renato A.; Mendel, Eduardo; Campos, Mauro
2011-11-01
In this article, the use of some well-known versions of particle swarm optimization (PSO) namely the canonical PSO, the bare bones PSO (BBPSO) and the fully informed particle swarm (FIPS) is investigated on multimodal optimization problems. A hybrid approach which consists of swarm algorithms combined with a jump strategy in order to escape from local optima is developed and tested. The jump strategy is based on the chaotic logistic map. The hybrid algorithm was tested for all three versions of PSO and simulation results show that the addition of the jump strategy improves the performance of swarm algorithms for most of the investigated optimization problems. Comparison with the off-the-shelf PSO with local topology (l best model) has also been performed and indicates the superior performance of the standard PSO with chaotic jump over the standard both using local topology (l best model).
Spinal column damage from water ski jumping
International Nuclear Information System (INIS)
Horne, J.; Cockshott, W.P.; Shannon, H.S.
1987-01-01
We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children. (orig.)
Spinal column damage from water ski jumping.
Horne, J; Cockshott, W P; Shannon, H S
1987-01-01
We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children.
Why do oil prices jump (or fall)?
International Nuclear Information System (INIS)
Wirl, Franz
2008-01-01
This paper discusses theories that can explain the zig-zags of oil prices in general and in particular the recent jump. More precisely, the following explanations are discussed: Homo oeconomicus (pure profit maximization if demand is dynamic and convex), price reaction function (price increases and respectively declines depend on capacity utilization), cartelization contingent on output or revenues of which the latter can lead to backward bending supply segments and multiple equilibria, statistical descriptions (mean reversion), homo politicus, i.e., arguments for price hikes that are rational (Public Choice) despite the (long-run) economic loss. Finally two approaches are presented that emphasize demand uncertainty: one extending the above-mentioned dynamic demand framework and the other considers a dynamic game of non-competitive suppliers with lumpy investments. Summing up, a demand shock seems to be the most suitable explanation of today's high prices (indeed a shock given that International Energy Agency (IEA) and Department of Energy (DoE) were promising just a couple of years ago that we are going to have lots of oil at low prices), while others and in particular politics have surprisingly little or no explanatory power. (author)
Ethics in radiology: wait lists queue jumping.
Cunningham, Natalie; Reid, Lynette; MacSwain, Sarah; Clarke, James R
2013-08-01
Education in ethics is a requirement for all Royal College residency training programs as laid out in the General Standards of Accreditation for residency programs in Canada. The ethical challenges that face radiologists in clinical practice are often different from those that face other physicians, because the nature of the physician-patient interaction is unlike that of many other specialties. Ethics education for radiologists and radiology residents will benefit from the development of teaching materials and resources that focus on the issues that are specific to the specialty. This article is intended to serve as an educational resource for radiology training programs to facilitate teaching ethics to residents and also as a continuing medical education resource for practicing radiologists. In an environment of limited health care resources, radiologists are frequently asked to expedite imaging studies for patients and, in some respects, act as gatekeepers for specialty care. The issues of wait lists, queue jumping, and balancing the needs of individuals and society are explored from the perspective of a radiologist. Copyright © 2013 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.
Vortex jump behavior in coupled nanomagnetic heterostructures
International Nuclear Information System (INIS)
Zhang, S.; Phatak, C.; Petford-Long, A. K.; Heinonen, O.
2014-01-01
The spin configuration and magnetic behavior in patterned nanostructures can be controlled by manipulating the interplay between the competing energy terms. This in turn requires fundamental knowledge of the magnetic interactions at the local nanometer scale. Here, we report on the spin structure and magnetization behavior of patterned discs containing exchange coupled ferromagnetic layers with additional exchange bias to an antiferromagnetic layer. The magnetization reversal was explored by direct local visualization of the domain behavior using in-situ Lorentz transmission electron microscopy, from which quantitative magnetic induction maps were reconstructed. The roles of the main competing energy terms were elucidated and the reversal mechanism was identified as a coupled phenomenon of incoherent rotation in the exchange-biased layer and localized vortex nucleation and discontinuous propagation in the free layer, including an anomalous jump in the trajectory. The observations were supported by micromagnetic simulations and modeled phase shift simulations. The work presented here provides fundamental insights into opportunities for macroscopic control of the energy landscape of magnetic heterostructures for functional applications
Spinal column damage from water ski jumping
Energy Technology Data Exchange (ETDEWEB)
Horne, J.; Cockshott, W.P.; Shannon, H.S.
1987-11-01
We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children. (orig.)
Vortex jump behavior in coupled nanomagnetic heterostructures
Energy Technology Data Exchange (ETDEWEB)
Zhang, S.; Phatak, C., E-mail: cd@anl.gov [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States); Petford-Long, A. K. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208 (United States); Heinonen, O. [Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208-3112 (United States)
2014-11-24
The spin configuration and magnetic behavior in patterned nanostructures can be controlled by manipulating the interplay between the competing energy terms. This in turn requires fundamental knowledge of the magnetic interactions at the local nanometer scale. Here, we report on the spin structure and magnetization behavior of patterned discs containing exchange coupled ferromagnetic layers with additional exchange bias to an antiferromagnetic layer. The magnetization reversal was explored by direct local visualization of the domain behavior using in-situ Lorentz transmission electron microscopy, from which quantitative magnetic induction maps were reconstructed. The roles of the main competing energy terms were elucidated and the reversal mechanism was identified as a coupled phenomenon of incoherent rotation in the exchange-biased layer and localized vortex nucleation and discontinuous propagation in the free layer, including an anomalous jump in the trajectory. The observations were supported by micromagnetic simulations and modeled phase shift simulations. The work presented here provides fundamental insights into opportunities for macroscopic control of the energy landscape of magnetic heterostructures for functional applications.
A jumping shape memory alloy under heat.
Yang, Shuiyuan; Omori, Toshihiro; Wang, Cuiping; Liu, Yong; Nagasako, Makoto; Ruan, Jingjing; Kainuma, Ryosuke; Ishida, Kiyohito; Liu, Xingjun
2016-02-16
Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L2(1) parent before deformation, the 2H martensite stress-induced from L2(1) parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials.
I Gusti Ngurah Agung Cahya Prananta; N. Adiputra; I P G Adiatmika
2015-01-01
The effectiveness of jump-shoot technique step jump shoot and still jump shoot in a game is still questionable, because many different assumptions arise. One opinion stated that step jump shoot was more effective and the other stated that and still jump shoot was more efective. Therefore it is necessary to do research on the analysis of the results of step jump shoot and and still jump shoot to improve the accuracy of shooting in a basketball. The experimental research had been conducted on...
Transition-energy crossing with a γt-jump
International Nuclear Information System (INIS)
Wei, Jie; Peggs, S.
1994-01-01
Expressions for the minimum size and speed of a transition-energy (γ t -) jump needed to diminish the chromatic non-linear effect, the self-field mismatch, and the microwave instabilities in the Relativistic Heavy Ion Collider (RHIC) are obtained. A γ t -jump of 0.8 units is needed to be performed within 60 ms in order to achieve a ''clean'' transition crossing
Local uncontrollability for affine control systems with jumps
Treanţă, Savin
2017-09-01
This paper investigates affine control systems with jumps for which the ideal If(g1, …, gm) generated by the drift vector field f in the Lie algebra L(f, g1, …, gm) can be imbedded as a kernel of a linear first-order partial differential equation. It will lead us to uncontrollable affine control systems with jumps for which the corresponding reachable sets are included in explicitly described differentiable manifolds.
Hypohydration Reduces Vertical Ground Reaction Impulse But Not Jump Height
2010-01-01
height, provided that muscle contractile function remains normal, because gravitational and inertial resistance to jumping are pro- portional to body...testing, anthropometric and fitness measurements were made to characterize the study population. Peak aerobic power (VO2peak) was determined using an...determinations. All volunteers performed between 3 and 5 practice days of vertical jump testing to reduce training and learning effects. Practice
Knee Muscular Control During Jump Landing in Multidirections
Sinsurin, Komsak; Vachalathiti, Roongtiwa; Jalayondeja, Wattana; Limroongreungrat, Weerawat
2016-01-01
Background Jump landing is a complex movement in sports. While competing and practicing, athletes frequently perform multi-planar jump landing. Anticipatory muscle activity could influence the amount of knee flexion and prepare the knee for dynamic weight bearing such as landing tasks. Objectives The aim of the present study was to examine knee muscle function and knee flexion excursion as athletes naturally performed multi-direct...
Seismic interpretation of the triangle zone at Jumping Pound, Alberta
Energy Technology Data Exchange (ETDEWEB)
Slotboom, R. T. [Amerada Hess Canada Ltd., Calgary, AB (Canada); Lawton, D. C.; Spratt, D. A. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics
1996-06-01
The triangle zone at Jumping Point, Alberta was characterized using seismic survey data as a NW-SE-trending antiformal stack of thrust sheets involving Cretaceous rocks that have been wedged into the foreland between two detachments. Three major thrust sheets of Lower and Upper Cretaceous strata have been stacked to form the main extremity of the wedge. The structure is tightly folded at Jumping Point, and broadens northwest along the strike. 13 refs., 8 figs.
Kinematic structure at the early flight position in ski jumping.
Vodičar, Janez; Coh, Milan; Jošt, Bojan
2012-12-01
The purpose of our research was to establish the variability of correlation between the length of the jumps and selected multi-item kinematic variables (n=9) in the early flight phase technique of ski jumping. This study was conducted on a sample of elite Slovenian ski jumpers (N=29) who participated in the experiment on a jumping hill in Hinterzarten, Germany (HS95m) on the 20(th) of August, 2008. The highest and most significant correlations (p=0.01) with the length of the ski jump were found in the multi-item variable height of flying, which was also expressed with the highest level of stability of the explained total variance (TV) on the first factor (TV=69.13%). The most important characteristic of the aerodynamic aspect of early flight was the variable angle between the body chord and the horizontal axis with significantly high correlations (pjump. Only two more variables, the angle between the upper body and the horizontal plane (TV=53.69%), and the angle between left ski and left leg (TV=50.13%), had an explained common variance on the first factor greater than 50% of total variance. The results indicated that some kinematic parameters of ski jumping early flight technique were more important for success considering the length of the jump.
Discharge regimes and density jumps in a helicon plasma source
International Nuclear Information System (INIS)
Shinohara, S.; Yonekura, K.
1999-01-01
A high density plasma source using a helicon wave is becoming very attractive in plasma processing and confinement devices. In the previous work, the characteristics of this wave and plasma performance with diameters of 5 and 45 cm have been studied, and the helicon wave was only observed after the density jump. Recently, density jumps from the low to high electron densities with a level of 10 13 cm -3 were investigated by changing the antenna wavenumber spectrum, and the obtained results were compared with the inductively coupled plasma (ICP). However, the mechanisms of density jumps and plasma production are still open questions to be answered. Here, the authors try to investigate the discharge regimes and density jumps in a helicon plasma source, by changing the antenna wavenumber spectrum. For he case of the parallel current directions in the antenna, where the low wavenumber spectrum part is large, the density jump was observed with the low RF input power of P in < 300 W regardless of the magnetic field. On the other hand, for the case of the opposite directions, where the low wavenumber spectrum part is small, the threshold power to obtain the jump became high with the increase in the magnetic field. This can be understood from the dispersion relation of the helicon wave. The wave structures and the dispersion relations in the discharge modes will be also shown
Kinetic asymmetries between forward and drop jump landing tasks
Directory of Open Access Journals (Sweden)
Morgana Alves de Britto
2015-12-01
Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n6p661 Landing asymmetry is a risk factor for knee anterior cruciate ligament injury. The aim of this study was to identify kinetic asymmetries in healthy recreational athletes performing different jump-landing techniques. Twelve recreational athletes engaged in regular training underwent kinetic evaluation using two 3D force plates and were analyzed for: (a three-dimensional peak forces, (b time to peak vertical force, and (c initial phase asymmetries. All data were collected during performance of unilateral and bilateral trials of forward and drop jump tasks. Forward jump-landing tasks elicited greater kinetic asymmetry than drop-landing tasks. Regardless of jump-landing technique, the preferred leg experienced higher forces than the non-preferred leg. The initial landing phase showed more kinetic asymmetries than the later phase when peak vertical forces occur. It was concluded that when screening athletes for kinetic asymmetries that may predispose them to injury, forward jump-landing tasks and the early landing phase might show more kinetic asymmetries than drop jump-landing tasks and the late landing phase, respectively.
the Modeling of Hydraulic Jump Generated Partially on Sloping Apron
Directory of Open Access Journals (Sweden)
Shaker Abdulatif Jalil
2017-12-01
Full Text Available Modeling aims to characterize system behavior and achieve simulation close as possible of the reality. The rapid energy exchange in supercritical flow to generate quiet or subcritical flow in hydraulic jump phenomenon is important in design of hydraulic structures. Experimental and numerical modeling is done on type B hydraulic jump which starts first on sloping bed and its end on horizontal bed. Four different apron slopes are used, for each one of these slopes the jump is generated on different locations by controlling the tail water depth. Modelling validation is based on 120 experimental runs which they show that there is reliability. The air volume fraction which creates in through hydraulic jump varied between 0.18 and 0.28. While the energy exchanges process take place within 6.6, 6.1, 5.8, 5.5 of the average relative jump height for apron slopes of 0.18, 0.14, 0.10, 0.07 respectively. Within the limitations of this study, mathematical prediction model for relative hydraulic jump height is suggested.The model having an acceptable coefficient of determination.
Quantum walks, quantum gates, and quantum computers
International Nuclear Information System (INIS)
Hines, Andrew P.; Stamp, P. C. E.
2007-01-01
The physics of quantum walks on graphs is formulated in Hamiltonian language, both for simple quantum walks and for composite walks, where extra discrete degrees of freedom live at each node of the graph. It is shown how to map between quantum walk Hamiltonians and Hamiltonians for qubit systems and quantum circuits; this is done for both single-excitation and multiexcitation encodings. Specific examples of spin chains, as well as static and dynamic systems of qubits, are mapped to quantum walks, and walks on hyperlattices and hypercubes are mapped to various gate systems. We also show how to map a quantum circuit performing the quantum Fourier transform, the key element of Shor's algorithm, to a quantum walk system doing the same. The results herein are an essential preliminary to a Hamiltonian formulation of quantum walks in which coupling to a dynamic quantum environment is included
Planar Quantum Mechanics: an Intriguing Supersymmetric Example
Veneziano, Gabriele
2006-01-01
After setting up a Hamiltonian formulation of planar (matrix) quantum mechanics, we illustrate its effectiveness in a non-trivial supersymmetric example. The numerical and analytical study of two sectors of the model, as a function of 't Hooft's coupling $\\lambda$, reveals both a phase transition at $\\lambda=1$ (disappearence of the mass gap and discontinuous jump in Witten's index) and a new form of strong-weak duality for $\\lambda \\to 1/\\lambda$.
Le Gouët, Jean-Louis; Moiseev, Sergey
2012-06-01
Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The
Chang, Mou-Hsiung
2015-01-01
The classical probability theory initiated by Kolmogorov and its quantum counterpart, pioneered by von Neumann, were created at about the same time in the 1930s, but development of the quantum theory has trailed far behind. Although highly appealing, the quantum theory has a steep learning curve, requiring tools from both probability and analysis and a facility for combining the two viewpoints. This book is a systematic, self-contained account of the core of quantum probability and quantum stochastic processes for graduate students and researchers. The only assumed background is knowledge of the basic theory of Hilbert spaces, bounded linear operators, and classical Markov processes. From there, the book introduces additional tools from analysis, and then builds the quantum probability framework needed to support applications to quantum control and quantum information and communication. These include quantum noise, quantum stochastic calculus, stochastic quantum differential equations, quantum Markov semigrou...
Scarani, Valerio
1998-01-01
The aim of this thesis was to explain what quantum computing is. The information for the thesis was gathered from books, scientific publications, and news articles. The analysis of the information revealed that quantum computing can be broken down to three areas: theories behind quantum computing explaining the structure of a quantum computer, known quantum algorithms, and the actual physical realizations of a quantum computer. The thesis reveals that moving from classical memor...
Wu, Lian-Ao; Lidar, Daniel A.
2005-01-01
When quantum communication networks proliferate they will likely be subject to a new type of attack: by hackers, virus makers, and other malicious intruders. Here we introduce the concept of "quantum malware" to describe such human-made intrusions. We offer a simple solution for storage of quantum information in a manner which protects quantum networks from quantum malware. This solution involves swapping the quantum information at random times between the network and isolated, distributed an...
Quantumness beyond quantum mechanics
International Nuclear Information System (INIS)
Sanz, Ángel S
2012-01-01
Bohmian mechanics allows us to understand quantum systems in the light of other quantum traits than the well-known ones (coherence, diffraction, interference, tunnelling, discreteness, entanglement, etc.). Here the discussion focusses precisely on two of these interesting aspects, which arise when quantum mechanics is thought within this theoretical framework: the non-crossing property, which allows for distinguishability without erasing interference patterns, and the possibility to define quantum probability tubes, along which the probability remains constant all the way. Furthermore, taking into account this hydrodynamic-like description as a link, it is also shown how this knowledge (concepts and ideas) can be straightforwardly transferred to other fields of physics (for example, the transmission of light along waveguides).
Coupled jump rotational dynamics in aqueous nitrate solutions.
Banerjee, Puja; Yashonath, Subramanian; Bagchi, Biman
2016-12-21
A nitrate ion (NO 3 - ) with its trigonal planar geometry and charges distributed among nitrogen and oxygen atoms can couple to the extensive hydrogen bond network of water to give rise to unique dynamical characteristics. We carry out detailed atomistic simulations and theoretical analyses to investigate these aspects and report certain interesting findings. We find that the nitrate ions in aqueous potassium nitrate solution exhibit large amplitude rotational jump motions that are coupled to the hydrogen bond rearrangement dynamics of the surrounding water molecules. The jump motion of nitrate ions bears certain similarities to the Laage-Hynes mechanism of rotational jump motions of tagged water molecules in neat liquid water. We perform a detailed atomic-level investigation of hydrogen bond rearrangement dynamics of water in aqueous KNO 3 solution to unearth two distinct mechanisms of hydrogen bond exchange that are instrumental to promote these jump motions of nitrate ions. As observed in an earlier study by Xie et al., in the first mechanism, after breaking a hydrogen bond with nitrate ion, water forms a new hydrogen bond with a water molecule, whereas the second mechanism involves just a switching of hydrogen bond between the two oxygen atoms of the same nitrate ion (W. J. Xie et al., J. Chem. Phys. 143, 224504 (2015)). The magnitude as well as nature of the reorientational jump of nitrate ion for the two mechanisms is different. In the first mechanism, nitrate ion predominantly undergoes out-of-plane rotation, while in the second mechanism, in-plane reorientation of NO 3 - is favourable. These have been deduced by computing the torque on the nitrate ion during the hydrogen bond switching event. We have defined and computed the time correlation function for coupled reorientational jump of nitrate and water and obtained the associated relaxation time which is also different for the two mechanisms. These results provide insight into the relation between the
Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons
Kröger, H.
2003-01-01
We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.
The Role of Quantum Decoherence in FRET.
Nelson, Philip C
2018-02-16
Resonance energy transfer has become an indispensable experimental tool for single-molecule and single-cell biophysics. Its physical underpinnings, however, are subtle: it involves a discrete jump of excitation from one molecule to another, and so we regard it as a strongly quantum-mechanical process. And yet its kinetics differ from what many of us were taught about two-state quantum systems, quantum superpositions of the states do not seem to arise, and so on. Although J. R. Oppenheimer and T. Förster navigated these subtleties successfully, it remains hard to find an elementary derivation in modern language. The key step involves acknowledging quantum decoherence. Appreciating that aspect can be helpful when we attempt to extend our understanding to situations in which Förster's original analysis is not applicable. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
H. Makaruk
2014-07-01
Full Text Available The aim of this study was to examine the chronic effects of single and repeated jumps training on vertical landing force (VGRF and jump height in untrained men. The VGRF and jump height were compared after a six-week plyometric training programme containing single and repeated jumps, together with two additional parameters: landing time (LT and range of the knee flexion during landing (KF. Thirty-six untrained physical education students with a plyometric training background were randomly assigned to a single jump group (SJG, n =12, repeated jumps group (RJG, n =12, and control group (CON, n =12. The SJG performed only single jumps, the RJG executed repeated (consecutive jumps, whereas the CON did not perform any exercises at all. A countermovement jump (CMJ, repeated countermovement jumps (RCMJ, and a drop jump (DJ were tested before and after the training. Only the RJG showed a significantly reduced VGRF (p<0.05 in all tests. Both plyometric groups significantly improved (p<0.05 their jump height in all tests. The LT was significantly greater in the RJG, compared to the SJG, in all tests. The KF was also significantly (p<0.05 greater in the RJG than in the SJG for CMJ and RCMJ. The results suggest that repeated jumps are beneficial for simultaneous landing force reduction and jumping performance enhancement.
A data-driven wavelet-based approach for generating jumping loads
Chen, Jun; Li, Guo; Racic, Vitomir
2018-06-01
This paper suggests an approach to generate human jumping loads using wavelet transform and a database of individual jumping force records. A total of 970 individual jumping force records of various frequencies were first collected by three experiments from 147 test subjects. For each record, every jumping pulse was extracted and decomposed into seven levels by wavelet transform. All the decomposition coefficients were stored in an information database. Probability distributions of jumping cycle period, contact ratio and energy of the jumping pulse were statistically analyzed. Inspired by the theory of DNA recombination, an approach was developed by interchanging the wavelet coefficients between different jumping pulses. To generate a jumping force time history with N pulses, wavelet coefficients were first selected randomly from the database at each level. They were then used to reconstruct N pulses by the inverse wavelet transform. Jumping cycle periods and contract ratios were then generated randomly based on their probabilistic functions. These parameters were assigned to each of the N pulses which were in turn scaled by the amplitude factors βi to account for energy relationship between successive pulses. The final jumping force time history was obtained by linking all the N cycles end to end. This simulation approach can preserve the non-stationary features of the jumping load force in time-frequency domain. Application indicates that this approach can be used to generate jumping force time history due to single people jumping and also can be extended further to stochastic jumping loads due to groups and crowds.
CONNECTION OF FUNCTIONAL ABILITIES WITH JUMPING AND THROWING ATHLETIC DISCIPLINES
Directory of Open Access Journals (Sweden)
Igor Stanojević
2014-06-01
Full Text Available The aim of this study was to determine the connection between functional abilities with results of jumping and throwing athletic disciplines with athletes. The sample was taken from a population of elementary school students from Prokuplje region, 13 and 14 old, included in regular physical education classes. The sample consisted of 200 male athletes involved in the training process in sports clubs at least three times a week in addition to physical education classes. For assessment of functional abilities six functional tests were used: resting heart rate, Cooper test, heart rate in the first minute after Cooper test, heart rate in the second minute after Cooper test, systolic arterial blood pressure, diastolic arterial blood pressure. For assessment of jumping and throwing athletic disciplines four tests were used: long jump, high jump, shot put and javelin. Data analysis was performed with canonical correlation and regression analysis. The results showed a statistically significant correlation between functional abilities with all of tests in jumping and throwing athletic disciplines.
Mechanical parameters and flight phase characteristics in aquatic plyometric jumping.
Louder, Talin J; Searle, Cade J; Bressel, Eadric
2016-09-01
Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water. Kinetic force platform data from 12 young, male adults were collected for counter-movement jumps performed on land and in water at two different immersion depths. The specificity of jumps between environmental conditions was assessed using kinetic measures, temporal characteristics, and an assessment of the statistical relationship between take-off velocity and time in the air. Greater peak mechanical power was observed for jumps performed in the water, and was influenced by immersion depth. Additionally, the data suggest that, in the water, the statistical relationship between take-off velocity and time in air is quadratic. Results highlight the potential application of aquatic plyometric training as a cross-training tool for improving mechanical power and suggest that water immersion depth and fluid drag play key roles in the specificity of the take-off phase for jumping movements performed in the water.
Anthropic prediction for a large multi-jump landscape
International Nuclear Information System (INIS)
Schwartz-Perlov, Delia
2008-01-01
The assumption of a flat prior distribution plays a critical role in the anthropic prediction of the cosmological constant. In a previous paper we analytically calculated the distribution for the cosmological constant, including the prior and anthropic selection effects, in a large toy 'single-jump' landscape model. We showed that it is possible for the fractal prior distribution that we found to behave as an effectively flat distribution in a wide class of landscapes, but only if the single-jump size is large enough. We extend this work here by investigating a large (N∼10 500 ) toy 'multi-jump' landscape model. The jump sizes range over three orders of magnitude and an overall free parameter c determines the absolute size of the jumps. We will show that for 'large' c the distribution of probabilities of vacua in the anthropic range is effectively flat, and thus the successful anthropic prediction is validated. However, we argue that for small c, the distribution may not be smooth
Self-jumping Mechanism of Melting Frost on Superhydrophobic Surfaces.
Liu, Xiaolin; Chen, Huawei; Zhao, Zehui; Wang, Yamei; Liu, Hong; Zhang, Deyuan
2017-11-07
Frost accretion on surfaces may cause severe problems and the high-efficiency defrosting methods are still urgently needed in many application fields like heat transfer, optical and electric power system, etc. In this study, a nano-needle superhydrophobic surface is prepared and the frosting/defrosting experiments are conducted on it. Three steps are found in the defrosting process: melting frost shrinking and splitting, instantaneous self-triggered deforming followed by deformation-induced movements (namely, in-situ shaking, rotating, rolling, and self-jumping). The self-jumping performance of the melting frost is extremely fascinating and worth studying due to its capability of evidently shortening the defrosting process and reducing (even avoiding) residual droplets after defrosting. The study on the melting frost self-jumping phenomena demonstrates that the kinetic energy transformed from instantaneous superficial area change in self-triggered deforming step is the intrinsic reason for various melting frost self-propelled movements, and when the transformed energy reaches a certain amount, the self-jumping phenomena occur. And some facilitating conditions for melting frost self-jumping phenomena are also discussed. This work will provide an efficient way for defrosting or an inspiration for further research on defrosting.
Bayesian inference for Markov jump processes with informative observations.
Golightly, Andrew; Wilkinson, Darren J
2015-04-01
In this paper we consider the problem of parameter inference for Markov jump process (MJP) representations of stochastic kinetic models. Since transition probabilities are intractable for most processes of interest yet forward simulation is straightforward, Bayesian inference typically proceeds through computationally intensive methods such as (particle) MCMC. Such methods ostensibly require the ability to simulate trajectories from the conditioned jump process. When observations are highly informative, use of the forward simulator is likely to be inefficient and may even preclude an exact (simulation based) analysis. We therefore propose three methods for improving the efficiency of simulating conditioned jump processes. A conditioned hazard is derived based on an approximation to the jump process, and used to generate end-point conditioned trajectories for use inside an importance sampling algorithm. We also adapt a recently proposed sequential Monte Carlo scheme to our problem. Essentially, trajectories are reweighted at a set of intermediate time points, with more weight assigned to trajectories that are consistent with the next observation. We consider two implementations of this approach, based on two continuous approximations of the MJP. We compare these constructs for a simple tractable jump process before using them to perform inference for a Lotka-Volterra system. The best performing construct is used to infer the parameters governing a simple model of motility regulation in Bacillus subtilis.
The kinematics of swimming and relocation jumps in copepod nauplii
DEFF Research Database (Denmark)
Borg, Marc Andersen; Bruno, Eleonora; Kiørboe, Thomas
2012-01-01
Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and cop......Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella...... of pelagic copepods: Temora longicornis, Oithona davisae and Acartia tonsa. The kinematics of jumping is similar between the three species. Jumps result in a very erratic translation with no phase of passive coasting and the nauplii move backwards during recovery strokes. This is due to poorly synchronized...... recovery strokes and a low beat frequency relative to the coasting time scale. For the same reason, the propulsion efficiency of the nauplii is low. Given the universality of the nauplius body plan, it is surprising that they seem to be inefficient when jumping, which is different from the very efficient...
Jump point detection for real estate investment success
Hui, Eddie C. M.; Yu, Carisa K. W.; Ip, Wai-Cheung
2010-03-01
In the literature, studies on real estate market were mainly concentrating on the relation between property price and some key factors. The trend of the real estate market is a major concern. It is believed that changes in trend are signified by some jump points in the property price series. Identifying such jump points reveals important findings that enable policy-makers to look forward. However, not all jump points are observable from the plot of the series. This paper looks into the trend and introduces a new approach to the framework for real estate investment success. The main purpose of this paper is to detect jump points in the time series of some housing price indices and stock price index in Hong Kong by applying the wavelet analysis. The detected jump points reflect to some significant political issues and economic collapse. Moreover, the relations among properties of different classes and between stocks and properties are examined. It can be shown from the empirical result that a lead-lag effect happened between the prices of large-size property and those of small/medium-size property. However, there is no apparent relation or consistent lead in terms of change point measure between property price and stock price. This may be due to the fact that globalization effect has more impact on the stock price than the property price.
Vertical jumping tests in volleyball: reliability, validity, and playing-position specifics.
Sattler, Tine; Sekulic, Damir; Hadzic, Vedran; Uljevic, Ognjen; Dervisevic, Edvin
2012-06-01
Vertical jumping is known to be important in volleyball, and jumping performance tests are frequently studied for their reliability and validity. However, most studies concerning jumping in volleyball have dealt with standard rather than sport-specific jumping procedures and tests. The aims of this study, therefore, were (a) to determine the reliability and factorial validity of 2 volleyball-specific jumping tests, the block jump (BJ) test and the attack jump (AJ) test, relative to 2 frequently used and systematically validated jumping tests, the countermovement jump test and the squat jump test and (b) to establish volleyball position-specific differences in the jumping tests and simple anthropometric indices (body height [BH], body weight, and body mass index [BMI]). The BJ was performed from a defensive volleyball position, with the hands positioned in front of the chest. During an AJ, the players used a 2- to 3-step approach and performed a drop jump with an arm swing followed by a quick vertical jump. A total of 95 high-level volleyball players (all men) participated in this study. The reliability of the jumping tests ranged from 0.97 to 0.99 for Cronbach's alpha coefficients, from 0.93 to 0.97 for interitem correlation coefficients and from 2.1 to 2.8 for coefficients of variation. The highest reliability was found for the specific jumping tests. The factor analysis extracted one significant component, and all of the tests were highly intercorrelated. The analysis of variance with post hoc analysis showed significant differences between 5 playing positions in some of the jumping tests. In general, receivers had a greater jumping capacity, followed by libero players. The differences in jumping capacities should be emphasized vis-a-vis differences in the anthropometric measures of players, where middle hitters had higher BH and body weight, followed by opposite hitters and receivers, with no differences in the BMI between positions.
Cushion, Emily J; Goodwin, Jon E; Cleather, Daniel J
2016-05-01
The aim of this study was to determine the mechanical similarity between push jerk (PJ) and jump squat (JS) to countermovement jump (CMJ) and further understand the effect increasing external load may have on this relationship. Eight physically trained men (age 22 ± 3; height 176 ± 7 kg; weight 83 ± 8 kg) performed an unloaded CMJ followed by JS under a range of loads (10, 25, 35, and 50% 1RM back squat) and PJ (30, 50, 65, and 75% 1RM push jerk). A portable force platform and high-speed camera both collecting at 250 Hz were used to establish joint moments and impulse during the propulsive phase of the movements. A standard inverse dynamics model was used to determine joint moment and impulse at the hip, knee, and ankle. Significant correlations (p ≤ 0.05) were shown between CMJ knee joint moment and JS knee joint moment at 25% load and PJ knee joint moment at 30 and 50% load. Significant correlations were also observed between CMJ knee joint impulse and JS knee joint impulse at 10% load and PJ knee joint moment at 30 and 65% load. Significant correlation was also observed between CMJ hip joint impulse and PJ hip joint impulse at 30% load. No significant joint × load interaction was shown as load increased for either PJ or JS. Results from the study suggest partial correspondence between PJ and JS to CMJ, where a greater mechanical similarity was observed between the PJ and CMJ. This interaction is load and joint dependent where lower relative loads showed greatest mechanical similarity. Therefore using lower relative loads when programming may provide a greater transfer of training effect.
Dissipation-Free Jumps for the Magnetosonic Branch of Cold Plasma Motion
International Nuclear Information System (INIS)
Bakholdin, I.B.
2000-01-01
Dissipation-free jumps are studied in a hydrodynamic model of a cold plasma moving at about magnetosonic speed. The jumps described by the generalized Korteweg-de Vries equation, which possesses similar nonlinear and dispersion properties, are considered. In particular, jumps with emission and solitonlike jumps are considered. The assumption that our model possesses jumps of the same type as those for the generalized Korteweg-de Vries equation is justified by numerically investigating the problem of the decay of an initial discontinuity in a cold plasma. An analytic method is described that makes it possible to predict the structure of such jumps in the general case
Dissipative - free jumps for the magnetoacoustic branch of cold plasma motions
International Nuclear Information System (INIS)
Bakholdin, I.B.
2000-01-01
Dissipative-free jumps were studied in hydrodynamic model of cold plasma moving with the rate close to magnetoacoustic one. The jumps for the generalized Korteweg-de Vries equation with similar nonlinear and dispersion properties were studied. Among them there were jumps with emission and solution type jumps. Furthermore, the numerical investigation into the initial break decomposition in cold plasma confirmed the validity of assumption that in the given type of jumps as in case of the generalized Korteweg-de Vries equation. Paper describes the analytical method enabling to forecast the structure nature of such jumps in the general case [ru
International Nuclear Information System (INIS)
Anon.
1990-01-01
The book is on quantum mechanics. The emphasis is on the basic concepts and the methodology. The chapters include: Breakdown of classical concepts; Quantum mechanical concepts; Basic postulates of quantum mechanics; solution of problems in quantum mechanics; Simple harmonic oscillator; and Angular Momentum
International Nuclear Information System (INIS)
Buechler, Hans Peter; Calcarco, Tommaso; Dressel, Martin
2008-01-01
The following topics are dealt with: Artificial atoms and molecules, tailored from solids, fractional flux quanta, molecular magnets, controlled interaction in quantum gases, the theory of quantum correlations in mott matter, cold gases, and mesoscopic systems, Bose-Einstein condensates on the chip, on the route to the quantum computer, a quantum computer in diamond. (HSI)
International Nuclear Information System (INIS)
Reynaud, S.; Giacobino, S.; Zinn-Justin, J.
1997-01-01
This course is dedicated to present in a pedagogical manner the recent developments in peculiar fields concerned by quantum fluctuations: quantum noise in optics, light propagation through dielectric media, sub-Poissonian light generated by lasers and masers, quantum non-demolition measurements, quantum electrodynamics applied to cavities and electrical circuits involving superconducting tunnel junctions. (A.C.)
Lanzagorta, Marco
2011-01-01
This book offers a concise review of quantum radar theory. Our approach is pedagogical, making emphasis on the physics behind the operation of a hypothetical quantum radar. We concentrate our discussion on the two major models proposed to date: interferometric quantum radar and quantum illumination. In addition, this book offers some new results, including an analytical study of quantum interferometry in the X-band radar region with a variety of atmospheric conditions, a derivation of a quantum radar equation, and a discussion of quantum radar jamming.This book assumes the reader is familiar w
Nordic ski jumping injuries. A survey of active American jumpers.
Wright, J R; McIntyre, L; Rand, J J; Hixson, E G
1991-01-01
Little data are available in the medical literature on nordic ski jumping injuries. Injury questionnaires were sent to all active American ski jumpers registered either with the United States Ski Association or with a jumping club registered with the United States Ski Association. One hundred thirty-three of 286 (46.5%) injury questionnaires were returned. Eighty-one of the 133 respondents (60.9%) had been injured sufficiently to require examination by a physician at least once during their jumping careers. This report describes the types and frequencies of injuries sustained by this group of nordic ski jumpers as well as provides demographic data about American ski jumpers. The risk of injury per 100 participant years was 9.4, a rate less than that reported for most high school or college intermural sports.
Dynamical Jumps in a Shape Memory Alloy Oscillator
Directory of Open Access Journals (Sweden)
H. S. Oliveira
2014-01-01
Full Text Available The dynamical response of systems with shape memory alloy (SMA elements presents a rich behavior due to their intrinsic nonlinear characteristic. SMA’s nonlinear response is associated with both adaptive dissipation related to hysteretic behavior and huge changes in properties caused by phase transformations. These characteristics are attracting much technological interest in several scientific and engineering fields, varying from medical to aerospace applications. An important characteristic associated with dynamical response of SMA system is the jump phenomenon. Dynamical jumps result in abrupt changes in system behavior and its analysis is essential for a proper design of SMA systems. This paper discusses the nonlinear dynamics of a one degree of freedom SMA oscillator presenting pseudoelastic behavior and dynamical jumps. Numerical simulations show different aspects of this kind of behavior, illustrating its importance for a proper understanding of nonlinear dynamics of SMA systems.
Hydraulic jumps in a partially filled rotating cylinder
International Nuclear Information System (INIS)
Lundgren, T.S.; Berman, A.S.
1979-06-01
A nonlinear analysis is made of the fluid dynamics of a thin film of liquid completely spun up along the cylindrical wall of a rotating cylinder. The analysis allows for the possibility of hydraulic jumps in the liquid film. Conditions are simulated under which jumps can occur. Under the assumption that synchronous runouts are small relative to the film thickness, a sample calculation of jump position and extent for various operating frequencies is presented. Comparison with experimental observations indicate good qualitative agreement between the analysis and the experiment. Under the additional restriction of constant film thickness and a simple lumped-parameter dynamic model for the rotor and its supports, an analysis is also provided which predicts the amplitude and frequency of the asynchronous runout as a function of operating frequency. A numerical example of the results of such a calculation is provided. 6 figures
Aerodynamic Jump: A Short Range View for Long Rod Projectiles
Directory of Open Access Journals (Sweden)
Mark Bundy
2001-01-01
Full Text Available It is shown that aerodynamic jump for a nonspinning kinetic energy penetrator is not – as conventional definitions may infer – a discontinuous change in the direction of motion at the origin of free flight, nor is it the converse, a cumulative redirection over a domain of infinite extent. Rather, with the aid of an alternative kinematical definition, it is shown that aerodynamic jump for such a projectile is a localized redirection of the center-of-gravity motion, caused by the force of lift due to yaw over the relatively short region from entry into free flight until the yaw reaches its first maximum. A rigorous proof of this statement is provided, but the primary objective of this paper is to provide answers to the questions: what is aerodynamic jump, what does it mean, and what aspects of the flight trajectory does it refer to, or account for.
Adaptive jump barrier height in Monte Carlo configuration kinetics.
Energy Technology Data Exchange (ETDEWEB)
Leitner, Martin; Pfeiler, Wolfgang; Pueschl, Wolfgang [Dynamics of Condensed Systems, Faculty of Physics, University of Vienna, Strudlhofgasse 4, A-1090 Wien (Austria); Vogtenhuber, Doris [Computational Materials Science, Faculty of Physics, University of Vienna, Sensengasse 8, A-1090 Wien (Austria)
2008-07-01
In usual MC simulations of configuration kinetics atom jump probabilities are calculated from energies of the initial and/or final bound states of the moving atom, leaving aside the exact energy of the intermediate saddle point state. This energy may however be critically influenced by the local atomic environment. We propose a strategy to explicitly take account of this influence. The basis is ab initio calculation of representative jump paths in the framework of the nudged elastic band method. From these results, an influence function is derived which modifies the energy of the saddle point and therefore the effective jump barrier height as calculated from the initial and final states according to a cluster expansion scheme. The overall effect is demonstrated on the NiAl system.
Device for investigation of magnetic flux jumps in ribbon superconductors
International Nuclear Information System (INIS)
Andrianov, A.V.; Bashkirov, Yu.A.; Kremlev, M.G.
1986-01-01
A device for simulation of magnetic flux jumps in superconductors of conducting magnet sandwich-type windings super-applyed of a ribbon conductor is described. A superconducting magnet with a measuring cassetter are the main elements of the device. An external magnetic field is generated by a two-sectional superconducting magnet permitting to simulate the shape of the magnetic field characteristic for sandwich-type windings. Maximum radial component of the magnetic field is 2 T. Jumps of the magnetic flux are recorded by induction transducers and the magnetic field-by Hall trasducer. The effect of coating of standard metal on magnetic flux jumps in Nb 3 Sn base superconducting ribbon is considered
AGS tune jump power supply design and test
International Nuclear Information System (INIS)
Mi, J.; Glenn, J.W.; Huang, H.; Marneris, I.; Rosas, P.; Sandberg, J.; Tan, Y.; Zhang, W.
2011-01-01
A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to perform this. The pulsed magnet current ranges from about 140A near injection to about 1400A later. The current pulse rise and fall time are around 100uS and flat tops time is around 4mS. These quadruples have separated supplies. This tune jump pulse power supply employees all semiconductor parts as well as the main switches. During dummy load and magnet testing, the test results showed that the power supply could meet the specification. This article will describe some details of power supply simulation, design and testing. Some test waveforms and pictures are presented in this paper.
Birth-jump processes and application to forest fire spotting.
Hillen, T; Greese, B; Martin, J; de Vries, G
2015-01-01
Birth-jump models are designed to describe population models for which growth and spatial spread cannot be decoupled. A birth-jump model is a nonlinear integro-differential equation. We present two different derivations of this equation, one based on a random walk approach and the other based on a two-compartmental reaction-diffusion model. In the case that the redistribution kernels are highly concentrated, we show that the integro-differential equation can be approximated by a reaction-diffusion equation, in which the proliferation rate contributes to both the diffusion term and the reaction term. We completely solve the corresponding critical domain size problem and the minimal wave speed problem. Birth-jump models can be applied in many areas in mathematical biology. We highlight an application of our results in the context of forest fire spread through spotting. We show that spotting increases the invasion speed of a forest fire front.
A simple method for quantifying jump loads in volleyball athletes.
Charlton, Paula C; Kenneally-Dabrowski, Claire; Sheppard, Jeremy; Spratford, Wayne
2017-03-01
Evaluate the validity of a commercially available wearable device, the Vert, for measuring vertical displacement and jump count in volleyball athletes. Propose a potential method of quantifying external load during training and match play within this population. Validation study. The ability of the Vert device to measure vertical displacement in male, junior elite volleyball athletes was assessed against reference standard laboratory motion analysis. The ability of the Vert device to count jumps during training and match-play was assessed via comparison with retrospective video analysis to determine precision and recall. A method of quantifying external load, known as the load index (LdIx) algorithm was proposed using the product of the jump count and average kinetic energy. Correlation between two separate Vert devices and three-dimensional trajectory data were good to excellent for all jump types performed (r=0.83-0.97), with a mean bias of between 3.57-4.28cm. When matched against jumps identified through video analysis, the Vert demonstrated excellent precision (0.995-1.000) evidenced by a low number of false positives. The number of false negatives identified with the Vert was higher resulting in lower recall values (0.814-0.930). The Vert is a commercially available tool that has potential for measuring vertical displacement and jump count in elite junior volleyball athletes without the need for time-consuming analysis and bespoke software. Subsequently, allowing the collected data to better quantify load using the proposed algorithm (LdIx). Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Kilin, Sergei Ya
1999-01-01
A new research direction known as quantum information is a multidisciplinary subject which involves quantum mechanics, optics, information theory, programming, discrete mathematics, laser physics and spectroscopy, and depends heavily on contributions from such areas as quantum computing, quantum teleportation and quantum cryptography, decoherence studies, and single-molecule and impurity spectroscopy. Some new results achieved in this rapidly growing field are discussed. (reviews of topical problems)
Energy Technology Data Exchange (ETDEWEB)
Kilin, Sergei Ya [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)
1999-05-31
A new research direction known as quantum information is a multidisciplinary subject which involves quantum mechanics, optics, information theory, programming, discrete mathematics, laser physics and spectroscopy, and depends heavily on contributions from such areas as quantum computing, quantum teleportation and quantum cryptography, decoherence studies, and single-molecule and impurity spectroscopy. Some new results achieved in this rapidly growing field are discussed. (reviews of topical problems)
International Nuclear Information System (INIS)
Stapp, H.P.
1988-12-01
Quantum ontologies are conceptions of the constitution of the universe that are compatible with quantum theory. The ontological orientation is contrasted to the pragmatic orientation of science, and reasons are given for considering quantum ontologies both within science, and in broader contexts. The principal quantum ontologies are described and evaluated. Invited paper at conference: Bell's Theorem, Quantum Theory, and Conceptions of the Universe, George Mason University, October 20-21, 1988. 16 refs
Energy Technology Data Exchange (ETDEWEB)
Li, Deyong; Li, Yunliang; Li, Hao; Weng, Yuxiang, E-mail: yxweng@iphy.ac.cn [Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Xianyou [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, Qingxu [School of Physics and Optoelectronic Technology, Dalian University of Technology, No. 2, Linggong Road, Dalian 116023 (China)
2015-05-15
Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm{sup −1} as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10{sup −4} ΔOD for a single wavelength detection, and 2 × 10{sup −4} ΔOD for spectral detection in amide I′ region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.
Overcoming weak intrinsic depolarizing resonances with energy-jump
International Nuclear Information System (INIS)
Huang, H.; Ahrens, L.; Alessi, J.G.
1997-01-01
In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overcome the imperfection depolarizing resonances. Polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. However, significant amount of polarization was lost at 0+ν y , 12+ν y and 36+ν y , which is believed to be partially due to the coupling resonances. To overcome the coupling resonance, an energy-jump was generated by rapidly changing the beam circumference using the powerful AGS rf system. It clearly demonstrates that the novel energy-jump method can successfully overcome coupling resonances and weak intrinsic resonances
Orthogonal Expansions for VIX Options Under Affine Jump Diffusions
DEFF Research Database (Denmark)
Barletta, Andrea; Nicolato, Elisa
2017-01-01
In this work we derive new closed–form pricing formulas for VIX options in the jump-diffusion SVJJ model proposed by Duffie et al. (2000). Our approach is based on the classic methodology of approximating a density function with an orthogonal expansion of polynomials weighted by a kernel. Orthogo......In this work we derive new closed–form pricing formulas for VIX options in the jump-diffusion SVJJ model proposed by Duffie et al. (2000). Our approach is based on the classic methodology of approximating a density function with an orthogonal expansion of polynomials weighted by a kernel...
Heart rate variability as determinism with jump stochastic parameters.
Zheng, Jiongxuan; Skufca, Joseph D; Bollt, Erik M
2013-08-01
We use measured heart rate information (RR intervals) to develop a one-dimensional nonlinear map that describes short term deterministic behavior in the data. Our study suggests that there is a stochastic parameter with persistence which causes the heart rate and rhythm system to wander about a bifurcation point. We propose a modified circle map with a jump process noise term as a model which can qualitatively capture such this behavior of low dimensional transient determinism with occasional (stochastically defined) jumps from one deterministic system to another within a one parameter family of deterministic systems.
Jump Telegraph Processes and Financial Markets with Memory
Directory of Open Access Journals (Sweden)
Nikita Ratanov
2007-01-01
Full Text Available The paper develops a new class of financial market models. These models are based on generalized telegraph processes with alternating velocities and jumps occurring at switching velocities. The model under consideration is arbitrage-free and complete if the directions of jumps in stock prices are in a certain correspondence with their velocity and with the behaviour of the interest rate. A risk-neutral measure and arbitrage-free formulae for a standard call option are constructed. This model has some features of models with memory, but it is more simple.
Pricing Participating Products under a Generalized Jump-Diffusion Model
Directory of Open Access Journals (Sweden)
Tak Kuen Siu
2008-01-01
Full Text Available We propose a model for valuing participating life insurance products under a generalized jump-diffusion model with a Markov-switching compensator. It also nests a number of important and popular models in finance, including the classes of jump-diffusion models and Markovian regime-switching models. The Esscher transform is employed to determine an equivalent martingale measure. Simulation experiments are conducted to illustrate the practical implementation of the model and to highlight some features that can be obtained from our model.
A logarithmic interpretation of Edixhoven's jumps for Jacobians
DEFF Research Database (Denmark)
Eriksson, Dennis; Halle, Lars Halvard; Nicaise, Johannes
2015-01-01
Let A be an abelian variety over a discretely valued field. Edixhoven has defined a filtration on the special fiber of the N\\'eron model of A that measures the behaviour of the N\\'eron model under tame base change. We interpret the jumps in this filtration in terms of lattices of logarithmic...... differential forms in the case where A is the Jacobian of a curve C , and we give a compact explicit formula for the jumps in terms of the combinatorial reduction data of C. ...
Validation of an inertial measurement unit for the measurement of jump count and height.
MacDonald, Kerry; Bahr, Roald; Baltich, Jennifer; Whittaker, Jackie L; Meeuwisse, Willem H
2017-05-01
To validate the use of an inertial measurement unit (IMU) for the collection of total jump count and assess the validity of an IMU for the measurement of jump height against 3-D motion analysis. Cross sectional validation study. 3D motion-capture laboratory and field based settings. Thirteen elite adolescent volleyball players. Participants performed structured drills, played a 4 set volleyball match and performed twelve counter movement jumps. Jump counts from structured drills and match play were validated against visual count from recorded video. Jump height during the counter movement jumps was validated against concurrent 3-D motion-capture data. The IMU device captured more total jumps (1032) than visual inspection (977) during match play. During structured practice, device jump count sensitivity was strong (96.8%) while specificity was perfect (100%). The IMU underestimated jump height compared to 3D motion-capture with mean differences for maximal and submaximal jumps of 2.5 cm (95%CI: 1.3 to 3.8) and 4.1 cm (3.1-5.1), respectively. The IMU offers a valid measuring tool for jump count. Although the IMU underestimates maximal and submaximal jump height, our findings demonstrate its practical utility for field-based measurement of jump load. Copyright © 2016 Elsevier Ltd. All rights reserved.
Quantum Computer Games: Quantum Minesweeper
Gordon, Michal; Gordon, Goren
2010-01-01
The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…
Nikolaidis, Pantelis T; Gkoudas, Konstantinos; Afonso, José; Clemente-Suarez, Vicente J; Knechtle, Beat; Kasabalis, Stavros; Kasabalis, Athanasios; Douda, Helen; Tokmakidis, Savvas; Torres-Luque, Gema
2017-06-01
The aim of the present study was to examine the relationship of vertical jump (Abalakov jump [AJ]) with anthropometric and physiological parameters in youth elite female volleyball players. Seventy-two selected volleyball players from the region of Athens (age 13.3±0.7 years, body mass 62.0±7.2 kg, height 171.5±5.7 cm, body fat 21.2±4.5%), classified into quartiles according to AJ performance (group A, 21.4-26.5 cm; group B, 26.8-29.9 cm; group C, 30.5-33.7 cm; group D, 33.8-45.9 cm), performed a series of physical fitness tests. AJ was correlated with anthropometric (age at peak height velocity [APHV]: r=0.38, Pvolleyball players that jumped the highest were those who matured later than others.
Neuromuscular adaptations to 4 weeks of intensive drop jump training in well-trained athletes
DEFF Research Database (Denmark)
Alkjær, Tine; Meyland, Jacob; Raffalt, Peter C
2013-01-01
This study examined the effects of 4 weeks of intensive drop jump training in well-trained athletes on jumping performance and underlying changes in biomechanics and neuromuscular adaptations. Nine well-trained athletes at high national competition level within sprinting and jumping disciplines...... participated in the study. The training was supervised and augmented feedback on performance was used to ensure maximal training intensity. The drop jumps were performed with minimal contact time and maximal jumping height. Assessment of performance during training showed effects of motor learning. Before...... and after the training intervention maximal isometric muscle strength, the biomechanics, muscle activity pattern of the lower extremities and the soleus H-reflex and V-wave during drop jumping were measured. Maximal jump height and performance index (PI) defined as jumping height divided by contact time...
Afrika Statistika ISSN 2316-090X Jump Resonance in Wind-Felled ...
African Journals Online (AJOL)
jump function. Duffing's model, describing function and Chebyshev polynomials were used .... this study to develop polynomial growth equation for plantains and plantain jump resonance ..... New technologies to increase root health and crop.
Tsoukos, Athanasios; Bogdanis, Gregory C; Terzis, Gerasimos; Veligekas, Panagiotis
2016-08-01
Tsoukos, A, Bogdanis, GC, Terzis, G, and Veligekas, P. Acute improvement of vertical jump performance after isometric squats depends on knee angle and vertical jumping ability. J Strength Cond Res 30(8): 2250-2257, 2016-This study examined the acute effects of maximum isometric squats at 2 different knee angles (90 or 140°) on countermovement jump (CMJ) performance in power athletes. Fourteen national-level male track and field power athletes completed 3 main trials (2 experimental and 1 control) in a randomized and counterbalanced order 1 week apart. Countermovement jump performance was evaluated using a force-plate before and 15 seconds, 3, 6, 9, and 12 minutes after 3 sets of 3 seconds maximum isometric contractions with 1-minute rest in between, from a squat position with knee angle set at 90 or 140°. Countermovement jump performance was improved compared with baseline only in the 140° condition by 3.8 ± 1.2% on the 12th minute of recovery (p = 0.027), whereas there was no change in CMJ height in the 90° condition. In the control condition, there was a decrease in CMJ performance over time, reaching -3.6 ± 1.2% (p = 0.049) after 12 minutes of recovery. To determine the possible effects of baseline jump performance on subsequent CMJ performance, subjects were divided into 2 groups ("high jumpers" and "low jumpers"). The baseline CMJ values of "high jumpers" and "low jumpers" differed significantly (CMJ: 45.1 ± 2.2 vs. 37.1 ± 3.9 cm, respectively, p = 0.001). Countermovement jump was increased only in the "high jumpers" group by 5.4 ± 1.4% (p = 0.001) and 7.4 ± 1.2% (p = 0.001) at the knee angles of 90 and 140°, respectively. This improvement was larger at the 140° angle (p = 0.049). Knee angle during isometric squats and vertical jumping ability are important determinants of the acute CMJ performance increase observed after a conditioning activity.
The prevalence of ski jumping among pupils in the first triad of primary school
Vtič, Maja
2016-01-01
As one of the most widespread sports discipline in Slovenia, ski jumping has a long tradition. Ski jumping is a competitive sport at which recreational engagement is not possible because of its special features and specifics. It is one of the basic sports activities for the development of children's motor skills, since ski jumping requires an integrated training of the trainee. Ski jumping is basically a winter sport, whereas in the summer season, it has also become increasingly present with ...
Nordic ski jumping fatalities in the United States: a 50-year summary.
Wright, J R
1988-06-01
Nordic ski-jumping fatalities are rare events. Six jumping fatalities have occurred in the United States during the past 50 years. The fatality rate for nordic ski jumping, estimated to be roughly 12 fatalities/100,000 participants annually, appears to be within the range of fatality rates for other "risky" outdoor sports. Cervical fractures appear to be the most frequent fatal ski-jumping injury.
Ski jump takeoff performance predictions for a mixed-flow, remote-lift STOVL aircraft
Birckelbaw, Lourdes G.
1992-01-01
A ski jump model was developed to predict ski jump takeoff performance for a short takeoff and vertical landing (STOVL) aircraft. The objective was to verify the model with results from a piloted simulation of a mixed flow, remote lift STOVL aircraft. The prediction model is discussed. The predicted results are compared with the piloted simulation results. The ski jump model can be utilized for basic research of other thrust vectoring STOVL aircraft performing a ski jump takeoff.
Asymptotic Behaviour and Extinction of Delay Lotka-Volterra Model with Jump-Diffusion
Dan Li; Jing’an Cui; Guohua Song
2014-01-01
This paper studies the effect of jump-diffusion random environmental perturbations on the asymptotic behaviour and extinction of Lotka-Volterra population dynamics with delays. The contributions of this paper lie in the following: (a) to consider delay stochastic differential equation with jumps, we introduce a proper initial data space, in which the initial data may be discontinuous function with downward jumps; (b) we show that the delay stochastic differential equation with jumps associate...
Variability of Jump Kinetics Related to Training Load in Elite Female Basketball
Jan Legg; David B. Pyne; Stuart Semple; Nick Ball
2017-01-01
The purpose of this study was to quantify changes in jump performance and variability in elite female basketballers. Junior and senior female representative basketball players (n = 10) aged 18 ± 2 years participated in this study. Countermovement jump (CMJ) data was collected with a Gymaware™ optical encoder at pre-, mid-, and post-season time points across 10 weeks. Jump performance was maintained across the course of the full season (from pre to post). Concentric peak velocity, jump height,...
Energy Technology Data Exchange (ETDEWEB)
Drummond, P D [University of Queensland, St. Lucia, QLD (Australia).Physics Department
1999-07-01
Full text: Quantum optics in Australia has been an active research field for some years. I shall focus on recent developments in quantum and atom optics. Generally, the field as a whole is becoming more and more diverse, as technological developments drive experiments into new areas, and theorists either attempt to explain the new features, or else develop models for even more exotic ideas. The recent developments include quantum solitons, quantum computing, Bose-Einstein condensation, atom lasers, quantum cryptography, and novel tests of quantum mechanics. The talk will briefly cover current progress and outstanding problems in each of these areas. Copyright (1999) Australian Optical Society.
The world price of jump and volatility risk
Driessen, J.J.A.G.; Maenhout, P.
2013-01-01
We study international integration of markets for jump and volatility risk, using index option data for the main global markets. To explain the cross-section of expected option returns we focus on return-based multi-factor models. For each market separately, we provide evidence that volatility and
Motoneuron membrane potentials follow a time inhomogeneous jump diffusion process
DEFF Research Database (Denmark)
Jahn, Patrick; Berg, Rune W; Hounsgaard, Jørn
2011-01-01
models can only be applied over short time windows. However, experimental data show varying time constants, state dependent noise, a graded firing threshold and time-inhomogeneous input. In the present study we build a jump diffusion model that incorporates these features, and introduce a firing...
The Hydraulic Jump: Finding Complexity in Turbulent Water
Vondracek, Mark
2013-01-01
Students who do not progress to more advanced science disciplines in college generally do not realize that seemingly simple physical systems are--when studied in detail--more complex than one might imagine. This article presents one such phenomenon--the hydraulic jump--as a way to help students see the complexity behind the seemingly simple, and…
Berman-Konsowa principle for reversible Markov jump processes
Hollander, den W.Th.F.; Jansen, S.
2013-01-01
In this paper we prove a version of the Berman-Konsowa principle for reversible Markov jump processes on Polish spaces. The Berman-Konsowa principle provides a variational formula for the capacity of a pair of disjoint measurable sets. There are two versions, one involving a class of probability
Jump as Far as You Can [Problem Solvers: Solutions
Yigit, Melike; Bofferding, Laura; Warnock, Miranda
2014-01-01
The How Far Do You Think You Can Jump? activity (see EJ1174770) was completed in three different contexts: an after-school mathematics enrichment program at Woodland and Country Schools in Weston, Massachusetts; a small-group pull-out of second graders at Wren Elementary in Piedmont, South Carolina; and a family math night in Lafayette, Indiana.…
Trading price jump clusters in foreign exchange markets
Czech Academy of Sciences Publication Activity Database
Novotný, Jan; Petrov, D.; Urga, G.
2015-01-01
Roč. 24, June (2015), s. 66-92 ISSN 1386-4181 R&D Projects: GA ČR(CZ) GA14-27047S Institutional support: RVO:67985998 Keywords : price jumps * foreign exchange markets * trading Subject RIV: AH - Economics Impact factor: 1.726, year: 2015
Autotomy, tail regeneration and jumping ability in Cape dwarf ...
African Journals Online (AJOL)
Many studies have examined the effect of caudal autotomy on speed and ... Although longer jumps were less likely to be successful (i.e. the animal ... Their tails may, however, be important to control their landing as well as their locomotion on ...
Structural estimation of jump-diffusion processes in macroeconomics
DEFF Research Database (Denmark)
Posch, Olaf
2009-01-01
This paper shows how to solve and estimate a continuous-time dynamic stochastic general equilibrium (DSGE) model with jumps. It also shows that a continuous-time formulation can make it simpler (relative to its discrete-time version) to compute and estimate the deep parameters using the likelihoo...
Considering Jumping Ship? A Pirate Looks at Retirement
Kilpatrick, Bob G.
2011-01-01
If you're like me, a "senior" faculty member at a public state university facing significant budget cuts, recently you've probably thought about leaving your current position for another faculty position in a different state. A possible reason for considering jumping ship is envisioning a clearer picture of your retirement as it nears on…
Contribution to the experimental study of the hydraulic jump in ...
African Journals Online (AJOL)
The purpose of this study is to study experimentally the hydraulic jump evolving in a symmetric trapezoidal channel with a positive slope, requires the use of an experimental protocol, and to find experimental relations linking the characteristics of the formed projection. The experimental study investigated the variation of the ...
Delayed frost growth on jumping-drop superhydrophobic surfaces.
Boreyko, Jonathan B; Collier, C Patrick
2013-02-26
Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an interdrop frost wave. The growth of this interdrop frost front is shown to be up to 3 times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of interdrop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an interdrop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser minimized frost formation relative to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by limiting the success of interdrop ice bridge formation.
Spatiotemporal characteristics of motor actions by blind long jump athletes.
Torralba, Miguel Angel; Padullés, José María; Losada, Jose Luis; López, Jose Luis
2017-01-01
Blind people depend on spatial and temporal representations to perform activities of daily living and compete in sport. The aim of this study is to determine the spatiotemporal characteristics of long jumps performed by blind athletes and compare findings with those reported for sighted athletes. We analysed a sample of 12 male athletes competing in the F11 Long Jump Finals at the Paralympic Games in London 2012. Performances were recorded using four high-speed cameras, and speeds were measured using a radar speed gun. The images were processed using validated image analysis software. The long jump run-up is shorter in blind athletes than in sighted athletes. We observed statistically significant differences for body centre of mass velocity and an increase in speed over the last three strides prior to take-off, contrasting with reports for sighted athletes and athletes with less severe visual impairment, who maintain or reduce their speed during the last stride. Stride length for the last three strides was the only spatial characteristic that was not significantly associated with effective jump distance. Blind long jumpers extend rather than shorten their last stride. Contact time with the take-off board is longer than that reported for sighted athletes. The actions of blind long jumpers, unlike those without disabilities, do not vary their leg actions during the final runway approach for optimal placement on the take-off board.
Environmentally transmitted parasites: Host-jumping in a heterogeneous environment.
Caraco, Thomas; Cizauskas, Carrie A; Wang, Ing-Nang
2016-05-21
Groups of chronically infected reservoir-hosts contaminate resource patches by shedding a parasite׳s free-living stage. Novel-host groups visit the same patches, where they are exposed to infection. We treat arrival at patches, levels of parasite deposition, and infection of the novel host as stochastic processes, and derive the expected time elapsing until a host-jump (initial infection of a novel host) occurs. At stationarity, mean parasite densities are independent of reservoir-host group size. But within-patch parasite-density variances increase with reservoir group size. The probability of infecting a novel host declines with parasite-density variance; consequently larger reservoir groups extend the mean waiting time for host-jumping. Larger novel-host groups increase the probability of a host-jump during any single patch visit, but also reduce the total number of visits per unit time. Interaction of these effects implies that the waiting time for the first infection increases with the novel-host group size. If the reservoir-host uses resource patches in any non-uniform manner, reduced spatial overlap between host species increases the waiting time for host-jumping. Copyright © 2016 Elsevier Ltd. All rights reserved.
Spatiotemporal characteristics of motor actions by blind long jump athletes
Torralba, Miguel Angel; Padullés, José María; Losada, Jose Luis; López, Jose Luis
2017-01-01
Background Blind people depend on spatial and temporal representations to perform activities of daily living and compete in sport. Objective The aim of this study is to determine the spatiotemporal characteristics of long jumps performed by blind athletes and compare findings with those reported for sighted athletes. Methods We analysed a sample of 12 male athletes competing in the F11 Long Jump Finals at the Paralympic Games in London 2012. Performances were recorded using four high-speed cameras, and speeds were measured using a radar speed gun. The images were processed using validated image analysis software. Results The long jump run-up is shorter in blind athletes than in sighted athletes. We observed statistically significant differences for body centre of mass velocity and an increase in speed over the last three strides prior to take-off, contrasting with reports for sighted athletes and athletes with less severe visual impairment, who maintain or reduce their speed during the last stride. Stride length for the last three strides was the only spatial characteristic that was not significantly associated with effective jump distance. Blind long jumpers extend rather than shorten their last stride. Contact time with the take-off board is longer than that reported for sighted athletes. Conclusion The actions of blind long jumpers, unlike those without disabilities, do not vary their leg actions during the final runway approach for optimal placement on the take-off board. PMID:29018542
Barbara McClintock, Jumping Genes, and Transposition
McClintock Honored * Woman of Science * Educational Material * Resources with Additional Information Barbara McClintock's remarkable life spanned the history of genetics in the twentieth century. ... [T]he science of Dedicate Famous Scientist Stamps ... Woman of Science: McClintock, Barbara and the Jumping Genes, 4,000
RunJumpCode: An Educational Game for Educating Programming
Hinds, Matthew; Baghaei, Nilufar; Ragon, Pedrito; Lambert, Jonathon; Rajakaruna, Tharindu; Houghton, Travers; Dacey, Simon
2017-01-01
Programming promotes critical thinking, problem solving and analytic skills through creating solutions that can solve everyday problems. However, learning programming can be a daunting experience for a lot of students. "RunJumpCode" is an educational 2D platformer video game, designed and developed in Unity, to teach players the…
University–industry collaboration: Jump-starting innovation | IDRC ...
International Development Research Centre (IDRC) Digital Library (Canada)
2010-10-06
Oct 6, 2010 ... In Costa Rica, researchers and business have found innovative ways to ... To jump-start these collaborations, IDRC is supporting research teams in 12 ... steel company recently tried to license a type of steel easy to mould into ...
Plastic strain and flux jumps in hard and composite superconductors
International Nuclear Information System (INIS)
Maksimov, I.L.; Mints, R.G.
1981-01-01
A study is made into the effect of the critical current density dependence upon the value of plastic strain on the critical state stability in hard and composite superconductors under conditions of plastic yield of the material. Criteria of the critical state stability relative to the jointly developing magnetic flux jumps and plastic strain jerks, are found. (author)
The Jump Training Program. In Season Conditioning for Women's Basketball.
Hannam, Sue; And Others
1988-01-01
Women athletes have been successful in maintaining and/or increasing their conditioning and vertical jump levels when they participate in the in-season circuit training program described in this article. An exercise guide, sample individual score card, and photos of women practicing the exercises are included. (IAH)
Kinetics analysis of step and jump forward lunge among badminton ...
African Journals Online (AJOL)
This study was conducted to determine and compare the kinetics during step forward lunge (SFL) and jump forward lunge (JFL) in badminton. Fifteen university badminton players (mean age = 22.07 ± 1.39 years old) were recruited and were assigned to perform SFL and JFL while holding a badminton racquet using their ...
Estimation and prediction under local volatility jump-diffusion model
Kim, Namhyoung; Lee, Younhee
2018-02-01
Volatility is an important factor in operating a company and managing risk. In the portfolio optimization and risk hedging using the option, the value of the option is evaluated using the volatility model. Various attempts have been made to predict option value. Recent studies have shown that stochastic volatility models and jump-diffusion models reflect stock price movements accurately. However, these models have practical limitations. Combining them with the local volatility model, which is widely used among practitioners, may lead to better performance. In this study, we propose a more effective and efficient method of estimating option prices by combining the local volatility model with the jump-diffusion model and apply it using both artificial and actual market data to evaluate its performance. The calibration process for estimating the jump parameters and local volatility surfaces is divided into three stages. We apply the local volatility model, stochastic volatility model, and local volatility jump-diffusion model estimated by the proposed method to KOSPI 200 index option pricing. The proposed method displays good estimation and prediction performance.
The Jumping Ring and Lenz's Law--An Analysis
Bostock-Smith, J. M.
2008-01-01
Lenz's law is sometimes invoked to explain the behaviour of the jumping, or levitating, ring. This is shown to be incomplete, and an alternative explanation using Faraday's laws and circuit analysis is offered. This leads to the choice of optimum material and dimensions for the ring. (Contains 1 table and 4 figures.)
Kinematic Analysis of the Standing Long Jump in Children 6- to 12-Years-Old
Fernandez-Santos, Jorge R.; Gonzalez-Montesinos, Jose Luis; Ruiz, Jonatan R.; Jiménez-Pavón, David; Castro-Piñero, Jose
2018-01-01
The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and…
Walsh, Mark S; Waters, Jeff A; Böhm, Harald; Potteiger, Jeff A
2007-08-01
The purposes of this study are to examine gender differences in the contribution of the arm swing to jump height in men and women basketball players and to examine the role of upper-body strength in the contribution of arm swing to jump height. National Collegiate Athletic Association Division I basketball players (men n = 13, women n = 12) performed 4 jumping movements: squat jumps with hands on hips (SNA) and with arm swings (SA) and countermovement jumps with hands on hips and with arm swings (CMA). Differences were found between the jump heights of men and women. Use of the arms increased the jump height of men more than women. Compared with the SNA, the SA allowed an increase of 7 cm (23%) for men and 4 cm (17%) for women. The CMA allowed for an increase of 10 cm (30%) for men and 6 cm (24%) for women. General upper-body strength measures did not correlate strongly with the effect of arms on jumping, but peak power did. As in previous studies, peak power had a high correlation with jumping performance. These results show that the arm swing contributes significantly to jump performance in both men and women basketball players and that strength training for jumping should focus on power production and lifting exercises that are jump specific.
Effect of a neuromuscular training program on the kinetics and kinematics of jumping tasks.
Chappell, Jonathan D; Limpisvasti, Orr
2008-06-01
Altered motor control strategies are a proposed cause of the female athlete's increased risk for noncontact anterior cruciate ligament injury. Injury prevention programs have shown promising results in decreasing the incidence of anterior cruciate ligament injury. To evaluate the effect of the Kerlan-Jobe Orthopaedic Clinic Modified Neuromuscular Training Program on the biomechanics of select jumping tasks in the female collegiate athlete. Controlled laboratory study. Thirty female National Collegiate Athletic Association Division I soccer and basketball players performed vertical jump, hopping tests, and 2 jumping tasks (drop jump and stop jump). All subjects completed a 6-week neuromuscular training program with core strengthening and plyometric training. Three-dimensional motion analysis and force plate data were used to compare the kinetics and kinematics of jumping tasks before and after training. Dynamic knee valgus moment during the stance phase of stop jump tasks decreased after completion of the neuromuscular training program (P = .04), but differences were not observed for the drop jump. Initial knee flexion (P = .003) and maximum knee flexion (P = .006) angles increased during the stance phase of drop jumps after training, but differences were not observed for the stop jump. The athletes showed improved performance in vertical jump (P training program improved select athletic performance measures and changed movement patterns during jumping tasks in the subject population. The use of this neuromuscular training program could potentially modify the collegiate athlete's motion strategies, improve performance, and lower the athlete's risk for injury.
ELEMENTS OF KINEMATICS SPECIFIC TO THE JUMP OF THE MALE TRIPLE JUMP EVENT
Directory of Open Access Journals (Sweden)
MIHAI ILIE
2010-12-01
Full Text Available The quality of results obtained in competitions is based on the use of the most efficient technologies and conducting systems in the sportive training process, all embedded in operational strategies to enable the efficient filtering of the information exchange between coaches and athletes in order to ensure all the resources needed for an optimal monitoring and conveyance training process. The purpose of this study was to examine the kinematic point of view the main technical aspects of specific proof of triple last step - the long jump. Research was conducted on athletes who specialize in thissample, and components of the National Olympic Lot Romanian Athletics Federation. Using kinematic analysis software movement - Dartfish © I obtained a series of kinematic parameters (time, position, angles discussed specific issues in research, processing and interpretation leading to the general conclusion according to which: kinematic analysis of the key features approach specific technical triple last step of the sample by use of IT leads to useful information specific to this test in monitoring technique
Jumping for recognition: Women's ski jumping viewed as a struggle for rights.
Andersen, W; Loland, S
2017-03-01
With the campaign for women's participation in international and Olympic ski jumping as a practical case, sport's potential for recognition of individual rights is explored. In line with Honneth's influential ethical theory, recognition of rights refers to a mutual recognition between persons of each other as rational and responsible agents with an equal right to take part in the public formation and development of their community or practice. The argument is that women ski jumpers were entitled to compete as they had actual and/or potential capabilities and skills to contribute in the public formation and development of their sport. Their exclusion was a violation of individual rights. At a more general level, sport is discussed as a sphere for recognition of rights. It is argued that the basic principles of equal opportunity to take part and to perform make sport a particularly clear and potent sphere for such recognition, and also for the identification of rights violations. In sport, rights, or the violation of rights, are demonstrated in concrete and embodied ways. It is concluded that struggles for recognition and individual rights are a continuous process in sport as in most other human institutions and practices. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Quantum entanglement and quantum teleportation
International Nuclear Information System (INIS)
Shih, Y.H.
2001-01-01
One of the most surprising consequences of quantum mechanics is the entanglement of two or more distance particles. The ''ghost'' interference and the ''ghost'' image experiments demonstrated the astonishing nonlocal behavior of an entangled photon pair. Even though we still have questions in regard to fundamental issues of the entangled quantum systems, quantum entanglement has started to play important roles in quantum information and quantum computation. Quantum teleportation is one of the hot topics. We have demonstrated a quantum teleportation experiment recently. The experimental results proved the working principle of irreversibly teleporting an unknown arbitrary quantum state from one system to another distant system by disassembling into and then later reconstructing from purely classical information and nonclassical EPR correlations. The distinct feature of this experiment is that the complete set of Bell states can be distinguished in the Bell state measurement. Teleportation of a quantum state can thus occur with certainty in principle. (orig.)
Jumping-droplet electronics hot-spot cooling
International Nuclear Information System (INIS)
Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle
2017-01-01
Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm x 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25°C air temperature, 20-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm), and heat flux (demonstrated to 13 W/cm"2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈ 200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm"2. Finally, this work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.
Jumping-droplet electronics hot-spot cooling
Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle; Neely, Jason; Pilawa-Podgurski, Robert C. N.; Miljkovic, Nenad
2017-03-01
Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm × 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25 °C air temperature, 20%-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm) and applied heat flux (demonstrated to 13 W/cm2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm2. This work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.
Kaçal, Mustafa Recep; Han, İbrahim; Akman, Ferdi
2015-01-01
Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature. Copyright © 2014 Elsevier Ltd. All rights reserved.
Quantum robots and quantum computers
Energy Technology Data Exchange (ETDEWEB)
Benioff, P.
1998-07-01
Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.
Quantum computers and quantum computations
International Nuclear Information System (INIS)
Valiev, Kamil' A
2005-01-01
This review outlines the principles of operation of quantum computers and their elements. The theory of ideal computers that do not interact with the environment and are immune to quantum decohering processes is presented. Decohering processes in quantum computers are investigated. The review considers methods for correcting quantum computing errors arising from the decoherence of the state of the quantum computer, as well as possible methods for the suppression of the decohering processes. A brief enumeration of proposed quantum computer realizations concludes the review. (reviews of topical problems)
Thomas, Brandon J; Hawkins, Matthew M; Nalepka, Patrick
2017-03-30
Runeson (Scandanavian Journal of Psychology 18:172-179, 1977) suggested that the polar planimeter might serve as an informative model system of perceptual mechanism. The key aspect of the polar planimeter is that it registers a higher order property of the environment without computational mediation on the basis of lower order properties, detecting task-specific information only. This aspect was posited as a hypothesis for the perception of jumping and reaching affordances for the self and another person. The findings supported this hypothesis. The perception of reaching while jumping significantly differed from an additive combination of jump-without-reaching and reach-without-jumping perception. The results are consistent with Gibson's (The senses considered as perceptual systems, Houghton Mifflin, Boston, MA; Gibson, The senses considered as perceptual systems, Houghton Mifflin, Boston, MA, 1966; The ecological approach to visual perception, Houghton Mifflin, Boston, MA; Gibson, The ecological approach to visual perception, Houghton Mifflin, Boston, MA, 1979) theory of information-that aspects of the environment are specified by patterns in energetic media.
Chanda, Rajat
1997-01-01
The book discusses the laws of quantum mechanics, several amazing quantum phenomena and some recent progress in understanding the connection between the quantum and the classical worlds. We show how paradoxes arise and how to resolve them. The significance of Bell's theorem and the remarkable experimental results on particle correlations are described in some detail. Finally, the current status of our understanding of quantum theory is summerised.
Delayed feedback control in quantum transport.
Emary, Clive
2013-09-28
Feedback control in quantum transport has been predicted to give rise to several interesting effects, among them quantum state stabilization and the realization of a mesoscopic Maxwell's daemon. These results were derived under the assumption that control operations on the system are affected instantaneously after the measurement of electronic jumps through it. In this contribution, I describe how to include a delay between detection and control operation in the master equation theory of feedback-controlled quantum transport. I investigate the consequences of delay for the state stabilization and Maxwell's daemon schemes. Furthermore, I describe how delay can be used as a tool to probe coherent oscillations of electrons within a transport system and how this formalism can be used to model finite detector bandwidth.
Oranchuk, Dustin J; Robinson, Tracey L; Switaj, Zachary J; Drinkwater, Eric J
2017-04-15
Weightlifting movements have high skill demands and require expert coaching. Loaded jumps have a comparably lower skill demand, but may be similarly effective for improving explosive performance. The purpose of this study was to compare vertical jump performance, isometric force, and rate of force development (RFD) following a ten-week intervention employing the hang high-pull (hang-pull) or trap-bar jump squat (jump-squat). Eighteen NCAA Division II swimmers (8 males, 10 females) with at least one year of resistance training experience volunteered to participate. Testing included the squat jump (SJ), countermovement jump (CMJ) and the isometric mid-thigh pull (IMTP). Vertical ground reaction forces were analyzed to obtain jump height and relative peak power. Relative peak force, peak RFD and relative force at five time bands were obtained from the IMTP. Subjects were randomly assigned to either a hang-pull (n = 9) or jump-squat (n = 9) training group and completed a ten-week, volume-equated, periodized training program. While there was a significant main effect of training for both groups, no statistically significant between-group differences were found (p ≥ 0.17) for any of the dependent variables. However, medium effect sizes in favor of the jump-squat training group were seen in SJ height (d = 0.56) and SJ peak power (d = 0.69). Loaded jumps seem equally effective as weightlifting derivatives for improving lower-body power in experienced athletes. Since loaded jumps require less skill and less coaching expertise than weightlifting, loaded jumps should be considered where coaching complex movements is difficult.
Laudner, Kevin; Evans, Daniel; Wong, Regan; Allen, Aaron; Kirsch, Tom; Long, Brian; Meister, Keith
2015-06-01
Clinicians are often challenged when making return-to-play decisions following anterior cruciate ligament reconstruction (ACL-R). Isokinetic strength and jump performance testing are common tools used to make this decision. Unfortunately, vertical jump performance standards have not been clearly established and many clinicians do not have access to isokinetic testing equipment. To establish normative jump and strength characteristics in ACL-R patients cleared by an orthopedic physician to return-to-play and to determine if relationships exist between knee isokinetic strength measurements and jump characteristics described using an electronic jump map system. Descriptive laboratory study. Thirty-three ACL-R patients who had been cleared to return to athletic competition participated in this study. Twenty-six of these ACL-R participants were also matched to 26 asymptomatic athletes based on sex, limb, height, and mass to determine isokinetic strength and jump characteristic differences between groups. Jump tests consisted of single leg vertical, double leg vertical, and a 4-jump single leg vertical jump assessed using an electronic jump mat system. Independent t-tests were used to determine differences between groups and multiple regression analyses were used to identify any relationships between jump performance and knee strength (pjump capabilities and some bilateral knee strength deficiencies compared to the matched control group. The ACL-R group also showed several moderate-to-strong positive relationships for both knee extension and flexion strength with several jump performance characteristics, such as single and double leg vertical jump height. The current results indicate that ACL-R patients present with several knee strength and vertical jump differences compared to a matched control group at the time of return-to-play. Also, ACL-R patient's performance on an electronic jump mat system is strongly related to isokinetic knee strength measures. 2b.
Coleman, Piers; Schofield, Andrew J
2005-01-20
As we mark the centenary of Albert Einstein's seminal contribution to both quantum mechanics and special relativity, we approach another anniversary--that of Einstein's foundation of the quantum theory of solids. But 100 years on, the same experimental measurement that puzzled Einstein and his contemporaries is forcing us to question our understanding of how quantum matter transforms at ultra-low temperatures.
Indian Academy of Sciences (India)
In the first part of this article, we had looked at how quantum physics can be harnessed to make the building blocks of a quantum computer. In this concluding part, we look at algorithms which can exploit the power of this computational device, and some practical difficulties in building such a device. Quantum Algorithms.
I, Quantum Robot: Quantum Mind control on a Quantum Computer
Zizzi, Paola
2008-01-01
The logic which describes quantum robots is not orthodox quantum logic, but a deductive calculus which reproduces the quantum tasks (computational processes, and actions) taking into account quantum superposition and quantum entanglement. A way toward the realization of intelligent quantum robots is to adopt a quantum metalanguage to control quantum robots. A physical implementation of a quantum metalanguage might be the use of coherent states in brain signals.
Marián, Vanderka; Katarína, Longová; Dávid, Olasz; Matúš, Krčmár; Simon, Walker
2016-01-01
The purpose of the study was to determine the effects of 8 weeks of jump squat training on isometric half squat maximal force production (Fmax) and rate of force development over 100ms (RFD100), countermovement jump (CMJ) and squat jump (SJ) height, and 50 m sprint time in moderately trained men. Sixty eight subjects (~21 years, ~180 cm, ~75 kg) were divided into experimental (EXP; n = 36) and control (CON, n = 32) groups. Tests were completed pre-, mid- and post-training. EXP performed jump squat training 3 times per week using loads that allowed all repetitions to be performed with ≥90% of maximum average power output (13 sessions with 4 sets of 8 repetitions and 13 sessions with 8 sets of 4 repetitions). Subjects were given real-time feedback for every repetition during the training sessions. Significant improvements in Fmax from pre- to mid- (Δ ~14%, psquats with loads that allow repetitions to be performed ≥90% of maximum average power output can simultaneously improve several different athletic performance tasks in the short-term. Key points Jump squat exercise is one of many exercises to develop explosive strength that has been the focus of several researches, while the load used during the training seem to be an important factor that affects training outcomes. Experimental group improved performance in all assessed parameters, such as Fmax, RFD100, CMJ, SJ and 50 m sprint time. However, improvements in CMJ and SJ were recorded after the entire power training period and thereafter plateau occurred. The portable FitroDyne could serve as a valuable device to individualize the load that maximizes mean power output and visual feedback can be provided to athletes during the training. PMID:27803628
Entanglement evolution for quantum trajectories
International Nuclear Information System (INIS)
Vogelsberger, S; Spehner, D
2011-01-01
Entanglement is a key resource in quantum information. It can be destroyed or sometimes created by interactions with a reservoir. In recent years, much attention has been devoted to the phenomena of entanglement sudden death and sudden birth, i.e., the sudden disappearance or revival of entanglement at finite times resulting from a coupling of the quantum system to its environment. We investigate the evolution of the entanglement of noninteracting qubits coupled to reservoirs under monitoring of the reservoirs by means of continuous measurements. Because of these measurements, the qubits remain at all times in a pure state, which evolves randomly. To each measurement result (or 'realization') corresponds a quantum trajectory in the Hilbert space of the qubits. We show that for two qubits coupled to independent baths subjected to local measurements, the average of the qubits' concurrence over all quantum trajectories is either constant or decays exponentially. The corresponding decay rate depends on the measurement scheme only. This result contrasts with the entanglement sudden death phenomenon exhibited by the qubits' density matrix in the absence of measurements. Our analysis applies to arbitrary quantum jump dynamics (photon counting) as well as to quantum state diffusion (homodyne or heterodyne detections) in the Markov limit. We discuss the best measurement schemes to protect the entanglement of the qubits. We also analyze the case of two qubits coupled to a common bath. Then, the average concurrence can vanish at discrete times and may coincide with the concurrence of the density matrix. The results explained in this article have been presented during the 'Fifth International Workshop DICE2010' by the first author and have been the subject of a prior publication.
Modeling and forecasting electricity price jumps in the Nord Pool power market
DEFF Research Database (Denmark)
Knapik, Oskar
extreme prices and forecasting of the price jumps is crucial for risk management and market design. In this paper, we consider the problem of the impact of fundamental price drivers on forecasting of price jumps in NordPool intraday market. We develop categorical time series models which take into account......For risk management traders in the electricity market are mainly interested in the risk of negative (drops) or of positive (spikes) price jumps, i.e. the sellers face the risk of negative price jumps while the buyers face the risk of positive price jumps. Understanding the mechanism that drive...
Time in quantum mechanics. Vol. 1. 2. ed.
International Nuclear Information System (INIS)
Muga, J.G.; Sala Mayato, R.; Egusquiza, I.L.
2008-01-01
The treatment of time in quantum mechanics is still an important and challenging open question in the foundation of the quantum theory. This book describes the problems, and the attempts and achievements in defining, formalizing and measuring different time quantities in quantum theory, such as the parametric (clock) time, tunneling times, decay times, dwell times, delay times, arrival times or jump times. This multi-authored book, written as an introductory guide for newcomers to the subject, as well as a useful source of information for the expert, covers many of the open questions. After the brief historical overview in the introduction, 12 contributions are devoted to conceptual and theoretical investigations as well as experimental issues in quantum-mechanical time measurements. This novel monograph should attract physicists as well as philosophers of science working in the foundations of quantum physics. For this revised second edition, all chapters have been updated and extended where appropriate. (orig.)
Quantum Logic and Quantum Reconstruction
Stairs, Allen
2015-01-01
Quantum logic understood as a reconstruction program had real successes and genuine limitations. This paper offers a synopsis of both and suggests a way of seeing quantum logic in a larger, still thriving context.
Quantum dynamics of quantum bits
International Nuclear Information System (INIS)
Nguyen, Bich Ha
2011-01-01
The theory of coherent oscillations of the matrix elements of the density matrix of the two-state system as a quantum bit is presented. Different calculation methods are elaborated in the case of a free quantum bit. Then the most appropriate methods are applied to the study of the density matrices of the quantum bits interacting with a classical pumping radiation field as well as with the quantum electromagnetic field in a single-mode microcavity. The theory of decoherence of a quantum bit in Markovian approximation is presented. The decoherence of a quantum bit interacting with monoenergetic photons in a microcavity is also discussed. The content of the present work can be considered as an introduction to the study of the quantum dynamics of quantum bits. (review)
Effect of cluster sets on plyometric jump power.
Moreno, Steven D; Brown, Lee E; Coburn, Jared W; Judelson, Daniel A
2014-09-01
Cluster sets may lead to enhanced power (PW) production by allowing for partial recovery. The purpose of this study was to determine the effects of cluster sets vs. traditional sets on plyometric jump PW, ground reaction force, take-off velocity (TOV), and jump height (JH). Twenty-six recreationally trained college men completed 3 testing sessions, which involved performing repeated body-weight (BW) plyometric squat jumps across 3 different set configurations: traditional (2 sets of 10 with 90-second rest between sets), cluster 1 (4 sets of 5 with 30-second rest between sets), and cluster 2 (10 sets of 2 with 10-second rest between sets). Ground reaction force results demonstrated no interaction or main effect for condition, but there was a significant (p ≤ 0.05) main effect for repetition, where repetition 1 was significantly less than repetitions 3-5, 7-10, 12-15, and 17-20. For TOV, PW, and JH, there were significant interactions. Take-off velocity resulted in the following: Traditional, repetition 1 was significantly greater than repetitions 7-10 and 17-20, but was significantly less than repetition 13; cluster 1, repetition 1 was significantly less than repetitions 2-5; and cluster 2, there were no significant differences. Power resulted in the following: Traditional, repetition 1 was significantly greater than repetitions 4-10 and 14-20; cluster 1, repetition 1 was significantly greater than repetitions 7-10 and 12-20; and cluster 2, repetition 1 was significantly greater than repetitions 3, 6-18, and 20. Jump height resulted in the following: Traditional, repetition 1 was significantly greater than repetitions 18-20, but was significantly less than repetitions 3 and 13. For cluster 1 and cluster 2, there were no significant differences. These results demonstrate that cluster sets, specifically 10 sets of 2, allow for a greater maintenance of PW, TOV, and JH compared with a traditional 2 sets of 10 when performing repeated BW plyometric squat jumps. A lack
EFFECT OF DIFFERENT STRETCHING PROTOCOLS ON VERTICAL JUMP PERFORMANCE
Directory of Open Access Journals (Sweden)
Emre Serin
2018-04-01
Full Text Available This study aimed to examine the effect of different stretching exercises on vertical jump performance. A total of 14 national male athletes sporting in the elite level took part in the study. The age average of the participants was 20.25±1.03 year, the average height was 1.80±.08 m, the average body weight was 77.14±18.91 kg, average of sporting age was 9.87±3.31 year and the average number of participation in international games was 10.0±3.31. As stretching protocol: Method 1 (5 minutes of jogging and 2 minutes of active rest followed by Method 2 (static stretching for 4 different muscle groups 3 repetitions for 15 seconds of static stretching, rest for 10 seconds between groups and then consecutively, Method 3 (Dynamic stretching exercises with 3 repetitions for 15 seconds and 10 seconds rest between different muscle groups were applied in the study. The vertical jump performance before and after different stretching exercises of the participants was determined by means of the vertical jump test using the smart speed lite system. Before and after the training of all athletes, HR was recorded with a heart rate monitor (RS 800, Polar Vantage NV, Polar Electro Oy, Finland with 5 seconds intervals. Before the study, the chest band of the heartbeat monitor was placed on the chest of the athlete and the HR was recorded from the monitor. SPSS 15.0 statistical package program was used for evaluation and calculation of the data. In this study in addition to descriptive statistics (mean and standard deviation paired samples t-test was used to determine the difference between the vertical jump performance of the participants before and after different stretching exercises. As a result, this study showed that; applying the dynamic and static stretching exercises consecutively affected the vertical jump performance 4.5 cm positively (p<.05. It is suggested that different dynamic and static stretching exercises should be included in the vertical jump.
Judge, L W; Burke, J R
2015-06-01
The purpose of the study was to describe changes in the excitability of the stretch reflex response (SRR) during different drop jumps as a function of training background and as an adaptation to a preseason sport-specific resistance training program. Twelve collegiate field event athletes (discus, hammer, javelin, shot put, and weight; 9 males and 3 females) and 12 college-aged control subjects performed the following three jumps: (1) countermovement jump (CMJ); (2) countermovement drop jump; and (3) bounce-drop jump (BDJ). Neuromechanical changes in the performance of drop jumps by athletes were measured during the sport-specific resistance training program. Pre-post testing of drop jump performance by control subjects was included for comparison. For each jump trial, ground reaction forces (GRF), electromyograms (EMG) and cinematographic data were collected. There were no training adaptations. However, jump heights were greater for the athletes than the controls among the different jumps with the jump heights for all subjects being less during the BDJ than CMJ and CDJ. In athletes only, there was a differential modulation of the SRR from the gastrocnemius muscle with different levels of background muscle activity for the CDJ and BDJ. There were changes in excitability of SRR from the gastrocnemius muscle as a function of training background. Interrelated neuromechanical mechanisms to include landing biomechanics, intrinsic musculotendinous tissue properties of the ankle, and centrally regulated motor commands may underlie the facilitation of the SRR from the gastrocnemius muscle in athletes as compared to controls.
Brown, Matthew J.
2014-02-01
The framework of quantum frames can help unravel some of the interpretive difficulties i the foundation of quantum mechanics. In this paper, I begin by tracing the origins of this concept in Bohr's discussion of quantum theory and his theory of complementarity. Engaging with various interpreters and followers of Bohr, I argue that the correct account of quantum frames must be extended beyond literal space-time reference frames to frames defined by relations between a quantum system and the exosystem or external physical frame, of which measurement contexts are a particularly important example. This approach provides superior solutions to key EPR-type measurement and locality paradoxes.
Zurek, Wojciech Hubert
2009-03-01
Quantum Darwinism describes the proliferation, in the environment, of multiple records of selected states of a quantum system. It explains how the quantum fragility of a state of a single quantum system can lead to the classical robustness of states in their correlated multitude; shows how effective `wave-packet collapse' arises as a result of the proliferation throughout the environment of imprints of the state of the system; and provides a framework for the derivation of Born's rule, which relates the probabilities of detecting states to their amplitudes. Taken together, these three advances mark considerable progress towards settling the quantum measurement problem.
An algorithm to remove fringe jumps and its application to microwave reflectometry
International Nuclear Information System (INIS)
Ejiri, A.; Kawahata, K.; Shinohara, K.
1997-01-01
In some plasma discharges, the phase measured by microwave reflectometry has many fringe (2π radians) jumps. A new algorithm to detect and remove fringe jumps has been developed, and applied to the data in the JIPP TII-U tokamak. Using this algorithm, quantitative properties of fringe jumps, and their effects on the analysis of phase fluctuations are investigated. It was found that the occurrence of fringe jumps obeys a Poisson process, and the time scale of jumps is distributed over a wide range. Fringe jumps affect mainly the low-frequency components of phase fluctuations. Comparison of the phase corrected by the algorithm and the phase calculated from the time smoothed signals indicates that time smoothing (or frequency filtering) is an effective way to obtain information concerning the macroscopic density profile. Fringe jump and phase runaway can be phenomenologically explained by the distribution of the complex amplitude of the reflected wave. (author)
Vertical jump fatigue does not affect intersegmental coordination and segmental contribution
Directory of Open Access Journals (Sweden)
Gleber Pereira
2014-09-01
Full Text Available The aim of this study was to describe the intersegmental coordination and segmental contribution during intermittent vertical jumps performed until fatigue. Seven male visited the laboratory on two occasions: 1 the maximum vertical jump height was determined followed by vertical jumps habituation; 2 participants performed intermittent countermovement jumps until fatigue. Kinematic and kinetic variables were recorded. The overall reduction in vertical jump height was 5,5%, while the movement duration increased 10% during the test. The thigh segment angle at movement reversal significantly increased as the exercise progressed. Non-significant effect of fatigue on movement synergy was found for the intersegmental coordination pattern. More than 90% of the intersegmental coordination was explained by one coordination pattern. Thigh rotation contributed the most to the intersegmental coordination pattern, with the trunk second and the shank the least. Therefore, one intersegmental coordination pattern is followed throughout the vertical jumps until fatigue and thigh rotation contributes the most to jump height.
Dynamic Jump Intensities and Risk Premiums in Crude Oil Futures and Options Markets
DEFF Research Database (Denmark)
Christoffersen, Peter; Jacobs, Kris; Li, Bingxin
2016-01-01
Options on crude oil futures are the most actively traded commodity options. We develop a class of computationally efficient discrete-time jump models that allow for closed-form option valuation, and we use crude oil futures and options data to investigate the economic importance of jumps...... and dynamic jump intensities in these markets. Allowing for jumps is crucial for modeling crude oil futures and futures options, and we find evidence in favor of time-varying jump intensities. During crisis periods, jumps occur more frequently. The properties of the jump processes implied by the option data...... differ from those implied by the futures data, which may be due to improved parameter identification....
International Nuclear Information System (INIS)
Kouwenhoven, L.; Marcus, C.
1998-01-01
Quantum dots are man-made ''droplets'' of charge that can contain anything from a single electron to a collection of several thousand. Their typical dimensions range from nanometres to a few microns, and their size, shape and interactions can be precisely controlled through the use of advanced nanofabrication technology. The physics of quantum dots shows many parallels with the behaviour of naturally occurring quantum systems in atomic and nuclear physics. Indeed, quantum dots exemplify an important trend in condensed-matter physics in which researchers study man-made objects rather than real atoms or nuclei. As in an atom, the energy levels in a quantum dot become quantized due to the confinement of electrons. With quantum dots, however, an experimentalist can scan through the entire periodic table by simply changing a voltage. In this article the authors describe how quantum dots make it possible to explore new physics in regimes that cannot otherwise be accessed in the laboratory. (UK)
Validity Study of a Jump Mat Compared to the Reference Standard Force Plate.
Rogan, Slavko; Radlinger, Lorenz; Imhasly, Caroline; Kneubuehler, Andrea; Hilfiker, Roger
2015-12-01
In the field of vertical jump diagnostics, force plates (FP) are the reference standard. Recently, despite a lack of evidence, jump mats have been used increasingly. Important factors in favor of jumping mats are their low cost and portability. This validity study compared the Haynl-Elektronik jump mat (HE jump mat) with the reference standard force plate. Ten healthy volunteers participated and each participant completed three series of five drop jumps (DJ). The parameters ground contact time (GCT) and vertical jump height (VJH) from the HE jump mat and the FP were used to evaluate the concurrent validity. The following statistical calculations were performed: Pearson's correlation (r), Bland-Altman plots (standard and for adjusted trend), and regression equations. The Bland-Altman plots suggest that the HE jump mat measures shorter contact times and higher jump heights than the FP. The trend-adjusted Bland-Altman plot shows higher mean differences and wider wing-spreads of confidence limits during longer GCT. During the VJH the mean differences and the wing-spreads of the confidence limits throughout the range present as relatively constant. The following regression equations were created, as close as possible to the true value: GCT = 5.920385 + 1.072293 × [value HE jump mat] and VJH = -1.73777 + 1.011156 × [value HE jump mat]. The HE jump mat can be recommended in relation to the validity of constraints. In this study, only a part of the quality criteria were examined. For the final recommendation it is advised to examine the HE jump mat on the other quality criteria (test-retest reliability, sensitivity change).
Keeping Your Eye on the Rail: Gaze Behaviour of Horse Riders Approaching a Jump
Hall, Carol; Varley, Ian; Kay, Rachel; Crundall, David
2014-01-01
The gaze behaviour of riders during their approach to a jump was investigated using a mobile eye tracking device (ASL Mobile Eye). The timing, frequency and duration of fixations on the jump and the percentage of time when their point of gaze (POG) was located elsewhere were assessed. Fixations were identified when the POG remained on the jump for 100 ms or longer. The jumping skill of experienced but non-elite riders (n = 10) was assessed by means of a questionnaire. Their gaze behaviour was recorded as they completed a course of three identical jumps five times. The speed and timing of the approach was calculated. Gaze behaviour throughout the overall approach and during the last five strides before take-off was assessed following frame-by-frame analyses. Differences in relation to both round and jump number were found. Significantly longer was spent fixated on the jump during round 2, both during the overall approach and during the last five strides (pJump 1 was fixated on significantly earlier and more frequently than jump 2 or 3 (pjump 3 than with jump 1 (p = 0.01) but there was no difference in errors made between rounds. Although no significant correlations between gaze behaviour and skill scores were found, the riders who scored higher for jumping skill tended to fixate on the jump earlier (p = 0.07), when the horse was further from the jump (p = 0.09) and their first fixation on the jump was of a longer duration (p = 0.06). Trials with elite riders are now needed to further identify sport-specific visual skills and their relationship with performance. Visual training should be included in preparation for equestrian sports participation, the positive impact of which has been clearly demonstrated in other sports. PMID:24846055
Skazalski, C; Whiteley, R; Hansen, C; Bahr, R
2018-05-01
Use of a commercially available wearable device to monitor jump load with elite volleyball players has become common practice. The purpose of this study was to evaluate the validity and reliability of this device, the Vert, to count jumps and measure jump height with professional volleyball players. Jump count accuracy was determined by comparing jumps recorded by the device to jumps observed through systematic video analysis of three practice sessions and two league matches performed by a men's professional volleyball team. Jumps performed by 14 players were each coded for time and jump type and individually matched to device recorded jumps. Jump height validity of the device was examined against reference standards as participants performed countermovement jumps on a force plate and volleyball-specific jumps with a Vertec. The Vert device accurately counted 99.3% of the 3637 jumps performed during practice and match play. The device showed excellent jump height interdevice reliability for two devices placed in the same pouch during volleyball jumps (r = .99, 95% CI 0.98-0.99). The device had a minimum detectable change (MDC) of 9.7 cm and overestimated jump height by an average of 5.5 cm (95% CI 4.5-6.5) across all volleyball jumps. The Vert device demonstrates excellent accuracy counting volleyball-specific jumps during training and competition. While the device is not recommended to measure maximal jumping ability when precision is needed, it provides an acceptable measure of on-court jump height that can be used to monitor athlete jump load. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Quantum information. Teleporation - cryptography - quantum computer
International Nuclear Information System (INIS)
Breuer, Reinhard
2010-01-01
The following topics are dealt with: Reality in the test house, quantum teleportation, 100 years of quantum theory, the reality of quanta, interactionless quantum measurement, rules for quantum computers, quantum computers with ions, spintronics with diamond, the limits of the quantum computers, a view into the future of quantum optics. (HSI)
Quantum symmetry in quantum theory
International Nuclear Information System (INIS)
Schomerus, V.
1993-02-01
Symmetry concepts have always been of great importance for physical problems like explicit calculations, classification or model building. More recently, new 'quantum symmetries' ((quasi) quantum groups) attracted much interest in quantum theory. It is shown that all these quantum symmetries permit a conventional formulation as symmetry in quantum mechanics. Symmetry transformations can act on the Hilbert space H of physical states such that the ground state is invariant and field operators transform covariantly. Models show that one must allow for 'truncation' in the tensor product of representations of a quantum symmetry. This means that the dimension of the tensor product of two representations of dimension σ 1 and σ 2 may be strictly smaller than σ 1 σ 2 . Consistency of the transformation law of field operators local braid relations leads us to expect, that (weak) quasi quantum groups are the most general symmetries in local quantum theory. The elements of the R-matrix which appears in these local braid relations turn out to be operators on H in general. It will be explained in detail how examples of field algebras with weak quasi quantum group symmetry can be obtained. Given a set of observable field with a finite number of superselection sectors, a quantum symmetry together with a complete set of covariant field operators which obey local braid relations are constructed. A covariant transformation law for adjoint fields is not automatic but will follow when the existence of an appropriate antipode is assumed. At the example of the chiral critical Ising model, non-uniqueness of the quantum symmetry will be demonstrated. Generalized quantum symmetries yield examples of gauge symmetries in non-commutative geometry. Quasi-quantum planes are introduced as the simplest examples of quasi-associative differential geometry. (Weak) quasi quantum groups can act on them by generalized derivations much as quantum groups do in non-commutative (differential-) geometry
Jump resonant frequency islands in nonlinear feedback control systems
Koenigsberg, W. D.; Dunn, J. C.
1975-01-01
A new type of jump resonance is predicted and observed in certain nonlinear feedback control systems. The new jump resonance characteristic is described as a 'frequency island' due to the fact that a portion of the input-output transfer characteristic is disjoint from the main body. The presence of such frequency islands was predicted by using a sinusoidal describing function characterization of the dynamics of an inertial gyro employing nonlinear ternary rebalance logic. While the general conditions under which such islands are possible has not been examined, a numerical approach is presented which can aid in establishing their presence. The existence of the frequency islands predicted for the ternary rebalanced gyro was confirmed by simulating the nonlinear system and measuring the transfer function.
Age distribution dynamics with stochastic jumps in mortality.
Calabrese, Salvatore; Porporato, Amilcare; Laio, Francesco; D'Odorico, Paolo; Ridolfi, Luca
2017-11-01
While deterministic age distribution models have been extensively studied and applied in various disciplines, little work has been devoted to understanding the role of stochasticity in birth and mortality terms. In this paper, we analyse a stochastic M'Kendrick-von Foerster equation in which jumps in mortality represent intense losses of population due to external events. We present explicit solutions for the probability density functions of the age distribution and the total population and for the temporal dynamics of their moments. We also derive the dynamics of the mean age of the population and its harmonic mean. The framework is then used to calculate the age distribution of salt in the soil root zone, where the accumulation of salt by atmospheric deposition is counteracted by plant uptake and by jump losses due to percolation events.
Jumps and stochastic volatility in oil prices: Time series evidence
International Nuclear Information System (INIS)
Larsson, Karl; Nossman, Marcus
2011-01-01
In this paper we examine the empirical performance of affine jump diffusion models with stochastic volatility in a time series study of crude oil prices. We compare four different models and estimate them using the Markov Chain Monte Carlo method. The support for a stochastic volatility model including jumps in both prices and volatility is strong and the model clearly outperforms the others in terms of a superior fit to data. Our estimation method allows us to obtain a detailed study of oil prices during two periods of extreme market stress included in our sample; the Gulf war and the recent financial crisis. We also address the economic significance of model choice in two option pricing applications. The implied volatilities generated by the different estimated models are compared and we price a real option to develop an oil field. Our findings indicate that model choice can have a material effect on the option values.
Insider Models with Finite Utility in Markets with Jumps
International Nuclear Information System (INIS)
Kohatsu-Higa, Arturo; Yamazato, Makoto
2011-01-01
In this article we consider, under a Lévy process model for the stock price, the utility optimization problem for an insider agent whose additional information is the final price of the stock blurred with an additional independent noise which vanishes as the final time approaches. Our main interest is establishing conditions under which the utility of the insider is finite. Mathematically, the problem entails the study of a “progressive” enlargement of filtration with respect to random measures. We study the jump structure of the process which leads to the conclusion that in most cases the utility of the insider is finite and his optimal portfolio is bounded. This can be explained financially by the high risks involved in models with jumps.
Control and filtering for semi-Markovian jump systems
Li, Fanbiao; Wu, Ligang
2017-01-01
This book presents up-to-date research developments and novel methodologies on semi-Markovian jump systems (S-MJS). It presents solutions to a series of problems with new approaches for the control and filtering of S-MJS, including stability analysis, sliding mode control, dynamic output feedback control, robust filter design, and fault detection. A set of newly developed techniques such as piecewise analysis method, positively invariant set approach, event-triggered method, and cone complementary linearization approaches are presented. Control and Filtering for Semi-Markovian Jump Systems is a comprehensive reference for researcher and practitioners working in control engineering, system sciences and applied mathematics, and is also a useful source of information for senior undergraduates and graduates in these areas. The readers will benefit from some new concepts, new models and new methodologies with practical significance in control engineering and signal processing.
Option Pricing with Stochastic Volatility and Jump Diffusion Processes
Directory of Open Access Journals (Sweden)
Radu Lupu
2006-03-01
Full Text Available Option pricing by the use of Black Scholes Merton (BSM model is based on the assumption that asset prices have a lognormal distribution. In spite of the use of these models on a large scale, both by practioners and academics, the assumption of lognormality is rejected by the history of returns. The objective of this article is to present the methods that developed after the Black Scholes Merton environment and deals with the option pricing model adjustment to the empirical properties of asset returns. The main models that appeared after BSM allowed for special changes of the returns that materialized in jump-diffusion and stochastic volatility processes. The article presents the foundations of risk neutral options evaluation and the empirical evidence that fed the amendment of the lognormal assumption in the first part and shows the evaluation procedure under the assumption of stock prices following the jump-diffusion process and the stochastic volatility process.
VaR: Exchange Rate Risk and Jump Risk
Directory of Open Access Journals (Sweden)
Fen-Ying Chen
2010-01-01
Full Text Available Incorporating the Poisson jumps and exchange rate risk, this paper provides an analytical VaR to manage market risk of international portfolios over the subprime mortgage crisis. There are some properties in the model. First, different from past studies in portfolios valued only in one currency, this model considers portfolios not only with jumps but also with exchange rate risk, that is vital for investors in highly integrated global financial markets. Second, in general, the analytical VaR solution is more accurate than historical simulations in terms of backtesting and Christoffersen's independence test (1998 for small portfolios and large portfolios. In other words, the proposed model is reliable not only for a portfolio on specific stocks but also for a large portfolio. Third, the model can be regarded as the extension of that of Kupiec (1999 and Chen and Liao (2009.
Forecasting Exchange Rate Volatility in the Presence of Jumps
DEFF Research Database (Denmark)
Busch, Thomas; Christensen, Bent Jesper; Nielsen, Morten Ørregaard
We study measures of foreign exchange rate volatility based on high-frequency (5-minute) $/DM exchange rate returns using recent nonparametric statistical techniquesto compute realized return volatility and its separate continuous sample path and jumpcomponents, and measures based on prices...... of exchange rate futures options, allowingcalculation of option implied volatility. We find that implied volatility is an informationallyeﬃcient but biased forecast of future realized exchange rate volatility. Furthermore,we show that log-normality is an even better distributional approximation...... for impliedvolatility than for realized volatility in this market. Finally, we show that the jump componentof future realized exchange rate volatility is to some extent predictable, and thatoption implied volatility is the dominant forecast of the future jump component....
AGS Fast spin resonance jump, magnets and power supplies
International Nuclear Information System (INIS)
Glenn, J.W.; Huang, H.; Liaw, C. J.; Marneris, I.; Meng, W.; Mi, J. L.; Rosas, P.; Sandberg, J.; Tuozzolo, J.; Zhang, A.
2009-01-01
In order to cross more rapidly the 82 weak spin resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration of polarized protons. The current in the magnets creating this tune jump will rise in 100 (micro)s, hold flat for about 4 ms and fan to zero in 100 (micro)s. Laminated beam transport quadrupole magnets have been recycled by installing new two turn coils and longitudinal laminated pole tip shims that reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and operational experience are described
LOAD THAT MAXIMIZES POWER OUTPUT IN COUNTERMOVEMENT JUMP
Directory of Open Access Journals (Sweden)
Pedro Jimenez-Reyes
2016-02-01
Full Text Available ABSTRACT Introduction: One of the main problems faced by strength and conditioning coaches is the issue of how to objectively quantify and monitor the actual training load undertaken by athletes in order to maximize performance. It is well known that performance of explosive sports activities is largely determined by mechanical power. Objective: This study analysed the height at which maximal power output is generated and the corresponding load with which is achieved in a group of male-trained track and field athletes in the test of countermovement jump (CMJ with extra loads (CMJEL. Methods: Fifty national level male athletes in sprinting and jumping performed a CMJ test with increasing loads up to a height of 16 cm. The relative load that maximized the mechanical power output (Pmax was determined using a force platform and lineal encoder synchronization and estimating the power by peak power, average power and flight time in CMJ. Results: The load at which the power output no longer existed was at a height of 19.9 ± 2.35, referring to a 99.1 ± 1% of the maximum power output. The load that maximizes power output in all cases has been the load with which an athlete jump a height of approximately 20 cm. Conclusion: These results highlight the importance of considering the height achieved in CMJ with extra load instead of power because maximum power is always attained with the same height. We advise for the preferential use of the height achieved in CMJEL test, since it seems to be a valid indicative of an individual's actual neuromuscular potential providing a valid information for coaches and trainers when assessing the performance status of our athletes and to quantify and monitor training loads, measuring only the height of the jump in the exercise of CMJEL.
The Economics of Bitcoins - Market Characteristics and Price Jumps
Marc Gronwald
2014-01-01
This paper deals with the economics of Bitcoins in two ways. First, it broadens the discussion on how to capture Bitcoins using economic terms. Center stage in this analysis take the discussion of some unique characteristics of this market as well as the comparison of Bitcoins and gold. Second, the paper empirically analyses Bitcoin prices using an autoregressive jump-intensity GARCH model; a model tested and proven by the empirical finance community. Results suggest that Bitcoin price are pa...
Price jumps in Visegrad country stock markets: an empirical analysis
Czech Academy of Sciences Publication Activity Database
Novotný, Jan
-, č. 412 (2010), s. 1-33 ISSN 1211-3298 R&D Projects: GA ČR(CZ) GA402/08/1376; GA MŠk LC542 Grant - others:MŠk(CZ) SVV-2010-261801 Institutional research plan: CEZ:MSM0021620846 Keywords : financial markets * Visegrad region * price jumps Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp412.pdf
Numerical Analysis for Stochastic Partial Differential Delay Equations with Jumps
Li, Yan; Hu, Junhao
2013-01-01
We investigate the convergence rate of Euler-Maruyama method for a class of stochastic partial differential delay equations driven by both Brownian motion and Poisson point processes. We discretize in space by a Galerkin method and in time by using a stochastic exponential integrator. We generalize some results of Bao et al. (2011) and Jacob et al. (2009) in finite dimensions to a class of stochastic partial differential delay equations with jumps in infinite dimensions.
Incomplete Financial Markets and Jumps in Asset Prices
DEFF Research Database (Denmark)
Crès, Hervé; Markeprand, Tobias Ejnar; Tvede, Mich
A dynamic pure-exchange general equilibrium model with uncertainty is studied. Fundamentals are supposed to depend continuously on states of nature. It is shown that: 1. if financial markets are complete, then asset prices vary continuously with states of nature, and; 2. if financial markets...... are incomplete, jumps in asset prices may be unavoidable. Consequently incomplete financial markets may increase volatility in asset prices significantly....
CONNECTION OF FUNCTIONAL ABILITIES WITH JUMPING AND THROWING ATHLETIC DISCIPLINES
Igor Stanojević; Dejan Milenković
2014-01-01
The aim of this study was to determine the connection between functional abilities with results of jumping and throwing athletic disciplines with athletes. The sample was taken from a population of elementary school students from Prokuplje region, 13 and 14 old, included in regular physical education classes. The sample consisted of 200 male athletes involved in the training process in sports clubs at least three times a week in addition to physical education classes. For assessment of functi...
Abdominal muscle activity during a standing long jump.
Okubo, Yu; Kaneoka, Koji; Shiina, Itsuo; Tatsumura, Masaki; Miyakawa, Shumpei
2013-08-01
Experimental laboratory study. To measure the activation patterns (onset and magnitude) of the abdominal muscles during a standing long jump using wire and surface electromyography. Activation patterns of the abdominal muscles, especially the deep muscles such as the transversus abdominis (TrA), have yet to be examined during full-body movements such as jumping. Thirteen healthy men participated. Wire electrodes were inserted into the TrA with the guidance of ultrasonography, and surface electrodes were attached to the skin overlying the rectus abdominis (RA) and external oblique (EO). Electromyographic signals and video images were recorded while each subject performed a standing long jump. The jump task was divided into 3 phases: preparation, push-off, and float. For each muscle, activation onset relative to the onset of the RA and normalized muscle activation levels (percent maximum voluntary contraction) were analyzed during each phase. Comparisons between muscles and phases were assessed using 2-way analyses of variance. The onset times of the TrA and EO relative to the onset of the RA were -0.13 ? 0.17 seconds and -0.02 ? 0.07 seconds, respectively. Onset of TrA activation was earlier than that of the EO. The activation levels of all 3 muscles were significantly greater during the push-off phase than during the preparation and float phases. Consistent with previously published trunk-perturbation studies in healthy persons, the TrA was activated prior to the RA and EO. Additionally, the highest muscle activation levels were observed during the push-off phase.
Do co-jumps impact correlations in currency markets?
Czech Academy of Sciences Publication Activity Database
Baruník, J.; Vácha, Lukáš
Roč. 37, č. 1 ( 2018 ), s. 97-119 ISSN 1386-4181 Grant - others:GA ČR GA16-14151S Institutional support: RVO:67985556 Keywords : Co-jumps * Currency markets * Realized covariance * Wavelets * Bootstrap Subject RIV: AH - Economics OBOR OECD: Finance Impact factor: 1.134, year: 2016 http://library.utia.cas.cz/separaty/ 2018 /E/vacha-0487659.pdf
INARCH(1) processes: Higher-order moments and jumps
Weiß , Christian H.
2010-01-01
Abstract The INARCH(1) model is a simple but practically relevant, two-parameter model for processes of overdispersed counts with an autoregressive serial dependence structure. We derive closed-form expressions for the joint (central) moments and cumulants of the INARCH(1) model up to order 4. These expressions are applied to derive moments of jumps in INARCH(1) processes. We illustrate this kind of application with a real-data example, and outline further potential applications. ...
Ski jumping takeoff in a wind tunnel with skis.
Virmavirta, Mikko; Kivekäs, Juha; Komi, Paavo
2011-11-01
The effect of skis on the force-time characteristics of the simulated ski jumping takeoff was examined in a wind tunnel. Takeoff forces were recorded with a force plate installed under the tunnel floor. Signals from the front and rear parts of the force plate were collected separately to examine the anteroposterior balance of the jumpers during the takeoff. Two ski jumpers performed simulated takeoffs, first without skis in nonwind conditions and in various wind conditions. Thereafter, the same experiments were repeated with skis. The jumpers were able to perform very natural takeoff actions (similar to the actual takeoff) with skis in wind tunnel. According to the subjective feeling of the jumpers, the simulated ski jumping takeoff with skis was even easier to perform than the earlier trials without skis. Skis did not much influence the force levels produced during the takeoff but they still changed the force distribution under the feet. Contribution of the forces produced under the rear part of the feet was emphasized probably because the strong dorsiflexion is needed for lifting the skis to the proper flight position. The results presented in this experiment emphasize that research on ski jumping takeoff can be advanced by using wind tunnels.
Aerodynamics of ski jumping flight and its control: II. Simulations
Lee, Jungil; Lee, Hansol; Kim, Woojin; Choi, Haecheon
2015-11-01
In a ski jumping competition, it is essential to analyze the effect of various posture parameters of a ski jumper to achieve a longer flight distance. For this purpose, we conduct a large eddy simulation (LES) of turbulent flow past a model ski jumper which is obtained by 3D scanning a ski jumper's body (Mr. Chil-Ku Kang, member of the Korean national team). The angle of attack of the jump ski is 30° and the Reynolds number based on the length of the jump ski is 540,000. The flow statistics including the drag and lift coefficients in flight are in good agreements with our own experimental data. We investigate the flow characteristics such as the flow separation and three-dimensional vortical structures and their effects on the drag and lift. In addition to LES, we construct a simple geometric model of a ski jumper where each part of the ski jumper is modeled as a canonical bluff body such as the sphere, cylinder and flat plate, to find its optimal posture. The results from this approach will be compared with those by LES and discussed. Supported by NRF program (2014M3C1B1033848, 2014R1A1A1002671).
Kinematic Chains in Ski Jumping In-run Posture.
Janurová, Eva; Janura, Miroslav; Cabell, Lee; Svoboda, Zdeněk; Vařeka, Ivan; Elfmark, Milan
2013-12-18
The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper's body's kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper's body at the in-run position are greater nearer the chain's ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments' positions in the kinematic chain of the ski jumper's body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.
JUMP LANDING CHARACTERISTICS IN ELITE SOCCER PLAYERS WITH CEREBRAL PALSY
Directory of Open Access Journals (Sweden)
Jesús Cámara
2013-04-01
Full Text Available The aim of the present study was to analyse the parameters that characterize the vertical ground reaction force during the landing phase of a jump, and to determine the relationship among these parameters in elite soccer players with cerebral palsy (CP. Thirteen male members of the Spanish national soccer team for people with CP (mean age: 27.1 ± 4.7 years volunteered for the study. Each participant performed three counter movement jumps. The characteristics of the first peak of the vertical ground reaction force during the landing phase of a jump, which corresponds to the forefoot contact with the ground, were similar to the results obtained in previous studies. However, a higher magnitude of rearfoot contact with the ground (F2 was observed in participants with CP than in participants without CP. Furthermore, a significant correlation between F2 magnitude and the elapsed time until its production (T2 was not observed (r = -0.474 for p = 0.102. This result implies that a landing technique based on a delay in the production of F2 might not be effective to reduce its magnitude, contrary to what has been observed in participants without CP. The absence of a significant correlation between these two parameters in the present study, and the high magnitude of F2, suggest that elite soccer players with CP should use footwear with proper cushioning characteristics.
Jump dynamics with structural breaks for crude oil prices
International Nuclear Information System (INIS)
Lee, Yen-Hsien; Hu, Hsu-Ning; Chiou, Jer-Shiou
2010-01-01
This study investigates the joint phenomena of permanent and transitory components in conditional variance and jump intensity along with verification of structural breaks for crude oil prices. We adopt a Component-ARJI model with structural break analysis, utilizing daily data on West Texas Intermediate crude oil spot and futures contracts. The analytical results verify the existence of permanent and transitory components in conditional variance, with the permanent component of conditional variance increasing with the occurrence of a sudden major event (such as the Iraqi Invasion of Kuwait, Operation Desert Storm and the war between the US and Iraq), and a relatively greater increase in the transitory component over the same period. Notably, jump intensity fluctuates with an increase in the transitory component of conditional variance in response to abnormal events. It is the transitory component which serves as the primary influential factor for jumps in returns; therefore, speculators are willing to take large risks, particularly with respect to anticipating future price movements, or gambling, in the hopes of rapidly making substantial gains; thus, speculators prefer the temporary volatility component and engage in trade activities. However, investors prefer the permanent volatility component, because they may well be better off relocating their assets into more stable portfolios to outperform the market portfolio over the long run. (author)
NONINVASIVE DETERMINATION OF KNEE CARTILAGE DEFORMATION DURING JUMPING
Directory of Open Access Journals (Sweden)
Djordje Kosanic
2009-12-01
Full Text Available The purpose of this investigation was to use a combination of image processing, force measurements and finite element modeling to calculate deformation of the knee cartilage during jumping. Professional athletes performed jumps analyzed using a force plate and high-speed video camera system. Image processing was performed on each frame of video using a color recognition algorithm. A simplified mass-spring-damper model was utilized for determination of global force and moment on the knee. Custom software for fitting the coupling characteristics was created. Simulated results were used as input data for the finite element calculation of cartilage deformation in the athlete's knee. Computer simulation data was compared with the average experimental ground reaction forces. The results show the three-dimensional mechanical deformation distribution inside the cartilage volume. A combination of the image recognition technology, force plate measurements and the finite element cartilage deformation in the knee may be used in the future as an effective noninvasive tool for prediction of injury during jumping
Might as well jump: sound affects muscle activation in skateboarding.
Directory of Open Access Journals (Sweden)
Paola Cesari
Full Text Available The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age--some of them without any skills in skateboarding and others experts in this sport--were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements.
Might as well jump: sound affects muscle activation in skateboarding.
Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico
2014-01-01
The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age--some of them without any skills in skateboarding and others experts in this sport--were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements.
Jump dynamics with structural breaks for crude oil prices
Energy Technology Data Exchange (ETDEWEB)
Lee, Yen-Hsien [Department of Finance, Chung Yuan Christian University (China); Hu, Hsu-Ning [Department of Money, Banking and Finance, TamKang University (China); Chiou, Jer-Shiou [Department of Finance and Banking, Shih Chien University, 70 Ta-Chih Street, Taipei 104 (China)
2010-03-15
This study investigates the joint phenomena of permanent and transitory components in conditional variance and jump intensity along with verification of structural breaks for crude oil prices. We adopt a Component-ARJI model with structural break analysis, utilizing daily data on West Texas Intermediate crude oil spot and futures contracts. The analytical results verify the existence of permanent and transitory components in conditional variance, with the permanent component of conditional variance increasing with the occurrence of a sudden major event (such as the Iraqi Invasion of Kuwait, Operation Desert Storm and the war between the US and Iraq), and a relatively greater increase in the transitory component over the same period. Notably, jump intensity fluctuates with an increase in the transitory component of conditional variance in response to abnormal events. It is the transitory component which serves as the primary influential factor for jumps in returns; therefore, speculators are willing to take large risks, particularly with respect to anticipating future price movements, or gambling, in the hopes of rapidly making substantial gains; thus, speculators prefer the temporary volatility component and engage in trade activities. However, investors prefer the permanent volatility component, because they may well be better off relocating their assets into more stable portfolios to outperform the market portfolio over the long run. (author)
Fundamental tests in Cavity Quantum Electrodynamics
CERN. Geneva
2010-01-01
At the dawn of quantum physics, Einstein and Bohr had the dream to confine a photon in a box and to use this contraption in order to illustrate the strange laws of the quantum world. Cavity Quantum Electrodynamics has now made this dream real, allowing us to actually achieve in the laboratory variants of the thought experiments of the founding fathers of quantum theory. In our work at Ecole Normale Supérieure, we use a beam of Rydberg atoms to manipulate and probe non-destructively microwave photons trapped in a very high Q superconducting cavity. We realize ideal quantum non-demolition (QND) measurements of photon numbers, observe the radiation quantum jumps due to cavity relaxation and prepare non-classical fields such as Fock and Schrödinger cat states. Combining QND photon counting with a homodyne mixing method, we reconstruct the Wigner functions of these non-classical states and, by taking snapshots of these functions at increasing times, obtain movies of the decoherence process. These experiments ope...
Quantum games as quantum types
Delbecque, Yannick
In this thesis, we present a new model for higher-order quantum programming languages. The proposed model is an adaptation of the probabilistic game semantics developed by Danos and Harmer [DH02]: we expand it with quantum strategies which enable one to represent quantum states and quantum operations. Some of the basic properties of these strategies are established and then used to construct denotational semantics for three quantum programming languages. The first of these languages is a formalisation of the measurement calculus proposed by Danos et al. [DKP07]. The other two are new: they are higher-order quantum programming languages. Previous attempts to define a denotational semantics for higher-order quantum programming languages have failed. We identify some of the key reasons for this and base the design of our higher-order languages on these observations. The game semantics proposed in this thesis is the first denotational semantics for a lambda-calculus equipped with quantum types and with extra operations which allow one to program quantum algorithms. The results presented validate the two different approaches used in the design of these two new higher-order languages: a first one where quantum states are used through references and a second one where they are introduced as constants in the language. The quantum strategies presented in this thesis allow one to understand the constraints that must be imposed on quantum type systems with higher-order types. The most significant constraint is the fact that abstraction over part of the tensor product of many unknown quantum states must not be allowed. Quantum strategies are a new mathematical model which describes the interaction between classical and quantum data using system-environment dialogues. The interactions between the different parts of a quantum system are described using the rich structure generated by composition of strategies. This approach has enough generality to be put in relation with other
International Nuclear Information System (INIS)
Kaçal, Mustafa Recep; Han, İbrahim; Akman, Ferdi
2015-01-01
Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature. - Highlights: • This work regard the K shell absorption jump ratios and jump factors of Ti, Cr, Fe, Co, Ni and Cu. • This paper presents the first measurement of these parameters using the experimental K shell fluorescence parameters. • A good agreement was found between experimental and theoretical values. • The EDXRF technique was suitable, precise and reliable for the measurement of these atomic parameters
Can, Ibrahim
2018-01-01
The purpose of this study was to investigate the relationship between sprint and jump performance with velocity parameters in the loaded-squat jump exercise (SQ[subscript Loaded]). In accordance with this purpose, a total of 13 athletes competing in martial sports have participated in this study voluntarily. In this study, sprint tests, vertical…
Take-off analysis of the Olympic ski jumping competition (HS-106m).
Virmavirta, Mikko; Isolehto, Juha; Komi, Paavo; Schwameder, Hermann; Pigozzi, Fabio; Massazza, Giuseppe
2009-05-29
The take-off phase (approximately 6m) of the jumps of all athletes participating in the individual HS-106m hill ski jumping competition at the Torino Olympics was filmed with two high-speed cameras. The high altitude of the Pragelato ski jumping venue (1600m) and slight tail wind in the final jumping round were expected to affect the results of this competition. The most significant correlation with the length of the jump was found in the in-run velocity (r=0.628, pski jumping, and suggests that good jumpers simply had smaller friction between their skis and the in-run tracks and/or the aerodynamic quality of their in-run position was better. Angular velocity of the hip joint of the best jumpers was also correlated with jumping distance (r=0.651, pjumped approximately the same distance. This certainly improves the interests in ski jumping among athletes and spectators. The comparison between the take-off techniques of the best jumpers showed that even though the more marked upper body movement creates higher air resistance, it does not necessarily result in shorter jumping distance if the exposure time to high air resistance is not too long. A comparison between the first and second round jumps of the same jumpers showed that the final results in this competition were at least partly affected by the wind conditions.
Lower Extremity Kinematics Differed Between a Controlled Drop-Jump and Volleyball-Takeoffs.
Beardt, Bradley S; McCollum, Myranda R; Hinshaw, Taylour J; Layer, Jacob S; Wilson, Margaret A; Zhu, Qin; Dai, Boyi
2018-04-03
Previous studies utilizing jump-landing biomechanics to predict anterior cruciate ligament injuries have shown inconsistent findings. The purpose of this study was to quantify the differences and correlations in jump-landing kinematics between a drop-jump, a controlled volleyball-takeoff, and a simulated-game volleyball-takeoff. Seventeen female volleyball players performed these three tasks on a volleyball court while three-dimensional kinematic data were collected by three calibrated camcorders. Participants demonstrated significantly increased jump height, shorter stance time, increased time differences in initial contact between two feet, increased knee and hip flexion at initial contact and decreased peak knee and hip flexion for both left and right legs, and decreased knee-ankle distance ratio at the lowest height of mid-hip for the two volleyball-takeoffs compared with the drop-jump (p jump and two volleyball-takeoffs. Controlled drop-jump kinematics may not represent jump-landing kinematics exhibited during volleyball competition. Jump-landing mechanics during sports-specific tasks may better represent those exhibited during sports competition and their associated risk of ACL injury compared with the drop-jump.
Research on one Bio-inspired Jumping Locomotion Robot for Search and Rescue
Directory of Open Access Journals (Sweden)
Dunwen Wei
2014-10-01
Full Text Available Jumping locomotion is much more effective than other locomotion means in order to tackle the unstructured and complex environment in research and rescue. Here, a bio-inspired jumping robot with a closed-chain mechanism is proposed to achieve the power amplification during taking-off. Through actuating one variable transmission mechanism to change the transmission ratio, the jumping robot reveals biological characteristics in the phase of posture adjustment when adjusting the height and distance of one jump. The kinematics and dynamics of the simplified jumping mechanism model in one jumping cycle sequence are analysed. A compliant contact model considering nonlinear damping is investigated for jumping performance under different terrain characteristics. The numerical simulation algorithm with regard to solving the dynamical equation is described and simulation results are discussed. Finally, one primary prototype and experiment are described. The experimental results show the distance of jumping in the horizontal direction increases with the increasing gear ratio, while the height of jumping decreases in reverse. The jumping robot can enhance the capability to adapt to unknown cluttered environments, such as those encountered in research and rescue, using this strategy.
Intra-Personal and Inter-Personal Kinetic Synergies During Jumping
Directory of Open Access Journals (Sweden)
Slomka Kajetan
2015-12-01
Full Text Available We explored synergies between two legs and two subjects during preparation for a long jump into a target. Synergies were expected during one-person jumping. No such synergies were expected between two persons jumping in parallel without additional contact, while synergies were expected to emerge with haptic contact and become stronger with strong mechanical contact. Subjects performed jumps either alone (each foot standing on a separate force platform or in dyads (parallel to each other, each person standing on a separate force platform without any contact, with haptic contact, and with strong coupling. Strong negative correlations between pairs of force variables (strong synergies were seen in the vertical force in one-person jumps and weaker synergies in two-person jumps with the strong contact. For other force variables, only weak synergies were present in one-person jumps and no negative correlations between pairs of force variable for two-person jumps. Pairs of moment variables from the two force platforms at steady state showed positive correlations, which were strong in one-person jumps and weaker, but still significant, in two-person jumps with the haptic and strong contact. Anticipatory synergy adjustments prior to action initiation were observed in oneperson trials only. We interpret the different results for the force and moment variables at steady state as reflections of postural sway.
Salticid predation as one potential driving force of ant mimicry in jumping spiders
Huang, Jin-Nan; Cheng, Ren-Chung; Li, Daiqin; Tso, I-Min
2011-01-01
Many spiders possess myrmecomorphy, and species of the jumping spider genus Myrmarachne exhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods. PMID:20961898
Numerical study of laminar, standing hydraulic jumps in a planar geometry.
Dasgupta, Ratul; Tomar, Gaurav; Govindarajan, Rama
2015-05-01
We solve the two-dimensional, planar Navier-Stokes equations to simulate a laminar, standing hydraulic jump using a Volume-of-Fluid method. The geometry downstream of the jump has been designed to be similar to experimental conditions by including a pit at the edge of the platform over which liquid film flows. We obtain jumps with and without separation. Increasing the inlet Froude number pushes the jump downstream and makes the slope of the jump weaker, consistent with experimental observations of circular jumps, and decreasing the Reynolds number brings the jump upstream while making it steeper. We study the effect of the length of the domain and that of a downstream obstacle on the structure and location of the jump. The transient flow which leads to a final steady jump is described for the first time to our knowledge. In the moderate Reynolds number regime, we obtain steady undular jumps with a separated bubble underneath the first few undulations. Interestingly, surface tension leads to shortening of wavelength of these undulations. We show that the undulations can be explained using the inviscid theory of Benjamin and Lighthill (Proc. R. Soc. London, Ser. A, 1954). We hope this new finding will motivate experimental verification.
Busch, Paul; Pellonpää, Juha-Pekka; Ylinen, Kari
2016-01-01
This is a book about the Hilbert space formulation of quantum mechanics and its measurement theory. It contains a synopsis of what became of the Mathematical Foundations of Quantum Mechanics since von Neumann’s classic treatise with this title. Fundamental non-classical features of quantum mechanics—indeterminacy and incompatibility of observables, unavoidable measurement disturbance, entanglement, nonlocality—are explicated and analysed using the tools of operational quantum theory. The book is divided into four parts: 1. Mathematics provides a systematic exposition of the Hilbert space and operator theoretic tools and relevant measure and integration theory leading to the Naimark and Stinespring dilation theorems; 2. Elements develops the basic concepts of quantum mechanics and measurement theory with a focus on the notion of approximate joint measurability; 3. Realisations offers in-depth studies of the fundamental observables of quantum mechanics and some of their measurement implementations; and 4....
Walls, D F
2007-01-01
Quantum Optics gives a comprehensive coverage of developments in quantum optics over the past years. In the early chapters the formalism of quantum optics is elucidated and the main techniques are introduced. These are applied in the later chapters to problems such as squeezed states of light, resonance fluorescence, laser theory, quantum theory of four-wave mixing, quantum non-demolition measurements, Bell's inequalities, and atom optics. Experimental results are used to illustrate the theory throughout. This yields the most comprehensive and up-to-date coverage of experiment and theory in quantum optics in any textbook. More than 40 exercises helps readers test their understanding and provide practice in quantitative problem solving.
International Nuclear Information System (INIS)
Markov, M.A.; West, P.C.
1984-01-01
This book discusses the state of the art of quantum gravity, quantum effects in cosmology, quantum black-hole physics, recent developments in supergravity, and quantum gauge theories. Topics considered include the problems of general relativity, pregeometry, complete cosmological theories, quantum fluctuations in cosmology and galaxy formation, a new inflationary universe scenario, grand unified phase transitions and the early Universe, the generalized second law of thermodynamics, vacuum polarization near black holes, the relativity of vacuum, black hole evaporations and their cosmological consequences, currents in supersymmetric theories, the Kaluza-Klein theories, gauge algebra and quantization, and twistor theory. This volume constitutes the proceedings of the Second Seminar on Quantum Gravity held in Moscow in 1981
Approaches to open quantum systems: Decoherence, localisation and all that
International Nuclear Information System (INIS)
Yu Ting
1998-01-01
This thesis is mainly concerned with issues in quantum open systems and the foundations of quantum theory. Chapter I introduces the aim, background and main results which take place in the following chapters. Chapters II and III are used to study and compare the decoherent histories approach, the environment-induced decoherence and the localisation properties of the solutions to the stochastic Schrodinger equation in quantum jump simulation and quantum state diffusion approaches, for a quantum two-level system model. We show, in particular, that there is a close connection between the decoherent histories and the quantum jump simulation, complementing a connection with the quantum state diffusion approach noted earlier by Diosi, Gisin, Halliwell and Percival. In the case of the decoherent histories analysis, the degree of approximate decoherence is discussed in detail. As by-product, by using the von Neumann entropy, we also discuss the predictability and its relation to the upper bounds of degree of decoherence. In Chapter IV, we give an alternative and elementary derivation of the Hu-Paz-Ghang master equation for quantum Brownian motion in a general environment, which involves tracing the evolution equation for the Wigner function. We also discuss the master equation in some special cases. This master equation provides a very useful tool to study the decoherence of a quantum system due to the interaction with its environment. In Chapter V, a derivation of the parameter-based uncertainty relation between position and momentum is given. This uncertainty relation can be regarded as an exact counterpart of the time-energy uncertainty relation. The final chapter is a rather brief summary of the thesis. (author)
Stapp, Henry P.
2011-01-01
Robert Griffiths has recently addressed, within the framework of a 'consistent quantum theory' that he has developed, the issue of whether, as is often claimed, quantum mechanics entails a need for faster-than-light transfers of information over long distances. He argues that the putative proofs of this property that involve hidden variables include in their premises some essentially classical-physics-type assumptions that are fundamentally incompatible with the precepts of quantum physics. O...
Grifoni, Milena
1997-01-01
In this thesis, ratchet systems operating in the quantum regime are investigated. Ratchet systems, also known as Brownian motors, are periodic systems presenting an intrinsic asymmetry which can be exploited to extract work out of unbiased forces. As a model for ratchet systems, we consider the motion of a particle in a one-dimensional periodic and asymmetric potential, interacting with a thermal environment, and subject to an unbiased driving force. In quantum ratchets, intrinsic quantum flu...
Quantum space and quantum completeness
Jurić, Tajron
2018-05-01
Motivated by the question whether quantum gravity can "smear out" the classical singularity we analyze a certain quantum space and its quantum-mechanical completeness. Classical singularity is understood as a geodesic incompleteness, while quantum completeness requires a unique unitary time evolution for test fields propagating on an underlying background. Here the crucial point is that quantum completeness renders the Hamiltonian (or spatial part of the wave operator) to be essentially self-adjoint in order to generate a unique time evolution. We examine a model of quantum space which consists of a noncommutative BTZ black hole probed by a test scalar field. We show that the quantum gravity (noncommutative) effect is to enlarge the domain of BTZ parameters for which the relevant wave operator is essentially self-adjoint. This means that the corresponding quantum space is quantum complete for a larger range of BTZ parameters rendering the conclusion that in the quantum space one observes the effect of "smearing out" the singularity.
International Nuclear Information System (INIS)
Francis Maria Anand, L.; Gudennavar, S.B.; Bubbly, S.G.; Joseph, Daisy
2013-01-01
The article presents a simple method of measuring K-shell absorption jump ratios and jump factors for elements in the field of X-ray spectroscopy. The K-shell jump ratios and jump factors for Molybdenum and Silver are measured by adopting 2ŏ-geometrical configuration and a weak gamma source. The characteristic K X-ray photons are excited in the targets using 32.8 keV barium X-ray photons from a weak 137 Cs radioactive source that is produced due to the internal conversion of cesium nucleus (IC). The fluorescent K X-ray photons are detected using low energy Si(Li) detector coupled to a 8k multichannel analyser. The K X-ray intensity ratios from X-ray fluorescent spectrum are measured experimentally, the total atomic attenuation cross section and the total atomic scattering cross sections are calculated using WinXcom software. The K-shell jump factor and jump ratio are computed using the measured K X-ray intensity ratios and the calculated K a , X-ray production cross section. The computed values of K-shell jump factor and jump ratio for molybdenum and silver are compared with the theoretical values and others' experimental data and are presented. The amount of uncertainty in the experimental measurement of K X-ray intensity ratios is less than 5%. Thus the 2ŏ-geometrical configuration method with weak gamma source can be an alternative simple method to measure the jump factors and the jump ratios of pure elements in the field of X-ray spectroscopy. (author)
International Nuclear Information System (INIS)
Basdevant, J.L.; Dalibard, J.; Joffre, M.
2008-01-01
All physics is quantum from elementary particles to stars and to the big-bang via semi-conductors and chemistry. This theory is very subtle and we are not able to explain it without the help of mathematic tools. This book presents the principles of quantum mechanics and describes its mathematical formalism (wave function, Schroedinger equation, quantum operators, spin, Hamiltonians, collisions,..). We find numerous applications in the fields of new technologies (maser, quantum computer, cryptography,..) and in astrophysics. A series of about 90 exercises with their answers is included. This book is based on a physics course at a graduate level. (A.C.)
International Nuclear Information System (INIS)
Rodgers, P.
1998-01-01
There is more to information than a string of ones and zeroes the ability of ''quantum bits'' to be in two states at the same time could revolutionize information technology. In the mid-1930s two influential but seemingly unrelated papers were published. In 1935 Einstein, Podolsky and Rosen proposed the famous EPR paradox that has come to symbolize the mysteries of quantum mechanics. Two years later, Alan Turing introduced the universal Turing machine in an enigmatically titled paper, On computable numbers, and laid the foundations of the computer industry one of the biggest industries in the world today. Although quantum physics is essential to understand the operation of transistors and other solid-state devices in computers, computation itself has remained a resolutely classical process. Indeed it seems only natural that computation and quantum theory should be kept as far apart as possible surely the uncertainty associated with quantum theory is anathema to the reliability expected from computers? Wrong. In 1985 David Deutsch introduced the universal quantum computer and showed that quantum theory can actually allow computers to do more rather than less. The ability of particles to be in a superposition of more than one quantum state naturally introduces a form of parallelism that can, in principle, perform some traditional computing tasks faster than is possible with classical computers. Moreover, quantum computers are capable of other tasks that are not conceivable with their classical counterparts. Similar breakthroughs in cryptography and communication followed. (author)
Energy Technology Data Exchange (ETDEWEB)
Rodgers, P
1998-03-01
There is more to information than a string of ones and zeroes the ability of ''quantum bits'' to be in two states at the same time could revolutionize information technology. In the mid-1930s two influential but seemingly unrelated papers were published. In 1935 Einstein, Podolsky and Rosen proposed the famous EPR paradox that has come to symbolize the mysteries of quantum mechanics. Two years later, Alan Turing introduced the universal Turing machine in an enigmatically titled paper, On computable numbers, and laid the foundations of the computer industry one of the biggest industries in the world today. Although quantum physics is essential to understand the operation of transistors and other solid-state devices in computers, computation itself has remained a resolutely classical process. Indeed it seems only natural that computation and quantum theory should be kept as far apart as possible surely the uncertainty associated with quantum theory is anathema to the reliability expected from computers? Wrong. In 1985 David Deutsch introduced the universal quantum computer and showed that quantum theory can actually allow computers to do more rather than less. The ability of particles to be in a superposition of more than one quantum state naturally introduces a form of parallelism that can, in principle, perform some traditional computing tasks faster than is possible with classical computers. Moreover, quantum computers are capable of other tasks that are not conceivable with their classical counterparts. Similar breakthroughs in cryptography and communication followed. (author)
International Nuclear Information System (INIS)
Khrennikov, Andrei; Klein, Moshe; Mor, Tal
2010-01-01
In number theory, a partition of a positive integer n is a way of writing n as a sum of positive integers. The number of partitions of n is given by the partition function p(n). Inspired by quantum information processing, we extend the concept of partitions in number theory as follows: for an integer n, we treat each partition as a basis state of a quantum system representing that number n, so that the Hilbert-space that corresponds to that integer n is of dimension p(n); the 'classical integer' n can thus be generalized into a (pure) quantum state ||ψ(n) > which is a superposition of the partitions of n, in the same way that a quantum bit (qubit) is a generalization of a classical bit. More generally, ρ(n) is a density matrix in that same Hilbert-space (a probability distribution over pure states). Inspired by the notion of quantum numbers in quantum theory (such as in Bohr's model of the atom), we then try to go beyond the partitions, by defining (via recursion) the notion of 'sub-partitions' in number theory. Combining the two notions mentioned above, sub-partitions and quantum integers, we finally provide an alternative definition of the quantum integers [the pure-state |ψ'(n)> and the mixed-state ρ'(n),] this time using the sub-partitions as the basis states instead of the partitions, for describing the quantum number that corresponds to the integer n.
International Nuclear Information System (INIS)
Deutsch, D.
1992-01-01
As computers become ever more complex, they inevitably become smaller. This leads to a need for components which are fabricated and operate on increasingly smaller size scales. Quantum theory is already taken into account in microelectronics design. This article explores how quantum theory will need to be incorporated into computers in future in order to give them their components functionality. Computation tasks which depend on quantum effects will become possible. Physicists may have to reconsider their perspective on computation in the light of understanding developed in connection with universal quantum computers. (UK)
Energy Technology Data Exchange (ETDEWEB)
Rodgers, P
1998-03-01
There is more to information than a string of ones and zeroes the ability of ''quantum bits'' to be in two states at the same time could revolutionize information technology. In the mid-1930s two influential but seemingly unrelated papers were published. In 1935 Einstein, Podolsky and Rosen proposed the famous EPR paradox that has come to symbolize the mysteries of quantum mechanics. Two years later, Alan Turing introduced the universal Turing machine in an enigmatically titled paper, On computable numbers, and laid the foundations of the computer industry one of the biggest industries in the world today. Although quantum physics is essential to understand the operation of transistors and other solid-state devices in computers, computation itself has remained a resolutely classical process. Indeed it seems only natural that computation and quantum theory should be kept as far apart as possible surely the uncertainty associated with quantum theory is anathema to the reliability expected from computers? Wrong. In 1985 David Deutsch introduced the universal quantum computer and showed that quantum theory can actually allow computers to do more rather than less. The ability of particles to be in a superposition of more than one quantum state naturally introduces a form of parallelism that can, in principle, perform some traditional computing tasks faster than is possible with classical computers. Moreover, quantum computers are capable of other tasks that are not conceivable with their classical counterparts. Similar breakthroughs in cryptography and communication followed. (author)
Tartakovskii, Alexander
2012-07-01
Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by
Directory of Open Access Journals (Sweden)
Vanderka Marián, Longová Katarína, Olasz Dávid, Krčmár Matúš, Walker Simon
2016-09-01
Full Text Available The purpose of the study was to determine the effects of 8 weeks of jump squat training on isometric half squat maximal force production (Fmax and rate of force development over 100ms (RFD100, countermovement jump (CMJ and squat jump (SJ height, and 50 m sprint time in moderately trained men. Sixty eight subjects (~21 years, ~180 cm, ~75 kg were divided into experimental (EXP; n = 36 and control (CON, n = 32 groups. Tests were completed pre-, mid- and post-training. EXP performed jump squat training 3 times per week using loads that allowed all repetitions to be performed with ≥90% of maximum average power output (13 sessions with 4 sets of 8 repetitions and 13 sessions with 8 sets of 4 repetitions. Subjects were given real-time feedback for every repetition during the training sessions. Significant improvements in Fmax from pre- to mid- (Δ ~14%, p<0.001, and from mid- to post-training (Δ ~4%, p < 0.001 in EXP were observed. In CON significantly enhanced Fmax from pre- to mid-training (Δ ~3.5%, p < 0.05 was recorded, but no other significant changes were observed in any other test. In RFD100 significant improvements from pre- to mid-training (Δ ~27%, p < 0.001, as well as from mid- to post-training (Δ ~17%, p < 0.01 were observed. CMJ and SJ height were significantly enhanced from pre- to mid-training (Δ ~10%, ~15%, respectively, p < 0.001 but no further changes occurred from mid- to post-training. Significant improvements in 50 m sprint time from pre- to mid-training (Δ -1%, p < 0.05, and from mid- to post-training (Δ -1.9%, p < 0.001 in EXP were observed. Furthermore, percent changes in EXP were greater than changes in CON during training. It appears that using jump squats with loads that allow repetitions to be performed ≥90% of maximum average power output can simultaneously improve several different athletic performance tasks in the short-term.
Quantum trajectories for time-dependent adiabatic master equations
Yip, Ka Wa; Albash, Tameem; Lidar, Daniel A.
2018-02-01
We describe a quantum trajectories technique for the unraveling of the quantum adiabatic master equation in Lindblad form. By evolving a complex state vector of dimension N instead of a complex density matrix of dimension N2, simulations of larger system sizes become feasible. The cost of running many trajectories, which is required to recover the master equation evolution, can be minimized by running the trajectories in parallel, making this method suitable for high performance computing clusters. In general, the trajectories method can provide up to a factor N advantage over directly solving the master equation. In special cases where only the expectation values of certain observables are desired, an advantage of up to a factor N2 is possible. We test the method by demonstrating agreement with direct solution of the quantum adiabatic master equation for 8-qubit quantum annealing examples. We also apply the quantum trajectories method to a 16-qubit example originally introduced to demonstrate the role of tunneling in quantum annealing, which is significantly more time consuming to solve directly using the master equation. The quantum trajectories method provides insight into individual quantum jump trajectories and their statistics, thus shedding light on open system quantum adiabatic evolution beyond the master equation.
Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump.
Yun, Sung Joon; Kim, Moon-Hwan; Weon, Jong-Hyuck; Kim, Young; Jung, Sung-Hoon; Kwon, Oh-Yun
2016-08-01
[Purpose] This study assessed the relationships between peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Subjects and Methods] Eighteen healthy volunteers participated in the study. Each participant completed tests for peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Results] The results showed (1) a moderate correlation between ankle dorsiflexion range of motion and countermovement jump height and (2) a high correlation between peak first toe flexor muscle strength and countermovement jump height. Peak first toe flexor muscle strength and ankle dorsiflexion range of motion are the main contributors to countermovement jump performance. [Conclusion] These findings indicate that the measurement of peak first toe flexor muscle strength and ankle dorsiflexion range of motion may be useful in clinical practice for improving jump performance in athletes training for sports such as volleyball and basketball.
Giant flux jumps through a thin superconducting Nb film in a vortex free region
International Nuclear Information System (INIS)
Tsindlekht, M.I.; Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N.; Gazi, Š.; Chromik, Š.
2016-01-01
Highlights: Giant magnetic flux jumps into thin-walled cylinder were measured using peak up coil method in a swept magnetic field. Magnetic moment jumps were observed in magnetic fields lower and above Hc1. - Abstract: We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.
Asymptotic Behaviour and Extinction of Delay Lotka-Volterra Model with Jump-Diffusion
Directory of Open Access Journals (Sweden)
Dan Li
2014-01-01
Full Text Available This paper studies the effect of jump-diffusion random environmental perturbations on the asymptotic behaviour and extinction of Lotka-Volterra population dynamics with delays. The contributions of this paper lie in the following: (a to consider delay stochastic differential equation with jumps, we introduce a proper initial data space, in which the initial data may be discontinuous function with downward jumps; (b we show that the delay stochastic differential equation with jumps associated with our model has a unique global positive solution and give sufficient conditions that ensure stochastically ultimate boundedness, moment average boundedness in time, and asymptotic polynomial growth of our model; (c the sufficient conditions for the extinction of the system are obtained, which generalized the former results and showed that the sufficiently large random jump magnitudes and intensity (average rate of jump events arrival may lead to extinction of the population.
Giant flux jumps through a thin superconducting Nb film in a vortex free region
Energy Technology Data Exchange (ETDEWEB)
Tsindlekht, M.I., E-mail: mtsindl@vms.huji.ac.il [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Gazi, Š.; Chromik, Š. [The Institute of Electrical Engineering SAS, Dúbravská cesta 9, 84104 Bratislava (Slovakia)
2016-10-15
Highlights: Giant magnetic flux jumps into thin-walled cylinder were measured using peak up coil method in a swept magnetic field. Magnetic moment jumps were observed in magnetic fields lower and above Hc1. - Abstract: We measure the dynamics of magnetic field penetration into thin-walled superconducting niobium cylinders. It is shown that magnetic field penetrates through the wall of a cylinder in a series of giant jumps with amplitude 1 - 2 mT and duration of less than a microsecond in a wide range of magnetic fields, including the vortex free region. Surprisingly, the jumps take place when the total current in the wall, not the current density, exceeds a critical value. In addition, there are small jumps and/or smooth penetration, but their contribution reaches only ≃ 20 % of the total penetrating flux. The number of jumps decreases with increased temperature. Thermomagnetic instabilities cannot explain the experimental observations.
Maffiuletti, N A; Cometti, G; Amiridis, I G; Martin, A; Pousson, M; Chatard, J C
2000-08-01
The aim of this study was to investigate the influence of a 4-week electromyostimulation training program on the strength of the knee extensors and the vertical jump performance of 10 basketball players. Electromyostimulation sessions were carried out 3 times weekly; each session consisted of 48 contractions. Testing was carried out before and after the electromyostimulation training program (week 4) and once more after 4 weeks of normal basketball training (week 8). At week 4, isokinetic strength increased significantly (p training increased also isometric strength at the two angles adjacent to the training angle (p jump increased significantly by 14% at week 4 (p jump showed no change. At week 8, gains in isokinetic, isometric strength and squat-jump performance were maintained and the counter movement jump performance increased significantly by 17% (ptraining program enhanced knee extensor strength and squat jump performance of basketball players.
Quantum group and quantum symmetry
International Nuclear Information System (INIS)
Chang Zhe.
1994-05-01
This is a self-contained review on the theory of quantum group and its applications to modern physics. A brief introduction is given to the Yang-Baxter equation in integrable quantum field theory and lattice statistical physics. The quantum group is primarily introduced as a systematic method for solving the Yang-Baxter equation. Quantum group theory is presented within the framework of quantum double through quantizing Lie bi-algebra. Both the highest weight and the cyclic representations are investigated for the quantum group and emphasis is laid on the new features of representations for q being a root of unity. Quantum symmetries are explored in selected topics of modern physics. For a Hamiltonian system the quantum symmetry is an enlarged symmetry that maintains invariance of equations of motion and allows a deformation of the Hamiltonian and symplectic form. The configuration space of the integrable lattice model is analyzed in terms of the representation theory of quantum group. By means of constructing the Young operators of quantum group, the Schroedinger equation of the model is transformed to be a set of coupled linear equations that can be solved by the standard method. Quantum symmetry of the minimal model and the WZNW model in conformal field theory is a hidden symmetry expressed in terms of screened vertex operators, and has a deep interplay with the Virasoro algebra. In quantum group approach a complete description for vibrating and rotating diatomic molecules is given. The exact selection rules and wave functions are obtained. The Taylor expansion of the analytic formulas of the approach reproduces the famous Dunham expansion. (author). 133 refs, 20 figs
Tracking an open quantum system using a finite state machine: Stability analysis
International Nuclear Information System (INIS)
Karasik, R. I.; Wiseman, H. M.
2011-01-01
A finite-dimensional Markovian open quantum system will undergo quantum jumps between pure states, if we can monitor the bath to which it is coupled with sufficient precision. In general these jumps, plus the between-jump evolution, create a trajectory which passes through infinitely many different pure states, even for ergodic systems. However, as shown recently by us [Phys. Rev. Lett. 106, 020406 (2011)], it is possible to construct adaptive monitorings which restrict the system to jumping between a finite number of states. That is, it is possible to track the system using a finite state machine as the apparatus. In this paper we consider the question of the stability of these monitoring schemes. Restricting to cyclic jumps for a qubit, we give a strong analytical argument that these schemes are always stable and supporting analytical and numerical evidence for the example of resonance fluorescence. This example also enables us to explore a range of behaviors in the evolution of individual trajectories, for several different monitoring schemes.
Quantum information. Teleportation - cryptography - quantum computer
International Nuclear Information System (INIS)
Koenneker, Carsten
2012-01-01
The following topics are dealt with: Reality in the test facility, quantum teleportation, the reality of quanta, interaction-free quantum measurement, rules for quantum computers, quantum computers with ions, spintronics with diamond, the limits of the quantum computers, a view in the future of quantum optics. (HSI)
Quantum ensembles of quantum classifiers.
Schuld, Maria; Petruccione, Francesco
2018-02-09
Quantum machine learning witnesses an increasing amount of quantum algorithms for data-driven decision making, a problem with potential applications ranging from automated image recognition to medical diagnosis. Many of those algorithms are implementations of quantum classifiers, or models for the classification of data inputs with a quantum computer. Following the success of collective decision making with ensembles in classical machine learning, this paper introduces the concept of quantum ensembles of quantum classifiers. Creating the ensemble corresponds to a state preparation routine, after which the quantum classifiers are evaluated in parallel and their combined decision is accessed by a single-qubit measurement. This framework naturally allows for exponentially large ensembles in which - similar to Bayesian learning - the individual classifiers do not have to be trained. As an example, we analyse an exponentially large quantum ensemble in which each classifier is weighed according to its performance in classifying the training data, leading to new results for quantum as well as classical machine learning.
Quantum computer games: quantum minesweeper
Gordon, Michal; Gordon, Goren
2010-07-01
The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical minesweeper the goal of the game is to discover all the mines laid out on a board without triggering them, in the quantum version there are several classical boards in superposition. The goal is to know the exact quantum state, i.e. the precise layout of all the mines in all the superposed classical boards. The player can perform three types of measurement: a classical measurement that probabilistically collapses the superposition; a quantum interaction-free measurement that can detect a mine without triggering it; and an entanglement measurement that provides non-local information. The application of the concepts taught by quantum minesweeper to one-way quantum computing are also presented.
Quantum Physics Without Quantum Philosophy
Dürr, Detlef; Zanghì, Nino
2013-01-01
It has often been claimed that without drastic conceptual innovations a genuine explanation of quantum interference effects and quantum randomness is impossible. This book concerns Bohmian mechanics, a simple particle theory that is a counterexample to such claims. The gentle introduction and other contributions collected here show how the phenomena of non-relativistic quantum mechanics, from Heisenberg's uncertainty principle to non-commuting observables, emerge from the Bohmian motion of particles, the natural particle motion associated with Schrödinger's equation. This book will be of value to all students and researchers in physics with an interest in the meaning of quantum theory as well as to philosophers of science.
Quantum measurement in quantum optics
International Nuclear Information System (INIS)
Kimble, H.J.
1993-01-01
Recent progress in the generation and application of manifestly quantum or nonclassical states of the electromagnetic field is reviewed with emphasis on the research of the Quantum Optics Group at Caltech. In particular, the possibilities for spectroscopy with non-classical light are discussed both in terms of improved quantitative measurement capabilities and for the fundamental alteration of atomic radiative processes. Quantum correlations for spatially extended systems are investigated in a variety of experiments which utilize nondegenerate parametric down conversion. Finally, the prospects for measurement of the position of a free mass with precision beyond the standard quantum limit are briefly considered. (author). 38 refs., 1 fig
Aerial Rotation Effects on Vertical Jump Performance Among Highly Skilled Collegiate Soccer Players.
Barker, Leland A; Harry, John R; Dufek, Janet S; Mercer, John A
2017-04-01
Barker, LA, Harry, JR, Dufek, JS, and Mercer, JA. Aerial rotation effects on vertical jump performance among highly skilled collegiate soccer players. J Strength Cond Res 31(4): 932-938, 2017-In soccer matches, jumps involving rotations occur when attempting to head the ball for a shot or pass from set pieces, such as corner kicks, goal kicks, and lob passes. However, the 3-dimensional ground reaction forces used to perform rotational jumping tasks are currently unknown. Therefore, the purpose of this study was to compare bilateral, 3-dimensional, and ground reaction forces of a standard countermovement jump (CMJ0) with those of a countermovement jump with a 180° rotation (CMJ180) among Division-1 soccer players. Twenty-four participants from the soccer team of the University of Nevada performed 3 trials of CMJ0 and CMJ180. Dependent variables included jump height, downward and upward phase times, vertical (Fz) peak force and net impulse relative to mass, and medial-lateral and anterior-posterior force couple values. Statistical significance was set a priori at α = 0.05. CMJ180 reduced jump height, increased the anterior-posterior force couple in the downward and upward phases, and increased upward peak Fz (p ≤ 0.05). All other variables were not significantly different between groups (p > 0.05). However, we did recognize that downward peak Fz trended lower in the CMJ0 condition (p = 0.059), and upward net impulse trended higher in the CMJ0 condition (p = 0.071). It was concluded that jump height was reduced during the rotational jumping task, and rotation occurred primarily via AP ground reaction forces through the entire countermovement jump. Coaches and athletes may consider additional rotational jumping in their training programs to mediate performance decrements during rotational jump tasks.
Isokinetic Extension Strength Is Associated With Single-Leg Vertical Jump Height.
Fischer, Felix; Blank, Cornelia; Dünnwald, Tobias; Gföller, Peter; Herbst, Elmar; Hoser, Christian; Fink, Christian
2017-11-01
Isokinetic strength testing is an important tool in the evaluation of the physical capacities of athletes as well as for decision making regarding return to sports after anterior cruciate ligament (ACL) reconstruction in both athletes and the lay population. However, isokinetic testing is time consuming and requires special testing equipment. A single-jump test, regardless of leg dominance, may provide information regarding knee extension strength through the use of correlation analysis of jump height and peak torque of isokinetic muscle strength. Cross-sectional study; Level of evidence, 3. A total of 169 patients who underwent ACL reconstruction were included in this study. Isokinetic testing was performed on the injured and noninjured legs. Additionally, a single-leg countermovement jump was performed to assess jump height using a jump accelerometer sensor. Extension strength values were used to assess the association between isokinetic muscle strength and jump height. The sample consisted of 60 female (mean age, 20.8 ± 8.3 years; mean weight, 61.7 ± 6.5 kg; mean height, 167.7 ± 5.3 cm) and 109 male (mean age, 23.2 ± 7.7 years; mean weight, 74.6 ± 10.2 kg; mean height, 179.9 ± 6.9 cm) patients. Bivariate correlation analysis showed an association ( r = 0.56, P jump height and isokinetic extension strength on the noninvolved side as well as an association ( r = 0.52, P jump height (beta = 0.49, P jump height having the strongest impact (beta = 0.49, P jump height. The study population encompassed various backgrounds, skill levels, and activity profiles, which might have affected the outcome. Even after controlling for age and sex, isokinetic strength was still moderately associated with jump height. Therefore, the jump technique and type of sport should be considered in future research.
Jump Variation Estimation with Noisy High Frequency Financial Data via Wavelets
Directory of Open Access Journals (Sweden)
Xin Zhang
2016-08-01
Full Text Available This paper develops a method to improve the estimation of jump variation using high frequency data with the existence of market microstructure noises. Accurate estimation of jump variation is in high demand, as it is an important component of volatility in finance for portfolio allocation, derivative pricing and risk management. The method has a two-step procedure with detection and estimation. In Step 1, we detect the jump locations by performing wavelet transformation on the observed noisy price processes. Since wavelet coefficients are significantly larger at the jump locations than the others, we calibrate the wavelet coefficients through a threshold and declare jump points if the absolute wavelet coefficients exceed the threshold. In Step 2 we estimate the jump variation by averaging noisy price processes at each side of a declared jump point and then taking the difference between the two averages of the jump point. Specifically, for each jump location detected in Step 1, we get two averages from the observed noisy price processes, one before the detected jump location and one after it, and then take their difference to estimate the jump variation. Theoretically, we show that the two-step procedure based on average realized volatility processes can achieve a convergence rate close to O P ( n − 4 / 9 , which is better than the convergence rate O P ( n − 1 / 4 for the procedure based on the original noisy process, where n is the sample size. Numerically, the method based on average realized volatility processes indeed performs better than that based on the price processes. Empirically, we study the distribution of jump variation using Dow Jones Industrial Average stocks and compare the results using the original price process and the average realized volatility processes.
DEFF Research Database (Denmark)
Wang, Yun; Wu, Qiuwei
2014-01-01
This paper analysis the electromagnetic transient response characteristics of DFIG under symmetrical and asymmetrical cascading grid fault conditions considering phaseangel jump of grid. On deriving the dynamic equations of the DFIG with considering multiple constraints on balanced and unbalanced...... conditions, phase angel jumps, interval of cascading fault, electromagnetic transient characteristics, the principle of the DFIG response under cascading voltage fault can be extract. The influence of grid angel jump on the transient characteristic of DFIG is analyzed and electromagnetic response...
Numerical analysis of the big bounce in loop quantum cosmology
International Nuclear Information System (INIS)
Laguna, Pablo
2007-01-01
Loop quantum cosmology (LQC) homogeneous models with a massless scalar field show that the big-bang singularity can be replaced by a big quantum bounce. To gain further insight on the nature of this bounce, we study the semidiscrete loop quantum gravity Hamiltonian constraint equation from the point of view of numerical analysis. For illustration purposes, we establish a numerical analogy between the quantum bounces and reflections in finite difference discretizations of wave equations triggered by the use of nonuniform grids or, equivalently, reflections found when solving numerically wave equations with varying coefficients. We show that the bounce is closely related to the method for the temporal update of the system and demonstrate that explicit time-updates in general yield bounces. Finally, we present an example of an implicit time-update devoid of bounces and show back-in-time, deterministic evolutions that reach and partially jump over the big-bang singularity
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 9. Quantum Computing - Building Blocks of a Quantum Computer. C S Vijay Vishal Gupta. General Article Volume 5 Issue 9 September 2000 pp 69-81. Fulltext. Click here to view fulltext PDF. Permanent link:
International Nuclear Information System (INIS)
Doplicher, S.
1996-01-01
We review some recent result and work in progress on the quantum structure of spacetime at scales comparable with the Planck length; the models discussed here are operationally motivated by the limitations in the accuracy of localization of events in spacetime imposed by the interplay between quantum mechanics and classical general relativity. (orig.)
Moran, Kevin
2014-01-01
In high-income countries, death as a consequence of recreational jumping into water from height has not been well investigated partly because it traditionally has been a covert activity within youth culture. An observational study of video recordings posted on the YouTube web site was used to gather data on the nature of jumping activity in New Zealand and Australia. An analytical framework was developed to identify site- participant- social characteristics (10 variables) and online feedback (4 variables). Of the 389 videos recorded in New Zealand (n = 210) and Australia (n = 179), 929 jumpers were observed, and rivers were the most frequently reported site of jumping activity (New Zealand 47%; Australia 35%). One fifth (20%) of the jumps in New Zealand and one third (33%) in Australia were from heights estimated to be more than 12 m. The YouTube website portraying jumps from height were visited almost half a million times (495,686 hits). Ways of reducing recreational jumping risk via targeted education interventions may be best directed at young male adults. Use of social network sites to foster safe behaviours may be an effective way to educate young people of the inherent risks of jumping from height into water.
Pearsall, Thomas P
2017-01-01
This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of nonlocality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...
International Nuclear Information System (INIS)
Hawking, S.W.
1984-01-01
The subject of these lectures is quantum effects in cosmology. The author deals first with situations in which the gravitational field can be treated as a classical, unquantized background on which the quantum matter fields propagate. This is the case with inflation at the GUT era. Nevertheless the curvature of spacetime can have important effects on the behaviour of the quantum fields and on the development of long-range correlations. He then turns to the question of the quantization of the gravitational field itself. The plan of these lectures is as follows: Euclidean approach to quantum field theory in flat space; the extension of techniques to quantum fields on a curved background with the four-sphere, the Euclidean version of De Sitter space as a particular example; the GUT era; quantization of the gravitational field by Euclidean path integrals; mini superspace model. (Auth.)
Rae, Alastair I M
2016-01-01
A Thorough Update of One of the Most Highly Regarded Textbooks on Quantum Mechanics Continuing to offer an exceptionally clear, up-to-date treatment of the subject, Quantum Mechanics, Sixth Edition explains the concepts of quantum mechanics for undergraduate students in physics and related disciplines and provides the foundation necessary for other specialized courses. This sixth edition builds on its highly praised predecessors to make the text even more accessible to a wider audience. It is now divided into five parts that separately cover broad topics suitable for any general course on quantum mechanics. New to the Sixth Edition * Three chapters that review prerequisite physics and mathematics, laying out the notation, formalism, and physical basis necessary for the rest of the book * Short descriptions of numerous applications relevant to the physics discussed, giving students a brief look at what quantum mechanics has made possible industrially and scientifically * Additional end-of-chapter problems with...
Richter, Johannes; Farnell, Damian; Bishop, Raymod
2004-01-01
The investigation of magnetic systems where quantum effects play a dominant role has become a very active branch of solid-state-physics research in its own right. The first three chapters of the "Quantum Magnetism" survey conceptual problems and provide insights into the classes of systems considered, namely one-dimensional, two-dimensional and molecular magnets. The following chapters introduce the methods used in the field of quantum magnetism, including spin wave analysis, exact diagonalization, quantum field theory, coupled cluster methods and the Bethe ansatz. The book closes with a chapter on quantum phase transitions and a contribution that puts the wealth of phenomena into the context of experimental solid-state physics. Closing a gap in the literature, this volume is intended both as an introductory text at postgraduate level and as a modern, comprehensive reference for researchers in the field.
Assessment of musculoskeletal system in women with jumping mechanography
Directory of Open Access Journals (Sweden)
Yannis Dionyssiotis
2009-08-01
Full Text Available Yannis Dionyssiotis1,2, Antonios Galanos1, Georgios Michas1, Georgios Trovas1, Georgios P Lyritis11Laboratory for Research of the Musculoskeletal System, University of Athens, KAT Hospital, Kifissia, Greece; 2Rehabilitation Department, Rhodes General Hospital, Rhodes, GreeceAbstract: The purpose of this study was to investigate and add reference data about the musculoskeletal system in women. The mechanography system of the Leonardo™ platform (Novotec, Germany was used to measure parameters of movement (velocity, force, power in 176 healthy Greek women aged 20–79 years, separated according to age decade in six groups: group 1 (n = 12, 20–29 years; group 2 (n = 14, 30–39 years; group 3 (n = 33, 40–49 years; group 4 (n = 59, 50–59 years including 21 postmenopausal; group 5 (n = 31, 60–69 years including 12 postmenopausal; and group 6 (n = 27, 70–79 years all postmenopausal. This system measures forces applied to the plate over time, calculates through acceleration the vertical velocity of center of gravity and using force and velocity it calculates power of vertical movements. All women performed a counter-movement jump (brief squat before the jump with freely moving arms. Weight was recorded on the platform before the jump and height was measured with a wall-mounted ruler. Body weight and body mass index were gradually increased; on the contrary height and all movement parameters except force (velocity, power were statistically decreased during aging and after menopause.Keywords: biomechanics, ground reaction force, power, women, menopause
Motor Control of Landing from a Jump in Simulated Hypergravity.
Directory of Open Access Journals (Sweden)
Clément N Gambelli
Full Text Available On Earth, when landing from a counter-movement jump, muscles contract before touchdown to anticipate imminent collision with the ground and place the limbs in a proper position. This study assesses how the control of landing is modified when gravity is increased above 1 g. Hypergravity was simulated in two different ways: (1 by generating centrifugal forces during turns of an aircraft (A300 and (2 by pulling the subject downwards in the laboratory with a Subject Loading System (SLS. Eight subjects were asked to perform counter-movement jumps at 1 g on Earth and at 3 hypergravity levels (1.2, 1.4 and 1.6 g both in A300 and with SLS. External forces applied to the body, movements of the lower limb segments and muscular activity of 6 lower limb muscles were recorded. Our results show that both in A300 and with SLS, as in 1 g: (1 the anticipation phase is present; (2 during the loading phase (from touchdown until the peak of vertical ground reaction force, lower limb muscles act like a stiff spring, whereas during the second part (from the peak of vertical ground reaction force until the return to the standing position, they act like a compliant spring associated with a damper. (3 With increasing gravity, the preparatory adjustments and the loading phase are modified whereas the second part does not change drastically. (4 The modifications are similar in A300 and with SLS, however the effect of hypergravity is accentuated in A300, probably due to altered sensory inputs. This observation suggests that otolithic information plays an important role in the control of the landing from a jump.
The influence of musical cadence into aquatic jumping jacks kinematics.
Costa, Mário J; Oliveira, Cristiana; Teixeira, Genoveva; Marinho, Daniel A; Silva, António J; Barbosa, Tiago M
2011-01-01
The aim of this study was to analyze the relationships between the head-out aquatic exercise "Jumping jacks" kinematics and the musical cadence in healthy and fit subjects. Five young women, with at least one year of experience conducting head- out aquatic programs were videotaped in the frontal plane, with a pair of cameras providing a double projection (above and below the water surface). Subjects performed an incremental protocol of five bouts (120 b·min(-1), 135 b·min(-1), 150 b·min(-1), 165 b·min(-1) and 180 b·min(-1)) with 16 full cycles of the "Jumping jacks" exercise. Data processing and calculation of upper limbs' (i.e. hands), lower limbs' (i.e. feet) and center of mass' 2D linear velocity and displacement were computed with the software Ariel Performance Analysis System and applying the 2D-DLT algorithm. Subjects decreased the cycle period during the incremental protocol. Significant and negative relationships with the musical cadence were verified for the center of mass and upper limbs vertical displacement. On the other hand, for the lower limbs lateral velocity, a significant and positive relationship was observed. It is concluded that expert and fit subjects increase the lower limb's velocity to maintain the range of motion, while the upper limb's displacement is reduced to coupe the music cadence. Key pointsWhile performing the Jumping Jacks, expert and fit subjects increase their lower limbs segmental velocity to maintain the range of motion.The upper limbs displacement is reduced to maintain the music cadence.Expert and fit subjects present similar response for alternating or simultaneously head-out aquatic exercises when increasing the music cadence.
Universal Earthquake-Occurrence Jumps, Correlations with Time, and Anomalous Diffusion
International Nuclear Information System (INIS)
Corral, Alvaro
2006-01-01
Spatiotemporal properties of seismicity are investigated for a worldwide (WW) catalog and for southern California in the stationary case (SC), showing a nearly universal scaling behavior. Distributions of distances between consecutive earthquakes (jumps) are magnitude independent and show two power-law regimes, separated by jump values about 200 (WW) and 15 km (SC). Distributions of waiting times conditioned to the value of jumps show that both variables are correlated, in general, but turn out to be independent when only short or long jumps are considered. Finally, diffusion profiles are found to be independent on the magnitude, contrary to what the waiting-time distributions suggest