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Sample records for active kinematic constraint

  1. THE EFFECT OF AN ACUTE BOUT OF RUBBER TUBE RUNNING CONSTRAINT ON KINEMATICS AND MUSCLE ACTIVITY

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    Anita Haudum

    2012-09-01

    Full Text Available We examined the effect of an acute bout of treadmill running with rubber tube (RT and without rubber tube (NT elastic constraints on electromyographic (EMG, 3D kinematics variability, and blood lactate concentration (LA. In the RT test, the constraints were attached to the hips and ankles. The selected variables were compared between 30 min of NT running and 30 minutes of RT running in 13 healthy recreationally trained male runners who had no prior exposure to RT. Statistical analysis revealed significantly higher EMG variability (p < 0.01 and muscle activity (p < 0.05 during RT compared to NT that decreased over time approaching NT, indicating movement pattern adaptation. 3D-kinematics and their variability remained generally unaltered. Changes occurred predominantly in the sagittal plane, specifically to the knee and the swing. A significant increase in LA was measured at the end of RT (p < 0.05. These findings suggest that RT running influences muscle recruitment and variability, but has only a minor influence on kinematics. Changes in LA were significant, although relatively small. The observed adaptations in EMG and kinematics suggest that the RTs provide a possibility to create within movement variability in various sports, and thus, variable training conditions may foster strategies to increase the ability to flexibly adapt to different and new situations

  2. New Constraints on the Geometry and Kinematics of Active Faults in the Hinterland of the Northwest Himalaya

    Science.gov (United States)

    Morell, K. D.; Sandiford, M.; Rajendran, C. C. P.; Fink, D.; Kohn, B. P.

    2014-12-01

    The geometry and kinematics of the active, and potentially seismogenic, fault structures within the hinterland of the Himalaya have proven challenging to constrain in the past, primarily because active faults in this region tend to be buried beneath the subsurface and active seismicity often does not align with surficially mapped fault traces. Here we present a series of complementary datasets, including results from low temperature thermochronology, basin-wide erosion rates from 10Be concentrations, and topographic and longitudinal profile analyses, that place constraints on the spatial distribution of fault-related rock uplift and erosion across a ~400-km long region of the lower and high Himalaya of northwest India. Results from our analyses reveal that hillslope morphology and channel steepness are relatively invariant parallel to strike but vary significantly across strike, with the most prominent and abrupt variations occurring at the physiographic transition between the lower and high Himalaya (PT2), near the axial trace of the ramp-flat transition in the Main Himalayan Thrust (MHT). The cross-strike changes in geomorphology observed across the PT2 correlate with an order of magnitude northward increase in basin-wide erosion rates (~0.06-0.8 mm/a) and a corresponding decrease in apatite (~5-2 Ma) and zircon (U-Th)/He (~10-2 Ma) cooling ages. Combined with published geophysical and seismicity data, we interpret these results to reflect spatial variations in rock uplift and exhumation induced by a segment of the MHT ramp-flat system that is at least ~400 km long and ~125 km wide. The relatively young (U-Th)/He ages (flat transition preliminarily suggest that the kinematics of this system are best explained by a model which incorporates an accreting duplex on the MHT ramp but additional forthcoming analyses, including thermal modeling, will confirm if this hypothesis is robust.

  3. Synthetic tsunami waveform catalogs with kinematic constraints

    Science.gov (United States)

    Baptista, Maria Ana; Miranda, Jorge Miguel; Matias, Luis; Omira, Rachid

    2017-07-01

    In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.

  4. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints

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    Kaifei He

    2016-04-01

    Full Text Available When applying the Global Navigation Satellite System (GNSS for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  5. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints.

    Science.gov (United States)

    He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank

    2016-04-01

    When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component.

  6. Inverse Kinematic Control of Humanoids Under Joint Constraints

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    Inhyeok Kim

    2013-01-01

    Full Text Available We propose an inverse kinematic control framework for a position controlled humanoid robot with bounded joint range, velocity, and acceleration limits. The proposed framework comprises two components, an inverse kinematics algorithm and a damping controller. The proposed IKTC (Inverse Kinematics with Task Corrections algorithm is based on the second order task‐ priority method in order to ensure the velocity‐continuity of the solution. When the minimum norm solution exceeds the joint bounds, the problem is treated as a quadratic optimization problem with box constraints; an optimal task correction that lets the solution satisfy the constraints is found. In order to express the three kinds of joint constraints as a second order box constraint, a novel method is also proposed. The joint stiffness of a position controlled humanoid robot necessitates a damping controller to attenuate jolts caused by repeated contacts. We design a damping controller by using an inverted pendulum model with a compliant joint that takes into account the compliance around the foot. By using ZMP [20] measurement, the proposed damping controller is applicable not only in SSP (Single Support Phase but also in DSP (Double Support Phase. The validity of the proposed methods is shown by imitating a captured whole‐body human motion with a position controlled humanoid robot.

  7. Kinematic analysis of recent and active faults of the southern Umbria-Marche domain, Northern Apennines, Italy: geological constraints to geodynamic models

    Science.gov (United States)

    Pasqui, Valeria; Viti, Marcello; Mantovani, Enzo

    2013-04-01

    The recent and active deformation that affects the crest zone of the Umbria-Marche belt (Northern Apennines, Italy) displays a remarkable extensional character, outlined by development of normal fault sets that overprint pre-existing folds and thrusts of Late Miocene-Early Pliocene age. The main extensional fault systems often bound intermontane depressions hosting recent, mainly continental, i.e. fluvial or lacustrine deposits, separating the latter from Triassic-Miocene, mainly carbonatic and siliciclastic marine rocks that belong to the Romagna-Umbria-Marche stratigraphic succession. Stratigraphic data indicate that the extensional strain responsible for the development of normal fault-bounded continental basins in the outer zones of the Northern Apennines was active until Middle Pleistocene time. Since Middle Pleistocene time onwards a major geodynamic change has affected the Central Mediterranean region, with local reorganization of the kinematics in the Adria domain and adjacent Apennine belt. A wide literature illustrates that the overall deformation field of the Central Mediterranean area is presently governed by the relative movements between the Eurasia and Africa plates. The complex interaction of the Africa-Adria and the Anatolian-Aegean-Balkan domains has led the Adria microplate to migrate NW-ward and to collide against Eurasia along the Eastern Southern Alps. As a consequence Adria is presently moving with a general left-lateral displacement with respect to the Apennine mountain belt. The sinistral component of active deformations is also supported by analysis of earthquake focal mechanisms. A comparison between geophysical and geological evidence outlines an apparent discrepancy: most recognized recent and active faults display a remarkable extensional character, as shown by the geometry of continental basin-bounding structutes, whereas geodetic and seismologic evidence indicates the persistency of an active strike-slip, left-lateral dominated

  8. Freeing the Serial Mechanism Designer from Inverse Kinematic Solvability Constraints

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    Diana C. W. Friedman

    2010-01-01

    Full Text Available This paper presents a fast numerical solution for the inverse kinematics of a serial manipulator. The method is implemented on the C-arm, a manipulator designed for use in robotic surgery. The inverse kinematics solution provides all possible solutions for any six degree-of-freedom serial manipulator, assuming that the forward kinematics are known and that it is possible to solve for the remaining joint angles if one joint angle’s value is known. With a fast numerical method and the current levels of computing power, designing a manipulator with closed-form inverse kinematics is no longer necessary. When designing the C-arm, we therefore chose to weigh other factors, such as actuator size and patient safety, more heavily than the ability to find a closed-form inverse kinematics solution.

  9. Online Minimum-acceleration Tra jectory Planning with the Kinematic Constraints

    Institute of Scientific and Technical Information of China (English)

    WANG Ying-Shi; SUN Lei; ZHOU Lu; LIU Jing-Tai

    2014-01-01

    A novel approach based on a type of simplified motion planning (SMP) is presented in this paper to generate online trajectory for manipulator systems with multiple degrees of freedom (DOFs). The key issue is to find minimum-acceleration trajectory planning (MATP) to optimize the arm motion to reduce disturbance. Moreover, necessary and sufficient conditions for solution0s existence subject to all the kinematic constraints of joint position, velocity, acceleration and jerk are devised. Besides, this new method can be activated online from the arbitrary initial state to the arbitrary target state so that it enables the robot to change the original path at any time. Finally, the approach is applied to a real humanoid robot arm with seven DOFs to show its efficiency.

  10. Human Hand Kinematic Modeling Based on Robotic Concepts for Digit Animation with Dynamic Constraints

    Science.gov (United States)

    Tondu, Bertrand

    The recent development of highly anthropomorphic avatars in computer graphics has emphasized the importance of accurate hand kinematic models. Although kinematic methods derived from robotics have recently been applied to the modeling of hands, we consider that original/new and relevant results can be brought into play with the use of more advanced applications of robotic techniques to human hand kinematic modeling. Our chapter analyses some of these questions both in the non-differential and differential fields. More specifically, we study how to integrate the peculiar natural digit movement constraints into robotics-based inverse kinematic modeling. As a result, we propose an original approach based on an interpretation of each joint dynamic constraint as a linear joint synergy. This leads to defining the considered digit as a serial chain kinematically redundant in position and reducing the dimension of its joint space by associated joint synergies. The method is applied to the Cartesian positioning simulation of a 4 d.o.f. index model; a comparison with a Jacobian pseudo-inverse-based approach emphasizes its relevance.

  11. Impact mitigation using kinematic constraints and the full space parameterization method

    Energy Technology Data Exchange (ETDEWEB)

    Morgansen, K.A.; Pin, F.G.

    1996-02-01

    A new method for mitigating unexpected impact of a redundant manipulator with an object in its environment is presented. Kinematic constraints are utilized with the recently developed method known as Full Space Parameterization (FSP). System performance criterion and constraints are changed at impact to return the end effector to the point of impact and halt the arm. Since large joint accelerations could occur as the manipulator is halted, joint acceleration bounds are imposed to simulate physical actuator limitations. Simulation results are presented for the case of a simple redundant planar manipulator.

  12. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

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    Heo, Yonggoo; Lutz, Matthias F.M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2014-08-15

    We consider the reaction dynamics of bosons with negative parity and spin 0 or 1 and fermions with positive parity and spin (1)/(2) or (3)/(2). Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersion-integral representation is prohibitively cumbersome. We derive covariant partial-wave amplitudes that are free from kinematical constraints at the Kibble conditions. They correspond to specific polynomials in the 4-momenta and Dirac matrices that solve the various Bethe-Salpeter equations in the presence of short-range interactions analytically. (orig.)

  13. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

    Science.gov (United States)

    Heo, Yonggoo; Lutz, Matthias F. M.

    2014-08-01

    We consider the reaction dynamics of bosons with negative parity and spin 0 or 1 and fermions with positive parity and spin or . Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersion-integral representation is prohibitively cumbersome. We derive covariant partial-wave amplitudes that are free from kinematical constraints at the Kibble conditions. They correspond to specific polynomials in the 4-momenta and Dirac matrices that solve the various Bethe-Salpeter equations in the presence of short-range interactions analytically.

  14. New morphotectonics constraints on the present-day kinematics of the Rif region, Morocco

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    Poujol, Antoine; Ritz, Jean-Francois; Tahayt, Abdelilah; Vernant, Philippe; Condomines, Michel; Billant, Jeremy

    2013-04-01

    We present results of a geomorphological and morphotectectonic analysis of the Rif. Our study area encompasses a region running from the eastern border of the Rif up to the Atlantic coast to the west, and including the southwestern foreland of the range. We show that the present day kinematics of the Rif is characterized by active deformations along the Trougout and Nekor faults in the North-East. DEMs of offset drainage features (streams, fluvial terraces) allow determining a normal-left-lateral motion along the Trougout fault and a left-lateral motion along the Nekor fault. Along its southern front, the Rif is characterized by thrusting associated with the E-W trending Jabal Zalagh structure. Uplifted marine terraces near the Al Hoceima Bay are consistent with the present-day localized transtension seen in the morphology in the north-eastern Rif (Rastarf). U/Th dating of shells yield an average uplift rate of 0.34±0.02 mm/yr from 330.000 years and a minimum uplift of 0.1 ±0.05 mm/yr during the past 59.000 years. On the other hand, no active uplift is observed along the Atlantic coast. We also observed strong incisions features (abandoned strath terraces, perched valleys) everywhere inside the northern Rif suggesting that active faulting in the Rif is also associated with uplift of the range. These new morphotectonics constraints are consistent with the GPS measurements showing a south-westwards overall motion of most of the Rif belt with respect to stable Africa.

  15. On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum

    CERN Document Server

    Heo, Yonggoo

    2014-01-01

    We consider the reaction dynamics of bosons with negative parity and spin $0$ or $1$ and fermions with positive parity and spin $\\frac{1}{2}$ or $\\frac{3}{2}$. Such systems are of central importance for the computation of the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral Lagrangian the coupled-channel partial-wave scattering amplitudes have to be computed. We study the generic properties of such amplitudes. A decomposition of the various scattering amplitudes into suitable sets of invariant functions expected to satisfy Mandelstam's dispersion-integral representation is presented. Sets are identified that are free from kinematical constraints and that can be computed efficiently in terms of a novel projection algebra. From such a representation one can deduce the analytic structure of the partial-wave amplitudes. The helicity and the conventional angular-momentum partial-wave amplitudes are kinematically constrained at the Kibble conditions. Therefore an application of a dispersi...

  16. Constraint Study for a Hand Exoskeleton: Human Hand Kinematics and Dynamics

    Directory of Open Access Journals (Sweden)

    Fai Chen Chen

    2013-01-01

    Full Text Available In the last few years, the number of projects studying the human hand from the robotic point of view has increased rapidly, due to the growing interest in academic and industrial applications. Nevertheless, the complexity of the human hand given its large number of degrees of freedom (DoF within a significantly reduced space requires an exhaustive analysis, before proposing any applications. The aim of this paper is to provide a complete summary of the kinematic and dynamic characteristics of the human hand as a preliminary step towards the development of hand devices such as prosthetic/robotic hands and exoskeletons imitating the human hand shape and functionality. A collection of data and constraints relevant to hand movements is presented, and the direct and inverse kinematics are solved for all the fingers as well as the dynamics; anthropometric data and dynamics equations allow performing simulations to understand the behavior of the finger.

  17. A Smooth Tour Construction Approach for a Mobile Robot with Kinematic Constraints

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    Ahmet Yazici

    2013-10-01

    Full Text Available Mobile robots are increasingly used for service-like applications in which the service points are known and the mobile robot starts from a starting location, visits all the service points requested and returns to the starting location. The tour construction problem in these applications can be treated as a Travelling Salesman Problem (TSP. Classical tour construction algorithms that are proposed for the TSP find tours do not consider robot kinematic constraints. These tours may have sharp turns at some service points. When a mobile robot follows such a tour, it stops, turns and speeds up again. Therefore, the robots waste a considerable amount of power and time. In these cases, tour smoothing can be used to overcome this problem. However, smoothing an existing tour may result in unnecessarily long tours. In this study, a Smooth Tour Construction (STC approach is proposed for mobile robots with kinematic constraints. The STC approach considers tour construction and tour smoothing concurrently. The logic behind the tour construction part of the approach is based on the Savings Algorithm (SA. The tour smoothing is based on Dubins’ arc-line approach. Experiments are conducted for P3-DX robots in a laboratory environment. Comparisons are also drawn with various tour smoothing algorithms in simulation environments to demonstrate the effectiveness of the proposed STC approach.

  18. Monte Carlo comparisons of the top quark mass measurement techniques using kinematic constraints

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    Ryu, Geonmo; Kim, Ji Hyun; Lee, Jason Sang Hun; Park, Inkyu

    2016-12-01

    A Monte Carlo study to compare the sensitivities of the top-quark mass-reconstruction methods using the b-quark decay as a kinematic constraint was performed. The top quark is reconstructed from its decay products, the W boson and the b-quark, and its mass can be obtained by using the 4-vector sum of their final states. However, missing neutrinos and the poor jet energy resolution makes the mass measurement biased and imprecise, always requiring further calibration, and dominates the systematic uncertainties. Several new ideas to increase the mass resolution by using the kinematic constraints of the b quark decays using a charm quark meson were suggested and performed to overcome such systematic limits. In this study, we compare three methods, one using J/ ψ, another using D 0, and the other using D* meson, by extracting their sensitivities to the top-quark mass, as well as their statistical advantages. This study is intended to set a priority in the real data analyses using a new data set from abundant tbar t production in the Large Hadron Collider (LHC) Run 2.

  19. Sampling-based exploration of folded state of a protein under kinematic and geometric constraints

    KAUST Repository

    Yao, Peggy

    2011-10-04

    Flexibility is critical for a folded protein to bind to other molecules (ligands) and achieve its functions. The conformational selection theory suggests that a folded protein deforms continuously and its ligand selects the most favorable conformations to bind to. Therefore, one of the best options to study protein-ligand binding is to sample conformations broadly distributed over the protein-folded state. This article presents a new sampler, called kino-geometric sampler (KGS). This sampler encodes dominant energy terms implicitly by simple kinematic and geometric constraints. Two key technical contributions of KGS are (1) a robotics-inspired Jacobian-based method to simultaneously deform a large number of interdependent kinematic cycles without any significant break-up of the closure constraints, and (2) a diffusive strategy to generate conformation distributions that diffuse quickly throughout the protein folded state. Experiments on four very different test proteins demonstrate that KGS can efficiently compute distributions containing conformations close to target (e.g., functional) conformations. These targets are not given to KGS, hence are not used to bias the sampling process. In particular, for a lysine-binding protein, KGS was able to sample conformations in both the intermediate and functional states without the ligand, while previous work using molecular dynamics simulation had required the ligand to be taken into account in the potential function. Overall, KGS demonstrates that kino-geometric constraints characterize the folded subset of a protein conformation space and that this subset is small enough to be approximated by a relatively small distribution of conformations. © 2011 Wiley Periodicals, Inc.

  20. Human-robot interaction: kinematics and muscle activity inside a powered compliant knee exoskeleton.

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    Knaepen, Kristel; Beyl, Pieter; Duerinck, Saartje; Hagman, Friso; Lefeber, Dirk; Meeusen, Romain

    2014-11-01

    Until today it is not entirely clear how humans interact with automated gait rehabilitation devices and how we can, based on that interaction, maximize the effectiveness of these exoskeletons. The goal of this study was to gain knowledge on the human-robot interaction, in terms of kinematics and muscle activity, between a healthy human motor system and a powered knee exoskeleton (i.e., KNEXO). Therefore, temporal and spatial gait parameters, human joint kinematics, exoskeleton kinetics and muscle activity during four different walking trials in 10 healthy male subjects were studied. Healthy subjects can walk with KNEXO in patient-in-charge mode with some slight constraints in kinematics and muscle activity primarily due to inertia of the device. Yet, during robot-in-charge walking the muscular constraints are reversed by adding positive power to the leg swing, compensating in part this inertia. Next to that, KNEXO accurately records and replays the right knee kinematics meaning that subject-specific trajectories can be implemented as a target trajectory during assisted walking. No significant differences in the human response to the interaction with KNEXO in low and high compliant assistance could be pointed out. This is in contradiction with our hypothesis that muscle activity would decrease with increasing assistance. It seems that the differences between the parameter settings of low and high compliant control might not be sufficient to observe clear effects in healthy subjects. Moreover, we should take into account that KNEXO is a unilateral, 1 degree-of-freedom device.

  1. The overmassive black hole in NGC 1277: new constraints from molecular gas kinematics

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    Scharwächter, J.; Combes, F.; Salomé, P.; Sun, M.; Krips, M.

    2016-04-01

    We report the detection of CO(1-0) emission from NGC 1277, a lenticular galaxy in the Perseus Cluster. NGC 1277 has previously been proposed to host an overmassive black hole (BH) compared to the galaxy bulge luminosity (mass), based on stellar-kinematic measurements. The CO(1-0) emission, observed with the IRAM Plateau de Bure Interferometer (PdBI) using both, a more compact (2.9-arcsec resolution) and a more extended (1-arcsec resolution) configuration, is likely to originate from the dust lane encompassing the galaxy nucleus at a distance of 0.9 arcsec (˜320 pc). The double-horned CO(1-0) profile found at 2.9-arcsec resolution traces 1.5 × 108 M⊙ of molecular gas, likely orbiting in the dust lane at ˜550 km s-1, which suggests a total enclosed mass of ˜2 × 1010 M⊙. At 1-arcsec resolution, the CO(1-0) emission appears spatially resolved along the dust lane in east-west direction, though at a low signal-to-noise ratio. In agreement with the previous stellar-kinematic measurements, the CO(1-0) kinematics is found to be consistent with an ˜1.7 × 1010 M⊙ BH for a stellar mass-to-light ratio of M/LV = 6.3, while a less massive BH of ˜5 × 109 M⊙ is possible when assuming a larger M/LV = 10. While the molecular gas reservoir may be associated with a low level of star formation activity, the extended 2.6-mm continuum emission is likely to originate from a weak AGN, possibly characterized by an inverted radio-to-millimetre spectral energy distribution. Literature radio and X-ray data indicate that the BH in NGC 1277 is also overmassive with respect to the Fundamental Plane of BH activity.

  2. Patterns of thermal constraint on ectotherm activity.

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    Gunderson, Alex R; Leal, Manuel

    2015-05-01

    Thermal activity constraints play a major role in many aspects of ectotherm ecology, including vulnerability to climate change. Therefore, there is strong interest in developing general models of the temperature dependence of activity. Several models have been put forth (explicitly or implicitly) to describe such constraints; nonetheless, tests of the predictive abilities of these models are lacking. In addition, most models consider activity as a threshold trait instead of considering continuous changes in the vigor of activity among individuals. Using field data for a tropical lizard (Anolis cristatellus) and simulations parameterized by our observations, we determine how well various threshold and continuous-activity models match observed activity patterns. No models accurately predicted activity under all of the thermal conditions that we considered. In addition, simulations showed that the performance of threshold models decreased as temperatures increased, which is a troubling finding given the threat of global climate change. We also find that activity rates are more sensitive to temperature than are the physiological traits often used as a proxy for fitness. We present a model of thermal constraint on activity that integrates aspects of both the threshold model and the continuous-activity model, the general features of which are supported by activity data from other species. Overall, our results demonstrate that greater attention should be given to fine-scale patterns of thermal constraint on activity.

  3. Effects of load on good morning kinematics and EMG activity.

    Science.gov (United States)

    Vigotsky, Andrew David; Harper, Erin Nicole; Ryan, David Russell; Contreras, Bret

    2015-01-01

    Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  4. Effects of load on good morning kinematics and EMG activity

    Directory of Open Access Journals (Sweden)

    Andrew David Vigotsky

    2015-01-01

    Full Text Available Many strength and conditioning coaches utilize the good morning (GM to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flexion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.

  5. Geotectonic Elements, Stuctural Constraints and Current Problems for a Kinematic Reconstruction of the Caribbean Plate Margins during the Cretaceous.

    Science.gov (United States)

    Giunta, G.

    2001-12-01

    blocks; (2) the sinking direction of the previously subducted oceanic slabs; (3) the locations of and relationships between the intraoceanic and sub-continental subduction zones. Taking this points into account and on the basis of the new geological constraints, some alternative tectonic models can be elaborated, each of which needs kinematic releases (strike-slip faults) allowing either the simultaneous activation of intraoceanic and sub-continental collisions, or the progressive insertion by tectonic erosion of the rifted continental portions in the subduction complexes. In a whole transpressional regime the different subduction zones can be inferred to dip either eastward with a later flip westward below the oceanic plateau, or continuously westward; this last case is a better fit for the Northern margin than the Southern margin of the Caribbean plate, where a much more complicated kinematic mechanism should be envisaged. * Researches carried-out in the framework of the IGCP 433 "Caribbean Plate Tectonics".

  6. Institutional Constraints, Legislative Activism and Policy Change

    DEFF Research Database (Denmark)

    Citi, Manuele; Justesen, Mogens Kamp

    2016-01-01

    This article presents a study of how institutional constraints affect legislative activism and how legislative activism in turn affects policy change through an analysis of the European Union's legislative process. The argument revolves around the key role of the European Commission in advancing ...

  7. Effects of constraint-induced therapy combined with eye patching on functional outcomes and movement kinematics in poststroke neglect.

    Science.gov (United States)

    Wu, Ching-Yi; Wang, Tien-Ni; Chen, Yu-Ting; Lin, Keh-Chung; Chen, Yi-An; Li, Hsiang-Ting; Tsai, Pei-Luen

    2013-01-01

    OBJECTIVE. We investigated the effect of constraint-induced therapy (CIT) plus eye patching (EP), CIT alone, and conventional treatment on functional performance, eye movement, and trunk-arm kinematics in stroke patients with neglect syndrome. METHOD. Twenty-four participants were recruited and randomly allocated to three intervention groups. All participants received intervention 2 hr/day, 5 days/wk, for 3 wk. Outcome measures included the Catherine Bergego Scale, eye movement, and trunk-arm kinematic analysis. RESULTS. The CIT + EP and CIT groups demonstrated larger improvements in functional performance than the control group. The CIT group showed better performance with left fixation points than the CIT+EP group and shorter reaction time than the control group. The CIT + EP group improved more in preplanned control and leftward trunk shift than the other two groups. CONCLUSION. CIT + EP and CIT were more effective interventions than conventional treatment of patients with neglect syndrome in daily functional performance.

  8. CLASH-VLT: constraints on f(R) gravity models with galaxy clusters using lensing and kinematic analyses

    Science.gov (United States)

    Pizzuti, L.; Sartoris, B.; Amendola, L.; Borgani, S.; Biviano, A.; Umetsu, K.; Mercurio, A.; Rosati, P.; Balestra, I.; Caminha, G. B.; Girardi, M.; Grillo, C.; Nonino, M.

    2017-07-01

    We perform a maximum likelihood kinematic analysis of the two dynamically relaxed galaxy clusters MACS J1206.2-0847 at z=0.44 and RXC J2248.7-4431 at z=0.35 to determine the total mass profile in modified gravity models, using a modified version of the MAMPOSSt code of Mamon, Biviano and Bou&apose. Our work is based on the kinematic and lensing mass profiles derived using the data from the Cluster Lensing And Supernova survey with Hubble (hereafter CLASH) and the spectroscopic follow-up with the Very Large Telescope (hereafter CLASH-VLT). We assume a spherical Navarro-Frenk-White (NFW hereafter) profile in order to obtain a constraint on the fifth force interaction range λ for models in which the dependence of this parameter on the environment is negligible at the scale considered (i.e. λ=const) and fixing the fifth force strength to the value predicted in f(R) gravity. We then use information from lensing analysis to put a prior on the other NFW free parameters. In the case of MACSJ 1206 the joint kinematic+lensing analysis leads to an upper limit on the effective interaction range λdistribution. For RXJ 2248 instead a possible tension with the ΛCDM model appears when adding lensing information, with a lower limit λ>=0.14 mpc at Δχ2=2.71. This is consequence of the slight difference between the lensing and kinematic data, appearing in GR for this cluster, that could in principle be explained in terms of modifications of gravity. We discuss the impact of systematics and the limits of our analysis as well as future improvements of the results obtained. This work has interesting implications in view of upcoming and future large imaging and spectroscopic surveys, that will deliver lensing and kinematic mass reconstruction for a large number of galaxy clusters.

  9. Kinematics Card Sort Activity: Insight into Students' Thinking

    Science.gov (United States)

    Berryhill, Erin; Herrington, Deborah; Oliver, Keith

    2016-12-01

    Kinematics is a topic students are unknowingly aware of well before entering the physics classroom. Students observe motion on a daily basis. They are constantly interpreting and making sense of their observations, unintentionally building their own understanding of kinematics before receiving any formal instruction. Unfortunately, when students take their prior conceptions to understand a new situation, they often do so in a way that inaccurately connects their learning. We were motivated to identify strategies to help our students make accurate connections to their prior knowledge and understand kinematics at a deeper level. To do this, we integrated a formative assessment card sort into a kinematic graphing unit within an introductory high school physics course. Throughout the activities, we required students to document and reflect upon their thinking. This allowed their learning to build upon their own previously held conceptual understanding, which provided an avenue for cognitive growth. By taking a more direct approach to eliciting student reasoning, we hoped to improve student learning and guide our assessment of their learning.

  10. Muscle activity and kinematics of forefoot and rearfoot strike runners

    OpenAIRE

    Ahn, A. N.; C. Brayton; Bhatia, T.; P.; Martin

    2014-01-01

    Background: Forefoot strike (FFS) and rearfoot strike (RFS) runners differ in their kinematics, force loading rates, and joint loading patterns, but the timing of their muscle activation is less clear. Methods: Forty recreational and highly trained runners ran at four speeds barefoot and shod on a motorized treadmill. “Barefoot” runners wore thin, five-toed socks and shod runners wore neutral running shoes. Subjects were instructed to run comfortably at each speed with no instructions abou...

  11. High-Redshift Galaxy Kinematics: Constraints on Models of Disk Formation

    CERN Document Server

    Robertson, Brant E

    2008-01-01

    Integral field spectroscopy of galaxies at redshift z~2 has revealed a population of early-forming, rotationally-supported disks. These high-redshift systems provide a potentially important clue to the formation processes that build disk galaxies in the universe. A particularly well-studied example is the z=2.38 galaxy BzK-15504, which was shown by Genzel et al. (2006) to be a rotationally supported disk despite the fact that its high star formation rate and short gas consumption timescale require a very rapid acquisition of mass. Previous kinematical analyses have suggested that z~2 disk galaxies like BzK-15504 did not form through mergers because their line-of-sight velocity fields display low levels of asymmetry. We perform the same kinematical analysis on a set of simulated disk galaxies formed in gas-rich mergers of the type that may be common at high redshift, and show that the remnant disks display low velocity field asymmetry and satisfy the criteria that have been used to classify high-redshift galax...

  12. Kinematic and Chemical constraints on the formation of M31's inner and outer halo

    CERN Document Server

    Koch, A; Reitzel, D; Martin, N F; Ibata, R A; Chapman, S C; Majewski, S R; Mori, M; Loh, Y -S; Ostheimer, J C

    2007-01-01

    The halo of M31 shows a wealth of substructures that are consistent with satellite accretion. Here we report on kinematic and abundance results from Keck/DEIMOS spectroscopy in the calcium triplet region of over 3500 red giant star candidates along the minor axis and in off-axis spheroid fields of M31. Our data reach out to large radial distances of 160 kpc. The derived velocity distributions show a kinematically cold substructure at 17 kpc that has been reported before. We devise an improved method to measure accurate metallicities from the calcium triplet in low signal-to-noise spectra using a coaddition of the individual lines. The resulting distribution leads us to note an even stronger gradient in the abundance distribution along M31's minor axis than previously detected. The mean metallicity in the outer halo reaches below -2 dex, with individual values as low as -2.6 dex. In the inner spheroid, at 17-19 kpc, we find a sharp decline of ~0.5 dex in metallicity, which roughly coincides with the edge of an...

  13. The over-massive black hole in NGC 1277: New constraints from molecular gas kinematics

    CERN Document Server

    Scharwächter, J; Salomé, P; Sun, M; Krips, M

    2015-01-01

    We report the detection of CO(1-0) emission from NGC 1277, a lenticular galaxy in the Perseus Cluster, which has been proposed to host a $(1.3-1.7) \\times 10^{10}\\ M_\\odot$ black hole (BH) based on stellar kinematic measurements. The CO(1-0) emission, observed with the IRAM Plateau de Bure Interferometer (PdBI) using both, a more extended (~1-arcsec resolution) and a more compact (~2.5-arcsec resolution) configuration, is likely to originate from the dust lane encompassing the galaxy nucleus at a distance of 0.9 arcsec (~320 pc). The spatially-unresolved double-horned CO(1-0) profile found at 2.5-arcsec resolution is likely to trace gas orbiting in the dust lane with rotational velocities of ~520 km s$^{-1}$, indicative of an enclosed mass of ~$2 \\times 10^{10}\\ M_\\odot$. Based on models with realistic mass distributions, the CO(1-0) kinematics is found to be consistent with a ~$1.7 \\times 10^{10}\\ M_\\odot$ BH, while a less massive BH is still possible assuming a large stellar mass-to-light ratio. The stronge...

  14. OPTIMASS: A Package for the Minimization of Kinematic Mass Functions with Constraints

    CERN Document Server

    Cho, Won Sang; Kim, Doojin; Lim, Sung Hak; Matchev, Konstantin T; Moortgat, Filip; Pape, Luc; Park, Myeonghun

    2015-01-01

    Reconstructed mass variables, such as $M_2$, $M_{2C}$, $M_T^\\star$, and $M_{T2}^W$, play an essential role in searches for new physics at hadron colliders. The calculation of these variables generally involves constrained minimization in a large parameter space, which is numerically challenging. We provide a C++ code, OPTIMASS, which interfaces with the MINUIT library to perform this constrained minimization using the Augmented Lagrangian Method. The code can be applied to arbitrarily general event topologies and thus allows the user to significantly extend the existing set of kinematic variables. We describe this code and its motivation and demonstrate its use in the analysis of the fully leptonic decay of pair-produced top quarks using the $M_2$ variables.

  15. Geologic constraints on kinematic models and age of formation of the Amerasia Basin of the Arctic

    Science.gov (United States)

    Miller, E. L.

    2015-12-01

    A wealth of new geologic and geophysical data now exist for the Amerasia Basin, but the details of its age and the nature/kinematics of events that resulted in its formation remain elusive. Basement rock ages, detrital zircon signatures of sedimentary rocks, and sediment dispersal systems have been used to show how parts of the southern margin(s) of the Amerasia Basin (Arctic Alaska-Chukotka, AAC) match their rifted margin counterparts on the Eurasia and Canada side of the Amerasia Basin. Thus we know the approximate finite translations needed to restore the paleogeography of the Arctic, but not the kinematics involved. Important features of the Amerasia Basin that need to be explained in a model for its opening are the age and extent of the high Arctic LIP, the linearity of the strip of continental crust represented by the Lomonosov Ridge, its right angle intersection with the Canadian Arctic margin, and the directional fault patterns mapped bathymetrically and seismically across the Alpha-Lomonosov Ridge and surrounding seafloor. Across AAC, post-Early Cretaceous oroclinal bends provide insight into strike-slip components of deformation involved in opening of the Amerasia Basin: The Chukchi syntax offsets the Brooks Range in a right-lateral sense from Wrangel Island along the Herald Arch; right-lateral motion of Arctic Alaska with respect to the Chukchi Borderland during opening of the Canada Basin; right-lateral shear in Chukotka during 100 Ma magmatism; the tight bend in the northern Verkhoyansk, result of Cretaceous right-lateral shear. The land-based relationships imply a post-Early Cretaceous, younger than Barremian (~130 Ma) age for onset of magmatism and extension related to rifting and formation of the Amerasia Basin. At least two stages of extension are documented, with older E-W extension characterizing the longitude of the New Siberian Islands to Pevek, Russian Arctic, (ca.125 Ma to 100 Ma), with younger N-S extension superimposed on this system (ca

  16. The APOSTLE project: Local Group kinematic mass constraints and simulation candidate selection

    CERN Document Server

    Fattahi, Azadeh; Sawala, Till; Frenk, Carlos S; Oman, Kyle A; Crain, Robert A; Furlong, Michelle; Schaller, Matthieu; Schaye, Joop; Theuns, Tom; Jenkins, Adrian

    2015-01-01

    We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group of Galaxies (LG). We find, in agreement with the "timing argument" and earlier work, that the separation and approach velocity of the Milky Way (MW) and Andromeda (M31) galaxies favour a total mass for the pair of ~ 5*10^12 M_sun. A mass this large, however, is difficult to reconcile with the small relative tangential velocity of the pair, as well as with the small deceleration from the Hubble flow observed for the most distant LG members. Halo pairs that match these three criteria have average masses a factor of ~2 times smaller than suggested by the timing argument, but with large dispersion, spanning more than a decade in mass. Guided by these results, we have selected 12 halo pairs with total mass in the range 1.6-3.6 *10^12 M_sun for the APOSTLE project (A Project Of Simulations of The Local Environment), a suite of resimulations ...

  17. Kinematic constraints on buckling a lithospheric-scale orocline during Pangea assembly: a geologic synthesis

    Science.gov (United States)

    Weil, Arlo; Gutiérrez-Alonso, Gabriel; Johnston, Stephen; Pastor Galán, Daniel

    2013-04-01

    The Paleozoic Variscan orogeny was a large-scale collisional event involving amalgamation of multiple continents and micro-continents. Existing data, suggests oroclinal buckling of an originally near-linear convergent margin during the last stages of Variscan deformation in the late Paleozoic. Closure of the Rheic Ocean resulted in E-W shortening (present-day coordinates) in the Carboniferous, producing a near linear N-S trending, east-verging belt. Subsequent N-S shortening near the Carb-Permian boundary resulted in oroclinal buckling. This late-stage orogenic event remains an enigmatic part of final Pangea amalgamation. The present-day arc curvature of the Variscan has inspired many tectonic models, with little agreement between them. While there is general consensus that two separate phases of deformation occurred, various models consider that curvature was caused by: dextral transpression around a Gondwana indentor; strike-slip wrench tectonics; or a change in tectonic transport direction due to changing stress fields. More recent models explain the curvature as an orocline, with potentially two opposite-facing bends, caused by secondary rotations. Deciphering the kinematic history of curved orogens is difficult, and requires establishment of two deformation phases: an initial compressive phase that forms a relatively linear belt, and a second phase that causes vertical-axis rotation of the orogenic limbs. Historically the most robust technique to accurately quantify vertical axis-rotation in curved orogens is paleomagnetic analysis, but recently other types of data, including fracture, geochemical, petrologic, paleo-current and calcite twin data, have been used to corroborate secondary buckling. A review of existing and new Variscan data from Iberia is presented that argues for secondary buckling of an originally linear orogenic system. Together, these data constrain oroclinal buckling of the Cantabrian Orocline to have occurred in about 10 Ma during the

  18. Solar Nebula Magnetohydrodynamic Dynamos: Kinematic Theory, Dynamical Constraints, and Magnetic Transport of Angular Momentum

    Science.gov (United States)

    Stepinski, Tomasz F.; Reyes-Ruiz, Mauricio; Vanhala, Harri A. T.

    1993-01-01

    A hydromagnetic dynamo provides the best mechanism for contemporaneously producing magnetic fields in a turbulent solar nebula. We investigate the solar nebula in the framework of a steady-state accretion disk model and establish the criteria for a viable nebular dynamo. We have found that typically a magnetic gap exists in the nebula, the region where the degree of ionization is too small for the magnetic field to couple to the gas. The location and width of this gap depend on the particular model; the supposition is that gaps cover different parts of the nebula at different evolutionary stages. We have found, from several dynamical constraints, that the generated magnetic field is likely to saturate at a strength equal to equipartition with the kinetic energy of turbulence. Maxwell stress arising from a large-scale magnetic field may significantly influence nebular structure, and Maxwell stress due to small-scale fields can actually dominate other stresses in the inner parts of the nebula. We also argue that the bulk of nebular gas, within the scale height from the midplane, is stable against Balbus-Hawley instability.

  19. A Four-Dimensional {\\Lambda}CDM-Type Cosmological Model Induced from Higher Dimensions Using a Kinematical Constraint

    CERN Document Server

    Akarsu, Ozgur

    2013-01-01

    A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes the direct sum of a 3-dimensional (physical, flat) external space metric and an n-dimensional (compact, flat) internal space metric. A simple kinematical constraint is postulated that correlates the expansion rates of the external and internal spaces in terms of a real parameter \\lambda. A specific solution for which both the external and internal spaces expand at different rates is given analytically for n=3. Assuming that the internal dimensions were at Planck length scales at the beginning t=0, the external space starts with a Big Bang and the external and internal spaces both reach the same size after 10^{-176} Gyr. Then during the lifetime of the observed universe (13.7 Gyr), the external dimensions would expand 10^{59} times while the internal dimensions expand only 1.49 times. The effectiv...

  20. Progressive migration of slab break-off along the southern Tyrrhenian plate boundary: Constraints for the present day kinematics

    Science.gov (United States)

    Chiarabba, Claudio; Palano, Mimmo

    2017-04-01

    The Ionian subduction in the central Mediterranean, just 200 km wide, is one of the narrowest in the world. Its evolution has involved a progressive disruption of the subducting slab, contemporaneous to the retreat and step-wise opening of back-arc basins. In this study, we analyse velocity anomalies of the upper mantle, together with the most comprehensive set of earthquake locations and kinematic indicators available for Italy, to reconstruct the geodynamics and tectonic evolution of the Ionian subduction system. Along the Sicilian boundary, we identify an eastward migration of the slab edge with detachment of the Ionian oceanic lithosphere. We hypothesize that the progressive detachment of the slab took place along lithospheric transform faults of the Neo-Tethys Ocean. Among the main active kinematic elements of the Ionian accretionary wedge, we suggest that a ∼400-km-long and highly segmented shear zone formed by the Aeolian-Tindari-Letojanni fault system and the Ionian fault represents the surface expression of such a lithospheric tearing. The present day convergence between the Eurasian and African plates is accommodated both at the frontal thrust of the flexed Hyblean margin in southern Sicily and offshore along the Tyrrhenian Sea. Lithospheric bending favors the wedging of the mantle underneath northern Sicily, while magmatic fluids are channeled along slab tears.

  1. Kinematics, muscular activity and propulsion in gopher snakes

    Science.gov (United States)

    Moon; Gans

    1998-10-01

    Previous studies have addressed the physical principles and muscular activity patterns underlying terrestrial lateral undulation in snakes, but not the mechanism by which muscular activity produces curvature and propulsion. In this study, we used synchronized electromyography and videography to examine the muscular basis and propulsive mechanism of terrestrial lateral undulation in gopher snakes Pituophis melanoleucus affinis. Specifically, we used patch electrodes to record from the semispinalis, longissimus dorsi and iliocostalis muscles in snakes pushing against one or more pegs. Axial bends propagate posteriorly along the body and contact the pegs at or immediately posterior to an inflection of curvature, which then reverses anterior to the peg. The vertebral column bends broadly around a peg, whereas the body wall bends sharply and asymmetrically around the anterior surface of the peg. The epaxial muscles are always active contralateral to the point of contact with a peg; they are activated slightly before or at the point of maximal convexity and deactivated variably between the inflection point and the point of maximal concavity. This pattern is consistent with muscular shortening and the production of axial bends, although variability in the pattern indicates that other muscles may affect the mechanics of the epaxial muscles. The kinematic and motor patterns in snakes crawling against experimentally increased drag indicated that forces are produced largely by muscles that are active in the axial bend around each peg, rather than by distant muscles from which the forces might be transmitted by connective tissues. At each point of force exertion, the propulsive mechanism of terrestrial lateral undulation may be modeled as a type of cam-follower, in which continuous bending of the trunk around the peg produces translation of the snake.

  2. Effects of Stroke on Ipsilesional End-Effector Kinematics in a Multi-Step Activity of Daily Living

    Science.gov (United States)

    Gulde, Philipp; Hughes, Charmayne Mary Lee; Hermsdörfer, Joachim

    2017-01-01

    Background: Stroke frequently impairs activities of daily living (ADL) and deteriorates the function of the contra- as well as the ipsilesional limbs. In order to analyze alterations of higher motor control unaffected by paresis or sensory loss, the kinematics of ipsilesional upper limb movements in patients with stroke has previously been analyzed during prehensile movements and simple tool use actions. By contrast, motion recording of multi-step ADL is rare and patient-control comparisons for movement kinematics are largely lacking. Especially in clinical research, objective quantification of complex externally valid tasks can improve the assessment of neurological impairments. Methods: In this preliminary study we employed three-dimensional motion recording and applied kinematic analysis in a multi-step ADL (tea-making). The trials were examined with respect to errors and sub-action structure, durations, path lengths (PLs), peak velocities, relative activity (RA) and smoothness. In order to check for specific burdens the sub-actions of the task were extracted and compared. To examine the feasibility of the approach, we determined the behavioral and kinematic metrics of the (ipsilesional) unimanual performance of seven chronic stroke patients (64a ± 11a, 3 with right/4 with left brain damage (LBD), 2 with signs of apraxia, variable severity of paresis) and compared the results with data of 14 neurologically healthy age-matched control participants (70a ± 7a). Results: T-tests revealed that while the quantity and structure of sub-actions of the task were similar. The analysis of end-effector kinematics was able to detect clear group differences in the associated parameters. Specifically, trial duration (TD) was increased (Cohen’s d = 1.77); the RA (Cohen’s d = 1.72) and the parameters of peak velocities (Cohen’s d = 1.49/1.97) were decreased in the patient group. Analysis of the task’s sub-actions repeated measures analysis of variance (rmANOVA) revealed

  3. Optimizing Computation of Repairs from Active Integrity Constraints

    DEFF Research Database (Denmark)

    Cruz-Filipe, Luís

    2014-01-01

    Active integrity constraints (AICs) are a form of integrity constraints for databases that not only identify inconsistencies, but also suggest how these can be overcome. The semantics for AICs defines different types of repairs, but deciding whether an inconsistent database can be repaired...

  4. Upper extremity kinematics and muscle activation patterns in subjects with facioscapulohumeral dystrophy

    NARCIS (Netherlands)

    Bergsma, A.; Murgia, A.; Cup, E.H.C.; Verstegen, P.P.; Meijer, K.; Groot, I.J.M. de

    2014-01-01

    OBJECTIVE: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. DESIGN: Exploratory case-control study. SETTING: A movement laboratory. PARTICIPANTS: Subjects

  5. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects

  6. Upper Extremity Kinematics and Muscle Activation Patterns in Subjects With Facioscapulohumeral Dystrophy

    NARCIS (Netherlands)

    Bergsma, Arjen; Murgia, Alessio; Cup, Edith H.; Verstegen, Paul P.; Meijer, Kenneth; de Groot, Imelda J.

    2014-01-01

    Objective: To compare the kinematics and muscle activity of subjects with facioscapulohumeral dystrophy (FSHD) and healthy control subjects during the performance of standardized upper extremity tasks. Design: Exploratory case-control study. Setting: A movement laboratory. Participants: Subjects (N=

  7. Kinematic evidence for superbubbles in I Zw 18 constraints on the star formation history and chemical evolution

    CERN Document Server

    Martin, L

    1996-01-01

    We have combined measurements of the kinematics, morphology, and oxygen abundance of the ionized gas in \\IZw18, one of the most metal-poor galaxies known, to examine the star formation history and chemical mixing processes.

  8. Phonotactic Constraints Are Activated across Languages in Bilinguals

    Science.gov (United States)

    Freeman, Max R.; Blumenfeld, Henrike K.; Marian, Viorica

    2016-01-01

    During spoken language comprehension, auditory input activates a bilingual’s two languages in parallel based on phonological representations that are shared across languages. However, it is unclear whether bilinguals access phonotactic constraints from the non-target language during target language processing. For example, in Spanish, words with s+ consonant onsets cannot exist, and phonotactic constraints call for epenthesis (addition of a vowel, e.g., stable/estable). Native Spanish speakers may produce English words such as estudy (“study”) with epenthesis, suggesting that these bilinguals apply Spanish phonotactic constraints when speaking English. The present study is the first to examine whether bilinguals access Spanish phonotactic constraints during English comprehension. In an English cross-modal priming lexical decision task, Spanish–English bilinguals and English monolinguals heard English cognate and non-cognate primes containing s+ consonant onsets or controls without s+ onsets, followed by a lexical decision on visual targets with the /e/ phonotactic constraint or controls without /e/. Results revealed that bilinguals were faster to respond to /es/ non-word targets preceded by s+ cognate primes and /es/ and /e/ non-word targets preceded by s+ non-cognate primes, confirming that English primes containing s+ onsets activated Spanish phonotactic constraints. These findings are discussed within current accounts of parallel activation of two languages during bilingual spoken language comprehension, which may be expanded to include activation of phonotactic constraints from the irrelevant language. PMID:27242615

  9. The use of smartphones to teach kinematics: an inexpensive activity

    Science.gov (United States)

    André Testoni, Leonardo; Brockington, Guilherme

    2016-11-01

    This frontline seeks to reinterpret a classic kinematic experiment that aims to mark the position and temporal instants of a fictional mobile object in a uniform motion, creating a table based on position × time and a linear graphic format. Generally, this approach requires sophisticated experimental apparatus (such as air mattresses or rails) that may limit its ability to be reproduced due to cost and thus jeopardising the exercise. Therefore, we suggest that this experiment be performed with real mobile objects to be able to observe the difficulty in controlling the kinematic variables that produce a ‘perfectly’ uniform movement. This object can be the student, playing a uniform motion walking on a trajectory with markings of 5 m in 5 m amounting to a total displacement of 30 m. Additionally, acceleration data is collected during the journey via a smartphone accelerometer, allowing for more in-depth discussions of these essential concepts for the study of bodies in motion.

  10. The SAMI Galaxy Survey: Unveiling the nature of kinematically offset active galactic nuclei

    CERN Document Server

    Allen, J T; Scott, N; Fogarty, L M R; Ho, I -T; Medling, A M; Leslie, S K; Bland-Hawthorn, J; Bryant, J J; Croom, S M; Goodwin, M; Green, A W; Konstantopoulos, I S; Lawrence, J S; Owers, M S; Richards, S N; Sharp, R

    2015-01-01

    We have observed two kinematically offset active galactic nuclei (AGN), whose ionised gas is at a different line-of-sight velocity to their host galaxies, with the SAMI integral field spectrograph (IFS). One of the galaxies shows gas kinematics very different to the stellar kinematics, indicating a recent merger or accretion event. We demonstrate that the star formation associated with this event was triggered within the last 100 Myr. The other galaxy shows simple disc rotation in both gas and stellar kinematics, aligned with each other, but in the central region has signatures of an outflow driven by the AGN. Other than the outflow, neither galaxy shows any discontinuity in the ionised gas kinematics at the galaxy's centre. We conclude that in these two cases there is no direct evidence of the AGN being in a supermassive black hole binary system. Our study demonstrates that selecting kinematically offset AGN from single-fibre spectroscopy provides, by definition, samples of kinematically peculiar objects, bu...

  11. Kinematic Analysis of Four-Link Suspension of Steering Wheel by Means of Equation Sets of Geometrical Constraints with Various Structure

    Science.gov (United States)

    Kowalski, M. S.

    2016-09-01

    In research of the kinematic and dynamic properties of complex mechanical set-ups, results of numerical experiments are used. It is required to minimize the calculation time of various problems in the domain. For the multi-link suspension of the steered wheel, sets of the equations of the geometrical constraints were presented in two structurally different forms, scalar and vector. The vector set consists of the transcendental equations. Their solution was possible after previous expanding the trigonometric functions into power series. Because of the finite amount of the computer memory for the algorithm solving the vector form, it was possible to obtain solutions consisting of three terms. The number of terms in power series of equations' solutions determines the magnitudes of increments of input parameters (degrees of freedom). In this paper it is demonstrated, that fulfilling of this demand is possible by the change of the geometrical constraint's structure of the multi-link wheel suspension system.

  12. Dynamic active constraints for hyper-redundant flexible robots.

    Science.gov (United States)

    Kwok, Ka-Wai; Mylonas, George P; Sun, Loi Wah; Lerotic, Mirna; Clark, James; Athanasiou, Thanos; Darzi, Ara; Yang, Guang-Zhong

    2009-01-01

    In robot-assisted procedures, the surgeon's ability can be enhanced by navigation guidance through the use of virtual fixtures or active constraints. This paper presents a real-time modeling scheme for dynamic active constraints with fast and simple mesh adaptation under cardiac deformation and changes in anatomic structure. A smooth tubular pathway is constructed which provides assistance for a flexible hyper-redundant robot to circumnavigate the heart with the aim of undertaking bilateral pulmonary vein isolation as part of a modified maze procedure for the treatment of debilitating arrhythmia and atrial fibrillation. In contrast to existing approaches, the method incorporates detailed geometrical constraints with explicit manipulation margins of the forbidden region for an entire articulated surgical instrument, rather than just the end-effector itself. Detailed experimental validation is conducted to demonstrate the speed and accuracy of the instrument navigation with and without the use of the proposed dynamic constraints.

  13. Kinematic active region formation in a three-dimensional solar dynamo model

    CERN Document Server

    Yeates, A R

    2013-01-01

    We propose a phenomenological technique for modelling the emergence of active regions within a three-dimensional, kinematic dynamo framework. By imposing localised velocity perturbations, we create emergent flux-tubes out of toroidal magnetic field at the base of the convection zone, leading to the eruption of active regions at the solar surface. The velocity perturbations are calibrated to reproduce observed active region properties (including the size and flux of active regions, and the distribution of tilt angle with latitude), resulting in a more consistent treatment of flux-tube emergence in kinematic dynamo models than artificial flux deposition. We demonstrate how this technique can be used to assimilate observations and drive a kinematic 3D model, and use it to study the characteristics of active region emergence and decay as a source of poloidal field. We find that the poloidal components are strongest not at the solar surface, but in the middle convection zone, in contrast with the common assumption...

  14. Paleomagnetic, structural, and stratigraphic constraints on transverse fault kinematics during basin inversion: The Pamplona Fault (Pyrenees, north Spain)

    Science.gov (United States)

    LarrasoañA, Juan Cruz; ParéS, Josep MaríA.; MilláN, HéCtor; Del Valle, JoaquíN.; Pueyo, Emilio Luis

    2003-12-01

    The Pamplona Fault in the Pyrenees is a major transverse structure that has been classically interpreted as a strike-slip fault. However, lack of consensus concerning the sense of movement casts doubt on its actual kinematics and, as a consequence, its role in the Cenozoic evolution of the Pyrenees remains controversial. In order to assess its kinematics, we have conducted a paleomagnetic, structural, and stratigraphic study focused on the Mesozoic and Tertiary sedimentary rocks that outcrop around the southern segment of the fault. Restoration of balanced cross sections allows us to examine the present-day spatial relationship of the sedimentary sequences on both sides of the fault and to reconstruct the geometry of the extensional basins formed during Mesozoic rifting episodes in the Bay of Biscay and Pyrenean domains. Paleomagnetic results indicate that no significant tectonic rotations occurred around the fault during Tertiary inversion of the Pyrenees. The lack of tectonic rotations and revaluation of previous hypotheses argues against a strike-slip movement of the fault. We propose a new model in which the Pamplona Fault is treated as a large-scale "hanging wall drop" fault whose kinematics was determined by variations in the geometry and thickness of Mesozoic sequences on both sides of the fault. These variations influenced the geometry of the thrust sheet developed during Tertiary compression. We are unaware of any other transverse fault that has been interpreted in this fashion; thus the Pamplona Fault serves as a case study for the evolution of transverse faults involved in basin inversion processes.

  15. Observational constraints on the kinematics and the fate of the Universe through linearly varying deceleration parameter laws

    CERN Document Server

    Akarsu, Ozgur; Kumar, Suresh; Xu, Lixin

    2014-01-01

    We study linearly varying deceleration parameter in terms of cosmic time t (LVDPt) with the companion linearly varying deceleration parameter in terms of cosmic redshift z (LVDPz) and in terms of cosmic scale factor a (LVDPa). We investigate in detail the kinematics and the fate of the Universe by confronting the three LVDP laws with the latest observational data from H(z) compilation (25 data points) and SN Ia Union2.1 compilation (580 data points). The study reveals that the LVDPt law is superior than LVDPz and LVDPa laws in many aspects. In particular, the goodness of fit to the observational data is found to be the best for the LVDPt law. The kinematics and dynamics (assuming general relativity) of the Universe is further studied by considering the LVDPt law in comparison with the standard LCDM model. It is found that these two models are observationally indistinguishable but the LVDPt fits the data slightly better than the LCDM model. These two models exhibit a very similar behavior for a long passage of...

  16. Kinematics and Chemistry of Stars Along the Sagittarius Trailing Tidal Tail and Constraints on the Milky Way Mass Distribution

    CERN Document Server

    Carlin, Jeffrey L; Casetti-Dinescu, Dana I; Law, David R; Girard, Terrence M; Patterson, Richard J

    2011-01-01

    We present three-dimensional kinematics of Sagittarius (Sgr) trailing tidal debris in six fields located 70-130 degrees along the stream from the Sgr dwarf galaxy core. The data are from our proper-motion (PM) survey of Kapteyn's Selected Areas, in which we have measured accurate PMs to faint magnitudes in 40x40 arcmin fields evenly spaced across the sky. The radial velocity (RV) signature of Sgr has been identified among our follow-up spectroscopic data in four of the six fields and combined with mean PMs of spectroscopically-confirmed members to derive space motions of Sgr debris based on 15-64 confirmed stream members per field. These kinematics are compared to predictions of the Law & Majewski (2010) model of Sgr disruption; we find reasonable agreement with model predictions in RVs and PMs along Galactic latitude. However, an upward adjustment of the Local Standard of Rest velocity Theta_LSR from its standard 220 km/s to at least $232\\pm14$ km/s (and possibly as high as $264\\pm23$ km/s) is necessary ...

  17. Muscle activity and kinematics of forefoot and rearfoot strike runners

    Directory of Open Access Journals (Sweden)

    A.N. Ahn

    2014-06-01

    Conclusion: This earlier and longer relative activation of the plantarflexors likely enhances the capacity for the passive structures of the foot and ankle to store elastic energy, and may also enhance the performance of the active muscle by increasing the storage of elastic strain energy in the cross-bridges and activated titin.

  18. Constraints on leisure time physical activity at a public university

    Directory of Open Access Journals (Sweden)

    Kubilay Öcal

    2014-09-01

    Full Text Available This study focuses on understanding constraints on leisure time physical activity (LTPA on a university campus. The survey study was conducted with public university students (n=563 living in dormitories. The 38-item, 8-dimension Leisure Time Physical Activity Constraints (LTPA-C Scale was used to investigate factors limiting LTPA. Age, gender, working status (i.e. part-time, non-working, program type (i.e. morning education, evening education, relationship status (i.e. in a relationship, not in a relationship, monthly expenses and body mass index (BMI category (i.e. underweight, normal weight, overweight, obese are key variables believed to affect LTPA-C. An initial confirmatory factor analysis was conducted to validate the structure of the scale, and frequency analysis, Pearson’s Correlation and t-tests were conducted to analyze the survey responses. Results showed the hierarchy of constraints for males (from high to low to be as follows: society, income, time, facility, willpower, skill perception, family, body perception. The hierarchy was nearly identical for females, except ‘willpower’ was found to be a greater constraint than ‘facility’; moreover, the differences in the rates at which males and females perceived ‘facility’ and ‘willpower’ to be constraints were statistically significant.The study findings indicate that by taking steps to improve the infrastructure of university campus facilities and organize group activities, university management can provide motivation and social support that can help to increase university student participation in LTPA.

  19. KINEMATICS AND CHEMISTRY OF STARS ALONG THE SAGITTARIUS TRAILING TIDAL TAIL AND CONSTRAINTS ON THE MILKY WAY MASS DISTRIBUTION

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, Jeffrey L.; Majewski, Steven R.; Patterson, Richard J. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Casetti-Dinescu, Dana I.; Girard, Terrence M. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Law, David R., E-mail: jc4qn@mail.astro.virginia.edu, E-mail: carlij@rpi.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2012-01-01

    We present three-dimensional (3D) kinematics of Sagittarius (Sgr) trailing tidal debris in six fields located 70 Degree-Sign -130 Degree-Sign along the stream from the Sgr dwarf galaxy core. The data are from our proper-motion (PM) survey of Kapteyn's Selected Areas, in which we have measured accurate PMs to faint magnitudes in {approx}40' Multiplication-Sign 40' fields evenly spaced across the sky. The radial velocity (RV) signature of Sgr has been identified among our follow-up spectroscopic data in four of the six fields and combined with mean PMs of spectroscopically confirmed members to derive space motions of Sgr debris based on {approx}15-64 confirmed stream members per field. These kinematics are compared to predictions of the Law and Majewski model of Sgr disruption; we find reasonable agreement with model predictions in RVs and PMs along Galactic latitude. However, an upward adjustment of the local standard of rest velocity ({Theta}{sub LSR}) from its standard 220 km s{sup -1} to at least 232 {+-} 14 km s{sup -1} (and possibly as high as 264 {+-} 23 km s{sup -1}) is necessary to bring 3D model debris kinematics and our measurements into agreement. Satisfactory model fits that simultaneously reproduce known position, distance, and RV trends of the Sgr tidal streams, while significantly increasing {Theta}{sub LSR}, could only be achieved by increasing the Galactic bulge and disk mass while leaving the dark matter halo fixed to the best-fit values from Law and Majewski. We derive low-resolution spectroscopic abundances along this stretch of the Sgr stream and find a constant [Fe/H] {approx} -1.15 (with {approx}0.5 dex scatter in each field-typical for dwarf galaxy populations) among the four fields with reliable measurements. A constant metallicity suggests that debris along the {approx}60 Degree-Sign span of this study was all stripped from Sgr on the same orbital passage.

  20. EFFECT OF KAYAK ERGOMETER ELASTIC TENSION ON UPPER LIMB EMG ACTIVITY AND 3D KINEMATICS

    Directory of Open Access Journals (Sweden)

    Neil Fleming

    2012-09-01

    Full Text Available Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10 performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p < 0.001, no significant differences were detected in assessed force variables during the stroke cycle. In contrast, increasing tension induced significantly higher Anterior Deltoid (AD activity in the latter stages (70 to 90% of the cycle (p < 0.05. No significant differences were observed across tension levels for Triceps Brachii or Latissimus Dorsi. Kinematic analysis revealed that overhead arm movements accounted for 39 ± 16% of the cycle. Elbow angle at stroke cycle onset was 144 ± 10°; maximal elbow angle (151 ± 7° occurred at 78 ± 10% into the cycle. All kinematic markers moved to a more anterior position as tension increased. No significant change in wrist marker elevation was observed, while elbow and shoulder marker elevations significantly increased across tension levels (p < 0.05. In conclusion, data suggested that kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces

  1. Kinematics of hip, knee, ankle of the young and elderly Chinese people during kneeling activity*

    OpenAIRE

    Zhou, Hai; Wang, Dong-Mei; Liu, Tao-ran; Zeng, Xiang-sen; Wang, Cheng-tao

    2012-01-01

    Objective: The purpose of this study was to measure the kinematics of the lower limbs of Chinese people during normal kneeling activity, as such data could be valuable in designing joint prosthesis and arthroplasty that meet the needs of Chinese citizens’ daily activities. Methods: Thirty young and twenty elderly Chinese participants with no personal history of joint diseases were recruited, and matched by age (average age: 23.8 years for the young group, 60.8 years for the elderly group). Ea...

  2. New constraints on the active tectonic deformation of the Aegean

    Science.gov (United States)

    Nyst, M.; Thatcher, W.

    2004-01-01

    Site velocities from six separate Global Positioning System (GPS) networks comprising 374 stations have been referred to a single common Eurasia-fixed reference frame to map the velocity distribution over the entire Aegean. We use the GPS velocity field to identify deforming regions, rigid elements, and potential microplate boundaries, and build upon previous work by others to initially specify rigid elements in central Greece, the South Aegean, Anatolia, and the Sea of Marmara. We apply an iterative approach, tentatively defining microplate boundaries, determining best fit rigid rotations, examining misfit patterns, and revising the boundaries to achieve a better match between model and data. Short-term seismic cycle effects are minor contaminants of the data that we remove when necessary to isolate the long-term kinematics. We find that present day Aegean deformation is due to the relative motions of four microplates and straining in several isolated zones internal to them. The RMS misfit of model to data is about 2-sigma, very good when compared to the typical match between coseismic fault models and GPS data. The simplicity of the microplate description of the deformation and its good fit to the GPS data are surprising and were not anticipated by previous work, which had suggested either many rigid elements or broad deforming zones that comprise much of the Aegean region. The isolated deforming zones are also unexpected and cannot be explained by the kinematics of the microplate motions. Strain rates within internally deforming zones are extensional and range from 30 to 50 nanostrain/year (nstrain/year, 10-9/year), 1 to 2 orders of magnitude lower than rates observed across the major microplate boundaries. Lower strain rates may exist elsewhere withi the microplates but are only resolved in Anatolia, where extension of 13 ?? 4 nstrain/ year is required by the data. Our results suggest that despite the detailed complexity of active continental deformation

  3. Dimensionality Reduction in Controlling Articulated Snake Robot for Endoscopy Under Dynamic Active Constraints

    Science.gov (United States)

    Kwok, Ka-Wai; Tsoi, Kuen Hung; Vitiello, Valentina; Clark, James; Chow, Gary C. T.; Luk, Wayne; Yang, Guang-Zhong

    2014-01-01

    This paper presents a real-time control framework for a snake robot with hyper-kinematic redundancy under dynamic active constraints for minimally invasive surgery. A proximity query (PQ) formulation is proposed to compute the deviation of the robot motion from predefined anatomical constraints. The proposed method is generic and can be applied to any snake robot represented as a set of control vertices. The proposed PQ formulation is implemented on a graphic processing unit, allowing for fast updates over 1 kHz. We also demonstrate that the robot joint space can be characterized into lower dimensional space for smooth articulation. A novel motion parameterization scheme in polar coordinates is proposed to describe the transition of motion, thus allowing for direct manual control of the robot using standard interface devices with limited degrees of freedom. Under the proposed framework, the correct alignment between the visual and motor axes is ensured, and haptic guidance is provided to prevent excessive force applied to the tissue by the robot body. A resistance force is further incorporated to enhance smooth pursuit movement matched to the dynamic response and actuation limit of the robot. To demonstrate the practical value of the proposed platform with enhanced ergonomic control, detailed quantitative performance evaluation was conducted on a group of subjects performing simulated intraluminal and intracavity endoscopic tasks. PMID:24741371

  4. Physical activity participation and constraints among athletic training students.

    Science.gov (United States)

    Stanek, Justin; Rogers, Katherine; Anderson, Jordan

    2015-02-01

    Researchers have examined the physical activity (PA) habits of certified athletic trainers; however, none have looked specifically at athletic training students. To assess PA participation and constraints to participation among athletic training students. Cross-sectional study. Entry-level athletic training education programs (undergraduate and graduate) across the United States. Participants were 1125 entry-level athletic training students. Self-reported PA participation, including a calculated PA index based on a typical week. Leisure constraints and demographic data were also collected. Only 22.8% (252/1105) of athletic training students were meeting the American College of Sports Medicine recommendations for PA through moderate-intensity cardiorespiratory exercise. Although 52.3% (580/1105) were meeting the recommendations through vigorous-intensity cardiorespiratory exercise, 60.5% (681/1125) were meeting the recommendations based on the combined total of moderate or vigorous cardiorespiratory exercise. In addition, 57.2% (643/1125) of respondents met the recommendations for resistance exercise. Exercise habits of athletic training students appear to be better than the national average and similar to those of practicing athletic trainers. Students reported structural constraints such as lack of time due to work or studies as the most significant barrier to exercise participation. Athletic training students experienced similar constraints to PA participation as practicing athletic trainers, and these constraints appeared to influence their exercise participation during their entry-level education. Athletic training students may benefit from a greater emphasis on work-life balance during their entry-level education to promote better health and fitness habits.

  5. First spectro-interferometric survey of Be stars I. Observations and constraints on the disks geometry and kinematics

    CERN Document Server

    Meilland, Anthony; Kanaan, Samer; Stee, Philippe; Petrov, Romain

    2011-01-01

    Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk responsible for the observed infrared-excess and emission lines. The phenomena involved in the disk formation still remain highly debated. Aims. To progress in the understanding of the physical process or processes responsible for the mass-ejection and test the hypothesis that they depends on the stellar parameters, we initiate a survey on the circumstellar environment of the brightest Be stars. Methods. To achieve this goal, we used spectro-interferometry, the only technique combining high spectral (R=12000) and high spatial (\\thetamin=4mas) resolutions. Observations were carried out at Paranal observatory with the VLTI/AMBER instrument. We concentrate our observations on the Br{\\gamma} emission line to be able to study the kinematics within the circumstellar disk. Our sample is composed of eight bright classical Be stars : \\alph Col, \\kappa CMa, \\omega Car, p Car, \\delta Cen, \\mu Cen, \\alpha Ara, and o Aqr. R...

  6. Paleomagnetism of the Stanislaus Group, CA reveals revised stratigraphy, Walker Lane kinematics, and radio-isotopic constraints on C5 magnetic subchrons

    Science.gov (United States)

    Pluhar, C. J.; Wright, T. J.; Fischer, C. P.; Busby, C. J.

    2007-12-01

    Paleomagnetic study of the c.a. 9.2-10.3 Ma Stanislaus Group of intercalated latite (trachyandesite) lavas, ignimbrites and accessory sediments at three localities in Mono county California reveals: 1) a detailed, revised stratigraphy for the Stanislaus group, 2) kinematic constraints on the part of the Walker Lane since Stanislaus group emplacement, and 3) two age-constrained magnetic subchrons during chron C5N recorded by latites that had previously only been identified in seafloor magnetic anomalies. The revised stratigraphy results from detailed magnetostratigraphy combined with previous 40Ar/39Ar geochronologic constraints and stratigraphic studies. We find the lowermost unit, Table Mountain Latite, to consist of 23 or more individual lava flows falling into 5 magnetic (mostly normal) polarity zones, indicating that these rocks span at least 40,000 years of geologic time, based on the expected duration of magnetic reversals. Overlying Table Mountain Latite is the reversed-polarity Tollhouse Flat member of the Eureka Valley Tuff as described by previous authors. In the Sweetwater Roadless Area, thought to be proximal to the Stanislaus eruptive center, latite lava of both normal and reversed polarity are emplaced ontop of the Tollhouse Flat Member. Normal-polarity By Day member and normal-polarity Upper Member lie at very top of entire sequence. We find no field evidence for the normal polarity Dardanelle Formation latite flow at the top of the Group as had been previously reported by other workers. Instead, the Dardanelle formation member likely corresponds to the latite lava(s) between the By Day and Tollhouse Flat Eureka Valley Tuff. Based on previous 40Ar/39Ar dating, the two reversed zones within our magnetostratigraphy correspond to two of the proposed reversed subchrons/excursions during chron C5N. Direct dating of these reversed units may lead to future improvements to the magnetic polarity timescale for C5N. Our paleomagnetic results from three study

  7. Kinematic constraints on buckling a lithospheric-scale orocline along the northern margin of Gondwana: A geologic synthesis

    Science.gov (United States)

    Weil, A. Brandon; Gutiérrez-Alonso, G.; Johnston, S. T.; Pastor-Galán, D.

    2013-01-01

    The Paleozoic Variscan orogeny was a large-scale collisional event involving amalgamation of multiple continents and micro-continents. Existing data, suggests oroclinal buckling of an originally near-linear convergent margin during the last stages of Variscan deformation in the late Paleozoic. Closure of the Rheic Ocean resulted in E-W shortening (present-day coordinates) in the Carboniferous, producing a near linear N-S trending, east-verging belt. Subsequent N-S shortening near the Carb-Permian boundary resulted in oroclinal buckling. This late-stage orogenic event remains an enigmatic part of final Pangea amalgamation. The present-day arc curvature of the Variscan has inspired many tectonic models, with little agreement between them. While there is general consensus that two separate phases of deformation occurred, various models consider that curvature was caused by: dextral transpression around a Gondwana indentor; strike-slip wrench tectonics; or a change in tectonic transport direction due to changing stress fields. More recent models explain the curvature as an orocline, with potentially two opposite-facing bends, caused by secondary rotations. Deciphering the kinematic history of curved orogens is difficult, and requires establishment of two deformation phases: an initial compressive phase that forms a relatively linear belt, and a second phase that causes vertical-axis rotation of the orogenic limbs. Historically the most robust technique to accurately quantify vertical axis-rotation in curved orogens is paleomagnetic analysis, but recently other types of data, including fracture, geochemical, petrologic, paleo-current and calcite twin data, have been used to corroborate secondary buckling. A review of existing and new Variscan data from Iberia is presented that argues for secondary buckling of an originally linear orogenic system. Together, these data constrain oroclinal buckling of the Cantabrian Orocline to have occurred in about 10 Ma during the

  8. CONSTRAINTS ON THE MAGELLANIC CLOUDS' INTERACTION FROM THE DISTRIBUTION OF OB STARS AND THE KINEMATICS OF GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Casetti-Dinescu, Dana I.; Girard, Terrence M.; Van Altena, William F. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Vieira, Katherine, E-mail: dana.casetti@yale.edu, E-mail: terry.girard@yale.edu, E-mail: william.vanaltena@yale.edu, E-mail: kvieira@cida.ve [Centro de Investigaciones de Astronomia, Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of)

    2012-07-10

    Young, OB-type candidates are identified in a {approx}7900 deg{sup 2} region encompassing the Large and Small Magellanic Clouds (LMC/SMC) periphery, the Bridge, part of the Magellanic Stream (MS), and Leading Arm (LA). Selection is based on UV, optical, and IR photometry from existing large-area surveys and proper motions from the Southern Proper Motion 4 (SPM4) catalog. The spatial distribution of these young star candidates shows (1) a well-populated SMC wing which continues westward with two branches partially surrounding the SMC, (2) a rather narrow path from the SMC wing eastward toward the LMC which is offset by 1 Degree-Sign -2 Degree-Sign from the high-density H I ridge in the Bridge, (3) a well-populated periphery of the LMC dominated by clumps of stars at the ends of the LMC bar, and (4) a few scattered candidates in the MS and two overdensities in the LA regions above and below the Galactic plane. Additionally, a proper-motion analysis is made of a radial-velocity-selected sample of red giants and supergiants in the LMC, previously shown to be a kinematically and chemically distinct subgroup, most likely captured from the SMC. SPM4 proper motions of these stars also indicate they are distinct from the LMC population. The observational results presented here, combined with the known orbits of the Clouds and other aspects of the LMC morphology, suggest an off-center, moderate to highly inclined collision between the SMC and the LMC's disk that took place between 100 and 200 Myr ago.

  9. GPS Rapid Static and Kinematic Positioning Based on GPS Active Network

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper presents a data processing strategy for GPS kinematic positioning by using a GPS active network to model the GPS errors in double difference observable.Firstly,the double difference residuals are estimated between the reference stations in the active network.Then the errors at a user station are predicted as the network corrections to user measurements,based on the location of the user.Finally conventional kinematic positioning algorithms can be applied to determine the position of the user station.As an example,continuous 24-hour GPS data in March 2001 has been processed by this method.It clearly demonstrates that,after applying these corrections to a user within the network,both the success rate for ambiguity resolution and the positioning accuracy have been significantly improved.

  10. Fundamental Activity Constraints Lead to Specific Interpretations of the Connectome

    Science.gov (United States)

    van Albada, Sacha J.; Diesmann, Markus; Helias, Moritz

    2017-01-01

    The continuous integration of experimental data into coherent models of the brain is an increasing challenge of modern neuroscience. Such models provide a bridge between structure and activity, and identify the mechanisms giving rise to experimental observations. Nevertheless, structurally realistic network models of spiking neurons are necessarily underconstrained even if experimental data on brain connectivity are incorporated to the best of our knowledge. Guided by physiological observations, any model must therefore explore the parameter ranges within the uncertainty of the data. Based on simulation results alone, however, the mechanisms underlying stable and physiologically realistic activity often remain obscure. We here employ a mean-field reduction of the dynamics, which allows us to include activity constraints into the process of model construction. We shape the phase space of a multi-scale network model of the vision-related areas of macaque cortex by systematically refining its connectivity. Fundamental constraints on the activity, i.e., prohibiting quiescence and requiring global stability, prove sufficient to obtain realistic layer- and area-specific activity. Only small adaptations of the structure are required, showing that the network operates close to an instability. The procedure identifies components of the network critical to its collective dynamics and creates hypotheses for structural data and future experiments. The method can be applied to networks involving any neuron model with a known gain function. PMID:28146554

  11. A word-order constraint on phonological activation.

    Science.gov (United States)

    Janssen, Niels; Alario, F-Xavier; Caramazza, Alfonso

    2008-03-01

    Word-order rules impose major constraints on linguistic behavior. For example, adjectives appear before nouns in English, and after nouns in French. This means that constraints on word order must be language-specific properties upheld on-line by the language system. Despite the importance of these rules, little is known about how they operate. We report an influence of word order on the activation of phonological representations. Participants were presented with colored objects and asked to name either the colors or the objects; the phonological similarity between the object and color names was manipulated. French speakers showed a phonological congruency effect in color naming, but not in object naming. English participants yielded the opposite pattern: a phonological effect in object naming, but not in color naming. Differences in the typical order of nouns and adjectives in French and English provide a plausible account for this cross-linguistic contrast. More generally, these results provide direct evidence for the operation of word-order constraints during language production.

  12. Implicit Active Constraints for Robot-Assisted Arthroscopy.

    Science.gov (United States)

    Lopez, Edoardo; Kwok, Ka-Wai; Payne, Christopher J; Giataganas, Petros; Yang, Guang-Zhong

    2013-05-10

    This paper presents an Implicit Active Constraints control framework for robot-assisted minimally invasive surgery. It extends on current frameworks by prescribing the external constraints implicitly from the operator motion, forgoing the need for pre-operative imaging; the constraints are defined in situ so as to avoid the use of invasive fiducial markers. A hands-on cooperatively-controlled robotic platform, comprising of a surgical instrument and a compliant manipulator, has been designed for an arthroscopic procedure. The surgical platform is capable of constraining the pose of the instrument so as to ensure it passes through the incision point and does not cause trauma to the surrounding tissue. A flexible arthroscopic instrument is designed and its use is investigated to enlarge reachable and dexterous workspace, increasing the accessibility to the target anatomy. The behaviour of the flexible instrument is analysed. A detailed performance analysis is conducted on a group of subjects for validating the control framework, simulating a minimally invasive arthroscopic procedure. Results demonstrate a statistically significant enhancement in the control ergonomics as well as the accuracy and safety of the procedure.

  13. Kinematic and Electromyographic Activity Changes during Back Squat with Submaximal and Maximal Loading

    Directory of Open Access Journals (Sweden)

    Hasan U. Yavuz

    2017-01-01

    Full Text Available The aim of this study was to investigate the possible kinematic and muscular activity changes with maximal loading during squat maneuver. Fourteen healthy male individuals, who were experienced at performing squats, participated in this study. Each subject performed squats with 80%, 90%, and 100% of the previously established 1 repetition maximum (1RM. Electromyographic (EMG activities were measured for the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, and erector spinae by using an 8-channel dual-mode portable EMG and physiological signal data acquisition system (Myomonitor IV, Delsys Inc., Boston, MA, USA. Kinematical data were analyzed by using saSuite 2D kinematical analysis program. Data were analyzed with repeated measures analysis of variance (p<0.05. Overall muscle activities increased with increasing loads, but significant increases were seen only for vastus medialis and gluteus maximus during 90% and 100% of 1RM compared to 80% while there was no significant difference between 90% and 100% for any muscle. The movement pattern in the hip joint changed with an increase in forward lean during maximal loading. Results may suggest that maximal loading during squat may not be necessary for focusing on knee extensor improvement and may increase the lumbar injury risk.

  14. Shaping tissues by balancing active forces and geometric constraints

    Science.gov (United States)

    Foolen, Jasper; Yamashita, Tadahiro; Kollmannsberger, Philip

    2016-02-01

    The self-organization of cells into complex tissues during growth and regeneration is a combination of physical-mechanical events and biochemical signal processing. Cells actively generate forces at all stages in this process, and according to the laws of mechanics, these forces result in stress fields defined by the geometric boundary conditions of the cell and tissue. The unique ability of cells to translate such force patterns into biochemical information and vice versa sets biological tissues apart from any other material. In this topical review, we summarize the current knowledge and open questions of how forces and geometry act together on scales from the single cell to tissues and organisms, and how their interaction determines biological shape and structure. Starting with a planar surface as the simplest type of geometric constraint, we review literature on how forces during cell spreading and adhesion together with geometric constraints impact cell shape, stress patterns, and the resulting biological response. We then move on to include cell-cell interactions and the role of forces in monolayers and in collective cell migration, and introduce curvature at the transition from flat cell sheets to three-dimensional (3D) tissues. Fibrous 3D environments, as cells experience them in the body, introduce new mechanical boundary conditions and change cell behaviour compared to flat surfaces. Starting from early work on force transmission and collagen remodelling, we discuss recent discoveries on the interaction with geometric constraints and the resulting structure formation and network organization in 3D. Recent literature on two physiological scenarios—embryonic development and bone—is reviewed to demonstrate the role of the force-geometry balance in living organisms. Furthermore, the role of mechanics in pathological scenarios such as cancer is discussed. We conclude by highlighting common physical principles guiding cell mechanics, tissue patterning and

  15. The perception and constraints towards recreational activity among female students

    Directory of Open Access Journals (Sweden)

    Azlan Ahmad Kamal

    2010-12-01

    Full Text Available More often than not, male students are seen to be more active in recreation activity than female students. To investigate this matter, a study was done on the female recreational activity participation. This study investigated the perception and constraints towards recreation activity among female students in a university in Malaysia. This study used a questionnaire regarding the recreation activity to collect the findings. Sixty respondents have been selected randomly as the subject for this study. All the information that is obtained from the questionnaire has been collected and analyzed using SPSS. It was found recreation is most often perceived as ‘extreme sports’ by female students. Moreover, most of the female students perceived themselves as participating regularly in recreational activity. The reasons for not participating in recreational activity are of lack of time, low energy level, lack of participants, lack of facilities and money. It was also found female students prefer outdoor activities such as camping, abseiling and wall climbing. Future studies should compare the perception of male and female students’ on recreational activity.

  16. Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use.

    Directory of Open Access Journals (Sweden)

    Hoi-Chi Woo

    Full Text Available Certain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public's concern whether hand activities while using smartphones can lead to median nerve problems.The aims of this study were to 1 develop kinematic graphs and 2 investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities.Dominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1 thumb opposition with the wrist in neutral position, 2 thumb opposition with the wrist in ulnar deviation and 3 pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1 cross-sectional area (CSA, 2 flattening ratio (FR, 3 rotational displacement (RD and 4 translational displacement (TD of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1 two successive time points during a single hand activity and 2 different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities.Performing different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during different hand activities were complex

  17. New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence

    Science.gov (United States)

    Gizis, John E.; Monet, David G.; Reid, I. Neill; Kirkpatrick, J. Davy; Liebert, James; Williams, Rik J.

    2000-08-01

    We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with Ksmass function that is smooth across the stellar/substellar limit. We show the observed frequency of Hα emission peaks at ~100% for M7 dwarfs and then decreases for cooler dwarfs. In absolute terms, however, as measured by the ratio of Hα to bolometric luminosity, none of the ultracool M dwarfs can be considered very active compared to earlier M dwarfs, and we show that the decrease that begins at spectral type M6 continues to the latest L dwarfs. We find that flaring is common among the coolest M dwarfs and estimate the frequency of flares at 7% or higher. We show that the kinematics of relatively active (EW>6 Å) ultracool M dwarfs are consistent with an ordinary old disk stellar population, while the kinematics of inactive ultracool M dwarfs are more typical of a 0.5 Gyr old population. The early L dwarfs in the sample have kinematics consistent with old ages, suggesting that the hydrogen-burning limit is near spectral types L2-L4. We use the available data on M and L dwarfs to show that chromospheric activity drops with decreasing mass and temperature and that at a given (M8 or later) spectral type, the younger field (brown) dwarfs are less active than many of the older, more massive field stellar dwarfs. Thus, contrary to the well-known stellar age-activity relationship, low activity in field ultracool dwarfs can be an indication of comparative youth and substellar mass.

  18. Effects of thigh holster use on kinematics and kinetics of active duty police officers.

    Science.gov (United States)

    Larsen, Louise Bæk; Tranberg, Roy; Ramstrand, Nerrolyn

    2016-08-01

    Body armour, duty belts and belt mounted holsters are standard equipment used by the Swedish police and have been shown to affect performance of police specific tasks, to decrease mobility and to potentially influence back pain. This study aimed to investigate the effects on gait kinematics and kinetics associated with use of an alternate load carriage system incorporating a thigh holster. Kinematic, kinetic and temporospatial data were collected using three dimensional gait analysis. Walking tests were conducted with nineteen active duty police officers under three different load carriage conditions: a) body armour and duty belt, b) load bearing vest, body armour and thigh holster and c) no equipment (control). No significant differences between testing conditions were found for temporospatial parameters. Range of trunk rotation was reduced for both load carriage conditions compared to the control condition (p<0.017). Range of hip rotation was more similar to the control condition when wearing thigh holster rather than the belt mounted hip holster (p<0.017). Moments and powers for both left and right ankles were significantly greater for both of the load carriage conditions compared to the control condition (p<0.017). This study confirms that occupational loads carried by police have a significant effect on gait kinematics and kinetics. Although small differences were observed between the two load carriage conditions investigated in this study, results do not overwhelmingly support selection of one design over the other. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. The Industrial Robot Kinematics Calibration Based on the Position Constraint%基于位置约束的工业机器人运动学标定∗

    Institute of Scientific and Technical Information of China (English)

    熊杰; 杨东升; 王允森; 袁晓慧

    2016-01-01

    Given the standard DH method was limited to describe parallel joint, MDH method was adopted to establish the robot kinematics. Based on the end position constraint, a general method was proposed to es-tablish the linear equations for structure parameter identification. To solve the degradation problems in the coefficient matrix of the equations, starting from the Jacobian matrix of the kinematics, the reasons for the degradation was analyzed. It was the theoretical basis to select the structural parameters. The conversion be-tween robot base coordinate system and the measurement coordinate system was discussed and then a simple calibration method based on the cross-bar was designed without coordinate conversion. After the simulation conducted in matlab, MOTOMAN-MH6 robot was calibrated by this method. After calibration, the cross bar length error calculated under teaching readings reduced from 4mm to less than 1mm. The results show that the calibration method is effective.%鉴于标准DH方法在描述平行关节时存在问题,采用MDH方法建立机器人的运动学,提出基于末端位置约束关系建立线性方程组进行结构参数辨识的一般方法。针对方程组系数矩阵退化的问题,从运动学的雅可比矩阵入手,分析了退化的原因,为结构参数选择提供了理论依据。讨论了机器人基坐标系和测量坐标系转换的问题,设计了一种无需坐标系转换的基于十字型杆件的简易标定方法。基于matlab进行仿真后,采用该方法标定MOTOMAN-MH6机器人,标定后,按照示教器读数计算的十字型杆件长度误差从4 mm降低到1 mm以内,说明该方法是有效的。

  20. New Neighbors from 2MASS Activity and Kinematics at the Bottom of the Main Sequence

    CERN Document Server

    Gizis, J E; Reid, I N; Kirkpatrick, J D; Liebert, J; Williams, R J; Gizis, John E.; Monet, David G.; Liebert, James; Williams, Rik J.

    2000-01-01

    We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with K_s6 Angstroms) ultracool M dwarfs are consistent with an ordinary old disk stellar population, while the kinematics of inactive ultracool M dwarfs are more typical of a 0.5 Gyr old population. The early L dwarfs in the sample have kinematics consistent with old ages, suggesting that the hydrogen burning limit is near spectral types L2-L4. We use the available data on M and L dwarfs to show that chromospheric activity drops with decreasing mass and temperature, and that at a given (M8 or later) spectral type, the younger field (brown) dwarfs are less active than many of the older, more massive field stellar dwarfs. Thus, contrary to the well-known stellar age-activity relationship, low activity in field ultracool dwarfs can be an indication of comparative youth and substellar mass.

  1. Using activity-based costing and theory of constraints to guide continuous improvement in managed care.

    Science.gov (United States)

    Roybal, H; Baxendale, S J; Gupta, M

    1999-01-01

    Activity-based costing and the theory of constraints have been applied successfully in many manufacturing organizations. Recently, those concepts have been applied in service organizations. This article describes the application of activity-based costing and the theory of constraints in a managed care mental health and substance abuse organization. One of the unique aspects of this particular application was the integration of activity-based costing and the theory of constraints to guide process improvement efforts. This article describes the activity-based costing model and the application of the theory of constraint's focusing steps with an emphasis on unused capacities of activities in the organization.

  2. Activity and Kinematics of White Dwarf-M Dwarf Binaries from the SUPERBLINK Proper Motion Survey

    Science.gov (United States)

    Skinner, Julie N.; Morgan, Dylan P.; West, Andrew A.; Lépine, Sébastien; Thorstensen, John R.

    2017-09-01

    We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV–optical–IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spectra and M dwarf template spectra to determine physical parameters. We use Hα chromospheric emission to examine the magnetic activity of the M dwarf in each system, and investigate how its activity is affected by the presence of a white dwarf companion. We find that the fraction of WD+dM binaries with active M dwarfs is significantly higher than their single M dwarf counterparts at early and mid-spectral types. We corroborate previous studies that find high activity fractions at both close and intermediate separations. At more distant separations, the binary fraction appears to approach the activity fraction for single M dwarfs. Using derived radial velocities and the proper motions, we calculate 3D space velocities for the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large vertical velocity dispersion, indicating a dynamically hotter population compared to high proper motion samples of single M dwarfs. We compare the kinematics for systems with active M dwarfs and those with inactive M dwarfs, and find signatures of asymmetric drift in the inactive sample, indicating that they are drawn from an older population. Based on observations obtained at the MDM Observatory operated by Dartmouth College, Columbia University, The Ohio State University, and the University of Michigan.

  3. Nordic hamstring exercise training alters knee joint kinematics and hamstring activation patterns in young men.

    Science.gov (United States)

    Delahunt, Eamonn; McGroarty, Mark; De Vito, Giuseppe; Ditroilo, Massimiliano

    2016-04-01

    To investigate the kinematic and muscle activation adaptations during performance of the Nordic hamstring exercise (NHE) to a 6-week eccentric hamstring training programme using the NHE as the sole mode of exercise. Twenty-nine healthy males were randomly allocated to a control (CG) or intervention (IG) group. The IG participated in a 6-week eccentric hamstring exercise programme using the NHE. The findings of the present study were that a 6-week eccentric hamstring training programme improved eccentric hamstring muscle strength (202.4 vs. 177.4 nm, p = 0.0002, Cohen's d = 0.97) and optimized kinematic (longer control of the forward fall component of the NHE, 68.1° vs. 73.7°, p = 0.022, Cohen's d = 0.90) and neuromuscular parameters (increased electromyographic activity of the hamstrings, 83.2 vs. 56.6 % and 92.0 vs. 54.2 %, p 1.25) associated with NHE performance. This study provides some insight into potential mechanisms by which an eccentric hamstring exercise programme utilizing the NHE as the mode of exercise may result in an improvement in hamstring muscle control during eccentric contractions.

  4. A kinematically beamed, low energy pulsed neutron source for active interrogation

    Science.gov (United States)

    Dietrich, Dan; Hagmann, Chris; Kerr, Phil; Nakae, Les; Rowland, Mark; Snyderman, Neal; Stoeffl, Wolfgang; Hamm, Robert

    2005-12-01

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of special nuclear materials (SNM) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals: (1) energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) neutrons with an energy of approximately 60-100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100 keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n, 2n) or (n, n‧) processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

  5. Gemini NIFS survey of feeding and feedback processes in nearby active galaxies - I. Stellar kinematics

    Science.gov (United States)

    Riffel, Rogemar A.; Storchi-Bergmann, Thaisa; Riffel, Rogerio; Dahmer-Hahn, Luis G.; Diniz, Marlon R.; Schönell, Astor J.; Dametto, Natacha Z.

    2017-09-01

    We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral resolution of 40 km s- 1. We find that the line-of-sight (LOS) velocity fields for most galaxies are well reproduced by rotating disc models. The kinematic position angle (PA) derived for the LOS velocity field is consistent with the large-scale photometric PA. The residual velocities are correlated with the hard X-ray luminosity, suggesting that more luminous active galactic nuclei have a larger impact in the surrounding stellar dynamics. The central velocity dispersion values are usually higher than the rotation velocity amplitude, what we attribute to the strong contribution of bulge kinematics in these inner regions. For 50 per cent of the galaxies, we find an inverse correlation between the velocities and the h3 Gauss-Hermitte moment, implying red wings in the blueshifted side and blue wings in the redshifted side of the velocity field, attributed to the movement of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational potential of a nuclear bar. Velocity dispersion (σ) maps show rings of low-σ values (˜50-80 km s- 1) for four objects and `patches' of low σ for six galaxies at 150-250 pc from the nucleus, attributed to young/ intermediate age stellar populations.

  6. Measuring supermassive black holes with gas kinematics: the active S0 galaxy NGC 3998

    CERN Document Server

    De Francesco, G; Marconi, A; Francesco, Giovanna De; Capetti, Alessandro; Marconi, Alessandro

    2006-01-01

    We present results from a kinematical study of the gas in the nucleus of the active S0 galaxy NGC 3998 obtained from archival HST/STIS long-slit spectra. We analyzed the emission lines profiles and derived the map of the gas velocity field. The observed velocity curves are consistent with gas in regular rotation around the galaxy's center. By modeling the surface brightness distribution and rotation curve of the H_alfa emission line we found that the observed kinematics of the circumnuclear gas can be accurately reproduced by adding to the stellar mass component a compact dark mass (black hole) of M_bh = 2.7(-2.0,+2.4) 10**8 M_sun (uncertainties at a 2 sigma level); the radius of its sphere of influence (R_sph ~ 0".16) is well resolved at the HST resolution. The BH mass estimate in NGC 3998 is in good agreement with both the M_bh vs. M_bul (with an upward scatter by a factor of ~2) and M_bh vs. sigma correlations (with a downward scatter by a factor of ~3-7, depending on the form adopted for the dependence of...

  7. Kinematic matrix theory and universalities in self-propellers and active swimmers

    Science.gov (United States)

    Nourhani, Amir; Lammert, Paul E.; Borhan, Ali; Crespi, Vincent H.

    2014-06-01

    We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

  8. Kinematic matrix theory and universalities in self-propellers and active swimmers.

    Science.gov (United States)

    Nourhani, Amir; Lammert, Paul E; Borhan, Ali; Crespi, Vincent H

    2014-06-01

    We describe an efficient and parsimonious matrix-based theory for studying the ensemble behavior of self-propellers and active swimmers, such as nanomotors or motile bacteria, that are typically studied by differential-equation-based Langevin or Fokker-Planck formalisms. The kinematic effects for elementary processes of motion are incorporated into a matrix, called the "kinematrix," from which we immediately obtain correlators and the mean and variance of angular and position variables (and thus effective diffusivity) by simple matrix algebra. The kinematrix formalism enables us recast the behaviors of a diverse range of self-propellers into a unified form, revealing universalities in their ensemble behavior in terms of new emergent time scales. Active fluctuations and hydrodynamic interactions can be expressed as an additive composition of separate self-propellers.

  9. ~100 Ma Lu-Hf eclogite ages from Koralpe and Saualpe (Austroalpine nappes, Austria): New constraints for the kinematics of Eoalpine subduction

    Science.gov (United States)

    Miladinova, Irena; Froitzheim, Nikolaus; Nagel, Thorsten; Janák, Marian; Münker, Carsten

    2016-04-01

    The Koralpe and Saualpe complexes are part of the Austroalpine basement nappe system. They represent the largest region in the Eastern Alps exposing high-pressure metamorphic rocks from the Cretaceous Eoalpine orogenic event and also contain the type locality for eclogite. The grade of the Cretaceous metamorphism in the Eastern Alps increases to the southeast, with maximum pressures and temperatures reaching up to 3.5 GPa and 850 °C in the Pohorje Mountains (Janak et al., 2015). The estimated P-T-conditions for the eclogites from Saualpe and Koralpe are 2-2.2 GPa and 600-740 °C (Miller & Thöni 1997, Thöni et al. 2008). Here we present a new Lu-Hf isotopic study of the eclogites from the Hohl locality in the southern Koralpe, and from the Grünburgerbach and Wolfsberger Hütte localities in the southern Saualpe. Two-point isochrones from samples of Hohl and Wolfsberger Hütte based on one whole rock and one garnet separate yield ages of 99.2 ± 1.1 Ma and 101.7 ± 2 Ma, respectively. Two eclogite samples from Grünburgerbach give garnet-omphacite-whole rock ages of 100.3 ± 1 Ma and 101.79 ± 0.92 Ma, identical within error. The garnets in the eclogite from Hohl display a homogenous composition with no zoning of major elements, whereas the garnets of the samples from Grünburgerbach show an enrichment of Mn in the cores and lower contents towards the rims, which indicates prograde garnet growth during increasing P and T. The ages are therefore related to burial during subduction. These new Lu-Hf garnet ages are slightly older than the Lu-Hf garnet age data from Pohorje (~95 Ma; Sandmann et al. 2011, Thöni et al. 2008), which also date burial. If Koralpe/Saualpe and Pohorje would belong to one continuous crustal unit subducted and exhumed "en bloc" in a southeast-dipping subduction zone, the opposite age difference would be expected. Our results show that this is not the case and represent important constraints for a more realistic kinematic model. Janak, M

  10. Differences in Muscle Activation and Kinematics Between Cable-Based and Selectorized Weight Training.

    Science.gov (United States)

    Signorile, Joseph F; Rendos, Nicole K; Heredia Vargas, Hector H; Alipio, Taislaine C; Regis, Rebecca C; Eltoukhy, Moataz M; Nargund, Renu S; Romero, Matthew A

    2017-02-01

    Signorile, JF, Rendos, NK, Heredia Vargas, HH, Alipio, TC, Regis, RC, Eltoukhy, MM, Nargund, RS, and Romero, MA. Differences in muscle activation and kinematics between cable-based and selectorized weight training. J Strength Cond Res 31(2): 313-322, 2017-Cable resistance training machines are showing resurgent popularity and allow greater number of degrees of freedom than typical selectorized equipment. Given that specific kinetic chains are used during distinct activities of daily living (ADL), cable machines may provide more effective interventions for some ADL, whereas others may be best addressed using selectorized equipment. This study examined differences in activity levels (root mean square of the EMG [rmsEMG]) of 6 major muscles (pectoralis major, PM; anterior deltoid, AD; biceps brachii, BB; rectus abdominis, RA; external obliques, EO; and triceps brachii, TB) and kinematics of multiple joints between a cable and standard selectorized machines during the biceps curl, the chest press, and the overhead press performed at 1.5 seconds per contractile stage. Fifteen individuals (9 men, 6 women; mean age ± SD, 24.33 ± 4.88 years) participated. Machine order was randomized. Significant differences favoring cable training were seen for PM and AD during biceps curl; BB, AD, and EO for chest press; and BB and EO during overhead press (p ≤ 0.05). Greater starting and ending angles were seen for the elbow and shoulder joints during selectorized biceps curl, whereas hip and knee starting and ending angles were greater for cable machine during chest and overhead presses (p < 0.0001). Greater range of motion (ROM) favoring the cable machine was also evident (p < 0.0001). These results indicate that utilization patterns of selected muscles, joint angles, and ROMs can be varied because of machine application even when similar exercises are used, and therefore, these machines can be used selectively in training programs requiring specific motor or biomechanical

  11. Kinematics of hip, knee, ankle of the young and elderly Chinese people during kneeling activity

    Institute of Scientific and Technical Information of China (English)

    Hai ZHOU; Dong-mei WANG; Tao-ran LIU; Xiang-sen ZENG; Cheng-tao WANG

    2012-01-01

    Objective:The purpose of this study was to measure the kinematics of the lower limbs of Chinese people during normal kneeling activity,as such data could be valuable in designing joint prosthesis and arthroplasty that meet the needs of Chinese citizens' daily activities.Methods:Thirty young and twenty elderly Chinese participants with no personal history of joint diseases were recruited,and matched by age (average age:23.8 years for the young group,60.8 years for the elderly group).Each participant performed six trials during which three-dimensional (3D) kinematics data were collected and the means of the 3D angles of the ankle,knee,and hip joints of two groups were calculated.Results:There were no obvious differences between the two groups in the knee and ankle joints.The mean range of knee flexion was 139.6° for the young group and 140.9° for the elderly group.The mean range of ankle flexion was 35.7° for the young group and 37.6° for the elderly group.The maximal eccentric flexion at the hip joint was 67.5° for the young group compared to 100.5° for the elderly group.Conclusions:The elderly uses more hip flexion angles than the young when assuming the kneeling posture.The ranges of motion obtained during kneeling activity are greater than the reported mean ranges of motion achieved following joint arthroplasty.The data could be valuable in establishing criteria for lower limb prosthetics and rehabilitation protocol for the Chinese population.

  12. Acute changes in kinematic and muscle activity patterns in habitually shod rearfoot strikers while running barefoot.

    Science.gov (United States)

    Strauts, Janina; Vanicek, Natalie; Halaki, Mark

    2016-01-01

    The aim of this study was to observe changes in the kinematics and muscle activities when barefoot running was initially adopted by six habitually shod, recreational rearfoot striking runners. Participants ran on a treadmill shod for 5 min, completed 3 × 10-min intervals of barefoot running and then completed a final minute of shod running at a self-selected pace. Dependent variables (speed, joint angles at foot-contact, joint range of motion (ROM), mean and peak electromyography (EMG) activity) were compared across conditions using repeated measures ANOVAs. Anterior pelvic tilt and hip flexion significantly decreased during barefoot conditions at foot contact. The ROM for the trunk, pelvis, knee and ankle angles decreased during the barefoot conditions. Mean EMG activity was reduced for biceps femoris, gastrocnemius lateralis and tibialis anterior during barefoot running. The peak activity across the running cycle decreased in biceps femoris, vastus medialis, gastrocnemius medialis and tibialis anterior during barefoot running. During barefoot running, tibialis anterior activity significantly decreased during the pre-activation and initial contact phases; gastrocnemius lateralis and medialis activity significantly decreased during the push-off phase. Barefoot running caused immediate biomechanical and neuromuscular adaptations at the hip and pelvis, which persisted when the runners donned their shoes, indicating that some learning had occurred during an initial short bout of barefoot running.

  13. Four-week exercise program does not change rotator cuff muscle activation and scapular kinematics in healthy subjects.

    Science.gov (United States)

    Lin, Yin-Liang; Karduna, Andrew

    2016-12-01

    Rotator cuff and scapular muscle strengthening exercises are an essential part of shoulder rehabilitation and sports training. Although the effect of exercise training on pain and function have been widely investigated, few studies have focused on the changes in shoulder kinematics and muscle activity after exercise training. Therefore, the purpose of the present study was to investigate the effect of rotator cuff and scapular strengthening exercises on shoulder kinematics and the activation of rotator cuff and scapular muscles in healthy subjects. Thirty-six healthy subjects were recruited and randomly assigned into either a training or control group. Subjects in the training group were trained with rotator cuff and scapular strengthening exercises for 4 weeks. Scapular kinematics and shoulder muscle activity during arm elevation were measured before and after exercise training. After the 4-week training protocol, there was an increase in strength and a decrease in upper trapezius activation in the training group, which is consistent with previous studies. However, no difference was found in scapular kinematics and activation of rotator cuff muscles between the control and training groups after the training protocol. Although the exercise protocol resulted in strength gains for the rotator cuff, these gains did not transfer to an increase in muscle activation during motion. These results demonstrate the difficulty in changing activation patterns of the rotator cuff muscles. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2079-2088, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  14. Kinematics of a giant slow-moving landslide in Northwest China: Constraints from high resolution remote sensing imagery and GPS monitoring

    Science.gov (United States)

    Jiang, Shu; Wen, Bao-Ping; Zhao, Cheng; Li, Rui-Dong; Li, Zhi-Heng

    2016-06-01

    Slow-moving landslides generally are long-lived and characterized by continuous movement with some fluctuation in sliding rate following changes of environmental factors, such as rainfall and earthquake. Analysis on kinematics of this type of landslide is essential for understanding its mechanism and identifying causal factors controlling its movement behavior. This paper presents a study on kinematics of a giant slow-moving landslide in northwest China, called the Xieliupo landslide, which is about 72 × 106 m3 in volume and has been slowly moving for more than 100 years. This study is conducted using archival high resolution remote sensing images from multi-sources over a period about 43 years and the data from 15-month GPS monitoring. Six sets of multi-source remote sensing images in 1969, 1971, 2004, 2008, 2010 and 2012 with spatial resolution higher than 2.5 m were used, and GPS monitoring data were recorded from September 2012 to December 2013. Obvious geomorphologic changes identified from the images in 1971 and 2004 confirm that this landslide did move slowly in the past. Quantitative analysis reveals that movement of the landslide was persistent and behaved in a block by block mode with the greatest and the least velocities in its middle and lower parts, respectively. Distance measurement between the homologous point pairs on the orthorectified images in 2005, 2010 and 2012 indicates that annual ground displacement of the landslide ranged from 0.52 m to 6.54 m in the seven years. GPS monitoring data shows that the landslide ground displacement in the 15 months varied from 0.49 m to 2.91 m, and annually between 0.39 m and 2.33 m, with a rather uniform movement pattern as identified using the remote sensing images. GPS monitoring results also reveal that the landslide movement is intermittent inter-annually. It is further discussed that movement behavior of the landslide is largely controlled by its topography with great influence of the active fault along

  15. Differences between kinematic synergies and muscle synergies during two-digit grasping

    Directory of Open Access Journals (Sweden)

    Michele eTagliabue

    2015-03-01

    Full Text Available The large number of mechanical degrees of freedom of the hand is not fully exploited during actual movements such as grasping. Usually, angular movements in various joints tend to be coupled, and EMG activities in different hand muscles tend to be correlated. The occurrence of covariation in the former was termed kinematic synergies, in the latter muscle synergies. This study addresses two questions: (i Whether kinematic and muscle synergies can simultaneously accommodate for kinematic and kinetic constraints. (ii If so, whether there is an interrelation between kinematic and muscle synergies. We used a reach-grasp-and-pull paradigm and recorded the hand kinematics as well as 8 surface EMGs. Subjects had to either perform a precision grip or side grip and had to modify their grip force in order to displace an object against a low or high load. The analysis was subdivided into three epochs: reach, grasp-and-pull, and static hold. Principal component analysis (PCA, temporal or static was performed separately for all three epochs, in the kinematic and in the EMG domain. PCA revealed that (i Kinematic- and muscle-synergies can simultaneously accommodate kinematic (grip type and kinetic task constraints (load condition. (ii Upcoming grip and load conditions of the grasp are represented in kinematic- and muscle-synergies already during reach. Phase plane plots of the principal muscle-synergy against the principal kinematic synergy revealed (iii that the muscle-synergy is linked (correlated, and in phase advance to the kinematic synergy during reach and during grasp-and-pull. Furthermore (iv, pair-wise correlations of EMGs during hold suggest that muscle-synergies are (in part implemented by coactivation of muscles through common input. Together, these results suggest that kinematic synergies have (at least in part their origin not just in muscular activation, but in synergiestic muscle activation. In short: kinematic synergies may result from muscle

  16. Shoulder kinematics and spatial pattern of trapezius electromyographic activity in real and virtual environments.

    Directory of Open Access Journals (Sweden)

    Afshin Samani

    Full Text Available The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE, virtual (VE, and virtual environment with force feedback (VEF with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles. High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform.

  17. The Long Term Evolution, Kinematics and Sediment Flux from an Active Earthflow

    Science.gov (United States)

    Mackey, B. H.; Roering, J. J.; McKean, J. A.

    2008-12-01

    Large, slow moving earthflows are pervasive in many rapidly eroding landscapes world wide. In the coast ranges of northern California, some earthflows are active (moving up to 2m/yr), but much of the landscape is imprinted with the ubiquitous subtle headscarps, toes and deflated transport zones from multiple generations of earthflows and landslides in various stages of dormancy. To better understand earthflow transport history and evolution, we aim to constrain the long term sediment flux, kinematics and topographic development of an individual earthflow. We undertake a multi-proxy study, focused on a 1.5km-long active earthflow entering Kekawaka Ck, an 85km2 tributary of the Eel River, southwest Trinity County, California. This classical earthflow has a steep amphitheater-like accumulation area which feeds into a narrow, elongate transport zone, and terminates at the creek in a bulbous toe. Combining high resolution digital topography from LiDAR, total station surveying, and a sequence of orthorectified historical aerial photographs, we generated displacement vectors of earthflow movement spanning the past 6 decades. The earthflow has a complex history of movement, with rates of activity varying through time and across the different kinematic zones of the earthflow complex. Horizontal movement rates range from 0.2-1m/yr and are greatest in the narrow mid-section of the earthflow, consistent with the dictates of mass conservation. Given direct observations of earthflow width and thickness at the hillslope-channel interface, we estimate the modern sediment flux attributable to mass movement to be 650 +/- 200 m3/yr. To extend our analysis to the millennial scale, we measured inventories of meteoric 10-Be in 4 soil pits down the flow axis, and one pit on unfailed terrain above the headscarp. The 10-Be depth profiles show how adjacent slopes enriched with >15kyr of 10-Be detach from the headscarp as the earthflow margin retrogresses upslope. These slump blocks

  18. Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?

    DEFF Research Database (Denmark)

    Mathevon, Nicolas; Aubin, Thierry; Dabelsteen, Torben

    2004-01-01

    and the temporal variations of the acoustic constraints, is especially useful to control the active space of signaling. The coding of information into acoustic parameters that have different susceptibility to propagation constraints is also of great interest. At the receiver’s level, an adaptive reception behavior...

  19. 3D shoulder kinematics for static vs dynamic and passive vs active testing conditions.

    Science.gov (United States)

    Robert-Lachaine, Xavier; Allard, Paul; Godbout, Véronique; Begon, Mickael

    2015-09-18

    Shoulder motion analysis provides clinicians with references of normal joint rotations. Shoulder joints orientations assessment is often based on series of static positions, while clinicians perform either passive or active tests and exercises mostly in dynamic. These conditions of motion could modify joint coordination and lead to discrepancies with the established references. Hence, the objective was to evaluate the influence of static vs dynamic and passive vs active testing conditions on shoulder joints orientations. Twenty asymptomatic subjects setup with 45 markers on the upper limb and trunk were tracked by an optoelectronic system. Static positions (30°, 60°, 90° and 120° of thoracohumeral elevation) and dynamic motion both in active condition and passively mobilised by an examiner were executed. Three-dimensional sternoclavicular, acromioclavicular, scapulothoracic and glenohumeral joint angles (12 in total) representing the distal segment orientation relative to the proximal segment orientation were estimated using a shoulder kinematical chain model. Separate four-way repeated measures ANOVA were applied on the 12 joint angles with factors of static vs dynamic, passive vs active, thoracohumeral elevation angle (30°, 60°, 90° and 120°) and plane of elevation (frontal and sagittal). Scapulothoracic lateral rotation progressed more during arm elevation in static than in dynamic gaining 4.2° more, and also in passive than in active by 6.6°. Glenohumeral elevation increased more during arm elevation in active than in passive by 4.4°. Shoulder joints orientations are affected by the testing conditions, which should be taken into consideration for data acquisition, inter-study comparison or clinical applications.

  20. Active constraints selection based semi-supervised dimensionality in ensemble subspaces

    Institute of Scientific and Technical Information of China (English)

    Jie Zeng; Wei Nie; Yong Zhang

    2015-01-01

    Semi-supervised dimensionality reduction (SSDR) has attracted an increasing amount of attention in this big-data era. Many algorithms have been developed with a smal number of pairwise constraints to achieve performances comparable to those of ful y supervised methods. However, one chal enging problem with semi-supervised approaches is the appropriate choice of the constraint set, including the cardinality and the composition of the constraint set, which to a large extent, affects the performance of the resulting algorithm. In this work, we address the problem by incorporating ensemble subspace and active learning into dimen-sionality reduction and propose a new algorithm, termed as global and local scatter based SSDR with active pairwise constraints selection in ensemble subspaces (SSGL-ESA). Unlike traditional methods that select the supervised information in one subspace, we pick up pairwise constraints in ensemble subspace, where a novel active learning algorithm is designed with both exploration and filtering to generate informative pairwise constraints. The auto-matic constraint selection approach proposed in this paper can be generalized to be used with al constraint-based semi-supervised learning algorithms. Comparative experiments are conducted on two face database and the results validate the effectiveness of the proposed method.

  1. Can generic knee joint models improve the measurement of osteoarthritic knee kinematics during squatting activity?

    Science.gov (United States)

    Clément, Julien; Dumas, Raphaël; Hagemeister, Nicola; de Guise, Jaques A

    2017-01-01

    Knee joint kinematics derived from multi-body optimisation (MBO) still requires evaluation. The objective of this study was to corroborate model-derived kinematics of osteoarthritic knees obtained using four generic knee joint models used in musculoskeletal modelling - spherical, hinge, degree-of-freedom coupling curves and parallel mechanism - against reference knee kinematics measured by stereo-radiography. Root mean square errors ranged from 0.7° to 23.4° for knee rotations and from 0.6 to 9.0 mm for knee displacements. Model-derived knee kinematics computed from generic knee joint models was inaccurate. Future developments and experiments should improve the reliability of osteoarthritic knee models in MBO and musculoskeletal modelling.

  2. Active load path adaption in a simple kinematic load-bearing structure due to stiffness change in the structure's supports

    Science.gov (United States)

    Gehb, C. M.; Platz, R.; Melz, T.

    2016-09-01

    Load-bearing structures with kinematic functions enable and disable degrees of freedom and are part of many mechanical engineering applications. The relative movement between a wheel and the body of a car or a landing gear and an aircraft fuselage are examples for load-bearing systems with defined kinematics. In most cases, the load is transmitted through a predetermined load path to the structural support interfaces. However, unexpected load peaks or varying health condition of the system's supports, which means for example varying damping and stiffness characteristics, may require an active adjustment of the load path. However, load paths transmitted through damaged or weakened supports can be the reason for reduced comfort or even failure. In this paper a simplified 2D two mass oscillator with two supports is used to numerically investigate the potential of controlled adaptive auxiliary kinematic guidance elements in a load-bearing structure to adapt the load path depending on the stiffness change, representing damage of the supports. The aim is to provide additional forces in the auxiliary kinematic guidance elements for two reasons. On the one hand, one of the two supports that may become weaker through stiffness change will be relieved from higher loading. On the other hand, tilting due to different compliance in the supports will be minimized. Therefore, shifting load between the supports during operation could be an effective option.

  3. Accretion/jet activity and narrow [O III] kinematics in young radio galaxies

    Institute of Scientific and Technical Information of China (English)

    Andrew; HUMPHREY

    2010-01-01

    We estimate black hole masses and Edenton ratios for a sample of 81 young radio galaxies,which includes 42 compact steep-spectrum(CSS) and 39 gigahertz-peaked spectrum(GPS) sources.We find that the average black hole(BH) mass of these young radio galaxies is〈log Mbh〉-8.3,which is less than that of radio loud QSOs and low redshift radio galaxies(〈 log Mbh〉-9.0).The CSS/GPS sources have relatively high Eddington ratios,with an average value of〈log Lbol/LEdd〉=-0.75,which are similar to those of narrow line Seyfert 1 galaxies(NLS1s).This suggests that young radio galaxies may not only be in the early stages of their radio activity,but also in the early stage of their accretion activity.We find that the young radio galaxies,as a class,systematically deviate from the Mbh-σ relation defined by nearby inactive galaxies,when using σ[O III] as a surrogate for stellar velocity dispersion σ.We also find that the deviation of the [O III] line width,Δσ =σ[O III]-σ[pred],is correlated with the Eddington ratio;sources with Lbol/LEdd-1 have the largest deviations,which are similar to those of radio quiet QSOs/NLS1s(i.e.,sources in which the radio jets are absent or weak),and where σ[pred] is calculated from the Tremaine et al.relation using our estimated BH masses.A similar result has been obtained for 9 linear radio Seyfert galaxies.On the basis of these results,we suggest that,in addition to the possible jet-gas interactions,accretion activities may also play an important role in shaping the kinematics of the narrow [O III] line in young radio galaxies.

  4. Electromyographic activity of the jaw muscles and mandibular kinematics in young adults with theoretically ideal dental occlusion: Reference values.

    Science.gov (United States)

    Campillo, B; Martín, C; Palma, J-C; Fuentes, A-D; Alarcón, J-A

    2017-05-01

    A necessary step to use neuromuscular analysis as diagnostic tool is to establish normal reference values for the physiological range in a healthy population. Surface electromyographic (sEMG) activity of the jaw muscles and mandibular kinematics were measured in young adults with theoretically ideal dental occlusion to determine normal reference values during different tasks. Differences between the sexes were evaluated. Forty young adults (20 men, 20 women; mean age 22.8 ± 3.9 years) with theoretically ideal dental occlusion were selected using very restrictive criteria. sEMG activity of the anterior temporalis (AT), posterior temporalis, masseter (MA), and suprahyoid muscles were evaluated in the rest position and during swallowing, mastication, and clenching. Mandibular kinematics in the rest position and during maximum excursions were assessed. Asymmetry, activity, and torque indices and MA/AT ratios were calculated. For all muscles, sEMG values were 1.01-3.57 µV at rest, 3.50-10.85 µV during swallowing, and 41.04-86.59 µV during mastication. During clenching, values were 230.08-243.55 µV for the AT and MA muscles. Mean total asymmetry, activity, and torque indices at rest were 20.34 %, -15.04 %, and 19.02 %, respectively; during clenching, these values were 6.14 %, -2.62 %, and 4.46 %. MA/AT ratios were near 1. Kinematic measurements during lateral excursion, protrusive and maximum opening were 7.54, 8.44, and 37.38 mm respectively; lateral mandibular shift was 1.41 mm; free way and lateral displacement at rest were 1.40 and 0.26 mm. Right MA activity during mastication and clenching was higher in men than women. Reference values for sEMG activity and mandibular kinematics were determined. Some muscular asymmetry and torque were observed.

  5. STELLAR KINEMATICS AND STRUCTURAL PROPERTIES OF VIRGO CLUSTER DWARF EARLY-TYPE GALAXIES FROM THE SMAKCED PROJECT. III. ANGULAR MOMENTUM AND CONSTRAINTS ON FORMATION SCENARIOS

    Energy Technology Data Exchange (ETDEWEB)

    Toloba, E.; Guhathakurta, P. [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Boselli, A.; Boissier, S. [Aix Marseille Universit, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Peletier, R. F. [Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen (Netherlands); Emsellem, E. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Lisker, T. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Van de Ven, G. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Simon, J. D.; Adams, J. J.; Benson, A. J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Falcón-Barroso, J.; Ryś, A. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38200 La Laguna, Tenerife (Spain); Den Brok, M. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Gorgas, J. [Departamento de Astrofísica y Ciencias de la Atmósfera, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Hensler, G. [Department of Astrophysics, University of Vienna, Türkenschanzstraße 17, A-1180 Vienna (Austria); Janz, J. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Laurikainen, E.; Salo, H. [Division of Astronomy, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland); Paudel, S., E-mail: toloba@ucolick.org [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2015-02-01

    We analyze the stellar kinematics of 39 dwarf early-type galaxies (dEs) in the Virgo Cluster. Based on the specific stellar angular momentum λ{sub Re} and the ellipticity, we find 11 slow rotators and 28 fast rotators. The fast rotators in the outer parts of the Virgo Cluster rotate significantly faster than fast rotators in the inner parts of the cluster. Moreover, 10 out of the 11 slow rotators are located in the inner 3° (D < 1 Mpc) of the cluster. The fast rotators contain subtle disk-like structures that are visible in high-pass filtered optical images, while the slow rotators do not exhibit these structures. In addition, two of the dEs have kinematically decoupled cores and four more have emission partially filling in the Balmer absorption lines. These properties suggest that Virgo Cluster dEs may have originated from late-type star-forming galaxies that were transformed by the environment after their infall into the cluster. The correlation between λ{sub Re} and the clustercentric distance can be explained by a scenario where low luminosity star-forming galaxies fall into the cluster, their gas is rapidly removed by ram-pressure stripping, although some of it can be retained in their core, their star formation is quenched but their stellar kinematics are preserved. After a long time in the cluster and several passes through its center, the galaxies are heated up and transformed into slow rotating dEs.

  6. Mid-J CO shock tracing observations of infrared dark clouds II Low-J CO constraints on excitation, depletion, and kinematics

    CERN Document Server

    Pon, A; Caselli, P; Fontani, F; Palau, A; Butler, M J; Kaufman, M; Jiménez-Serra, I; Tan, J C

    2015-01-01

    Infrared dark clouds are kinematically complex molecular structures in the interstellar medium that can host sites of massive star formation. We present 4 square arcminute maps of the 12CO, 13CO, and C18O J = 3 to 2 lines from selected locations within the C and F (G028.37+00.07 and G034.43+00.24) infrared dark clouds (IRDCs), as well as single pointing observations of the 13CO and C18O J = 2 to 1 lines towards three cores within these clouds. We derive CO gas temperatures throughout the maps and find that CO is significantly frozen out within these IRDCs. We find that the CO depletion tends to be the highest near column density peaks, with maximum depletion factors between 5 and 9 in IRDC F and between 16 and 31 in IRDC C. We also detect multiple velocity components and complex kinematic structure in both IRDCs. Therefore, the kinematics of IRDCs seem to point to dynamically evolving structures yielding dense cores with considerable depletion factors.

  7. Kinematic analysis of the daily activity of drinking from a glass in a population with cervical spinal cord injury

    Directory of Open Access Journals (Sweden)

    de los Reyes-Guzmán Ana

    2010-08-01

    Full Text Available Abstract Background Three-dimensional kinematic analysis equipment is a valuable instrument for studying the execution of movement during functional activities of the upper limbs. The aim of this study was to analyze the kinematic differences in the execution of a daily activity such as drinking from a glass between two groups of patients with tetraplegia and a control group. Methods A total of 24 people were separated into three groups for analysis: 8 subjects with metameric level C6 tetraplegia, 8 subjects with metameric level C7 tetraplegia and 8 control subjects (CG. A set of active markers that emit infrared light were positioned on the upper limb. Two scanning units were used to record the sessions. The activity of drinking from a glass was broken down into a series of clearly identifiable phases to facilitate analysis. Movement times, velocities, and the joint angles of the shoulder, elbow and wrist in the three spatial planes were the variables analyzed. Results The most relevant differences between the three groups were in the wrist. Wrist palmar flexion during the back transport phase was greater in the patients with C6 and C7 tetraplegia than in the CG, whereas the highest wrist dorsal flexion values were in forward transport in the subjects with C6 or C7 tetraplegia, who required complete activation of the tenodesis effect to complete grasping. Conclusions A detailed description was made of the three-dimensional kinematic analysis of the task of drinking from a glass in healthy subjects and in two groups of patients with tetraplegia. This was a useful application of kinematic analysis of upper limb movement in a clinical setting. Better knowledge of the execution of this movement in each of these groups allows therapeutic recommendations to be specifically adapted to the functional deficit present. This information can be useful in designing wearable robots to compensate the performance of AVD, such as drinking, in people with

  8. A Double-Ring Algorithm for Modeling Solar Active Regions: Unifying Kinematic Dynamo Models and Surface Flux-Transport Simulations

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Martens, Petrus C H; Yeates, Anthony R

    2010-01-01

    The emergence of tilted bipolar active regions and the dispersal of their flux, mediated via processes such as diffusion, differential rotation and meridional circulation is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed $\\alpha$-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithm for modeling the Babcock-Leighton mechanism based on active region eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations we first show that an axisymmetric formulation -- which is usually invoked in kinematic dynamo models -- can reasonably approximate the surface flux dy...

  9. Effect of Kayak Ergometer Elastic Tension on Upper Limb EMG Activity and 3D Kinematics.

    Science.gov (United States)

    Fleming, Neil; Donne, Bernard; Fletcher, David

    2012-01-01

    Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10) performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces. Key pointsKayak ergometer elastic tension significantly alters Anterior Deltoid recruitment patterns.Kayakers maintain optimal arm kinematics despite changing external forces via altered shoulder muscle recruitment.Overhead arm movements account for a high proportion of the kayak stroke cycle.

  10. Scaling and kinematics optimisation of the scapula and thorax in upper limb musculoskeletal models.

    Science.gov (United States)

    Prinold, Joe A I; Bull, Anthony M J

    2014-08-22

    Accurate representation of individual scapula kinematics and subject geometries is vital in musculoskeletal models applied to upper limb pathology and performance. In applying individual kinematics to a model's cadaveric geometry, model constraints are commonly prescriptive. These rely on thorax scaling to effectively define the scapula's path but do not consider the area underneath the scapula in scaling, and assume a fixed conoid ligament length. These constraints may not allow continuous solutions or close agreement with directly measured kinematics. A novel method is presented to scale the thorax based on palpated scapula landmarks. The scapula and clavicle kinematics are optimised with the constraint that the scapula medial border does not penetrate the thorax. Conoid ligament length is not used as a constraint. This method is simulated in the UK National Shoulder Model and compared to four other methods, including the standard technique, during three pull-up techniques (n=11). These are high-performance activities covering a large range of motion. Model solutions without substantial jumps in the joint kinematics data were improved from 23% of trials with the standard method, to 100% of trials with the new method. Agreement with measured kinematics was significantly improved (more than 10° closer at pthorax scaling correction factor were shown to be key. Separation of the medial border of the scapula from the thorax was large, although this may be physiologically correct due to the high loads and high arm elevation angles. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. The initial superposition of oceanic and continental units in the southern Western Alps: constraints on geometrical restoration and kinematics of the continental subduction wedge

    Science.gov (United States)

    Dumont, Thierry; Schwartz, Stéphane; Matthews, Steve; Malusa, Marco; Jouvent, Marine

    2017-04-01

    The tectonic contact separating continental and oceanic units is preserved at outcrop in many locations within the Western Alps. The contact has experienced prolonged and progressive deformation during Oligocene collision and subsequent 'extrusive' contraction which is approximately westerly-directed (Dumont et al., 2012). Despite variable metamorphic grade, this tectonic contact displays a relative consistency of tectonostratigraphic and structural characteristics. Removal of the Oligocene and younger deformation is a critical requirement to allow assessment of the kinematic evolution during the Eocene continental subduction phase. The best preserved relationships are observed near the base of the Helminthoid Flysch nappes, in the footwall of the Penninic thrust, or in the external part of the Briançonnais zone. Here, the oceanic units are composed of detached Cretaceous sediments, but they are underlain locally by an olistostrome containing basaltic clasts. Further to the east, the internal boundary of the Briançonnais zone s.l. (including the 'Prepiedmont units'), is frequently marked by breccia or megabreccia, but is strongly affected by blueschist-facies metamorphism and by approximately easterly directed backfolding and backthrusting. At one locality, there is compelling evidence that the oceanic and continental units were already tectonically stacked and metamorphosed (together) 32Ma ago. Some megabreccias of mixed continental/oceanic provenance can be interpreted as a metamorphic equivalent of the external olistostrome, products of the initial pulses of tectonic stacking. The overlying units are composed dominantly of metasediments, containing distributed ophiolitic megaboudins (Tricart & Schwartz, 2006). Further east again, the tectonic contact separates the Dora-Maira continental basement from the Mt. Viso units which are predominantly composed of oceanic lithosphere. Both the Dora-Maira and Mt. Viso units are eclogitic, but the HP peak is apparently

  12. Radially extended kinematics and stellar populations of the massive ellipticals NGC1600, NGC4125 and NGC7619. Constraints on the outer dark halo density profile

    CERN Document Server

    Pu, S B; Fabricius, M H; Thomas, J; Bender, R; Han, Z

    2010-01-01

    We present high quality long slit spectra along the major and minor axes out to 1.5-2 Re (14-22 kpc) of three bright elliptical galaxies (NGC1600, NGC4125, NGC7619) obtained at the Hobby-Eberly Telescope (HET). We derive stellar kinematic profiles and Lick/IDS indices (Hbeta, Mgb, Fe5015, Fe5270, Fe5335, Fe5406). Moreover, for NGC4125 we derive gas kinematics and emission line strengths. We model the absorption line strengths using Simple Stellar Populations models that take into account the variation of [\\alpha/Fe] and derive ages, total metallicity and element abundances. Overall, we find that the three galaxies have old and [\\alpha/Fe] overabundant stellar populations with no significant gradients. The metallicity is supersolar at the center with a strong negative radial gradient. For NGC4125, several pieces of evidence point to a recent dissipational merger event. We calculate the broad band color profiles with the help of SSP models. All of the colors show sharp peaks at the center of the galaxies, mainl...

  13. Relativistic Kinematics

    CERN Document Server

    Sahoo, Raghunath

    2016-01-01

    This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.

  14. Walking while performing working memory tasks changes the prefrontal cortex hemodynamic activations and gait kinematics

    Directory of Open Access Journals (Sweden)

    Ming-I Brandon Lin

    2016-05-01

    Full Text Available BackgroundIncreasing evidence suggests that walking while performing a concurrent task negatively influences gait performance. However, it remains unclear how higher-level cognitive processes and coordination of limb movements are altered in challenging walking environments. This study investigated the influence of cognitive task complexity and walking road condition on the neutral correlates of executive function and postural control in dual-task walking. MethodsTwenty-four healthy young adults completed a series of overground walks with three walking road conditions (wide, narrow, with obstacles with and without the concurrent n-back working memory tasks of two complexity levels (1-back and 3-back. Prefrontal brain activation was assessed by functional near-infrared spectroscopy. A three-dimensional motion analysis system was used simultaneously to measure gait performance and lower-extremity kinematics. Repeated measures analysis of variance were performed to examine the differences between the conditions. ResultsIn comparison with standing still, participants showed lower n-back task accuracy while walking, with the worst performance from the road with obstacles. Spatiotemporal gait parameters, lower-extremity joint movements, and the relative changes in oxygenated hemoglobin (HbO concentration levels were all significantly different across the task complexity and walking path conditions. While dual-tasking participants were found to flex their hips and knees less, leading to a slower gait speed, longer stride time, shorter step length, and greater gait variability than during normal walking. For narrow-road walking, smaller ankle dorsiflexion and larger hip flexion were observed, along with a reduced gait speed. Obstacle negotiation was mainly characterized by increased gait variability than other conditions. HbO levels appeared to be lower during dual-task walking than normal walking. Compared to wide and obstacle conditions, walking on

  15. Modelling Activities In Kinematics Understanding quantitative relations with the contribution of qualitative reasoning

    Science.gov (United States)

    Orfanos, Stelios

    2010-01-01

    In Greek traditional teaching a lot of significant concepts are introduced with a sequence that does not provide the students with all the necessary information required to comprehend. We consider that understanding concepts and the relations among them is greatly facilitated by the use of modelling tools, taking into account that the modelling process forces students to change their vague, imprecise ideas into explicit causal relationships. It is not uncommon to find students who are able to solve problems by using complicated relations without getting a qualitative and in-depth grip on them. Researchers have already shown that students often have a formal mathematical and physical knowledge without a qualitative understanding of basic concepts and relations." The aim of this communication is to present some of the results of our investigation into modelling activities related to kinematical concepts. For this purpose, we have used ModellingSpace, an environment that was especially designed to allow students from eleven to seventeen years old to express their ideas and gradually develop them. The ModellingSpace enables students to build their own models and offers the choice of observing directly simulations of real objects and/or all the other alternative forms of representations (tables of values, graphic representations and bar-charts). The students -in order to answer the questions- formulate hypotheses, they create models, they compare their hypotheses with the representations of their models and they modify or create other models when their hypotheses did not agree with the representations. In traditional ways of teaching, students are educated to utilize formulas as the most important strategy. Several times the students recall formulas in order to utilize them, without getting an in-depth understanding on them. Students commonly use the quantitative type of reasoning, since it is primarily used in teaching, although it may not be fully understood by them

  16. Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study.

    Science.gov (United States)

    Müller, Juliane; Müller, Steffen; Engel, Tilman; Reschke, Antje; Baur, Heiner; Mayer, Frank

    2016-04-11

    Reflex activity of the lower leg muscles involved when compensating for falls has already been thoroughly investigated. However, the trunk׳s role in this compensation strategy remains unclear. The purpose of this study, therefore, was to analyze the kinematics and muscle activity of the trunk during perturbed walking. Ten subjects (29 ± 3 yr;79 ± 11 cm;74 ± 14 kg) walked (1m/s) on a split-belt treadmill, while 5 randomly timed, right-sided perturbations (treadmill belt deceleration: 40 m/s(2)) were applied. Trunk muscle activity was assessed with a 12-lead-EMG. Trunk kinematics were measured with a 3D-motion analysis system (12 markers framing 3 segments: upper thoracic area (UTA), lower thoracic area (LTA), lumbar area (LA)). The EMG-RMS [%] (0-200 ms after perturbation) was analyzed and then normalized to the RMS of normal walking. The total range of motion (ROM;[°]) for the extension/flexion, lateral flexion and rotation of each segment were calculated. Individual kinematic differences between walking and stumbling [%; ROM] were also computed. Data analysis was conducted descriptively, followed by one- and two-way ANOVAs (α=0.05). Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 ± 26% (UTA/rotation) and 262 ± 132% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 ± 283%; back: 501 ± 215%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling.

  17. Interactive activation and mutual constraint satisfaction in perception and cognition.

    Science.gov (United States)

    McClelland, James L; Mirman, Daniel; Bolger, Donald J; Khaitan, Pranav

    2014-08-01

    In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis-the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive activation model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that

  18. New Supernova Constraints on active-sterile neutrino conversions

    OpenAIRE

    Pastor Carpi, Sergio; Semikoz, Victor B.; Furtado Valle, José Wagner

    1994-01-01

    We consider active-sterile neutrino conversions in a supernova in the presence of random magnetic field domains. For large enough fields the magnetization of the medium may enhance the active to sterile neutrino conversion rates. Neglecting neutrino transition magnetic moments we show that for keV neutrino mass squared differences these limits may overcome those that would apply in the case of zero magnetic field.

  19. On Implicit Active Constraints in Linear Semi-Infinite Programs with Unbounded Coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Goberna, M. A., E-mail: mgoberna@ua.es [Alicante University, Dep. of Statistics and Operations Research (Spain); Lancho, G. A., E-mail: lanchoga@mixteco.utm.mx [Universidad Tecnologica de Mixteca, Instituto de Fisica y Matematicas (Mexico); Todorov, M. I., E-mail: maxim.todorov@udlap.mx [UDLA, Dep. of Physics and Mathematics (Mexico); Vera de Serio, V. N., E-mail: vvera@uncu.edu.ar [Universidad Nacional de Cuyo, Facultad de Ciencias Economicas, Instituto de Ciencias Basicas (Argentina)

    2011-04-15

    The concept of implicit active constraints at a given point provides useful local information about the solution set of linear semi-infinite systems and about the optimal set in linear semi-infinite programming provided the set of gradient vectors of the constraints is bounded, commonly under the additional assumption that there exists some strong Slater point. This paper shows that the mentioned global boundedness condition can be replaced by a weaker local condition (LUB) based on locally active constraints (active in a ball of small radius whose center is some nominal point), providing geometric information about the solution set and Karush-Kuhn-Tucker type conditions for the optimal solution to be strongly unique. The maintaining of the latter property under sufficiently small perturbations of all the data is also analyzed, giving a characterization of its stability with respect to these perturbations in terms of the strong Slater condition, the so-called Extended-Nuernberger condition, and the LUB condition.

  20. Decoding Lower Limb Muscle Activity and Kinematics from Cortical Neural Spike Trains during Monkey Performing Stand and Squat Movements.

    Science.gov (United States)

    Ma, Xuan; Ma, Chaolin; Huang, Jian; Zhang, Peng; Xu, Jiang; He, Jiping

    2017-01-01

    Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1). Two monkeys were used in this study. Subdermal intramuscular EMG electrodes were implanted to 8 right leg/thigh muscles. With ample data collected from neurons from a large brain area, we performed a spike triggered average (SpTA) analysis and got a series of density contours which revealed the spatial distributions of different muscle-innervating neurons corresponding to each given muscle. Based on the guidance of these results, we identified the locations optimal for chronic electrode implantation and subsequently carried on chronic neural data recordings. A recursive Bayesian estimation framework was proposed for decoding EMG signals together with kinematics from M1 spike trains. Two specific algorithms were implemented: a standard Kalman filter and an unscented Kalman filter. For the latter one, an artificial neural network was incorporated to deal with the nonlinearity in neural tuning. High correlation coefficient and signal to noise ratio between the predicted and the actual data were achieved for both EMG signals and kinematics on both monkeys. Higher decoding accuracy and faster convergence rate could be achieved with the unscented Kalman filter. These results demonstrate that lower limb EMG signals and kinematics during monkey stand/squat can be accurately decoded from a group of M1 neurons with the proposed

  1. Decoding Lower Limb Muscle Activity and Kinematics from Cortical Neural Spike Trains during Monkey Performing Stand and Squat Movements

    Science.gov (United States)

    Ma, Xuan; Ma, Chaolin; Huang, Jian; Zhang, Peng; Xu, Jiang; He, Jiping

    2017-01-01

    Extensive literatures have shown approaches for decoding upper limb kinematics or muscle activity using multichannel cortical spike recordings toward brain machine interface (BMI) applications. However, similar topics regarding lower limb remain relatively scarce. We previously reported a system for training monkeys to perform visually guided stand and squat tasks. The current study, as a follow-up extension, investigates whether lower limb kinematics and muscle activity characterized by electromyography (EMG) signals during monkey performing stand/squat movements can be accurately decoded from neural spike trains in primary motor cortex (M1). Two monkeys were used in this study. Subdermal intramuscular EMG electrodes were implanted to 8 right leg/thigh muscles. With ample data collected from neurons from a large brain area, we performed a spike triggered average (SpTA) analysis and got a series of density contours which revealed the spatial distributions of different muscle-innervating neurons corresponding to each given muscle. Based on the guidance of these results, we identified the locations optimal for chronic electrode implantation and subsequently carried on chronic neural data recordings. A recursive Bayesian estimation framework was proposed for decoding EMG signals together with kinematics from M1 spike trains. Two specific algorithms were implemented: a standard Kalman filter and an unscented Kalman filter. For the latter one, an artificial neural network was incorporated to deal with the nonlinearity in neural tuning. High correlation coefficient and signal to noise ratio between the predicted and the actual data were achieved for both EMG signals and kinematics on both monkeys. Higher decoding accuracy and faster convergence rate could be achieved with the unscented Kalman filter. These results demonstrate that lower limb EMG signals and kinematics during monkey stand/squat can be accurately decoded from a group of M1 neurons with the proposed

  2. Exploring variation in active network size : Constraints and ego characteristics

    NARCIS (Netherlands)

    Roberts, Sam G. B.; Dunbar, Robin I. M.; Pollet, Thomas V.; Kuppens, Toon

    2009-01-01

    Studies of active personal networks have primarily focused on providing reliable estimates of the size of the network. In this study, we examine how compositional properties of the network and ego characteristics are related to Variation in network size. There was a negative relationship between mea

  3. Change of Muscle Activity as Well as Kinematic and Kinetic Parameters during Headers after Core Muscle Fatigue

    Directory of Open Access Journals (Sweden)

    Stephan Becker

    2017-01-01

    Full Text Available In soccer, headers are a tactical measure and influenced by numerous factors. The goal of this study was to identify whether changes in kinematics and muscular activity, especially of the head-stabilizing muscles, occur during headers when the core musculature is fatigued. In two subgroups, muscular activity (12 amateur players, age 23.6 ± 4.2 years and kinematics and dynamics (29 amateur players, age 23.7 ± 2.8 years were examined during straight headers on a pendulum header. Data were collected before and after the core muscles were fatigued by an exercise program. Telemetric surface EMG, 3D acceleration sensor, force plate, and video recordings were used. Under fatigue, the activity of M. erector spinae and M. rectus abdominis was significantly reduced in the preparation phase of the header. The activity of M. sternocleidomastoideus was significantly increased during the jump phase, and the hip extension angle during maximum arched body tension was significantly reduced under fatigue. Jumping height, acceleration force impulse, and linear head acceleration were also significantly reduced. We conclude that fatigue of the core muscles affects the motion technique of the header and the activity of the muscle groups stabilizing the head. Therefore, the necessity of specific training in soccer should be emphasized from a medical-preventive point of view.

  4. Constraints on the Star Formation Rate in Active Galaxies

    CERN Document Server

    Kim, M; Im, M; Kim, Minjin; Ho, Luis C.; Im, Myungshin

    2006-01-01

    The [O II] 3727 emission line is often used as an indicator of star formation rate in extragalactic surveys, and it can be an equally effective tracer of star formation in systems containing luminous active galactic nuclei (AGNs). In order to investigate the ongoing star formation rate of the host galaxies of AGNs, we measured the strength of [O II] and other optical emission lines from a large sample (~ 3600) of broad-line (Type 1) AGNs selected from the Sloan Digital Sky Survey. We performed a set of photoionization calculations to help evaluate the relative contribution of stellar and nonstellar photoionization to the observed strength of [O II]. Consistent with the recent study of Ho (2005), we find that the observed [O II] emission can be explained entirely by photoionization from the AGN itself, with little or no additional contribution from HII regions. This indicates that the host galaxies of Type 1 AGNs experience very modest star formation concurrent with the optically active phase of the nucleus. B...

  5. Kinematics of the Neogene Terror Rift: Constraints from calcite twinning strain in AND-1B core, McMurdo Ice Shelf

    Science.gov (United States)

    Paulsen, T.; Wilson, T. J.; Demosthenous, C.; Millan, C.; Jarrard, R. D.; Laufer, A.

    2013-12-01

    Strain analyses of mechanically twinned calcite in veins and faults hosted by Neogene (13.6 Ma to 4.3 Ma) sedimentary and volcanic rocks recovered within the ANDRILL AND-1B drill core from the Terror Rift in the southern Ross Sea, Antarctica, yield prolate and oblate ellipsoids with principal shortening and extension strains ranging from 0.1% to 8.5%. The majority of samples show homogeneous coaxial strain predominantly characterized by subvertical shortening, which we attribute to lithostatic loading in an Andersonian normal faulting stress regime during sedimentary and ice sheet burial of the stratigraphic sequence. The overall paucity of a non-coaxial layer-parallel shortening signal in the AND-1B twin populations suggests that horizontal compressive stresses predicted by Neogene transtensional kinematic models for the rift system have been absent or of insufficient magnitude to cause a widespread noncoaxial strain overprint. Limited numbers of oriented samples yield a possible average ESE extension direction for the rift that is subparallel to other indicators of Neogene extension. The lack of horizontal shortening in the twin data suggests the Neogene Terror Rift system either lacks a strong longitudinal strike-slip component, or that spatial partitioning of strain controls the maximum shortening axes seen in rocks of this age.

  6. Active Control Strategy for Offshore Structures Accounting for AMD Constraints

    Institute of Scientific and Technical Information of China (English)

    Ji Chunyan(嵇春艳); Li Huajun; Meng Qingmin

    2004-01-01

    Most of active mass damper systems are designed or installed for the onshore structural response reduction to quite small earthquake or strong wind excitation. When they are applied to offshore structures, they will stop their operations during severe sea state (including strong wind, wave and fluid). For controlling the excessive vibration of offshore structure excited by wave loading, this paper presents a methodology keeping AMD operations even in severe sea state. And the controller was designed by LQG control algorithm accounting for the limits of AMD stroke and control input force. In order to investigate the feasibility and effectiveness of the proposed method, a numerical example applied to an offshore platform is presented in this paper. The numerical results demonstrate that the proposed algorithm is effective in reducing the vibration of offshore structure by choosing appropriate feedback gain among several gain candidates based on the AMD limits.

  7. Extravehicular Activity Operations Concepts Under Communication Latency and Bandwidth Constraints

    Science.gov (United States)

    Beaton, Kara H.; Chappell, Steven P.; Abercromby, Andrew F. J.; Miller, Matthew J.; Nawotniak, Shannon Kobs; Hughes, Scott; Brady, Allyson; Lim, Darlene S. S.

    2017-01-01

    The Biologic Analog Science Associated with Lava Terrains (BASALT) project is a multi-year program dedicated to iteratively develop, implement, and evaluate concepts of operations (ConOps) and supporting capabilities intended to enable and enhance human scientific exploration of Mars. This pa-per describes the planning, execution, and initial results from the first field deployment, referred to as BASALT-1, which consisted of a series of 10 simulated extravehicular activities (EVAs) on volcanic flows in Idaho's Craters of the Moon (COTM) National Monument. The ConOps and capabilities deployed and tested during BASALT-1 were based on previous NASA trade studies and analog testing. Our primary research question was whether those ConOps and capabilities work acceptably when performing real (non-simulated) biological and geological scientific exploration under 4 different Mars-to-Earth communication conditions: 5 and 15 min one-way light time (OWLT) communication latencies and low (0.512 Mb/s uplink, 1.54 Mb/s downlink) and high (5.0 Mb/s uplink, 10.0 Mb/s downlink) bandwidth conditions representing the lower and higher limits of technical communication capabilities currently proposed for future human exploration missions. The synthesized results of BASALT-1 with respect to the ConOps and capabilities assessment were derived from a variety of sources, including EVA task timing data, network analytic data, and subjective ratings and comments regarding the scientific and operational acceptability of the ConOp and the extent to which specific capabilities were enabling and enhancing, and are presented here. BASALT-1 established preliminary findings that baseline ConOp, software systems, and communication protocols were scientifically and operationally acceptable with minor improvements desired by the "Mars" extravehicular (EV) and intravehicular (IV) crewmembers, but unacceptable with improvements required by the "Earth" Mission Support Center. These data will provide a

  8. Modelado de Materiales Compuestos por Elementos Finitos usando Restricciones Cinemáticas Finite Element Modeling of Composite Materials using Kinematic Constraints

    Directory of Open Access Journals (Sweden)

    Oscar E. Ruiz

    2009-12-01

    Full Text Available El propósito de este artículo es presentar simulaciones del comportamiento de materiales compuestos basado en restricciones cinemáticas entre las mismas fibras y entre las fibras y la resina circundante. En la revisión de literatura, los autores han encontrado que las restricciones cinemáticas no han sido plenamente explotadas para modelar materiales compuestos, probablemente debido a su alto costo computacional. El propósito de este articulo es exponer la implementación y resultados de tal modelo, usando Análisis por Elementos Finitos de restricciones geométricas prescritas a los nodos de la resina y las fibras. Las descripciones analíticas del comportamiento de materiales compuestos raramente aparecen. Muchas aproximaciones para describir materiales compuestos en capas son basadas en la teoría de funciones C1Z y C0 Z, tal como la Teoría Clásica de Capas (CLT. Estas teorías de funciones contienen significativas simplificaciones del material, especialmente para compuestos tejidos. Una aproximación hibrida para modelar materiales compuestos con Elementos Finitos (FEA fue desarrollada por Sidhu y Averill y adaptada por Li y Sherwood para materiales compuestos tejidos con polipropileno de vidrio.The purpose of this article is to present simulations of the behavior of composite materials based on kinematic restrictions among the fibers themselves and among fibers and the surrounding resine. In the literature review the authors have found that the kinematic restrictions have not been fully exploited for modeling composite materials, probably due to their high computational expense. The purpose of this article is to show the implementation and results of such a model, by using a Finite Element Analysis of geometric restrictions prescribed to the resine and fiber nodes. Closed analytic descriptions on behavior of layered composite materials are very rare. Many approaches to describe layered composite material are based on the theory of

  9. Discretionary Time of Chinese College Students: Activities and Impact of SARS-Induced Constraints on Choices

    Science.gov (United States)

    Yang, He; Hutchinson, Susan; Zinn, Harry; Watson, Alan

    2011-01-01

    How people make choices about activity engagement during discretionary time is a topic of increasing interest to those studying quality of life issues. Assuming choices are made to maximize individual welfare, several factors are believed to influence these choices. Constraints theory from the leisure research literature suggests these choices are…

  10. A Constraint Satisfaction Neural Network and Heuristic Combined Approach for Concurrent Activities Scheduling

    Institute of Scientific and Technical Information of China (English)

    YAN JiHong(闫纪红); WU Cheng(吴澄)

    2003-01-01

    Scheduling activities in concurrent product development process is of great sig-nificance to shorten development lead time and minimize the cost. Moreover, it can eliminate theunnecessary redesign periods and guarantee that serial activities can be executed as concurrently aspossible. This paper presents a constraint satisfaction neural network and heuristic combined ap-proach for concurrent activities scheduling. In the combined approach, the neural network is usedto obtain a feasible starting time of all the activities based on sequence constraints, the heuris-tic algorithm is used to obtain a feasible solution of the scheduling problem based on resourceconstraints. The feasible scheduling solution is obtained by a gradient optimization function. Sim-ulations have shown that the proposed combined approach is efficient and feasible with respect toconcurrent activities scheduling.

  11. Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

    Science.gov (United States)

    Eckner, James T.; Oh, Youkeun K.; Joshi, Monica S.; Richardson, James K.; Ashton-Miller, James A.

    2015-01-01

    Background Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete's risk of concussion during a collision by attenuating the head's kinematic response after impact. However, the literature reporting the neck's role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. Hypotheses In each anatomic plane, peak linear velocity (DV) and peak angular velocity (Dv) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, DV and Dv will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Study Design Descriptive laboratory study. Methods Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes' heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head DV and Dv. Results Greater isometric neck strength and anticipatory activation were independently associated with decreased head DV and Dv after impulsive loading across all planes of motion (all P\\.001). Inverse relationships between neck strength and head DV and Dv presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. Conclusion In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation (“bracing for impact”) can reduce the magnitude of the head's kinematic response. Future studies should determine whether neck strength contributes to the observed sex and

  12. Kinematical Quantization

    CERN Document Server

    Anderson, Edward

    2016-01-01

    We consider here kinematical quantization: a first and often overlooked step in quantization procedures. $\\mathbb{R}$, $\\mathbb{R}_+$ and the interval are considered, as well as direct (Cartesian) products thereof. Some simple minisuperspace models, and mode by mode consideration of slightly inhomogeneous cosmology, have indefinite signature versions of such kinematical quantizations. The examples in the current paper build in particular toward the case of vacuum $\\mathbb{S}^3$ slightly inhomogeneous cosmology's mode configuration space, which is mathematically a finite time interval slab of Minkowski spacetime.

  13. State-based decoding of hand and finger kinematics using neuronal ensemble and LFP activity during dexterous reach-to-grasp movements.

    Science.gov (United States)

    Aggarwal, Vikram; Mollazadeh, Mohsen; Davidson, Adam G; Schieber, Marc H; Thakor, Nitish V

    2013-06-01

    The performance of brain-machine interfaces (BMIs) that continuously control upper limb neuroprostheses may benefit from distinguishing periods of posture and movement so as to prevent inappropriate movement of the prosthesis. Few studies, however, have investigated how decoding behavioral states and detecting the transitions between posture and movement could be used autonomously to trigger a kinematic decoder. We recorded simultaneous neuronal ensemble and local field potential (LFP) activity from microelectrode arrays in primary motor cortex (M1) and dorsal (PMd) and ventral (PMv) premotor areas of two male rhesus monkeys performing a center-out reach-and-grasp task, while upper limb kinematics were tracked with a motion capture system with markers on the dorsal aspect of the forearm, hand, and fingers. A state decoder was trained to distinguish four behavioral states (baseline, reaction, movement, hold), while a kinematic decoder was trained to continuously decode hand end point position and 18 joint angles of the wrist and fingers. LFP amplitude most accurately predicted transition into the reaction (62%) and movement (73%) states, while spikes most accurately decoded arm, hand, and finger kinematics during movement. Using an LFP-based state decoder to trigger a spike-based kinematic decoder [r = 0.72, root mean squared error (RMSE) = 0.15] significantly improved decoding of reach-to-grasp movements from baseline to final hold, compared with either a spike-based state decoder combined with a spike-based kinematic decoder (r = 0.70, RMSE = 0.17) or a spike-based kinematic decoder alone (r = 0.67, RMSE = 0.17). Combining LFP-based state decoding with spike-based kinematic decoding may be a valuable step toward the realization of BMI control of a multifingered neuroprosthesis performing dexterous manipulation.

  14. Kinematics and Dynamics of a New 16 DOF Humanoid Biped Robot with Active Toe Joint

    Directory of Open Access Journals (Sweden)

    C. Hernández-Santos

    2012-11-01

    Full Text Available Humanoid biped robots are typically complex in design, having numerous Degrees-of-Freedom (DOF due to the ambitious goal of mimicking the human gait. The paper proposes a new architecture for a biped robot with seven DOF per each leg and one DOF corresponding to the toe joint. Furthermore, this work presents close equations for the forward and inverse kinematics by dividing the walking gait into the Sagittal and Frontal planes. This paper explains the mathematical model of the dynamics equations for the legs into the Sagittal and Frontal planes by further applying the principle of Lagrangian dynamics. Finally, a control approach using a PD control law with gravity compensation was recurred in order to control the desired trajectories and finding the required torque by the joints. The paper contains several simulations and numerical examples to prove the analytical results, using SimMechanics of MATLAB toolbox and SolidWorks to verify the analytical results.

  15. Barefoot vs common footwear: A systematic review of the kinematic, kinetic and muscle activity differences during walking.

    Science.gov (United States)

    Franklin, Simon; Grey, Michael J; Heneghan, Nicola; Bowen, Laura; Li, François-Xavier

    2015-09-01

    Habitual footwear use has been reported to influence foot structure with an acute exposure being shown to alter foot position and mechanics. The foot is highly specialised thus these changes in structure/position could influence functionality. This review aims to investigate the effect of footwear on gait, specifically focussing on studies that have assessed kinematics, kinetics and muscle activity between walking barefoot and in common footwear. In line with PRISMA and published guidelines, a literature search was completed across six databases comprising Medline, EMBASE, Scopus, AMED, Cochrane Library and Web of Science. Fifteen of 466 articles met the predetermined inclusion criteria and were included in the review. All articles were assessed for methodological quality using a modified assessment tool based on the STROBE statement for reporting observational studies and the CASP appraisal tool. Walking barefoot enables increased forefoot spreading under load and habitual barefoot walkers have anatomically wider feet. Spatial-temporal differences including, reduced step/stride length and increased cadence, are observed when barefoot. Flatter foot placement, increased knee flexion and a reduced peak vertical ground reaction force at initial contact are also reported. Habitual barefoot walkers exhibit lower peak plantar pressures and pressure impulses, whereas peak plantar pressures are increased in the habitually shod wearer walking barefoot. Footwear particularly affects the kinematics and kinetics of gait acutely and chronically. Little research has been completed in older age populations (50+ years) and thus further research is required to better understand the effect of footwear on walking across the lifespan.

  16. Determining Inclinations of Active Galactic Nuclei Via Their Narrow-Line Region Kinematics - II. Correlation With Observed Properties

    CERN Document Server

    Fischer, T C; Kraemer, S B; Schmitt, H R; Turner, T J

    2014-01-01

    Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally unknown. By determining the inclinations and geometries of nearby Seyfert galaxies using the kinematics of their narrow-line regions (NLRs), and comparing them with observed properties, we find strong correlations between inclination and total hydrogen column density, infrared color, and H-beta full-width at half maximum (FWHM). These correlations provide evidence that the orientation of AGN with respect to our line of sight affects how we perceive them, beyond the Seyfert type dichotomy. They can also be used to constrain 3D models of AGN components such as the broad-line region and torus. Additionally, we find weak correlations between AGN luminosity and several modeled NLR parameters, which suggests that the NLR geometry and kinematics are dependent to some degree on the ...

  17. Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

    Science.gov (United States)

    Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

    2016-06-14

    Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates.

  18. Rational kinematics

    CERN Document Server

    Angeles, Jorge

    1988-01-01

    A rational study of kinematics is a treatment of the subject based on invariants, i.e., quantities that remain essentially unchanged under a change of observer. An observer is understood to be a reference frame supplied with a clock (Truesdell 1966). This study will therefore include an introduction to invariants. The language of these is tensor analysis and multilinear algebra, both of which share many isomorphic relations, These subjects are treated in full detail in Ericksen (1960) and Bowen and Wang (1976), and hence will not be included here. Only a short account of notation and definitions will be presented. Moreover, definitions and basic concepts pertaining to the kinematics of rigid bodies will be also included. Although the kinematics of rigid bodies can be regarded as a particular case of the kinematics of continua, the former deserves attention on its own merits for several reasons. One of these is that it describes locally the motions undergone by continua. Another reason is that a whole area of ...

  19. Optimal operation of batch processes via the tracking of active constraints.

    Science.gov (United States)

    Bonvin, Dominique; Srinivasan, Bala

    2003-01-01

    This paper presents a new measurement-based optimization framework for batch processes whereby optimal operation can be achieved via the tracking of active constraints. It is shown that, under mild assumptions and to a first-order approximation, tracking the necessary conditions of optimality is equivalent to tracking active constraints (both during the batch and at the end of the batch). Thus the optimal input trajectories can be adjusted using measurements without the use of a model of the process. When only batch-end measurements are available, the proposed method leads itself to an efficient batch-to-batch optimization scheme. The approach is illustrated via the simulation of a semibatch reactor under uncertainty.

  20. Control law design to meet constraints using SYNPAC-synthesis package for active controls

    Science.gov (United States)

    Adams, W. M., Jr.; Tiffany, S. H.

    1982-01-01

    Major features of SYNPAC (Synthesis Package for Active Controls) are described. SYNPAC employs constrained optimization techniques which allow explicit inclusion of design criteria (constraints) in the control law design process. Interrelationships are indicated between this constrained optimization approach, classical and linear quadratic Gaussian design techniques. Results are presented that were obtained by applying SYNPAC to the design of a combined stability augmentation/gust load alleviation control law for the DAST ARW-2.

  1. Kinematics of the anemic cluster galaxy NGC 4548 Is stripping still active?

    CERN Document Server

    Vollmer, B; Boselli, A; Balkowski, C; Duschl, W J

    1999-01-01

    We present new HI (20" resolution) and CO observations of NGC 4548, an anemic galaxy in the Virgo cluster. The atomic gas distribution shows a ring structure which is distorted at the northern edge. The overall rotation curve is derived with a tilted ring model. We compare our rotation curve with previous ones and discuss the differences. The velocity field of the CO pointings fit very well with the one of the atomic gas where they overlap. The CO emission permits to extend the rotation curve towards the galaxy centre. The molecular fraction is derived for the inner 120" x 120" centered on the galaxy. We compare the HI and CO emission to H_alpha line and optical blue emission maps. The bar in the centre favors star formation at the outer end of the bar. The HI intensity distribution and velocity field of the northern perturbation are deprojected with the help of a first order kinematical model. They are discussed in the framework of warps. It is concluded that the scenario of ram pressure stripping responsibl...

  2. Kinematics and excitation of the nuclear spiral in the active galaxy Arp 102B

    CERN Document Server

    Couto, Guilherme S; Axon, David J; Robinson, Andrew; Kharb, Preeti; Riffel, Rogemar A

    2013-01-01

    We present a two-dimensional analysis of the gaseous excitation and kinematics of the inner 2.5 x 1.7 kpc^2 of the LINER/Seyfert 1 galaxy Arp 102B, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of 250 pc. Emission-line flux maps show the same two-armed nuclear spiral we have discovered in previous observations with the HST-ACS camera. One arm reaches 1 kpc to the east and the other 500 pc to the west, with a 8.4 GHz VLA bent radio jet correlating with the former. The gas density is highest (500 - 900 cm^(-3)) at the nucleus and in the northern border of the east arm, at a region where the radio jet seems to be deflected. Channel maps show blueshifts but also some redshifts at the eastern arm and jet location which can be interpreted as originated in the front and back walls of an outflow pushed by the radio jet, suggesting also that the outflow is launched close to the plane of the sky. We estimate a mass outflow rate along the ea...

  3. A high-resolution spectroscopic survey of late-type stars: chromospheric activity, rotation, kinematics, and age

    CERN Document Server

    Lopez-Santiago, J; Galvez-Ortiz, M C; Crespo-Chacon, I; Martinez-Arnaiz, R M; Fernandez-Figueroa, M J; De Castro, E; Cornide, M

    2010-01-01

    Aims: We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood which may be used to investigate different aspects of the formation and evolution of the solar neighborhood in terms of kinematics and stellar formation history. The data have already been used by us in several studies. With this paper, we make all these data accessible to the scientific community for future studies on different topics. Methods: We performed spectroscopic observations with echelle spectrographs to cover the entirety of the optical spectral range simultaneously. Standard data reduction was performed with the IRAF ECHELLE package. We applied the spectral subtraction technique to reveal chromospheric emission in the stars of the sample. The equivalent width of chromospheric emission lines was measured in the subtracted spectra and then converted to fluxes using equivalent width-flux relationships. Radial and rotational velocities were determined by the cross-co...

  4. Active semi-supervised community detection based on must-link and cannot-link constraints.

    Directory of Open Access Journals (Sweden)

    Jianjun Cheng

    Full Text Available Community structure detection is of great importance because it can help in discovering the relationship between the function and the topology structure of a network. Many community detection algorithms have been proposed, but how to incorporate the prior knowledge in the detection process remains a challenging problem. In this paper, we propose a semi-supervised community detection algorithm, which makes full utilization of the must-link and cannot-link constraints to guide the process of community detection and thereby extracts high-quality community structures from networks. To acquire the high-quality must-link and cannot-link constraints, we also propose a semi-supervised component generation algorithm based on active learning, which actively selects nodes with maximum utility for the proposed semi-supervised community detection algorithm step by step, and then generates the must-link and cannot-link constraints by accessing a noiseless oracle. Extensive experiments were carried out, and the experimental results show that the introduction of active learning into the problem of community detection makes a success. Our proposed method can extract high-quality community structures from networks, and significantly outperforms other comparison methods.

  5. Influence of Hatha yoga on physical activity constraints, physical fitness, and body image of breast cancer survivors: a pilot study.

    Science.gov (United States)

    Van Puymbroeck, Marieke; Schmid, Arlene; Shinew, Kimberly J; Hsieh, Pei-Chun

    2011-01-01

    Breast cancer survivors often experience changes in their perception of their bodies following surgical treatment. These changes in body image may increase self-consciousness and perceptions of physical activity constraints and reduce participation in physical activity. While the number of studies examining different types of yoga targeting women with breast cancer has increased, studies thus far have not studied the influence that Hatha yoga has on body image and physical activity constraints. The objective of this study was to explore the changes that occur in breast cancer survivors in terms of body image, perceived constraints, and physical fitness following an 8-week Hatha yoga intervention. This study used a nonrandomized two-group pilot study, comparing an 8-week Hatha yoga intervention with a light exercise group, both designed for women who were at least nine months post-treatment for breast cancer. Both quantitative and qualitative data were collected in the areas of body image, physical activity constraints, and physical fitness. Findings indicated that quantitatively, yoga participants experienced reductions in physical activity constraints and improvements in lower- and upper-body strength and flexibility, while control participants experienced improvements in abdominal strength and lower-body strength. Qualitative findings support changes in body image, physical activity constraints, and physical fitness for the participants in the yoga group. In conclusion, Hatha yoga may reduce constraints to physical activity and improve fitness in breast cancer survivors. More research is needed to explore the relationship between Hatha yoga and improvements in body image.

  6. Interrelationship of motivation for and perceived constraints to physical activity participation and the well-being of senior center participants

    Science.gov (United States)

    Motoko Miyake; Ellen Rodgers

    2009-01-01

    This study investigated the relationship of motivation for and perceived constraints to physical activity (PA) participation and the well-being of senior center participants. A survey instrument made up of modified versions of the Sport Motivation and Perceived Constraints Scales, the Life Satisfaction Index-Z, and the Geriatric Depression Scale was administered at the...

  7. Robust fault-tolerant H∞ control of active suspension systems with finite-frequency constraint

    Science.gov (United States)

    Wang, Rongrong; Jing, Hui; Karimi, Hamid Reza; Chen, Nan

    2015-10-01

    In this paper, the robust fault-tolerant (FT) H∞ control problem of active suspension systems with finite-frequency constraint is investigated. A full-car model is employed in the controller design such that the heave, pitch and roll motions can be simultaneously controlled. Both the actuator faults and external disturbances are considered in the controller synthesis. As the human body is more sensitive to the vertical vibration in 4-8 Hz, robust H∞ control with this finite-frequency constraint is designed. Other performances such as suspension deflection and actuator saturation are also considered. As some of the states such as the sprung mass pitch and roll angles are hard to measure, a robust H∞ dynamic output-feedback controller with fault tolerant ability is proposed. Simulation results show the performance of the proposed controller.

  8. EXAMINATION OF CONSTRAINTS ON PHYSICAL ACTIVITY PROGRAMS PARTICIPATION TO INDIVIDUALS WITH AUTISM

    Directory of Open Access Journals (Sweden)

    İsmail AYDIN

    2014-07-01

    Full Text Available The aim of this study was to examine perceptions of constraints on physical activity participation among people with autism. This qualitative study was conducted on 9 different family of people with autism who participating in physical activity program. The data were collected by using semi - structured interview form. The literature review was done with the purpose of preparing the interview questions and creating conceptual framework. A semi - structured form was developed that consists of 7 items and 7 themes. The data were collected by using face to face interview methods. The descriptive analyses were used to analyze the collected data. The analysis indicated that the most important co nstraints were the economical factors on physical activity participation. The most important reason for this occurring was the lack of such programs in the public schools or in institutions. In addition to, this services carried by only the private sector was the other important factor that affected this reason. Analysis also revealed that central government policies of individuals with autism was insufficient for the participation in such programs in the state (government contact and also does not meet t heir needs. As a result, economic difficulties of individuals with autism to participate in physical activity programs was considered the most important constraints. However, it can be concluded that state (government policies were inadequate that in the social life of individuals with autism use their potential in educational activities that support participation in physical activity programs .

  9. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury An explorative study

    NARCIS (Netherlands)

    Kloosterman, Marieke G. M.; Snoek, Govert J.; Kouwenhoven, Mirjam; Nene, Anand V.; Jannink, Michiel J. A.

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation), however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown We conducted a cross-sectional explorative

  10. Effects of a posture-sensing air seat device (PSASD) on kinematics and trunk muscle activity during continuous computer work.

    Science.gov (United States)

    Park, Se-Yeon; Yoo, Won-Gyu

    2011-01-01

    The prevalence and incidence of musculoskeletal disorders is high with computer workers, and poor sitting posture can be considered a factor contributing to low back discomfort. In the clinical literature, maintaining a neutral spinal curvature has been considered an optimal sitting posture. This study investigated the flexion and lateral flexion of trunk movements and trunk muscle activity during computer work with and without a posture-sensing air seat device (PSASD). By sensing a certain amount of increased pressure over the baseline, posture-related visual feedback was given to participants through the PSASD. Eleven regular computer workers participated in this study. PSASD had the function of alerting the subject to their poor posture by using visual feedback. Subjects performed 20 min of computer work with and without a PSASD. Surface electromyography was used to measure the activity of the erector spine and internal abdominal oblique. Kinematic data were obtained using an electrogoniometer. The results showed that the mean of trunk flexion and lateral flexion was significantly reduced with PSASD. The activity of the erector spine and internal oblique was significantly higher with the PSASD than without. Our findings indicated that the PSASD helps to prevent habitual poor posture by maintaining an erect sitting posture during prolonged computer work.

  11. The effect of trunk rotation during shoulder exercises on the activity of the scapular muscle and scapular kinematics.

    Science.gov (United States)

    Yamauchi, Taishi; Hasegawa, Satoshi; Matsumura, Aoi; Nakamura, Masatoshi; Ibuki, Satoko; Ichihashi, Noriaki

    2015-06-01

    In patients with shoulder disease, kinetic chain exercises including hip or trunk movement are recommended. However, the actual muscle activation and scapular kinematics of these exercises are not known. The purpose of this study was to examine the effect of trunk rotation on shoulder exercises that are devised to improve scapular function. Thirteen healthy young men participated in this study. Scaption, external rotation in the first and second positions, and prone scapular retraction at 45°, 90°, and 145° of shoulder abduction were performed with and without trunk rotation. Electromyography was used to assess the scapular muscle activity of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA), and electromagnetic motion capture was used to assess scapular motion. The muscle activity ratio, which is the activity of the UT to the MT, LT, and SA, was calculated. These data were compared between 2 conditions (with and without trunk rotation) for each exercise. Adding trunk rotation to scaption, the first external rotation, and the second external rotation significantly increased scapular external rotation and posterior tilt, and all 3 exercises increased LT activation. In addition, trunk rotation with scapular retraction at 90° and 145° of shoulder abduction significantly decreased the UT/LT ratio. Our findings suggest that shoulder exercises with trunk rotation in this study may be effective in patients who have difficulty in enhancing LT activity and suppressing excessive activation of the UT or in cases in which a decreased scapular external rotation or posterior tilt is observed. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  12. The generalized Hill model: A kinematic approach towards active muscle contraction

    Science.gov (United States)

    Göktepe, Serdar; Menzel, Andreas; Kuhl, Ellen

    2014-12-01

    Excitation-contraction coupling is the physiological process of converting an electrical stimulus into a mechanical response. In muscle, the electrical stimulus is an action potential and the mechanical response is active contraction. The classical Hill model characterizes muscle contraction though one contractile element, activated by electrical excitation, and two non-linear springs, one in series and one in parallel. This rheology translates into an additive decomposition of the total stress into a passive and an active part. Here we supplement this additive decomposition of the stress by a multiplicative decomposition of the deformation gradient into a passive and an active part. We generalize the one-dimensional Hill model to the three-dimensional setting and constitutively define the passive stress as a function of the total deformation gradient and the active stress as a function of both the total deformation gradient and its active part. We show that this novel approach combines the features of both the classical stress-based Hill model and the recent active-strain models. While the notion of active stress is rather phenomenological in nature, active strain is micro-structurally motivated, physically measurable, and straightforward to calibrate. We demonstrate that our model is capable of simulating excitation-contraction coupling in cardiac muscle with its characteristic features of wall thickening, apical lift, and ventricular torsion.

  13. Constraint-induced movement therapy improves upper limb activity and participation in hemiplegic cerebral palsy: a systematic review

    Directory of Open Access Journals (Sweden)

    Hsiu-Ching Chiu

    2016-07-01

    Full Text Available Questions: Does constraint-induced movement therapy improve activity and participation in children with hemiplegic cerebral palsy? Does it improve activity and participation more than the same dose of upper limb therapy without restraint? Is the effect of constraint-induced movement therapy related to the duration of intervention or the age of the children? Design: Systematic review of randomised trials with meta-analysis. Participants: Children with hemiplegic cerebral palsy with any level of motor disability. Intervention: The experimental group received constraint-induced movement therapy (defined as restraint of the less affected upper limb during supervised activity practice of the more affected upper limb. The control group received no intervention, sham intervention, or the same dose of upper limb therapy. Outcome measures: Measures of upper limb activity and participation were used in the analysis. Results: Constraint-induced movement therapy was more effective than no/sham intervention in terms of upper limb activity (SMD 0.63, 95% CI 0.20 to 1.06 and participation (SMD 1.21, 95% CI 0.41 to 2.02. However, constraint-induced movement therapy was no better than the same dose of upper limb therapy without restraint either in terms of upper limb activity (SMD 0.05, 95% CI –0.21 to 0.32 or participation (SMD –0.02, 95% CI –0.34 to 0.31. The effect of constraint-induced movement therapy was not related to the duration of intervention or the age of the children. Conclusions: This review suggests that constraint-induced movement therapy is more effective than no intervention, but no more effective than the same dose of upper limb practice without restraint. Registration: PROSPERO CRD42015024665. [Chiu H-C, Ada L (2016 Constraint-induced movement therapy improves upper limb activity and participation in hemiplegic cerebral palsy: a systematic review. Journal of Physiotherapy 62: 130–137

  14. Constraints of recreational sport participation: measurement invariance and latent mean differences across sex and physical activity status.

    Science.gov (United States)

    Liu, Jing Dong; Chung, Pak Kwong; Chen, Wing Ping

    2014-10-01

    The purpose of the current study was to (a) examine the measurement invariance of the Constraint Scale of Sport Participation across sex and physical activity status among the undergraduate students (N = 630) in Hong Kong and (b) compare the latent mean differences across groups. Measurement invariance of the Constraint Scale of Sport Participation across sex of and physical activity status of the participants was examined first. With receiving support on the measurement invariance across groups, latent mean differences of the scores across groups were examined. Multi-group confirmatory factor analysis revealed that the configural, metric, scalar, and structural invariance of the scale was supported across groups. The results of latent mean differences suggested that the women reported significantly higher constraints on time, partner, psychology, knowledge, and interest than the men. The physically inactive participants reported significantly higher scores on all constraints except for accessibility than the physically active participants.

  15. A conceptual framework for understanding thermal constraints on ectotherm activity with implications for predicting responses to global change.

    Science.gov (United States)

    Gunderson, Alex R; Leal, Manuel

    2015-12-09

    Activity budgets influence the expression of life history traits as well as population dynamics. For ectotherms, a major constraint on activity is environmental temperature. Nonetheless, we currently lack a comprehensive conceptual framework for understanding thermal constraints on activity, which hinders our ability to rigorously apply activity data to answer ecological and evolutionary questions. Here, we integrate multiple aspects of temperature-dependent activity into a single unified framework that has general applicability. We also provide examples of the implementation of this framework to address fundamental questions in ecology relating to climate change vulnerability and species' distributions using empirical data from a tropical lizard.

  16. Lower Extremity Muscle Activation and Kinematics of Catchers When Throwing Using Various Squatting and Throwing Postures

    Directory of Open Access Journals (Sweden)

    Yi-Chien Peng, Kuo-Cheng Lo, Lin-Hwa Wang

    2015-09-01

    Full Text Available This study investigated the differences in joint motions and muscle activities of the lower extremities involved in various squatting postures. The motion capture system with thirty-one reflective markers attached on participants was used for motion data collection. The electromyography system was applied over the quadriceps, biceps femoris, tibialis anterior, and gastrocnemius muscles of the pivot and stride leg. The joint extension and flexion in wide squatting are greater than in general squatting (p = 0.005. Knee joint extension and flexion in general squatting are significantly greater than in wide squatting (p = 0.001. The adduction and abduction of the hip joint in stride passing are significantly greater than in step squatting (p = 0.000. Furthermore, the adduction and abduction of the knee joint in stride passing are also significantly greater than in step squatting (p = 0.000. When stride passing is performed, the muscle activation of the hamstring of the pivot foot in general squatting is significantly greater than in wide squatting (p < 0.05, and this difference continues to the stride period. Most catchers use a general or wide squatting width, exclusive of a narrow one. Therefore, the training design for strengthening the lower extremity muscles should consider the appropriateness of the common squat width to enhance squat-up performance. For lower limb muscle activation, wide squatting requires more active gastrocnemius and tibialis anterior muscles. Baseball players should extend the knee angle of the pivot foot before catching the ball.

  17. Effects of Juvenile Idiopathic Arthritis on Kinematics and Kinetics of the Lower Extremities Call for Consequences in Physical Activities Recommendations

    Directory of Open Access Journals (Sweden)

    M. Hartmann

    2010-01-01

    Full Text Available Juvenile idiopathic arthritis (JIA patients (n=36 with symmetrical polyarticular joint involvement of the lower extremities and healthy controls (n=20 were compared concerning differences in kinematic, kinetic, and spatio-temporal parameters with 3D gait analysis. The aims of this study were to quantify the differences in gait between JIA patients and healthy controls and to provide data for more detailed sport activities recommendations. JIA-patients showed reduced walking speed and step length, strongly anterior tilted pelvis, reduced maximum hip extension, reduced knee extension during single support phase and reduced plantar flexion in push off. Additionally the roll-off procedure of the foot was slightly decelerated. The reduced push off motion in the ankle was confirmed by lower peaks in ankle moment and power. The gait of JIA-patients can be explained as a crouch-like gait with hyperflexion in hip and knee joints and less plantar flexion in the ankle. A preventive mobility workout would be recommendable to reduce these restrictions in the future. Advisable are sports with emphasis on extension in hip, knee, and ankle plantar flexion.

  18. First inverse-kinematics fission measurements in a gaseous active target

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Tajes, C., E-mail: rodriguez@ganil.fr [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bd. Henri Becquerel, 14076 Caen (France); Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Farget, F. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bd. Henri Becquerel, 14076 Caen (France); Acosta, L. [Departamento de Ciencias Integradas, Universidad de Huelva, E-21071 Huelva (Spain); Alvarez-Pol, H. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Babo, M.; Boulay, F. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bd. Henri Becquerel, 14076 Caen (France); Caamaño, M. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Damoy, S. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bd. Henri Becquerel, 14076 Caen (France); Fernández-Domínguez, B. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Galaviz, D. [Centro de Física Nuclear da Universidade de Lisboa, CFNUL, 1649-003 Lisboa (Portugal); Grinyer, G.F.; Grinyer, J. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bd. Henri Becquerel, 14076 Caen (France); Harakeh, M.N. [KVI-CART, University of Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Konczykowski, P. [Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); and others

    2017-02-15

    The fission of a variety of actinides was induced by fusion and transfer reactions between a {sup 238}U beam and {sup 12}C nuclei, in the active target MAYA. The performance of MAYA was studied, as well as its capability to reconstruct the fission-fragment trajectories. Furthermore, a full characterization of the different transfer reactions was achieved, and the populated excitation-energy distributions were investigated as a function of the kinetic energy in the entrance channel. The ratio between transfer- and fusion-induced fission cross-sections was also determined, in order to investigate the competition between both reaction types and its evolution with the incident energy. The experimental results will be discussed with a view to forthcoming radioactive-ion beam facilities, and next-generation active-target setups.

  19. First inverse-kinematics fission measurements in a gaseous active target

    Science.gov (United States)

    Rodríguez-Tajes, C.; Farget, F.; Acosta, L.; Alvarez-Pol, H.; Babo, M.; Boulay, F.; Caamaño, M.; Damoy, S.; Fernández-Domínguez, B.; Galaviz, D.; Grinyer, G. F.; Grinyer, J.; Harakeh, M. N.; Konczykowski, P.; Martel, I.; Pancin, J.; Randisi, G.; Renzi, F.; Roger, T.; Sánchez-Benítez, A. M.; Teubig, P.; Vandebrouck, M.

    2017-02-01

    The fission of a variety of actinides was induced by fusion and transfer reactions between a 238U beam and 12C nuclei, in the active target MAYA. The performance of MAYA was studied, as well as its capability to reconstruct the fission-fragment trajectories. Furthermore, a full characterization of the different transfer reactions was achieved, and the populated excitation-energy distributions were investigated as a function of the kinetic energy in the entrance channel. The ratio between transfer- and fusion-induced fission cross-sections was also determined, in order to investigate the competition between both reaction types and its evolution with the incident energy. The experimental results will be discussed with a view to forthcoming radioactive-ion beam facilities, and next-generation active-target setups.

  20. Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects.

    Science.gov (United States)

    McMillan, Glyn A; Loessin, Vicky; Gray, John R

    2013-09-01

    We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours.

  1. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics

    Directory of Open Access Journals (Sweden)

    Sina Askari, MS

    2013-08-01

    Full Text Available Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI that times FES to robotic treadmill training (RTT. In this study, one group of rats (n = 6 was trained with our FES+RTT system and received stimulation of the ankle flexor (tibialis anterior [TA] muscle timed according to robot-controlled hind-limb position (FES+RTT group; a second group (n = 5 received a similarly patterned stimulation, randomly timed with respect to the rats’ hind-limb movements, while they were in their cages (randomly timed stimulation [RS] group. After 4 wk of training, we tested treadmill stepping ability and compared kinematic measures of hind-limb movement and electromyography (EMG activity in the TA. The FES+RTT group stepped faster and exhibited TA EMG profiles that better matched the applied stimulation profile during training than the RS group. The shape of the EMG profile was assessed by "gamma," a measure that quantified the concentration of EMG activity during the early swing phase of the gait cycle. This gamma measure was 112% higher for the FES+RTT group than for the RS group. The FES+RTT group exhibited burst-to-step latencies that were 41% shorter and correspondingly exhibited a greater tendency to perform ankle flexion movements during stepping than the RS group, as measured by the percentage of time the hind limb was either dragging or in withdrawal. The results from this study support the hypothesis that locomotor training consisting of FES timed to hind-limb movement improves the activation of hind-limb muscle more so than RS alone. Our rodent FES+RTT system can serve as a tool to help further develop this combined therapy to target appropriate neurophysiological changes for locomotor control.

  2. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics.

    Science.gov (United States)

    Askari, Sina; Chao, TeKang; de Leon, Ray D; Won, Deborah S

    2013-01-01

    Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES) to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI) that times FES to robotic treadmill training (RTT). In this study, one group of rats (n = 6) was trained with our FES+RTT system and received stimulation of the ankle flexor (tibialis anterior [TA]) muscle timed according to robot-controlled hind-limb position (FES+RTT group); a second group (n = 5) received a similarly patterned stimulation, randomly timed with respect to the rats' hind-limb movements, while they were in their cages (randomly timed stimulation [RS] group). After 4 wk of training, we tested treadmill stepping ability and compared kinematic measures of hind-limb movement and electromyography (EMG) activity in the TA. The FES+RTT group stepped faster and exhibited TA EMG profiles that better matched the applied stimulation profile during training than the RS group. The shape of the EMG profile was assessed by "gamma," a measure that quantified the concentration of EMG activity during the early swing phase of the gait cycle. This gamma measure was 112% higher for the FES+RTT group than for the RS group. The FES+RTT group exhibited burst-to-step latencies that were 41% shorter and correspondingly exhibited a greater tendency to perform ankle flexion movements during stepping than the RS group, as measured by the percentage of time the hind limb was either dragging or in withdrawal. The results from this study support the hypothesis that locomotor training consisting of FES timed to hind-limb movement improves the activation of hind-limb muscle more so than RS alone. Our rodent FES+RTT system can serve as a tool to help further develop this combined therapy to target appropriate neurophysiological changes for locomotor control.

  3. Ionized gas kinematics of galaxies in the CALIFA survey. I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    NARCIS (Netherlands)

    García-Lorenzo, B.; Márquez, I.; Barrera-Ballesteros, J. K.; Masegosa, J.; Husemann, B.; Falcón-Barroso, J.; Lyubenova, M.; Sánchez, S. F.; Walcher, J.; Mast, D.; García-Benito, R.; Méndez-Abreu, J.; van de Ven, G.; Spekkens, K.; Holmes, L.; Monreal-Ibero, A.; del Olmo, A.; Ziegler, B.; Bland-Hawthorn, J.; Sánchez-Blázquez, P.; Iglesias-Páramo, J.; Aguerri, J. A. L.; Papaderos, P.; Gomes, J. M.; Marino, R. A.; González Delgado, R. M.; Cortijo-Ferrero, C.; López-Sánchez, A. R.; Bekeraitė, S.; Wisotzki, L.; Bomans, D.

    2015-01-01

    Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims: The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies inclu

  4. Effect of ski simulator training on kinematic and muscle activation of the lower extremities.

    Science.gov (United States)

    Moon, Jeheon; Koo, Dohoon; Kim, Kitae; Shin, Insik; Kim, Hyeyoung; Kim, Jinhae

    2015-08-01

    [Purpose] This study aimed to verify the effectiveness of an augmented reality-based ski simulator through analyzing the changes in movement patterns as well as the engagement of major muscles of the lower body. [Subjects] Seven subjects participated in the study. All were national team-level athletes studying at "K" Sports University in Korea who exhibited comparable performance levels and had no record of injuries in the preceding 6 months (Age 23.4 ± 3.8 years; Height 172.6 ± 12.1 cm; Weight 72.3 ± 16.2 kg; Experience 12.3 ± 4.8 years). [Methods] A reality-based ski simulator developed by a Korean manufacturer was used for the study. Three digital video cameras and a wireless electromyography system were used to perform 3-dimensional motion analysis and measure muscle activation level. [Results] Left hip angulation was found to increase as the frequency of the turns increased. Electromyography data revealed that the activation level of the quadriceps group's extension muscles and the biceps femoris group's flexing muscles had a crossing pattern. [Conclusion] Sustained training using an augmented reality-based ski simulator resulted in movements that extended the lower body joints, which is thought to contribute to increasing muscle fatigue.

  5. Accretion/Jet Activity and Narrow [O III] Kinematics in Young Radio Galaxies

    CERN Document Server

    Wu, Qingwen; Humphrey, Andrew

    2009-01-01

    We estimate black hole masses and Eddington ratios for a sample of 81 young radio galaxies (42 CSS +39 GPS). We find that the average black hole (BH) mass of these young radio galaxies is ~8.3, which is less than that of radio loud QSOs and low redshift radio galaxies. The CSS/GPS sources have relatively high Eddington ratios, with an average value of =-0.75, which are similar to those of narrow line Seyfert 1 galaxies (NLS1s). This suggests that young radio galaxies may not only be in the early stages of their radio activity, but also in the early stage of their accretion activity. We find that the young radio galaxies as a class deviate systematically from M_bh-\\sigma relation defined by nearby inactive galaxies, when using [O III] as a surrogate for stellar velocity dispersion, \\sigma_* . We also find that the deviation of the [O III] line width is correlated with the Eddington ratio and sources with Lbol/LEdd~1 have the largest deviations, which are similar to those of radio quiet QSOs/NLS1s (radio jets i...

  6. Constraints on the outer radius of the broad emission line region of active galactic nuclei

    CERN Document Server

    Landt, Hermine; Elvis, Martin; Karovska, Margarita

    2014-01-01

    Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Pa alpha and Pa beta, and find that it scales with the ionising continuum luminosity roughly as expected from photoionisation theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution ...

  7. Effect of limiting ankle-dorsiflexion range of motion on lower extremity kinematics and muscle-activation patterns during a squat.

    Science.gov (United States)

    Macrum, Elisabeth; Bell, David Robert; Boling, Michelle; Lewek, Michael; Padua, Darin

    2012-05-01

    Limitations in gastrocnemius/soleus flexibility that restrict ankle dorsiflexion during dynamic tasks have been reported in individuals with patellofemoral pain (PFP) and are theorized to play a role in its development. To determine the effect of restricted ankle-dorsiflexion range of motion (ROM) on lower extremity kinematics and muscle activity (EMG) during a squat. The authors hypothesized that restricted ankle-dorsiflexion ROM would alter knee kinematics and lower extremity EMG during a squat. Cross-sectional. 30 healthy, recreationally active individuals without a history of lower extremity injury. Each participant performed 7 trials of a double-leg squat under 2 conditions: a no-wedge condition (NW) with the foot flat on the floor and a wedge condition (W) with a 12° forefoot angle to simulate reduced plantar-flexor flexibility. 3-dimensional hip and knee kinematics, medial knee displacement (MKD), and ankle-dorsiflexion angle. EMG of vastus medialis oblique (VMO), vastus lateralis (VL), lateral gastrocnemius (LG), and soleus (SOL). One-way repeated-measures ANOVAs were performed to determine differences between the W and NW conditions. Compared with the NW condition, the wedge produced decreased peak knee flexion (P .05). Altering ankle-dorsiflexion starting position during a double-leg squat resulted in increased knee valgus and MKD, as well as decreased quadriceps activation and increased soleus activation. These changes are similar to those seen in people with PFP.

  8. Decoupled Closed-Form Solution for Humanoid Lower Limb Kinematics

    Directory of Open Access Journals (Sweden)

    Alejandro Said

    2015-01-01

    Full Text Available This paper presents an explicit, omnidirectional, analytical, and decoupled closed-form solution for the lower limb kinematics of the humanoid robot NAO. The paper starts by decoupling the position and orientation analysis from the overall Denavit-Hartenberg (DH transformation matrices. Here, the joint activation sequence for the DH matrices is based on the geometry of a triangle. Furthermore, the implementation of a forward and a reversed kinematic analysis for the support and swing phase equations is developed to avoid matrix inversion. The allocation of constant transformations allows the position and orientation end-coordinate systems to be aligned with each other. Also, the redefinition of the DH transformations and the use of constraints allow decoupling the shared DOF between the legs and the torso. Finally, a geometric approach to avoid the singularities during the walking process is indicated. Numerical data is presented along with an experimental implementation to prove the validity of the analytical results.

  9. Three-dimensional kinematic analysis of active cervical spine motion by using a multifaceted marker device.

    Science.gov (United States)

    Tsunezuka, Hiroaki; Kato, Daishiro; Okada, Satru; Ishihara, Shunta; Shimada, Junichi

    2013-01-01

    Assessing cervical range of motion (CROM) is an important part of the clinical evaluation of patients with conditions such as whiplash syndrome. This study aimed to develop a convenient and accurate system involving multifaceted marker device (MMD)-based assessment of 3-dimensional (3D) dynamic coupled CROM and joint angular velocity. We used an infrared optical tracking system and our newly developed MMD that solved problems such as marker shielding and reflection angle associated with the optical tracking devices and enabled sequential and accurate analysis of the 3D dynamic movement of the polyaxial joint and other structurally complicated joints. The study included 30 asymptomatic young male volunteers (age, 22-27 years). The MMD consisted of 5 surfaces and 5 markers and was attached to the participant's forehead. We measured active CROM (axial rotation, flexion/extension, and lateral bending) and joint angular velocity by the MMD. The MMD was easy to use, safe for patients and operators, could be constructed economically, and generated accurate data such as dynamic coupled CROM and angular velocity.

  10. Kinematic Analysis of Healthy Hips during Weight-Bearing Activities by 3D-to-2D Model-to-Image Registration Technique

    Directory of Open Access Journals (Sweden)

    Daisuke Hara

    2014-01-01

    Full Text Available Dynamic hip kinematics during weight-bearing activities were analyzed for six healthy subjects. Continuous X-ray images of gait, chair-rising, squatting, and twisting were taken using a flat panel X-ray detector. Digitally reconstructed radiographic images were used for 3D-to-2D model-to-image registration technique. The root-mean-square errors associated with tracking the pelvis and femur were less than 0.3 mm and 0.3° for translations and rotations. For gait, chair-rising, and squatting, the maximum hip flexion angles averaged 29.6°, 81.3°, and 102.4°, respectively. The pelvis was tilted anteriorly around 4.4° on average during full gait cycle. For chair-rising and squatting, the maximum absolute value of anterior/posterior pelvic tilt averaged 12.4°/11.7° and 10.7°/10.8°, respectively. Hip flexion peaked on the way of movement due to further anterior pelvic tilt during both chair-rising and squatting. For twisting, the maximum absolute value of hip internal/external rotation averaged 29.2°/30.7°. This study revealed activity dependent kinematics of healthy hip joints with coordinated pelvic and femoral dynamic movements. Kinematics’ data during activities of daily living may provide important insight as to the evaluating kinematics of pathological and reconstructed hips.

  11. Peak Muscle Activation, Joint Kinematics, and Kinetics during Elliptical and Stepping Movement Pattern on a Precor Adaptive Motion Trainer

    Science.gov (United States)

    Rogatzki, Matthew J.; Kernozek, Thomas W.; Willson, John D.; Greany, John F.; Hong, Di-An; Porcari, John P.

    2012-01-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = 0.01), 29% more knee extension (p = 0.003), 101% higher peak…

  12. Peak Muscle Activation, Joint Kinematics, and Kinetics during Elliptical and Stepping Movement Pattern on a Precor Adaptive Motion Trainer

    Science.gov (United States)

    Rogatzki, Matthew J.; Kernozek, Thomas W.; Willson, John D.; Greany, John F.; Hong, Di-An; Porcari, John P.

    2012-01-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = 0.01), 29% more knee extension (p = 0.003), 101% higher peak…

  13. Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?

    Directory of Open Access Journals (Sweden)

    Nicolas Manthevon

    2004-06-01

    Full Text Available In the dense vegetation of temperate or tropical forests, communication processes are constrained by propagation-induced modifications of the transmitted sounds. The presence of leaves, trunks and branches induces important sound reverberation and absorption leading to diminution of the signal energy as well as qualitative modifications. The aim of this paper is to briefly review the different strategies used by birds to manage with these constraints. At the emitter's level, an adapted emission behavior which takes into account both the physical heterogeneities of the forest environment and the temporal variations of the acoustic constraints, is especially useful to control the active space of signaling. The coding of information into acoustic parameters that have different susceptibility to propagation constraints is also of great interest. At the receiver's level, an adaptive reception behavior (listening post and a great tolerance to sound degradation during the decoding process are the keys to an optimal communication process.Na vegetação densa das florestas temperadas ou tropicais, os processos de comunicação são limitados pelas modificações dos sons durante sua propagação. A presença de folhas, troncos e galhos produz uma importante reverberação e absorção do som, provocando uma diminuição da energia do sinal, assim como modificações qualitativas. O objetivo deste artigo é de revisar brevemente as diferentes estratégias usadas por aves para gerenciar essas limitações. Para o emissor, um comportamento de emissão adaptado tanto às heterogeneidades físicas do meio florestal, quanto às variações temporais das exigências acústicas, é particularmente útil para controlar o canal ativo de sinalização. A codificação da informação em parâmetros acústicos com diferentes sensibilidades às exigências de propagação é também de grande valia. Para o receptor, um comportamento adaptado (posto de escuta e uma

  14. X-ray constraints on the fraction of obscured active galactic nuclei at high accretion luminosities

    Science.gov (United States)

    Georgakakis, A.; Salvato, M.; Liu, Z.; Buchner, J.; Brandt, W. N.; Ananna, T. Tasnim; Schulze, A.; Shen, Yue; LaMassa, S.; Nandra, K.; Merloni, A.; McGreer, I. D.

    2017-08-01

    The wide-area XMM-XXL X-ray survey is used to explore the fraction of obscured active galactic nuclei (AGNs) at high accretion luminosities, LX(2-10 keV) ≳ 1044 erg s - 1, and out to redshift z ≈ 1.5. The sample covers an area of about 14 deg2 and provides constraints on the space density of powerful AGNs over a wide range of neutral hydrogen column densities extending beyond the Compton-thick limit, NH ≈ 1024 cm - 2. The fraction of obscured Compton-thin (NH = 1022-1024 cm - 2) AGNs is estimated to be ≈0.35 for luminosities LX(2-10 keV) > 1044 erg s - 1, independent of redshift. For less luminous sources, the fraction of obscured Compton-thin AGNs increases from 0.45 ± 0.10 at z = 0.25 to 0.75 ± 0.05 at z = 1.25. Studies that select AGNs in the infrared via template fits to the observed spectral energy distribution of extragalactic sources estimate space densities at high accretion luminosities consistent with the XMM-XXL constraints. There is no evidence for a large population of AGNs (e.g. heavily obscured) identified in the infrared and missed at X-ray wavelengths. We further explore the mid-infrared colours of XMM-XXL AGNs as a function of accretion luminosity, column density and redshift. The fraction of XMM-XXL sources that lie within the mid-infrared colour wedges defined in the literature to select AGNs is primarily a function of redshift. This fraction increases from about 20-30 per cent at z = 0.25 to about 50-70 per cent at z = 1.5.

  15. Evaluation of the Finis Swimsense® and the Garmin Swim™ activity monitors for swimming performance and stroke kinematics analysis

    Science.gov (United States)

    Mooney, Robert; Corley, Gavin; Godfrey, Alan; Osborough, Conor; ÓLaighin, Gearóid

    2017-01-01

    Aims The study aims were to evaluate the validity of two commercially available swimming activity monitors for quantifying temporal and kinematic swimming variables. Methods Ten national level swimmers (5 male, 5 female; 15.3±1.3years; 164.8±12.9cm; 62.4±11.1kg; 425±66 FINA points) completed a set protocol comprising 1,500m of swimming involving all four competitive swimming strokes. Swimmers wore the Finis Swimsense and the Garmin Swim activity monitors throughout. The devices automatically identified stroke type, swim distance, lap time, stroke count, stroke rate, stroke length and average speed. Video recordings were also obtained and used as a criterion measure to evaluate performance. Results A significant positive correlation was found between the monitors and video for the identification of each of the four swim strokes (Garmin: X2 (3) = 31.292, p<0.05; Finis:X2 (3) = 33.004, p<0.05). No significant differences were found for swim distance measurements. Swimming laps performed in the middle of a swimming interval showed no significant difference from the criterion (Garmin: bias -0.065, 95% confidence intervals -3.828–6.920; Finis bias -0.02, 95% confidence intervals -3.095–3.142). However laps performed at the beginning and end of an interval were not as accurately timed. Additionally, a statistical difference was found for stroke count measurements in all but two occasions (p<0.05). These differences affect the accuracy of stroke rate, stroke length and average speed scores reported by the monitors, as all of these are derived from lap times and stroke counts. Conclusions Both monitors were found to operate with a relatively similar performance level and appear suited for recreational use. However, issues with feature detection accuracy may be related to individual variances in stroke technique. It is reasonable to expect that this level of error would increase when the devices are used by recreational swimmers rather than elite swimmers. Further

  16. Evaluation of the Finis Swimsense® and the Garmin Swim™ activity monitors for swimming performance and stroke kinematics analysis.

    Science.gov (United States)

    Mooney, Robert; Quinlan, Leo R; Corley, Gavin; Godfrey, Alan; Osborough, Conor; ÓLaighin, Gearóid

    2017-01-01

    The study aims were to evaluate the validity of two commercially available swimming activity monitors for quantifying temporal and kinematic swimming variables. Ten national level swimmers (5 male, 5 female; 15.3±1.3years; 164.8±12.9cm; 62.4±11.1kg; 425±66 FINA points) completed a set protocol comprising 1,500m of swimming involving all four competitive swimming strokes. Swimmers wore the Finis Swimsense and the Garmin Swim activity monitors throughout. The devices automatically identified stroke type, swim distance, lap time, stroke count, stroke rate, stroke length and average speed. Video recordings were also obtained and used as a criterion measure to evaluate performance. A significant positive correlation was found between the monitors and video for the identification of each of the four swim strokes (Garmin: X2 (3) = 31.292, pswim distance measurements. Swimming laps performed in the middle of a swimming interval showed no significant difference from the criterion (Garmin: bias -0.065, 95% confidence intervals -3.828-6.920; Finis bias -0.02, 95% confidence intervals -3.095-3.142). However laps performed at the beginning and end of an interval were not as accurately timed. Additionally, a statistical difference was found for stroke count measurements in all but two occasions (p<0.05). These differences affect the accuracy of stroke rate, stroke length and average speed scores reported by the monitors, as all of these are derived from lap times and stroke counts. Both monitors were found to operate with a relatively similar performance level and appear suited for recreational use. However, issues with feature detection accuracy may be related to individual variances in stroke technique. It is reasonable to expect that this level of error would increase when the devices are used by recreational swimmers rather than elite swimmers. Further development to improve accuracy of feature detection algorithms, specifically for lap time and stroke count, would also

  17. Parallel kinematics type, kinematics, and optimal design

    CERN Document Server

    Liu, Xin-Jun

    2014-01-01

    Parallel Kinematics- Type, Kinematics, and Optimal Design presents the results of 15 year's research on parallel mechanisms and parallel kinematics machines. This book covers the systematic classification of parallel mechanisms (PMs) as well as providing a large number of mechanical architectures of PMs available for use in practical applications. It focuses on the kinematic design of parallel robots. One successful application of parallel mechanisms in the field of machine tools, which is also called parallel kinematics machines, has been the emerging trend in advanced machine tools. The book describes not only the main aspects and important topics in parallel kinematics, but also references novel concepts and approaches, i.e. type synthesis based on evolution, performance evaluation and optimization based on screw theory, singularity model taking into account motion and force transmissibility, and others.   This book is intended for researchers, scientists, engineers and postgraduates or above with interes...

  18. The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei II: Kinematic Classifications for the Population at z < 0.1

    CERN Document Server

    Nevin, Rebecca; Müller-Sánchez, Francisco; Barrows, R Scott; Cooper, Michael

    2016-01-01

    We present optical longslit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at $z < 0.1$ in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kpc-scale dual AGNs, and NLR kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using longslit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with longslit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the narrow-line region (NLR) size and luminosity of the AGN NLRs (R$_{\\mathrm{NLR}}\\propto \\; {\\mathrm{L}_{\\mathrm{[OIII]}}}^{0.21 \\pm 0.05}$), indicating a clumpy two-zone ionization model for t...

  19. The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei. II. Kinematic Classifications for the Population at z < 0.1

    Science.gov (United States)

    Nevin, R.; Comerford, J.; Müller-Sánchez, F.; Barrows, R.; Cooper, M.

    2016-11-01

    We present optical long-slit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at z < 0.1 in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kiloparsec-scale dual AGNs, and narrow-line region (NLR) kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using long-slit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate-luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with long-slit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the NLR size and luminosity of the AGN NLRs (R {}{NLR}\\propto {L}[{{O} {{III}}]}0.21+/- 0.05), indicating a clumpy two-zone ionization model for the NLR.

  20. Vector bundle constraint for particle swarm optimization and its application to active contour modeling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Active contour modeling (ACM) has been shown to be a powerful method in object boundary extraction. In this paper,a new ACM based on vector bundle constraint for particle swarm optimization (VBCPSO-ACM) is proposed. Different from the traditional.particle swarm optimization (PSO), in the process of velocity update, a vector bundle is predefined for each particle and velocity update of the particle is restricted to its bundle. Applying this idea to ACM, control points on the contour are treated as particles in PSO and the evolution of the contour is driven by the particles. Meanwhile, global searching is shifted to local searching in ACM by decreasing the number of neighbors and inertia. In addition, the addition and deletion of particles on the active contour make this new model possible for representing the real boundaries more precisely. The proposed VBCPSO-ACM can avoid self-intersection during contour evolving and also extract inhomogeneous boundaries. The simulation results proved its great performance in performing contour extraction.

  1. Strong constraint on hadronic models of blazar activity from Fermi and IceCube stacking analysis

    CERN Document Server

    Neronov, A; Ptitsyna, K

    2016-01-01

    High-energy emission from blazars is produced by electrons which are either accelerated directly (the assumption of leptonic models of blazar activity) or produced in interactions of accelerated protons with matter and radiation fields (the assumption of hadronic models). The hadronic models predict that gamma-ray emission is accompanied by neutrino emission with comparable energy flux but with a different spectrum. We derive constraints on the hadronic models of activity of blazars imposed by non-detection of neutrino flux from a population of gamma-ray emitting blazars. We stack the gamma-ray and muon neutrino flux from 749 blazars situated in the declination strip above -5 degrees. Non-detection of neutrino flux from the stacked blazar sample rules out the proton induced cacade models in which the high-energy emission is powered by interactions of shock-accelerated proton beam in the AGN jet with the ambient matter or with the radiation field of the black hole accretion disk. The result remains valid also ...

  2. Binary Active Galactic Nuclei in Stripe 82: Constraints on Synchronized Black Hole Accretion in Major Mergers

    CERN Document Server

    Fu, Hai; Myers, A D; Djorgovski, S G; Yan, Lin

    2015-01-01

    Representing simultaneous black hole accretion during a merger, binary active galactic nuclei (AGNs) could provide valuable observational constraints to models of galaxy mergers and AGN triggering. High-resolution radio interferometer imaging offers a promising method to identify a large and uniform sample of binary AGNs, because it probes a generic feature of nuclear activity and is free from dust obscuration. Our previous search yielded 52 strong candidates of kpc-scale binaries over the 92 deg^2 of the Sloan Digital Sky Survey (SDSS) Stripe 82 area with 2"-resolution Very Large Array (VLA) images. Here we present 0.3"-resolution VLA 6 GHz observations for six candidates that have complete optical spectroscopy. The new data confirm the binary nature of four candidates and identify the other two as line-of-sight projections of radio structures from single AGNs. The four binary AGNs at z ~ 0.1 reside in major mergers with projected separations of 4.2-12 kpc. Optical spectral modeling shows that their hosts ha...

  3. Interactive inverse kinematics for human motion estimation

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome

    2009-01-01

    We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... estimation system uses a single camera to estimate the motion of a human. The results show that inverse kinematics can significantly speed up the estimation process, while retaining a quality comparable to a full pose motion estimation system. Our novelty lies primarily in use of inverse kinematics...... to significantly speed up the particle filtering. It should be stressed that the observation part of the system has not been our focus, and as such is described only from a sense of completeness. With our approach it is possible to construct a robust and computationally efficient system for human motion estimation....

  4. 3D musculo-skeletal finite element analysis of the foot kinematics under muscle activation with and without ankle arthrodesis

    OpenAIRE

    Perrier, Antoine; Bucki, Marek; Luboz, Vincent; Vuillerme, Nicolas; Payan, Yohan

    2015-01-01

    International audience; The choice between arthrodesis and arthroplasty in the context of advanced ankle arthrosis remains a highly disputed topic in the field of foot and ankle surgery. Arthrodesis, however, represents the most popular option. Biomechanical modeling has been widely used to investigate static loading of cadaveric feet as well as consequences of arthrodesis on bony structures. Although foot kinematics has been studied using motion analysis, this approach lacks accuracy in capt...

  5. The Effects of Constraint-Induced Movement Therapy on Activities Important to Independent School Participation of Children with Hemiparesis

    Science.gov (United States)

    Carney, Joan

    2012-01-01

    This study investigated the efficacy of constraint-induced movement therapy (CI therapy) on activities important to school participation in children with hemiparesis. Four children, ages 4-0 to 7-10 participated in an intensive CI therapy program in a clinical setting. Constraining casts were worn 24 hours daily. Therapy was delivered 6 hours…

  6. The Effects of Constraint-Induced Movement Therapy on Activities Important to Independent School Participation of Children with Hemiparesis

    Science.gov (United States)

    Carney, Joan

    2012-01-01

    This study investigated the efficacy of constraint-induced movement therapy (CI therapy) on activities important to school participation in children with hemiparesis. Four children, ages 4-0 to 7-10 participated in an intensive CI therapy program in a clinical setting. Constraining casts were worn 24 hours daily. Therapy was delivered 6 hours…

  7. JFKengine: A Jacobian and Forward Kinematics Generator

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, K.N.

    2003-02-13

    During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific

  8. Kinematics, Dynamics, and the Structure of Physical Theory

    CERN Document Server

    Curiel, Erik

    2016-01-01

    Every physical theory has (at least) two different forms of mathematical equations to represent its target systems: the dynamical (equations of motion) and the kinematical (kinematical constraints). Kinematical constraints are differentiated from equations of motion by the fact that their particular form is fixed once and for all, irrespective of the interactions the system enters into. By contrast, the particular form of a system's equations of motion depends essentially on the particular interaction the system enters into. All contemporary accounts of the structure and semantics of physical theory treat dynamics, i.e., the equations of motion, as the most important feature of a theory for the purposes of its philosophical analysis. I argue to the contrary that it is the kinematical constraints that determine the structure and empirical content of a physical theory in the most important ways: they function as necessary preconditions for the appropriate application of the theory; they differentiate types of p...

  9. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly

    OpenAIRE

    Santos, Fernanda Dutra dos; Teixeira, Adriane Ribeiro

    2014-01-01

    Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The samp...

  10. Effects of posture-related auditory cueing (PAC) program on muscles activities and kinematics of the neck and trunk during computer work.

    Science.gov (United States)

    Yoo, Won-Gyu; Park, Se-Yeon

    2015-01-01

    The etiology of the neck and back discomfort are highly associated with abnormal static posture such as forward head posture and flexed relaxed posture; such postures are regarded as the risk factors for work-related musculoskeletal disorders. Although, various ergonomic chairs and devices have been developed for computer workers, there are few reports of software that can alert users to their posture or work hours. Purpose of the present study was to investigate the difference of kinematics of the neck and trunk segments as well as muscular activation between condition with and without posture related auditory cueing. Twelve male computer workers were recruited in this study. A posture related auditory cueing (PAC) program used a media file that generated postural correction cue at intervals of 300 seconds. Surface electromyography was used to measure the activity of the erector spine and upper trapezius. Kinematic data were obtained using an ultrasonic three dimensional movement analysis system. The results showed that the means of trunk flexion and forward head angle were significantly reduced with PAC. The muscular activity of the erector spine and upper trapezius was significantly higher with the PAC and significantly lower without the PAC. Our findings suggested that the software providing PACs is an ergonomic device with positive effects for preventing habitual poor posture and potential for widespread practical usage.

  11. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly

    Directory of Open Access Journals (Sweden)

    Santos, Fernanda Dutra dos

    2015-01-01

    Full Text Available Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The sample consisted of elderly subjects with hearing loss who did not use hearing aids. Data were collected in two phases. Initially, all participants underwent an audiological assessment and answered the Hearing Handicap Inventory for Elderly (summarized version and the Geriatric Depression Scale. All subjects participated in the selection and hearing aid adaptation processes and became monaural hearing aid users. After 30 days of hearing aid use, they were assessed with the same instruments. The results of the questionnaires before and after hearing aid adaptation were compared. Results The sample consisted of 13 individuals, between 60 and 90 years old (mean 72.85 ± 11.05 years. Data analysis showed that there was significant improvement in social activity constraints (p < 0.001 and in symptoms of depression (p = 0.031. Conclusion Results show that, in the sample studied, unilateral hearing aid adaptation reduced social activity constraints and depression symptoms.

  12. The Effects of Unilateral Adaptation of Hearing Aids on Symptoms of Depression and Social Activity Constraints of Elderly.

    Science.gov (United States)

    Santos, Fernanda Dutra Dos; Teixeira, Adriane Ribeiro

    2015-07-01

    Introduction Hearing loss is one of the most common problems in the elderly population. Besides compromising oral communication, it directly affects social relations and prevents elderly patients from living actively in society, possibly leading to the onset of depression or other conditions. Objective To analyze the effects of unilateral adaptation of hearing aids on symptoms of depression and the social activity constraints of elderly subjects with hearing impairment. Methods The sample consisted of elderly subjects with hearing loss who did not use hearing aids. Data were collected in two phases. Initially, all participants underwent an audiological assessment and answered the Hearing Handicap Inventory for Elderly (summarized version) and the Geriatric Depression Scale. All subjects participated in the selection and hearing aid adaptation processes and became monaural hearing aid users. After 30 days of hearing aid use, they were assessed with the same instruments. The results of the questionnaires before and after hearing aid adaptation were compared. Results The sample consisted of 13 individuals, between 60 and 90 years old (mean 72.85 ± 11.05 years). Data analysis showed that there was significant improvement in social activity constraints (p depression (p = 0.031). Conclusion Results show that, in the sample studied, unilateral hearing aid adaptation reduced social activity constraints and depression symptoms.

  13. Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?

    DEFF Research Database (Denmark)

    Mathevon, Nicolas; Aubin, Thierry; Dabelsteen, Torben

    2004-01-01

    energy as well as qualitative modifications. The aim of this paper is to briefly review the different strategies used by birds to manage with these constraints. At the emitter’s level, an adapted emission behavior which takes into account both the physical heterogeneities of the forest environment...

  14. MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VI. Kinematics Analysis of a Complete Sample of Blazar Jets

    CERN Document Server

    Lister, M L; Homan, D C; Kadler, M; Kellermann, K I; Kovalev, Y Y; Ros, E; Savolainen, T; Zensus, J A

    2009-01-01

    We discuss the jet kinematics of a complete flux-density-limited sample of 135 radio-loud active galactic nuclei (AGN) resulting from a 13 year program to investigate the structure and evolution of parsec-scale jet phenomena. Our analysis is based on new 2 cm Very Long Baseline Array (VLBA) images obtained between 2002 and 2007, but includes our previously published observations made at the same wavelength, and is supplemented by VLBA archive data. In all, we have used 2424 images spanning the years 1994-2007 to study and determine the motions of 526 separate jet features in 127 jets. The data quality and temporal coverage (a median of 15 epochs per source) of this complete AGN jet sample represents a significant advance over previous kinematics surveys. In all but five AGNs, the jets appear one-sided, most likely the result of differential Doppler boosting. In general the observed motions are directed along the jet ridge line, outward from the optically thick core feature. We directly observe changes in spee...

  15. Kinesiology taping does not alter shoulder strength, shoulder proprioception, or scapular kinematics in healthy, physically active subjects and subjects with Subacromial Impingement Syndrome.

    Science.gov (United States)

    Keenan, Karen A; Akins, Jonathan S; Varnell, Michelle; Abt, John; Lovalekar, Mita; Lephart, Scott; Sell, Timothy C

    2017-03-01

    To examine the effect of kinesiology tape (KT) on shoulder strength, proprioception, and scapular kinematics in healthy and Subacromial Impingement Syndrome (SAIS) subjects. Placebo-controlled quasi-experimental study. Research laboratory. A total of 30 physically active subjects participated. Ten healthy subjects with no previous history of shoulder pathology received KT on the dominant shoulder. Twenty subjects with shoulder pain for a minimum of two weeks and presenting with clinical signs of impingement were allotted to receive KT (n = 10) or placebo taping (PT, n = 10) on the involved shoulder. All participants were tested pre- and post-application. Shoulder internal/external rotation (IR/ER) strength was assessed with isokinetic dynamometry (average peak torque/body weight). Shoulder IR/ER proprioception was assessed through threshold to detect passive motion (mean absolute error in degrees). Scapular position at 90° and 120° of shoulder abduction during arm raising/lowering were assessed using a 3D motion analysis system. No significant within group or between group differences were demonstrated for any measure. Taping does not appear to aid/impair shoulder strength, shoulder proprioception, or scapular kinematics. Future research should explore if the effects of KT are time-dependent and similar in other pathologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Inverse Kinematics of Concentric Tube Steerable Needles

    Science.gov (United States)

    Sears, Patrick; Dupont, Pierre E.

    2013-01-01

    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube displacements and needle tip configuration as well as to the multiplicity of solutions as the number of tubes increases. This paper presents a general approach to solving the inverse kinematics problem using a pseudoinverse solution together with gradients of nullspace potential functions to enforce geometric and mechanical constraints. PMID:23685532

  17. Magmatic evolution of Sulawesi (Indonesia): constraints on the Cenozoic geodynamic history of the Sundaland active margin

    Science.gov (United States)

    Polvé, M.; Maury, R. C.; Bellon, H.; Rangin, C.; Priadi, B.; Yuwono, S.; Joron, J. L.; Atmadja, R. Soeria

    1997-04-01

    Tertiary and Quaternary magmatic rocks from West Sulawesi record the complex history of part of the Sundaland margin where subduction and collision have been and are still active. The present study, based on petrographic data, major- and trace-element chemistry and 40K 40Ar dating aims to document the age and chemical characteristics of the magmatic formations from West Sulawesi and to determine the corresponding constraints on the geodynamic evolution of the Sundaland border. The West Sulawesi magmatic province includes the South Arm of Sulawesi (Ujung Pandang area), the western part of Central Sulawesi with the Toraja and Palu areas, and finally, the North Arm, extending from Palu to Manado, which includes the Tolitoli and Manado areas. Paleocene magmatic activity seems to be restricted to an episode of calc-alkaline magmatism in the Ujung Pandang area (61-59 Ma). The major Eocene (50-40 Ma) magmatic event is tholeiitic and is documented in all areas except in Ujung Pandang. It led to the emplacement of tholeiitic pillow-lavas and basaltic dykes of back-arc basin (BAB) affinity. These rocks are potential equivalents to the Celebes Sea basaltic basement. From Oligocene to Miocene, magmatic eruptions produced successively island-arc tholeiitic (IAT) and calc-alkaline (CA) rock series. The youngest IAT activity occurred around 18 Ma in the central part (Palu area) and around 14 Ma in the North Arm (Tolitoli area) while CA magmas were emplaced in the North Arm at ca. 18 Ma (Tolitoli and Manado areas). Typical calc-alkaline activity resumed only in the North Arm (Tolitoli and Manado areas) during the Late Miocene (9 Ma) and is still active in the Manado region. In other areas (Palu, Toraja and Ujung Pandang areas) an important and widespread magmatic event occurred between 13 and 10 Ma and emplaced K-rich magmas, either silica-undersaturated alkali-potassic basalts (AK), ultrapotassic basanites (UK) or shoshonites (SH). K-rich activity continued in the south until

  18. Kinematically Detected Halo Streams

    CERN Document Server

    Smith, Martin C

    2016-01-01

    Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over- densities in velocity-space, which can remain coherent for much longer than spatial over-densities. This chapter reviews a number of studies that have hunted for these accretion relics, both in the nearby solar-neighborhood and the more-distant stellar halo. Many observational surveys have driven this field forwards, from early work with the Hipparcos mission, to contemporary surveys like RAVE & SDSS. This active field continues to flourish, providing many new discoveries, and will be revolutionised as the Gaia mission delivers precise proper motions for a billion stars in our Galaxy.

  19. Cannibalism and activity rate in larval damselflies increase along a latitudinal gradient as a consequence of time constraints.

    Science.gov (United States)

    Sniegula, Szymon; Golab, Maria J; Johansson, Frank

    2017-07-14

    Predation is ubiquitous in nature. One form of predation is cannibalism, which is affected by many factors such as size structure and resource density. However, cannibalism may also be influenced by abiotic factors such as seasonal time constraints. Since time constraints are greater at high latitudes, cannibalism could be stronger at such latitudes, but we know next to nothing about latitudinal variation in cannibalism. In this study, we examined cannibalism and activity in larvae of the damselfly Lestes sponsa along a latitudinal gradient across Europe. We did this by raising larvae from the egg stage at different temperatures and photoperiods corresponding to different latitudes. We found that the more seasonally time-constrained populations in northern latitudes and individuals subjected to greater seasonal time constraints exhibited a higher level of cannibalism. We also found that activity was higher at north latitude conditions, and thus correlated with cannibalism, suggesting that this behaviour mediates higher levels of cannibalism in time-constrained animals. Our results go counter to the classical latitude-predation pattern which predicts higher predation at lower latitudes, since we found that predation was stronger at higher latitudes. The differences in cannibalism might have implications for population dynamics along the latitudinal gradients, but further experiments are needed to explore this.

  20. Kinematic space and wormholes

    Science.gov (United States)

    Zhang, Jian-dong; Chen, Bin

    2017-01-01

    The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincaré disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincaré disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the SL(2,R) leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore, we discuss the fundamental regions in the kinematic space for the BTZ blackhole and multi-boundary wormholes.

  1. Scheduling a maintenance activity under skills constraints to minimize total weighted tardiness and late tasks

    Directory of Open Access Journals (Sweden)

    Djalal Hedjazi

    2015-04-01

    Full Text Available Skill management is a key factor in improving effectiveness of industrial companies, notably their maintenance services. The problem considered in this paper concerns scheduling of maintenance tasks under resource (maintenance teams constraints. This problem is generally known as unrelated parallel machine scheduling. We consider the problem with a both objectives of minimizing total weighted tardiness (TWT and number of tardiness tasks. Our interest is focused particularly on solving this problem under skill constraints, which each resource has a skill level. So, we propose a new efficient heuristic to obtain an approximate solution for this NP-hard problem and demonstrate his effectiveness through computational experiments. This heuristic is designed for implementation in a static maintenance scheduling problem (with unequal release dates, processing times and resource skills, while minimizing objective functions aforementioned.

  2. Kinematics of syn- and post-exhumational shear zones at Lago di Cignana (Western Alps, Italy): constraints on the exhumation of Zermatt-Saas (ultra)high-pressure rocks and deformation along the Combin Fault and Dent Blanche Basal Thrust

    Science.gov (United States)

    Kirst, Frederik; Leiss, Bernd

    2017-01-01

    Kinematic analyses of shear zones at Lago di Cignana in the Italian Western Alps were used to constrain the structural evolution of units from the Piemont-Ligurian oceanic realm (Zermatt-Saas and Combin zones) and the Adriatic continental margin (Dent Blanche nappe) during Palaeogene syn- and post-exhumational deformation. Exhumation of Zermatt-Saas (U)HP rocks to approximately lower crustal levels at ca. 39 Ma occurred during normal-sense top-(S)E shearing under epidote-amphibolite-facies conditions. Juxtaposition with the overlying Combin zone along the Combin Fault at mid-crustal levels occurred during greenschist-facies normal-sense top-SE shearing at ca. 38 Ma. The scarcity of top-SE kinematic indicators in the hanging wall of the Combin Fault probably resulted from strain localization along the uppermost Zermatt-Saas zone and obliteration by subsequent deformation. A phase of dominant pure shear deformation around 35 Ma affected units in the direct footwall and hanging wall of the Combin Fault. It is interpreted to reflect NW-SE crustal elongation during updoming of the nappe stack as a result of underthrusting of European continental margin units and the onset of continental collision. This phase was partly accompanied and followed by ductile bulk top-NW shearing, especially at higher structural levels, which transitioned into semi-ductile to brittle normal-sense top-NW deformation due to Vanzone phase folding from ca. 32 Ma onwards. Our structural observations suggest that syn-exhumational deformation is partly preserved within units and shear zones exposed at Lago di Cignana but also that the Combin Fault and Dent Blanche Basal Thrust experienced significant post-exhumational deformation reworking and overprinting earlier structures.

  3. Efficient human hand kinematics for manipulation tasks

    OpenAIRE

    Cobos Guzmán, Salvador; Ferre Perez, Manuel; Sanchez-Uran Gonzalez, Miguel Angel; Ortego la Moneda, Javier; Peña, César

    2008-01-01

    This work is focused on obtaining efficient human hand models that are suitable for manipulation tasks. A 24 DoF kinematic model of the human hand is defined to realistic movements. This model is based on the human skeleton. Dynamic and Static constraints have been included in order to improve the movement realism. Two simplified hand models with 9 and 6 DoF have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand post...

  4. Kinematics and dynamics analysis of a novel serial-parallel dynamic simulator

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Bo; Zhang, Lian Dong; Yu, Jingjing [Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao, Hebei (China)

    2016-11-15

    A serial-parallel dynamics simulator based on serial-parallel manipulator is proposed. According to the dynamics simulator motion requirement, the proposed serial-parallel dynamics simulator formed by 3-RRS (active revolute joint-revolute joint-spherical joint) and 3-SPR (Spherical joint-active prismatic joint-revolute joint) PMs adopts the outer and inner layout. By integrating the kinematics, constraint and coupling information of the 3-RRS and 3-SPR PMs into the serial-parallel manipulator, the inverse Jacobian matrix, velocity, and acceleration of the serial-parallel dynamics simulator are studied. Based on the principle of virtual work and the kinematics model, the inverse dynamic model is established. Finally, the workspace of the (3-RRS)+(3-SPR) dynamics simulator is constructed.

  5. About the kinematics of spinning particles

    Energy Technology Data Exchange (ETDEWEB)

    Salesi, G. [Catania Univ. (Italy). Dip. di Fisica]|[INFN, Sezione di Catania (Italy); Recami, E. [Bergamo Univ. (Italy). Facolta` di Ingegneria]|[INFN, Sezione di Milano (Italy)]|[Campinas State Univ., S.P. (Brazil). Dept. of Applied Mathematics

    1995-06-01

    Inserting the correct Lorentz factor into the definition of the 4-velocity v{mu} for spinning particles entails new kinematical properties for v{sup 2}. The well-know constraint (identically true for scalar particles, but entering also the Dirac theory, and assumed a priori in all spinning particle models) P{sub {mu}}v{sup {mu}}=m is here derived in a self-consistent way.

  6. Global-local optimization of flapping kinematics in hovering flight

    KAUST Repository

    Ghommem, Mehdi

    2013-06-01

    The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.

  7. Anticipatory kinematics and muscle activity preceding transitions from level-ground walking to stair ascent and descent.

    Science.gov (United States)

    Peng, Joshua; Fey, Nicholas P; Kuiken, Todd A; Hargrove, Levi J

    2016-02-29

    The majority of fall-related accidents are during stair ambulation-occurring commonly at the top and bottom stairs of each flight, locations in which individuals are transitioning to stairs. Little is known about how individuals adjust their biomechanics in anticipation of walking-stair transitions. We identified the anticipatory stride mechanics of nine able-bodied individuals as they approached transitions from level ground walking to stair ascent and descent. Unlike prior investigations of stair ambulation, we analyzed two consecutive "anticipation" strides preceding the transitions strides to stairs, and tested a comprehensive set of kinematic and electromyographic (EMG) data from both the leading and trailing legs. Subjects completed ten trials of baseline overground walking and ten trials of walking to stair ascent and descent. Deviations relative to baseline were assessed. Significant changes in mechanics and EMG occurred in the earliest anticipation strides analyzed for both ascent and descent transitions. For stair descent, these changes were consistent with observed reductions in walking speed, which occurred in all anticipation strides tested. For stair ascent, subjects maintained their speed until the swing phase of the latest anticipation stride, and changes were found that would normally be observed for decreasing speed. Given the timing and nature of the observed changes, this study has implications for enhancing intent recognition systems and evaluating fall-prone or disabled individuals, by testing their abilities to sense upcoming transitions and decelerate during locomotion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. EFFECT OF POSTURAL CORRECTION WITH DIFFERENT TAPING MATERIALS ON SCAPULAR KINEMATICS AND MYOELECTRIC ACTIVITIES OF SCAPULAR ROTATORS IN SUBACROMIAL IMPINGEMENT SYNDROME A RANDOMIZED PLACEBO-CONTROLLED TRIAL

    Directory of Open Access Journals (Sweden)

    Eman Mohamad Abd Al-Gawad

    2016-06-01

    Full Text Available Background: Rigid and kinesio tapings are commonly used in the rehabilitation of subacromial impingement syndrome (SIS. Yet; the effect of postural correction with the two taping materials in SIS has not been extensively studied. The purpose of the study is to examine the effect of postural correction with two different taping materials on scapular kinematics and electromyography of scapular upward rotators in patients with SIS. Methods: Twenty female patients with SIS participated in this study. Their age ranged from 30-60 years. Participants were randomly assigned into: Group I (Kinesio tape, n=10 and Group II (rigid tape, n=10. Thoracic and scapular taping with posture correction was applied to both groups. Scapular upward rotation at 0˚, 60˚, 90˚ and 120˚ of shoulder elevation and the activity level of the upper fibers of trapezius (UT, lower fibers of trapezius (LT and serratus anterior (SA muscles were measured before and immediately after taping application. Results: Both taping materials significantly increased scapular upward rotation at 60°, 90° and 120° angles (P =.004,.002 and .047 respectively after the application of tape as compared to the before. In addition, significantly greater muscle activity of the LT and SA muscles (P =.027 and 0.05 respectively were demonstrated by the kinesio-taping group as compared to rigid taping group during real taping condition. Conclusion: Both taping materials are effective in restoring scapular kinematics. Furthermore, kinesio taping has a facilitatory effect on the LT and SA muscles. Kinesio taping may be considered an alternative to rigid taping in patients with SIS.

  9. Kinematic Analysis and Experimental Verification on the Locomotion of Gecko

    Institute of Scientific and Technical Information of China (English)

    Woochul Nam; TaeWon Seo; Byungwook Kim; Dongsu Jeon; Kyu-Jin Cho; Jongwon Kim

    2009-01-01

    This paper presents a kinematic analysis of the locomotion of a gecko, and experimental verification of the kinematic model. Kinematic analysis is important for parameter design, dynamic analysis, and optimization in biomimetic robot research. The proposed kinematic analysis can simulate, without iteration, the locomotion of gecko satisfying the constraint conditions that maintain the position of the contacted feet on the surface. So the method has an advantage for analyzing the climbing motion of the quadruped mechanism in a real time application. The kinematic model of a gecko consists of four legs based on 7-degrees of freedom spherical-revolute-spherical joints and two revolute joints in the waist. The motion of the kinematic model is simulated based on measurement data of each joint. The motion of the kinematic model simulates the investigated real gecko's motion by using the experimental results. The analysis solves the forward kinematics by considering the model as a combination of closed and open serial mechanisms under the condition that maintains the contact positions of the attached feet on the ground. The motions of each joint are validated by comparing with the experimental results. In addition to the measured gait, three other gaits are simulated based on the kinematic model. The maximum strides of each gait are calculated by workspace analysis. The result can be used in biomimetic robot design and motion planning.

  10. Kinematic Space and Wormholes

    CERN Document Server

    Zhang, Jian-dong

    2016-01-01

    The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincar\\'e disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincar\\'e disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the $SL(2,\\mathbb{R})$ leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore...

  11. New GPS constraints on active deformation along the Africa-Iberia plate boundary

    Science.gov (United States)

    Koulali, A.; Ouazar, D.; Tahayt, A.; King, R. W.; Vernant, P.; Reilinger, R. E.; McClusky, S.; Mourabit, T.; Davila, J. M.; Amraoui, N.

    2011-08-01

    We use velocities from 65 continuous stations and 31 survey-mode GPS sites as well as kinematic modeling to investigate present day deformation along the Africa-Iberia plate boundary zone in the western Mediterranean region. The GPS velocity field shows southwestward motion of the central part of the Rif Mountains in northern Morocco with respect to Africa varying between 3.5 and 4.0 mm/yr, consistent with prior published results. Stations in the southwestern part of the Betic Mountains of southern Spain move west-southwest with respect to Eurasia (˜ 2-3 mm/yr). The western component of Betics motion is consistent with partial transfer of Nubia-Eurasia plate motion into the southern Betics. The southward component of Betics motion with respect to Iberia is kinematically consistent with south to southwest motion of the Rif Mountains with respect to Africa. We use block modeling, constrained by mapped surface faults and seismicity to estimate the geometry and rates of strain accumulation on plate boundary structures. Our preferred plate boundary geometry includes one block between Iberia and Africa including the SW Betics, Alboran Sea, and central Rif. This geometry provides a good fit to the observed motions, suggesting a wide transpressive boundary in the westernmost Mediterranean, with deformation mainly accommodated by the Gloria-Azores fault system to the West and the Rif-Tell lineament to the East. Block boundaries encompass aspects of earlier interpretations suggesting three main deformation styles: (i) extension along the NE-SW trending Trans-Alboran shear zone, (ii) dextral strike-slip in the Betics corresponding to a well defined E-W seismic lineament, and (iii) right lateral strike-slip motion extending West to the Azores and right-lateral motion with compression extending East along the Algerian Tell. We interpret differential motion in the Rif-Alboran-Betic system to be driven both by surface processes related the Africa-Eurasia oblique convergence and

  12. Kinematics theory and applications

    CERN Document Server

    Wittenburg, Jens

    2016-01-01

    The book deals with kinematics of mechanisms. It focuses on a solid theoretical foundation and on mathematical methods applicable to the solution of problems of very diverse nature. Applications are demonstrated in a large number of fully worked-out problems.  In kinematics a wide variety of mathematical tools is applicable. In this book, wherever possible vector equations are formulated instead of lengthy scalar coordinate equations. The principle of transference is applied to problems of very diverse nature. 15 chapters of the book are devoted to spatial kinematics and three chapters to planar kinematics. In Chapt. 19 nonlinear dynamics equations of motion are formulated for general spatial mechanisms. Nearly one half of the book is dealing with position theory and the other half with motion. The book is intended for use as reference book for researchers and as textbook in advanced courses on kinematics of mechanisms.

  13. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    Science.gov (United States)

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population.

  14. Inclusive distributions near kinematic thresholds

    CERN Document Server

    Gardi, E

    2006-01-01

    The main challenge in computing inclusive cross sections and decay spectra in QCD is posed by kinematic thresholds. The threshold region is characterized by stringent phase-space constraints that are reflected in large perturbative corrections due to soft and collinear radiation as well as large non-perturbative effects. Major progress in addressing this problem was made in recent years by Dressed Gluon Exponentiation (DGE), a formalism that combines Sudakov and renormalon resummation in moment space. DGE has proven effective in extending the range of applicability of perturbation theory well into the threshold region and in identifying the relevant non-perturbative corrections. Here we review the method from a general perspective using examples from deep inelastic structure functions, event-shape distributions, heavy-quark fragmentation and inclusive decay spectra. A special discussion is devoted to the applications of DGE to radiative and semileptonic B decays that have proven valuable for the interpretatio...

  15. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    , under the assumption that the original constraint-based approach has these properties. Practically, as a concrete case study, we have integrated this technique into OFMC, a state-of-the-art model-checker for security protocol analysis, and demonstrated its effectiveness by extensive experimentation. Our......We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...

  16. Advances in robot kinematics

    CERN Document Server

    Khatib, Oussama

    2014-01-01

    The topics addressed in this book cover the whole range of kinematic analysis, synthesis and design and consider robotic systems possessing serial, parallel and cable driven mechanisms. The robotic systems range from being less than fully mobile to kinematically redundant to overconstrained.  The fifty-six contributions report the latest results in robot kinematics with emphasis on emerging areas such as design and control of humanoids or humanoid subsystems. The book is of interest to researchers wanting to bring their knowledge up to date regarding modern topics in one of the basic disciplines in robotics, which relates to the essential property of robots, the motion of mechanisms.

  17. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    Science.gov (United States)

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.

  18. Inverse Kinematics using Quaternions

    DEFF Research Database (Denmark)

    Henriksen, Knud; Erleben, Kenny; Engell-Nørregård, Morten

    In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection....... suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]....

  19. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    Science.gov (United States)

    Chen, Jiunn-Wei; Chi, Hsin-Chang; Lin, Shin-Ted; Liu, C.-P.; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

    2016-05-01

    The transition magnetic moment of a sterile neutrino can give rise to its conversion to an active neutrino through radiative decay or nonstandard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic x-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with low-threshold low-background germanium detectors, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations.

  20. Thermal and barometric constraints on the intrusive and unroofing history of the Black Mountains: Implications for timing, initial dip, and kinematics of detachment faulting in the Death Valley Region, California

    Science.gov (United States)

    Holm, Daniel K.; Snow, J. Kent; Lux, Daniel R.

    1992-06-01

    Unroofing of the Black Mountains, Death Valley, California, has resulted in the exposure of 1.7 Ga crystalline basement, late Precambrian amphibolite facies metasedimentary rocks, and a Tertiary magmatic complex. The 40Ar/39Ar cooling ages, obtained from samples collected across the entire length of the range (>55 km), combined with geobarometric results from synextensional intrusions, provide time-depth constraints on the Miocene intrusive history and extensional unroofing of the Black Mountains. Data from the southeastern Black Mountains and adjacent Greenwater Range suggest unroofing from shallow depths between 9 and 10 Ma. To the northwest in the crystalline core of the range, biotite plateau ages from ˜13 to 6.8 Ma from rocks making up the Death Valley turtlebacks indicate a midcrustal residence (with temperatures >300°C) prior to extensional unroofing. Biotite 40Ar/39Ar ages from both Precambrian basement and Tertiary plutons reveal a diachronous cooling pattern of decreasing ages toward the northwest, subparallel to the regional extension direction. Diachronous cooling was accompanied by dike intrusion which also decreases in age toward the northwest. The cooling age pattern and geobarometric constraints in crystalline rocks of the Black Mountains suggest denudation of 10-15 km along a northwest directed detachment system, consistent with regional reconstructions of Tertiary extension and with unroofing of a northwest deepening crustal section. Mica cooling ages that deviate from the northwest younging trend are consistent with northwestward transport of rocks initially at shallower crustal levels onto deeper levels along splays of the detachment. The well-known Amargosa chaos and perhaps the Badwater turtleback are examples of this "splaying" process. Considering the current distance of the structurally deepest samples away from moderately to steeply east tilted Tertiary strata in the southeastern Black Mountains, these data indicate an average initial

  1. The influence of a semi-reclined seated posture on head and neck kinematics and muscle activity while reading a tablet computer.

    Science.gov (United States)

    Douglas, Ethan C; Gallagher, Kaitlin M

    2017-04-01

    Increased tablet computer usage calls for a proper understanding of potential injury risks from these devices. The purpose of this study was to assess the influence of tablet computer reading postures on head and neck flexion and muscle activity. Nineteen participants completed read a tablet computer in four different postures (standard computer monitor, tablet on a desk, tablet in the lap, semi-reclined with tablet in the lap). Reading the tablet in a semi-reclined trunk posture with the tablet in one's lap increased (p computer monitor (6.39%ROM). Head flexion in the semi-reclined posture (19.7%ROM) and muscle activity (8.88%MVC) were similar to when reading from a standard computer monitor. Despite potentially reducing the gravitational moment produced by the head, the semi-reclined position could still compromise the force capabilities of the neck extensor musculature and result in increased strain on the passive tissues of the spine. Future work should assess how the semi-reclined position influences cervical intervertebral angles and passive tissue properties of the cervical spine. Overall, more research needs to be conducted on thoracic spine kinematics while reading a tablet computer.

  2. America’s Cup Sailing: Effect of Standing Arm-Cranking (“Grinding” Direction on Muscle Activity, Kinematics, and Torque Application

    Directory of Open Access Journals (Sweden)

    Simon N. Pearson

    2016-06-01

    Full Text Available Grinding is a key physical element in America’s Cup sailing. This study aimed to describe kinematics and muscle activation patterns in relation to torque applied in forward and backward grinding. Ten male America’s Cup sailors (33.6 ± 5.7 years, 97.9 ± 13.4 kg, 186.6 ± 7.4 cm completed forward and backward grinding on a customised grinding ergometer. In forward grinding peak torque (77 Nm occurred at 95° (0° = crank vertically up on the downward section of the rotation at the end of shoulder flexion and elbow extension. Backward grinding torque peaked at 35° (69 Nm following the pull action (shoulder extension, elbow flexion across the top of the rotation. During forward grinding, relatively high levels of torque (>50 Nm were maintained through the majority (72% of the cycle, compared to 47% for backward grinding, with sections of low torque corresponding with low numbers of active muscles. Variation in torque was negatively associated with forward grinding performance (r = −0.60; 90% CI −0.88 to −0.02, but positively associated with backward performance (r = 0.48; CI = −0.15 to 0.83. Magnitude and distribution of torque generation differed according to grinding direction and presents an argument for divergent training methods to improve forward and backward grinding performance.

  3. A constrained generalised-α method for coupling rigid parallel chain kinematics and elastic bodies

    OpenAIRE

    Gransden, D.I.; Burkhard Bornemann, P.; Rose, M.; Nitzsche, F.

    2015-01-01

    A problem arises from combining flexible rotorcraft blades with stiffer mechanical links, which form a parallel kinematic chain. This paper introduces a method for solving index-3 differential algebraic equations for coupled stiff and elastic body systems with closed-loop kinematics. Rigid body dynamics and elastic body mechanics are independently described according to convenient mathematical measures. Holonomic constraint equations couple both the parallel chain kinematics and describe the ...

  4. Kinematic Fitting in the Presence of ISR at the ILC

    CERN Document Server

    List, Jenny; List, Benno

    2009-01-01

    Kinematic fitting is a well-established tool to improve jet energy and invariant mass resolutions by fitting the measured values under constraints (e.g. energy conservation). However, in the presence of substantial ISR and Beamstrahlung, naive energy and (longitudinal) momentum constraints fail due to the a priori unknown amount of undetected momentum carried away by collinear photons. It is possible to take care of those two effects and thus obtain significantly higher mass resolutions.

  5. Planet Host Stars: Mass, Age and Kinematics

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We determine the mass, age and kinematics of 51 extra-solar planet host stars. The results are then used to search for signs of connection of the data with metallicity and to investigate the population nature. We find that the increase in mean metallicity with stellar mass is similar to that in normal field stars, so it seems unsuitable to use this relation as a constraint on the theory of planet formation. The age and kinematic distributions seem to favour the metallicity of extra-solar planet host stars being initial. Although the kinematic data of these stars indicate their origin from two populations - the thin and the thick disks, kinematics may not help in the maintenance of the planet around the host. Stars with planets, brown dwarfs or stellar companions are sorted into three groups and re-investigated separately for their formation mechanism. The main results indicate that stars with M2 < 25MJ have [Fe/H] > -0.1 and a wide period range, but there are no other differences.Thus, there does not seem to be any physically distinguishable characteristics among the three star groups.

  6. Mass transfer constraints on the chemical evolution of an active hydrothermal system, Valles caldera, New Mexico

    Science.gov (United States)

    White, A.F.; Chuma, N.J.; Goff, F.

    1992-01-01

    Partial equilibrium conditions occur between fluids and secondary minerals in the Valles hydrothermal system, contained principally in the Tertiary rhyolitic Bandelier Tuff. The mass transfer processes are governed by reactive phase compositions, surface areas, water-rock ratios, reaction rates, and fluid residence times. Experimental dissolution of the vitric phase of the tuff was congruent with respect to Cl in the solid and produced reaction rates which obeyed a general Arrhenius release rate between 250 and 300??C. The 18O differences between reacted and unreacted rock and fluids, and mass balances calculations involving Cl in the glass phase, produced comparable water-rock ratios of unity, confirming the importance of irreversible reaction of the vitric tuff. A fluid residence time of approximately 2 ?? 103 years, determined from fluid reservoir volume and discharge rates, is less than 0.2% of the total age of the hydrothermal system and denotes a geochemically and isotopically open system. Mass transfer calculations generally replicated observed reservoir pH, Pco2, and PO2 conditions, cation concentrations, and the secondary mineral assemblage between 250 and 300??C. The only extraneous component required to maintain observed calcite saturation and high Pco2 pressures was carbon presumably derived from underlying Paleozoic limestones. Phase rule constraints indicate that Cl was the only incompatible aqueous component not controlled by mineral equilibrium. Concentrations of Cl in the reservoir directly reflect mass transport rates as evidenced by correlations between anomalously high Cl concentrations in the fluids and tuff in the Valles caldera relative to other hydrothermal systems in rhyolitic rocks. ?? 1992.

  7. New seismotectonic constraints in the Western Pyrenees: regional activity and aftershock series monitoring.

    Science.gov (United States)

    Ruiz, M.; Gallart, J.; Díaz, J.; González-Cortina, J. M.; Pulgar, J. A.; López, C.

    2003-04-01

    New seismic data from a portable network deployed at the western end of the Pyrenean range reveal a moderate magnitude seismicity, till now poorly constrained by the present-day permanent networks monitoring the area. The westward continuity of the E-W band of seismicity associated to the North Pyrenean Fault, through the Basque Massifs along the Nappe des Marbres, ending up at the Hendaye fault is depicted from our data. This seismicity belt is distributed on a crustal scale, dipping northward to almost 30 km depth. Other groups of seismic events can be related to the southern segment of the Pamplona fault, and to different E-W thrust structures. Following a magnitude 4.1 earthquake on February 21, 2001 SW of Pamplona, another deployment was performed to study the aftershocks series. First determinations showed a small epicentral area of about 4 km2, with events distributed between 1 and 4 km depth. Cross-correlation techniques and relative location of events clusters constrained an epicentral domain 2 Km long and 500m wide, NNO-SSE oriented following the Arakil river course. Focal mechanisms favour an oblique normal fault, with a marked strike-slip component. A new relationship between local magnitude, epicentral distance and total signal duration of the analysed earthquakes was established and used to obtain a value of 0.80 for the b-parameter of the Gutemberg-Richter's law. Distribution of aftershocks magnitudes with time follows the typical power law and gives a value of 1.0 for the Omori's P-parameter. More than 100 aftershocks were accurately located in this high-resolution experiment, 17 of which could only be catalogued by the permanent agencies in the same period, with a much sparser distribution. Our results confirm the importance of using dense portable networks to infer relevant seismotectonic and hazard constraints.

  8. Recognition of Kinematic Joints of 3D Assembly Models Based on Reciprocal Screw Theory

    Directory of Open Access Journals (Sweden)

    Tao Xiong

    2016-01-01

    Full Text Available Reciprocal screw theory is used to recognize the kinematic joints of assemblies restricted by arbitrary combinations of geometry constraints. Kinematic analysis is common for reaching a satisfactory design. If a machine is large and the incidence of redesign frequent is high, then it becomes imperative to have fast analysis-redesign-reanalysis cycles. This work addresses this problem by providing recognition technology for converting a 3D assembly model into a kinematic joint model, which is represented by a graph of parts with kinematic joints among them. The three basic components of the geometric constraints are described in terms of wrench, and it is thus easy to model each common assembly constraint. At the same time, several different types of kinematic joints in practice are presented in terms of twist. For the reciprocal product of a twist and wrench, which is equal to zero, the geometry constraints can be converted into the corresponding kinematic joints as a result. To eliminate completely the redundant components of different geometry constraints that act upon the same part, the specific operation of a matrix space is applied. This ability is useful in supporting the kinematic design of properly constrained assemblies in CAD systems.

  9. Decoupling Kinematic Loops for Real-Time Multibody Dynamic Simulations

    Directory of Open Access Journals (Sweden)

    Omar Mohamed

    2016-01-01

    Full Text Available Earth moving equipment are typically equipped with hydraulic cylinder actuators to perform the designated tasks. Multibody modelling of such systems results in models with kinematic loops that couples the motion variables of the loop bodies. Iterative solutions will be needed to satisfy the loop constraints and the applied constraints, which require evaluation of the constraint Jacobean matrix. The size of the Jacobean matrix and the associated projections depends on the number of motion variables in each kinematic loop. Consequently, the computational cost significantly increases as the number of variables in the kinematic loop increases. Real-time control and hybrid hardware-in-the-loop systems both require efficient and fast computational algorithms. Eliminating the kinematic loops can improve the computational efficiency and effectiveness of the control algorithms. This paper presents an efficient approach to eliminate the coupling due to the cylinder-rod connections and consequently the kinematic loops in the multibody models leading to efficient simulation. The proposed approach calculates the spatial accelerations and inertia forces of the actuator bodies and the interaction forces with other components. The actuator forces are then projected onto the connecting bodies leading to exact dynamics of the system.

  10. An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs

    CERN Document Server

    West, Andrew A; Irwin, Jonathan; Berta-Thompson, Zachory K; Charbonneau, David; Dittmann, Jason; Pineda, J Sebastian

    2015-01-01

    Using spectroscopic observations and photometric light curves of 238 nearby M dwarfs from the MEarth exoplanet transit survey, we examine the relationships between magnetic activity (quantified by H-alpha emission), rotation period, and stellar age. Previous attempts to investigate the relationship between magnetic activity and rotation in these stars were hampered by the limited number of M dwarfs with measured rotation periods (and the fact that vsini measurements probe only rapid rotation). However, the photometric data from MEarth allows us to probe a wide range of rotation periods for hundreds of M dwarf stars (from shorter than than one to longer than 100 days). Over all M spectral types that we probe, we find that the presence of magnetic activity is tied to rotation, including for late-type, fully convective M dwarfs. We also find evidence that the fraction of late-type M dwarfs that are active may be higher at longer rotation periods compared to their early-type counterparts, with several active, lat...

  11. Int\\'egration de contraintes cin\\'ematiques pour le calcul de l'orientation optimis\\'ee de l'axe de l'outil en usinage 5 axes Optimisation of tool axis orientation in 5 axis machining taking into account kinematical constraints

    CERN Document Server

    Lavernhe, Sylvain; Lartigue, Claire; 10.1051/meca:2007064

    2010-01-01

    Apr\\`es avoir d\\'etaill\\'e les principales difficult\\'es li\\'ees \\`a l'usinage 5 axes UGV, nous pr\\'esentons un mod\\`ele de repr\\'esentation des trajectoires 5 axes sous forme surfacique permettant de prendre en compte des contraintes g\\'eom\\'etriques et cin\\'ematiques. Ce mod\\`ele est int\\'egr\\'e dans d'optimisation des trajets 5 axes afin de maximiser la productivit\\'e tout en garantissant la qualit\\'e g\\'eom\\'etrique attendue. Un cas d'application est d\\'etaill\\'e, illustrant la modification de l'orientation de l'axe de l'outil afin d'am\\'eliorer le comportement cin\\'ematique des axes lors du suivi des trajectoires. After presenting the main difficulties related to machining 5 axes machining within the context of HSM, we present a surface model of 5-axis trajectories allowing taking into account geometrical and kinematical constraints. This model is integrated in an optimization scheme in order to maximize the productivity while ensuring the expected geometrical quality. A case of application is detailed, ...

  12. Choice set formation with multiple flexible activities under space-time constraints

    NARCIS (Netherlands)

    Chen, X.; Kwan, M.P.

    2012-01-01

    In classical time geography, an individual travel path is composed of a chain of visits, with each visit being a flexible activity between two fixed activities at two known stations. In reality, individuals tend to carry out trips with much variation and complexity, with multipurpose trips being a p

  13. Physical activity and the recreation opportunity spectrum: differences in important site attributes and perceived constraints

    Science.gov (United States)

    S.A. Wilhelm Stanis; I.E. Schneider; K.J. Sinew; D.J. Chavez; M.C. Vogel

    2009-01-01

    Both legislation and professional organizations call for parks and recreation agencies to address the need for greater physical activity among those living in the United States. A greater understanding of factors that facilitate and constrain physical activity in parks and recreation areas may improve agencies’ ability to address obesity and sedentary lifestyles. This...

  14. The effects on Kinematics and Muscle Activity of Walking in a Robotic Gait Trainer During Zero-Force Control

    NARCIS (Netherlands)

    Asseldonk, van Edwin H.F.; Veneman, Jan F.; Ekkelenkamp, Ralf; Buurke, Jaap H.; Helm, van der Frans C.T.; Kooij, van der Herman

    2008-01-01

    “Assist as needed” control algorithms promote activity of patients during robotic gait training. Implementing these requires a free walking mode of a device, as unassisted motions should not be hindered. The goal of this study was to assess the normality of walking in the free walking mode of the LO

  15. Inverse relationship between the complexity of midfoot kinematics and muscle activation in patients with medial tibial stress syndrome

    DEFF Research Database (Denmark)

    Rathleff, M S; Samani, Afshin; Olesen, C G

    2011-01-01

    Medial tibial stress syndrome is a common overuse injury characterized by pain located on the medial side of the lower leg during weight bearing activities such as gait. The purpose of this study was to apply linear and nonlinear methods to compare the structure of variability of midfoot kinemati...

  16. Transition from collision to subduction in Western Greece: the Katouna-Stamna active fault system and regional kinematics

    Science.gov (United States)

    Pérouse, E.; Sébrier, M.; Braucher, R.; Chamot-Rooke, N.; Bourlès, D.; Briole, P.; Sorel, D.; Dimitrov, D.; Arsenikos, S.

    2016-06-01

    Transition from subduction to collision occurs in Western Greece and is accommodated along the downgoing plate by the Kefalonia right-lateral fault that transfers the Hellenic subduction front to the Apulian collision front. Here we present an active tectonic study of Aitolo-Akarnania (Western Greece) that highlights how such a transition is accommodated in the overriding plate. Based on new multi-scale geomorphic and tectonic observations, we performed an accurate active fault trace mapping in the region, and provide evidence for active normal and left-lateral faulting along the Katouna-Stamna Fault (KSF), a 65-km-long NNW-striking fault system connecting the Amvrakikos Gulf to the Patras Gulf. We further show that the Cenozoic Hellenide thrusts located west of the KSF are no longer active, either in field observation or in GPS data, leading us to propose that the KSF forms the northeastern boundary of a rigid Ionian Islands-Akarnania Block (IAB). Cosmic ray exposure measurements of 10Be and 36Cl were performed on a Quaternary alluvial fan offset along the KSF (~50 m left-lateral offset). A maximum abandonment age of ~12-14 ka for the alluvial fan surface can be determined, giving an estimated KSF minimum geological left-lateral slip rate of ~4 mm year-1, in agreement with high GPS slip rates (~10 mm year-1). Despite this high slip rate, the KSF is characterized by subdued morphological evidence of tectonic activity, a gypsum-breccia bedrock and a low level of seismicity, suggesting a dominantly creeping behavior for this fault. Finally, we discuss how the IAB appears to have been progressively individualized during the Pleistocene (younger than ~1.5 Ma).

  17. A Tale of Two Narrow-Line Regions: Ionization, Kinematics, and Spectral Energy Distributions for a Local Pair of Merging Obscured Active Galaxies

    CERN Document Server

    Hainline, Kevin N; Chen, Chien-Ting; Carroll, Christopher M; Jones, Mackenzie L; Zervos, Alexandros S; Goulding, Andrew D

    2016-01-01

    We explore the gas ionization and kinematics, as well as the optical--IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, $z \\approx 0.04$). Due to the wide separation between these interacting galaxies ($\\sim 23$ kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow line emission in both galaxies is photoionized by an AGN and confirm the existence of a 10-kpc-scale ionization cone in J1816NE, while in J1816SW the AGN narrow-line region is much more compact (1--2 kpc) and relatively undisturbed. Our observations also reveal the presence of ionized gas that nearly spans the entire distance between the galaxies which is likely in a merger-induced tidal stream. In addition, we carry out a spectral an...

  18. Constraint based scheduling for the Goddard Space Flight Center distributed Active Archive Center's data archive and distribution system

    Science.gov (United States)

    Short, Nick, Jr.; Bedet, Jean-Jacques; Bodden, Lee; Boddy, Mark; White, Jim; Beane, John

    1994-01-01

    The Goddard Space Flight Center (GSFC) Distributed Active Archive Center (DAAC) has been operational since October 1, 1993. Its mission is to support the Earth Observing System (EOS) by providing rapid access to EOS data and analysis products, and to test Earth Observing System Data and Information System (EOSDIS) design concepts. One of the challenges is to ensure quick and easy retrieval of any data archived within the DAAC's Data Archive and Distributed System (DADS). Over the 15-year life of EOS project, an estimated several Petabytes (10(exp 15)) of data will be permanently stored. Accessing that amount of information is a formidable task that will require innovative approaches. As a precursor of the full EOS system, the GSFC DAAC with a few Terabits of storage, has implemented a prototype of a constraint-based task and resource scheduler to improve the performance of the DADS. This Honeywell Task and Resource Scheduler (HTRS), developed by Honeywell Technology Center in cooperation the Information Science and Technology Branch/935, the Code X Operations Technology Program, and the GSFC DAAC, makes better use of limited resources, prevents backlog of data, provides information about resources bottlenecks and performance characteristics. The prototype which is developed concurrently with the GSFC Version 0 (V0) DADS, models DADS activities such as ingestion and distribution with priority, precedence, resource requirements (disk and network bandwidth) and temporal constraints. HTRS supports schedule updates, insertions, and retrieval of task information via an Application Program Interface (API). The prototype has demonstrated with a few examples, the substantial advantages of using HTRS over scheduling algorithms such as a First In First Out (FIFO) queue. The kernel scheduling engine for HTRS, called Kronos, has been successfully applied to several other domains such as space shuttle mission scheduling, demand flow manufacturing, and avionics communications

  19. Volunteer kinematics and reaction in lateral emergency maneuver tests

    NARCIS (Netherlands)

    Rooij, L. van; Elrofai, H.B.H.; Philippens, M.M.G.M.; Daanen, H.A.M.

    2013-01-01

    It is important to understand human kinematics and muscle activation patterns in emergency maneuvers for the design of safety systems and for the further development of human models. The objective of this study was to quantify kinematic behavior and muscle activation in simulated steering tests in s

  20. Bayesian kinematic earthquake source models

    Science.gov (United States)

    Minson, S. E.; Simons, M.; Beck, J. L.; Genrich, J. F.; Galetzka, J. E.; Chowdhury, F.; Owen, S. E.; Webb, F.; Comte, D.; Glass, B.; Leiva, C.; Ortega, F. H.

    2009-12-01

    Most coseismic, postseismic, and interseismic slip models are based on highly regularized optimizations which yield one solution which satisfies the data given a particular set of regularizing constraints. This regularization hampers our ability to answer basic questions such as whether seismic and aseismic slip overlap or instead rupture separate portions of the fault zone. We present a Bayesian methodology for generating kinematic earthquake source models with a focus on large subduction zone earthquakes. Unlike classical optimization approaches, Bayesian techniques sample the ensemble of all acceptable models presented as an a posteriori probability density function (PDF), and thus we can explore the entire solution space to determine, for example, which model parameters are well determined and which are not, or what is the likelihood that two slip distributions overlap in space. Bayesian sampling also has the advantage that all a priori knowledge of the source process can be used to mold the a posteriori ensemble of models. Although very powerful, Bayesian methods have up to now been of limited use in geophysical modeling because they are only computationally feasible for problems with a small number of free parameters due to what is called the "curse of dimensionality." However, our methodology can successfully sample solution spaces of many hundreds of parameters, which is sufficient to produce finite fault kinematic earthquake models. Our algorithm is a modification of the tempered Markov chain Monte Carlo (tempered MCMC or TMCMC) method. In our algorithm, we sample a "tempered" a posteriori PDF using many MCMC simulations running in parallel and evolutionary computation in which models which fit the data poorly are preferentially eliminated in favor of models which better predict the data. We present results for both synthetic test problems as well as for the 2007 Mw 7.8 Tocopilla, Chile earthquake, the latter of which is constrained by InSAR, local high

  1. Active Database Architectures and the Design of Sentinel for Constraint Management

    Science.gov (United States)

    1993-10-01

    Active Databases ( HiPAC ) ...................... 2 2.1.1 Comments on HiPAC ............................... 2 2.2 O de...provide a back-of-the-envelope comparison of Sentinel with other work discussed here. 2.1 High Performance Active Databases ( HiPAC ) HiPAC ([C+89b... HiPAC . Rules are treated as first class objects and each rule is an instance of the system defined rule class. Rules in HiPAC are defined by specifying a

  2. The winter day as a constraint for human activity in Western Europe

    CERN Document Server

    Martín-Olalla, José-María

    2016-01-01

    Time use surveys in Denmark, Spain, France, Ireland, Italy and United Kingdom are analyzed to provide start, noon and end times for the main activities of a society: labor (the focus of this preprint), sleeping and eating. Also, the location at home is analyzed. Local times are converted into mean solar times and compared to latitude. Observed trends allow to unveil the winter day as a restriction for the human activity. Alternatively, apparently large time differences set forth by clocks, becomes smaller when observed as a time distance to winter sunrise or sunset.

  3. Nucleosynthesis constraints on active-sterile neutrino conversions in the early universe with random magnetic field

    CERN Document Server

    Semikoz, V B

    1994-01-01

    We consider active-sterile neutrino conversions in the early universe hot plasma in the presence of a random magnetic field generated at the electroweak phase transition. Within a random field domain the magnetization asymmetry of the lepton antilepton plasma produced by a uniform constant magnetic field is huge in contrast to their small density asymmetry, leading to a drastic change in the active-sterile conversion rates. Assuming that the random field provides the seed for the galactic field one can estimate the restrictions from primordial nucleosynthesis. Requiring that the extra sterile \

  4. Ventricular activity cancellation in electrograms during atrial fibrillation with constraints on residuals' power.

    Science.gov (United States)

    Corino, Valentina D A; Rivolta, Massimo W; Sassi, Roberto; Lombardi, Federico; Mainardi, Luca T

    2013-12-01

    During atrial fibrillation (AF), cancellation of ventricular activity from atrial electrograms (AEG) is commonly performed by template matching and subtraction (TMS): a running template, built in correspondence of QRSs, is subtracted from the AEG to uncover atrial activity (AA). However, TMS can produce poor cancellation, leaving high-power residues. In this study, we propose to modulate the templates before subtraction, in order to make the residuals as similar as possible to the nearby atrial activity, avoiding high-power ones. The coefficients used to modulate the template are estimated by maximizing, via Multi-swarm Particle Swarm Optimization, a fitness function. The modulated TMS method (mTMS) was tested on synthetic and real AEGs. Cancellation performances were assessed using: normalized mean squared error (NMSE, computed on simulated data only), reduction of ventricular activity (VDR), and percentage of segments (PP) whose power was outside the standard range of the atrial power. All testings suggested that mTMS is an improvement over TMS alone, being, on simulated data, NMSE and PP significantly decreased while VDR significantly increased. Similar results were obtained on real electrograms (median values of CS1 recordings PP: 2.44 vs. 0.38 p < 0.001; VDR: 6.71 vs. 8.15 p < 0.001).

  5. Phreatic activity on Dominica (Lesser Antilles) - constraints from field investigations and experimental volcanology

    Science.gov (United States)

    Mayer, K.; Scheu, B.; Rott, S.; Dingwell, D. B.; Gilg, H. A.

    2015-12-01

    Dominica has one of the highest concentrations of potentially active volcanoes worldwide. In addition to this activity, abundant geothermal manifestations are observed at the surface, especially in the southern part of the Island. The Boiling Lake - Valley of Desolation area is one of the most vigorous ones, hosting hot springs, mud pools, fumaroles, and steam vents. Intense alteration and many, predominantly phreatic explosive features, of varying scales characterize the whole area. The most prominent manifestation of such a phreatic eruption is the Boiling Lake, a high temperature volcanic crater lake and popular tourist attraction. Thus phreatic activity is one of the main volcanic hazards on the Island, to date largely unpredictable in time and magnitude. The conditions causing these eruptions, as well as their trigger mechanisms and magnitude need to be better understood. Field mapping, together with the determination of in situ physical (density, humidity, permeability) and mechanical (strength, stiffness) properties yield the characterization of 3 main active areas with high probabilities for phreatic events. Rapid decompression experiments on samples from these areas gave insights into the fragmentation and ejection behavior. These experiments were flanked by chemical analyses and laboratory characterization (porosity, granulometry). The results show that hydrothermal alteration likely plays a crucial role in determining the probability of explosive events. High temperature acidic fluids, which lead to an intense alteration of the host rock's mineralogy, change the rock properties favoring the formation of a low permeability layer above the vent and increasing the likelihood of the site experiencing a steam-blast eruption. The contribution of these results to constraining the conditions for and the dynamics involved in phreatic eruptions provides valuable input to hazard assessment of these frequently visited sites on Dominica and similar hydrothermally

  6. Organic matter mineralization in frozen boreal soils-environmental constraints on catabolic and anabolic microbial activity

    Science.gov (United States)

    Oquist, Mats G.; Sparrman, Tobias; Schleucher, Jürgen; Nilsson, Mats B.

    2014-05-01

    Heterotrophic microbial mineralization of soil organic matter (SOM) and associated production and emission of atmospheric trace gases proceed during the winter months in the frozen soils of high latitude ecosystems. However, in what ways this microbial activity is constrained by the environmental conditions prevailing in a frozen soil matrix is uncertain. This presentation will address how temperature, water availability and substrate availability combine to regulate rates of microbial activity at below freezing temperatures and the implications of this activity for SOM mineralization in the surface layers of boreal forest soils experiencing seasonal freezing. We show that the amount and availability of liquid water is an integral factor regulating rates of microbial activity in the frozen soil matrix and can also explain frequently observed deviations in the temperature responses of biogenic CO2 production in frozen soils, as compared to unfrozen soils. Using stable isotope labeling (13C) we also show that the partitioning of substrate carbon, in the form of monomeric sugar (glucose), for catabolic and anabolic metabolism remain constant in the temperature range of -4C to 9C. This confirms that microbial growth may proceed even when soils are frozen. In addition we present corresponding data for organisms metabolizing polymeric substrates (cellulose) requiring exoenzymatic activity prior to substrate uptake. We conclude that the metabolic response of soil microorganism to controlling factors may change substantially across the freezing point of soil water, and also the patterns of interaction among controlling factors are affected. Thus, it is evident that metabolic response functions derived from investigations of unfrozen soils cannot be superimposed on frozen soils. Nonetheless, the soil microbial population appear very adapted to seasonal freezing with respect to their metabolic performance.

  7. Microbial life in frozen boreal soils-environmental constraints on catabolic and anabolic activity

    Science.gov (United States)

    Oquist, M. G.; Sparrman, T.; Haei, M.; Segura, J.; Schleucher, J.; Nilsson, M. B.

    2013-12-01

    Microbial activity in frozen soils has recently gained increasing attention and the fact that soil microorganisms can perform significant metabolic activity at temperatures below freezing is apparent. However, to what extent microbial activity is constrained by the environmental conditions prevailing in a frozen soil matrix is still very uncertain. This presentation will address how the fundamental environmental factors of temperature, liquid water availability and substrate availability combine to regulate rates of catabolic and anabolic microbial processes in frozen soils. The presented results are gained from investigations of the surface layers of boreal forest soils with seasonal freezing. We show that the amount and availability of liquid water is an integral factor regulating rates of microbial activity in the frozen soil matrix and can also explain frequently observed deviations in the temperature responses of biogenic CO2 production in frozen soils, as compared to unfrozen soils. In turn, the capacity for a specific soil to retain liquid water at sub-zero temperatures is controlled by the structural composition of the soil, and especially the soil organic matter is of integral importance. We also show that the partitioning of substrate carbon, in the form of monomeric sugar (glucose), for catabolic and anabolic metabolism remain constant in the temperature range of -4C to 9C. This confirms that microbial growth may proceed even when soils are frozen. In addition we present corresponding data for organisms metabolizing polymeric substrates (cellulose) requiring exoenzymatic activity. We conclude that the metabolic response of soil microorganism to controlling factors may change substantially across the freezing point of soil water, and also the patterns of interaction among controlling factors are affected. Thus, it is evident that metabolic response functions derived from investigations of unfrozen soils cannot be superimposed on frozen soils. Nonetheless

  8. The Modular Robots Kinematics

    Directory of Open Access Journals (Sweden)

    Claudiu Pozna

    2007-08-01

    Full Text Available The present paper intention is to develop a kinematical foundation for our nextworks in industrial robots (IR modular design. The goal of this works is todevelop cheap and improved robots which are adapted to the costumer needs. Inorder to achieve the mentioned goal, in [43], we have started a bibliographicalresearch of the main modular design aspects. The mentioned analyze of the actualresults in modular robots design gives us the possibility to establish our researchprogram. The idea of this paper is to develop a kinematical formalism which willbe use in the next dedicated to this subject.

  9. Qualitative Kinematics of Linkages

    Science.gov (United States)

    1990-05-01

    links and the connections between them, the following algorithm computes an envisionment for that system . lotatioa(P1,P2) - CCV lotatioa(P1,P2) CCV...1988 Appendix A : Slider-Crank Envisionment Each qualitative state consists of a kinematic state representing the orientation of each link, and a...8 +++ 6 -- . f. 6 000 , 7 --0 7 ++0 8 +- -+ > 1 000 1 +0+ 8 000 8 000 7 --0 7 000 8 --- m 8 +++ Appendix B : Drag-Link Envisionment Kinematic State

  10. Kinematic Optimization in Birds, Bats and Ornithopters

    Science.gov (United States)

    Reichert, Todd

    Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

  11. Active fault tolerant control of piecewise affine systems with reference tracking and input constraints

    DEFF Research Database (Denmark)

    Gholami, M.; Cocquempot, V.; Schiøler, H.

    2014-01-01

    An active fault tolerant control (AFTC) method is proposed for discrete-time piecewise affine (PWA) systems. Only actuator faults are considered. The AFTC framework contains a supervisory scheme, which selects a suitable controller in a set of controllers such that the stability and an acceptable...... the reference signal while the control inputs are bounded. The PFTC problem is transformed into a feasibility problem of a set of LMIs. The method is applied on a large-scale live-stock ventilation model.......An active fault tolerant control (AFTC) method is proposed for discrete-time piecewise affine (PWA) systems. Only actuator faults are considered. The AFTC framework contains a supervisory scheme, which selects a suitable controller in a set of controllers such that the stability and an acceptable...... performance of the faulty system are held. The design of the supervisory scheme is not considered here. The set of controllers is composed of a normal controller for the fault-free case, an active fault detection and isolation controller for isolation and identification of the faults, and a set of passive...

  12. Study of 20O via the (d,p) reaction in inverse kinematics employing the active gas target detector ANASEN

    Science.gov (United States)

    Santiago-Gonzalez, D.; Wiedenhöver, I.; Baby, L. T.; Koshchiy, E.; Rogachev, G. V.; Blackmon, J. C.; Linhardt, L. E.

    2013-10-01

    The energetic location of the d3/2-orbital in neutron-rich nuclei is of particular interest as it determines the location of the drip-line in the oxygen isotopes. Its behavior has recently been described as a consequence of three-body forces. Manifestations of such forces are traced through the location of the d3/2 orbital, which closer to stability leads to highly excited states. In order to study the location and fragmentation of this orbital in 20O a beam of the short-lived 19O was produced at the RESOLUT radioactive beam facility of the Florida State University with an intensity of 1 ×105 pps, 65 % purity and 4.11 MeV/u. The chamber of the active gas target detector ANASEN was filled with molecular deuterium gas (D2) which yielded 20O via the 19O (d , p) reaction. The ejected protons were measured with large solid angle coverage and for beam energies between 2.9 and 3.7 MeV/u. Data from the 17O(d , p) 18O reaction was acquired to verify our experimental methods and analysis techniques. We will present the latest advances in the analysis of the 19O(d , p) 20O data and demonstrate the capabilities of ANASEN. Work supported by the National Science Foundation.

  13. The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury

    Directory of Open Access Journals (Sweden)

    Domingo Antoinette

    2006-02-01

    Full Text Available Abstract Background Powered lower limb orthoses could reduce therapist labor during gait rehabilitation after neurological injury. However, it is not clear how patients respond to powered assistance during stepping. Patients might allow the orthoses to drive the movement pattern and reduce their muscle activation. The goal of this study was to test the effects of robotic assistance in subjects with incomplete spinal cord injury using pneumatically powered ankle-foot orthoses. Methods Five individuals with chronic incomplete spinal cord injury (ASIA C-D participated in the study. Each subject was fitted with bilateral ankle-foot orthoses equipped with artificial pneumatic muscles to power ankle plantar flexion. Subjects walked on a treadmill with partial bodyweight support at four speeds (0.36, 0.54, 0.72 and 0.89 m/s under three conditions: without wearing orthoses, wearing orthoses unpowered (passively, and wearing orthoses activated under pushbutton control by a physical therapist. Subjects also attempted a fourth condition wearing orthoses activated under pushbutton control by them. We measured joint angles, electromyography, and orthoses torque assistance. Results A therapist quickly learned to activate the artificial pneumatic muscles using the pushbuttons with the appropriate amplitude and timing. The powered orthoses provided ~50% of peak ankle torque. Ankle angle at stance push-off increased when subjects walked with powered orthoses versus when they walked with passive-orthoses (ANOVA, p Two of the five subjects were able to control the orthoses themselves using the pushbuttons. The other three subjects found it too difficult to coordinate pushbutton timing. Orthoses assistance and maximum ankle angle at push-off were smaller when the subject controlled the orthoses compared to when the therapist-controlled the orthoses (p Conclusion Mechanical assistance from powered ankle-foot orthoses improved ankle push-off kinematics without

  14. Calcite precipitation on glass substrates and active stalagmites in Katerloch Cave (Austria): Constraints from environmental monitoring

    Science.gov (United States)

    Sakoparnig, Marlene; Boch, Ronny; Wang, Xianfeng; Lin, Ke; Spötl, Christoph; Leis, Albrecht; Gollowitsch, Anna; Dietzel, Martin

    2016-04-01

    Located near Graz at the SE-rim of the Alps Katerloch is well-known for its impressive dripstone decoration, e.g. several metres tall and relatively fast growing (0.2-0.7 mm/yr on average) candle-stick-type stalagmites. In the course of an ongoing multi-annual and partially high-resolution cave monitoring program we study modern (active) sites of carbonate deposition focusing on the site-specific growth dynamics and connection of modern regional and cave environmental conditions with petrographic, chemical and stable isotopic information captured in the speleothems. Fresh calcite precipitates on artificial (glass) substrates underneath active drip sites were collected continuously from 2006 to 2014 (eight years!). The samples (up to 7 mm thick) represent cave sections of different temperature and drip sites of partially different characteristics (e.g. drip rate). We also recovered short drill cores (up to 3 cm length, 1 cm diameter) from the top of active stalagmites probably representing the last decades to centuries of calcite crystallization. Moreover, an actively growing stalagmite (K10) comprising both modern and past calcite deposition was collected. 238U-234U-230Th dating using MC-ICP-MS of K10 (71 cm long) revealed several distinct growth intervals (separated by growth interruptions) starting at 129.1 ±1.2 kyr BP (Last Interglacial) up to now, mostly reflecting warm and humid climate intervals. High-resolution (100 μm) isotope profiles micromilled from the multi-annual modern calcite precipitates on artificial substrates revealed low δ13C values of -12.8 to -8.3 ‰ (VPDB) and relatively high δ18O of -6.9 to -4.9 ‰Ṫhe δ18O curves from all collection sites (different growth rate) record a pronounced decrease during their most recent growth period most likely corresponding to a significant decrease towards lower oxygen isotope values observed in drip waters collected in the year 2014 compared with samples from 2005 to 2007. Drip water δ2H /δ18O

  15. Petroleum activity in the Russian Barents Sea: constraints and options for Norwegian offshore and shipping companies

    Energy Technology Data Exchange (ETDEWEB)

    Moe, Arild; Rowe, Lars

    2008-09-15

    Presently most attention in the Barents Sea is given to the Shtokman project. Experience from development of this field, where there are still many uncertainties, will have large consequences for the further development program and relations with foreign companies. The exploration activity going on is fairly limited, but over the last few years there has been a struggle over licenses and control over exploration capacity. In the medium term the goal of rapid development of the Arctic continental shelf has become intertwined with a comprehensive government effort to modernise the domestic shipbuilding industry to make it able to cover most of the needs offshore. With the shipbuilding industry in a deep crisis these goals are not fully reconcilable. Russia will either have to accept more foreign involvement, or scale down its offshore ambitions. We believe a combination of the two alternatives is likely. This means that there will still be room for foreign offshore and shipping companies, but that the total amount of activity on the continental shelf will not be as great as stated in official plans. (author). 100 refs., map

  16. Temporal and geochemical constraints on active volcanism in southeastern Papua New Guinea

    Science.gov (United States)

    Catalano, J. P.; Baldwin, S.; Fitzgerald, P. G.; Webb, L. E.; Hollocher, K.

    2010-12-01

    Active volcanism in southeastern Papua New Guinea occurs on the Papuan Peninsula (Mt. Lamington and Mt. Victory), in the Woodlark Rift (Dobu Island, SE Goodenough Island, and Western Fergusson Island), and in the Woodlark Basin. In the Woodlark Basin seafloor spreading is active and decompression melting of the mantle produces basalts. However, the cause of volcanism on the Papuan Peninsula and immediately west of active seafloor spreading rift tip in the Woodlark Basin is controversial. Previous studies have suggested active volcanism there results from 1) southward subduction of Solomon Sea lithosphere at the Trobriand Trough or 2) decompression melting as the lithosphere is extended and eventually ruptures. To evaluate these possibilities 20 samples were collected from a bimodal basalt-rhyolite suite in the D’Entrecasteaux Islands approximately 80 km west of the sea floor spreading rift tip. Siliceous ash flow tuffs on Dobu Island, Sanaroa Island, and Eastern Fergusson Island consist of sanidine/anorthoclase + Fe/Ti oxides (illmenite/ magnetite) ± quartz ± nepheline ± clinopyroxene ± xenocrystic olivine. Sanidine and K-feldspar from these ash flow tuffs yielded flat age spectra with 40Ar/39Ar isochron ages of 0.008 ± 0.002 Ma and 0.553 ± 0.001 Ma. ICP-MS trace and REE geochemistry on felsic rocks from Dobu Island and Eastern Fergusson Island yielded multi-element diagrams with enriched incompatible elements, and corresponding negative Nb, Sr, Eu, and Ti anomalies. In contrast, mafic volcanics from SE Goodenough Island are comprised of plagioclase + olivine + Fe/Ti oxides ± orthopyroxene ± clinopyroxene ± hornblende ± biotite. Biotite yielded a 40Ar/39Ar isochron age of 0.376 ± 0.05 Ma. MORB-normalized multi-element diagrams of mafic rocks from SE Goodenough Island are LREE-enriched patterns with negative Nb and positive Sr anomalies. In comparison, multi-element diagrams from previous work on mafic rocks from the New Britain arc to the north also

  17. Determining the Errors in Output Kinematic Parameters of Planar Mechanisms with a Complex Structure

    Directory of Open Access Journals (Sweden)

    Trzaska W.

    2014-11-01

    Full Text Available The study is focused on determining the errors in output kinematic parameters (position, velocity, acceleration, jerk of entire links or their selected points in complex planar mechanisms. The number of DOFs of the kinematic system is assumed to be equal to the number of drives and the rigid links are assumed to be connected by ideal, clearance-free geometric constraints. Input data include basic parameters of the mechanism with the involved errors as well as kinematic parameters of driving links and the involved errors. Output errors in kinematic parameters are determined basing on the linear theory of errors.

  18. Teaching about Kinematics

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    2009-01-01

    Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the…

  19. Real-time Design Constraints in Implementing Active Vibration Control Algorithms

    Institute of Scientific and Technical Information of China (English)

    Mohammed Alamgir Hossain; Mohammad Osman Tokhi

    2006-01-01

    Although computer architectures incorporate fast processing hardware resources, high performance real-time implementation of a complex control algorithm requires an efficient design and software coding of the algorithm so as to exploit special features of the hardware and avoid associated architecture shortcomings. This paper presents an investigation into the analysis and design mechanisms that will lead to reduction in the execution time in implementing real-time control algorithms. The proposed mechanisms are exemplified by means of one algorithm, which demonstrates their applicability to real-time applications. An active vibration control (AVC) algorithm for a flexible beam system simulated using the finite difference (FD) method is considered to demonstrate the effectiveness of the proposed methods. A comparative performance evaluation of the proposed design mechanisms is presented and discussed through a set of experiments.

  20. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    CERN Document Server

    Chen, Jiunn-Wei; Lin, Shin-Ted; Liu, C -P; Singh, Lakhwinder; Wong, Henry T; Wu, Chih-Liang; Wu, Chih-Pan

    2016-01-01

    The transition magnetic moment of a sterile-to-active neutrino conversion gives rise to not only radiative decay of a sterile neutrino, but also its non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with germanium detectors that have fine energy resolution in keV and sub-keV regimes, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from ast...

  1. Constraint-induced movement therapy after stroke.

    Science.gov (United States)

    Kwakkel, Gert; Veerbeek, Janne M; van Wegen, Erwin E H; Wolf, Steven L

    2015-02-01

    Constraint-induced movement therapy (CIMT) was developed to overcome upper limb impairments after stroke and is the most investigated intervention for the rehabilitation of patients. Original CIMT includes constraining of the non-paretic arm and task-oriented training. Modified versions also apply constraining of the non-paretic arm, but not as intensive as original CIMT. Behavioural strategies are mostly absent for both modified and original CIMT. With forced use therapy, only constraining of the non-paretic arm is applied. The original and modified types of CIMT have beneficial effects on motor function, arm-hand activities, and self-reported arm-hand functioning in daily life, immediately after treatment and at long-term follow-up, whereas there is no evidence for the efficacy of constraint alone (as used in forced use therapy). The type of CIMT, timing, or intensity of practice do not seem to affect patient outcomes. Although the underlying mechanisms that drive modified and original CIMT are still poorly understood, findings from kinematic studies suggest that improvements are mainly based on adaptations through learning to optimise the use of intact end-effectors in patients with some voluntary motor control of wrist and finger extensors after stroke.

  2. Active faulting in the Inner California Borderlands: new constraints from high-resolution multichannel seismic and multibeam bathymetric data.

    Science.gov (United States)

    Bormann, J. M.; Holmes, J. J.; Sahakian, V. J.; Klotsko, S.; Kent, G.; Driscoll, N. W.; Harding, A. J.; Wesnousky, S. G.

    2014-12-01

    Geodetic data indicate that faults offshore of Southern California accommodate 6-8 mm/yr of dextral Pacific-North American relative plate motion. In the Inner California Borderlands (ICB), modern strike-slip deformation is overprinted on topography formed during plate boundary reorganization 30-15 Ma. Despite its proximity to urban Southern California, the hazard posed by active faults in the ICB remains poorly understood. We acquired a 4000-line-km regional grid of high-resolution, 2D multichannel seismic (MCS) reflection data and multibeam bathymetry to examine the fault architecture and tectonic evolution of the ICB. We interpret the MCS data using a sequence stratigraphic approach to establish a chronostratigraphy and identify discrete episodes of deformation. We present our results in a regional fault model that distinguishes active deformation from older structures. Significant differences exist between our model of ICB deformation and existing models. Mounting evidence suggests a westward temporal migration of slip between faults in the ICB. In the eastern ICB, slip on the Newport-Inglewood/Rose Canyon fault and the neighboring Coronado Bank fault (CBF) diminishes to the north and appears to decrease over time. Undeformed Late Pliocene sediments overlie the northern extent of the CBF and the breakaway zone of the purported Oceanside Blind Thrust. Therefore, CBF slip rate estimates based on linkage with the Palos Verdes fault to the north are unwarranted. Deformation along the San Mateo, San Onofre, and Carlsbad trends is best explained as localized deformation resulting from geometrical complexities in a dextral strike-slip fault system. In the western ICB, the San Diego Trough fault (SDTF) offsets young sediments between the US/Mexico border and the eastern margin of Avalon Knoll, where the fault is spatially coincident with the San Pedro Basin fault (SPBF). Farther west, the San Clemente fault (SCF) has a strong linear bathymetric expression. The length

  3. Global Constraints on a Heavy Neutrino

    CERN Document Server

    de Gouvêa, André

    2015-01-01

    We estimate constraints on the existence of a heavy, mostly sterile neutrino with mass between 10 eV and 1 TeV. We improve upon previous analyses by performing a global combination and expanding the experimental inputs to simultaneously include tests for lepton universality, lepton flavor violating processes, electroweak precision data, dipole moments, and neutrinoless double beta decay. Assuming the heavy neutrino and its decay products are invisible to detection, we further include, in a self-consistent manner, constraints from direct kinematic searches, the kinematics of muon decay, cosmology, and neutrino oscillations, in order to estimate constraints on the values of $|U_{e4}|^2$, $|U_{\\mu4}|^2$, and $|U_{\\tau4}|^2$.

  4. Dynamic and kinematic viscosities, excess volumes and excess Gibbs energies of activation for viscous flow in the ternary mixture {1- propanol+ N,N-dimethylformamide + chloroform} at temperatures between 293.15 K and 323.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Hassein-bey-Larouci, A., E-mail: hasseinbey@yahoo.fr [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Igoujilen, O.; Aitkaci, A. [Laboratoire Thermodynamique et Modélisation Moléculaire, Faculté de Chimie, Université des Sciences et de la Technologie Houari Boumediene, B.P. 32, El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Segovia, J.J.; Villamañán, M.A. [TERMOCAL Research Group, Escuela de Ingenierías Industriales, Universidad de Valladolid, Paseo del Cauce, 59, 47011 Valladolid (Spain)

    2014-08-10

    Highlights: • Many engineering applications require quantitative thermodynamic data of the fluids. • Excess properties of mixtures are important in the understanding of mixing process. • The results are used to explain the molecular interaction in the mixtures. - Abstract: Dynamic and kinematic viscosities, and densities of the ternary mixture {x_1 propanol + x_2 DMF + x_3 chloroform} and of the three corresponding binary systems have been measured at 293.15, 303.15, 313.15 and 323.15 K and atmospheric pressure. The thermophysical properties, viscosity deviations (Δη), kinematic viscosity (γ), excess Gibbs energies of activation of viscous flow (G*{sup E}) and excess molar volumes (V{sup E}) have been calculated from experimental values of dynamic viscosity, η, and density, ρ. The different results have been correlated by the Redlich–Kister equation for the binary mixtures and the Cibulka equation for equation for the ternary ones.

  5. Kinematics of Einstein-Cartan universes

    CERN Document Server

    Pasmatsiou, Klaountia; Barrow, John D

    2016-01-01

    We analyse the kinematics of cosmological spacetimes with nonzero torsion, in the framework of the classical Einstein-Cartan gravity. After a brief introduction to the basic features of spaces with non-vanishing torsion, we consider a family of observers moving along timelike worldlines and focus on their kinematic behaviour. In so doing, we isolate the irreducible variables monitoring the observers' motion and derive their evolution formulae and associated constraint equations. Our aim is to identify the effects of spacetime torsion, and the changes they introduce into the kinematics of the standard, torsion-free, cosmological models. We employ a fully geometrical approach, imposing no restrictions on the material content, or any a priori couplings between torsion and spin. Also, we do not apply the familiar splitting of the equations, into a purely Riemannian component plus a torsion/spin part, at the start of our study, but only introduce it at the very end. With the general formulae at hand, we use the Ei...

  6. A kinematic refit for an analysis improvement at HADES

    Energy Technology Data Exchange (ETDEWEB)

    Siebenson, Johannes [TU Muenchen (Germany)

    2010-07-01

    In April 2007 pp-reactions at 3.5 GeV were measured with the HADES-Spectrometer at GSI. In these elementary reactions, one can reconstruct resonances via the missing mass technique. The kinematic refit has been employed to recalculate the momentum of measured tracks in exclusive reactions by the assumption of physical constraints. This well known procedure, can improve dramatically both the invariant- and missing- mass distributions, increasing in this way the signal to background ratio. The mathematical procedure underlying the kinematic fit will be presented, as well as experimental results achieved for the reconstruction of the {eta} and {omega} mesons and the {sigma}(1385){sup +}-resonance.

  7. A KINEMATIC STUDY OF FINSWIMMING AT SURFACE

    Directory of Open Access Journals (Sweden)

    Pier-Giorgio Zanone

    2004-06-01

    Full Text Available Finswimming is a sport of speed practiced on the surface or underwater, in which performance is based on whole-body oscillations. The present study investigated the undulatory motion performed by finswimmers at the surface. This study aiming to analyze the influence of the interaction of gender, practice level, and race distance on selected kinematic parameters. Six elite and six novices finswimmers equipped with joints markers (wrist, elbow, shoulder, hip, knee, and ankle were recorded in the sagittal plane. The position of these anatomical marks was digitized at 50 Hz. An automated motion analysis software yielded velocity, vertical amplitude, frequency, and angular position. Results showed that stroke frequency decreased whereas the mean amplitude of all joints increased with increasing race distance (p < 0.01. Mean joint amplitude for the upper limbs (wrist, elbow and shoulder was smaller for experts than for novices. Whereas that of the ankle was larger, so that the oscillation amplitude increased from shoulder to ankle. Elite male finswimmers were pitching more acutely than female. Moreover, elite male finswimmers showed a smaller knee bending than novices and than elite females (p < 0.01. This indicated that elite male finswimmers attempt to reduce drag forces thanks to a weak knee bending and a low upper limbs pitch. To sum up, gender, expertise, and race distance affect the performance and its kinematics in terms frontal drag. Expertise in finswimming requires taking advantage of the mechanical constraints pertaining to hydrodynamic constraints in order to optimize performance

  8. Kinematic Stirling Engine Performance

    Science.gov (United States)

    Tew, J. R. C.

    1986-01-01

    Computer program developed for analyzing thermodynamic characteristics of kinematic Stirling engine. Computes time-varying piston positions, pressures, and gas temperatures in each of gas-control volumes into which engine working space is divided. Engine performance characterized by calculations of power and efficiency (both indicated and brake). Inputs to code are engine geometrical parameter, engine-operating conditions, and indexes that specify various options available.

  9. Canonical quantum gravity in the Vassiliev invariants arena; 2, Constraints, habitats and consistency of the constraint algebra

    CERN Document Server

    Di Bartolo, C; Griego, J R; Pullin, J; Bartolo, Cayetano Di; Gambini, Rodolfo; Griego, Jorge; Pullin, Jorge

    2000-01-01

    In a companion paper we introduced a kinematical arena for the discussion of the constraints of canonical quantum gravity in the spin network representation based on Vassiliev invariants. In this paper we introduce the Hamiltonian constraint, extend the space of states to non-diffeomorphism invariant ``habitats'' and check that the off-shell quantum constraint commutator algebra reproduces the classical Poisson algebra of constraints of general relativity without anomalies. One can therefore consider the resulting set of constraints and space of states as a consistent theory of canonical quantum gravity.

  10. Phreatic activity in the Valley of Desolation, Dominica (Lesser Antilles) - constraints from field investigations and experimental volcanology

    Science.gov (United States)

    Mayer, Klaus; Scheu, Bettina; Montanaro, Cristian; Yilmaz, Tim; Aßbichler, Donja; Gilg, H. Albert; Dingwell, Donald B.

    2016-04-01

    Dominica has one of the highest concentrations of potentially active volcanoes worldwide, flanked by abundant surficial geothermal manifestations: The Boiling Lake - Valley of Desolation area represents one of the most vigorous ones, hosting hot springs, mud pools, fumaroles, and steam vents. Intense alteration, together with predominantly phreatic explosive features of varying scales, characterize the whole area. The last historic eruptions in Dominica occurred at the Valley of Desolation. Phreatic eruptions are also the most likely type of volcanic activity to occur in the near future at Dominica in general and the Valley of Desolation in particular. Phreatic eruptions are up to date largely unpredictable in time and magnitude, strongly asking for constraints of eruptive conditions as well as trigger mechanisms. We conducted sampling and field mapping, together with the determination of in situ physical (density, humidity, permeability) and mechanical (strength, stiffness) properties to characterize the main active surficial area which possesses a high probability for a phreatic event. Rapid decompression experiments performed on selected samples from this area give insight into the fragmentation and ejection behavior of steam driven eruptions. These experiments were flanked by chemical analyses and laboratory measurements as porosity and granulometry. The results indicate that advanced argillic alteration in the proximity of degassing vents significantly changes the rock properties, which in turn play a crucial role for the degassing of hydrothermal systems. High-temperature acidic fluids lead to an intense alteration of the host rocks, and thereby cause the formation of a kaolinite-rich, low permeable layer above the vent. In addition, alteration enhances slope instabilities causing landslides which may cover and clog the outgassing vents. Such processes increase the likelihood of the site experiencing a pressurization, which may result in a steam

  11. Development of a Kinematic 3D Carpal Model to Analyze In Vivo Soft-Tissue Interaction Across Multiple Static Postures

    OpenAIRE

    Marai, G. Elisabeta; Crisco, Joseph J; Laidlaw, David H.

    2009-01-01

    We developed a subject-specific kinematic model to analyze in vivo soft-tissue interaction in the carpus in static, unloaded postures. The bone geometry was extracted from a reference computed tomography volume image. The soft-tissue geometry, including cartilage and ligament tissues, was computationally modeled based on kinematic constraints; the constraints were extracted from multiple computed tomography scans corresponding to different carpal postures. The data collected in vivo was next ...

  12. A KBE tool for solving the mechanisms kinematics

    Science.gov (United States)

    Rusu, C.; Tiuca, T. L.; Noveanu, S.; Mândru, D.

    2016-08-01

    Knowledge-Based-Engineering (KBE) is a research field in which the methodologies and technologies for capturing and re-using the engineering knowledge are studied. Nowadays, the mechanisms design is accomplished by using various CAD software. Since, every CAD system includes KBE tools, those can be used to reduce time and simplify the mechanism's design process.One step in the design of the mechanisms with more than one degree of freedom is the direct and inverse kinematic analysis. This step can be difficult, because many calculations are involved and usually more than one solution exists. The geometrical constraints defined in the CAD system for the mechanism linkage's assembling, offer a simple solution for the kinematics analysis.This paper presents a KBE tool useful for kinematics analysis.The automation of repetitive tasks is implemented in an external application written in C# that it is also presented.

  13. Kinematics grounded on light

    CERN Document Server

    Neda, Zoltan

    2015-01-01

    The space-time of modern physics is tailored on light. We rigorously construct the basic entities needed by kinematics: geometry of the physical space and time, using as tool electromagnetic waves, and particularly light-rays. After such a mathematically orthodox construction, the special theory of relativity will result naturally. One will clearly understand and easily accept all those puzzling consequences that makes presently the special theory of relativity hard to digest. Such an approach is extremely rewarding in teaching the main ideas of Einstein's relativity theory for high-school and/or university students. Interesting speculations regarding the fundaments and future of physics are made.

  14. Kinematic geometry of gearing

    CERN Document Server

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  15. Kinematic Control of Wheeled Snake-Like Mobile Robot

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    From a bionics viewpoint , this paper proposes a mechanical model of a wheeled snake-like mobile mechanism. On the hypothesis of the existing non-holonomic constraints on the robot kinematics, we set up the relationship among the kinetic control parameters in the snake-like movement using Lie group and Lie algebra of the principle fiber bundle and provide some theoretical control methods to realize the snake-like locomotion.

  16. Kinematics of the crustal velocity field in the western US

    Science.gov (United States)

    Pollitz, F. F.

    2008-12-01

    GPS measurements embodied in PBO and PBO Nucleus allow the crustal velocity field of the western US to be constructed in unprecedented detail. Velocity and strain fields span the entire San Andreas fault system and Cascadia subduction zone from Baja California to northern Washington as well as the continental interior including the Great Basin and Wasatch Front. Rationalizing the GPS velocity field over the several tectonic regimes provides key tests of prevailing notions of interseismic crustal deformation. In our interpretation, we begin with the premise that the load-carrying portion of the lithosphere coincides with the (seismogenic) upper crust with an effective elastic thickness of ~20 km at the time scales of interseimic motions (Thatcher and Pollitz, 2008). End member kinematic models include (1) viscoelastic relaxation of the ductile lower crust and upper mantle following large earthquakes, and (2) slip in the lower elastic lithosphere, each of which serves to localize strain around major faults during interseismic periods. More detailed kinematic models emphasize the roles of lateral variations in rigidity and/or effective elastic plate thickness as well as distributed deformation. Our modeling of western US kinematics shows that the GPS velocity field is well explained with a range of models involving a combination of all of the above components; no single endmember suffices. Zones of inferred distributed deformation in the continental interior coincide with well-known seismic belts (Eastern California Shear Zone; Walker Lane; Interseismic Mountain Belt). Continued acquisition of vector constraints on crustal motions and study of available geodetic data are needed to clarify active deformation patterns in several areas. Some outstanding issues are: The nature of distributed faulting at the margins of the Great Basin (southern Nevada Transverse Zone, northern Walker Lane); understanding how dextral shear from the eastern boundary of the Sierra Nevada

  17. Effect of modified constraint-induced movement therapy on the activities of daily living of patients with acute stroke

    Directory of Open Access Journals (Sweden)

    Wei-ming ZHANG

    2015-04-01

    Full Text Available Objective To observe the rehabilitation effect of modified constraint-induced movement therapy (mCIMT on activities of daily living (ADL in patients with acute ischemic stroke.  Methods A total of 60 patients in acute stage of cerebral stroke with limb dysfunction admitted in Ruijin Hospital from December 2012 to May 2013, were randomly divided into routine rehabilitation treatment group (control group, N = 30 and mCIMT group (N = 30. Control group was given routine rehabilitation training, 60 min each time, twice per day, 5 d per week; mCIMT group received mCIMT treatment with the similar frequency. After 2-week training, all patients were transferred to rehabilitation center for 4-week continous training. The total treatment period was 6 weeks. All of those patients received assessment before treatment and 2 weeks, 6 weeks, 12 weeks after treatment on the ability of daily living and motor function, including the modified Barthel Index (mBI, Fugl-Meyer Assessment (FMA and Berg Balance Scale (BBS.  Results Patients in both groups got increased mBI (P = 0.004, 0.000, 0.000, FMA (upper limb: P = 0.000, for all and BBS scores (P = 0.005, 0.000, 0.000 2, 6, 12 weeks after treatment. FMA (lower limb score was increased 6 and 12 weeks after treatment (P = 0.000, for all. Compared to the control group, patients in mCIMT group got increased mBI (P = 0.000, for all, FMA (upper limb: P = 0.000, for all; lower limb: P = 0.000, for all and BBS scores (P = 0.000, for all 2, 6, 12 weeks after treatment.  Conclusions mCIMT has positive therapeutic effects on the motor function of limbs in hemiplegic patients with stroke in acute stage, which can improve the balance ability and the ability of daily life, so as to raise the quality of life of patients. The efficacy of mCIMT is superior to general routine rehabilitation treatment. DOI: 10.3969/j.issn.1672-6731.2015.04.006

  18. Kinematics and Workspace Analysis of a Three-Axis Parallel Manipulator: the Orthoglide

    CERN Document Server

    Pashkevich, Anatoly; Wenger, Philippe

    2006-01-01

    The paper addresses kinematic and geometrical aspects of the Orthoglide, a three-DOF parallel mechanism. This machine consists of three fixed linear joints, which are mounted orthogonally, three identical legs and a mobile platform, which moves in the Cartesian x-y-z space with fixed orientation. New solutions to solve inverse/direct kinematics are proposed and we perform a detailed workspace and singularity analysis, taking into account specific joint limit constraints.

  19. Kinematics in CTB 80

    Science.gov (United States)

    Greidanus, H.; Strom, R. G.

    1990-12-01

    This paper presents data describing the radial kinematics of the core of the complex object CTB 80, believed to be a supernova remnant. The radial velocity of the CTB 80 was found to extend between -130 and 95 km/sec (LSR), with the emission being brightest and most concentrated in filaments around -30 km/sec, and weaker at higher velocities. The character of the position-velocity diagrams was found to be consistent with models of expanding ellipsoidal shells. A comparison with these models indicated a short dimension for the core along the line of sight, and favors a momentum-driven expansion. This type of expansion is indicative of a neutron star excitation for the core of CTB 80, as opposed to a normal supernova shock.

  20. Simulating avian wingbeat kinematics.

    Science.gov (United States)

    Parslew, Ben; Crowther, William J

    2010-12-01

    Inverse dynamics methods are used to simulate avian wingbeats in varying flight conditions. A geometrically scalable multi-segment bird model is constructed, and optimisation techniques are employed to determine segment motions that generate desired aerodynamic force coefficients with minimal mechanical power output. The results show that wingbeat kinematics vary gradually with changes in cruise speed, which is consistent with experimental data. Optimised solutions for cruising flight of the pigeon suggest that upstroke wing retraction is used as a method of saving energy. Analysis of the aerodynamic force coefficient variation in high and low speed cruise leads to the proposal that a suitable gait metric should include both thrust and lift generation during each half-stroke.

  1. Rattlesnake strike behavior: kinematics

    Science.gov (United States)

    Kardong; v

    1998-03-01

    The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent.

  2. Geochemical and geochronological constraints on the origin and evolution of rocks in the active Woodlark Rift of Papua New Guinea

    Science.gov (United States)

    Zirakparvar, Nasser Alexander

    Tectonically active regions provide important natural laboratories to glean information that is applicable to developing a better understanding of the geologic record. One such area of the World is Papua New Guinea, much of which is situated in an active and transient plate boundary zone. The focus of this PhD research is to develop a better understanding of rocks in the active Woodlark Rift, situated in Papua New Guinea's southernmost reaches. In this region, rifting and lithospheric rupture is occurring within a former subduction complex where there is a history of continental subduction and (U)HP metamorphism. The lithostratigraphic units exposed in the Woodlark Rift provide an opportunity to better understand the records of plate boundary processes at many scales from micron-sized domains within individual minerals to regional geological relationships. This thesis is composed of three chapters that are independent of one another but are all related to the overall goal of developing a better understanding of the record of plate boundary processes in the rocks currently exposed in the Woodlark Rift. The first chapter, published in its entirety in Earth and Planetary Science Letters (2011 v. 309, p. 56 - 66), is entitled 'Lu-Hf garnet geochronology applied to plate boundary zones: Insights from the (U)HP terrane exhumed within the Woodlark Rift'. This chapter focuses on the use of the Lu-Hf isotopic system to date garnets in the Woodlark Rift. Major findings of this study are that some of the rocks in the Woodlark Rift preserve a Lu-Hf garnet isotopic record of initial metamorphism and continental subduction occurring in the Late Mesozoic, whereas others only preserve a record of tectonic processes related to lithospheric rupture during the initiation of rifting in the Late Cenozoic. The second chapter is entitled 'Geochemical and geochronological constraints on the origin of rocks in the active Woodlark Rift of Papua New Guinea: Recognizing the dispersed

  3. BASALT 1: Extravehicular Activity Science Operations Concepts under Communication Latency and Bandwidth Constraints at Craters of the Moon, Idaho

    Science.gov (United States)

    Chappell, Steven P.; Beaton, Kara; Miller, Matthew J.; Lim, Darlene S. S.; Abercromby, Andrew F. J.

    2017-01-01

    An over-arching goal of the multi-year Biologic Analog Science Associated with Lava Terrains (BASALT) project is to iteratively develop, implement, and evaluate concepts of operations (ConOps) and supporting capabilities intended to enable and enhance human exploration of Mars. Geological and biological scientific fieldwork is being conducted during four total deployments at two high-fidelity Mars analogs, all within simulated Mars mission conditions that are based on current architectural assumptions for Mars exploration missions. Specific capabilities being evaluated include the use of mobile science platforms, extravehicular informatics, communication and navigation packages, advanced science mission planning tools, and scientifically-relevant instrument packages to achieve the project goals. This paper describes the planning, execution, and results of the first field deployment, referred to as BASALT 1, which consisted of a series of 12 simulated extravehicular activities (EVAs) on the lava terrains of Craters of the Moon, Idaho. Scientific objectives of the EVAs related to determination of how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically-altered basalt environments. The concept of operations (ConOps) and capabilities deployed and tested during BASALT 1 were based on extensive data from previous NASA trade studies and analog testing, and the primary research question was whether those ConOps and capabilities would work acceptably when performing real (non-simulated) biological and geological scientific exploration under four different communication scenarios. Specifically, communication latencies of 5 and 15 minutes one-way light time (OWLT) were tested; these delays fall within the range of 4 to 22 minute OWLT delays that would be experienced during a Mars mission. Science operations were also conducted under low bandwidth conditions (0.512 Mb/s uplink, 1.54 Mb/s downlink), representing a

  4. Cortical fMRI activation to opponents' body kinematics in sport-related anticipation: expert-novice differences with normal and point-light video.

    Science.gov (United States)

    Wright, M J; Bishop, D T; Jackson, R C; Abernethy, B

    2011-08-18

    Badminton players of varying skill levels viewed normal and point-light video clips of opponents striking the shuttle towards the viewer; their task was to predict in which quadrant of the court the shuttle would land. In a whole-brain fMRI analysis we identified bilateral cortical networks sensitive to the anticipation task relative to control stimuli. This network is more extensive and localised than previously reported. Voxel clusters responding more strongly in experts than novices were associated with all task-sensitive areas, whereas voxels responding more strongly in novices were found outside these areas. Task-sensitive areas for normal and point-light video were very similar, whereas early visual areas responded differentially, indicating the primacy of kinematic information for sport-related anticipation.

  5. Microgravity Vibration Isolation System Based on Parallel Kinematic Communications

    Science.gov (United States)

    Russkin, Alexander; Postojuk, Nikolay

    The paper is devoted to the construction of an active vibration isolation system of experimental and technological equipment operating in microgravity conditions. Space experiments associated with obtaining ultrapure materials are required the residual level of microgravity vibration from mmug to mg at the frequency range from 0.01 Hz to 100 Hz in the experiment area. This residual level of microgravity vibration is difficult to achieve by conventional passive protection systems. To date the different types of active vibration isolation systems are constructed, such as STABLE, ARIS, MIM, g-LIMIT and MVIS, but their characteristics and geometrical parameters do not always satisfy the given technological requirements. In this paper, the mechanism with parallel kinematic constraints (MPKS) is proposed for constructing microgravity active vibration isolation system, which provides protection against vibrations in six degrees of freedom and can be scaled depending on the specific tasks. MPKS distinguishing feature is the presence of closed kinematic chain, which provide high rigidity of the structure, reduce the mass of moving parts and reduce the load on the actuator. As a result, this increases the dynamics and positioning accuracy MPKS. The proposed version of microgravity vibration isolation system consists of two main parts: the electromechanical assembly and control unit. The main specifications for the constituent parts of the system are defined. A comparative analysis of different types of actuators and sensors for electromechanical assembly is carried out. The appropriate components to provide the desired specifications are selected. There are proposed to use piezoelectric motors as actuators in electromechanical assembly. Mathematical models of MPKS with six degrees of freedom and control system are considered. The structure of the control system and controller type is selected. A mathematical model of proposed microgravity vibration isolation system is

  6. Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing

    Directory of Open Access Journals (Sweden)

    Bettina eMohr

    2014-11-01

    Full Text Available The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a two-week treatment interval with intensive constraint induced aphasia therapy (CIAT, which is also called intensive language action therapy (ILAT. Functional magnetic resonance imaging (fMRI was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signals was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologues of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

  7. Changes of right-hemispheric activation after constraint-induced, intensive language action therapy in chronic aphasia: fMRI evidence from auditory semantic processing.

    Science.gov (United States)

    Mohr, Bettina; Difrancesco, Stephanie; Harrington, Karen; Evans, Samuel; Pulvermüller, Friedemann

    2014-01-01

    The role of the two hemispheres in the neurorehabilitation of language is still under dispute. This study explored the changes in language-evoked brain activation over a 2-week treatment interval with intensive constraint induced aphasia therapy (CIAT), which is also called intensive language action therapy (ILAT). Functional magnetic resonance imaging (fMRI) was used to assess brain activation in perilesional left hemispheric and in homotopic right hemispheric areas during passive listening to high and low-ambiguity sentences and non-speech control stimuli in chronic non-fluent aphasia patients. All patients demonstrated significant clinical improvements of language functions after therapy. In an event-related fMRI experiment, a significant increase of BOLD signal was manifest in right inferior frontal and temporal areas. This activation increase was stronger for highly ambiguous sentences than for unambiguous ones. These results suggest that the known language improvements brought about by intensive constraint-induced language action therapy at least in part relies on circuits within the right-hemispheric homologs of left-perisylvian language areas, which are most strongly activated in the processing of semantically complex language.

  8. Fault-related fold kinematics recorded by terrestrial growth strata, Sant Llorenç de Morunys, Pyrenees Mountains, NE Spain

    Science.gov (United States)

    Carrigan, James H.; Anastasio, David J.; Kodama, Kenneth P.; Parés, Josep M.

    2016-10-01

    Foreland basin growth strata are ideal recorders of deformation rates and kinematics in tectonically active regions. This study develops a high-resolution chronostratigraphic age model to determine folding rates in the Eocene-Oligocene terrestrial growth strata of the Berga Conglomerate Group, NE Spain. The Berga Conglomerate Group was sampled for rock magnetic, magnetostratigraphic, and magnetic susceptibility (χ) cyclostratigraphy analyses. Analysis of rock magnetic measurements indicate a mixed mineral assemblage with both paramagnetic and ferromagnetic minerals. A new magnetic reversal stratigraphy constrains the time frame of folding and is in agreement with previous interpretations. Time series analysis of χ variations show statistically significant power at expected orbital frequencies and provides precession-scale (20 kyr) temporal resolution. Strain measurements including anisotropy of magnetic susceptibility (AMS) fabrics and bedding plane strain worm burrow distortion are consistent with fixed hinge, flexural folding kinematics. Fault-related folding was modeled using χ cyclostratigraphy timing and strain measurement kinematic constraints. The onset of folding was at 33.85 Ma and the end of deformation is less constrained but is younger than 31.06 Ma. Deformation and sediment accumulation rates are unsteady at 20 kyr time scales but appear artificially steady at polarity chron time scales.

  9. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan

    2011-01-01

    The relationship between creativity and constraints is often described in the literature either in rather imprecise, general concepts or in relation to very specific domains. Cross-domain and cross-disciplinary takes on how the handling of constraints influences creative activities are rare. In t......-disciplinary research into the ambiguous role of constraints in creativity....

  10. On the kinematic age of RZ Psc

    Science.gov (United States)

    Potravnov, I. S.; Grinin, V. P.

    2013-11-01

    RZ Psc belongs to the family of young UX Ori stars whose photometric activity is due to strong extinction variations in the circumstellar disks surrounding them. However, in contrast to all the remaining stars of this type, no evidence of youth has been detected for RZ Psc until recently. A rough estimate of the star's kinematic age was made for the first time in our previous paper (Grinin et al. 2010). It shows that RZ Psc is intermediate in its evolutionary status between young stars in Orion and stars with debris disks. In this paper, we provide a refined estimate of the kinematic age for the star confirming this conclusion. According to this estimate, the age of RZ Psc is approximately 25 ± 5 Myr at M * = 1 M ⊙.

  11. SKIRT: Stellar Kinematics Including Radiative Transfer

    Science.gov (United States)

    Baes, Maarten; Dejonghe, Herwig; Davies, Jonathan

    2011-09-01

    SKIRT is a radiative transfer code based on the Monte Carlo technique. The name SKIRT, acronym for Stellar Kinematics Including Radiative Transfer, reflects the original motivation for its creation: it has been developed to study the effects of dust absorption and scattering on the observed kinematics of dusty galaxies. In a second stage, the SKIRT code was extended with a module to self-consistently calculate the dust emission spectrum under the assumption of local thermal equilibrium. This LTE version of SKIRT has been used to model the dust extinction and emission of various types of galaxies, as well as circumstellar discs and clumpy tori around active galactic nuclei. A new, extended version of SKIRT code can perform efficient 3D radiative transfer calculations including a self-consistent calculation of the dust temperature distribution and the associated FIR/submm emission with a full incorporation of the emission of transiently heated grains and PAH molecules.

  12. Kinematics of Haro11 - the miniature Antennae

    CERN Document Server

    Östlin, Göran; Cumming, Robert; Fathi, Kambiz; Bergvall, Nils; Adamo, Angela; Amram, Philippe; Hayes, Matthew

    2015-01-01

    (abridged) Luminous blue compact galaxies are among the most active galaxies in the local universe in terms of their star formation rate per unit mass. They may be seen as the local analogs of higher redshift Lyman Break Galaxies. Studies of their kinematics is key to understanding what triggers their unusually active star formation In this work we investigate the kinematics of stars and ionised gas in Haro11, one of the most luminous blue compact galaxies in the local universe. Previous works have indicated that many such galaxies may be triggered by galaxy mergers. We have employed Fabry-Perot interferometry, long-slit spectroscopy and Integral Field Unit (IFU) spectroscopy to explore the kinematics of Haro11. We target the near infrared Calcium triplet to derive the stellar velocity field and velocity dispersion. Ionised gas is analysed through emission lines from hydrogen, [OIII] , and [SIII]. When spectral resolution and signal to noise allows we investigate the the line profile in detail and identify mu...

  13. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  14. Kinematic precision of gear trains

    Science.gov (United States)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  15. LIVE KINEMATIC MODELS IN MATHCAD

    Directory of Open Access Journals (Sweden)

    Valery F. Ochkov

    2013-01-01

    Full Text Available The paper considers creating animation of different kinematical devices in mathematical package Mathcad (steam engine, windscreen wipers, walking machine. Mathematical tools for solving algebraic equations and their systems are described. 

  16. Tensor Networks from Kinematic Space

    CERN Document Server

    Czech, Bartlomiej; McCandlish, Samuel; Sully, James

    2015-01-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space---the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  17. Tensor networks from kinematic space

    Science.gov (United States)

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Sully, James

    2016-07-01

    We point out that the MERA network for the ground state of a 1+1-dimensional conformal field theory has the same structural features as kinematic space — the geometry of CFT intervals. In holographic theories kinematic space becomes identified with the space of bulk geodesics studied in integral geometry. We argue that in these settings MERA is best viewed as a discretization of the space of bulk geodesics rather than of the bulk geometry itself. As a test of this kinematic proposal, we compare the MERA representation of the thermofield-double state with the space of geodesics in the two-sided BTZ geometry, obtaining a detailed agreement which includes the entwinement sector. We discuss how the kinematic proposal can be extended to excited states by generalizing MERA to a broader class of compression networks.

  18. Spatially Resolving the Kinematics of the <100 {\\mu}as Quasar Broad Line Region using Spectroastrometry

    CERN Document Server

    Stern, Jonathan; Pott, Jörg-Uwe

    2015-01-01

    The broad line region (BLR) of luminous active galactic nuclei (AGN) is a prominent observational signature of the accretion flow around supermassive black holes, which can be used to measure their masses (M_BH) over cosmic history. Due to the <100 {\\mu}as angular size of the BLR, current direct constraints on BLR kinematics are limited to those provided by reverberation mapping studies, which are most efficiently carried out on low-luminosity L and low-redshift z AGN. We analyze the possibility to measure the BLR size and study its kinematic structure using spectroastrometry, whereby one measures the spatial position centroid of emission line photons as a function of velocity. We calculate the expected spectroastrometric signal of a rotation-dominated BLR for various assumptions about the ratio of random to rotational motions, and the radial distribution of the BLR gas. We show that for hyper-luminous quasars at z < 2.5, the size of the low-ionization BLR can already be constrained with existing telesc...

  19. Automatic Design Theory and Realization of Kinematic Schemes for Mechanism System

    Institute of Scientific and Technical Information of China (English)

    YE Zhi-gang; ZOU Hui-jun; GUO Wei-zhong; HU Song; TIAN Yong-li; XU Yong

    2006-01-01

    Based on an analysis of mechanism combination methods of a current mechanism system kinematic scheme,inpuf/output kinematic behavior and their constraint relations were proposed to represent the kinematic behavior knowledge of a mechanism system.Furthermore,a tree stmcture of a kinematic behavior decomposition process for a mechanism system was provided.Considering multiple outputs for a mechanism system,the matching algorithm and the attributes propagation method of kinematic behavior were used to generate a mechanism combination scheme.Its intermediate design solution and the constraint relations between input and output are generated to fill the common blackboard.Moreover,using information in the blackboard as input motion.the behavior attributes of other process actions are transmitted to attribute items of the blackboard,which finally enables a computer-aided automatic design process of a mechanism system kinematic scheme.To avoid the problem of schemes combination explosion caused by unbounded depth in the search process,bounded depth-first search was used to control the number of expanded hierarchies for a design tree.Finally.an example was given to show its feasibility and solution efficiency.

  20. Kinematics, seismotectonics and seismic potential of the eastern sector of the European Alps from GPS and seismic deformation data

    Science.gov (United States)

    Serpelloni, E.; Vannucci, G.; Anderlini, L.; Bennett, R. A.

    2016-10-01

    We present a first synoptic view of the seismotectonics and kinematics of the eastern sector of the European Alps using geodetic and seismological data. The study area marks the boundary between the Adriatic and the Eurasian plates, through a wide zone of deformation including a variety of tectonic styles within a complex network of crustal and lithospheric faults. A new dense GPS velocity field, new focal mechanisms and seismic catalogues, with uniformly re-calibrated magnitudes (from 1005), are used to estimate geodetic and seismic deformation rates and to develop interseismic kinematic and fault locking models. Kinematic indicators from seismological and geodetic data are remarkably consistent at different spatial scales. In addition to large-scale surface motion, GPS velocities highlight more localized deformation features revealing a complex configuration of interacting tectonic blocks, for which new constraints are provided in this work accounting for elastic strain build up at faults bonding rotating blocks. The geodetic and seismological data highlight two belts of higher deformation rates running WSW-ENE along the Eastern Southern Alps (ESA) in Italy and E-W in Slovenia, where deformation is more distributed. The highest geodetic strain-rates are observed in the Montello-Cansiglio segment of the ESA thrust front, for which the higher density of the GPS network provides indications of limited interseismic locking. Most of the dextral shear between the Eastern Southern Alps and the Eastern Alps blocks is accommodated along the Fella-Sava fault rather than the Periadriatic fault. In northern Croatia and Slovenia geodetic and seismological data allow constraining the kinematics of the active structures bounding the triangular-shaped region encompassing the Sava folds, which plays a major role in accommodating the transition from Adria- to Pannonian-like motion trends. The analysis of the seismic and geodetic moment rates provides new insights into the seismic

  1. Mg II & C IV Kinematics vs. Stellar Kinematics in Galaxies

    CERN Document Server

    Churchill, C W; Churchill, Chris; Steidel, Chuck

    2002-01-01

    Comparisons of the kinematics of Mg II absorbing gas and the stellar rotation curves in 0.5 < z < 1.0 spiral galaxies suggests that, at least in some cases, the extended gaseous envelopes may be dynamically coupled to the stellar matter. A strong correlation exists between the overall kinematic spread of Mg II absorbing gas and C IV absorption strength, and therefore kinematics of the higher-ionization gas. Taken together, the data may suggest a "halo/disk connection" between z~1 galaxies and their extended gaseous envelopes. Though the number of galaxies in our sample are few, there are no clear examples that suggest the gas is accreting/infalling isotropically about the galaxies from the intergalactic medium.

  2. Radiative distortion of kinematic edges in cascade decays

    CERN Document Server

    Beneke, Martin; Mück, Alexander; Ubiali, Maria

    2016-01-01

    Kinematic edges of cascade decays of new particles produced in high-energy collisions may provide important constraints on the involved particles' masses. For the exemplary case of gluino decay $\\tilde{g}\\to q\\bar q \\tilde{\\chi}$ into a pair of quarks and a neutralino through a squark resonance, we study the hadronic invariant mass distribution in the vicinity of the kinematic edge. We perform a next-to-leading order calculation in the strong coupling $\\alpha_s$ and the ratio of squark width and squark mass $\\Gamma_\\tilde{q}/m_\\tilde{q}$, based on a systematic expansion in $\\Gamma_\\tilde{q}/m_\\tilde{q}$. The separation into hard, collinear and soft contributions elucidates the process dependent and universal features of distributions in the edge region, represented by on-shell decay matrix elements, universal jet functions and a soft function that depends on the resonance propagator and soft Wilson lines.

  3. Kinematics and computation of workspace for adaptive geometry structures

    Science.gov (United States)

    Pourki, Forouza; Sosa, Horacio

    1993-09-01

    A new feature in the design of smart structures is the capability of the structure to respond autonomously to undesirable phenomena and environment. This capability is often synonymous to the requirement that the structure should assume a set of different geometric shapes or adapt to a set of kinematic constraints to accomplish a maneuver. Systems with these characteristics have been referred to as `shape adaptive' or `variable geometry' structures. The present paper introduces a basis for the kinematics and work space studies of statically deterministic truss structures which are shape adaptive. The difference between these structures and the traditional truss structures, which are merely built to support the weight and may be modelled by finite element methods, is the fact that these variable geometry structures allow for large (and nonlinear) deformations. On the other hand, these structures unlike structures composed of well investigated `four bar mechanisms,' are statically deterministic.

  4. A constrained generalised- method for coupling rigid parallel chain kinematics and elastic bodies

    Science.gov (United States)

    Gransden, Derek I.; Bornemann, P. Burkhard; Rose, Michael; Nitzsche, Fred

    2015-03-01

    A problem arises from combining flexible rotorcraft blades with stiffer mechanical links, which form a parallel kinematic chain. This paper introduces a method for solving index-3 differential algebraic equations for coupled stiff and elastic body systems with closed-loop kinematics. Rigid body dynamics and elastic body mechanics are independently described according to convenient mathematical measures. Holonomic constraint equations couple both the parallel chain kinematics and describe the coupling between the rigid and continuum bodies. Lagrange multipliers enforce the kinetic conditions for both sets of constraints. Additionally, to prevent numerical inaccuracy from inverting stiff mechanical matrices, a scaling factor normalises the dynamic tangential stiffness matrix. Finally, example tests show the verification of the algorithm with respect to existing computational tests and the accuracy of the model for cases relevant to the problem definition.

  5. KINEMATIC DESIGN OF A RECONFIGURABLE MINIATURE PARALLEL KINEMATIC MACHINE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The kinematic design of a reconfigurable miniature parallel kinematic machine is dealt with. It shows that the reconfigurability may be realized by packaging a tripod-based parallel mechanism with fixed length struts into a compact and rigid frame with which the different configurations can be formed. Utilizing a dual parameter model, the influences of the geometrical parameters on the dexterous performance and the workspace/machine volume ratio are investigated. A novel global performance index for the dimensional synthesis is proposed and optimized, resulting in a set of dimensionless geometrical parameters.

  6. Tibiofemoral conformity and kinematics of rotating-bearing knee prostheses.

    Science.gov (United States)

    D'Lima, D D; Trice, M; Urquhart, A G; Colwell, C W

    2001-05-01

    Increasing tibiofemoral articular conformity theoretically increases articular contact area and reduces contact stresses in total knee arthroplasty. Fixed-bearing knee designs possess relatively low tibiofemoral conformity, in part to allow tibiofemoral rotation without generating excessive stresses at the articulation or the implant-bone interface. This study analyzed knee kinematics of mobile-bearing designs in a closed chain dynamic knee extension model in posterior cruciate-retaining design with high- and low tibiofemoral conformity and posterior cruciate-substituting designs with and without rotational constraint. Overall, for all conditions, the mobile-bearing insert rotated with the femur in the presence of tibiofemoral axial rotation. In addition, the correlation of bearing rotation with femoral rotation was stronger for the high-conformity and rotationally-constrained designs than for the low-conformity designs and strongest for the posterior cruciate-retaining high-conformity condition. Changes in conformity or rotational constraint did not appear to affect femoral roll back, tibiofemoral axial rotation, or varus-valgus angulation. The results suggest that mobile-bearing inserts rotate with the femur and increasing conformity or rotational constraint in mobile-bearing design knee prostheses does not affect knee kinematics adversely, at least under closed chain knee extension conditions in vitro.

  7. Stochastic Constraint Programming

    OpenAIRE

    Walsh, Toby

    2009-01-01

    To model combinatorial decision problems involving uncertainty and probability, we introduce stochastic constraint programming. Stochastic constraint programs contain both decision variables (which we can set) and stochastic variables (which follow a probability distribution). They combine together the best features of traditional constraint satisfaction, stochastic integer programming, and stochastic satisfiability. We give a semantics for stochastic constraint programs, and propose a number...

  8. Clifford Fibrations and Possible Kinematics

    Directory of Open Access Journals (Sweden)

    Alan S. McRae

    2009-07-01

    Full Text Available Following Herranz and Santander [Herranz F.J., Santander M., Mem. Real Acad. Cienc. Exact. Fis. Natur. Madrid 32 (1998, 59-84, physics/9702030] we will construct homogeneous spaces based on possible kinematical algebras and groups [Bacry H., Levy-Leblond J.-M., J. Math. Phys. 9 (1967, 1605-1614] and their contractions for 2-dimensional spacetimes. Our construction is different in that it is based on a generalized Clifford fibration: Following Penrose [Penrose R., Alfred A. Knopf, Inc., New York, 2005] we will call our fibration a Clifford fibration and not a Hopf fibration, as our fibration is a geometrical construction. The simple algebraic properties of the fibration describe the geometrical properties of the kinematical algebras and groups as well as the spacetimes that are derived from them. We develop an algebraic framework that handles all possible kinematic algebras save one, the static algebra.

  9. Clifford Fibrations and Possible Kinematics

    Science.gov (United States)

    McRae, Alan S.

    2009-07-01

    Following Herranz and Santander [Herranz F.J., Santander M., Mem. Real Acad. Cienc. Exact. Fis. Natur. Madrid 32 (1998), 59-84, physics/9702030] we will construct homogeneous spaces based on possible kinematical algebras and groups [Bacry H., Levy-Leblond J.-M., J. Math. Phys. 9 (1967), 1605-1614] and their contractions for 2-dimensional spacetimes. Our construction is different in that it is based on a generalized Clifford fibration: Following Penrose [Penrose R., Alfred A. Knopf, Inc., New York, 2005] we will call our fibration a Clifford fibration and not a Hopf fibration, as our fibration is a geometrical construction. The simple algebraic properties of the fibration describe the geometrical properties of the kinematical algebras and groups as well as the spacetimes that are derived from them. We develop an algebraic framework that handles all possible kinematic algebras save one, the static algebra.

  10. Constraints from Cosmography in Various Parametrizations

    Science.gov (United States)

    Aviles, Alejandro; Gruber, Christine; Luongo, Orlando; Quevedo, Hernando

    2015-01-01

    We use cosmography to present constraints on the kinematics of the Universe without postulating any underlying theoretical model a priori. To this end, we use a Markov Chain Monte Carlo analysis to perform comparisons to the supernova Ia union 2 compilation, combined with the Hubble Space Telescope measurements of the Hubble constant, and the Hubble parameter datasets. The cosmographic approach to our analysis is revisited and extended for new notions of redshift presented as alternatives to the redshift z. Furthermore, we introduce a new set of fitting parameters describing the kinematical evolution of the Universe in terms of the equation of state of the Universe and derivatives of the total pressure. Our results are consistent with the ΛCDM model, although alternative models, with nearly constant pressure and no cosmological constant, match the results accurately as well.

  11. Data reporting constraints for the lymphatic filariasis mass drug administration activities in two districts in Ghana: A qualitative study.

    Science.gov (United States)

    da-Costa Vroom, Frances Baaba; Aryeetey, Richmond; Boateng, Richard; Anto, Francis; Aikins, Moses; Gyapong, Margaret; Gyapong, John

    2015-01-01

    Timely and accurate health data are important for objective decision making and policy formulation. However, little evidence exists to explain why poor quality routine health data persist. This study examined the constraints to data reporting for the lymphatic filariasis mass drug administration programme in two districts in Ghana. This qualitative study focused on timeliness and accuracy of mass drug administration reports submitted by community health volunteers. The study is nested within a larger study focusing on the feasibility of mobile phone technology for the lymphatic filariasis programme. Using an exploratory study design, data were obtained through in-depth interviews (n = 7) with programme supervisors and focus group discussions (n = 4) with community health volunteers. Results were analysed using thematic content analysis. Reasons for delays in reporting were attributed to poor numeracy skills among community health volunteers, difficult physical access to communities, high supervisor workload, poor adherence reporting deadlines, difficulty in reaching communities within allocated time and untimely release of programme funds. Poor accuracy of data was mainly attributed to inadequate motivation for community health volunteers and difficulty calculating summaries. This study has shown that there are relevant issues that need to be addressed in order to improve the quality of lymphatic filariasis treatment coverage reports. Some of the factors identified are problems within the health system; others are specific to the community health volunteers and the lymphatic filariasis programme. Steps such as training on data reporting should be intensified for community health volunteers, allowances for community health volunteers should be re-evaluated and other non-monetary incentives should be provided for community health volunteers.

  12. Development of a Kinematic 3D Carpal Model to Analyze In Vivo Soft-Tissue Interaction Across Multiple Static Postures

    Science.gov (United States)

    Marai, G. Elisabeta; Crisco, Joseph J.; Laidlaw, David H.

    2012-01-01

    We developed a subject-specific kinematic model to analyze in vivo soft-tissue interaction in the carpus in static, unloaded postures. The bone geometry was extracted from a reference computed tomography volume image. The soft-tissue geometry, including cartilage and ligament tissues, was computationally modeled based on kinematic constraints; the constraints were extracted from multiple computed tomography scans corresponding to different carpal postures. The data collected in vivo was next coupled with numerical simulation in order to analyze the role of soft-tissues in different postures. The resulting model extends the state of biomecanical modeling by incorporating soft-tissue constraints across the carpus range of motion, while successfully using only physiological constraints. The model results suggest that soft-tissue wrapping constraints have substantial impact on carpus stability. PMID:19965271

  13. Latest Advances in Robot Kinematics

    CERN Document Server

    Husty, Manfred

    2012-01-01

    This book is  of interest to researchers inquiring about modern topics and methods in the kinematics, control and design of robotic manipulators. It considers the full range of robotic systems, including serial, parallel and cable driven manipulators, both planar and spatial. The systems range from being less than fully mobile to kinematically redundant to overconstrained. In addition to recognized areas, this book also presents recent advances in emerging areas such as the design and control of humanoids and humanoid subsystems, and the analysis, modeling and simulation of human body motions, as well as the mobility analysis of protein molecules and the development of machines which incorporate man.

  14. Kinematics of the Danakil microplate

    Science.gov (United States)

    Eagles, Graeme; Gloaguen, Richard; Ebinger, Cynthia

    2002-10-01

    A refinement and extrapolation of recent motion estimates for the Danakil microplate, based on ancient kinematic indicators in the Afar region, describes the evolution of a microplate in the continental realm. The Danakil horst is an elevated part of this microplate, exposing a Precambrian basement within the Afar depression, the site of the Nubia-Somalia-Arabia triple junction. We compare evidence for strike- or oblique-slip faults in data from the Afar depression and southern Red Sea to small circles about published poles of rotation for the Danakil microplate with respect to Nubia. A reconstruction about the preferred pole reunites lengths of a Precambrian shear zone on the Nubia and Danakil sides and preserves a uniform basement fabric strike through Nubia, Danakil and Yemen. Since at least magnetic chron C5 (˜11 Ma) Danakil rotated about a different pole with respect to Nubia than either Somalia or Arabia, but between chrons C5 and C2A Nubia-Danakil motion was a close approximation to Nubia-Somalia motion. Since C2A relative motions of the Danakil microplate have been independent of movements on any of the neighbouring plate boundaries. We relate this to the onset of oceanic-type accretion within Afar. The resulting eastwards acceleration of Danakil was accommodated by westwards propagation of the Gulf of Aden rift that became the new, discrete, plate boundary between the Danakil microplate and the Somalia plate. Present-day activity suggests that the Red Sea and Aden rifts will link through Afar, thereby isolating the Danakil horst as a microcontinent on the Arabian margin.

  15. Ordered Kinematic Endpoints for 5-body Cascade Decays

    CERN Document Server

    Klimek, Matthew D

    2016-01-01

    We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.

  16. Stability analysis for natural slope by kinematical approach

    Institute of Scientific and Technical Information of China (English)

    孙志彬; 覃长兵

    2014-01-01

    The stability of natural slope was analyzed on the basis of limit analysis. The sliding model of a kind of natural slope was presented. A new kinematically admissible velocity field for the new sliding model was constructed. The stability factor formulation by the upper bound theorem leads to a classical nonlinear programming problem, when the external work rate and internal energy dissipation were solved, and the constraint condition of the programming problem was given. The upper bound optimization problem can be solved efficiently by applying a nonlinear SQP algorithm, and stability factor was obtained, which agrees well with previous achievements.

  17. Deep Explosive Volcanism on the Gakkel Ridge and Seismological Constraints on Shallow Recharge at TAG Active Mound

    Science.gov (United States)

    2013-02-01

    in the mantle, where rigid tectonic plates move apart and new seafloor material rises to fill the vacant space. The generation of new plate material...focus on shallow seismic activity beneath the hydrothermal mound. The OBS network also detected a large number of local and regional tectonic events...hydrothermal mound with the larger-scale seismicity associated with tectonic extension on the active detachment fault [deMartin et al., 2007]. Thermal

  18. Impact responses of the cervical spine: A computational study of the effects of muscle activity, torso constraint, and pre-flexion.

    Science.gov (United States)

    Nightingale, Roger W; Sganga, Jake; Cutcliffe, Hattie; Bass, Cameron R 'Dale'

    2016-02-29

    Cervical spine injuries continue to be a costly societal problem. Future advancements in injury prevention depend on improved physical and computational models, which are predicated on a better understanding of the neck response during dynamic loading. Previous studies have shown that the tolerance of the neck is dependent on its initial position and its buckling behavior. This study uses a computational model to examine three important factors hypothesized to influence the loads experienced by vertebrae in the neck under compressive impact: muscle activation, torso constraints, and pre-flexion angle of the cervical spine. Since cadaver testing is not practical for large scale parametric analyses, these factors were studied using a previously validated computational model. On average, simulations with active muscles had 32% larger compressive forces and 25% larger shear forces-well in excess of what was expected from the muscle forces alone. In the short period of time required for neck injury, constraints on torso motion increased the average neck compression by less than 250N. The pre-flexion hypothesis was tested by examining pre-flexion angles from neutral (0°) to 64°. Increases in pre-flexion resulted in the largest increases in peak loads and the expression of higher-order buckling modes. Peak force and buckling modality were both very sensitive to pre-flexion angle. These results validate the relevance of prior cadaver models for neck injury and help explain the wide variety of cervical spine fractures that can result from ostensibly similar compressive loadings. They also give insight into the mechanistic differences between burst fractures and lower cervical spine dislocations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Top quark mass and kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Barberis, Emanuela; /Northeastern U.

    2006-05-01

    A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.

  20. Effects of hip joint centre mislocation on gait kinematics of children with cerebral palsy calculated using patient-specific direct and inverse kinematic models.

    Science.gov (United States)

    Kainz, Hans; Carty, Christopher P; Maine, Sheanna; Walsh, Henry P J; Lloyd, David G; Modenese, Luca

    2017-09-01

    Joint kinematics can be calculated by Direct Kinematics (DK), which is used in most clinical gait laboratories, or Inverse Kinematics (IK), which is mainly used for musculoskeletal research. In both approaches, joint centre locations are required to compute joint angles. The hip joint centre (HJC) in DK models can be estimated using predictive or functional methods, while in IK models can be obtained by scaling generic models. The aim of the current study was to systematically investigate the impact of HJC location errors on lower limb joint kinematics of a clinical population using DK and IK approaches. Subject-specific kinematic models of eight children with cerebral palsy were built from magnetic resonance images and used as reference models. HJC was then perturbed in 6mm steps within a 60mm cubic grid, and kinematic waveforms were calculated for the reference and perturbed models. HJC perturbations affected only hip and knee joint kinematics in a DK framework, but all joint angles were affected when using IK. In the DK model, joint constraints increased the sensitivity of joint range-of-motion to HJC location errors. Mean joint angle offsets larger than 5° were observed for both approaches (DK and IK), which were larger than previously reported for healthy adults. In the absence of medical images to identify the HJC, predictive or functional methods with small errors in anterior-posterior and medial-lateral directions and scaling procedures minimizing HJC location errors in the anterior-posterior direction should be chosen to minimize the impact on joint kinematics. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Dynamics and causality constraints in field theory

    CERN Document Server

    De Souza, M M

    1997-01-01

    We discuss the physical meaning and the geometric interpretation of causality implementation in classical field theories. Causality is normally implemented through kinematical constraints on fields but we show that in a zero-distance limit they also carry a dynamical information, which calls for a revision of our standard concepts of interacting fields. The origin of infinities and other inconsistencies in field theories is traced to fields defined with support on the lightcone; a finite and consistent field theory requires a lightcone generator as the field support.

  2. Examination of center of pressure displacement and muscle activity of the hip girdle muscles on lateral movement in the sitting position, focusing on kinematic features before and after the start of exercise

    Science.gov (United States)

    Ikeda, Kouji; Suehiro, Kenji; Kizu, Akito; Kunieda, Hideki; Takasaki, Hirokazu; Suzuki, Toshiaki

    2017-01-01

    [Purpose] This study aimed to evaluate the kinematic characteristics at the start of lateral movement in the sitting position, for application in physical therapy. [Subjects and Methods] Eleven healthy male subjects (mean age, 24.8 ± 3.7 years) were included in the study after they provided informed consent. The electromyographic activities of the tensor fascia lata, gluteus medius, and rectus femoris, and the center of pressure (COP) displacement during lateral reach in the sitting position were measured. The task was recorded on video for analysis. [Results] In almost all subjects, before the beginning of the task, the electromyographic activity in the opposite side of each studied muscle was recorded, and the opposite and anterior displacement of the COP was observed. The video analysis revealed that all subjects showed lateral displacement of the thoracic part of the trunk after the start of the task. However, the lumbar region and pelvis maintained their starting positions. [Conclusion] COP displacement occurred in the reverse reaction before the task, and this involved the hip girdle muscles of the opposite side. A reverse reaction displaced the pelvis to the opposite side to ensure instability of posture through side tilting of the trunk at the beginning of the task. PMID:28356627

  3. Modulation of constitutive activity and signaling bias of the ghrelin receptor by conformational constraint in the second extracellular loop

    DEFF Research Database (Denmark)

    Mokrosinski, Jacek; Frimurer, Thomas M; Sivertsen, Bjoern

    2012-01-01

    phenotypes as the negatively charged Glu residue. Computational chemistry analysis indicated that the propensity for the C-terminal segment of ECL2b to form an extended a-helix was increased from 15% in the wild type to 89% and 82% by introduction in position 204(C+6) of a Glu or a Lys residue, respectively....... Moreover, the constitutive activity of the receptor was inhibited by Zn(2+) binding in an engineered metal-ion site stabilizing an a-helical conformation of this loop segment. It is concluded that the high constitutive activity of the ghrelin receptor is dependent upon flexibility in the C-terminal segment...

  4. Real time markerless motion tracking using linked kinematic chains

    Science.gov (United States)

    Luck, Jason P.; Small, Daniel E.

    2007-08-14

    A markerless method is described for tracking the motion of subjects in a three dimensional environment using a model based on linked kinematic chains. The invention is suitable for tracking robotic, animal or human subjects in real-time using a single computer with inexpensive video equipment, and does not require the use of markers or specialized clothing. A simple model of rigid linked segments is constructed of the subject and tracked using three dimensional volumetric data collected by a multiple camera video imaging system. A physics based method is then used to compute forces to align the model with subsequent volumetric data sets in real-time. The method is able to handle occlusion of segments and accommodates joint limits, velocity constraints, and collision constraints and provides for error recovery. The method further provides for elimination of singularities in Jacobian based calculations, which has been problematic in alternative methods.

  5. Classical Nonminimal Lagrangians and Kinematic Tests of Special Relativity

    CERN Document Server

    Schreck, M

    2016-01-01

    This article gives a brief summary on recently obtained classical lagrangians for the nonminimal fermion sector of the Standard-Model Extension (SME). Such lagrangians are adequate descriptions of classical particles that are subject to a Lorentz-violating background field based on the SME. Explicitly, lagrangians were obtained for the leading nonminimal contributions of the m, a, c, e, and f coefficients. These results were then used to interpret classical, kinematic tests of Special Relativity in the framework of the nonminimal SME. This led to new constraints on certain nonminimal controlling coefficients. Although the experiments were very sophisticated in the era when they were carried out, their sensitivities for detecting Lorentz violation were still far away from the Planck scale. Obtaining the novel constraints can be considered as a proof-of-principle demonstrating the applicability of the classical lagrangians computed.

  6. Are static and dynamic kinematics comparable after total knee arthroplasty?

    Science.gov (United States)

    Saevarsson, Stefan K; Romeo, Carolina I; Anglin, Carolyn

    2013-04-05

    Knee kinematics provide information about how the femoral, tibial and patellar bones or prosthetic components move relative to each other. Accurate knowledge of kinematics is valuable for implant design, comparisons between designs or surgical techniques, and to identify differences between patients with good and poor outcomes. Both static and dynamic imaging techniques have been used to evaluate kinematics. In general, static imaging is used to capture better quality images or to capture views that cannot be acquired by dynamic imaging, whereas dynamic imaging is used to capture real-life movements. How well static kinematics represent dynamic kinematics is subject to frequent debate and has not been adequately addressed, especially after total knee arthroplasty (TKA). We compared the static and dynamic weightbearing kinematics of 10 female subjects after TKA. Using the same clinical scanner for both methods, static images were taken using our standard protocol, sequential-biplane radiographs at multiple flexion angles, as well as with dynamic video fluoroscopy during a step up activity. The static method can reliably measure all 12 degrees of freedom (DOF) after TKA, however only seven were compared due to the poorer out-of-plane reliability in the single-plane dynamic imaging. No differences were found between the static and dynamic kinematics for nine out of ten subjects. For one subject, however, a difference of 5-8° in internal/external tibial rotation was found. The research question, study purpose and the advantages and disadvantages of each method need to be considered when determining which imaging method to use.

  7. Multi-joint movements with reversal in Parkinson's disease: Kinematics and electromyography.

    Science.gov (United States)

    Sande de Souza, Luciane Aparecida Pascucci; Dionísio, Valdeci Carlos; Almeida, Gil Lúcio

    2011-04-01

    Subjects with Parkinson's disease (PD) presented difficulties in the performance of multi-joint movements. The purpose of the study was to determine whether the slowness of such movements was caused by the generation of non-linear trajectories and/or by a reduction or a deficit in the modulation of EMG activity. Nine healthy subjects and 10 subjects with PD performed multi-joint movements involving elbow and shoulder with reversal towards three targets in the sagittal plane without any constraint. The movement kinematics were calculated using X and Y coordinates of the markers positioned on the joints. EMG signals were recorded for the muscles related to these movements. The results revealed that subjects with PD presented a lower linear speed and the differences between them and healthy subjects increased with target distance. The trajectory was found to be linear and both groups of subjects had few errors in the targets despite the slower muscle activity in subjects with PD. Another interesting finding was the EMG pattern of subjects with PD. They showed a difficulty in modulating the activity of agonists and antagonists during the different movement phases. The low speed movements of PD subjects were attributable to the low EMG activity and difficulty in modulating the bursts of muscle activity.

  8. Reproducibility of 3D kinematics and surface electromyography measurements of mastication

    NARCIS (Netherlands)

    Remijn, L.; Groen, B.E.; Speyer, R.; Limbeek, J. van; Sanden, M.W. van der

    2016-01-01

    The aim of this study was to determine the measurement reproducibility for a procedure evaluating the mastication process and to estimate the smallest detectable differences of 3D kinematic and surface electromyography (sEMG) variables. Kinematics of mandible movements and sEMG activity of the masti

  9. Kinematic characteristics of postural control during reaching in preterm children with cerebral palsy

    NARCIS (Netherlands)

    Van Der Heide, JC; Folk, JM; Otten, B; Stremmelaar, E; Hadders-Algra, M

    2005-01-01

    The relationships between kinematic characteristics of sitting posture during reaching movements of the dominant arm and I) the kinematics of the reaching movement itself and 2) functional performance during daily life activities (PEDI) were assessed in 51 sitting preterm children with cerebral pals

  10. Kinematics of Saturn's spokes

    Science.gov (United States)

    Gruen, E.; Garneau, G. W.; Terrile, R. J.; Johnson, T. V.; Morfill, G. E.

    1984-01-01

    Voyager 2 images of Saturn's rings have been analyzed for spoke activity. More than 80 and 40 different spokes have been measured at the morning and at the evening ansa, respectively. Higher rate of spoke formation has been found at 145 + or 15 deg SLS and at 305 + or - 15 deg SLS which persisted for at least 3 Saturn revolutions. Higher spoke activity (formation and growth in width) by more than a factor 3 has been observed over the nightside hemisphere of Saturn than over the dayside hemisphere. The age distribution (i.e., time from radial formation until observation, assuming Keplerian shear) of the leading (old) edges of spokes has its maximum at approximately 9,000 s and 6,000 s for spokes observed at the morning ansa and at the evening ansa, respectively. The highest spoke age observed is approximately 20,000 s.

  11. Algebraic analysis of kinematics of multibody systems

    Directory of Open Access Journals (Sweden)

    S. Piipponen

    2013-02-01

    Full Text Available The constructive commutative algebra is very useful in the kinematical analysis of the mechanisms because a large class of systems can be described using polynomial equations. We show that one can analyze quite complicated systems using a sort of divide and conquer strategy to decompose the system, and hence the configuration space, into simpler parts. The key observation is that it seems that typically systems indeed have a lot of distinct components, but usually only one of them is physically relevant. Hence if one finds the equations describing the component of interest the analysis of this system can be surprisingly simple compared to the original system. In particular typically the possible singularities of the original system disappear when one restricts the attention to the relevant component. On the technical side we show that some basic constraints used to define joints in 3 dimensional mechanisms can be decomposed to simpler parts. This has significant practical consequences because using these fundamental decompositions when writing the equations for complicated mechanisms decreases dramatically the complexity of the required computations.

  12. Theoretical and Numerical Experiences on a Test Rig for Active Vibration Control of Mechanical Systems with Moving Constraints

    Directory of Open Access Journals (Sweden)

    M. Rinchi

    2004-01-01

    Full Text Available Active control of vibrations in mechanical systems has recently benefited of the remarkable development of robust control techniques. These control techniques are able to guarantee performances in spite of unavoidable modeling errors. They have been successfully codified and implemented for vibrating structures whose uncertain parameters could be assumed to be time-invariant. Unfortunately a wide class of mechanical systems, such as machine tools with carriage motion realized by a ball-screw, are characterized by time varying modal parameters. The focus of this paper is on modeling and controlling the vibrations of such systems. A test rig for active vibration control is presented. An analytical model of the test rig is synthesized starting by design data. Through experimental modal analysis, parametric identification and updating procedures, the model has been refined and a control system has been synthesized.

  13. SUMOylation Is an Inhibitory Constraint that Regulates the Prion-like Aggregation and Activity of CPEB3

    Directory of Open Access Journals (Sweden)

    Bettina Drisaldi

    2015-06-01

    Full Text Available Protein synthesis is crucial for the maintenance of long-term-memory-related synaptic plasticity. The prion-like cytoplasmic polyadenylation element-binding protein 3 (CPEB3 regulates the translation of several mRNAs important for long-term synaptic plasticity in the hippocampus. Here, we provide evidence that the prion-like aggregation and activity of CPEB3 is controlled by SUMOylation. In the basal state, CPEB3 is a repressor and is soluble. Under these circumstances, CPEB3 is SUMOylated in hippocampal neurons both in vitro and in vivo. Following neuronal stimulation, CPEB3 is converted into an active form that promotes the translation of target mRNAs, and this is associated with a decrease of SUMOylation and an increase of aggregation. A chimeric CPEB3 protein fused to SUMO cannot form aggregates and cannot activate the translation of target mRNAs. These findings suggest a model whereby SUMO regulates translation of mRNAs and structural synaptic plasticity by modulating the aggregation of the prion-like protein CPEB3.

  14. The Soft Cumulative Constraint

    CERN Document Server

    Petit, Thierry

    2009-01-01

    This research report presents an extension of Cumulative of Choco constraint solver, which is useful to encode over-constrained cumulative problems. This new global constraint uses sweep and task interval violation-based algorithms.

  15. Possibility of prediction of strong seismic events in the Middle Odra Fault Zone based on variations of kinematic activity of the Świebodzice Depression

    Science.gov (United States)

    Kaczorowski, Marek; Kasza, Damian; Zdunek, Ryszard; Wronowski, Roman; Szczerbowski, Zbigniew

    2017-04-01

    Książ Geodynamic Laboratory of Space Research Centre is located in the Świebodzice Depression unit. The laboratory was built inside underground corridors made in the castle hill about 50 m below surface. The main instruments which provide us most of information about tectonic activity of Świebodzice Depression are two long water-tubes tiltmeters 65 and 92 meters long (WT). The WT are situated on several rocky blocks which motions provided tectonic signals to WT. The instruments register numerous irregularly occurred epochs of water levels variations in hydrodynamic systems of magnitudes exceeding tidal signals dozens or so times. These observations are interpreted as result of tiltings of foundation and vertical motions of rock blocks. Signals of tiltings of foundation and vertical motions are superposed by the WT registration system. The resultant signals from four channels of WT were defined by us as tectonic activity functions of the massif. Variations of the tectonic activity functions as well as their first derivatives were compared with the seismic activity in Fore-Sudetic Monocline. We found correlation in time and amplitudes domains between extremes and inflection points of the first derivative of the tectonic activity function and the seismic events in the Middle Odra Fault Zone of the Fore-Sudetic Monocline. High correlation concerns only the strong earthquakes the energies of which were larger than 4 MJ. Almost all the high energy seismic events from 2005 to 2015 took place in surroundings of minima, maxima or inflection points of tectonic activity functions when first derivatives were close to zero. In the epochs of large absolute values of amplitudes of first derivatives i.e. during high tectonic activity of Świebodzice Depression, the strong energy earthquakes never happened. The observation shows that the origin of the low and high energy earthquakes is different. The high energy earthquakes are produced by natural tectonic activity, while the

  16. Exploring MaNGA's kinematic maps

    Science.gov (United States)

    Weijmans, Anne-Marie; MaNGA Team

    2016-01-01

    Different galaxy formation processes leave different imprints on the gas and stellar kinematic patterns for a galaxy. With MaNGA, we now have after one year of observations an unprecedented sample of 1400 nearby galaxies for which we can study gas and stellar kinematics in much detail, based on integral-field spectroscopy. We are measuring kinematic quantities such as LambdaR (angular momentum) and their (possible) correlations with other galaxy properties such as mass, morphology and environment. By quantifying the kinematic (sub)structures in velocity and dispersion maps, we will construct a kinematic galaxy classification that can be linked to their formation processes.

  17. Late Quaternary tectonics and active ground deformation in the Catania urban area (eastern Sicily): New constraints from a geological investigation

    Science.gov (United States)

    Catalano, Stefano; Pavano, Francesco; Romagnoli, Gino; Tortorici, Giuseppe

    2017-08-01

    New surface and subsurface geological data on the Catania urban area, in eastern Sicily, are here illustrated by a detailed geological map of the city and by four significant cross-sections. Our study aims at defining the prolongation of the principal regional Late Quaternary tectonic features, beneath the city. The resulting geometry of the investigated structures completes the tectonic pictures of two different stages of deformation. The earlier structural association, ranging in age from 600 to 125 ka, consists of a transpressive dextral belt that include E-W oblique thrust ramp, located to the south and the north of the city respectively, connected by a wide NE-SW oriented anticline crossing the urban area. The younger structural association developed since the Late Pleistocene and includes a set of ENE-trending folds that originated at the hangingwall of a main thrust ramp running just beneath the old town (Catania Thrust Ramp). These contractional features have been active during the last 60 ka and their geometry is consistent with the active ground deformation observed by the available geodetic data (GPS vectors and DInSAR analyses). The entire set of the recent structures are bordered to the north by a dextral transfer zone, reactivating part of the previous E-W alignment, that now represents the tectonic boundary with the Mt. Etna Volcano transtensional domain. Our data suggest that the Catania Thrust Ramp could play a main role in the active deformation pattern of the region, thus representing a potential seismotectonic feature to be carefully investigated for the re-evaluation of the seismic hazard of the area.

  18. Kinematic modeling, analysis and test on a quiet spherical pump

    Science.gov (United States)

    Guan, Dong; Wu, Jiu Hui; Jing, Li; Hilton, Harry H.; Lu, Kuan

    2016-11-01

    In this paper, design and modeling of a novel spherical pump are undertaken. Both sound and vibration properties of the pump are studied experimentally. The working mechanism of the pump is analyzed firstly, and then structural design and kinematic theory are modeled by using two different coordinate systems. Nonlinear kinematic constraint equations are developed using a generalized computational method for spatial kinematic analysis. These equations are solved to yield the displacement, angular velocity and acceleration properties of motion parts with different structural parameters. Sound and vibration characteristics of the spherical pump and traditional solenoid pumps are studied experimentally at different rotating speeds of 1000, 1500, 2000, 2500 and 3000 rev/min. Results indicate that sound pressure levels of the proposed spherical are reduced to 40.7 dB(A), which are 11.1 dB(A) lower than the traditional solenoid pump's 51.8 dB(A) at the rated operating conditions. The sound spectra are analyzed in detail in order to investigate the causes, which are structural pattern and working mechanisms. The proposed spherical pump has many advantages and can be utilized as a substitute for other pumps in some special fields, such as hospital facilities and household appliances.

  19. Composing constraint solvers

    NARCIS (Netherlands)

    Zoeteweij, P.

    2005-01-01

    Composing constraint solvers based on tree search and constraint propagation through generic iteration leads to efficient and flexible constraint solvers. This was demonstrated using OpenSolver, an abstract branch-and-propagate tree search engine that supports a wide range of relevant solver configu

  20. Constraints from atmospheric CO2 and satellite-based vegetation activity observations on current land carbon cycle trends

    Directory of Open Access Journals (Sweden)

    S. Zaehle

    2012-11-01

    Full Text Available Terrestrial ecosystem models used for Earth system modelling show a significant divergence in future patterns of ecosystem processes, in particular carbon exchanges, despite a seemingly common behaviour for the contemporary period. An in-depth evaluation of these models is hence of high importance to achieve a better understanding of the reasons for this disagreement. Here, we develop an extension for existing benchmarking systems by making use of the complementary information contained in the observational records of atmospheric CO2 and remotely-sensed vegetation activity to provide a firm set of diagnostics of ecosystem responses to climate variability in the last 30 yr at different temporal and spatial scales. The selection of observational characteristics (traits specifically considers the robustness of information given the uncertainties in both data and evaluation analysis. In addition, we provide a baseline benchmark, a minimum test that the model under consideration has to pass, to provide a more objective, quantitative evaluation framework. The benchmarking strategy can be used for any land surface model, either driven by observed meteorology or coupled to a climate model. We apply this framework to evaluate the offline version of the MPI-Earth system model's land surface scheme JSBACH. We demonstrate that the complementary use of atmospheric CO2 and satellite based vegetation activity data allows to pinpoint specific model failures that would not be possible by the sole use of atmospheric CO2 observations.

  1. Kinematic models of lower limb joints for musculo-skeletal modelling and optimization in gait analysis.

    Science.gov (United States)

    Leardini, Alberto; Belvedere, Claudio; Nardini, Fabrizio; Sancisi, Nicola; Conconi, Michele; Parenti-Castelli, Vincenzo

    2017-05-22

    Kinematic models of lower limb joints have several potential applications in musculoskeletal modelling of the locomotion apparatus, including the reproduction of the natural joint motion. These models have recently revealed their value also for in vivo motion analysis experiments, where the soft-tissue artefact is a critical known problem. This arises at the interface between the skin markers and the underlying bone, and can be reduced by defining multibody kinematic models of the lower limb and by running optimization processes aimed at obtaining estimates of position and orientation of relevant bones. With respect to standard methods based on the separate optimization of each single body segment, this technique makes it also possible to respect joint kinematic constraints. Whereas the hip joint is traditionally assumed as a 3 degrees of freedom ball and socket articulation, many previous studies have proposed a number of different kinematic models for the knee and ankle joints. Some of these are rigid, while others have compliant elements. Some models have clear anatomical correspondences and include real joint constraints; other models are more kinematically oriented, these being mainly aimed at reproducing joint kinematics. This paper provides a critical review of the kinematic models reported in literature for the major lower limb joints and used for the reduction of soft-tissue artefact. Advantages and disadvantages of these models are discussed, considering their anatomical significance, accuracy of predictions, computational costs, feasibility of personalization, and other features. Their use in the optimization process is also addressed, both in normal and pathological subjects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Submarine explosive activity and ocean noise generation at Monowai Volcano, Kermadec Arc: constraints from hydroacoustic T-waves

    Science.gov (United States)

    Grevemeyer, Ingo; Metz, Dirk; Watts, Anthony

    2016-04-01

    Submarine volcanic activity is difficult to detect, because eruptions at depth are strongly attenuated by seawater. With increasing depth the ambient water pressure increases and limits the expansion of gas and steam such that volcanic eruptions tend to be less violent and less explosive with depth. Furthermore, the thermal conductivity and heat capacity of water causes rapid cooling of ejected products and hence erupted magma cools much more quickly than during subaerial eruptions. Therefore, reports on submarine volcanism are restricted to those sites where erupted products - like the presence of pumice rafts, gas bubbling on the sea surface, and local seawater colour changes - reach the sea surface. However, eruptions cause sound waves that travel over far distances through the Sound-Fixing-And-Ranging (SOFAR) channel, so called T-waves. Seismic networks in French Polynesia recorded T-waves since the 1980's that originated at Monowai Volcano, Kermadec Arc, and were attributed to episodic growth and collapse events. Repeated swath-mapping campaigns conducted between 1998 and 2011 confirm that Monowai volcano is a highly dynamic volcano. In July of 2007 a network of ocean-bottom-seismometers (OBS) and hydrophones was deployed and recovered at the end of January 2008. The instruments were located just to the east of Monowai between latitude 25°45'S and 27°30'S. The 23 OBS were placed over the fore-arc and on the incoming subducting plate to obtain local seismicity associated with plate bending and coupling of the subduction megathrust. However, we recognized additional non-seismic sleuths in the recordings. Events were best seen in 1 Hz high-pass filtered hydrophone records and were identified as T-waves. The term T-wave is generally used for waves travelling through the SOFAR channel over large distances. In our case, however, they were also detected on station down to ~8000 m, suggesting that waves on the sea-bed station were direct waves caused by explosive

  3. Constraints on Alpine hydrothermal activity and deformation from U-Th-Pb dating of cleft monazite and xenotime (Western Alps)

    Science.gov (United States)

    Grand'Homme, Alexis; Janots, Emilie; Bosse, Valerie; Seydoux-Guillaume, Anne-Magali; De Ascencao, Roger

    2016-04-01

    In this large-scale regional study, age of hydrothermal monazite (and xenotime) precipitation has been investigated through in-situ U-Th-Pb dating of crystals collected in 11 clefts (veins) taken in the internal and external massifs (Western Alps). The investigated clefts are composed of quartz, chlorite (± epidote), albite and millimetric accessory minerals (monazite, apatite, xenotime, anatase, rutile). Prior to dating, cleft monazite composition was thoroughly studied to reveal potential zoning. In-situ dating through different compositional domains of single monazite crystal yields well-resolved Th-Pb ages (typically with 0.1-0.3 Ma resolution) indicating for growth episodes with short duration. Comparison of U-Pb and Th-Pb dating indicates that the U-Pb systematics appears successful to date cleft monazite with low Th/U ratio (typically hand, monazite dating in the Argentera (20.6 ± 0.3 Ma) confirms for the regional diachronism observed from South to the North of the ECM in the Western Alps. First ages were here obtained for the hydrothermal activity of the internal massifs of the Western Alps. As expected from other (thermo)chronometers, hydrothermal activity in the Internal Alpine domains (Briançonnais) is older than in the ECM. In the Briançonnais zone, monazite age at 32.1 ± 0.2 Ma coincides with the exhumation along the penninic front. In the second cleft, monazite age at 23.3 ± 0.2 Ma is more complex to attribute to a specific deformation stage.

  4. Methodological constraints in interpreting serum paraoxonase-1 activity measurements: an example from a study in HIV-infected patients

    Directory of Open Access Journals (Sweden)

    Joven Jorge

    2010-03-01

    Full Text Available Abstract Background Paraoxonase-1 (PON1 is an antioxidant enzyme that attenuates the production of the monocyte chemoattractant protein-1 (MCP-1 in vitro. Although oxidation and inflammation are closely related processes, the association between PON1 and MCP-1 has not been completely characterised due, probably, to that the current use of synthetic substrates for PON1 measurement limits the interpretation of the data. In the present study, we explored the relationships between the circulating levels of PON1 and MCP-1 in human immunodeficiency virus-infected patients in relation to the multifunctional capabilities of PON1. Methods We measured selected variables in 227 patients and in a control group of 409 participants. Serum PON1 esterase and lactonase activities were measured as the rates of hydrolysis of paraoxon and of 5-(thiobutyl-butyrolactone, respectively. Oxidised LDL and MCP-1 concentrations were determined by enzyme-linked immunosorbent assay. High-density lipoproteins cholesterol, apolipoprotein A-I, and C-reactive protein concentrations were measured by standard automated methods. Results There were significant relationships between PON1 activity and several indices of oxidation and inflammation in control subjects and in infected patients. However, these relationships varied not only with disease status but also on the type of substrate used for PON1 measurement. Conclusion The present study is a cautionary tale highlighting that results of clinical studies on PON1 may vary depending on the methods used as well as the disease studied. Until more specific methods using physiologically-akin substrates are developed for PON1 measurement, we suggest the simultaneous employment of at least two different substrates in order to improve the reliability of the results obtained.

  5. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  6. Kinematic Fitting of Detached Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mattione, Paul [Rice Univ., Houston, TX (United States)

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  7. Measurement of reed valve kinematics

    Science.gov (United States)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  8. Sex Differences in Tibiocalcaneal Kinematics

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2014-08-01

    Full Text Available Purpose. Female runners typically suffer more from chronic running injuries than age-matched males, although the exact biome-chanical mechanisms behind the increased susceptibility of female runners are unknown. This study aimed to compare sex differences in tibiocalcaneal kinematics during the stance phase of running. Methods. Twenty male and twenty female participants ran at 4.0 m · s–1. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using independent samples t tests. Results. Peak eversion and tibial internal rotation angles were shown to be significantly greater in female runners. Conclusions. based on these observations, it was determined that female runners may be at increased risk from chronic injury development in relation to excessive tibiocalcaneal motions in the coronal and transverse planes.

  9. Geochemical constraints on the diversity and activity of H2 -oxidizing microorganisms in diffuse hydrothermal fluids from a basalt- and an ultramafic-hosted vent.

    Science.gov (United States)

    Perner, Mirjam; Petersen, Jillian M; Zielinski, Frank; Gennerich, Hans-Hermann; Seifert, Richard

    2010-10-01

    Mixing processes of reduced hydrothermal fluids with oxygenated seawater and fluid-rock reactions contribute to the chemical signatures of diffuse venting and likely determine the geochemical constraints on microbial life. We examined the influence of fluid chemistry on microbial diversity and activity by sampling diffuse fluids emanating through mussel beds at two contrasting hydrothermal vents. The H(2) concentration was very low at the basalt-hosted Clueless site, and mixing models suggest O(2) availability throughout much of the habitat. In contrast, effluents from the ultramafic-hosted Quest site were considerably enriched in H(2) , while O(2) is likely limited to the mussel layer. Only two different hydrogenase genes were identified in clone libraries from the H(2) -poor Clueless fluids, but these fluids exhibited the highest H(2) uptake rates in H(2) -spiked incubations (oxic conditions, at 18 °C). In contrast, a phylogenetically diverse H(2) -oxidizing potential was associated with distinct thermal conditions in the H(2) -rich Quest fluids, but under oxic conditions, H(2) uptake rates were extremely low. Significant stimulation of CO(2) fixation rates by H(2) addition was solely illustrated in Quest incubations (P-value <0.02), but only in conjunction with anoxic conditions (at 18 °C). We conclude that the factors contributing toward differences in the diversity and activity of H(2) oxidizers at these sites include H(2) and O(2) availability.

  10. Activation and application of an obligatory phonotactic constraint in German during automatic speech processing is revealed by human event-related potentials.

    Science.gov (United States)

    Steinberg, Johanna; Truckenbrodt, Hubert; Jacobsen, Thomas

    2010-07-01

    In auditory speech processing, implicit linguistic knowledge is activated and applied on phonetic and segment-related phonological processing level even if the perceived sound sequence is outside the focus of attention. In this study, the effects of language-specific phonotactic restrictions on pre-attentive auditory speech processing were investigated, using the Mismatch Negativity component of the human event-related brain potential. In German grammar, the distribution of the velar and the palatal dorsal fricative is limited by an obligatory phonotactic constraint, Dorsal Fricative Assimilation, which demands that a vowel and a following dorsal fricative must have the same specifications for articulatory backness. For passive oddball stimulation, we used three phonotactically correct VC syllables and one incorrect VC syllable, composed of the vowels [epsilon] and [open o] and the fricatives [ç] and []. Stimuli were contrasted pairwise in experimental oddball blocks in a way that they differed in regard to their respective vowel but shared the fricative. Additionally to the usual Mismatch Negativity which is attributable to the change of the initial vowel and which was elicited by all deviants, we observed a second negative deflection in the deviant ERP elicited by the phonotactically ill-formed syllable only. This negativity cannot be attributed to any acoustical or phonemic difference between standard and deviant, it rather reflects the effect of a phonotactic evaluation process after both sounds of the syllable were identified. Our finding suggests that implicit phonotactic knowledge is activated and applied even outside the focus of the participants' attention.

  11. Kinematics of the Danakil microplate

    OpenAIRE

    2002-01-01

    A refinement and extrapolation of recent motion estimates for the Danakilmicroplate, based on ancient kinematic indicators in the Afar region, describesthe evolution of a microplate in the continental realm. The Danakil horst is anelevated part of this microplate, exposing Precambrian basement within theAfar depression, site of the Nubia-Somalia-Arabia triple junction. We compareevidence for strike- or oblique-slip faults in data from the Afar depression andsouthern Red Sea to small circles a...

  12. Pythagoras Theorem and Relativistic Kinematics

    Science.gov (United States)

    Mulaj, Zenun; Dhoqina, Polikron

    2010-01-01

    In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.

  13. A kinematic comparison of alterations to knee and ankle angles from resting measures to active pedaling during a graded exercise protocol.

    Science.gov (United States)

    Peveler, Willard W; Shew, Brandy; Johnson, Samantha; Palmer, Thomas G

    2012-11-01

    Saddle height is one of the most researched areas of bike fit. The current accepted method for adjusting saddle height involves the use of a goniometer to adjust saddle height so that a knee angle between 25° and 35° is obtained. This measurement is taken while the cyclist maintains a static position with the pedal at the 6-o'-clock position. However, the act of pedaling is dynamic, and angles may alter during movement. The purpose of this study was to examine the alterations to knee and ankle angle occurring from static measures to active pedaling across intensities experienced by cyclists during a graded exercise protocol. Thirty-four recreational to highly trained cyclists were evaluated using 2D analysis of stationary position and 3 active levels (level 1, respiratory exchange ratio of 1.00, and max). Dependent measures were compared using repeated measures analysis of variance (p = 0.05). When examining the results, it is evident that significant alterations to pedal stroke occur from stationary measures to active pedaling and as intensity increases toward maximal. Plantar flexion increased when moving from stationary measures to active pedaling, which resulted in an increase in knee angle. Although still greater than stationary measures, less plantar flexion occurred at higher intensities when compared with lower intensity cycling. Less plantar flexion at higher intensities is most likely a result of application of a larger downward torque occurring because of greater power requirements at higher intensities. There appeared to be greater variability in angle when examining novice cyclists in relation to more experienced cyclists. Although stationary measures are where a bike fit session will begin, observation during the pedal cycle may be needed to fine-tune the riders' fit.

  14. Feasibility of differential quantification of 3D temporomandibular kinematics during various oral activities using a cone-beam computed tomography-based 3D fluoroscopic method

    Directory of Open Access Journals (Sweden)

    Chien-Chih Chen

    2013-06-01

    Conclusion: A new CBCT-based 3D fluoroscopic method was proposed and shown to be capable of quantitatively differentiating TMJ movement patterns among complicated functional activities. It also enabled a complete description of the rigid-body mandibular motion and descriptions of as many reference points as needed for future clinical applications. It will be helpful for dental practice and for a better understanding of the functions of the TMJ.

  15. Time-dependence between upper arm muscles activity during rapid movements: observation of the proportional effects predicted by the kinematic theory.

    Science.gov (United States)

    Plamondon, Réjean; Djioua, Moussa; Mathieu, Pierre A

    2013-10-01

    Rapid human movements can be assimilated to the output of a neuromuscular system with an impulse response modeled by a Delta-Lognormal equation. In such a model, the main assumption concerns the cumulative time delays of the response as it propagates toward the effector following a command. To verify the validity of this assumption, delays between bursts in electromyographic (EMG) signals of agonist and antagonist muscles activated during a rapid hand movement were investigated. Delays were measured between the surface EMG signals of six muscles of the upper limb during single rapid handwriting strokes. From EMG envelopes, regressions were obtained between the timing of the burst of activity produced by each monitored muscle. High correlation coefficients were obtained supporting the proportionality of the cumulative time delays, the basic hypothesis of the Delta-Lognormal model. A paradigm governing the sequence of muscle activities in a rapid movement could, in the long run, be useful for applications dealing with the analysis and synthesis of human movements.

  16. Kinematic Downsizing at z~2

    CERN Document Server

    Simons, Raymond C; Trump, Jonathan R; Weiner, Benjamin J; Heckman, Timothy M; Barro, Guillermo; Koo, David C; Guo, Yicheng; Pacifici, Camilla; Koekemoer, Anton; Stephens, Andrew W

    2016-01-01

    We present results from a survey of the internal kinematics of 49 star-forming galaxies at z$\\,\\sim\\,$2 in the CANDELS fields with the Keck/MOSFIRE spectrograph (SIGMA, Survey in the near-Infrared of Galaxies with Multiple position Angles). Kinematics (rotation velocity $V_{rot}$ and integrated gas velocity dispersion $\\sigma_g$) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z$\\,\\sim\\,$2, massive star-forming galaxies ($\\log\\,M_*/M_{\\odot}\\gtrsim10.2$) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of $V_{rot}/\\sigma_g$ which are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low mass galaxies ($\\log\\,M_*/M_{\\odot}\\lesssim10.2$) at this epoch are still in the early stages of disk...

  17. Kinematic Characteristics of 3-UPU Parallel Manipulator in Singularity and Its Application

    Directory of Open Access Journals (Sweden)

    Peng Binbin

    2011-09-01

    Full Text Available This paper focuses on the kinematic characteristics of the 3‐UPU (universal‐prismatic‐ universal parallel manipulator in one of singular configurations. The motion of the moving platform is analyzed by changing the layout of the universal joints. A layout of universal joints in the singular configuration is discussed in detail by deriving the kinematic and constraint equations. Solving the equations, the kinematic characteristics in such case is obtained. At the same time the kinematic characteristics is simulated by the commercial software and the results of the simulation verify it. Based on the kinematics characteristics of it, the application of the singular configuration is presented. And a compound limb which can translate freely along a circular path is presented. Finally, the some new 2‐DOF (degree of freedom planar parallel translating manipulators whose orientation can remain constant are put forward by the compound limb. The passive joints of the new 2‐DOF planar parallel translating manipulators are universal joint and the struts of it do not bear the bending moment. It gives the planar parallel manipulator a good architecture to resist the force which is perpendicular to the kinematics plane.

  18. Analysis and experimental kinematics of a skid-steering wheeled robot based on a laser scanner sensor.

    Science.gov (United States)

    Wang, Tianmiao; Wu, Yao; Liang, Jianhong; Han, Chenhao; Chen, Jiao; Zhao, Qiteng

    2015-04-24

    Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR) of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable and robot speed ), including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model's stationary response for the vehicle shows a qualitative relationship for the specified parameters and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient and two physical factors is studied, i.e., the radius of the path curvature and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid-steering robot.

  19. Feedback between erosion and active deformation: geomorphic constraints from the frontal Jura fold-and-thrust belt (eastern France)

    Science.gov (United States)

    Madritsch, Herfried; Fabbri, Olivier; Hagedorn, Eva-Marie; Preusser, Frank; Schmid, Stefan M.; Ziegler, Peter A.

    2010-10-01

    A regional tectono-geomorphic analysis indicates a Pliocene to recent rock uplift of the outermost segment of the Jura fold-and-thrust belt, which spatially coincides with the intra-continental Rhine-Bresse Transfer Zone. Elevated remnants of the partly eroded Middle Pliocene Sundgau-Forêt de Chaux Gravels identified by heavy mineral analyses allow for a paleo-topographic reconstruction that yields minimum regional Latest Pliocene to recent rock uplift rates of 0.05 ± 0.02 mm/year. This uplift also affected the Pleistocene evolution of the Ognon and Doubs drainage basins and is interpreted as being tectonically controlled. While the Ognon River was deflected from the uplifted region the Doubs deeply incised into it. Focused incision of the Doubs possibly sustained ongoing deformation along anticlines which were initiated during the Neogene evolution of the thin-skinned Jura fold-and-thrust belt. At present, this erosion-related active deformation is taking place synchronously with thick-skinned tectonics, controlling the inversion of the Rhine-Bresse Transfer Zone. This suggests local decoupling between seismogenic basement faulting and erosion-related deformation of the Mesozoic cover sequences.

  20. Kinematic landslide monitoring with Kalman filtering

    Directory of Open Access Journals (Sweden)

    M. Acar

    2008-03-01

    Full Text Available Landslides are serious geologic disasters that threat human life and property in every country. In addition, landslides are one of the most important natural phenomena, which directly or indirectly affect countries' economy. Turkey is also the country that is under the threat of landslides. Landslides frequently occur in all of the Black Sea region as well as in many parts of Marmara, East Anatolia, and Mediterranean regions. Since these landslides resulted in destruction, they are ranked as the second important natural phenomenon that comes after earthquake in Turkey. In recent years several landslides happened after heavy rains and the resulting floods. This makes the landslide monitoring and mitigation techniques an important study subject for the related professional disciplines in Turkey. The investigations on surface deformations are conducted to define the boundaries of the landslide, size, level of activity and direction(s of the movement, and to determine individual moving blocks of the main slide.

    This study focuses on the use of a kinematic deformation analysis based on Kalman Filtering at a landslide area near Istanbul. Kinematic deformation analysis has been applied in a landslide area, which is located to the north of Istanbul city. Positional data were collected using GPS technique. As part of the study, conventional static deformation analysis methodology has also been applied on the same data. The results and comparisons are discussed in this paper.

  1. On Testing Constraint Programs

    CERN Document Server

    Lazaar, Nadjib; Yahia, Lebbah

    2010-01-01

    The success of several constraint-based modeling languages such as OPL, ZINC, or COMET, appeals for better software engineering practices, particularly in the testing phase. This paper introduces a testing framework enabling automated test case generation for constraint programming. We propose a general framework of constraint program development which supposes that a first declarative and simple constraint model is available from the problem specifications analysis. Then, this model is refined using classical techniques such as constraint reformulation, surrogate and global constraint addition, or symmetry-breaking to form an improved constraint model that must be thoroughly tested before being used to address real-sized problems. We think that most of the faults are introduced in this refinement step and propose a process which takes the first declarative model as an oracle for detecting non-conformities. We derive practical test purposes from this process to generate automatically test data that exhibit no...

  2. Effect of therapist-based constraint-induced therapy at home on motor control, motor performance and daily function in children with cerebral palsy: a randomized controlled study.

    Science.gov (United States)

    Chen, Chia-ling; Kang, Lin-ju; Hong, Wei-Hsien; Chen, Fei-Chuan; Chen, Hsieh-Ching; Wu, Ching-yi

    2013-03-01

    To determine the effect of therapist-based constraint-induced therapy at home on motor performance, daily function and reaching control for children with cerebral palsy. A single-blinded, randomized controlled trial. Forty-seven children (23 boys; 24 girls) with unilateral cerebral palsy, aged 6-12 years, were randomized to constraint-induced therapy (n = 24) or traditional rehabilitation (n = 23). Constraint-induced therapy involved intensive functional training of the more affected arm while the less affected arm was restrained. Traditional rehabilitation involved functional unilateral and bilateral arm training. Both groups received individualized therapist-based interventions at home for 3.5-4 hours/day, two days a week for four weeks. Motor performance and daily function were measured by the Peabody Developmental Motor Scale, Second Edition and the Pediatric Motor Activity Log. Reaching control was assessed by the kinematics of reaction time, movement time, movement unit and peak velocity. There were larger effects in favour of constraint-induced therapy on motor performance, daily function, and some aspects of reaching control compared with traditional rehabilitation. Children receiving constraint-induced therapy demonstrated higher scores for Peabody Developmental Motor Scale, Second Edition - Grasping (pretest mean ± SD, 39.9 ± 3.1; posttest, 44.1 ± 2.8; P Motor Activity Log (pretest, 1.8 ± 0.3; posttest, 2.5 ± 0.3; P control of reaching in children with unilateral cerebral palsy than traditional rehabilitation.

  3. Effect of auditory constraints on motor performance depends on stage of recovery post-stroke.

    Science.gov (United States)

    Aluru, Viswanath; Lu, Ying; Leung, Alan; Verghese, Joe; Raghavan, Preeti

    2014-01-01

    In order to develop evidence-based rehabilitation protocols post-stroke, one must first reconcile the vast heterogeneity in the post-stroke population and develop protocols to facilitate motor learning in the various subgroups. The main purpose of this study is to show that auditory constraints interact with the stage of recovery post-stroke to influence motor learning. We characterized the stages of upper limb recovery using task-based kinematic measures in 20 subjects with chronic hemiparesis. We used a bimanual wrist extension task, performed with a custom-made wrist trainer, to facilitate learning of wrist extension in the paretic hand under four auditory conditions: (1) without auditory cueing; (2) to non-musical happy sounds; (3) to self-selected music; and (4) to a metronome beat set at a comfortable tempo. Two bimanual trials (15 s each) were followed by one unimanual trial with the paretic hand over six cycles under each condition. Clinical metrics, wrist and arm kinematics, and electromyographic activity were recorded. Hierarchical cluster analysis with the Mahalanobis metric based on baseline speed and extent of wrist movement stratified subjects into three distinct groups, which reflected their stage of recovery: spastic paresis, spastic co-contraction, and minimal paresis. In spastic paresis, the metronome beat increased wrist extension, but also increased muscle co-activation across the wrist. In contrast, in spastic co-contraction, no auditory stimulation increased wrist extension and reduced co-activation. In minimal paresis, wrist extension did not improve under any condition. The results suggest that auditory task constraints interact with stage of recovery during motor learning after stroke, perhaps due to recruitment of distinct neural substrates over the course of recovery. The findings advance our understanding of the mechanisms of progression of motor recovery and lay the foundation for personalized treatment algorithms post-stroke.

  4. Differences in unilateral chest press muscle activation and kinematics on a stable versus unstable surface while holding one versus two dumbbells.

    Science.gov (United States)

    Patterson, Jeffrey M; Vigotsky, Andrew D; Oppenheimer, Nicole E; Feser, Erin H

    2015-01-01

    Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell rather than two and lifting on the COR bench compared to a flat bench. Electromyography (EMG) amplitudes of the pectoralis major, middle trapezius, external oblique, and internal oblique were recorded and compared. Differences in range of motion (ROM) were evaluated by measuring an angular representation of the shoulder complex. Four separate conditions of unilateral bench press were tested while lifting on a: flat bench with one dumbbell, flat bench with two dumbbells, COR Bench with one dumbbell, and COR Bench with two dumbbells. The results imply that there are no differences in EMG amplitude or ROM between the COR bench and traditional bench. However, greater ROM was found to be utilized in the single dumbbell condition, both in the COR bench and the flat bench.

  5. Differences in unilateral chest press muscle activation and kinematics on a stable versus unstable surface while holding one versus two dumbbells

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Patterson

    2015-10-01

    Full Text Available Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell rather than two and lifting on the COR bench compared to a flat bench. Electromyography (EMG amplitudes of the pectoralis major, middle trapezius, external oblique, and internal oblique were recorded and compared. Differences in range of motion (ROM were evaluated by measuring an angular representation of the shoulder complex. Four separate conditions of unilateral bench press were tested while lifting on a: flat bench with one dumbbell, flat bench with two dumbbells, COR Bench with one dumbbell, and COR Bench with two dumbbells. The results imply that there are no differences in EMG amplitude or ROM between the COR bench and traditional bench. However, greater ROM was found to be utilized in the single dumbbell condition, both in the COR bench and the flat bench.

  6. Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Jet Kinematics from Bimonthly Monitoring with the Very Long Baseline Array

    CERN Document Server

    Jorstad, S G; Lister, M L; Stirling, A M; Cawthorne, T V; Gear, W K; Gómez, J L; Stevens, J A; Smith, P S; Forster, J R; Gabuzda, D C; Robson, E I; Jorstad, Svetlana G.; Marscher, Alan P.; Lister, Matthew L.; Stirling, Alastair M.; Cawthorne, Timothy V.; Gear, Walter K.; Gomez, Jose L.; Stevens, Jason A.; Smith, Paul S.; Forster, James R.; Gabuzda, Denise C.

    2005-01-01

    We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7 mm at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3 mm, 1.35/0.85 mm, and optical wavelengths. Here we analyze the 7 mm images to define the properties of the jets of two radio galaxies, five BL Lac objects, and eight quasars on angular scales $\\gtrsim 0.1$ milliarcseconds. We determine the apparent velocities of 109 features in the jets; for many of the features we derive Doppler factors using a new method based on comparison of timescale of decline in flux density with the light-travel time across the emitting region. This allows us to estimate the Lorentz factors, intrinsic brightness temperatures, and viewing angles of 77 superluminal knots, as well as the opening angle of the jet for each source. We analyze the derived physical parameters of the jets. In nine sources we detect statistically m...

  7. A Concept for Extending the Applicability of Constraint-Induced Movement Therapy through Motor Cortex Activity Feedback Using a Neural Prosthesis

    Directory of Open Access Journals (Sweden)

    Tomas E. Ward

    2007-01-01

    Full Text Available This paper describes a concept for the extension of constraint-induced movement therapy (CIMT through the use of feedback of primary motor cortex activity. CIMT requires residual movement to act as a source of feedback to the patient, thus preventing its application to those with no perceptible movement. It is proposed in this paper that it is possible to provide feedback of the motor cortex effort to the patient by measurement with near infrared spectroscopy (NIRS. Significant changes in such effort may be used to drive rehabilitative robotic actuators, for example. This may provide a possible avenue for extending CIMT to patients hitherto excluded as a result of severity of condition. In support of such a paradigm, this paper details the current status of CIMT and related attempts to extend rehabilitation therapy through the application of technology. An introduction to the relevant haemodynamics is given including a description of the basic technology behind a suitable NIRS system. An illustration of the proposed therapy is described using a simple NIRS system driving a robotic arm during simple upper-limb unilateral isometric contraction exercises with healthy subjects.

  8. Constraints meet concurrency

    CERN Document Server

    Mauro, Jacopo

    2014-01-01

    This book describes the benefits that emerge when the fields of constraint programming and concurrency meet. On the one hand, constraints can be used in concurrency theory to increase the conciseness and the expressive power of concurrent languages from a pragmatic point of view. On the other hand, problems modeled by using constraints can be solved faster and more efficiently using a concurrent system. Both directions are explored providing two separate lines of development. Firstly the expressive power of a concurrent language is studied, namely Constraint Handling Rules, that supports constraints as a primitive construct. The features of this language which make it Turing powerful are shown. Then a framework is proposed to solve constraint problems that is intended to be deployed on a concurrent system. For the development of this framework the concurrent language Jolie following the Service Oriented paradigm is used. Based on this experience, an extension to Service Oriented Languages is also proposed in ...

  9. Kinematical and EMG-classifications of a fencing attack.

    Science.gov (United States)

    Frère, J; Göpfert, B; Nüesch, C; Huber, C; Fischer, M; Wirz, D; Friederich, N F

    2011-01-01

    8 expert fencers were studied with a 3-dimensional motion analysis system. Each subject performed 10 flèche attacks toward a standardized target. Surface electromyography signals (EMG) were recorded of the deltoid pars clavicularis, infraspinatus and triceps brachii caput laterale muscles of the weapon arm. The recorded EMGs were averaged using EMG wavelet-transformation software. 4 phases were defined based on the arm kinematics and used to classify fencers into 2 groups. A first group of 4 fencers showed an early maximal elbow extension (Early MEE) whereas the second group presented a late maximal elbow extension (Late MEE). 2 EMG-classifications were based on this kinematical classification, one in the time-domain and the other in the frequency-domain by using the spherical classification. The time-domain EMG-classification showed a significantly ( P=0.03) higher normalized deltoid intensity for the Early MEE group (91 ± 18%) than the Late MEE group (36 ± 13%) in the attack phase. The spherical classification revealed that the activity of all the muscles was significantly classified (recognition rate 75%, P=0.04) between the 2 groups. This study of EMG and kinematics of the weapon upper limb in fencing proposes several classifications, which implies a relationship between kinematic strategies, muscular activations and fencing success.

  10. On Minimal Constraint Networks

    CERN Document Server

    Gottlob, Georg

    2011-01-01

    In a minimal binary constraint network, every tuple of a constraint relation can be extended to a solution. It was conjectured that computing a solution to such a network is NP complete. We prove this conjecture true and show that the problem remains NP hard even in case the total domain of all values that may appear in the constraint relations is bounded by a constant.

  11. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  12. Calibration of a Parallel Kinematic Machine Tool

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-mei; DING Hong-sheng; FU Tie; XIE Dian-huang; XU Jin-zhong; LI Hua-feng; LIU Hui-lin

    2006-01-01

    A calibration method is presented to enhance the static accuracy of a parallel kinematic machine tool by using a coordinate measuring machine and a laser tracker. According to the established calibration model and the calibration experiment, the factual 42 kinematic parameters of BKX-I parallel kinematic machine tool are obtained. By circular tests the comparison is made between the calibrated and the uncalibrated parameters and shows that there is 80% improvement in accuracy of this machine tool.

  13. Monitoring diver kinematics with dielectric elastomer sensors

    Science.gov (United States)

    Walker, Christopher R.; Anderson, Iain A.

    2017-04-01

    Diving, initially motivated for food purposes, is crucial to the oil and gas industry, search and rescue, and is even done recreationally by millions of people. There is a growing need however, to monitor the health and activity of divers. The Divers Alert Network has reported on average 90 fatalities per year since 1980. Furthermore an estimated 1000 divers require recompression treatment for dive-related injuries every year. One means of monitoring diver activity is to integrate strain sensors into a wetsuit. This would provide kinematic information on the diver potentially improving buoyancy control assessment, providing a platform for gesture communication, detecting panic attacks and monitoring diver fatigue. To explore diver kinematic monitoring we have coupled dielectric elastomer sensors to a wetsuit worn by the pilot of a human-powered wet submarine. This provided a unique platform to test the performance and accuracy of dielectric elastomer strain sensors in an underwater application. The aim of this study was to assess the ability of strain sensors to monitor the kinematics of a diver. This study was in collaboration with the University of Auckland's human-powered submarine team, Team Taniwha. The pilot, completely encapsulated in a hull, pedals to propel the submarine forward. Therefore this study focused on leg motion as that is the primary motion of the submarine pilot. Four carbon-filled silicone dielectric elastomer sensors were fabricated and coupled to the pilot's wetsuit. The first two sensors were attached over the knee joints, with the remaining two attached between the pelvis and thigh. The goal was to accurately measure leg joint angles thereby determining the position of each leg relative to the hip. A floating data acquisition unit monitored the sensors and transmitted data packets to a nearby computer for real-time processing. A GoPro Hero 4 silver edition was used to capture the experiments and provide a means of post-validation. The

  14. Kinematically complete chemical reaction dynamics

    Science.gov (United States)

    Trippel, S.; Stei, M.; Otto, R.; Hlavenka, P.; Mikosch, J.; Eichhorn, C.; Lourderaj, U.; Zhang, J. X.; Hase, W. L.; Weidemüller, M.; Wester, R.

    2009-11-01

    Kinematically complete studies of molecular reactions offer an unprecedented level of insight into the dynamics and the different mechanisms by which chemical reactions occur. We have developed a scheme to study ion-molecule reactions by velocity map imaging at very low collision energies. Results for the elementary nucleophilic substitution (SN2) reaction Cl- + CH3I → ClCH3 + I- are presented and compared to high-level direct dynamics trajectory calculations. Furthermore, an improved design of the crossed-beam imaging spectrometer with full three-dimensional measurement capabilities is discussed and characterization measurements using photoionization of NH3 and photodissociation of CH3I are presented.

  15. Kinematical Analysis of an Articulated Mechanism

    CERN Document Server

    Fleischfresser, Luciano

    2015-01-01

    The purpose of this work is twofold: to present mathematical expressions for the kinematics of an articulated mechanism and to perform numerical experiments with the implemented Fortran code. The system of rigid parts is made of two slender bars and a disk. A constant 2 rad/s counterclockwise rotation rate is imposed on the disk triggering the planar motion of the longer bar (link) and the rotation of the shorter one (output). Angular relations, velocities and accelerations are analyzed for a 90-degree turn of the disk. The inversion of the linking bar sense of rotation is well captured by the simulation, and the paper and pencil solutions that may lead to wrong conclusions are explained. Equations are derived from first principles and the Fortran code is placed under version control (currently, v.0.8-beta). This computer project is relevant for those in charge of vector dynamics courses and wishing to expose students to project-based learning activities.

  16. Investigating The Kinematics of Canids and Felids

    Science.gov (United States)

    Sur, D.

    2016-12-01

    For all organisms, metabolic energy is critical for survival. While moving efficiently is a necessity for large carnivores, the influence of kinematics on energy demand remains poorly understood. We measured the kinematics of dogs, wolves, and pumas to detect any differences in their respective energy expenditures. Using 22 kinematic parameters measured on 78 videos, we used one-way ANOVAs and paired T-tests to compare 5 experimental treatments among gaits in dogs (n=11 in 3 breed groups), wolves (n=2), and pumas (n=2). Across the measured parameters, we found greater kinematic similarity than expected among dog breeds and no trend in any of the 22 parameters regarding the effect of steepness on locomotion mechanics. Similarly, treadmill kinematics were nearly identical to those measured during outdoor movement. However, in 3 inches of snow, we observed significant differences (pwolves and dogs) to a felid (pumas), we found that pumas and dogs are the most kinematically distinct (differing in 13 of 22 parameters, compared with 5 of 22 for wolves and pumas). Lastly, compared with wolves, walking pumas had larger head angles (p=0.0025), forelimb excursion angles (p=0.0045), and hindlimb excursion angles (p=0.0327). After comparing the energetics of pumas and dogs with their respective kinematics, we noted that less dynamic kinematics result in energy savings. Through tracking the locations and gait behavior of large carnivores, novel sensor technology can reveal how indoor kinematics applies to wild animals and improve the conservation of these species.

  17. Finite rotation and nonlinear beam kinematics

    Science.gov (United States)

    Hodges, Dewey H.

    1987-01-01

    Standard means of representing finite rotation in rigid-body kinematics, including orientation angles, Euler parameters, and Rodrigues parameters, are reviewed and compared. General kinematical relations for a beam theory that treats arbitrarily large rotation are then presented. The standard methods of representing finite rotations are applied to these kinematical expressions, and comparison is made among the standard methods and additional methods found in the literature, such as quasi-coordinates and linear combinations of projection angles. The method of Rodrigues parameters is shown to stand out for both its simplicity and generality when applied to beam kinematics, a result that is really missing from the literature.

  18. Canonical quantum gravity in the Vassiliev invariants arena; 1, Kinematical structure

    CERN Document Server

    Di Bartolo, C; Griego, J R; Pullin, J; Bartolo, Cayetano Di; Gambini, Rodolfo; Griego, Jorge; Pullin, Jorge

    2000-01-01

    We generalize the idea of Vassiliev invariants to the spin network context, with the aim of using these invariants as a kinematical arena for a canonical quantization of gravity. This paper presents a detailed construction of these invariants (both ambient and regular isotopic) requiring a significant elaboration based on the use of Chern-Simons perturbation theory which extends the work of Kauffman, Martin and Witten to four-valent networks. We show that this space of knot invariants has the crucial property -from the point of view of the quantization of gravity- of being loop differentiable in the sense of distributions. This allows the definition of diffeomorphism and Hamiltonian constraints. We show that the invariants are annihilated by the diffeomorphism constraint. In a companion paper we elaborate on the definition of a Hamiltonian constraint, discuss the constraint algebra, and show that the construction leads to a consistent theory of canonical quantum gravity.

  19. Multibody motion in implicitly constrained director format with links via explicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2013-01-01

    A conservative time integration algorithm is developed for constrained mechanical systems of kinematically linked rigid bodies based on convected base vectors. The base vectors are represented in terms of their absolute coordinates, hence the formulation makes use of three translation components......, plus nine base vector components for each rigid body. Both internal and external constraints are considered. Internal constraints are used to enforce orthonormality of the three base vectors by constraining the equivalent Green strain components, while the external constraints are associated...... with the presence of kinematic joints for linking bodies together. The equations of motion are derived from Hamilton’s equations with an augmented Hamiltonian in which internal and external constraints initially are included via Lagrange multipliers. Subsequently the Lagrange multipliers associated with internal...

  20. Active kinematics of the southern Red Sea

    Science.gov (United States)

    McClusky, S.; Reilinger, R.; Ogubazghi, G.; Amlesom, A.; Haileab, B.; Sholan, J.; Vernant, P.; Arrajehi, A.

    2009-04-01

    GPS measurements adjacent to the southern Red Sea and around the Afar Triple Junction (Red Sea Rift-Gulf of Aden Rift-East African Rift), indicate that the Red Sea rift bifurcates south of 16° N latitude with one branch following a continuation of the main Red Sea rift (~150° Azimuth) and the other oriented roughly N-S traversing the Danakil Depression/Afar volcanic province. These two rift branches account for the full Arabia-Nubia relative motion. Within the resolution of our observations, the partitioning of extension between rift branches varies linearly along strike; north of ~16°N extension (~15 mm/yr at 16°N) is confined to the main Red Sea rift while at the latitude of the Afar Triple Junction (~12°N) extension (~20 mm/yr) has transferred completely to the Danakil-Afar Depression. The Danakil block separates the two rifts and rotates counterclockwise, accommodating extension along the rifts and developing the triangular geometry of the Danakil/Afar Depression. Extrapolating the geodetic rates to the time of initial rifting of Arabia from Nubia (~25 ± 3 Ma) and estimating total extension across the rift branches from the present-day widths of the rifts suggests that Arabia-Nubia relative motion has been roughly constant since the initiation of Red Sea spreading, and that extension was initially confined to the main Red Sea rift with the presently observed bifurcation initiating at about 17 Ma.

  1. Kinematic analysis of rope skipper's stability

    Science.gov (United States)

    Ab Ghani, Nor Atikah; Rambely, Azmin Sham

    2014-06-01

    There are various kinds of jumping that can be done while performing rope skipping activity. This activity was always associated with injury. But, if the rope skipper can perform the activity in a right way, it is believed that the injury might be reduced. The main purpose of this paper is to observe the stability of rope skipper from a biomechanics perspective, which are the centre of mass, angle at the ankle, knee and hip joints and also the trajectory for the ipsilateral leg between the two types of skip which is one leg and two legs. Six healthy, physically active subject, two males and four females (age: 8.00±1.25 years, weight: 17.90±6.85 kg and height: 1.22±0.08 m) participated in this study. Kinematic data of repeated five cycles of rope skipping activity was captured by using Vicon Nexus system. Based on the data collected, skipping with two legs shows more stable behavior during preparation, flight and landing phases. It is concluded that landing on the balls of the feet, lowering the trajectory positions of the feet from the ground as well as flexion of each joint which would reduce the injury while landing.

  2. Kinematics of the South Atlantic rift

    Directory of Open Access Journals (Sweden)

    C. Heine

    2013-01-01

    Full Text Available The South Atlantic rift basin evolved as branch of a large Jurassic-Cretaceous intraplate rift zone between the African and South American plates during the final breakup of western Gondwana. While the relative motions between South America and Africa for post-breakup times are well resolved, many issues pertaining to the fit reconstruction and particular the relation between kinematics and lithosphere dynamics during pre-breakup remain unclear in currently published plate models. We have compiled and assimilated data from these intraplated rifts and constructed a revised plate kinematic model for the pre-breakup evolution of the South Atlantic. Based on structural restoration of the conjugate South Atlantic margins and intracontinental rift basins in Africa and South America, we achieve a tight fit reconstruction which eliminates the need for previously inferred large intracontinental shear zones, in particular in Patagonian South America. By quantitatively accounting for crustal deformation in the Central and West African rift zone, we have been able to indirectly construct the kinematic history of the pre-breakup evolution of the conjugate West African-Brazilian margins. Our model suggests a causal link between changes in extension direction and velocity during continental extension and the generation of marginal structures such as the enigmatic Pre-salt sag basin and the São Paulo High. We model an initial E–W directed extension between South America and Africa (fixed in present-day position at very low extensional velocities until Upper Hauterivian times (≈126 Ma when rift activity along in the equatorial Atlantic domain started to increase significantly. During this initial ≈17 Myr-long stretching episode the Pre-salt basin width on the conjugate Brazilian and West African margins is generated. An intermediate stage between 126.57 Ma and Base Aptian is characterised by strain localisation, rapid lithospheric weakening in the

  3. Proximal arm kinematics affect grip force-load force coordination.

    Science.gov (United States)

    Vermillion, Billy C; Lum, Peter S; Lee, Sang Wook

    2015-10-01

    During object manipulation, grip force is coordinated with load force, which is primarily determined by object kinematics. Proximal arm kinematics may affect grip force control, as proximal segment motion could affect control of distal hand muscles via biomechanical and/or neural pathways. The aim of this study was to investigate the impact of proximal kinematics on grip force modulation during object manipulation. Fifteen subjects performed three vertical lifting tasks that involved distinct proximal kinematics (elbow/shoulder), but resulted in similar end-point (hand) trajectories. While temporal coordination of grip and load forces remained similar across the tasks, proximal kinematics significantly affected the grip force-to-load force ratio (P = 0.042), intrinsic finger muscle activation (P = 0.045), and flexor-extensor ratio (P muscles and the elbow joint cannot fully explain the observed changes, as task-related changes in intrinsic hand muscle activation were greater than in extrinsic hand muscles. Rather, between-task variation in grip force (highest during task 3) appears to contrast to that in shoulder joint velocity/acceleration (lowest during task 3). These results suggest that complex neural coupling between the distal and proximal upper extremity musculature may affect grip force control during movements, also indicated by task-related changes in intermuscular coherence of muscle pairs, including intrinsic finger muscles. Furthermore, examination of the fingertip force showed that the human motor system may attempt to reduce variability in task-relevant motor output (grip force-to-load force ratio), while allowing larger fluctuations in output less relevant to task goal (shear force-to-grip force ratio).

  4. Activity prediction of substrates in NADH-dependent carbonyl reductase by docking requires catalytic constraints and charge parameterization of catalytic zinc environment.

    Science.gov (United States)

    Dhoke, Gaurao V; Loderer, Christoph; Davari, Mehdi D; Ansorge-Schumacher, Marion; Schwaneberg, Ulrich; Bocola, Marco

    2015-11-01

    Molecular docking of substrates is more challenging compared to inhibitors as the reaction mechanism has to be considered. This becomes more pronounced for zinc-dependent enzymes since the coordination state of the catalytic zinc ion is of greater importance. In order to develop a predictive substrate docking protocol, we have performed molecular docking studies of diketone substrates using the catalytic state of carbonyl reductase 2 from Candida parapsilosis (CPCR2). Different docking protocols using two docking methods (AutoDock Vina and AutoDock4.2) with two different sets of atomic charges (AM1-BCC and HF-RESP) for catalytic zinc environment and substrates as well as two sets of vdW parameters for zinc ion were examined. We have selected the catalytic binding pose of each substrate by applying mechanism based distance criteria. To compare the performance of the docking protocols, the correlation plots for the binding energies of these catalytic poses were obtained against experimental Vmax values of the 11 diketone substrates for CPCR2. The best correlation of 0.73 was achieved with AutoDock4.2 while treating catalytic zinc ion in optimized non-bonded (NBopt) state with +1.01 charge on the zinc ion, compared to 0.36 in non-bonded (+2.00 charge on the zinc ion) state. These results indicate the importance of catalytic constraints and charge parameterization of catalytic zinc environment for the prediction of substrate activity in zinc-dependent enzymes by molecular docking. The developed predictive docking protocol described here is in principle generally applicable for the efficient in silico substrate spectra characterization of zinc-dependent ADH.

  5. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  6. Credit Constraints in Education

    Science.gov (United States)

    Lochner, Lance; Monge-Naranjo, Alexander

    2012-01-01

    We review studies of the impact of credit constraints on the accumulation of human capital. Evidence suggests that credit constraints have recently become important for schooling and other aspects of households' behavior. We highlight the importance of early childhood investments, as their response largely determines the impact of credit…

  7. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  8. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  9. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  10. Decentralized Constraint Satisfaction

    CERN Document Server

    Duffy, K R; Leith, D J

    2011-01-01

    Constraint satisfaction problems (CSPs) lie at the heart of many modern industrial and commercial tasks. An important new collection of CSPs has recently been emerging that differ from classical problems in that they impose constraints on the class of algorithms that can be used to solve them. In computer network applications, these constraints arise as the variables within the CSP are located at physically distinct devices that cannot communicate. At each instant, every variable only knows if all its constraints are met or at least one is not. Consequently, the CSP's solution must be found using a decentralized approach. Existing algorithms for solving CSPs are either centralized or distributed, both of which violate these algorithmic constraints. In this article we present the first algorithm for solving CSPs that fulfills these new requirements. It is fully decentralized, making no use of a centralized controller or message-passing between variables. We prove that this algorithm converges with probability ...

  11. Constraints in Quantum Geometrodynamics

    CERN Document Server

    Gentle, A P; Kheyfets, A I; Miller, W A; Gentle, Adrian P.; George, Nathan D.; Kheyfets, Arkady; Miller, Warner A.

    2003-01-01

    We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3-geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamic equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approach lead to the well known problems of the description of time evolution. These problems of time are both of interpretational and technical nature. In contrast, the so-called geometrodynamic quantization procedure on the superspace of the true dynamic variables separates the issue of quantization from enforcing the constraints. The resulting theory takes into account the states that are off shell with respect to the constraints, and thus avoids the problems of time. Here, we develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context ...

  12. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Directory of Open Access Journals (Sweden)

    Vincent Richard

    Full Text Available The use of multi-body optimisation (MBO to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm. The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  13. Knee Kinematics Estimation Using Multi-Body Optimisation Embedding a Knee Joint Stiffness Matrix: A Feasibility Study.

    Science.gov (United States)

    Richard, Vincent; Lamberto, Giuliano; Lu, Tung-Wu; Cappozzo, Aurelio; Dumas, Raphaël

    2016-01-01

    The use of multi-body optimisation (MBO) to estimate joint kinematics from stereophotogrammetric data while compensating for soft tissue artefact is still open to debate. Presently used joint models embedded in MBO, such as mechanical linkages, constitute a considerable simplification of joint function, preventing a detailed understanding of it. The present study proposes a knee joint model where femur and tibia are represented as rigid bodies connected through an elastic element the behaviour of which is described by a single stiffness matrix. The deformation energy, computed from the stiffness matrix and joint angles and displacements, is minimised within the MBO. Implemented as a "soft" constraint using a penalty-based method, this elastic joint description challenges the strictness of "hard" constraints. In this study, estimates of knee kinematics obtained using MBO embedding four different knee joint models (i.e., no constraints, spherical joint, parallel mechanism, and elastic joint) were compared against reference kinematics measured using bi-planar fluoroscopy on two healthy subjects ascending stairs. Bland-Altman analysis and sensitivity analysis investigating the influence of variations in the stiffness matrix terms on the estimated kinematics substantiate the conclusions. The difference between the reference knee joint angles and displacements and the corresponding estimates obtained using MBO embedding the stiffness matrix showed an average bias and standard deviation for kinematics of 0.9±3.2° and 1.6±2.3 mm. These values were lower than when no joint constraints (1.1±3.8°, 2.4±4.1 mm) or a parallel mechanism (7.7±3.6°, 1.6±1.7 mm) were used and were comparable to the values obtained with a spherical joint (1.0±3.2°, 1.3±1.9 mm). The study demonstrated the feasibility of substituting an elastic joint for more classic joint constraints in MBO.

  14. Probing RNA Native Conformational Ensembles with Structural Constraints.

    Science.gov (United States)

    Fonseca, Rasmus; van den Bedem, Henry; Bernauer, Julie

    2016-05-01

    Noncoding ribonucleic acids (RNA) play a critical role in a wide variety of cellular processes, ranging from regulating gene expression to post-translational modification and protein synthesis. Their activity is modulated by highly dynamic exchanges between three-dimensional conformational substates, which are difficult to characterize experimentally and computationally. Here, we present an innovative, entirely kinematic computational procedure to efficiently explore the native ensemble of RNA molecules. Our procedure projects degrees of freedom onto a subspace of conformation space defined by distance constraints in the tertiary structure. The dimensionality reduction enables efficient exploration of conformational space. We show that the conformational distributions obtained with our method broadly sample the conformational landscape observed in NMR experiments. Compared to normal mode analysis-based exploration, our procedure diffuses faster through the experimental ensemble while also accessing conformational substates to greater precision. Our results suggest that conformational sampling with a highly reduced but fully atomistic representation of noncoding RNA expresses key features of their dynamic nature.

  15. Kinematics of planet-host stars and their relation with dynamical streams in the solar neighbourhood

    CERN Document Server

    Ecuvillon, A; Pont, F; Santos, N C; Mayor, M

    2006-01-01

    We present a detailed study on the kinematics of metal-rich stars with and without planets, and their relation with the Hyades, Sirius and Hercules dynamical streams in the solar neighbourhood. Accurate kinematics have been derived for all the stars belonging to the CORALIE planet search survey. We used precise radial velocity measurements and CCF parameters from the CORALIE database, and parallaxes, photometry and proper motions from the HIPPARCOS and Tycho-2 catalogues. The location of stars with planets in the thin or thick discs has been analysed using both kinematic and chemical constraints. We compare the kinematic behaviour of known planet-host stars to the remaining targets belonging to the volume-limited sample, in particular to its metal-rich population. The high average metallicity of the Hyades stream is confirmed. The planet-host targets show a kinematic behaviour similar to that of the metal-rich comparison subsample, rather than to that of the comparison sample as a whole, thus supporting a pri...

  16. The kinematics modeling based on Spinor theory for CT-guided hybrid robot

    Institute of Scientific and Technical Information of China (English)

    Tang Can; Liu Da; Wang Tianmiao; Yun Chao

    2009-01-01

    This paper focused on a simplified method for solving the hybrid robot kinematics in CT-guided (computerized tomography, CT) surgery. By position constraint introduced, the hybrid robot can be transformed as a redundant serial 7-DOF robot. The forward displacement calculation was developed based on the product-of-exponential formula (POE). Because of the kinematics complexity of the hybrid and redundant robot, the combination technique of Ulrich two-step iteration method and paul variables detachment method (UTI-PVD) was introduced to fulfill the inverse kinematics of redundant robot, the novelty of which lay in the flexibility of various robots structures and in high calculation efficiency for real-time control. The process of solving the inverse displacement was analyzed. The UTI-PVD method can be applicable to kinematics of many robots, especially for redundant robots with more than 6DOF. The kinematics simulation was provided, and robot dexterity analysis was presented. The results indicated that the hybrid robot could implement the minimally invasive CT-guided surgery.

  17. Kinematics of the free throw in basketball

    Science.gov (United States)

    Tan, A.; Miller, G.

    1981-06-01

    The kinematics of the two basic styles of free throw in basketball are discussed. It is shown that from a purely kinematic and trajectory point of view, the overhand push shot is preferable to the underhand loop shot. The advantages of the underhand shot lie in the actual execution of the shot.

  18. Automated kinematic generator for surgical robotic systems.

    Science.gov (United States)

    Jung, David L; Dixon, Warren E; Pin, François G

    2004-01-01

    Unlike traditional assembly line robotic systems that have a fixed kinematic structure associated with a single tool for a structured task, next-generation robotic surgical assist systems will be required to use an array of end-effector tools. Once a robot is connected with a tool, the kinematic equations of motion are altered. Given the need to accommodate evolving surgical challenges and to alleviate the restrictions imposed by the confined minimally invasive environment, new surgical tools may resemble small flexible snakes rather than rigid, cable driven instruments. Connecting to these developing articulated tools will significantly alter the overall kinematic structure of a robotic system. In this paper we present a technique for real-time automated generation and evaluation of manipulator kinematic equations that exhibits the combined advantages of existing methods-speed and flexibility to kinematic change--without their disadvantages.

  19. Off-shell Color-Kinematics Duality

    CERN Document Server

    Mastrolia, Pierpaolo; Schubert, Ulrich; Bobadilla, William J Torres

    2015-01-01

    We elaborate on the color-kinematics duality for off-shell diagrams in gauge theories coupled to matter, by investigating the scattering process $gg\\to ss, q\\bar q, gg$, and show that the Jacobi relations for the kinematic numerators of off-shell diagrams, built with Feynman rules in axial gauge, reduces to a color-kinematics violating term due to the contributions of sub-graphs only. Such anomaly vanishes when the four particles connected by the Jacobi relation are on their mass shell with vanishing squared momenta, being either external or cut particles, where the validity of the color-kinematics duality is recovered. We discuss the role of this off-shell decomposition in the direct construction of higher-multiplicity numerators satisfying color-kinematics identity, providing an explicit example for the QCD process $gg\\to q\\bar{q}g$.

  20. Functional constraints on SoxE proteins in neural crest development: The importance of differential expression for evolution of protein activity.

    Science.gov (United States)

    Lee, Eric M; Yuan, Tian; Ballim, Reyna D; Nguyen, Kristy; Kelsh, Robert N; Medeiros, Daniel M; McCauley, David W

    2016-10-01

    Vertebrate SoxE genes (Sox8, 9, and 10) are key regulators of neural crest cell (NCC) development. These genes arose by duplication from a single SoxE gene in the vertebrate ancestor. Although SoxE paralogs are coexpressed early in NCC development, later, Sox9 is restricted to skeletogenic lineages in the head, and Sox10 to non-skeletogenic NCC in the trunk and head. When this subfunctionalization evolved and its possible role in the evolution of the neural crest are unknown. Sea lampreys are basal vertebrates that also possess three SoxE genes, while only a single SoxE is present in the cephalochordate amphioxus. In order to address the functional divergence of SoxE genes, and to determine if differences in their biochemical functions may be linked to changes in neural crest developmental potential, we examined the ability of lamprey and amphioxus SoxE genes to regulate differentiation of NCC derivatives in zebrafish colourless (cls) mutants lacking expression of sox10. Our findings suggest that the proto-vertebrate SoxE gene possessed both melanogenic and neurogenic capabilities prior to SoxE gene duplication. Following the agnathan-gnathostome split, lamprey SoxE1 and SoxE3 largely lost their melanogenic and/or enteric neurogenic properties, while gnathostome SoxE paralogs have retained functional conservation. We posit that this difference in protein subfunctionalization is a direct consequence of the independent regulation of SoxE paralog expression between the two lineages. Specifically, we propose that the overlapping expression of gnathostome SoxE paralogs in early neural crest largely constrained the function of gnathostome SoxE proteins. In contrast, the largely non-overlapping expression of lamprey SoxE paralogs allowed them to specialize with regard to their DNA-binding and/or protein interaction properties. Restriction of developmental potential among cranial and trunk neural crest in lampreys may be related to constraints on SoxE activity among

  1. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  2. Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051 (China); Lu, Tung-Wu [Institute of Biomedical Engineering, National Taiwan University, Taiwan 10051, Republic of China and Department of Orthopaedic Surgery, School of Medicine, National Taiwan University, Taiwan 10617 (China); Shih, Ting-Fang [Department of Medical Imaging, National Taiwan University, Taiwan 10051 (China); Wang, Ting-Ming [Department of Orthopaedic Surgery, National Taiwan University Hospital, Taiwan 10051 (China)

    2013-03-15

    Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopy images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than -0.5 (0.6) and -0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was

  3. Communication with Disturbance Constraints

    CERN Document Server

    Bandemer, Bernd

    2011-01-01

    The problem of communication with disturbance constraints is introduced. The rate-disturbance region is established for the single constraint case. The optimal encoding scheme turns out to be the same as the Han-Kobayashi scheme for the two user-pair interference channel. For communication with two disturbance constraints, a coding scheme and a corresponding inner bound for the deterministic case are presented. The results suggest a natural way to obtain a new inner bound on the capacity region of the interference channel with more than two user pairs.

  4. Effects of modified constraint-induced movement therapy and functional bimanual training on upper extremity function and daily activities in a patient with incomplete spinal cord injury: a case study.

    Science.gov (United States)

    Kim, Yeon-Ju; Kim, Jin-Kyung; Park, So-Yeon

    2015-12-01

    [Purpose] In this study, we examined effects of modified constraint-induced movement therapy (m-CIMT) and functional bimanual training, when applied to a patient with incomplete spinal cord injury, on upper extremity function and daily activities. [Subject and Methods] One patient, diagnosed with C4 incomplete spinal cord injury, underwent physical therapy with constraint-induced movement therapy for 3 hours and task-oriented bimanual training for 1 hour, per day. This combined 4-hour session was performed five times a week, for 3 weeks, totaling 15 sessions. Upper extremity function was measured using the Manual Function Test (MFT) and Box & Block Test (BBT). Additionally, Spinal Cord Independence Measure Version III (SCIM-III) and Short Form 36 Health Survey (SF-36) were used to assess functional outcomes. [Results] Mobility of the hand and overall function of upper extremities were enhanced following intervention. Moreover, the subject's quality of life and ability to carry out daily activities also improved. [Conclusion] Modified constraint-induced movement therapy and bimanual training was effective in enhancing upper extremity function and performance of daily routines in a patient with incomplete spinal cord injury. Further studies, recruiting multiple subjects, should focus on m-CIMT using diverse methods, performed during the course of daily activities.

  5. Torque exerted on the side of crustal blocks controls the kinematics of Ethiopian Rift

    Science.gov (United States)

    Muluneh, Ameha A.; Kidane, Tesfaye; Cuffaro, Marco; Doglioni, Carlo

    2016-04-01

    Plate tectonic stress at active plate boundary can arises from 1) a torque applied on the side of lithospheric blocks and 2) a torque at the base of the lithosphere due to the flow of the underlying mantle. In this paper we use a simple force balance analysis to compare side and basal shear stresses and their contribution in driving kinematics and deformation in the Ethiopian Rift (ER), in the northern part of the East African Rift System (EARS). Assuming the constraints of the ER given by the dimension of the lithospheric blocks, the strain rate, the viscosity of the low velocity zone (LVZ) and the depth of the brittle-ductile transition zone, the lateral torque is several orders of magnitude higher than the basal torque. The minor contribution of basal torque might be due to low viscosity in the LVZ. Both Africa and Somalia plates are moving to the "west" relative to the mantle and there are not slabs that can justify this pull and consequent motion. Therefore, we invoke that westerly oriented tidal torque on Africa and Somalia plates in providing the necessary side torque in the region. This plate motion predicts significant sinistral transtension along the ER and rift parallel strike-slip faulting similar to the estimated angular velocity vector for tectonic blocks and GPS observations. Vertical axis block rotations are observed in areas where the lithospheric mantle is removed and strain is widely distributed.

  6. Optimization under Nonlinear Constraints

    OpenAIRE

    1982-01-01

    In this paper a timesaving method is proposed for maximizing likelihood functions when the parameter space is subject to nonlinear constraints, expressible as second order polynomials. The suggested approach is especially attractive when dealing with systems with many parameters.

  7. Postural Hand Synergies during Environmental Constraint Exploitation

    Directory of Open Access Journals (Sweden)

    Cosimo Della Santina

    2017-08-01

    Full Text Available Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms of a synergistic behavior in the generation of hand postures, i.e., using a reduced set of commonly used kinematic patterns. This is in analogy with previous studies showing the presence of such behavior in different tasks, such as grasping. We investigated this hypothesis in experiments performed by six subjects, who were asked to grasp objects from a flat surface. We quantitatively characterized hand posture behavior from a kinematic perspective, i.e., the hand joint angles, in both pre-shaping and during the interaction with the environment. To determine the role of tactile feedback, we repeated the same experiments but with subjects wearing a rigid shell on the fingertips to reduce cutaneous afferent inputs. Results show the persistence of at least two postural synergies in all the considered experimental conditions and phases. Tactile impairment does not alter significantly the first two synergies, and contact with the environment generates a change only for higher order Principal Components. A good match also arises between the first synergy found in our analysis and the first synergy of grasping as quantified by previous work. The present study is motivated by the interest of learning from the human example, extracting lessons that can be applied in robot design and control. Thus, we conclude with a discussion on implications for robotics of our findings.

  8. Astrophysical Constraints on Planck Scale Dissipative Phenomena

    Science.gov (United States)

    Liberati, Stefano; Maccione, Luca

    2014-04-01

    The emergence of a classical spacetime from any quantum gravity model is still a subtle and only partially understood issue. If indeed spacetime is arising as some sort of large scale condensate of more fundamental objects, then it is natural to expect that matter, being a collective excitation of the spacetime constituents, will present modified kinematics at sufficiently high energies. We consider here the phenomenology of the dissipative effects necessarily arising in such a picture. Adopting dissipative hydrodynamics as a general framework for the description of the energy exchange between collective excitations and the spacetime fundamental degrees of freedom, we discuss how rates of energy loss for elementary particles can be derived from dispersion relations and used to provide strong constraints on the base of current astrophysical observations of high-energy particles.

  9. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Ikhsan Eka Prasetia

    2015-03-01

    Full Text Available In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desired position by Denso robot manipulator. Forward kinematics produce the desired position by the end-effector. Inverse kinematics produce joint angle, where the inverse kinematics produce eight conditions obtained from closed form solution with geometry approach to reach the desired position by the end-effector.

  10. Constraint-Referenced Analytics of Algebra Learning

    Science.gov (United States)

    Sutherland, Scot M.; White, Tobin F.

    2016-01-01

    The development of the constraint-referenced analytics tool for monitoring algebra learning activities presented here came from the desire to firstly, take a more quantitative look at student responses in collaborative algebra activities, and secondly, to situate those activities in a more traditional introductory algebra setting focusing on…

  11. Anisotropic superconductivity driven by kinematic interaction

    Science.gov (United States)

    Ivanov, V. A.

    2000-11-01

    We have analysed the effect of kinematic pairing on the symmetry of superconducting order parameter for a square lattice in the frame of the strongly correlated Hubbard model. It is argued that in the first perturbation order the kinematic interaction renormalizes the Hubbard-I dispersions and provides at low doping the mixed singlet (s + s*)-wave superconductivity, giving way at higher doping to the triplet p-wave superconductivity. The obtained phase diagram depends only on the hopping integral parameter. The influence of the Coulomb repulsion on the kinematic superconducting pairing has been estimated. The (s + s*)-wave gap and the thermodynamic critical magnetic field have been derived.

  12. Implementation of Complex Projects Using Constraint Programming

    Directory of Open Access Journals (Sweden)

    Miodrag Strak

    2012-09-01

    Full Text Available During the implementation of the complex projects, all planned activities and resources must be taken into account. In general, it is necessary to assign the resources to the activities, but to also avoid simultaneous engagement of resources for multiple activities. In order to solve these problems, various techniques and methods are used. Mathematic and integer programming, genetic algorithms, simulated annealing, or taboo search are just some of the techniques used for solving this problem. Constraint programming comes from artificial intelligence i.e. papers from this area that occurred in 1960s and 1970s. Constraints exist in every segment of human environment. They represent a natural medium for expressing relations that exist in the physical world. Fulfilment of constraints is used in many different areas. Problems such as scheduling, allocations etc. are typical examples of constraints problems, where the basic concept of constraint programming can be applied. This paper considered implementation of the Bor Regional Development Project. Development of constraint programming was followed by the development of appropriate tools. B-Prolog was used in this paper. Many systems, including B-Prolog, enable interface with classic object-oriented languages, such as C++ or Java. One of the greatest advantages is the possibility of simple modelling, even for beginners in planning and implementation of the project.

  13. Kinematics of the Hercules Supercluster

    CERN Document Server

    Barmby, P; Barmby, Pauline; Huchra, John P.

    1997-01-01

    The Hercules Supercluster consists of the Abell clusters 2147, 2151, and 2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well-separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. 414 galaxies are in the supercluster, about three times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the KMM mixture-modeling algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821(+68)(-55) and 715(+81)(-61) km/s. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kin...

  14. Edge-driven microplate kinematics

    Science.gov (United States)

    Schouten, Hans; Klitgord, Kim D.; Gallo, David G.

    1993-01-01

    It is known from plate tectonic reconstructions that oceanic microplates undergo rapid rotation about a vertical axis and that the instantaneous rotation axes describing the microplate's motion relative to the bounding major plates are frequently located close to its margins with those plates, close to the tips of propagating rifts. We propose a class of edge-driven block models to illustrate how slip across the microplate margins, block rotation, and propagation of rifting may be related to the relative motion of the plates on either side. An important feature of these edge-driven models is that the instantaneous rotation axes are always located on the margins between block and two bounding plates. According to those models the pseudofaults or traces of disrupted seafloor resulting from the propagation of rifting between microplate and major plates may be used independently to approximately trace the continuous kinematic evolution of the microplate back in time. Pseudofault geometries and matching rotations of the Easter microplate show that for most of its 5 m.y. history, block rotation could be driven by the drag of the Nazca and Pacific plates on the microplate's edges rather than by a shear flow of mantle underneath.

  15. Optimal Occupant Kinematics and Crash Pulse for Automobile Frontal Impact

    Directory of Open Access Journals (Sweden)

    Zhiqing Cheng

    2009-01-01

    Full Text Available Based on a lumped-parameter model of the occupant-vehicle system, optimal kinematics of the occupant in frontal impact are investigated. It is found that for the minimization of the peak occupant deceleration, the optimal kinematics move the occupant at a constant deceleration. Based on this the optimal vehicle crash pulse is investigated. The optimal crash pulse for passive restraint systems is found to be: a positive impulse at the onset, an immediate plunge followed by a gradual rebound, and finally a positive level period. The relation of the peak occupant deceleration to the impact speed, crash deformation, and vehicle interior rattlespace is established. The optimal crash pulse for active and pre-acting restraint systems is discussed.

  16. VRACK: measuring pedal kinematics during stationary bike cycling.

    Science.gov (United States)

    Farjadian, Amir B; Kong, Qingchao; Gade, Venkata K; Deutsch, Judith E; Mavroidis, Constantinos

    2013-06-01

    Ankle impairment and lower limb asymmetries in strength and coordination are common symptoms for individuals with selected musculoskeletal and neurological impairments. The virtual reality augmented cycling kit (VRACK) was designed as a compact mechatronics system for lower limb and mobility rehabilitation. The system measures interaction forces and cardiac activity during cycling in a virtual environment. The kinematics measurement was added to the system. Due to the constrained problem definition, the combination of inertial measurement unit (IMU) and Kalman filtering was recruited to compute the optimal pedal angular displacement during dynamic cycling exercise. Using a novel benchmarking method the accuracy of IMU-based kinematics measurement was evaluated. Relatively accurate angular measurements were achieved. The enhanced VRACK system can serve as a rehabilitation device to monitor biomechanical and physiological variables during cycling on a stationary bike.

  17. Kinematic, kinetic and EMG patterns during downward squatting.

    Science.gov (United States)

    Dionisio, Valdeci Carlos; Almeida, Gil Lúcio; Duarte, Marcos; Hirata, Rogério Pessoto

    2008-02-01

    The aim of this study was to investigate the kinematic, kinetic, and electromyographic pattern before, during and after downward squatting when the trunk movement is restricted in the sagittal plane. Eight healthy subjects performed downward squatting at two different positions, semisquatting (40 degrees knee flexion) and half squatting (70 degrees knee flexion). Electromyographic responses of the vastus medialis oblique, vastus medialis longus, rectus femoris, vastus lateralis, biceps femoris, semitendineous, gastrocnemius lateralis, and tibialis anterior were recorded. The kinematics of the major joints were reconstructed using an optoelectronic system. The center of pressure (COP) was obtained using data collected from one force plate, and the ankle and knee joint torques were calculated using inverse dynamics. In the upright position there were small changes in the COP and in the knee and ankle joint torques. The tibialis anterior provoked the disruption of this upright position initiating the squat. During the acceleration phase of the squat the COP moved posteriorly, the knee joint torque remained in flexion and there was no measurable muscle activation. As the body went into the deceleration phase, the knee joint torque increased towards extension with major muscle activities being observed in the four heads of the quadriceps. Understanding these kinematic, kinetic and EMG strategies before, during and after the squat is expected to be beneficial to practitioners for utilizing squatting as a task for improving motor function.

  18. Impact of uncertain reference-frame motions in plate kinematic reconstructions: A theoretical appraisal

    Science.gov (United States)

    Iaffaldano, Giampiero; Stein, Seth

    2017-01-01

    Geoscientists infer past plate motions, which serve as fundamental constraints for a range of studies, from observations of magnetic isochrons as well as hotspots tracks on the ocean floor and, for stages older than the Cretaceous, from paleomagnetic data. These observations effectively represent time-integrals of past plate motions but, because they are made at present, yield plate kinematics naturally tied to a present-day reference-frame, which may be another plate or a hotspots system. These kinematics are therefore different than those occurred at the time when the rocks acquired their magnetisation or when hotspot-related marine volcanism took place, and are normally corrected for the reference-frame absolute motion (RFAM) that occurred since then. The impact of true-polar-wander events on paleomagnetic data and the challenge of inferring hotspot drifts result in RFAMs being less resolved - in a temporal sense - and prone to noise. This limitation is commonly perceived to hamper the correction of plate kinematic reconstructions for RFAMs, but the extent to which this may be the case has not been explored. Here we assess the impact of uncertain RFAMs on kinematic reconstructions using synthetic models of plate motions over 100 million years. We use randomly-drawn models for the kinematics of two plates separated by a spreading ridge to generate a synthetic magnetisation pattern of the ocean floor. The kinematics we infer from such a pattern are outputs that we correct for synthetic RFAMs using two equivalent methods (a classical one as well as another that we propose and test here) and then compare to the 'true' motions input. We assess the misfits between true and inferred kinematics by exploring a statistically-significant number of models where we systematically downgrade the temporal resolution of RFAM synthetic data and add noise to them. We show that even poorly-resolved, noisy RFAMs are sufficient to retrieve reliable plate kinematic reconstructions

  19. Kinematic analysis of movement imitation in apraxia

    National Research Council Canada - National Science Library

    Hermsdörfer, J; Mai, N; Spatt, J; Marquardt, C; Veltkamp, R; Goldenberg, G

    1996-01-01

    Accuracy of the final position and kinematics of movement were analysed during the imitation of meaningless gestures in patients with unilateral brain lesions who performed with the hand ipsilateral...

  20. Estimating total knee replacement joint load ratios from kinematics.

    Science.gov (United States)

    Fitzpatrick, Clare K; Rullkoetter, Paul J

    2014-09-22

    Accurate prediction of loads acting at the joint in total knee replacement (TKR) patients is key to developing experimental or computational simulations which evaluate implant designs under physiological loading conditions. In vivo joint loads have been measured for a small number of telemetric TKR patients, but in order to assess device performance across the entire patient population, a larger patient cohort is necessary. This study investigates the accuracy of predicting joint loads from joint kinematics. Specifically, the objective of the study was to assess the accuracy of internal-external (I-E) and anterior-posterior (A-P) joint load predictions from I-E and A-P motions under a given compressive load, and to evaluate the repeatability of joint load ratios (I-E torque to compressive force (I-E:C), and A-P force to compressive force (A-P:C)) for a range of compressive loading profiles. A tibiofemoral finite element model was developed and used to simulate deep knee bend, chair-rise and step-up activities for five patients. Root-mean-square (RMS) differences in I-E:C and A-P:C load ratios between telemetric measurements and model predictions were less than 1.10e-3 Nm/N and 0.035 N/N for all activities. I-E:C and A-P:C load ratios were consistently reproduced regardless of the compressive force profile applied (RMS differences less than 0.53e-3 Nm/N and 0.010 N/N, respectively). When error in kinematic measurement was introduced to the model, joint load predictions were forgiving to kinematic measurement error when conformity between femoral and tibial components was low. The prevalence of kinematic data, in conjunction with the analysis presented here, facilitates determining the scope of A-P and I-E joint loading ratios experienced by the TKR population.

  1. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Haibo; Guo, Sheng [Beijing Jiaotong University, Beijing (China)

    2017-04-15

    In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations.

  2. Morphologic and Kinematic Characteristics of Elite Sprinters

    OpenAIRE

    Čoh, M.; Milanović, D; Kampmiller, T.

    2001-01-01

    The purpose of the study was to ascertain the basic morphologic and kinematic characteristics of elite sprinters. The sample included 24 sprinters, with times over a 100 m distance between 10.21 s and 11.19 s. Morphologic characteristics of the sprinters were measured with a test battery of 17 measures, obtained according to the methodology prescribed by the International Biologic Programme (IBP). The kinematic variables were obtained from a flying start 20 m run and a 20 m run...

  3. Dynamic Control of Kinematically Redundant Robotic Manipulators

    Directory of Open Access Journals (Sweden)

    Erling Lunde

    1987-07-01

    Full Text Available Several methods for task space control of kinematically redundant manipulators have been proposed in the literature. Most of these methods are based on a kinematic analysis of the manipulator. In this paper we propose a control algorithm in which we are especially concerned with the manipulator dynamics. The algorithm is particularly well suited for the class of redundant manipulators consisting of a relatively small manipulator mounted on a larger positioning part.

  4. DIDACTIC AUTOMATED STATION OF COMPLEX KINEMATICS

    Directory of Open Access Journals (Sweden)

    Mariusz Sosnowski

    2014-03-01

    Full Text Available The paper presents the design, control system and software that controls the automated station of complex kinematics. Control interface and software has been developed and manufactured in the West Pomeranian University of Technology in Szczecin in the Department of Automated Manufacturing Systems Engineering and Quality. Conducting classes designed to teach programming and design of structures and systems for monitoring the robot kinematic components with non-standard structures was the reason for installation of the control system and software.

  5. Kinematical coincidence method in transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, L.; Amorini, F. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cardella, G., E-mail: cardella@ct.infn.it [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Chatterjiee, M.B. [Saha Institute for Nuclear Physics, Kolkata (India); De Filippo, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Francalanza, L.; Gianì, R. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Grassi, L. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Rudjer Boskovic Institute, Zagreb (Croatia); Grzeszczuk, A. [Institut of Physics, University of Silesia, Katowice (Poland); La Guidara, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lanzalone, G. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Loria, D.; Minniti, T. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Pagano, E.V. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); and others

    2013-07-01

    A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematics is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of {sup 10}Be+p→{sup 9}Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained. The range of applicability of the method is discussed.

  6. Chiral quark model with relativistic kinematics

    CERN Document Server

    Garcilazo, H

    2003-01-01

    The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.

  7. Geometry and kinematics of the Xianshuihe fault belt in southwestern Sichuan, eastern Tibetan Plateau: Constraints from magnetic fabrics%青藏高原东缘鲜水河断裂带磁组构特征及构造意义

    Institute of Scientific and Technical Information of China (English)

    陈应涛; 张国伟; 鲁如魁; 谢晋强; 郭泱泱

    2013-01-01

    为了探究鲜水河断裂带的几何学、运动学特征,在野外构造、显微构造分析基础上,研究了鲜水河断裂带296块构造岩定向样品的磁组构特征和热磁特征,结果显示样品的平均磁化率km值总体较小,属微弱磁性到弱磁性;热磁实验及其显微构造表明顺磁性的页硅酸盐(如黑云母)等矿物对糜棱岩类样品磁化率贡献较大;磁化率各向异性度PJ总体较大,表明鲜水河断裂带构造变形强烈;磁化率椭球体形状参数T总体大于0,扁率E总体在1附近分布,说明鲜水河断裂带磁化率椭球体以扁圆形为主,整体上磁面理较磁线理发育,进一步显示出鲜水河断裂带构造变形样式以剪切、压扁为主,伴有拉伸的构造变形,同时也反映出鲜水河断裂带多次变形的综合特征;最小磁化率主轴Kmin方位表明鲜水河断裂带北段和南段分别受近EW向和NE-SW向主压应力控制;同时Kmin方位及其倾伏角特征显示鲜水河断裂带总体以左行走滑剪切为主,北段两侧块体在鲜水河断裂带两次不同的构造活动时期,各自有一定的相对抬升,但抬升幅度均不大;南段则是SW块体相对NE块体抬升,抬升幅度较大;整个断裂带特征显示出鲜水河断裂带在向南发展逐渐转化为挤压构造,这可能与青藏高原物质的向东逃逸受阻以及鲜水河断裂带与龙门山断裂带在此交接的地质背景不无关系.%In order to probe into the geometry and kinematics of the Xianshuihe fault belt, this paper carried out a structural deformation characteristics research to the Xianshuihe fault belt through the anisotropy of magnetic susceptibility ( AMS) and thermomagnetic analyses of 296 oriented samples on the basis of the field structural, and microstructural analyses. Average susceptibility ( km ) values of the collected samples are generally small so that they are slightly weak magnetic to weak magnetic. Thermomagnetic curves and

  8. KINEMATIC ANALYSIS OF MODULAR, TRUSS-BASED MANIPULATOR UNITS

    Energy Technology Data Exchange (ETDEWEB)

    Salerno, R. J.

    1994-06-01

    Decontamination and Dismantling (D&D) activities within the U.S. Department of Energy (DOE) require a long reach manipulator with a large load capacity. Variable Geometry Trusses (VGTs) are a unique class of mechanical structures which allow the advantages of truss structures for large scale applications to be applied to large robotic manipulators. Individual VGT units may be assembled to create a modular, long-reach, truss-type manipulator. Each module of such a manipulator system is either a static truss section or one of several possible VGT geometries. While many potential applications exist for this technology, the present work is largely motivated by the need for generic robotic systems for remote manipulation. A manipulator system based on VGT modules provides several advantages. The reconfigurable nature of the manipulator system allows it to be adapted on site to unforeseen conditions. The kinematic redundancy of the manipulator enables it to work effectively even in a highly obstructed workspace. The parallel structure of the truss modules enables the manipulator to be withdrawn in the event of a structural failure. Finally, the open framework of the modules provides a clear, protected passageway for control and power cabling, waste conveyance, or other services required at the end effector. As is implied in a truss structure, all primary members of a VGT are ideally loaded in pure tension or compression. This results in an extremely stiff and strong manipulator system with minimal overall weight. Careful design of the joints of a VGT is very important to the overall stiffness and accuracy of the structure, as several links (as many as six) are joined together at each joint. The greatest disadvantage to this approach to manipulator design has traditionally been that the kinematics of VGT structures are complex and poorly understood. This report specifically addresses the kinematics of several possible geometries for the individual VGT units. Equations and

  9. How the bending kinematics of swimming lampreys build negative pressure fields for suction thrust.

    Science.gov (United States)

    Gemmell, Brad J; Fogerson, Stephanie M; Costello, John H; Morgan, Jennifer R; Dabiri, John O; Colin, Sean P

    2016-12-15

    Swimming animals commonly bend their bodies to generate thrust. For undulating animals such as eels and lampreys, their bodies bend in the form of waves that travel from head to tail. These kinematics accelerate the flow of adjacent fluids, which alters the pressure field in a manner that generates thrust. We used a comparative approach to evaluate the cause-and-effect relationships in this process by quantifying the hydrodynamic effects of body kinematics at the body-fluid interface of the lamprey, Petromyzon marinus, during steady-state swimming. We compared the kinematics and hydrodynamics of healthy control lampreys to lampreys whose spinal cord had been transected mid-body, resulting in passive kinematics along the posterior half of their body. Using high-speed particle image velocimetry (PIV) and a method for quantifying pressure fields, we detail how the active bending kinematics of the control lampreys were crucial for setting up strong negative pressure fields (relative to ambient fields) that generated high-thrust regions at the bends as they traveled all along the body. The passive kinematics of the transected lamprey were only able to generate significant thrust at the tail, relying on positive pressure fields. These different pressure and thrust scenarios are due to differences in how active versus passive body waves generated and controlled vorticity. This demonstrates why it is more effective for undulating lampreys to pull, rather than push, themselves through the fluid. © 2016. Published by The Company of Biologists Ltd.

  10. The photogrammetric inner constraints

    Science.gov (United States)

    Dermanis, Athanasios

    A derivation of the complete inner constraints, which are required for obtaining "free network" solutions in close-range photogrammetry, is presented. The inner constraints are derived analytically for the bundle method, by exploiting the fact that the rows of their coefficient matrix from a basis for the null subspace of the design matrix used in the linearized observation equations. The derivation is independent of any particular choice of rotational parameters and examples are given for three types of rotation angles used in photogrammetry, as well as for the Rodriguez elements. A convenient algorithm based on the use of the S-transformation is presented, for the computation of free solutions with either inner or partial inner constraints. This approach is finally compared with alternative approaches to free network solutions.

  11. Constraint algebra in bigravity

    Energy Technology Data Exchange (ETDEWEB)

    Soloviev, V. O., E-mail: Vladimir.Soloviev@ihep.ru [National Research Center Kurchatov Institute, Institute for High Energy Physics (Russian Federation)

    2015-07-15

    The number of degrees of freedom in bigravity theory is found for a potential of general form and also for the potential proposed by de Rham, Gabadadze, and Tolley (dRGT). This aim is pursued via constructing a Hamiltonian formalismand studying the Poisson algebra of constraints. A general potential leads to a theory featuring four first-class constraints generated by general covariance. The vanishing of the respective Hessian is a crucial property of the dRGT potential, and this leads to the appearance of two additional second-class constraints and, hence, to the exclusion of a superfluous degree of freedom—that is, the Boulware—Deser ghost. The use of a method that permits avoiding an explicit expression for the dRGT potential is a distinctive feature of the present study.

  12. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...... processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what...

  13. Biological constraints do not entail cognitive closure.

    Science.gov (United States)

    Vlerick, Michael

    2014-12-01

    From the premise that our biology imposes cognitive constraints on our epistemic activities, a series of prominent authors--most notably Fodor, Chomsky and McGinn--have argued that we are cognitively closed to certain aspects and properties of the world. Cognitive constraints, they argue, entail cognitive closure. I argue that this is not the case. More precisely, I detect two unwarranted conflations at the core of arguments deriving closure from constraints. The first is a conflation of what I will refer to as 'representation' and 'object of representation'. The second confuses the cognitive scope of the assisted mind for that of the unassisted mind. Cognitive closure, I conclude, cannot be established from pointing out the (uncontroversial) existence of cognitive constraints.

  14. Kinematics of AGN and Quasar Jets

    CERN Document Server

    Kellermann, K I; Homan, D C; Kovalev, Y Y; Kadler, M; Cohen, M C

    2008-01-01

    The major multi-epoch VLBA programs are described and discussed in terms of relativistic beaming models. Broadly speaking the observed kinematics are consistent with models having a parent population which is only mildly relativistic but with Lorentz factors extending up to about 30. While the collimation and acceleration appears to mainly occur close to the central engine, there is evidence of accelerations up to 1 kpc downstream. Generally the motion appears to be linear, but in some sources the motion follows a curved trajectory. In other sources, successive features appear to be ejected in different directions possibly the result of a precessing nozzle. The launch of GLAST in 2008 will offer new opportunities to study the relation between radio and gamma-ray activity, and possibly to locate the source of the gamma-ray emission. VSOP-2 will give enhanced resolution and will facilitate the study of the two-dimensional structure of relativistic jets, while RadioAstron will provide unprecedented resolution to...

  15. Kinematics of the South Atlantic rift

    CERN Document Server

    Heine, Christian; Müller, R Dietmar

    2013-01-01

    The South Atlantic rift basin evolved as branch of a large Jurassic-Cretaceous intraplate rift zone between the African and South American plates during the final breakup of western Gondwana. By quantitatively accounting for crustal deformation in the Central and West African rift zone, we indirectly construct the kinematic history of the pre-breakup evolution of the conjugate West African-Brazilian margins. Our model suggests a causal link between changes in extension direction and velocity during continental extension and the generation of marginal structures such as the enigmatic Pre-salt sag basin and the S\\~ao Paulo High. We model an initial E-W directed extension between South America and Africa (fixed in present-day position) at very low extensional velocities until Upper Hauterivian times ($\\approx$126 Ma) when rift activity along in the equatorial Atlantic domain started to increase significantly. During this initial $\\approx$17 Myr-long stretching episode the Pre-salt basin width on the conjugate Br...

  16. Kinematics of AGN and Quasar Jets

    Science.gov (United States)

    Kellermann, K. I.; Lister, M. L.; Homan, D. C.; Kovalev, Y. Y.; Kadler, M.; Cohen, M. C.

    2009-08-01

    The major multi-epoch VLBA programs are described and discussed in terms of relativistic beaming models. Broadly speaking the observed kinematics are consistent with models having a parent population which is only mildly relativistic but with Lorentz factors extending up to about 30. While the collimation and acceleration appears to mainly occur close to the central engine, there is evidence of accelerations up to 1 kpc downstream. Generally the motion appears to be linear, but in some sources the motion follows a curved trajectory. In other sources, successive features appear to be ejected in different directions possibly the result of a precessing nozzle. The launch of GLAST in 2008 will offer new opportunities to study the relation between radio and gamma--ray activity, and possibly to locate the source of the gamma--ray emission. VSOP-2 will give enhanced resolution and will facilitate the study of the two-dimensional structure of relativistic jets, while RadioAstron will provide unprecedented resolution to study the fine scale structure of the jet base.

  17. Kinematic amplification strategies in plants and engineering

    Science.gov (United States)

    Charpentier, Victor; Hannequart, Philippe; Adriaenssens, Sigrid; Baverel, Olivier; Viglino, Emmanuel; Eisenman, Sasha

    2017-06-01

    While plants are primarily sessile at the organismal level, they do exhibit a vast array of movements at the organ or sub-organ level. These movements can occur for reasons as diverse as seed dispersal, nutrition, protection or pollination. Their advanced mechanisms generate a myriad of movement typologies, many of which are not fully understood. In recent years, there has been a renewal of interest in understanding the mechanical behavior of plants from an engineering perspective, with an interest in developing novel applications by up-sizing these mechanisms from the micro- to the macro-scale. This literature review identifies the main strategies used by plants to create and amplify movements and anatomize the most recent mechanical understanding of compliant engineering mechanics. The paper ultimately demonstrates that plant movements, rooted in compliance and multi-functionality, can effectively inspire better kinematic/adaptive structures and materials. In plants, the actuators and the deployment structures are fused into a single system. The understanding of those natural movements therefore starts with an exploration of mechanisms at the origins of movements. Plant movements, whether slow or fast, active or passive, reversible or irreversible, are presented and detailed for their mechanical significance. With a focus on displacement amplification, the most recent promising strategies for actuation and adaptive systems are examined with respect to the mechanical principles of shape morphing plant tissues.

  18. Kinematic Subduction Rate of Labrador Sea Water

    Science.gov (United States)

    Courtois, P.; Garcia, Y.; Hu, X.; Myers, P. G.

    2016-02-01

    The Labrador Sea (LS) is one of few places where the atmosphere has a direct impact on the deep ocean. During strong winters, the heat loss at the surface of Labrador Sea preconditions the cooling process, disrupts the stratified water column, producing a uniformly denser water mass. This process is called deep convection and is characterized by the production of Labrador Sea Water(LSW), which in turn contributes, from a larger scale, to the lower limb of the Meridional Overturning Circulation (MOC). Due to higher anthropogenic activities, resulting in a warmer environment, freshwater input (e.g. Greenland runoff, sea­ice melting, etc.) in the LS has increased in the past decades. This has a strong impact on the ocean ventilation as it restratifies the water column and prevents the convection process.The mixed layer at the surface of the ocean is often considered as an interface between the atmosphere and the deep ocean. In the LS, the depth of the mixed layer (MLD) is greatly affected by the seasonal cycle, the freshwater input, and local processes such as the deep convection. A way to study the ventilation process in the LS is to use a kinematic approach to calculate the subduction rate, which is the vertical transport of a water mass from the mixed layer into the permanent thermocline.In this study, we present our results on the subduction rate for a different range of LSW, using the Nucleus for European Modelling of the Ocean (NEMO) numerical model.

  19. Spectroscopic signatures of youth in low-mass kinematic candidates of young moving groups

    CERN Document Server

    Gálvez-Ortiz, M C; Clarke, J R A; Pavlenko, Ya V; Folkes, S L; Pinfield, D J; Jones, H R A; Jenkins, J S; Barnes, J R; Burningham, B; Day-Jones, A C; Martín, E L; Pérez, A E García; del Burgo, C; Pokorny, R S

    2014-01-01

    We present a study of age-related spectral signatures observed in 25 young low-mass objects that we have previously determined as possible kinematic members of five young moving groups: the Local Association (Pleiades moving group, age=20 - 150 Myr), the Ursa Major group (Sirius supercluster, age=300 Myr), the Hyades supercluster (age=600 Myr), IC 2391 supercluster (age=35--55 Myr) and the Castor moving group (age=200 Myr). In this paper we characterize the spectral properties of observed high or low resolution spectra of our kinematic members by fitting theoretical spectral distributions. We study signatures of youth, such as lithium {\\sc i} 6708 \\AA, H$\\alpha$ emission and other age-sensitive spectroscopic signatures in order to confirm the kinematic memberships through age constraints. We find that 21 ($84\\%$) targets show spectroscopic signatures of youth in agreement with the age ranges of the moving group to which membership is implied. For two further objects, age-related constraints remain difficult t...

  20. Constraints as evolutionary systems

    CERN Document Server

    Rácz, István

    2016-01-01

    The constraint equations for smooth $[n+1]$-dimensional (with $n\\geq 3$) Riemannian or Lorentzian spaces satisfying the Einstein field equations are considered. It is shown, regardless of the signature of the primary space, that the constraints can be put into the form of an evolutionary system comprised either by a first order symmetric hyperbolic system and a parabolic equation or, alternatively, by a strongly hyperbolic system and a subsidiary algebraic relation. In both cases the (local) existence and uniqueness of solutions are also discussed.

  1. The warm ionized gas in CALIFA early-type galaxies: 2D emission-line patterns and kinematics for 32 galaxies

    CERN Document Server

    Gomes, J M; Kehrig, C; Vílchez, J M; Lehnert, M D; Sánchez, S F; Ziegler, B; Breda, I; Reis, S N dos; Iglesias-Páramo, J; Bland-Hawthorn, J; Galbany, L; Bomans, D J; Rosales-Ortega, F F; Fernandes, R Cid; Walcher, C J; Falcón-Barroso, J; García-Benito, R; Márquez, I; del Olmo, A; Masegosa, J; Mollá, M; Marino, R A; Delgado, R M González; López-Sánchez, Á R

    2015-01-01

    The morphological, spectroscopic and kinematical properties of the warm interstellar medium (wim) in early-type galaxies (ETGs) hold key observational constraints to nuclear activity and the buildup history of these massive, quiescent systems. High-quality integral field spectroscopy (IFS) data with a wide spectral and spatial coverage, such as those from the CALIFA survey, offer an unprecedented opportunity for advancing our understanding of the wim in ETGs. This article centers on a 2D investigation of the wim component in 32 nearby (<~150Mpc) ETGs from CALIFA, complementing a previous 1D analysis of the same sample (Papaderos et al. 2013; P13). We include here H\\alpha\\ intensity and equivalent width (EW) maps and radial profiles, diagnostic emission-line ratios, besides ionized-gas and stellar kinematics. This study is supplemented by \\tau-ratio maps as an efficient means to quantify the role of photoionization by pAGB stars, as compared to other mechanisms (e.g., AGN, low-level star formation). Additio...

  2. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  3. Analysis and Experimental Kinematics of a Skid-Steering Wheeled Robot Based on a Laser Scanner Sensor

    Directory of Open Access Journals (Sweden)

    Tianmiao Wang

    2015-04-01

    Full Text Available Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable  and robot speed , including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model’s stationary response for the vehicle shows a qualitative relationship for the specified parameters  and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient  and two physical factors is studied, i.e., the radius of the path curvature  and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid–steering robot.

  4. Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics

    CERN Document Server

    Adams, Joshua J; Fabricius, Maximilian H; Bosch, Remco C E van den; Barentine, John C; Bender, Ralf; Gebhardt, Karl; Hill, Gary J; Murphy, Jeremy D; Swaters, R A; Thomas, Jens; van de Ven, Glenn

    2014-01-01

    We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high resolution integral field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although 2/7 galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, gamma, are generally robust. The mean and standard deviation of the logarithmic slope for the population are gamma=0.67+/-0.10 when measured in the stars and gamma=0.58+/-0.24 when measured in the gas. We als...

  5. Spectroscopy and kinematics of low-mass members of young moving groups

    CERN Document Server

    Galvez-Ortiz, M C; Pinfield, D J; Jenkins, J S; Folkes, S L; Perez, A E Garcia; Day-Jones, A C; Burningham, B; Jones, H R A; Barnes, J R; Pokorny, R S

    2010-01-01

    We study a target sample of 68 low-mass objects (with spectral types in the range M4.5-L1) previously selected via photometric and astrometric criteria, as possible members of five young moving groups: the Local Association (Pleiades moving group, age=20 - 150 Myr), the Ursa Mayor group (Sirius supercluster, age=300 Myr), the Hyades supercluster (age=600 Myr), IC 2391 supercluster (age=35 - 55 Myr) and the Castor moving group (age=200 Myr). In this paper we assess their membership by using different kinematic and spectroscopic criteria. We use high resolution echelle spectroscopic observations of the sample to measure accurate radial velocities (RVs). Distances are calculated and compared to those of the moving group from the literature, we also calculate the kinematic Galactic components (U,V,W) of the candidate members and apply kinematic criterion of membership to each group. In addition we measure rotational velocities (v sin i) to place further constraints on membership of kinematic members. We find that...

  6. Kinematic analysis of cable-driven parallel mechanisms based on minimum potential energy principle

    Directory of Open Access Journals (Sweden)

    Guan Liwen

    2015-12-01

    Full Text Available The forward kinematic analysis of the cable-driven parallel mechanism has been a challenging and interesting problem since 10 years ago. This work converts the forward kinematic analysis problem of the cable-driven parallel mechanism to an optimization problem, whose objective is to minimize the potential energy of mobile platform. In order to simplify the optimization problem further so that it can be solved with any simple optimization algorithm in short time, some constraints are introduced to design variables. We utilize the sequential quadratic programming algorithm to solve the simplified optimization problem in this article. The efficiency and effectiveness of the proposed approach are validated with some numerical examples. Furthermore, due to the fact that a required pose may be not stable, the availability of its inverse kinematic solution should be supervised. The aforementioned approach provides a valid tool for solving this type of problems by contrasting the distinction between the required pose and the actual pose calculated by it. The feasibility of applying our proposed method to execute the inverse kinematic analysis of cable-driven parallel mechanism is proved with several examples in this article.

  7. Effects of contracture on gait kinematics: A systematic review.

    Science.gov (United States)

    Attias, Michael; Chevalley, Odile; Bonnefoy-Mazure, Alice; De Coulon, Geraldo; Cheze, Laurence; Armand, Stéphane

    2016-03-01

    Contractures of a major joint in the lower limbs may impair human walking in addition to other daily living activities. A contracture is defined as the inability of a joint to perform the full range of motion and excessive resistance during passive mobilization of the joint. Few studies have reported methods describing how to evaluate contractures. Understanding the association among all of these studies seems essential to improve patient management. Therefore, we conducted a systematic review on this topic to elucidate the influence of contractures on gait kinematics. An electronic search in the literature will be conducted. Studies were screened by title and abstract and full texts were evaluated secondarily for definitive inclusion. The quality of the included studies was assessed independently by the two review authors with the Modified Quality Assessment Checklist. The included studies were separated into three categories: pathological contracture versus healthy controls (descriptive), simulated contracture versus healthy controls (experimental), and pre- and post-kinematics after surgical muscle lengthening (surgery). From a total of 4402 references, 112 original articles were selected, and 28 studies were identified in this systematic review. No significant difference between raters was observed on the total score of the Modified Quality Assessment Checklist. Contractures influence walking depending on the location (muscle) and the contracture level (muscle-tendon length). After giving a definition of contracture, this review identified some contracture alterations, such as plantarflexion, knee flexion and hip flexion contractures, with a kinematic description and presented possible different compensations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Kinematic and ground reaction force accommodation during weighted walking.

    Science.gov (United States)

    James, C Roger; Atkins, Lee T; Yang, Hyung Suk; Dufek, Janet S; Bates, Barry T

    2015-12-01

    Weighted walking is a functional activity common in daily life and can influence risks for musculoskeletal loading, injury and falling. Much information exists about weighted walking during military, occupational and recreational tasks, but less is known about strategies used to accommodate to weight carriage typical in daily life. The purposes of the study were to examine the effects of weight carriage on kinematics and peak ground reaction force (GRF) during walking, and explore relationships between these variables. Twenty subjects walked on a treadmill while carrying 0, 44.5 and 89 N weights in front of the body. Peak GRF, sagittal plane joint/segment angular kinematics, stride length and center of mass (COM) vertical displacement were measured. Changes in peak GRF and displacement variables between weight conditions represented accommodation. Effects of weight carriage were tested using analysis of variance. Relationships between peak GRF and kinematic accommodation variables were examined using correlation and regression. Subjects were classified into sub-groups based on peak GRF responses and the correlation analysis was repeated. Weight carriage increased peak GRF by an amount greater than the weight carried, decreased stride length, increased vertical COM displacement, and resulted in a more extended and upright posture, with less hip and trunk displacement during weight acceptance. A GRF increase was associated with decreases in hip extension (|r|=.53, p=.020) and thigh anterior rotation (|r|=.57, p=.009) displacements, and an increase in foot anterior rotation displacement (|r|=.58, p=.008). Sub-group analysis revealed that greater GRF increases were associated with changes at multiple sites, while lesser GRF increases were associated with changes in foot and trunk displacement. Weight carriage affected walking kinematics and revealed different accommodation strategies that could have implications for loading and stability.

  9. Constraint Optimization Literature Review

    Science.gov (United States)

    2015-11-01

    COPs. 15. SUBJECT TERMS high-performance computing, mobile ad hoc network, optimization, constraint, satisfaction 16. SECURITY CLASSIFICATION OF: 17...France): INRA Editions; 1996. p. 111–150. Black PE. Branch-and-bound. US national institute of standards and technology dictionary of algorithms

  10. Gait in adolescent idiopathic scoliosis: kinematics and electromyographic analysis.

    Science.gov (United States)

    Mahaudens, P; Banse, X; Mousny, M; Detrembleur, C

    2009-04-01

    Adolescent idiopathic scoliosis (AIS) is a progressive growth disease that affects spinal anatomy, mobility, and left-right trunk symmetry. Consequently, AIS can modify human locomotion. Very few studies have investigated a simple activity like walking in a cohort of well-defined untreated patients with scoliosis. The first goal of this study is to evaluate the effects of scoliosis and scoliosis severity on kinematic and electromyographic (EMG) gait variables compared to an able-bodied population. The second goal is to look for any asymmetry in these parameters during walking. Thirteen healthy girls and 41 females with untreated AIS, with left thoracolumbar or lumbar primary structural curves were assessed. AIS patients were divided into three clinical subgroups (group 1 40 degrees). Gait analysis included synchronous bilateral kinematic and EMG measurements. The subjects walked on a treadmill at 4 km/h (comfortable speed). The tridimensional (3D) shoulder, pelvis, and lower limb motions were measured using 22 reflective markers tracked by four infrared cameras. The EMG timing activity was measured using bipolar surface electrodes on quadratus lumborum, erector spinae, gluteus medius, rectus femoris, semitendinosus, tibialis anterior, and gastrocnemius muscles. Statistical comparisons (ANOVA) were performed across groups and sides for kinematic and EMG parameters. The step length was reduced in AIS compared to normal subjects (7% less). Frontal shoulder, pelvis, and hip motion and transversal hip motion were reduced in scoliosis patients (respectively, 21, 27, 28, and 22% less). The EMG recording during walking showed that the quadratus lumborum, erector spinae, gluteus medius, and semitendinosus muscles contracted during a longer part of the stride in scoliotic patients (46% of the stride) compared with normal subjects (35% of the stride). There was no significant difference between scoliosis groups 1, 2, and 3 for any of the kinematic and EMG parameters, meaning

  11. Mining Matters : Natural Resource Extraction and Local Business Constraints

    NARCIS (Netherlands)

    de Haas, Ralph; Poelhekke, Steven

    2016-01-01

    We estimate the impact of local mining activity on the business constraints experienced by 22,150 firms across eight resource-rich countries. We find that with the presence of active mines, the business environment in the immediate vicinity (<20 km) of a firm deteriorates but business constraints of

  12. Mining Matters : Natural Resource Extraction and Local Business Constraints

    NARCIS (Netherlands)

    de Haas, Ralph; Poelhekke, Steven

    2016-01-01

    We estimate the impact of local mining activity on the business constraints experienced by 22,150 firms across eight resource-rich countries. We find that with the presence of active mines, the business environment in the immediate vicinity (<20 km) of a firm deteriorates but business constraints of

  13. Effects of robotically modulating kinematic variability on motor skill learning and motivation.

    Science.gov (United States)

    Duarte, Jaime E; Reinkensmeyer, David J

    2015-04-01

    It is unclear how the variability of kinematic errors experienced during motor training affects skill retention and motivation. We used force fields produced by a haptic robot to modulate the kinematic errors of 30 healthy adults during a period of practice in a virtual simulation of golf putting. On day 1, participants became relatively skilled at putting to a near and far target by first practicing without force fields. On day 2, they warmed up at the task without force fields, then practiced with force fields that either reduced or augmented their kinematic errors and were finally assessed without the force fields active. On day 3, they returned for a long-term assessment, again without force fields. A control group practiced without force fields. We quantified motor skill as the variability in impact velocity at which participants putted the ball. We quantified motivation using a self-reported, standardized scale. Only individuals who were initially less skilled benefited from training; for these people, practicing with reduced kinematic variability improved skill more than practicing in the control condition. This reduced kinematic variability also improved self-reports of competence and satisfaction. Practice with increased kinematic variability worsened these self-reports as well as enjoyment. These negative motivational effects persisted on day 3 in a way that was uncorrelated with actual skill. In summary, robotically reducing kinematic errors in a golf putting training session improved putting skill more for less skilled putters. Robotically increasing kinematic errors had no performance effect, but decreased motivation in a persistent way.

  14. Consideration of Photon Radiation in Kinematic Fits for Future e+ e- Colliders

    CERN Document Server

    Beckmann, Moritz; List, Jenny

    2010-01-01

    Kinematic fitting is an important tool to improve the resolution in high-energy physics experiments. At future e+e- colliders, photon radiation parallel to the beam carrying away large amounts of energy and momentum will become a challenge for kinematic fitting. A photon with longitudinal momentum pz({\\eta}) is introduced, which is parametrized such that {\\eta} follows a normal distribution. In the fit, {\\eta} is treated as having a measured value of zero, which corresponds to pz = 0. As a result, fits with constraints on energy and momentum conservation converge well even in the presence of a highly energetic photon, while the resolution of fits without such a photon is retained. A fully simulated and reconstructed e+e- -> qqqq event sample at sqrt(s) = 500 GeV is used to investigate the performance of this method under realistic conditions, as expected at the International Linear Collider.

  15. Kinematic Analysis of a Serial - Parallel Machine Tool: the VERNE machine

    CERN Document Server

    Kanaan, Daniel; Chablat, Damien; 10.1016/j.mechmachtheory.2008.03.002

    2008-01-01

    The paper derives the inverse and the forward kinematic equations of a serial - parallel 5-axis machine tool: the VERNE machine. This machine is composed of a three-degree-of-freedom (DOF) parallel module and a two-DOF serial tilting table. The parallel module consists of a moving platform that is connected to a fixed base by three non-identical legs. These legs are connected in a way that the combined effects of the three legs lead to an over-constrained mechanism with complex motion. This motion is defined as a simultaneous combination of rotation and translation. In this paper we propose symbolical methods that able to calculate all kinematic solutions and identify the acceptable one by adding analytical constraint on the disposition of legs of the parallel module.

  16. Kinematic and Dynamic Simulation Analysis of Hydraulic Excavator’s Working Equipment based on ADAMS

    Directory of Open Access Journals (Sweden)

    Yu Hong Yan

    2016-01-01

    Full Text Available This paper establishes the 3D excavator model according to the actual size in UG firstly. Then based on the virtual simulation software ADAMS, the virtual prototype of the working device is built by adding interrelated constraints(kinematic pair and hydraulic cylinder driving function and load secondly. This paper gets the main parameters of the excavator working scope and the pressure situation change curves of point of each hydraulic cylinder by making kinematic and dynamic simulation analysis of hydraulic excavator’s working equipment at last. The conclusion providing design theory and improvement for the excavator’s working device, which also play an important role in improving the level of China’s excavator design, enhancing excavator’s performance and promoting the rapid development of excavator industry.

  17. Kinematics and dynamics analysis of a novel 2PC-CPR parallel mechanism

    Directory of Open Access Journals (Sweden)

    Sheng Lin

    2016-10-01

    Full Text Available A novel parallel mechanism of two translations and one rotation freedom degrees two-prismatic joint-cylindrical joint-one-cylindrical joint-prismatic joint-revolute joint (2PC-CPR is proposed. The mechanism can be applied to write Chinese characters and to classify productions with the appropriated control. In this article, the kinematics and dynamics analysis are systematically conducted with the following procedure. First of all, the 2PC-CPR parallel mechanism is designed by GF set and the freedom degree of the mechanism is calculated using screw theory. Then the formula for solving the inverse/forward displacement, velocity, and acceleration is derived based on the geometrical constraints. The dynamics model is established by using virtual work principle. Finally, kinematics SimMechanics model is created by the co-simulation of SolidWorks and MATLAB software, and its workspace is analyzed.

  18. Space reconstruction of the morphology and kinematics of axisymmetric radio sources

    CERN Document Server

    Diep, P N; Hoai, D T; Nhung, P T; Thao, N T; Tuan-Anh, P; Darriulat, P

    2016-01-01

    The unprecedented quality of the observations available from the Atacama Large Millimetre/sub-millimetre Array (ALMA) calls for analysis methods making the best of them. Reconstructing in space the morphology and kinematics of radio sources is an underdetermined problem that requires imposing additional constraints for its solution. The hypothesis of rotational invariance about a well-defined star axis, which is a good approximation to the description of the gas envelopes of many evolved stars and protostars, is particularly efficient in this role. In the first part of the article, a systematic use of simulated observations allows for identifying the main problems and for constructing quantities aimed at solving them. In particular the evaluation of the orientation of the star axis in space and the differentiation between expansion along the star axis and rotation about it are given special attention. The use of polar rather than Cartesian sky coordinates is shown to better match the morphology and kinematics...

  19. Autonomous gliding entry guidance with geographic constraints

    Institute of Scientific and Technical Information of China (English)

    Guo Jie; Wu Xuzhong; Tang Shengjing

    2015-01-01

    This paper presents a novel three-dimensional autonomous entry guidance for relatively high lift-to-drag ratio vehicles satisfying geographic constraints and other path constraints. The guidance is composed of onboard trajectory planning and robust trajectory tracking. For trajectory planning, a longitudinal sub-planner is introduced to generate a feasible drag-versus-energy profile by using the interpolation between upper boundary and lower boundary of entry corridor to get the desired trajectory length. The associated magnitude of the bank angle can be specified by drag profile, while the sign of bank angle is determined by lateral sub-planner. Two-reverse mode is utilized to satisfy waypoint constraints and dynamic heading error corridor is utilized to satisfy no-fly zone constraints. The longitudinal and lateral sub-planners are iteratively employed until all of the path constraints are satisfied. For trajectory tracking, a novel tracking law based on the active disturbance rejection control is introduced. Finally, adaptability tests and Monte Carlo simulations of the entry guidance approach are performed. Results show that the proposed entry guidance approach can adapt to different entry missions and is able to make the vehicle reach the prescribed target point precisely in spite of geographic constraints.

  20. KINEMATIC AND SPATIAL SUBSTRUCTURE IN NGC 2264

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, John J. [Hubble Fellow, National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Hartmann, Lee; Hsu, Wen-Hsin; Mateo, Mario [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Fűrész, Gabor, E-mail: tobin@strw.leidenuniv.nl [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-04-15

    We present an expanded kinematic study of the young cluster NGC 2264 based upon optical radial velocities measured using multi-fiber echelle spectroscopy at the 6.5 m MMT and Magellan telescopes. We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Fűrész et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas. In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular ({sup 13}CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon. Our results emphasize the complexity of the spatial and kinematic structure of NGC 2264, important for eventually building up a comprehensive picture of cluster formation.

  1. A constraint algorithm for singular Lagrangians subjected to nonholonomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    de Leon, M. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); de Diego, D.M. [Departamento de Economia Aplicada Cuantitativa, Facultad de Ciencias Economicas y Empresariales, UNED, 28040 Madrid (Spain)

    1997-06-01

    We construct a constraint algorithm for singular Lagrangian systems subjected to nonholonomic constraints which generalizes that of Dirac for constrained Hamiltonian systems. {copyright} {ital 1997 American Institute of Physics.}

  2. Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking

    Directory of Open Access Journals (Sweden)

    Min Su Lee

    2015-11-01

    Full Text Available In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT-based pedestrian dead reckoning (PDR and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE with respect to walking distance is achieved.

  3. Lepton number violation at colliders from kinematically inaccessible gauge bosons

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Richard [Durham University, Department of Physics, Institute for Particle Physics Phenomenology (IPPP), Durham (United Kingdom); DARC, Durham (United Kingdom)

    2017-06-15

    We reevaluate the necessity of W{sub R} gauge bosons being kinematically accessible to test the left-right symmetric model (LRSM) at hadron colliders. In the limit that W{sub R} are too heavy, resonant production of sub-TeV Majorana neutrinos N can still proceed at the Large Hadron Collider (LHC) via the process pp → W{sub R}{sup ±*} → Nl{sup ±} → l{sup ±}l{sup ±} + nj if mediated by a far off-shell W{sub R}. Traditional searches strategies are insensitive to this regime as they rely on momenta of final states scaling with TeV-scale M{sub W{sub R}}. For such situations, the process is actually kinematically and topologically identical to the direct production (DP) process pp → W{sub SM}{sup ±*} → Nl{sup ±} → l{sup ±}l{sup ±} + nj. In this context, we reinterpret √(s) = 8 TeV LHC constraints on DP rates for the minimal LRSM. For m{sub N} = 200-500 GeV and right-left coupling ratio κ{sub R} = g{sub R}/g{sub L}, we find (M{sub W{sub R}}/κ{sub R}) > 1.1-1.8 TeV at 95% CLs. Expected sensitivities to DP at 14 (100) TeV are also recast: with L = 1 (10) ab{sup -1}, one can probe (M{sub W{sub R}}/κ{sub R}) < 7.9-8.9 (14-40) TeV for m{sub N} = 100-700 (1200) GeV, well beyond the anticipated sensitivity of resonant W{sub R} searches. Findings in terms of gauge invariant dimension-six operators with heavy N are also reported. (orig.)

  4. Identifying the Isomorphism of Kinematic Chains

    Directory of Open Access Journals (Sweden)

    Romaniak Krystyna

    2016-09-01

    Full Text Available Identification of isomorphic kinematic chains is one of the key issues in researching the structure of mechanisms. As a result the structures which duplicate are eliminated and further research is carried out on kinematic chains that do not duplicate. This dilemma has been taken up by many scholars who have come up with a variety of ideas how to solve it. The review of the methods for identifying the isomorphism of kinematic chains suggested by researchers is contained in this study, including Hamming Number Technique, eigenvalues and eigenvectors, perimeter graphs, dividing and matching vertices. The spectrum of methods applied to the issue of identifying the iso-morphism of mechanisms reflects the researchers’ efforts to obtain a precise result in the shortest time possible.

  5. Kinematics of the most efficient cilium

    CERN Document Server

    Eloy, Christophe

    2012-01-01

    In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although cilia have a remarkably conserved internal molecular structure, experimental observations report very diverse kinematics. To address this diversity, we determine numerically the kinematics and energetics of the most efficient cilium. Specifically, we compute the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost, where the cost is taken to be the positive work done by all internal molecular motors. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number, and closely resemble the two-stroke ciliary beating pattern observed experimentally.

  6. SMACK - SMOOTHING FOR AIRCRAFT KINEMATICS

    Science.gov (United States)

    Bach, R.

    1994-01-01

    The computer program SMACK (SMoothing for AirCraft Kinematics) is designed to provide flightpath reconstruction of aircraft forces and motions from measurements that are noisy or incomplete. Additionally, SMACK provides a check on instrument accuracy and data consistency. The program can be used to analyze data from flight-test experiments prior to their use in performance, stability and control, or aerodynamic modeling calculations. It can also be used in the analysis of aircraft accidents, where the actual forces and motions may have to be determined from a very limited data set. Application of a state-estimation method for flightpath reconstruction is possible because aircraft forces and motions are related by well-known equations of motion. The task of postflight state estimation is known as a nonlinear, fixed-interval smoothing problem. SMACK utilizes a backward-filter, forward-smoother algorithm to solve the problem. The equations of motion are used to produce estimates that are compared with their corresponding measurement time histories. The procedure is iterative, providing improved state estimates until a minimum squared-error measure is achieved. In the SMACK program, the state and measurement models together represent a finite-difference approximation for the six-degree-of-freedom dynamics of a rigid body. The models are used to generate time histories which are likely to be found in a flight-test measurement set. These include onboard variables such as Euler angles, angular rates, and linear accelerations as well as tracking variables such as slant range, bearing, and elevation. Any bias or scale-factor errors associated with the state or measurement models are appended to the state vector and treated as constant but unknown parameters. The SMACK documentation covers the derivation of the solution algorithm, describes the state and measurement models, and presents several application examples that should help the analyst recognize the potential

  7. Auditory coding of human movement kinematics.

    Science.gov (United States)

    Vinken, Pia M; Kröger, Daniela; Fehse, Ursula; Schmitz, Gerd; Brock, Heike; Effenberg, Alfred O

    2013-01-01

    Although visual perception is dominant on motor perception, control and learning, auditory information can enhance and modulate perceptual as well as motor processes in a multifaceted manner. During last decades new methods of auditory augmentation had been developed with movement sonification as one of the most recent approaches expanding auditory movement information also to usually mute phases of movement. Despite general evidence on the effectiveness of movement sonification in different fields of applied research there is nearly no empirical proof on how sonification of gross motor human movement should be configured to achieve information rich sound sequences. Such lack of empirical proof is given for (a) the selection of suitable movement features as well as for (b) effective kinetic-acoustical mapping patterns and for (c) the number of regarded dimensions of sonification. In this study we explore the informational content of artificial acoustical kinematics in terms of a kinematic movement sonification using an intermodal discrimination paradigm. In a repeated measure design we analysed discrimination rates of six everyday upper limb actions to evaluate the effectiveness of seven different kinds of kinematic-acoustical mappings as well as short-term learning effects. The kinematics of the upper limb actions were calculated based on inertial motion sensor data and transformed into seven different sonifications. Sound sequences were randomly presented to participants and discrimination rates as well as confidence of choice were analysed. Data indicate an instantaneous comprehensibility of the artificial movement acoustics as well as short-term learning effects. No differences between different dimensional encodings became evident thus indicating a high efficiency for intermodal pattern discrimination for the acoustically coded velocity distribution of the actions. Taken together movement information related to continuous kinematic parameters can be

  8. Hand kinematics of piano playing.

    Science.gov (United States)

    Furuya, Shinichi; Flanders, Martha; Soechting, John F

    2011-12-01

    Dexterous use of the hand represents a sophisticated sensorimotor function. In behaviors such as playing the piano, it can involve strong temporal and spatial constraints. The purpose of this study was to determine fundamental patterns of covariation of motion across joints and digits of the human hand. Joint motion was recorded while 5 expert pianists played 30 excerpts from musical pieces, which featured ∼50 different tone sequences and fingering. Principal component analysis and cluster analysis using an expectation-maximization algorithm revealed that joint velocities could be categorized into several patterns, which help to simplify the description of the movements of the multiple degrees of freedom of the hand. For the thumb keystroke, two distinct patterns of joint movement covariation emerged and they depended on the spatiotemporal patterns of the task. For example, the thumb-under maneuver was clearly separated into two clusters based on the direction of hand translation along the keyboard. While the pattern of the thumb joint velocities differed between these clusters, the motions at the metacarpo-phalangeal and proximal-phalangeal joints of the four fingers were more consistent. For a keystroke executed with one of the fingers, there were three distinct patterns of joint rotations, across which motion at the striking finger was fairly consistent, but motion of the other fingers was more variable. Furthermore, the amount of movement spillover of the striking finger to the adjacent fingers was small irrespective of the finger used for the keystroke. These findings describe an unparalleled amount of independent motion of the fingers.

  9. Dynamical Constraints on Exoplanets

    CERN Document Server

    Horner, Jonti; Tinney, Chris; Hinse, Tobias C; Marshall, Jonathan P

    2013-01-01

    Dynamical studies of new exoplanet systems are a critical component of the discovery and characterisation process. Such studies can provide firmer constraints on the parameters of the newly discovered planets, and may even reveal that the proposed planets do not stand up to dynamical scrutiny. Here, we demonstrate how dynamical studies can assist the characterisation of such systems through two examples: QS Virginis and HD 73526.

  10. (non) Emergent Constraints

    Science.gov (United States)

    Jackson, C. S.; Hattab, M. W.; Huerta, G.

    2014-12-01

    Emergent constraints are observable quantities that provide some physical basis for testing or predicting how a climate model will respond to greenhouse gas forcing. Very few such constraints have been identified for the multi-model CMIP archive. Here we explore the question of whether constraints that apply to a single model, a perturbed parameter ensemble (PPE) of the Community Atmosphere Model (CAM3.1), can be applied to predicting the climate sensitivities of models within the CMIP archive. In particular we construct our predictive patterns from multivariate EOFs of the CAM3.1 ensemble control climate. Multiple regressive statistical models were created that do an excellent job of predicting CAM3.1 sensitivity to greenhouse gas forcing. However, these same patterns fail spectacularly to predict sensitivities of models within the CMIP archive. We attribute this failure to several factors. First, and perhaps the most important, is that the structures affecting climate sensitivity in CAM3.1 have a unique signature in the space of our multivariate EOF patterns that are unlike any other climate model. That is to say, we should not expect CAM3.1 to represent the way another models within CMIP archive respond to greenhouse gas forcing. The second, perhaps related, reason is that the CAM3.1 PPE does a poor job of spanning the range of climates and responses found within the CMIP archive. We shall discuss the implications of these results for the prospect of finding emergent constraints within the CMIP archive. We will also discuss what this may mean for establishing uncertainties in climate projections.

  11. The NCL natural constraint language

    CERN Document Server

    Zhou, Jianyang

    2012-01-01

    This book presents the Natural Constraint Language (NCL) language, a description language in conventional mathematical logic for modeling and solving constraint satisfaction problems. It uses illustrations and tutorials to detail NCL and its applications.

  12. Structure and Kinematics of the Indo-Burmese Wedge

    Science.gov (United States)

    Maurin, T.; Rangin, C.

    2007-12-01

    The Burma subduction trench and the associated Indo Burmese wedge mark the present eastern boundary of the Indian plate in the northern Bengal area. The initiation, duration and history of the Bengal crust subduction beneath Burma is still debated. The aim of this paper is to provide a structural and kinematic analysis of the Indo- Burmese wedge in order to better constraints the Bengal crust subduction history beneath Burma. On the basis of field observations, seismic reflection data interpretation and well logs data we present a structural analysis of the Outer Indo-Burmese Wedge. We also constrain the onset of this Outer Wedge to be younger than 2Ma, implying a recent and fast westward growth (~10cm/yr) since Late Pliocene in close relationship with the onset of the Shillong plateau. Restoration process of a synthetic cross section through the Outer Wedge allowed us to estimate the amount of EW shortening accommodated in the Outer Wedge to be 5.1mm/yr since 2Ma. These results combined with previous available GPS data from central Myanmar suggest strain partitioning at wedge scale. The core of the wedge is affected by shear deformation and acts as a buttress for a frontal wedge that accommodates a more compressive strain component. Finally we propose that the main characteristic of the Indo-Burmese wedge growth mechanism is the progressive incorporation of the most internal part of the wedge, formerly affected by transpressive thin-skinned tectonics, to the buttress where they are subsequently affected by shear deformation. The crustal structure boarding the newly formed buttress seems to be guided by the subducting crust fabrics. We are in favour of a very recent (Late Miocene) onset of the present Indian crust subduction beneath Burma coeval with the global plate kinematics reorganisation related to the Indian/Australian plate spliting. This subduction postdates the Indo Burmese range onset that must have started in early Miocene. This range first began to

  13. H$\\alpha$ kinematics of KPG 390

    CERN Document Server

    Repetto, P; Fuentes-Carrera, R Gabbasov I

    2009-01-01

    In this work we present scanning Fabry-Perot H$\\alpha$ observations of the isolated interacting galaxy pair NGC 5278/79 obtained with the PUMA Fabry-Perot interferometer. We derived velocity fields, various kinematic parameters and rotation curves for both galaxies. Our kinematical results together with the fact that dust lanes have been detected in both galaxies, as well as the analysis of surface brightness profiles along the minor axis, allowed us to determine that both components of the interacting pair are trailing spirals.

  14. The Kinematic Theory of Solar Dynamo

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Generation of the Sun's magnetic fields by self-inductive processes inthe solar electrically conducting interior, the solar dynamo theory, is a fundamen-tally important subject in astrophysics. The kinematic dynamo theory concernshow the magnetic fields are produced by kinematically possible flows without beingconstrained by the dynamic equation. We review a number of basic aspects of thekinematic dynamo theory, including the magnetohydrodynamic approximation forthe dynamo equation, the impossibility of dynamo action with the solar differentialrotation, the Cowling's anti-dynamo theorem in the solar context, the turbulent al-pha effect and recently constructed three-dimensional interface dynamos controlledby the solar tachocline at the base of the convection zone.

  15. Inverse Kinematics of a Serial Robot

    Directory of Open Access Journals (Sweden)

    Amici Cinzia

    2016-01-01

    Full Text Available This work describes a technique to treat the inverse kinematics of a serial manipulator. The inverse kinematics is obtained through the numerical inversion of the Jacobian matrix, that represents the equation of motion of the manipulator. The inversion is affected by numerical errors and, in different conditions, due to the numerical nature of the solver, it does not converge to a reasonable solution. Thus a soft computing approach is adopted to mix different traditional methods to obtain an increment of algorithmic convergence.

  16. Kinematic Distance of Galactic Planetary Nebulae

    CERN Document Server

    Yang, A Y; Zhu, H; Leahy, D A; Wu, D

    2016-01-01

    We construct \\HI~absorption spectra for 18 planetary nebulae (PNe) and their background sources using the data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNe, among which 15 objects' kinematic distances are obtained for the first time. The distance uncertainties of 13 PNe range from 10% to 50%, which is a significant improvement with uncertainties of a factor two or three smaller than most of previous distance measurements. We confirm that PN G030.2-00.1 is not a PN because of its large distance found here.

  17. Constraints on Relaxion Windows

    CERN Document Server

    Choi, Kiwoon

    2016-01-01

    We examine low energy phenomenology of the relaxion solution to the weak scale hierarchy problem. Assuming that the Hubble friction is responsible for the dissipation of relaxion energy, we identify the cosmological relaxion window which corresponds to the parameter region compatible with a given value of the acceptable number of inflationary $e$-foldings. We then discuss a variety of observational constraints on the relaxion window, while focusing on the case that the barrier potential to stabilize the relaxion is induced by new physics, rather than by low energy QCD dynamics. We find that majority of the parameter space with a relaxion mass $m_\\phi\\gtrsim 100$ eV or a relaxion decay constant $f\\lesssim 10^7$ GeV is excluded by existing constraints. There is an interesting small parameter region with $m_\\phi\\sim \\,0.2-1$ GeV and $f\\sim\\, {\\rm few}-10$ TeV, which is allowed by existing constraints, but can be probed soon by future beam dump experiment such as the SHiP experiment, or by improved EDM experiment...

  18. The Diffeomorphism Constraint Operator in Loop Quantum Gravity

    CERN Document Server

    Laddha, Alok

    2011-01-01

    We construct the smeared diffeomorphism constraint operator at finite triangulation from the basic holonomy- flux operators of Loop Quantum Gravity, evaluate its continuum limit on the Lewandowski- Marolf habitat and show that the action of the continuum operator provides an anomaly free representation of the Lie algebra of diffeomorphisms of the 3- manifold. Key features of our analysis include: (i) finite triangulation approximants to the curvature, $F_{ab}^i$ of the Ashtekar- Barbero connection which involve not only small loop holonomies but also small surface fluxes as well as an explicit dependence on the edge labels of the spin network being acted on (ii) the dependence of the small loop underlying the holonomy on both the direction and magnitude of the shift vector field (iii) continuum constraint operators which do {\\em not} have finite action on the kinematic Hilbert space, thus implementing a key lesson from recent studies of parameterised field theory by the authors. Features (i) and (ii) provide ...

  19. Constraints on the optical depth of galaxy groups and clusters

    CERN Document Server

    Flender, Samuel; McDonald, Michael

    2016-01-01

    Future data from galaxy redshift surveys, combined with high-resolutions maps of the cosmic microwave background, will enable measurements of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) signal with unprecedented statistical significance. This signal probes the matter-velocity correlation function, scaled by the average optical depth ($\\tau$) of the galaxy groups and clusters in the sample, and is thus of fundamental importance for cosmology. However, in order to translate pairwise kSZ measurements into cosmological constraints, external constraints on $\\tau$ are necessary. In this work, we present a new model for the intra-cluster medium, which takes into account star-formation, feedback, non-thermal pressure, and gas cooling. Our semi-analytic model is computationally efficient and can reproduce results of recent hydrodynamical simulations of galaxy cluster formation. By calibrating the model using recent X-ray measurements of gas density profiles of clusters and $M_{\\mathrm{gas}}-M$ relations of groups ...

  20. Lower limb kinematic variability in dancers performing drop landings onto floor surfaces with varied mechanical properties.

    Science.gov (United States)

    Reeve, Helen K; Hopper, Luke S; Elliott, Bruce C; Ackland, Timothy R

    2013-08-01

    Elite dancers perform highly skilled and consistent movements. These movements require effective regulation of the intrinsic and extrinsic forces acting within and on the body. Customized, compliant floors typically used in dance are assumed to enhance dance performance and reduce injury risk by dampening ground reaction forces during tasks such as landings. As floor compliance can affect the extrinsic forces applied to the body, secondary effects of floor properties may be observed in the movement consistency or kinematic variability exhibited during dance performance. The aim of this study was to investigate the effects of floor mechanical properties on lower extremity kinematic variability in dancers performing landing tasks. A vector coding technique was used to analyze sagittal plane knee and ankle joint kinematic variability, in a cohort of 12 pre-professional dancers, through discrete phases of drop landings from a height of 0.2m. No effect on kinematic variability was observed between floors, indicating that dancers could accommodate the changing extrinsic floor conditions. Future research may consider repeat analysis under more dynamic task constraints with a less experienced cohort. However, knee/ankle joint kinematic variability was observed to increase late in the landing phase which was predominantly comprised of knee flexion coupled with the terminal range of ankle dorsiflexion. These findings may be the result of greater neural input late in the landing phase as opposed to the suggested passive mechanical interaction of the foot and ankle complex at initial contact with a floor. Analysis of joint coordination in discrete movement phases may be of benefit in identifying intrinsic sources of variability in dynamic tasks that involve multiple movement phases.

  1. Ionized gas kinematics of galaxies in the CALIFA survey I: Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

    CERN Document Server

    Garcia-Lorenzo, B; Barrera-Ballesteros, J K; Masegosa, J; Husemann, B; Falcón-Barroso, J; Lyubenova, M; Sanchez, S F; Walcher, J; Mast, D; Garcia-Benito, R; Mendez-Abreu, J; van de Ven, G; Spekkens, K; Holmes, L; Monreal-Ibero, A; del Olmo, A; Ziegler, B; Bland-Hawthorn, J; Sanchez-Blazquez, P; Iglesias-Paramo, J; Aguerri, J A L; Papaderos, P; Gomes, J M; Marino, R A; Delgado, R M Gonzalez; Cortijo-Ferrero, C; Lopez-Sanchez, A R; Bekeraite, S; Wisotzki, L; Bomans, D

    2014-01-01

    This work provides an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of this survey for including kinematical criteria for specific studies. From the first 200 galaxies observed by CALIFA, we present the 2D kinematic view of the 177 galaxies satisfying a gas detection threshold. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component. The main kinematic parameters were directly derived from the radial velocities with no assumptions on the internal motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [OIII] profiles. Most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. 35% of the objects present evidence of a displacemen...

  2. Parallel Handling of Integrity Constraints

    NARCIS (Netherlands)

    Grefen, P.W.P.J.; Flokstra, Jan; Apers, Peter M.G.

    1990-01-01

    Integrity constraints form an important part of a data model. Therefore, a complete integrity constraint handling subsystem is considered an important part of any modern DBMS. In implementing an integrity constraint handling subsystem, there are two major problem areas: providing enough functionalit

  3. Kinematics and Dynamics of a Translational Parallel Robot Based on Planar Mechanisms

    Directory of Open Access Journals (Sweden)

    Mario A. Garcia-Murillo

    2016-11-01

    Full Text Available In this contribution, a novel translational parallel robot composed of an arrangement of mechanisms with planar motion is presented. Its mobility is analyzed and the position analysis is solved by using equations derived from mechanical constraints. Furthermore, the analysis of velocity and acceleration are solved by means of the screw theory. For completeness, the inverse dynamics are also presented and solved by means of an interesting combination of the screw theory and the virtual work principle. Finally, a numerical example is included to show the application of the kinematic model, which is verified with the aid of a commercially available software.

  4. kinematics of nearby galaxies using Fabry-Perot and IFU data

    Science.gov (United States)

    Erroz-Ferrer, Santiago; S4G Team; MUSE-GTO Consortium

    2017-03-01

    I present here analysis of the shapes of the rotation curves of a large sample of nearby spiral galaxies with high angular and spectral resolution Hα (Fabry-Perot GHαFaS) kinematics, and the resulting constraints on their total mass distributions. In particular I discuss how their rotation curve shapes relate to key galaxy properties. Finally I present related results from the MUSE Atlas of Disks (MAD) program, which is dissecting the nearby disk population with IFU spectroscopy at ~100pc resolution.

  5. The complexity of South China Sea kinematics

    Science.gov (United States)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  6. The kinematics of machinery outlines of a theory of machines

    CERN Document Server

    Reuleaux, Franz

    2012-01-01

    A classic on the kinematics of machinery, this volume was written by the Father of Kinematics. Reuleaux writes with authority and precision, developing the subject from its fundamentals. 450 figures. 1876 edition.

  7. Action experience changes attention to kinematic cues

    Directory of Open Access Journals (Sweden)

    Courtney eFilippi

    2016-02-01

    Full Text Available The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-month-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue or did not match the orientation of the rod (incongruent cue. To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first x 2 (congruent kinematic cue vs. incongruent kinematic cue between-subjects design. We show that 13-month-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics.

  8. KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Courtney; Dickey, John M. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart 7000 (Australia)

    2012-07-01

    Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.

  9. Kinematic artifacts in prestack depth migration.

    NARCIS (Netherlands)

    Stolk, C.C.; Symes, W.W.

    2004-01-01

    Strong refraction of waves in the migration velocity model introduces kinematic artifacts¿coherent events not corresponding to actual reflectors¿into the image volumes produced by prestack depth migration applied to individual data bins. Because individual bins are migrated independently, the migrat

  10. KINEMATICS OF 13 BRIGHTEST CLUSTER GALAXIES

    NARCIS (Netherlands)

    FISHER, D; ILLINGWORTH, G; FRANX, M

    1995-01-01

    Velocity dispersion profiles and rotation curves have been determined for a sample of 13 brightest duster galaxies (BCGs) in order to study their internal stellar kinematics and investigate their relationship to ellipticals. We find that BCGs generally display velocity dispersion profiles with gradi

  11. Kinematic structures in galactic disc simulations

    NARCIS (Netherlands)

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.

    2011-01-01

    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic structure

  12. Kinematics of shot-geophone migration

    NARCIS (Netherlands)

    C.C. Stolk; M.V. de Hoop; W.W. Symes

    2009-01-01

    Recent analysis and synthetic examples have shown that many prestack depth migration methods produce nonflat image gathers containing spurious events, even when provided with a kinematically correct migration velocity field, if this velocity field is highly refractive. This pathology occurs in all m

  13. Constrained tri-sphere kinematic positioning system

    Science.gov (United States)

    Viola, Robert J

    2010-12-14

    A scalable and adaptable, six-degree-of-freedom, kinematic positioning system is described. The system can position objects supported on top of, or suspended from, jacks comprising constrained joints. The system is compatible with extreme low temperature or high vacuum environments. When constant adjustment is not required a removable motor unit is available.

  14. Unitary Gas Constraints on Nuclear Symmetry Energy

    CERN Document Server

    Kolomeitsev, Evgeni E; Ohnishi, Akira; Tews, Ingo

    2016-01-01

    We show the existence of a lower bound on the volume symmetry energy parameter $S_0$ from unitary gas considerations. We further demonstrate that values of $S_0$ above this minimum imply upper and lower bounds on the symmetry energy parameter $L$ describing its lowest-order density dependence. The bounds are found to be consistent with both recent calculations of the energies of pure neutron matter and constraints from nuclear experiments. These results are significant because many equations of state in active use for simulations of nuclear structure, heavy ion collisions, supernovae, neutron star mergers, and neutron star structure violate these constraints.

  15. Loop theory and applications to some key problems of kinematic structure of kinematic chains

    Institute of Scientific and Technical Information of China (English)

    Huafeng DING; Zhen HUANG

    2009-01-01

    Structure synthesis of mechanisms is a pivotal issue in the field of mechanical innovation and mechanical conceptual design. In this paper, a new loop theory of kinematic chains is proposed. Based on this theory, some key problems that hamper computer-based automatic synthesis of mechanisms are solved. 1) The open problem of isomorphism of kinematic chains that has lasted for more than four decades is successfully solved. 2) A new rigid sub-chain detection method that is especially suitable for complex chains is proposed. 3) The characteristic representation code remains the same even if the drawing modes and labeling ways of a chain are changed, and an atlas database of kinematic chains is established. The multi-value problem for the representation of kinematic chains is solved. The results in this paper will benefit the digitization and computerization of mechanical conceptual design.

  16. Collinear cluster tri-partition: Kinematics constraints and stability of collinearity

    Science.gov (United States)

    Holmvall, P.; Köster, U.; Heinz, A.; Nilsson, T.

    2017-01-01

    Background: A new mode of nuclear fission has been proposed by the FOBOS Collaboration, called collinear cluster tri-partition (CCT), and suggests that three heavy fission fragments can be emitted perfectly collinearly in low-energy fission. This claim is based on indirect observations via missing-energy events using the 2 v 2 E method. This proposed CCT seems to be an extraordinary new aspect of nuclear fission. It is surprising that CCT escaped observation for so long given the relatively high reported yield of roughly 0.5 % relative to binary fission. These claims call for an independent verification with a different experimental technique. Purpose: Verification experiments based on direct observation of CCT fragments with fission-fragment spectrometers require guidance with respect to the allowed kinetic-energy range, which we present in this paper. Furthermore, we discuss corresponding model calculations which, if CCT is found in such verification experiments, could indicate how the breakups proceed. Since CCT refers to collinear emission, we also study the intrinsic stability of collinearity. Methods: Three different decay models are used that together span the timescales of three-body fission. These models are used to calculate the possible kinetic-energy ranges of CCT fragments by varying fragment mass splits, excitation energies, neutron multiplicities, and scission-point configurations. Calculations are presented for the systems 235U(nth,f ) and 252Cf(s f ) , and the fission fragments previously reported for CCT; namely, isotopes of the elements Ni, Si, Ca, and Sn. In addition, we use semiclassical trajectory calculations with a Monte Carlo method to study the intrinsic stability of collinearity. Results: CCT has a high net Q value but, in a sequential decay, the intermediate steps are energetically and geometrically unfavorable or even forbidden. Moreover, perfect collinearity is extremely unstable, and broken by the slightest perturbation. Conclusions: According to our results, the central fragment would be very difficult to detect due to its low kinetic energy, raising the question of why other 2 v 2 E experiments could not detect a missing-mass signature corresponding to CCT. Considering the high kinetic energies of the outer fragments reported in our study, direct-observation experiments should be able to observe CCT. Furthermore, we find that a realization of CCT would require an unphysical fine tuning of the initial conditions. Finally, our stability calculations indicate that, due to the pronounced instability of the collinear configuration, a prolate scission configuration does not necessarily lead to collinear emission, nor does equatorial emission necessarily imply an oblate scission configuration. In conclusion, our results enable independent experimental verification and encourage further critical theoretical studies of CCT.

  17. Kinematic Constraints on Evolutionary Scenarios for Blue Compact Dwarf Galaxies I. Neutral Gas Dynamics

    CERN Document Server

    Van Zee, L; Skillman, E D; Zee, Liese van; Salzer, John J.; Skillman, Evan D.

    2001-01-01

    We present the results of high spatial resolution HI synthesis observations of six blue compact dwarf (BCD) galaxies. Optically, the selected galaxies have smooth, symmetric isophotes, and thus are the most likely of the BCD class to fade into an object morphologically similar to a dwarf elliptical when the current starburst ends. The neutral gas in all six galaxies appears to be rotationally supported, however, indicating that true morphological transformation from a BCD to a dE will require significant loss of angular momentum. Based on the observed neutral gas dynamics of these and other BCDs, it is unlikely that present-day BCDs will evolve directly into dwarf ellipticals after a starburst phase. We discuss alternative evolutionary scenarios for BCDs and place them within the larger context of galaxy formation and evolution models.

  18. Collective behaviour of self-propelling particles with conservative kinematic constraints

    NARCIS (Netherlands)

    Ratushna, Valeriya Igorivna

    2007-01-01

    In this thesis I considered the dynamics of self-propelling particles (SPP). Flocking of living organisms like birds, fishes, ants, bacteria etc. is an area where the theory of the collective behaviour of SPP can be applied. One can often see how these animals develop coherent motion, amazing the ob

  19. Collective behaviour of self-propelling particles with conservative kinematic constraints

    NARCIS (Netherlands)

    Ratushna, Valeriya Igorivna

    2007-01-01

    In this thesis I considered the dynamics of self-propelling particles (SPP). Flocking of living organisms like birds, fishes, ants, bacteria etc. is an area where the theory of the collective behaviour of SPP can be applied. One can often see how these animals develop coherent motion, amazing the

  20. A New Topological Description Method of Kinematic Chain

    Institute of Scientific and Technical Information of China (English)

    Ding Huafeng; Huang Zhen; Cao Yi

    2004-01-01

    This paper presents a novel method for the description of kinematic chains, namely the canonical description of kinematic chains including the synthetic degree-sequences and the canonical adjacency matrices sets of kinematic chains. The most important characteristic of this new description method is its uniqueness. Based on the new principle the isomorphism identification becomes easy and the structures of all kinds of kinematic chains can be stored in computer for the benefits of the realization of automation and intelligence of machine design.