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Sample records for quasiclassical trajectory study

  1. Direct dynamics trajectory study of the reaction of formaldehyde cation with D2: vibrational and zero-point energy effects on quasiclassical trajectories.

    Science.gov (United States)

    Liu, Jianbo; Song, Kihyung; Hase, William L; Anderson, Scott L

    2005-12-22

    Quasiclassical, direct dynamics trajectories have been used to study the reaction of formaldehyde cation with molecular hydrogen, simulating the conditions in an experimental study of H2CO+ vibrational effects on this reaction. Effects of five different H2CO+ modes were probed, and we also examined different approaches to treating zero-point energy in quasiclassical trajectories. The calculated absolute cross-sections are in excellent agreement with experiments, and the results provide insight into the reaction mechanism, product scattering behavior, and energy disposal, and how they vary with impact parameter and reactant state. The reaction is sharply orientation-dependent, even at high collision energies, and both trajectories and experiment find that H2CO+ vibration inhibits reaction. On the other hand, the trajectories do not reproduce the anomalously strong effect of nu2(+) (the CO stretch). The origin of the discrepancy and approaches for minimizing such problems in quasiclassical trajectories are discussed.

  2. Quasiclassical trajectory study of fast H-atom collisions with acetylene.

    Science.gov (United States)

    Han, Yong-Chang; Sharma, Amit R; Bowman, Joel M

    2012-06-07

    Translationally hot H collisions with the acetylene are investigated using quasiclassical trajectory calculations, on a recent full-dimensional ab initio-based potential energy surface. Three outcomes are focused on: non-reactive energy transfer via prompt collisions, non-reactive energy transfer via the formation of the vinyl complex, and reactive chemical H-atom exchange, also via complex formation. The details of these outcomes are presented and correlated with the collision lifetime. Large energy transfer is found via complex formation, which can subsequently decay back to reactants, a non-reactive event, or to new products, a reactive event. For the present system, these two events are experimentally indistinguishable.

  3. Quasiclassical trajectory study of collisional energy transfer in toluene systems. I. Argon bath gas: Energy dependence and isotope effects

    Science.gov (United States)

    Lim, Kieran F.

    1994-05-01

    Experimental studies of collisional energy transfer from highly vibrationally excited toluene to various bath gases have recently been reported [Toselli and Barker, J. Chem. Phys. 97, 1809 (1992), and references therein]. A quasiclassical trajectory investigation for toluene in argon bath gas at 300 K for initial internal energies E'=41 000, 30 000, and 15 000 cm-1 is reported here. Collisional energy transfer is almost linearly dependent on E'. Predictions of energy transfer quantities are very sensitive to the average well depth of the assumed individual pairwise potentials, but is less sensitive to the detailed shape. Qualitative and quantitative agreement with experiment is obtained where the overall well depth is physically realistic. Isotope studies using 40Ar and pseudohelium (4Ar) bath gases indicate that energy transfer is independent of the mass of the bath-gas collider, but perdeuteration increases 1/2 by 13% over the undeuterated values.

  4. Quasiclassical trajectory study on the integral cross-section and stereodynamics information of the reaction O(1D) + H2(v = 0, j = 0) → OH + H

    Indian Academy of Sciences (India)

    Tianyun Chen; Ningjiu Zhao; Weiping Zhang; Dongjun Wang; Xinqiang Wang

    2011-05-01

    Integral cross-section and stereodynamics study of the reaction O(1D)+H2( = 0, = 0) → OH + H is undertaken using the quasiclassical trajectory (QCT) method for the collision energy is in the large length of 1.3 to 43 kcal/mol using Dobbyn and Knowles (DK) surface, and the obtained results are compared with those available from earlier available calculated results on the BR surface. The integral cross sections obtained from the quasiclassical trajectory method are in good agreement with those of Chebyshev wave packet method for collision energies above 0.2 eV.We also investigated the vector correlations and polarized dependent differential cross sections (PDDCS) at different collision energies. It is demonstrated that the alignment and state distribution significantly decrease with increase in the collision energy.

  5. Study of the H+HS reaction on a newly built potential energy surface using the quasi-classical trajectory method

    Institute of Scientific and Technical Information of China (English)

    Bai Meng-Meng; Ge Mei-Hua; Yang Huan; Zheng Yu-Jun

    2012-01-01

    The quasi-classical trajectory (QCT) method is used to study the H+HS reaction on a newly built potential energy surface (PES) of the triplet state of H2S (3A") in a collision energy range of 0-60 kcal/mol.Both scalar properties,such as the reaction probability and the integral cross section (ICS),and the vector properties,such as the angular distribution between the relative velocity vector of the reactant and that of the product,etc.,are investigated using the QCT method.It is found that the ICSs obtained by the QCT method and the quantum mechanical (QM) method accord well with each other.In addition,the distribution for the product vibrational states is cold,while that for the product rotational states is hot for both reaction channels in the whole energy range studied here.

  6. Study of the H+HS reaction on a newly built potential energy surface using the quasi-classical trajectory method

    Science.gov (United States)

    Bai, Meng-Meng; Ge, Mei-Hua; Yang, Huan; Zheng, Yu-Jun

    2012-12-01

    The quasi-classical trajectory (QCT) method is used to study the H+HS reaction on a newly built potential energy surface (PES) of the triplet state of H2S (3A″) in a collision energy range of 0-60 kcal/mol. Both scalar properties, such as the reaction probability and the integral cross section (ICS), and the vector properties, such as the angular distribution between the relative velocity vector of the reactant and that of the product, etc., are investigated using the QCT method. It is found that the ICSs obtained by the QCT method and the quantum mechanical (QM) method accord well with each other. In addition, the distribution for the product vibrational states is cold, while that for the product rotational states is hot for both reaction channels in the whole energy range studied here.

  7. Quasi-classical trajectory study of the reaction N(4S) + H2 and its reverse reaction: Role of initial vibrational and rotational excitations in chemical stereodynamics

    Indian Academy of Sciences (India)

    Juan Zhang; Shunle Dong

    2013-07-01

    To investigate the effects of reagent vibrational and rotational states on the stereodynamical properties of the N(4S) + H2(, )→NH + H reaction and its reverse reaction of H(2S) + NH(, )→N(4S) + H2, we reported a detailed quasiclassical trajectory study using the 4A" double many-body expansion potential energy surface and at the collision energy of 35 kcal/mol. The density distribution of (r) as a function of the angle between and ', and that of (r) as a function of the dihedral angle between the plane containing -' and the plane containing '- ', the normal differential cross-sections as well as the averaged product rotational alignment parameter 〈 2('.) 〉 are calculated and reported. Comparison between the two reactions has showed that the degrees of alignment and orientation of products related to reagent rovibrational state have marked differences for the two reactive systems.

  8. Quasiclassical Trajectory Study of Collisional Energy Transfer between Highly Excited C6F6 and N2 ,O2 and Ground State C6F6

    Institute of Scientific and Technical Information of China (English)

    Jian Hua ZHOU; Shao Kun WANG; Zhi Jun YU; Hai Hui JIANG; Yue Shu GU

    2003-01-01

    Quasiclassical trajectory calculation (QCT) is used frequently for studying collisional energy transfer between highly vibrationally excited molecules and bath gases. In this paper, the QCT of the energy transfer between highly vibrationally excited C6F6 and N2 ,O2 and ground state C6F6 were performed. The results indicate that highly vibrationally excited C6F6 transferred vibrational energy to vibrational distribution of N2, O2 and ground state C6F6, so they are V-V energy transfer. Especially it is mainly V-V resonance energy transfer between excited C6F6 and ground state C6F6, excited C6F6 transfers more vibrational energy to ground state C6F6 than to N2 and O2 . The values of QCT , -〈△Evib〉of excited C6F6 are smaller than those of experiments.

  9. Quasi-classical trajectory study of the reaction H' + HS on a new ab initio potential energy surface H2S (3A")

    Indian Academy of Sciences (India)

    Jinghan Zou; Shuhui Yin; Dan Wu; Mingxing Guo; Xuesong Xu; Hong Gao; Lei Li; Li Che

    2013-09-01

    Theoretical study on the dynamics of reactions H' + HS( = 0, = 0)→H2 + S and H' + HS( =0, = 0)→ H + H'S is performed with quasi-classical trajectory (QCT) method on a new ab initio potential energy surface for the lowest triplet state of H2S (3A") constructed in 2012 by Lv et al. The QCT-calculated reaction integral cross-sections are in good agreement with previous quantum wave packet results over the collision energy range of 0-50 kcal/mol. Both the abstraction and exchange reactions are governed by direct reaction dynamics and the trajectories follow the minimum energy path. The rotational angular momentum vector ' of products in the two reaction channels are not only aligned perpendicular to scattering plane but also oriented along the negative direction of the axis perpendicular to the scattering plane. With the increase in collision energy, the variation trends of product polarization in the two reaction channels are different and that may be attributed to the obviously different characteristic of the two channels on the potential energy surface.

  10. Study on local mode vibrations of molecular vibrational excitation states in CH4,SiH4 and GeH4 with quasiclassical trajectory method

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 李慎敏; 唐敖庆

    1995-01-01

    By using the quasiclassical trajectory method,changes of normal and local mode vibrationalexcitation energies with time are investigated for XH4 (X=C,Si,Ge) molecules.The results demonstrate thatin a CH4 molecule the coupling between C—H stretching vibration and H—C—H bending vibration is relative-ly large so that the energy transfer is fast;while in SiH4 or GeH4 molecules this coupling is relativelysmall and thus an obvious energy relaxation is observed.This implies that there exists approximate local modevibrations for certain vibrational excitation states.

  11. Quasiclassical trajectory studies of 18O(3P) + NO2 isotope exchange and reaction to O2 + NO on D0 and D1 potentials

    Science.gov (United States)

    Fu, Bina; Zhang, Dong H.; Bowman, Joel M.

    2013-07-01

    We report quasiclassical trajectory calculations for the bimolecular reaction 18O(3P) + NO2 on the recent potential energy surfaces of the ground (D0) and first excited (D1) states of NO3 [B. Fu, J. M. Bowman, H. Xiao, S. Maeda, and K. Morokuma, J. Chem. Theory. Comput. 9, 893 (2013)], 10.1021/ct3009792. The branching ratio of isotope exchange versus O2 + NO formation, as well as the product angular distributions and energy and rovibrational state distributions are presented. The calculations are done at the collision energy of relevance to recent crossed beam experiments [K. A. Mar, A. L. Van Wyngarden, C.-W. Liang, Y. T. Lee, J. J. Lin, and K. A. Boering, J. Chem. Phys. 137, 044302 (2012)], 10.1063/1.4736567. Very good agreement is achieved between the current calculations and these experiments for the branching ratio and final translational energy and angular distributions of isotope exchange products 16O(3P) + NO2 and O2 + NO formation products. The reactant 18O atom results in 18O16O but not N18O for the O2 + NO formation product channel, consistent with the experiment. In addition, the detailed vibrational and rotational state information of diatomic molecules calculated currently for the 34O2 + NO formation channel on D0 and D1 states are in qualitative agreement with the previous experimental and theoretical results of the photodissociation of NO3 and are consistent with older thermal bimolecular kinetics measurements.

  12. Quasiclassical trajectory study of collisional energy transfer in toluene systems. II. Helium bath gas: Energy and temperature dependences, and angular momentum transfer

    Science.gov (United States)

    Lim, Kieran F.

    1994-11-01

    The collisional deactivation of highly vibrationally excited toluene-d0 and toluene-d8 by helium bath gas has been investigated using quasiclassical trajectory simulations. Collisional energy transfer was found to increase with initial toluene internal energy, in agreement with the experiments of Toselli and Barker [J. Chem. Phys. 97, 1809 (1992), and references therein]. The temperature dependence of 1/2 is predicted to be T(0.44±0.10), in agreement with the experiments of Heymann, Hippler, and Troe [J. Chem. Phys. 80, 1853 (1984)]. Toluene is found to have no net angular-momentum (rotational-energy) transfer to helium bath gas, although 1/2 has a temperature dependence of T(0.31±0.07). Re-evaluation of earlier calculations [``Paper I:'' Lim, J. Chem. Phys. 100, 7385 (1994)] found that rotational energy transfer could be induced by increasing the mass of the collider, or by increasing the strength of the intermolecular interaction: in these cases, angular-momentum transfer depended on the initial excitation energy. In all cases, the final rotational distributions remained Boltzmann.

  13. Zero-point energy constraint in quasi-classical trajectory calculations.

    Science.gov (United States)

    Xie, Zhen; Bowman, Joel M

    2006-04-27

    A method to constrain the zero-point energy in quasi-classical trajectory calculations is proposed and applied to the Henon-Heiles system. The main idea of this method is to smoothly eliminate the coupling terms in the Hamiltonian as the energy of any mode falls below a specified value.

  14. Oscillatory reaction cross sections caused by normal mode sampling in quasiclassical trajectory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Tibor; Vikár, Anna; Lendvay, György, E-mail: lendvay.gyorgy@ttk.mta.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2., H-1117 Budapest (Hungary)

    2016-01-07

    The quasiclassical trajectory (QCT) method is an efficient and important tool for studying the dynamics of bimolecular reactions. In this method, the motion of the atoms is simulated classically, and the only quantum effect considered is that the initial vibrational states of reactant molecules are semiclassically quantized. A sensible expectation is that the initial ensemble of classical molecular states generated this way should be stationary, similarly to the quantum state it is supposed to represent. The most widely used method for sampling the vibrational phase space of polyatomic molecules is based on the normal mode approximation. In the present work, it is demonstrated that normal mode sampling provides a nonstationary ensemble even for a simple molecule like methane, because real potential energy surfaces are anharmonic in the reactant domain. The consequences were investigated for reaction CH{sub 4} + H → CH{sub 3} + H{sub 2} and its various isotopologs and were found to be dramatic. Reaction probabilities and cross sections obtained from QCT calculations oscillate periodically as a function of the initial distance of the colliding partners and the excitation functions are erratic. The reason is that in the nonstationary ensemble of initial states, the mean bond length of the breaking C–H bond oscillates in time with the frequency of the symmetric stretch mode. We propose a simple method, one-period averaging, in which reactivity parameters are calculated by averaging over an entire period of the mean C–H bond length oscillation, which removes the observed artifacts and provides the physically most reasonable reaction probabilities and cross sections when the initial conditions for QCT calculations are generated by normal mode sampling.

  15. Quantum wave packet and quasiclassical trajectory studies of the reaction H(2S) + CH(X2 Π; v = 0, j = 1) → C(1D) + H2 (X1 Σg+): Coriolis coupling effects and stereodynamics.

    Science.gov (United States)

    Lu, Ruifeng; Wang, Yunhui; Deng, Kaiming

    2013-07-30

    The quantum mechanics (QM) and quasiclassical trajectory (QCT) calculations have been carried out for the title reaction with the ground minimal allowed rotational state of CH (j = 1) on the 1 (1)A' potential energy surface. For the reaction probability at total angular momentum J = 0, a similar trend of the QM and QCT calculations is observed, and the QM results are larger than the latter almost in the whole considered energy range (0.1-1.5 eV). The QCT integral cross sections are larger than the QM results with centrifugal sudden approximation, while smaller than those from QM method including Coriolis coupling for collision energies bigger than 0.25 eV. The quantum wave-packet computations show that the Coriolis coupling effects get more and more pronounced with increasing of J. In addition to the scalar properties, the stereodynamical properties, such as the average rotational alignment factor , the angular distributions P(θr ), P(ϕr ), P(θr ,ϕr ), and the polarization-dependent generalized differential cross sections have been explored in detail by QCT approach.

  16. Time-dependent quantum wave packet and quasiclassical trajectory studies of the Au(2S) + H2(X1∑+g) → AuH(X1∑+g) + H(2S) reaction

    Science.gov (United States)

    Yuan, Jiuchuang; Cheng, Dahai; Sun, Zhigang; Chen, Maodu

    2014-11-01

    The time-dependent quantum wave packet (TDWP) and quasiclassical trajectory calculations (QCT) are carried out for the Au(2S) + H2(X1∑+g) → AuH(X1∑+g) + H(2S) reaction on a global potential energy surface. The reaction probabilities at a series of J values, integral cross sections (ICSs) and differential cross sections of the title reaction are calculated by the TDWP method. For reaction probabilities, there are a mass of sharp oscillations at low collision energy, which can be attributed to resonances supported by the potential well. Due to the endothermicity of the title reaction, the total ICS shows a threshold about 1.53 eV. In order to further investigate the reactive mechanism, the lifetime of complex is calculated by QCT method. At the low collision energy, most intermediate complexes are long lived, which implies that the reaction is governed by indirect reactive mechanism. With the collision energy increasing, the direct reactive mechanism occupies the dominant position. Due to the change of the reactive mechanism, the angular distribution shifts toward the forward direction with collision energy increasing. The isotopic variant, Au + D2→AuD + D reaction, is also calculated by TDWP method. The calculated reaction probabilities and ICSs show that the isotope effect reduces the reactivity.

  17. Quasiclassical trajectory and wave packet calculations for D + CaCl(X2Σ+; vi = 0, ji = 0) → DCl + Ca(1S) reaction

    Science.gov (United States)

    Tan, Rui Shan; Yan, Wei; Lin, Shi Ying

    2017-01-01

    A computational study for the title reaction is carried out employing recent ab initio potential energy surface. J = 0 reaction probability is obtained using both quasiclassical trajectory (QCT) and wave packet methods. The total and state resolved integral as well as differential cross sections are also obtained by means of QCT method. Dynamics of the title reaction shows qualitative similarity with its isotopic counterpart, the H + CaCl reaction, but quantitatively, reactivity is significantly enhanced in the title reaction. In addition, the effect of initial rotational state excitation on H + CaCl reaction is investigated.

  18. A quasiclassical trajectory analysis of stereodynamics of the H+FCl (=0-3, =0-3) → HCl+F reaction

    Indian Academy of Sciences (India)

    Xian-Fang Yue; Xiangyang Miao

    2011-01-01

    The chemical stereodynamics for the title reaction are studied by the quasiclassical trajectory method. Employing the recent works of Deskevich, Hayes, Takahashi, Skodje, and Nesbitt (DHTSN) potential energy surface of the ground 12A' electronic state, the present work calculates the polarizationdependent differential cross sections and the three angular distributions which describe the vector correlations among the product angular momentum j' and the reagent and the product initial relative velocities k and k'. The effect of vibrational and rotational excitations for the reagent FCl and the influence of collision energies on the stereodynamical quantities are also investigated and discussed.

  19. An improved potential energy surface and multi-temperature quasiclassical trajectory calculations of N2 + N2 dissociation reactions.

    Science.gov (United States)

    Bender, Jason D; Valentini, Paolo; Nompelis, Ioannis; Paukku, Yuliya; Varga, Zoltan; Truhlar, Donald G; Schwartzentruber, Thomas; Candler, Graham V

    2015-08-01

    Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration of collision-induced dissociation of molecular species and energy transfer between the translational and internal modes of the gas molecules. Here, we describe a study of the N2 + N2⟶N2 + 2N and N2 + N2⟶4N nitrogen dissociation reactions using the quasiclassical trajectory (QCT) method. The simulations used a new potential energy surface for the N4 system; the surface is an improved version of one that was presented previously. In the QCT calculations, initial conditions were determined based on a two-temperature model that approximately separates the translational-rotational temperature from the vibrational temperature of the N2 diatoms. Five values from 8000 K to 30,000 K were considered for each of the two temperatures. Over 2.4 × 10(9) trajectories were calculated. We present results for ensemble-averaged dissociation rate constants as functions of the translational-rotational temperature T and the vibrational temperature T(v). The rate constant depends more strongly on T when T(v) is low, and it depends more strongly on T(v) when T is low. Quasibound reactant states contribute significantly to the rate constants, as do exchange processes at higher temperatures. We discuss two sets of runs in detail: an equilibrium test set in which T = T(v) and a nonequilibrium test set in which T(v) test set, high-v and moderately-low-j molecules contribute most significantly to the overall dissociation rate, and this state specificity becomes stronger as the temperature decreases. Dissociating trajectories tend to result in a major loss of vibrational energy and a minor loss of rotational energy. In the nonequilibrium test set, as T(v) decreases while T is fixed, higher-j molecules contribute more significantly to the dissociation rate, dissociating trajectories tend to result in a greater rotational energy loss, and the dissociation probability's dependence on v weakens. In

  20. An improved potential energy surface and multi-temperature quasiclassical trajectory calculations of N2 + N2 dissociation reactions

    Science.gov (United States)

    Bender, Jason D.; Valentini, Paolo; Nompelis, Ioannis; Paukku, Yuliya; Varga, Zoltan; Truhlar, Donald G.; Schwartzentruber, Thomas; Candler, Graham V.

    2015-08-01

    Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration of collision-induced dissociation of molecular species and energy transfer between the translational and internal modes of the gas molecules. Here, we describe a study of the N2 + N2⟶N2 + 2N and N2 + N2⟶4N nitrogen dissociation reactions using the quasiclassical trajectory (QCT) method. The simulations used a new potential energy surface for the N4 system; the surface is an improved version of one that was presented previously. In the QCT calculations, initial conditions were determined based on a two-temperature model that approximately separates the translational-rotational temperature from the vibrational temperature of the N2 diatoms. Five values from 8000 K to 30 000 K were considered for each of the two temperatures. Over 2.4 × 109 trajectories were calculated. We present results for ensemble-averaged dissociation rate constants as functions of the translational-rotational temperature T and the vibrational temperature Tv. The rate constant depends more strongly on T when Tv is low, and it depends more strongly on Tv when T is low. Quasibound reactant states contribute significantly to the rate constants, as do exchange processes at higher temperatures. We discuss two sets of runs in detail: an equilibrium test set in which T = Tv and a nonequilibrium test set in which Tv rate, and this state specificity becomes stronger as the temperature decreases. Dissociating trajectories tend to result in a major loss of vibrational energy and a minor loss of rotational energy. In the nonequilibrium test set, as Tv decreases while T is fixed, higher-j molecules contribute more significantly to the dissociation rate, dissociating trajectories tend to result in a greater rotational energy loss, and the dissociation probability's dependence on v weakens. In this way, as Tv decreases, rotational energy appears to compensate for the decline in average vibrational energy in

  1. Quasiclassical trajectory study of the effect of antisymmetric stretch mode excitation on the O({sup 3}P) + CH{sub 4}(ν{sub 3} = 1) → OH + CH{sub 3} reaction on an analytical potential energy surface. Comparison with experiment

    Energy Technology Data Exchange (ETDEWEB)

    Monge-Palacios, M.; González-Lavado, E.; Espinosa-Garcia, J., E-mail: joaquin@unex.es [Departamento de Química Física, Universidad de Extremadura, 06071 Badajoz (Spain)

    2014-09-07

    Motivated by a recent crossed-beam experiment on the title reaction reported by Pan and Liu [J. Chem. Phys. 140, 191101 (2014)], a detailed dynamics study was performed at three collision energies using quasiclassical trajectory (QCT) calculations based on a full-dimensional potential energy surface recently developed by our group (PES-2014). Although theory/experiment agreement is not yet quantitative, in general the theoretical results reproduce the experimental evidence: the vibrational branching ratio of OH(v = 1)/OH(v = 0) is ∼0.8/0.2, excitation of the antisymmetric CH stretching mode in methane increases reactivity by factor 2.28–1.50, although an equivalent amount as translational energy is more efficient in promoting the reaction and, finally, product angular distribution shifts from backward in the CH{sub 4}(ν = 0) ground-state to sideways when the antisymmetric CH stretching mode is excited. These results give confidence to the PES-2014 surface, depend on the quantization procedure used, are comparable with recent QCT calculations or improve previous theoretical studies using a different surface, and demonstrate the utility of the theory/experiment collaboration.

  2. Symmetrical windowing for quantum states in quasi-classical trajectory simulations: Application to electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, Stephen J.; Igumenshchev, Kirill; Miller, William H., E-mail: millerwh@berkeley.edu [Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-08-28

    It has recently been shown [S. J. Cotton and W. H. Miller, J. Chem. Phys. 139, 234112 (2013)] that a symmetrical windowing quasi-classical (SQC) approach [S. J. Cotton and W. H. Miller, J. Phys. Chem. A 117, 7190 (2013)] applied to the Meyer-Miller model [H.-D. Meyer and W. H. Miller, J. Chem. Phys. 70, 3214 (1979)] for the electronic degrees of freedom in electronically non-adiabatic dynamics is capable of quantitatively reproducing quantum mechanical results for a variety of test applications, including cases where “quantum” coherence effects are significant. Here we apply this same SQC methodology, within a flux-side correlation function framework, to calculate thermal rate constants corresponding to several proposed models of electron transfer processes [P. Huo, T. F. Miller III, and D. F. Coker, J. Chem. Phys. 139, 151103 (2013); A. R. Menzeleev, N. Ananth, and T. F. Miller III, J. Chem. Phys. 135, 074106 (2011)]. Good quantitative agreement with Marcus Theory is obtained over several orders of magnitude variation in non-adiabatic coupling. Moreover, the “inverted regime” in thermal rate constants (with increasing bias) known from Marcus Theory is also reproduced with good accuracy by this very simple classical approach. The SQC treatment is also applied to a recent model of photoinduced proton coupled electron transfer [C. Venkataraman, A. V. Soudackov, and S. Hammes-Schiffer, J. Chem. Phys. 131, 154502 (2009)] and population decay of the photoexcited donor state is found to be in reasonable agreement with results calculated via reduced density matrix theory.

  3. Quasi-classical trajectory approach to the stereo-dynamics of the reaction F+HO→HF+O

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Quasi-classical trajectory (QCT) calculations are employed for the reaction F + HO(0,0)→HF + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom F’s relatively strong absorbability to charges on the alignment and the orientation of product molecule HF rotational angular momentum vectors j′ is revealed.

  4. Time-dependent wave packet quantum and quasi-classical trajectory study of He + H₂⁺, D₂⁺ → HeH⁺ + H, HeD⁺ + D reaction on an accurate FCI potential energy surface.

    Science.gov (United States)

    Zhao, Juan; Luo, Yi

    2012-03-15

    The quantum scattering dynamics and quasi-classical trajectory (QCT) calculations have been carried out for the title reaction on an accurate potential energy surface (PES) computed using the full configuration interaction (FCI). On the basis of the PES, the integral cross-sections of He + H₂⁺ (v = 0-3, j = 1) → HeH⁺ + H reaction have been calculated, and the results are generally agreed with the experimental cross-sections obtained by Tang et al. [J. Chem. Phys. 2005, 122, 164301] after taking into account the experimental uncertainties, which proves the reliability of implementing dynamics calculations on the FCI PES. The reaction probability of He + D₂⁺ (v = 0-2, j = 0) → HeD⁺ + D reactions for total angular momentum J = 0 and the integral cross-section (ICS) have been calculated. The significant quantum effect has been explored by the comparison between the QCT reaction probabilities (or ICS) and the quantum mechanical (QM) reaction probabilities (or ICS), which may be attributed to the deep well in the PES of this light atoms system. Furthermore, the role of Coriolis coupling (CC) effects has also been found not important by the comparison between the CC calculation and the centrifugal sudden (CS) approximation calculation, except that the CC total cross-sections for the v = 1 and 2 states show the collision energy-dependent behaviors in the low-energy area, which are different from those based on the CS calculation.

  5. A quasi-classical study of energy transfer in collisions of hyperthermal H atoms with SO2 molecules

    Science.gov (United States)

    da Silva, Ramon S.; Garrido, Juan D.; Ballester, Maikel Y.

    2017-08-01

    A deep understanding of energy transfer processes in molecular collisions is at central attention in physical chemistry. Particularly vibrational excitation of small molecules colliding with hot light atoms, via a metastable complex formation, has shown to be an efficient manner of enhancing reactivity. A quasi-classical trajectory study of translation-to-vibration energy transfer (T-V ET) in collisions of hyperthermal H(2S) atoms with SO2(X˜ 1A') molecules is presented here. For such a study, a double many-body expansion potential energy surface previously reported for HSO2(2A) is used. This work was motivated by recent experiments by Ma et al. studying collisions of H + SO2 at the translational energy of 59 kcal/mol [J. Ma et al., Phys. Rev. A 93, 040702 (2016)]. Calculations reproduce the experimental evidence that during majority of inelastic non-reactive collision processes, there is a metastable intermediate formation (HOSO or HSO2). Nevertheless, the analysis of the trajectories shows that there are two distinct mechanisms in the T-V ET process: direct and indirect. Direct T-V processes are responsible for the high population of SO2 with relatively low vibrational excitation energy, while indirect ones dominate the conversion from translational energy to high values of the vibrational counterpart.

  6. Hermite polynomials and quasi-classical asymptotics

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S. Twareque, E-mail: twareque.ali@concordia.ca [Department of Mathematics and Statistics, Concordia University, Montréal, Québec H3G 1M8 (Canada); Engliš, Miroslav, E-mail: englis@math.cas.cz [Mathematics Institute, Silesian University in Opava, Na Rybníčku 1, 74601 Opava, Czech Republic and Mathematics Institute, Žitná 25, 11567 Prague 1 (Czech Republic)

    2014-04-15

    We study an unorthodox variant of the Berezin-Toeplitz type of quantization scheme, on a reproducing kernel Hilbert space generated by the real Hermite polynomials and work out the associated quasi-classical asymptotics.

  7. Quasiclassical theory of superconductivity: A multiple-interface geometry

    Science.gov (United States)

    Shelankov, A.; Ozana, M.

    2000-03-01

    A method is suggested that allows one to study multiple coherent reflection/transmissions by partially transparent interfaces (e.g., in multilayer mesoscopic structures or grain boundaries in high Tc's), in the framework of the quasiclassical theory of superconductivity. It is argued that in the presence of interfaces, a straight-line trajectory transforms to a simple connected one-dimensional tree (graph) with knots, i.e., the points where the interface scattering events occur and pieces of the trajectories are coupled. For the two-component trajectory ``wave function'' which factorizes the Gor'kov matrix Green's function, a linear boundary condition on the knot is formulated for an arbitrary interface, specular or diffusive (in the many channel model). From the new boundary condition, we derive (i) the excitation scattering amplitude for the multichannel Andreev/ordinary reflection/transmission processes; (ii) the boundary conditions for the Riccati equation; (iii) the transfer matrix which couples the trajectory Green's function before and after the interface scattering. To show the usage of the method, the cases of a film separated from a bulk superconductor by a partially transparent interface, and a SIS' sandwich with finite thickness layers, are considered. The electric current response to the vector potential (the superfluid density ρs) with the π phase difference in S and S' is calculated for the sandwich. It is shown that the model is very sensitive to imperfection of the SS' interface: the low temperature response being paramagnetic (ρs0) when the probability of reflection is as low as a few percent.

  8. Evaluation of Jacobian determinants by Monte Carlo methods - Application to the quasiclassical approximation in molecular scattering.

    Science.gov (United States)

    La Budde, R. A.

    1972-01-01

    Sampling techniques have been used previously to evaluate Jacobian determinants that occur in classical mechanical descriptions of molecular scattering. These determinants also occur in the quasiclassical approximation. A new technique is described which can be used to evaluate Jacobian determinants which occur in either description. This method is expected to be valuable in the study of reactive scattering using the quasiclassical approximation.

  9. A STUDY OF SHUTTLECOCK'S TRAJECTORY IN BADMINTON

    Directory of Open Access Journals (Sweden)

    Yung-Jen Chen

    2009-12-01

    Full Text Available The main purpose of this study was to construct and validate a motion equation for the flight of the badminton and to find the relationship between the air resistance force and a shuttlecock's speed. This research method was based on motion laws of aerodynamics. It applied aerodynamic theories to construct motion equation of a shuttlecock's flying trajectory under the effects of gravitational force and air resistance force. The result showed that the motion equation of a shuttlecock's flight trajectory could be constructed by determining the terminal velocity. The predicted shuttlecock trajectory fitted the measured data fairly well. The results also revealed that the drag force was proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. Finally, this study suggested that we could use a scientific approach to measure a shuttlecock's velocity objectively when testing the quality of shuttlecocks. And could be used to replace the traditional subjective method of the Badminton World Federation based on players' striking shuttlecocks, as well as applying research findings to improve professional knowledge of badminton player training

  10. Searching for resonances in the reaction Cl+CH4-->HCl+CH3: quantum versus quasiclassical dynamics and comparison with experiments.

    Science.gov (United States)

    Martínez, Rodrigo; González, Miguel; Defazio, Paolo; Petrongolo, Carlo

    2007-09-14

    A quantum-mechanical (QM) and quasiclassical trajectory (QCT) study was performed on the title reaction, using a pseudotriatomic ab initio based surface. Probabilities and integral cross sections present some clear peaks versus the collision energy E(col), which we assign to Feshbach resonances of the transition state, where the light H atom oscillates between the heavy Cl and CH(3) groups. For ground-state reactants, reactivity is essentially of quantum origin (QCT observables and oscillations are smaller, or much smaller, than QM ones), and the calculated integral cross section and product distributions are in reasonable agreement with the experiment. The reaction occurs through an abstraction mechanism, following both a direct and an indirect mechanism. The quasiclassical trajectory calculations show the participation of a short-lived collision complex in the microscopic reaction mechanism. Finally, QCT differential cross sections of Cl+CH(4)-->HCl (nu(')=0 and 1)+CH(3) oscillate versus E(col), whereas experimentally this only occurs for HCl (nu(')=1). This theoretical result and other oscillating properties found here could, however, be related to the existence of a Feshbach resonance for the production of HCl (nu(')=1), as suggested by experimentalists.

  11. Quasi-classical alternatives in quantum chemistry

    CERN Document Server

    Gineityte, V

    2014-01-01

    The article contains an overview of authors achievements in development of alternative quantum-chemical approaches oriented towards revival of the classical tradition of qualitative chemical thinking instead of obtaining numerical results. The above-mentioned tradition is concluded to be based mainly on principles (rules) of additivity, transferability and locality of molecular properties. Accordingly, model Hamiltonian matrices are used in the approaches under development (called quasi-classical alternatives), wherein algebraic parameters play the role of matrix elements and these are assumed to be transferable for similar atoms and/or atomic orbitals in addition. Further, passing to delocalized descriptions of electronic structures (as usual) is expected to be the main origin of difficulties seeking to formulate quasi-classical alternatives. In the framework of the canonical method of molecular orbitals (MOs), delocalization is shown to be partially avoidable by invoking a recently-suggested approach to sec...

  12. Quasiclassical Coarse Graining and Thermodynamic Entropy

    CERN Document Server

    Gell-Mann, Murray; Gell-Mann, Murray; Hartle, James

    2006-01-01

    Our everyday descriptions of the universe are highly coarse-grained, following only a tiny fraction of the variables necessary for a perfectly fine-grained description. Coarse graining in classical physics is made natural by our limited powers of observation and computation. But in the modern quantum mechanics of closed systems, some measure of coarse graining is inescapable because there are no non-trivial, probabilistic, fine-grained descriptions. This essay explores the consequences of that fact: Quantum theory allows for various coarse-grained descriptions some of which are mutually incompatible. For most purposes, however, we are interested in the small subset of ``quasiclassical descriptions'' defined by ranges of values of averages over small volumes of densities of conserved quantities such as energy and momentum and approximately conserved quantities such as baryon number. The near-conservation of these quasiclassical quantities results in approximate decoherence, predictability, and local equilibriu...

  13. Young adults' trajectories of Ecstasy use: a population based study.

    Science.gov (United States)

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns.

  14. Simulation Study on Fuzzy Control of Rotary Steering Drilling Trajectory

    Directory of Open Access Journals (Sweden)

    Xue Qi-Long

    2012-07-01

    Full Text Available The purpose of this study is to establish a control method to make borehole trajectory smoother. Considering that the complexity of rotary steerable drilling trajectory control and uncertainty of underground work, analysis of the deficiencies for the traditional trajectory control and the rotary steerable drilling trajectory deviation vector control theory, introduced the concept of "trend Angle", combined with the deviation vector as joint control variables, using fuzzy control algorithm that established of rotary steerable drilling trajectory fuzzy control model. Designed the fuzzy controller using Matlab/Simulink toolbox and dynamic simulation analysis for the fuzzy control systems, simulation results show that the designed fuzzy controller can effectively track the well path design, has a strong adaptability and control results is better than traditional PID control method.

  15. Andreev bound states. Some quasiclassical reflections

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y., E-mail: yiriolin@illinois.edu; Leggett, A. J. [University of Illinois at Urhana-Champaign, Dept. of Physics (United States)

    2014-12-15

    We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.

  16. Common trajectories of physical functioning in the doetinchem cohort study

    NARCIS (Netherlands)

    Rooth, Vera; Van Oostrom, Sandra H.; Deeg, Dorly J H; Monique Verschuren, W. M.; Picavet, H. Susan J

    2016-01-01

    Purpose: To describe common trajectories of physical functioning and their determinants among an adult cohort, followed over a period of 15 years. Methods: The study sample consisted of 4,123 participants (initial ages 26-70 years) from the Doetinchem Cohort Study, who participated in three or four

  17. Adaptive Coarse Graining, Environment, Strong Decoherence, and Quasiclassical Realms

    CERN Document Server

    Gell-Mann, Murray

    2013-01-01

    Three ideas are introduced that when brought together characterize the realistic quasiclassical realms of our quantum universe as particular kinds of sets of alternative coarse-grained histories defined by quasiclassical variables: (1) Branch dependent adaptive coarse grainings that can be close to maximally refined and can simplify calculation. (2) Narrative coarse grainings that describe how features of the universe change over time and allow the construction of an environment. (3) A notion of strong decoherence that characterizes realistic mechanisms of decoherence.

  18. Quasiclassical Theory and Simulations of Strongly Coupled Plasmas

    OpenAIRE

    Ebeling, W.; Ortner, J.

    1999-01-01

    A survey on the dynamical and thermodynamical properties of plasmas with strong Coulomb interactions in the quasi-classical density-temperature region is given. First the basic theoretical concepts describing nonideality are discussed. The chemical picture is introduced. It is shown that the nonideal plasma subsystem of the free charges has a rather large quasi-classical regime, where the quantum effects yield only corrections to the merely classical dynamics. The plasma of free charges may b...

  19. Study on Control Algorithm for Continuous Segments Trajectory Interpolation

    Institute of Scientific and Technical Information of China (English)

    SHI Chuan; YE Peiqing; LV Qiang

    2006-01-01

    In CNC machining, the complexity of the part contour causes a series of problems including the repeated start-stop of the motor, low machining efficiency, and poor machining quality. To relieve those problems, a new interpolation algorithm was put forward to realize the interpolation control of continuous sections trajectory. The relevant error analysis of the algorithm was also studied. The feasibility of the algorithm was proved by machining experiment using a laser machine to carve the interpolation trajectory in the CNC system GT100. This algorithm effectively improved the machining efficiency and the contour quality.

  20. Trajectory data analyses for pedestrian space-time activity study.

    Science.gov (United States)

    Qi, Feng; Du, Fei

    2013-01-01

    It is well recognized that human movement in the spatial and temporal dimensions has direct influence on disease transmission(1-3). An infectious disease typically spreads via contact between infected and susceptible individuals in their overlapped activity spaces. Therefore, daily mobility-activity information can be used as an indicator to measure exposures to risk factors of infection. However, a major difficulty and thus the reason for paucity of studies of infectious disease transmission at the micro scale arise from the lack of detailed individual mobility data. Previously in transportation and tourism research detailed space-time activity data often relied on the time-space diary technique, which requires subjects to actively record their activities in time and space. This is highly demanding for the participants and collaboration from the participants greatly affects the quality of data(4). Modern technologies such as GPS and mobile communications have made possible the automatic collection of trajectory data. The data collected, however, is not ideal for modeling human space-time activities, limited by the accuracies of existing devices. There is also no readily available tool for efficient processing of the data for human behavior study. We present here a suite of methods and an integrated ArcGIS desktop-based visual interface for the pre-processing and spatiotemporal analyses of trajectory data. We provide examples of how such processing may be used to model human space-time activities, especially with error-rich pedestrian trajectory data, that could be useful in public health studies such as infectious disease transmission modeling. The procedure presented includes pre-processing, trajectory segmentation, activity space characterization, density estimation and visualization, and a few other exploratory analysis methods. Pre-processing is the cleaning of noisy raw trajectory data. We introduce an interactive visual pre-processing interface as well as an

  1. Quantum interference between H + D2 quasiclassical reaction mechanisms.

    Science.gov (United States)

    Jambrina, Pablo G; Herráez-Aguilar, Diego; Aoiz, F Javier; Sneha, Mahima; Jankunas, Justinas; Zare, Richard N

    2015-08-01

    Interferences are genuine quantum phenomena that appear whenever two seemingly distinct classical trajectories lead to the same outcome. They are common in elastic scattering but are seldom observable in chemical reactions. Here we report experimental measurements of the state-to-state angular distribution for the H + D2 reaction using the 'photoloc' technique. For products in low rotational and vibrational states, a characteristic oscillation pattern governs backward scattering. The comparison between the experiments, rigorous quantum calculations and classical trajectories on an accurate potential energy surface allows us to trace the origin of that structure to the quantum interference between different quasiclassical mechanisms, a phenomenon analogous to that observed in the double-slit experiment.

  2. Trajectories of picky eating during childhood : A general population study

    NARCIS (Netherlands)

    Cano, Sebastian Cardona; Tiemeier, Henning; Van Hoeken, Daphne; Tharner, Anne; Jaddoe, Vincent W. V.; Hofman, Albert; Verhulst, Frank C.; Hoek, Hans W.

    2015-01-01

    ObjectiveThis cohort study describes the prevalence of picky eating and examines prognostic factors for picky eating trajectories during childhood. Methods4,018 participants of a population-based cohort with measurements from pregnancy onwards were included. Picky eating was assessed by maternal rep

  3. Comparison study of sub-trajectory clustering in data mining

    Science.gov (United States)

    Yang, Guodong; Huang, Zhitao; Wang, Xiang

    2017-06-01

    Trajectory clustering is an important method to achieve moving object data mining, multi-sensor information fusion and trajectory knowledge discovery. Sub-trajectory clustering is an important method to extract useful information from a large number of trajectory data in trajectory analysis. In this paper, comparative experiments are made on the time consumption, similarity measure and clustering performance based on the existing sub-trajectory clustering methods. Based on the comparisons, the advantages and disadvantages of different methods are presented and an improved method is proposed for dealing with trajectories with low positioning accuracy and correlating tracklets from asynchronous sensors. Besides, a general framework of trajectory data mining is discussed.

  4. Quasiclassical analysis of Bloch oscillations in non-Hermitian tight-binding lattices

    CERN Document Server

    Graefe, E M; Rush, A

    2016-01-01

    Many features of Bloch oscillations in one-dimensional quantum lattices with a static force can be described by quasiclassical considerations for example by means of the acceleration theorem, at least for Hermitian systems. Here the quasiclassical approach is extended to non-Hermitian lattices, which are of increasing interest. The analysis is based on a generalised non-Hermitian phase space dynamics developed recently. Applications to a single-band tight-binding system demonstrate that many features of the quantum dynamics can be understood from this classical description qualitatively and even quantitatively. Two non-Hermitian and $PT$-symmetric examples are studied, a Hatano-Nelson lattice with real coupling constants and a system with purely imaginary couplings, both for initially localised states in space or in momentum. It is shown that the time-evolution of the norm of the wave packet and the expectation values of position and momentum can be described in a classical picture.

  5. Adiponectin trajectories before type 2 diabetes diagnosis: Whitehall II study.

    Science.gov (United States)

    Tabák, Adam G; Carstensen, Maren; Witte, Daniel R; Brunner, Eric J; Shipley, Martin J; Jokela, Markus; Roden, Michael; Kivimäki, Mika; Herder, Christian

    2012-12-01

    The role of adiponectin in the natural history of diabetes is not well characterized. We set out to characterize prediagnosis trajectories of adiponectin in individuals who develop type 2 diabetes. In a case-cohort study (335 incident diabetes case and 2,474 noncase subjects) nested in the Whitehall II study, serum adiponectin was measured up to three times per participant (1991-1993, 1997-1999, and 2003-2004). Multilevel models adjusted for age and ethnicity were fitted to assess 13-year trajectories of log-transformed adiponectin preceding diabetes diagnosis or a randomly selected time point during follow-up (year(0)) based on 755/5,095 (case/noncase) person-examinations. Adiponectin levels were lower in diabetes case than in noncase subjects (median 7,141 [interquartile range 5,187-10,304] vs. 8,818 [6,535-12,369] ng/mL at baseline, P obesity, whereas the sex-specific slope differences were independent of obesity. Lower adiponectin levels were observed already a decade before the diagnosis of diabetes. The marked sex difference in trajectories suggests that sex-specific mechanisms affect the association between adiponectin levels and diabetes development.

  6. Adaptive coarse graining, environment, strong decoherence, and quasiclassical realms

    Science.gov (United States)

    Gell-Mann, Murray; Hartle, James B.

    2014-05-01

    Three ideas are introduced that when brought together characterize the realistic quasiclassical realms of our quantum universe as particular kinds of sets of alternative coarse-grained histories defined by quasiclassical variables: (i) branch-dependent adaptive coarse grainings that can be close to maximally refined and can simplify calculation, (ii) narrative coarse grainings that describe how features of the universe change over time and allow the construction of an environment, and (iii) a notion of strong decoherence that characterizes realistic mechanisms of decoherence.

  7. Quantum and quasiclassical dynamics of the multi-channel H + H2S reaction

    Science.gov (United States)

    Qi, Ji; Lu, Dandan; Song, Hongwei; Li, Jun; Yang, Minghui

    2017-03-01

    The prototypical multi-channel reaction H + H2S → H2 + SH/H + H2S has been investigated using the full-dimensional quantum scattering and quasi-classical trajectory methods to unveil the underlying competition mechanism between different product channels and the mode specificity. This reaction favors the abstraction channel over the exchange channel. For both channels, excitations in the two stretching modes promote the reaction with nearly equal efficiency and are more efficient than the bending mode excitation. However, they are all less efficient than the translational energy. In addition, the experimentally observed non-Arrhenius temperature dependence of the thermal rate constants is reasonably reproduced by the quantum dynamics calculations, confirming that the non-Arrhenius behavior is caused by the pronounced quantum tunneling.

  8. Reaction of protonated tyrosine with electronically excited singlet molecular oxygen (a1Delta(g)): an experimental and trajectory study.

    Science.gov (United States)

    Fang, Yigang; Liu, Jianbo

    2009-10-22

    Reaction of protonated tyrosine with the lowest electronically excited singlet state of molecular oxygen, (1)O(2) (a(1)Delta(g)), is reported over the center-of-mass collision energy (E(col)) range from 0.1 to 3.0 eV, using an electrospray-ionization, guided-ion-beam scattering instrument, in conjunction with ab initio electronic structure calculations and direct dynamics trajectory simulations. Only one product channel is observed, corresponding to generation of hydrogen peroxide via transfer of two hydrogen atoms from protonated tyrosine. Despite being exoergic, the reaction is in competition with physical quenching of (1)O(2) and is very inefficient. At low E(col), the reaction may be mediated by intermediate complexes and shows strong inhibition by collision energy. At high E(col), the reaction efficiency drops to approximately 1% and starts to have contribution from a direct mechanism. Quasi-classical trajectory simulations were performed to probe the mechanism at high collision energies. Analysis of trajectories shows that, at E(col) of 3.0 eV, a small fraction of hydrogen peroxide (25%) is produced via a direct, concerted mechanism where two hydrogen atoms are transferred simultaneously, but most hydrogen peroxide (75%) is formed by dissociation of hydroperoxide intermediates. According to ab initio calculations and trajectory simulations, collisions also lead to formation of various endoperoxides, and dissociation of endoperoxides may play a role in physical quenching of (1)O(2). The apparatus and experimental techniques are described in detail.

  9. Guidance and dispersion studies of National Launch System ascent trajectories

    Science.gov (United States)

    Hanson, John M.; Shrader, M. W.; Chang, Hopen; Freeman, Scott E.

    1992-01-01

    The National Launch System (NLS) is a joint concept, between DoD and NASA, for building a family of new launch vehicles. Two of the many choices to be made are the trajectory shaping methods and the onboard guidance scheme. This paper presents results from some ongoing studies to address these issues. First, potential gains from new guidance concepts are listed. Next the paper gives a list of possible discriminators between different guidance schemes, lists a number of potential guidance schemes, and explains two in some detail. A reference scheme is tested to determine its performance versus the discriminators. Finally, results from some special studies using the reference guidance scheme are given, including the effects of closed-loop guidance initiation time, time of enforcement of sideslip, vehicle roll for engine out, time and location of an engine out, use of load relief control, and use of day of launch wind biasing.

  10. APPROACHES TO STUDY EDUCATIONAL AND OCCUPATIONAL TRAJECTORIES AND OUTCOMES

    Directory of Open Access Journals (Sweden)

    Tovar-García, Edgar Demetrio

    2012-04-01

    Full Text Available This article analyzes the main approaches to study educational and occupational outcomes and trajectories. Young people have to decide when and what to study, later on, where to work. Their life levels will depend on those decisions, but the different ways that in both areas they are able to take and their outcomes in education and in the labor market depend on various factors. Among explications it is possible to identify six large approaches: human capital from economics, cultural and social capital from sociology, the socioeconomic status or familiar background approach and the educational and psychological approaches. These approaches are not contrary necessarily, they can be complementary, and their explanatory power depends on place and time, however, the literature does not have an effort to present together their contributions, methodologies and empirical results. This work seeks to remedy that situation and to point out some methodological and empirical weakness.

  11. Study of Trajectory of Spin-Stabilised Artillery Projectiles

    Directory of Open Access Journals (Sweden)

    M. Krishnamurthy

    1991-10-01

    Full Text Available Equations of motion for conventional spin-stabilised artillery projectile have been derived using a pseudo-stability axes system in addition to body-fixed and space-fixed axes systems. The aerodynamic forces and moments have been represented by their respective coefficients and the effects of Mach number and Reynolds number have been suitably accounted. The magnus terms which are significant at high rates of spin are estimated using a simple model. The set of equations have been partly linearised and solved numerically for a typical projectile using NAG system routines. Various trajectory parameters are computed and compared with the range-table data for the projectile. A parametric study had been carried out varying the aerodynamic coefficients to understand the sensitivity of the results obtained.

  12. The dynamics of the H(+) + D(2) reaction: a comparison of quantum mechanical wavepacket, quasi-classical and statistical-quasi-classical results.

    Science.gov (United States)

    Jambrina, P G; Aoiz, F J; Bulut, N; Smith, Sean C; Balint-Kurti, G G; Hankel, M

    2010-02-01

    A detailed study of the proton exchange reaction H(+) + D(2)(v = 0, j = 0) --> HD + D(+) on its ground 1(1)A' potential energy surface has been carried out using 'exact' close-coupled quantum mechanical wavepacket (WP-EQM), quasi-classical trajectory (QCT), and statistical quasi-classical trajectory (SQCT) calculations for a range of collision energies starting from the reaction threshold to 1.3 eV. The WP-EQM calculations include all total angular momenta up to J(max) = 50, and therefore the various dynamical observables are converged up to 0.6 eV. It has been found that it is necessary to include all Coriolis couplings to obtain reliable converged results. Reaction probabilities obtained using the different methods are thoroughly compared as a function of the total energy for a series of J values. Comparisons are also made of total reaction cross sections as function of the collision energy, and rate constants. In addition, opacity functions, integral cross sections (ICS) and differential cross sections (DCS) are presented at 102 meV, 201.3 meV and 524.6 meV collision energy. The agreement between the three sets of results is only qualitative. The QCT calculations fail to describe the overall reactivity and most of the dynamical observables correctly. At low collision energies, the QCT method is plagued by the lack of conservation of zero point energy, whilst at higher collision energies and/or total angular momenta, the appearance of an effective repulsive potential associated with the centrifugal motion "over" the well causes a substantial decrease of the reactivity. In turn, the statistical models overestimate the reactivity over the whole range of collision energies as compared with the WP-EQM method. Specifically, at sufficiently high collision energies the reaction cannot be deemed to be statistical and important dynamical effects seem to be present. In general the WP-EQM results lie in between those obtained using the QCT and SQCT methods. One of the main

  13. Ultrarelativistic quasiclassical wave functions in strong laser and atomic fields

    CERN Document Server

    Di Piazza, A

    2014-01-01

    The problem of an ultrarelativistic charge in the presence of an atomic and a plane-wave field is investigated in the quasiclassical regime by including exactly the effects of both background fields. Starting from the quasiclassical Green's function obtained in [Phys. Lett. B \\textbf{717}, 224 (2012)], the corresponding in- and out-wave functions are derived in the experimentally relevant case of the particle initially counterpropagating with respect to the plane wave. The knowledge of these electron wave functions opens the possibility of investigating a variety of problems in strong-field QED, where both the atomic field and the laser field are strong enough to be taken into account exactly from the beginning in the calculations.

  14. Quasiclassical Theory of Twin Boundaries in High-Tc Superconductors

    OpenAIRE

    Belzig, Wolfgang; Bruder, Christoph; Sigrist, Manfred

    1998-01-01

    We investigate the electronic structure of twin boundaries in orthorhombically distorted high-T$_c$ materials using the quasiclassical theory of superconductivity. At low temperatures we find a local instability to a time-reversal symmetry breaking state at the twin boundary. This state yields spontaneous currents along the twin boundary that are microscopically explained by the structure of the quasiparticle bound states. We calculate the local density of states and find a splitting in the z...

  15. Determination of the effective kinematic viscosity for the decay of quasiclassical turbulence in superfluid 4He

    Science.gov (United States)

    Gao, J.; Guo, W.; Vinen, W. F.

    2016-09-01

    The energy dissipation of quasiclassical homogeneous turbulence in superfluid 4He (He II) is controlled by an effective kinematic viscosity ν', which relates the energy decay rate d E /d t to the density of quantized vortex lines L as d E /d t =-ν'(κL ) 2 . The precise value of ν' is of fundamental importance in developing our understanding of the dissipation mechanism in He II, and it is also needed in many high-Reynolds-number turbulence experiments and model testing that use He II as the working fluid. However, a reliable determination of ν' requires the measurements of both E (t ) and L (t ) , which was never achieved. Here we discuss our study of the quasiclassical turbulence that emerges in the decay of thermal counterflow in He II above 1 K. We were able to measure E (t ) by using a recently developed flow-visualization technique and L (t ) via second-sound attenuation. We report the ν' values in a wide temperature range determined from a comparison of the time evolution of E (t ) and L (t ) .

  16. Quasiclassical theory of the vortex state in unconventional systems. Study of magnesium diboride and d-wave superconductors; Quasiklassische Theorie des Vortexzustandes in unkonventionellen Systemen. Betrachtung zu Magnesiumdiborid und d-Wellen-Supraleitern

    Energy Technology Data Exchange (ETDEWEB)

    Graser, S.

    2006-07-01

    The two-band superconductor magnesium diboride as well as the high temperature cuprates belong to the class of type-II superconductors. In these systems between an upper and a lower critical magnetic field one can only find an incomplete Meissner effect und magnetic flux penetrates the superconductor in form of quantized flux tubes, so-called vortices. This work is devoted to the vortex state in magnesium diboride and the interplay of vortices and boundaries in d-wave superconductors. First of all analytical results for the quasiparticle density of states in high magnetic fields are obtained within the framework of the quasiclassical theory. Especially the influence of the Fermi surface topology on the spatially averaged quasiparticle density of states is discussed in detail. Furthermore selfconsistent numerical calculations of the pairing potential around an isolated vortex - a model of the vortex state in the vicinity of the lower critical field - are performed. In this context the unusual shrinkage of the vortex core with decreasing temperature, visible only in very clean superconductors and known as the Kramer-Pesch-effect, is examined for a two-band system. The last chapter is concerned with the influence of the flow-field of an isolated phase vortex on the Andreev bound states at the surface of a d-wave superconductor. The local suppression of the Andreev bound states in a shadow-like region between vortex and boundary is the main result and consequences of this ''vortexshadow-effect'' are discussed. (orig.)

  17. Aging Trajectories in Different Body Systems Share Common Environmental Etiology : The Healthy Aging Twin Study (HATS)

    NARCIS (Netherlands)

    Moayyeri, Alireza; Hart, Deborah J.; Snieder, Harold; Hammond, Christopher J.; Spector, Timothy D.; Steves, Claire J.

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal

  18. A Quasiclassical Approximation in the Theory of the Landau-Pomeranchuk Effect

    CERN Document Server

    Tarasov, A V; Voskresenskaya, O O

    2012-01-01

    With the use of revised within the quasiclassical approximation the values of parameters of the Moliere multiple scattering theory it is shown that the best agreement of the Migdal theory of the LPM-effect with experiment achieved if to describe the electron-atomic scattering the quasiclassical approximation is used instead of the traditionally used Born one.

  19. Chaos in a quasiclassical hadronic atom

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, F.; Casati, G. [Dipartimento di Fisica dellUniversita, Via Castelnuovo 7, 22100 Como (Italy); Shepelyansky, D.L. [Laboratoire de Physique Quantique, Universite Paul Sabatier, 31062, Toulouse (France)

    1996-02-01

    We investigate the classical dynamics of the helium atom in which one electron is replaced by a heavy particle with a negative charge, such as an antiproton. The general properties of motion and the conditions for chaotic dynamics are studied via the derivation of the planetary map. The regime of strongly correlated motion of two particles is also analyzed. The properties of quantum motion are briefly discussed. {copyright} {ital 1996 The American Physical Society.}

  20. Congenitally Deaf Children's Care Trajectories in the Context of Universal Neonatal Hearing Screening: A Qualitative Study of the Parental Experiences

    Science.gov (United States)

    Hardonk, Stefan; Desnerck, Greetje; Loots, Gerrit; Van Hove, Geert; Van Kerschaver, Erwin; Sigurjonsdottir, Hanna Bjorg; Vanroelen, Christophe; Louckx, Fred

    2011-01-01

    The objective of this study is to examine the early care trajectories of congenitally deaf children from a parental perspective, starting with universal neonatal hearing screenings. The analysis using a three-dimensional care trajectory concept is aimed at developing a basic typology of postscreening care trajectories. Children with…

  1. Hybrid trajectory spaces

    NARCIS (Netherlands)

    Collins, P.J.

    2005-01-01

    In this paper, we present a general framework for describing and studying hybrid systems. We represent the trajectories of the system as functions on a hybrid time domain, and the system itself by its trajectory space, which is the set of all possible trajectories. The trajectory space is given a na

  2. Quasi-classical theory of electronic flux density in electronically adiabatic molecular processes.

    Science.gov (United States)

    Diestler, D J

    2012-11-26

    The standard Born-Oppenheimer (BO) description of electronically adiabatic molecular processes predicts a vanishing electronic flux density (EFD). A previously proposed "coupled-channels" theory permits the extraction of the EFD from the BO wave function for one-electron diatomic systems, but attempts at generalization to many-electron polyatomic systems are frustrated by technical barriers. An alternative "quasi-classical" approach, which eliminates the explicit quantum dynamics of the electrons within a classical framework, yet retains the quantum character of the nuclear motion, appears capable of yielding EFDs for arbitrarily complex systems. Quasi-classical formulas for the EFD in simple systems agree with corresponding coupled-channels formulas. Results of the application of the new quasi-classical formula for the EFD to a model triatomic system indicate the potential of the quasi-classical scheme to elucidate the dynamical role of electrons in electronically adiabatic processes in more complex multiparticle systems.

  3. Feasibility study of a single, elliptical heliocentric Earth-Mars trajectory

    Science.gov (United States)

    Blake, M.; Fulgham, K.; Westrup, S.

    1989-01-01

    The initial intent of this design project was to evaluate the existence and feasibility of a single elliptical heliocentric Earth/Mars trajectory. This trajectory was constrained to encounter Mars twice in its orbit, within a time interval of 15 to 180 Earth days between encounters. The single ellipse restriction was soon found to be prohibitive for reasons shown later. Therefore, the approach taken in the design of the round-trip mission to Mars was to construct single-leg trajectories which connected two planets on two prescribed dates. Three methods of trajectory design were developed. Method 1 is an eclectic approach and employs Gaussian Orbit Determination (Method 1A) and Lambert-Euler Preliminary Orbit Determination (Method 1B) in conjunction with each other. Method 2 is an additional version of Lambert's Solution to orbit determination, and both a coplanar and a noncoplanar solution were developed within Method 2. In each of these methods, the fundamental variables are two position vectors and the time between the position vectors. In all methods, the motion was considered Keplerian motion and the reference frame origin was located at the sun. Perturbative effects were not considered in Method 1. The feasibility study of round-trip Earth/Mars trajectories maintains generality by considering only heliocentric trajectory parameters and planetary approach conditions. The coordinates and velocity components of the planets, for the standard epoch J2000, were computed from an approximate set of osculating elements by the procedure outlined in an ephemeris of coordinates.

  4. A study into lowering beam trajectories in P01

    Energy Technology Data Exchange (ETDEWEB)

    Sondgeroth, A.

    1995-09-01

    This document describes what changes would be needed to lower the primary beams coming from switchyard into enclosure P01 without changing trajectories in the downstream enclosures. There is a 680 foot pipe buried in the ground between Enclosure E and P01 which allows primary beam to travel from the switchyard area to the research division area. This pipe is approximately 25 years old and has started to leak. The effects of the leaky pipe can be catastrophic to the transportation of the proton area beams. The vacuum group has devised an ingenious way of repairing a leak from the inside using remotely controlled grinders, patchers, welders and cameras mounted on carts that can be pulled into the pipe. A typical patch adds approximately one half of an inch of material which, in turn, restricts the aperture of the pipe. This pipe has three separate beams running through it split in the vertical plane. Pwest is the highest beam in the pipe and, in at least one location, the center of the beam clears the top of the pipe by one and one half inches. If a leak were to develop at a low spot in the pipe the patch to fix the leak might create an obstruction for the beam. Hence, the request from the Research Division Head.

  5. Aging Trajectories in Different Body Systems Share Common Environmental Etiology: The Healthy Aging Twin Study (HATS).

    Science.gov (United States)

    Moayyeri, Alireza; Hart, Deborah J; Snieder, Harold; Hammond, Christopher J; Spector, Timothy D; Steves, Claire J

    2016-02-01

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal clinical data were collected on 3,508 female twins in the TwinsUK registry (complete pairs:740 monozygotic (MZ), 986 dizygotic (DZ), mean age at entry 48.9 ± 10.4, range 18-75 years; mean follow-up 10.2 ± 2.8 years, range 4-17.8 years). Panel data on multiple age-related variables were used to estimate biological ages for each individual at each time point, in linear mixed effects models. A weighted average approach was used to combine variables within predefined body system groups. Aging trajectories for each system in each individual were then constructed using linear modeling. Multivariate structural equation modeling of these aging trajectories showed low genetic effects (heritability), ranging from 2% in metabolic aging to 22% in cardiovascular aging. However, we found a significant effect of shared environmental factors on the variations in aging trajectories in cardiovascular (54%), skeletal (34%), morphometric (53%), and metabolic systems (53%). The remainder was due to environmental factors unique to each individual plus error. Multivariate Cholesky decomposition showed that among aging trajectories for various body systems there were significant and substantial correlations between the unique environmental latent factors as well as shared environmental factors. However, there was no evidence for a single common factor for aging. This study, the first of its kind in aging, suggests that diverse organ systems share non-genetic sources of variance for aging trajectories. Confirmatory studies are needed using population-based twin cohorts and alternative methods of handling missing data.

  6. Trajectories of Substance Use Disorder in Youth After Detention: A 12-Year Longitudinal Study.

    Science.gov (United States)

    Welty, Leah J; Hershfield, Jennifer A; Abram, Karen M; Han, Hongyun; Byck, Gayle R; Teplin, Linda A

    2017-02-01

    To identify trajectories of substance use disorders (SUDs) in youth during the 12 years after detention and how gender, race/ethnicity, and age at baseline predict trajectories. As part of the Northwestern Juvenile Project, a longitudinal study of 1,829 youth randomly sampled from detention in Chicago, Illinois from 1995 through 1998, participants were reinterviewed in the community or correctional facilities up to 9 times over 12 years. Independent interviewers assessed SUDs using the Diagnostic Interview Schedule for Children 2.3 (baseline) and the Diagnostic Interview Schedule IV (follow-ups). Primary outcome was a mutually exclusive 5-category typology of disorder: no SUD, alcohol alone, marijuana alone, comorbid alcohol and marijuana, or "other" illicit ("hard") drug. Trajectories were estimated using growth mixture models with a 3-category ordinal variable derived from the typology. During the 12-year follow-up, 19.6% of youth did not have an SUD. The remaining 81.4% were in 3 trajectory classes. Class 1 (24.5%), a bell-shaped trajectory, peaked 5 years after baseline when 42.7% had an SUD and 12.5% had comorbid or "other" illicit drug disorders. Class 2 (41.3%) had a higher prevalence of SUD at baseline, 73.8%. Although prevalence decreased over time, 23.5% had an SUD 12 years later. Class 3 (14.6%), the most serious and persistent trajectory, had the highest prevalence of comorbid or "other" illicit drug disorders-52.1% at baseline and 17.4% 12 years later. Males, Hispanics, non-Hispanic whites, and youth who were older at baseline (detention) had the worst outcomes. Gender, race/ethnicity, and age at detention predict trajectories of SUDs in delinquent youth. Findings provide an empirical basis for child psychiatry to address health disparities and improve prevention. Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  7. A modelling and experimental study of the bubble trajectory in a non-Newtonian crystal suspension

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, N M S [Process Engineering and Light Metals (PELM) Centre, Faculty of Sciences, Engineering and Health, CQUniversity, Rockhampton, QLD 4702 (Australia); Khan, M M K; Rasul, M G, E-mail: m.rasul@cqu.edu.a [School of Engineering and Built Environment, Faculty of Sciences, Engineering and Health, CQUniversity, Rockhampton, QLD 4702 (Australia)

    2010-12-15

    This paper presents an experimental and computational study of air bubbles rising in a massecuite-equivalent non-Newtonian crystal suspension. The bubble trajectory inside the stagnant liquid of a 0.05% xanthan gum crystal suspension was investigated and modelled using the computational fluid dynamics (CFD) model to gain an insight into the bubble flow characteristics. The CFD code FLUENT was used for numerical simulation, and the bubble trajectory calculations were performed through a volume of fluid (VOF) model. The influences of the Reynolds number (Re), the Weber number (We) and the bubble aspect ratio (E) on the bubble trajectory are discussed. The conditions for the bubbles' path oscillations are identified. The experimental results showed that the path instability for the crystal suspension was less rapid than in water. The trajectory analysis indicated that 5.76 mm diameter bubbles followed a zigzag motion in the crystal suspension. Conversely, the smaller bubbles (5.76 mm) followed a path of least horizontal movement and larger bubbles (21.21 mm) produced more spiral motion within the crystal suspension. Path instability occurred for bubbles of 15.63 and 21.21 mm diameter, and they induced both zigzag and spiral trajectories within the crystal suspension. At low Re and We, smaller bubbles (5.76 mm) produced a zigzag trajectory, whereas larger bubbles (15.63 and 21.21 mm) showed both zigzag and spiral trajectories at intermediate and moderately high Re and We in the crystal suspension. The simulation results illustrated that a repeating pattern of swirling vortices was created for smaller bubbles due to the unstable wake and unsteady flow of these bubbles. This is the cause of the smaller bubbles moving in a zigzag way. Larger bubbles showed two counter-rotating trailing vortices at the back of the bubble. These vortices induced a velocity component to the gas-liquid interface and caused a deformation. Hence, the larger bubbles produced a path

  8. Quantum-trajectory Monte Carlo method for study of electron-crystal interaction in STEM.

    Science.gov (United States)

    Ruan, Z; Zeng, R G; Ming, Y; Zhang, M; Da, B; Mao, S F; Ding, Z J

    2015-07-21

    In this paper, a novel quantum-trajectory Monte Carlo simulation method is developed to study electron beam interaction with a crystalline solid for application to electron microscopy and spectroscopy. The method combines the Bohmian quantum trajectory method, which treats electron elastic scattering and diffraction in a crystal, with a Monte Carlo sampling of electron inelastic scattering events along quantum trajectory paths. We study in this work the electron scattering and secondary electron generation process in crystals for a focused incident electron beam, leading to understanding of the imaging mechanism behind the atomic resolution secondary electron image that has been recently achieved in experiment with a scanning transmission electron microscope. According to this method, the Bohmian quantum trajectories have been calculated at first through a wave function obtained via a numerical solution of the time-dependent Schrödinger equation with a multislice method. The impact parameter-dependent inner-shell excitation cross section then enables the Monte Carlo sampling of ionization events produced by incident electron trajectories travelling along atom columns for excitation of high energy knock-on secondary electrons. Following cascade production, transportation and emission processes of true secondary electrons of very low energies are traced by a conventional Monte Carlo simulation method to present image signals. Comparison of the simulated image for a Si(110) crystal with the experimental image indicates that the dominant mechanism of atomic resolution of secondary electron image is the inner-shell ionization events generated by a high-energy electron beam.

  9. Outcomes of childhood conduct problem trajectories in early adulthood : findings from the ALSPAC study

    NARCIS (Netherlands)

    Kretschmer, Tina; Hickman, Matthew; Doerner, Rita; Emond, Alan; Lewis, Glyn; Macleod, John; Maughan, Barbara; Munafo, Marcus R.; Heron, Jon

    Although conduct problems in childhood are stably associated with problem outcomes, not every child who presents with conduct problems is at risk. This study extends previous studies by testing whether childhood conduct problem trajectories are predictive of a wide range of other health and behavior

  10. Research Review: A Critical Review of Studies on the Developmental Trajectories of Antisocial Behavior in Females

    Science.gov (United States)

    Fontaine, Nathalie; Carbonneau, Rene; Vitaro, Frank; Barker, Edward D.; Tremblay, Richard E.

    2009-01-01

    Background: Knowledge on the onset and the development of antisocial behavior in females is limited, because most of the research in this domain is based on males. Methods: We critically reviewed 46 empirical studies that examined developmental trajectories of antisocial behavior in females, notably to help determine whether or not an…

  11. Developmental trajectories of social participation in individuals with cerebral palsy : A multicentre longitudinal study

    NARCIS (Netherlands)

    Tan, Siok Swan; Wiegerink, Diana J H G; Vos, Rimke C.; Smits, Dirk Wouter; Voorman, Jeanine M.; Twisk, Jos W R; Ketelaar, Marjolijn; Roebroeck, Marij E.; Dallmeijer, A. J.; Vos, R. C.; Van Eck, M.; Van Schie, P.; Voorman, J. M.; Becher, J. G.; Schuengel, C.; Ketelaar, M.; Smits, D. W.; Lindeman, E.; Jongmans, M.; Roebroeck, M. E.; Tan, S. S.; Wiegerink, D. J H G; Van Meeteren, J.; Reinders-Messelink, H. A.; Gorter, J. W.; Verheijden, J.

    2014-01-01

    Aim: This study aimed to determine the developmental trajectories of social participation, by level of gross motor function and intellectual disability, in a Dutch population of individuals with cerebral palsy (CP) aged 1 to 24 years. Method: As part of the Pediatric Rehabilitation Research in the N

  12. Career Trajectories of Dutch Pop Musicians: A Longitudinal Study

    Science.gov (United States)

    Zwaan, Koos; ter Bogt, Tom F. M.; Raaijmakers, Quinten

    2010-01-01

    Systematic studies of artistic careers are scarce and this is the first large-scale study on the career development of pop musicians. Using a prospective longitudinal approach we followed a sample of aspiring pop musicians in the Netherlands (N=369) over a three-year period. First we identified four groups of pop musicians with different career…

  13. Career Trajectories of Dutch Pop Musicians: A Longitudinal Study

    Science.gov (United States)

    Zwaan, Koos; ter Bogt, Tom F. M.; Raaijmakers, Quinten

    2010-01-01

    Systematic studies of artistic careers are scarce and this is the first large-scale study on the career development of pop musicians. Using a prospective longitudinal approach we followed a sample of aspiring pop musicians in the Netherlands (N=369) over a three-year period. First we identified four groups of pop musicians with different career…

  14. Trajectories of schizotypy and their emotional and social functioning: An 18-month follow-up study.

    Science.gov (United States)

    Wang, Yi; Shi, Hai-Song; Liu, Wen-Hua; Xie, Dong-Jie; Geng, Fu-Lei; Yan, Chao; Wang, Ya; Xiao, Ya-Hui; So, Suzanne H W; Chiu, Chui-De; Leung, Patrick W L; Cheung, Eric F C; Gooding, Diane C; Chan, Raymond C K

    2017-07-24

    Schizotypy is a set of personality traits that convey liability to develop schizophrenia. Studying schizotypy in healthy individuals may facilitate the understanding of the psychopathological processes underlying schizophrenia. The present study aimed to examine the developmental trajectories of schizotypy over time using a longitudinal study design. The Chapman Scales for Psychosis Proneness were administered to 1541 college students at baseline, and subsequently at six-monthly intervals up to 18months. Latent class growth analysis was conducted to track the different trajectories. In addition, self-reported scales were used to measure idea of reference, emotional experiences and expression, stress and coping, as well as social functioning. We identified four latent classes with distinct trajectories: "nonschizotypy" group (LC1), "stable high schizotypy" group (LC3), "high reactive schizotypy" group (LC2) and "low reactive schizotypy" group (LC4). These findings suggest that there may be distinct developmental trajectories for schizotypy. Two groups may be of particular interest: the "stable high schizotypy" group that displayed the worst clinical and functioning outcomes on almost all measures and the "high reactive schizotypy" group characterized by a relatively rapid decline in functioning. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Epigenetic profiling of ADHD symptoms trajectories: A prospective, methylome-wide study

    Science.gov (United States)

    Walton, Esther; Pingault, Jean-Baptiste; Cecil, Charlotte AM; Gaunt, Tom R.; Relton, Caroline; Mill, Jonathan; Barker, Edward D.

    2016-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is a prevalent developmental disorder, associated with a range of long-term impairments. Variation in DNA methylation, an epigenetic mechanism, is implicated in both neurobiological functioning and psychiatric health. However, the potential role of DNA methylation in ADHD symptoms is currently unclear. In this study, we examined data from the Avon Longitudinal Study of Parents and Children (ALSPAC) – specifically the subsample forming the Accessible Resource for Integrated Epigenomics Studies (ARIES) – which includes (i) peripheral measures of DNA methylation (Illumina 450k) at birth (n=817, 49% male) and age 7 (n=892, 50% male) and (ii) trajectories of ADHD symptoms (7-15 yrs). We first employed a genome-wide analysis to test whether DNA methylation at birth associates with later ADHD trajectories; and then followed up at age 7 to investigate the stability of associations across early childhood. We found that DNA methylation at birth differentiated ADHD trajectories across multiple genomic locations, including probes annotated to SKI (involved in neural tube development), ZNF544 (previously implicated in ADHD), ST3GAL3 (linked to intellectual disability) and PEX2 (related to perixosomal processes). None of these probes maintained an association with ADHD trajectories at age 7. Findings lend novel insights into the epigenetic landscape of ADHD symptoms, highlighting the potential importance of DNA methylation variation in genes related to neurodevelopmental and peroxisomal processes, which play a key role in the maturation and stability of cortical circuits. PMID:27217153

  16. Using Large Data Sets to Study College Education Trajectories

    Science.gov (United States)

    Oseguera, Leticia; Hwang, Jihee

    2014-01-01

    This chapter presents various considerations researchers undertook to conduct a quantitative study on low-income students using a national data set. Specifically, it describes how a critical quantitative scholar approaches guiding frameworks, variable operationalization, analytic techniques, and result interpretation. Results inform how…

  17. Characterizing Resilience and Growth Among Soldiers: A Trajectory Study

    Science.gov (United States)

    2014-04-01

    Psychology in the Classroom : A Case of Positive Psychology Intervention for Special Education in High School. Poster presentation. 2013 International... meditation can boost immune function.53 Psychosocial resilience training targeting positive emotions, cognitive flexibility, social support, life meaning...mindfulness meditation . It is assumed that meditations induce positive affect and lead to good health. A study led by a neuroscientist, Richard Davidson

  18. Trajectory study of dissociation reactions. The single-ensemble method. II

    Science.gov (United States)

    Kutz, H. Douglas; Burns, George

    1981-04-01

    The single uniform ensemble method was previously employed in 3D classical trajectory calculations [H. D. Kutz and G. Burns, J. Chem. Phys. 72, 3652 (1980)]. Presently it is applied to the Br2+Ar system to study nonequilbrium effects in diatom dissociation over a wide temperature range. It was found that, for a given large set of trajectories, observables, such as reaction cross sections or rate constants, are indepedent within four significant figures of the initial distribution function. This indicates a high degree of reliability of the single uniform ensemble method, once the choice of a set of trajectories is made. In order to study dissociation from the low lying energy states, the uniform velocity selection method in trajectory calculations was used. It was found that dissociation from these states contributes but little to the overall dissociation reaction. The latter finding is consistent with the attractive nature of the potential energy surface used, and constitutes an argument against those current theories of diatom dissociation reaction which explains experimental data by postulating a high probability of dissociation from low lying energy states of diatoms. It was found that the contribution from the low lying states to dissociation can be estimated with good accuracy using information theory expressions. Temperature dependence of nonequilibrium effects was investigated between 1 500 and 6 000 °K. In this range the nonequilibrium correction factor varies between 0.2 and 0.5. Angular momentum dependence of such observables as reaction rate constant and reaction cross section was investigated.

  19. 10-year trajectories of depressive symptoms and risk of dementia: a population-based study.

    Science.gov (United States)

    Mirza, Saira Saeed; Wolters, Frank J; Swanson, Sonja A; Koudstaal, Peter J; Hofman, Albert; Tiemeier, Henning; Ikram, M Arfan

    2016-07-01

    Late-life depressive symptoms have been extensively studied for their relationship with incident dementia, but have been typically assessed at a single timepoint. Such an approach neglects the course of depression, which, given its remitting and relapsing nature, might provide further insights into the complex association of depression with dementia. We therefore repeatedly measured depressive symptoms in a population of adults over a decade to study the subsequent risk of dementia. Our study was embedded in the Rotterdam Study, a population-based study of adults aged 55 years or older in Rotterdam (Netherlands), ongoing since 1990. The cohort is monitored continuously for major events by data linkage between the study database and general practitioners. We examined a cohort of participants who were free from dementia, but had data for depressive symptoms from at least one examination round in 1993-95, 1997-99, or 2002-04. We assessed depressive symptoms with the validated Dutch version of the Center for Epidemiology Depression Scale (CES-D) and the Hospital Anxiety and Depression Scale-Depression. We used these data to identify 11-year trajectories of depressive symptoms by latent class trajectory modelling. We screened participants for dementia at each examination round and followed up participants for 10 years for incident dementia by latent trajectory from the third examination round to 2014. We calculated hazard ratios (HR) for dementia by assigned trajectory using two Cox proportional hazards models (model 1 adjusted for age and sex only, and model 2 adjusted additionally for APOEɛ4 carrier status, educational level, body-mass index, smoking, alcohol consumption, cognitive score, use of antidepressants, and prevalent disease status at baseline). We repeated the analyses censoring for incident stroke, restricting to Alzheimer's disease as an outcome, and accounting for mortality as a competing risk for dementia. From 1993-2004, we obtained data for depressive

  20. Electron impact double ionization of helium from classical trajectory calculations

    CERN Document Server

    Geyer, T

    2004-01-01

    With a recently proposed quasiclassical ansatz [Geyer and Rost, J. Phys. B 35 (2002) 1479] it is possible to perform classical trajectory ionization calculations on many electron targets. The autoionization of the target is prevented by a M\\o{}ller type backward--forward propagation scheme and allows to consider all interactions between all particles without additional stabilization. The application of the quasiclassical ansatz for helium targets is explained and total and partially differential cross sections for electron impact double ionization are calculated. In the high energy regime the classical description fails to describe the dominant TS1 process, which leads to big deviations, whereas for low energies the total cross section is reproduced well. Differential cross sections calculated at 250 eV await their experimental confirmation.

  1. Computing with spatial trajectories

    CERN Document Server

    2011-01-01

    Covers the fundamentals and the state-of-the-art research inspired by the spatial trajectory data Readers are provided with tutorial-style chapters, case studies and references to other relevant research work This is the first book that presents the foundation dealing with spatial trajectories and state-of-the-art research and practices enabled by trajectories

  2. Quasiclassical propagator of a relativistic particle via the path-dependent gauge potential

    Energy Technology Data Exchange (ETDEWEB)

    Yakaboylu, Enderalp; Hatsagortsyan, Karen Z.; Keitel, Christoph H. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2016-07-01

    The proper time formalism for a particle propagator in an external electromagnetic field is combined with the path-dependent formulation of gauge theory to simplify the quasiclassical propagator of a relativistic particle. The latter is achieved due to a specific choice of gauge corresponding to the use of the classical path in the path-dependent formulation of gauge theory, which leads to cancellation of the interaction part of the classical action in the Feynman path integral. A simple expression for the quasiclassical propagator is obtained in all cases of the external field when the classical equations of motion in this field are integrable. As an example, simple expressions for the propagators are derived for a spinless charged particle interacting with the following fields: an arbitrary constant and uniform electromagnetic field, an arbitrary plane wave, and finally an arbitrary plane wave combined with an arbitrary constant and uniform electromagnetic field. In all these cases the quasiclassical propagator coincides with the exact result.

  3. The method of Gaussian weighted trajectories. V. On the 1GB procedure for polyatomic processes

    CERN Document Server

    Bonnet, Laurent

    2010-01-01

    In recent years, many chemical reactions have been studied by means of the quasi-classical trajectory (QCT) method within the Gaussian binning (GB) procedure. The latter consists in "quantizing" the final vibrational actions in Bohr spirit by putting strong emphasis on the trajectories reaching the products with vibrational actions close to integer values. A major drawback of this procedure is that if N is the number of product vibrational modes, the amount of trajectories necessary to converge the calculations is ~ 10^N larger than with the standard QCT method. Applying it to polyatomic processes is thus problematic. In a recent paper, however, Czako and Bowman propose to quantize the total vibrational energy instead of the vibrational actions [G. Czako and J. M. Bowman, J. Chem. Phys., 131, 244302 (2009)], a procedure called 1GB here. The calculations are then only ~ 10 times more time-consuming than with the standard QCT method, allowing thereby for considerable numerical saving. In this paper, we propose ...

  4. Depressive symptom trajectories in women affected by breast cancer and their male partners : a nationwide prospective cohort study

    NARCIS (Netherlands)

    Rottmann, Nina; Hansen, Dorte Gilsa; Hagedoorn, Mariet; Larsen, Pia Veldt; Nicolaisen, Anne; Bidstrup, Pernille Envold; Wurtzen, Hanne; Flyger, Henrik; Kroman, Niels; Johansen, Christoffer

    2016-01-01

    The purpose of this study was to identify subgroups of breast cancer patients and their partners based on distinct trajectories of depressive symptoms, to examine how relationship quality and medical and sociodemographic factors were associated with these trajectories, and to explore whether

  5. A stochastic quasi-classical wavefunction of the Universe from the third quantization procedure

    CERN Document Server

    Ivanov, P

    2015-01-01

    (abbreviated) We study quantized solutions of WdW equation describing a closed FRW universe with a $\\Lambda $ term and a set of massless scalar fields. We show that when $\\Lambda \\ll 1$ in the natural units and the standard $in$-vacuum state is considered, either wavefunction of the universe, $\\Psi$, or its derivative with respect to the scale factor, $a$, behave as random quasi-classical fields at sufficiently large values of $a$, when $1 \\ll a \\ll e^{{2\\over 3\\Lambda}}$ or $a \\gg e^{{2\\over 3\\Lambda}}$, respectively. Statistical r.m.s value of the wavefunction is proportional to the Hartle-Hawking wavefunction for a closed universe with a $\\Lambda $ term. Alternatively, the behaviour of our system at large values of $a$ can be described in terms of a density matrix corresponding to a mixed state, which is directly determined by statistical properties of $\\Psi$. It gives a non-trivial probability distribution over field velocities. We suppose that a similar behaviour of $\\Psi$ can be found in all models exhi...

  6. Study of Mechanical Model of Sports Ball’S Flight Trajectory and Its Application

    Directory of Open Access Journals (Sweden)

    Xiaoyan Yu

    2013-05-01

    Full Text Available In order to resolve the controversy of ball games the placement problem fined on the other hand, to promote the teaching and training ball flight trajectory. Tennis is the main object of study, use of literature, mathematical statistics and experimental research methods and to establish an appropriate mathematical model, using MATLAB software to accurately determine the trajectory and impact point of the ball's flight, used in teaching, training and competition in. The conclusions show that the law, accurate data analysis using MATLAB software can simulate the flight of the ball moving on sports development has a very good help provide a new way of thinking for the in-depth study the pattern of winning ball games and similar sports teaching, training and selection of athletes is an important complementary and valuable.

  7. A comparison of quantum and quasiclassical statistical models for reactions of electronically excited atoms with molecular hydrogen.

    Science.gov (United States)

    Aoiz, F J; González-Lezana, T; Sáez Rábanos, V

    2008-09-01

    A detailed comparison of statistical models based on the quasiclassical trajectory (SQCT) and quantum mechanical (SQM) methods is presented in this work for the C((1)D)+H(2), S((1)D)+H(2), O((1)D)+H(2) and N((2)D)+H(2) insertion reactions. Reaction probabilities, integral (ICS) and differential (DCS) cross sections at different levels of product's state resolution are shown and discussed for these reactions. The agreement is in most cases excellent and indicates that the effect of tunneling through the centrifugal barrier is negligible. However, if there exists a dynamical barrier, as in the case of the N((2)D)+H(2) reaction, some of the SQM results can be slightly different than those calculated with the SQCT model. The rationale of the observed similarities and discrepancies can be traced back to the specific topologies of the potential energy surfaces for each of the reactions examined. The SQCT model is sensitive enough to show the relatively small inaccuracies resulting from the decoupling inherent to the centrifugal sudden approximation when used in the SQM calculations. In addition, the effect of ignoring the parity conservation is also examined. This effect is in general minor except in particular cases such as the DCS from initial rotational state j=0, which requires, in order to reproduce the sharp forward and backward peaks, the explicit conservation of parity.

  8. Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

    OpenAIRE

    Bineyam Taye; Fikre Enquselassie; Aster Tsegaye; Alemayehu Amberbir; Girmay Medhin; Andrew Fogarty; Karen Robinson; Gail Davey

    2016-01-01

    Background: Helicobacter pylori infection has been associated with early childhood growth impairment in high- and middle-income countries; however, few studies have examined this relationship within low-income countries or have used a longitudinal design. The possible effects of H. pylori infection on growth trajectories were examined in a cohort of young Ethiopian children. Methods: In 2011/12, 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were fo...

  9. Trends and Findings in Trajectory Studies: a Methodological Approach to Classify Labor Development

    Directory of Open Access Journals (Sweden)

    Mariela Sonia Jiménez Vásquez

    2009-05-01

    Full Text Available Trajectory studies are a methodological option that helps to completely analyze labor paths forged by individuals in the labor market. However, when initiating a research in this topic there are several different scopes, discipline approaches, objects and purposes of research, which hinder its comprehension. This article presents the main trends established to guide this type of research and some of the theoretical and methodological elements found in its structure.

  10. Human Spaceflight Trajectory Operations: A Case Study from STS-132/ULF4

    Science.gov (United States)

    Cutri-Kohart, Rebecca; Browns, Ansley

    2010-01-01

    Prior to the launch of the STS-132/ULF4 mission, the International Space Station (ISS) Flight Control Team was alerted to the approach of a space debris with a predicted time of closest approach approximately 1 hr after Space Shuttle docking. As a result, the ISS team considered performing a collision avoidance maneuver prior to the Space Shuttle s approach. The purpose of this presentation will be to use this case study to illustrate best practices of the human spaceflight trajectory operations team. The presentation will begin with an overview of the roles of the real-time ISS and Space Shuttle trajectory flight control teams. Then, the STS-132/ULF4 case study will be used to illustrate the issues and lessons learned involved in performing Space Shuttle rendezvous maneuver planning and execution. Specific elements of the STS-132 Space Shuttle rendezvous maneuver profile that can be used to provide mission assurance in cases of trajectory uncertainty will be described and discussed. Additionally, this case study will be used to provide context for identifying lessons learned in an operational environment that requires technical and decision-making coordination between two control center teams with two potentially maneuvering space vehicles.

  11. Meteorological and Back Trajectory Modeling for the Rocky Mountain Atmospheric Nitrogen and Sulfur Study II

    Directory of Open Access Journals (Sweden)

    Kristi A. Gebhart

    2014-01-01

    Full Text Available The Rocky Mountain Atmospheric Nitrogen and Sulfur (RoMANS II study with field operations during November 2008 through November 2009 was designed to evaluate the composition and sources of reactive nitrogen in Rocky Mountain National Park, Colorado, USA. As part of RoMANS II, a mesoscale meteorological model was utilized to provide input for back trajectory and chemical transport models. Evaluation of the model's ability to capture important transport patterns in this region of complex terrain is discussed. Previous source-receptor studies of nitrogen in this region are also reviewed. Finally, results of several back trajectory analyses for RoMANS II are presented. The trajectory mass balance (TrMB model, a receptor-based linear regression technique, was used to estimate mean source attributions of airborne ammonia concentrations during RoMANS II. Though ammonia concentrations are usually higher when there is transport from the east, the TrMB model estimates that, on average, areas to the west contribute a larger mean fraction of the ammonia. Possible reasons for this are discussed and include the greater frequency of westerly versus easterly winds, the possibility that ammonia is transported long distances as ammonium nitrate, and the difficulty of correctly modeling the transport winds in this area.

  12. Quasiclassical theory of coherent charge transport into multi-band superconductors

    NARCIS (Netherlands)

    Burmistrova, A.V.; Devyatov, I.A.; Golubov, Alexandre Avraamovitch; Yada, Keiji; Tanaka, Y.

    2014-01-01

    We formulate a quasiclassical theory of coherent charge transport in junctions involving multi-band iron-based superconductors (FeBSs), explicitly taking into account the complex excitation spectrum and unconventional nature of superconducting pairing in FeBSs. We perform calculations assuming intra

  13. Quasi-classical model of dynamic molecular structure and non-destructive wavepacket manipulation by ultrashort laser pulses

    CERN Document Server

    Bryan, W A; King, R B; Nemeth, G R A J; Greenwood, J B; Williams, I D; Newell, W R

    2010-01-01

    A quasi-classical model (QCM) of molecular dynamics in intense femtosecond laser fields has been developed, and applied to a study of the effect of an ultrashort `control' pulse on the vibrational motion of a deuterium molecular ion in its ground electronic state. A nonadiabatic treatment accounts for the initial ionization-induced vibrational population caused by an ultrashort `pump' pulse. In the QCM, the nuclei move classically on the molecular potential as it is distorted by the laser-induced Stark shift and transition dipole. The nuclei then adjust to the modified potential, non-destructively shifting the vibrational population and relative phase. This shift has been studied as a function of control pulse parameters. Excellent agreement is observed with predictions of time-dependent quantum simulations, lending confidence to the validity of the model and permitting new observations to be made. The applicability of the QCM to more complex multi-potential energy surface molecules (where a quantum treatment...

  14. Trajectories of PTSD risk and resilience in World Trade Center responders: an 8-year prospective cohort study.

    Science.gov (United States)

    Pietrzak, R H; Feder, A; Singh, R; Schechter, C B; Bromet, E J; Katz, C L; Reissman, D B; Ozbay, F; Sharma, V; Crane, M; Harrison, D; Herbert, R; Levin, S M; Luft, B J; Moline, J M; Stellman, J M; Udasin, I G; Landrigan, P J; Southwick, S M

    2014-01-01

    Longitudinal symptoms of post-traumatic stress disorder (PTSD) are often characterized by heterogeneous trajectories, which may have unique pre-, peri- and post-trauma risk and protective factors. To date, however, no study has evaluated the nature and determinants of predominant trajectories of PTSD symptoms in World Trade Center (WTC) responders. A total of 10835 WTC responders, including 4035 professional police responders and 6800 non-traditional responders (e.g. construction workers) who participated in the WTC Health Program (WTC-HP), were evaluated an average of 3, 6 and 8 years after the WTC attacks. Among police responders, longitudinal PTSD symptoms were best characterized by four classes, with the majority (77.8%) in a resistant/resilient trajectory and the remainder exhibiting chronic (5.3%), recovering (8.4%) or delayed-onset (8.5%) symptom trajectories. Among non-traditional responders, a six-class solution was optimal, with fewer responders in a resistant/resilient trajectory (58.0%) and the remainder exhibiting recovering (12.3%), severe chronic (9.5%), subsyndromal increasing (7.3%), delayed-onset (6.7%) and moderate chronic (6.2%) trajectories. Prior psychiatric history, Hispanic ethnicity, severity of WTC exposure and WTC-related medical conditions were most strongly associated with symptomatic trajectories of PTSD symptoms in both groups of responders, whereas greater education and family and work support while working at the WTC site were protective against several of these trajectories. Trajectories of PTSD symptoms in WTC responders are heterogeneous and associated uniquely with pre-, peri- and post-trauma risk and protective factors. Police responders were more likely than non-traditional responders to exhibit a resistant/resilient trajectory. These results underscore the importance of prevention, screening and treatment efforts that target high-risk disaster responders, particularly those with prior psychiatric history, high levels of

  15. Compressing spatio-temporal trajectories

    DEFF Research Database (Denmark)

    Gudmundsson, Joachim; Katajainen, Jyrki; Merrick, Damian

    2009-01-01

    A trajectory is a sequence of locations, each associated with a timestamp, describing the movement of a point. Trajectory data is becoming increasingly available and the size of recorded trajectories is getting larger. In this paper we study the problem of compressing planar trajectories such tha...

  16. Is Project Management Still an Accidental Profession? A Qualitative Study of Career Trajectory

    Directory of Open Access Journals (Sweden)

    Tracey M. Richardson

    2015-02-01

    Full Text Available In this study, the authors used qualitative techniques to look for reoccurring themes related to 87 project managers’ responses to interview questions associated with entry into the field of project management and career progression. The study found that despite the efforts of higher education, professional associations, and their professional development and certifications, the project management remains a destination by accident. Professional project managers do not intend to be project managers but “fall into” the profession. This study provides a conceptual framework for project manager career trajectory that has implications for project management training and mentoring and contributes to the growing literature on the accidental profession.

  17. Employment Trajectories After Spinal Cord Injury : Results From a 5-Year Prospective Cohort Study

    NARCIS (Netherlands)

    Ferdiana, Astri; Post, Marcel W.; Hoekstra, Trynke; van der Woude, Luccas H.; van der Klink, Jac J.; Bultmann, Ute

    2014-01-01

    Objectives: To identify different employment trajectories in individuals with spinal cord injury (SCI) after discharge from initial rehabilitation and to determine predictors of different trajectories from demographic, injury, functional, and psychological characteristics. Design: Prospective cohort

  18. The enduring effect of education-socioeconomic differences in disability trajectories from age 85 years in the Newcastle 85+ Study

    Science.gov (United States)

    Kingston, Andrew; Davies, Karen; Collerton, Joanna; Robinson, Louise; Duncan, Rachel; Kirkwood, Thomas B.L.; Jagger, Carol

    2015-01-01

    Objective Little is known about disability progression in very old age despite this being vital for care planning. We investigate whether distinct trajectories of disability are evident from age 85 to 90 and their association with socio-economic status (SES). Methods The Newcastle 85+ Study recruited people born in 1921 through participating general practices in Newcastle and North Tyneside. Participants underwent a health assessment (HA) at baseline, 18, 36 and 60 months and a GP record review (GPRR) at baseline, 36 and 60 months. Disability was measured via difficulty in 17 Activities of Daily Living. Trajectory identification was assessed by gender stratified, mortality adjusted, group-based trajectory modelling (GBTM) and the impact of life-course SES (level of education; occupational class; deprivation) on trajectory membership evaluated (adjusting for confounding variables). Results 851 participants agreed to HA and GPRR, 840 (98.7%) with complete disability data. Four distinct trajectories were evident for both sexes. A disability-free trajectory between age 85 and 90 was identified in men only (9% of the sample). The most disabled trajectories had severe disability at age 85 progressing to profound disability by age 90. After adjusting for confounders education remained significant; men and women with most education being less likely to be in the most disabled trajectory (Men: OR = 0.80, 95% CI 0.65–0.98; women: OR = 0.59, 95% CI 0.42–0.83). Conclusion Distinct disability trajectories are evident in the very old and these are influenced by education, suggesting SES disadvantages cumulate throughout the life-course to create health and mortality inequalities later. PMID:25747850

  19. Quasiclassical methods for spin-charge coupled dynamics in low-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Corini, Cosimo

    2009-06-12

    Spintronics is a new field of study whose broad aim is the manipulation of the spin degrees of freedom in solid state systems. One of its main goals is the realization of devices capable of exploiting, besides the charge, the carriers' - and possibly the nuclei's - spin. The presence of spin-orbit coupling in a system enables the spin and charge degrees of freedom to ''communicate'', a favorable situation if one is to realize such devices. More importantly, it offers the opportunity of doing so by relying solely on electric fields, whereas magnetic fields are otherwise required. Eminent examples of versatile systems with built-in and variously tunable spin-orbit interaction are two-dimensional electron - or hole - gases. The study of spin-charge coupled dynamics in such a context faces a large number of open questions, both of the fundamental and of the more practical type. To tackle the problem we rely on the quasiclassical formalism. This is an approximate quantum-field theoretical formulation with a solid microscopic foundation, perfectly suited for describing phenomena at the mesoscopic scale, and bearing a resemblance to standard Boltzmann theory which makes for physical transparency. Originally born to deal with transport in electron-phonon systems, we first generalize it to the case in which spin-orbit coupling is present, and then move on to apply it to specific situations and phenomena. Among these, to the description of the spin Hall effect and of voltage induced spin polarizations in two-dimensional electron gases under a variety of conditions - stationary or time-dependent, in the presence of magnetic and non-magnetic disorder, in the bulk or in confined geometries -, and to the problem of spin relaxation in narrow wires. (orig.)

  20. Dynamics and Kinetics Study of "In-Water" Chemical Reactions by Enhanced Sampling of Reactive Trajectories.

    Science.gov (United States)

    Zhang, Jun; Yang, Y Isaac; Yang, Lijiang; Gao, Yi Qin

    2015-11-12

    High potential energy barriers and engagement of solvent coordinates set challenges for in silico studies of chemical reactions, and one is quite commonly limited to study reactions along predefined reaction coordinate(s). A systematic protocol, QM/MM MD simulations using enhanced sampling of reactive trajectories (ESoRT), is established to quantitatively study chemical transitions in complex systems. A number of trajectories for Claisen rearrangement in water and toluene were collected and analyzed, respectively. Evidence was found that the bond making and breaking during this reaction are concerted processes in solutions, preferentially through a chairlike configuration. Water plays an important dynamic role that helps stabilize the transition sate, and the dipole-dipole interaction between water and the solute also lowers the transition barrier. The calculated rate coefficient is consistent with the experimental measurement. Compared with water, the reaction pathway in toluene is "narrower" and the reaction rate is slower by almost three orders of magnitude due to the absence of proper interactions to stabilize the transition state. This study suggests that the "in-water" nature of the Claisen rearrangement in aqueous solution influences its thermodynamics, kinetics, as well as dynamics.

  1. Outcomes of childhood conduct problem trajectories in early adulthood: findings from the ALSPAC study.

    Science.gov (United States)

    Kretschmer, Tina; Hickman, Matthew; Doerner, Rita; Emond, Alan; Lewis, Glyn; Macleod, John; Maughan, Barbara; Munafò, Marcus R; Heron, Jon

    2014-07-01

    Although conduct problems in childhood are stably associated with problem outcomes, not every child who presents with conduct problems is at risk. This study extends previous studies by testing whether childhood conduct problem trajectories are predictive of a wide range of other health and behavior problems in early adulthood using a general population sample. Based on 7,218 individuals from the Avon longitudinal study of parents and children, a three-step approach was used to model childhood conduct problem development and identify differences in early adult health and behavior problems. Childhood conduct problems were assessed on six occasions between age 4 and 13 and health and behavior outcomes were measured at age 18. Individuals who displayed early-onset persistent conduct problems throughout childhood were at greater risk for almost all forms of later problems. Individuals on the adolescent-onset conduct problem path consumed more tobacco and illegal drugs and engaged more often in risky sexual behavior than individuals without childhood conduct problems. Levels of health and behavior problems for individuals on the childhood-limited path were in between those for stable low and stable high trajectories. Childhood conduct problems are pervasive and substantially affect adjustment in early adulthood both in at-risk samples as shown in previous studies, but also in a general population sample. Knowing a child's developmental course can help to evaluate the risk for later maladjustment and be indicative of the need for early intervention.

  2. Methods for evaluating physical processes in strong external fields at e+e- colliders: Furry picture and quasi-classical approach

    CERN Document Server

    Porto, Stefano; Moortgat-Pick, Gudrid

    2013-01-01

    Future linear colliders designs, ILC and CLIC, are expected to be powerful machines for the discovery of Physics Beyond the Standard Model and subsequent precision studies. However, due to the intense beams (high luminosity, high energy), strong electromagnetic fields occur in the beam-beam interaction region. In the context of precision high energy physics, the presence of such strong fields may yield sensitive corrections to the observed electron-positron processes. The Furry picture of quantum states gives a conceptually simple tool to treat physics processes in an external field. A generalization of the quasi-classical operator method (QOM) as an approximation is considered too.

  3. Methods for evaluating physical processes in strong external fields at e{sup +}e{sup -} colliders. Furry picture and quasi-classical approach

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Stefano [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Hartin, Anthony [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Moortgat-Pick, Gudrid [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-04-15

    Future linear colliders designs, ILC and CLIC, are expected to be powerful machines for the discovery of Physics Beyond the Standard Model and subsequent precision studies. However, due to the intense beams (high luminosity, high energy), strong electromagnetic fields occur in the beam-beam interaction region. In the context of precision high energy physics, the presence of such strong fields may yield sensitive corrections to the observed electron-positron processes. The Furry picture of quantum states gives a conceptually simple tool to treat physics processes in an external field. A generalization of the quasi-classical operator method (QOM) as an approximation is considered too.

  4. Palliative care needs at different phases in the illness trajectory: a survey study in patients with cancer.

    Science.gov (United States)

    Beernaert, K; Pardon, K; Van den Block, L; Devroey, D; De Laat, M; Geboes, K; Surmont, V; Deliens, L; Cohen, J

    2016-07-01

    Despite the growing consensus on the benefits of initiating palliative care early in the disease trajectory, it remains unclear at what point palliative care needs emerge. This study investigates quality of life and unmet palliative care needs at three phases in the cancer trajectory, curative, life-prolonging and most advanced (prognosis care needs within the domains of palliative care. We used European reference values of the EORTC QLQ-C30 to compare the mean scores with a norm group. The groups further on in the cancer trajectory reported statistically and clinically poorer functioning compared with earlier phases, also when controlled for the effects of sex, age or type of cancer. Higher symptom burdens for fatigue, pain, dyspnoea and appetite loss were found in groups further into the trajectory, p care needs of patients from diagnosis onwards.

  5. Developmental Trajectories of Disordered Eating from Early Adolescence to Young Adulthood: A Longitudinal Study

    Science.gov (United States)

    Slane, Jennifer D.; Klump, Kelly L.; McGue, Matthew; Iacono, William G.

    2014-01-01

    Objective Research examining changes in eating disorder symptoms across adolescence suggests an increase in disordered eating from early to late adolescence. However, relevant studies have largely been cross-sectional in nature and most have not examined the changes in the attitudinal symptoms of eating disorders (e.g., weight concerns). This longitudinal study aimed to address gaps in the available data by examining the developmental trajectories of disordered eating in females from preadolescence into young adulthood. Method Participants were 745 same-sex female twins from the Minnesota Twin Family Study. Disordered eating was assessed using the Total Score, Body Dissatisfaction subscale, Weight Preoccupation subscale, and a combined Binge Eating and Compensatory Behavior subscale from the Minnesota Eating Behavior Survey assessed at the ages of 11, 14, 18, 21, and 25. Several latent growth models were fit to the data to identify the trajectory that most accurately captures the changes in disordered eating symptoms from 11 to 25 years. Results The best-fitting models for overall levels of disordered eating, body dissatisfaction, and weight preoccupation showed an increase in from 11 through 25 years. In contrast, bulimic behaviors increased to age of 18 and then stabilized to age of 25. Discussion The findings expanded upon extant research by investigating longitudinal, symptom specific, within-person changes and showing an increase in cognitive symptoms into young adulthood and the stability of disordered eating behaviors past late adolescence. PMID:24995824

  6. Quasiclassical Green function in an external field and small-angle scattering

    CERN Document Server

    Lee, R N; Strakhovenko, V M

    1999-01-01

    The quasiclassical Green functions of the Dirac and Klein-Gordon equations in the external electric field are obtained with the first correction taken into account. The relevant potential is assumed to be localized, while its spherical symmetry is not required. Using these Green functions, the corresponding wave functions are found in the approximation similar to the Furry-Sommerfeld-Maue approximation. It is shown that the quasiclassical Green function does not coincide with the Green function obtained in the eikonal approximation and has a wider region of applicability. It is illustrated by the calculation of the small-angle scattering amplitude for a charged particle and the forward photon scattering amplitude. For charged particles, the first correction to the scattering amplitude in the non-spherically symmetric potential is found. This correction is proportional to the scattering angle. The real part of the amplitude of forward photon scattering in a screened Coulomb potential is obtained.

  7. Childhood Anxiety Trajectories and Adolescent Disordered Eating: Findings from the NICHD Study of Early Child Care and Youth Development

    Science.gov (United States)

    Zerwas, Stephanie; Von Holle, Ann; Watson, Hunna; Gottfredson, Nisha; Bulik, Cynthia M.

    2015-01-01

    Objective The goal of the present paper was to examine whether childhood anxiety trajectories predict eating psychopathology. We predicted that girls with trajectories of increasing anxiety across childhood would have significantly greater risk of disordered eating in adolescence in comparison to girls with stable or decreasing trajectories of anxiety over childhood. Method Data were collected as part of the prospective longitudinal NICHD Study of Early Child Care and Youth Development (N=450 girls). Childhood anxiety was assessed yearly (54 months through 6th grade) via maternal report on the Child Behavior Checklist. Disordered eating behaviors were assessed at age 15 via adolescent self-report on the Eating Attitudes Test (EAT-26). We conducted latent growth mixture modeling to define girls’ childhood anxiety trajectories. Maternal sensitivity, maternal postpartum depression, maternal anxiety, and child temperament were included as predictors of trajectory membership. Results The best fitting model included three trajectories of childhood anxiety, the low-decreasing class (22.9% of girls), the high-increasing class (35.4%), and the high-decreasing class (41.6%). Mothers with more symptoms of depression and separation anxiety had girls who were significantly more likely to belong to the high-increasing anxiety trajectory. There were no significant differences in adolescent disordered eating for girls across the three childhood anxiety trajectories. Conclusions Childhood anxiety, as captured by maternal report, may not be the most robust predictor of adolescent disordered eating and may be of limited utility for prevention programs that aim to identify children in the community at greatest risk for disordered eating. PMID:24938214

  8. Modeling cognitive trajectories within longitudinal studies: a focus on older adults.

    Science.gov (United States)

    Steinerman, Joshua R; Hall, Charles B; Sliwinski, Martin J; Lipton, Richard B

    2010-10-01

    The natural history of life span cognitive performance and its late-life determinants have been studied from an array of perspectives. Significant insights come from psychological disciplines, including cognitive, developmental, and neuropsychology, as well as from medical specialties, such as geriatrics, neurology, psychiatry, neuroradiology, and neuropathology, that contribute to the growing interdisciplinary scientific field: cognitive neuroscience of aging. This survey of longitudinal studies of aging suggests that disease-oriented investigations commonly do not adequately consider normative cognitive changes, whereas developmental studies do not sufficiently measure and model nonnormative cognitive aging. This article argues for an integrative perspective that considers both of these influences on cognitive trajectories and presents a series of methodological concerns that have not been addressed comprehensively. Interdisciplinary methods from longitudinal observational studies should be leveraged to enable translational interventions to promote brain longevity.

  9. [Trajectories of aging in a sample of elderly people: a longitudinal study].

    Science.gov (United States)

    Navarro-González, Elena; Calero, María Dolores; Becerra-Reina, Dolores

    2015-01-01

    The present study analyzes variables associated with different trajectories of aging, and the level of cognitive functioning in a sample of older adults. Although this work is part of a broader investigation where initially 141 people were assessed, this paper only discusses the cognitive functioning and cognitive development of 64 older people who have been followed up four years after the initial assessment, with a mean age of 83.84 years (age range 65 to 99 years). In the initial assessment all the participants were assessed with a psychological battery that included the MEC, the verbal fluency task FVS, a sustained attention task, a working memory test, a Quality of Life Questionnaire, a scale of dependency, and the AVLT-Learning Potential test. In the follow up assessment, participants have been assessed with the MEC, the verbal fluency task FVS, and the verbal memory test AVLT-PA. the results show relatively stable trajectories of aging and that the variables that better predict cognitive evolution of the elderly are working memory and post-test score in the AVLT-LP. Despite the time lapse between the two assessments and the age of the participants, older adults have remained relatively stable in their cognitive functioning, which in part contradicts the idea that--especially after 80 years--a general decline of cognitive functioning occurs in old age. Copyright © 2014 SEGG. Published by Elsevier Espana. All rights reserved.

  10. Quantum and quasi-classical collisional dynamics of O2-Ar at high temperatures

    Science.gov (United States)

    Ulusoy, Inga S.; Andrienko, Daniil A.; Boyd, Iain D.; Hernandez, Rigoberto

    2016-06-01

    A hypersonic vehicle traveling at a high speed disrupts the distribution of internal states in the ambient flow and introduces a nonequilibrium distribution in the post-shock conditions. We investigate the vibrational relaxation in diatom-atom collisions in the range of temperatures between 1000 and 10 000 K by comparing results of extensive fully quantum-mechanical and quasi-classical simulations with available experimental data. The present paper simulates the interaction of molecular oxygen with argon as the first step in developing the aerothermodynamics models based on first principles. We devise a routine to standardize such calculations also for other scattering systems. Our results demonstrate very good agreement of vibrational relaxation time, derived from quantum-mechanical calculations with the experimental measurements conducted in shock tube facilities. At the same time, the quasi-classical simulations fail to accurately predict rates of vibrationally inelastic transitions at temperatures lower than 3000 K. This observation and the computational cost of adopted methods suggest that the next generation of high fidelity thermochemical models should be a combination of quantum and quasi-classical approaches.

  11. Gender-Specific Developmental Trajectories of Anxiety during Adolescence : Determinants and Outcomes. The TRAILS Study

    NARCIS (Netherlands)

    Legerstee, Jeroen S; Verhulst, Frank C; Robbers, Sylvana C C; Ormel, Johan; Oldehinkel, Albertine J; van Oort, Floor V A

    OBJECTIVE: To identify developmental trajectories of anxiety symptoms for adolescent girls and boys. Trajectories were compared with regard to early-adolescent risk factors and psychiatric outcomes during adolescence and in young adulthood. METHOD: A community sample of 2,230 adolescents was

  12. Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Bineyam Taye

    2016-09-01

    Conclusions: These findings add to the growing body of evidence supporting that H. pylori infection is inversely associated with childhood growth trajectory, after controlling for a range of factors associated with reduced growth and H. pylori status. Further follow-up will be important to confirm possible catch-up in height trajectory among H. pylori-infected children as they grow older.

  13. Developmental trajectories of associative memory from childhood to adulthood: a behavioral and neuroimaging study.

    Science.gov (United States)

    Guillery-Girard, Bérengère; Martins, Sylvie; Deshayes, Sebastien; Hertz-Pannier, Lucie; Chiron, Catherine; Jambaqué, Isabelle; Landeau, Brigitte; Clochon, Patrice; Chételat, Gaël; Eustache, Francis

    2013-01-01

    Episodic memory refers to the capacity to bind multimodal memories to constitute a unique personal event. Most developmental studies on episodic memory focused on one specific component, i.e., the core factual information. The present study examines the relevance of a novel episodic paradigm to assess its developmental trajectories in a more comprehensive way according to the type of association (item-feature, item-location, and item-sequence associations) with measures of both objective and subjective recollection. We conducted a behavioral study aimed at testing the effects of age in a large sample of 160 children, adolescents, and young adults (6-23 years old). We confronted the behavioral data to the neural correlates in a subgroup of 30 children using voxel-based morphometry. Behavioral data outlined differential developmental trajectories according to the type of association, with a continuous increase of factual associative memory efficiency until 10 years, a linear increase of performance in spatial associative memory that pursues until early adulthood and an abrupt increase in temporal associative memory efficiency between 9 and 10. Regarding recollection, measures showed a more pronounced enhancement from 9 to 10 years. Hence, behavioral data highlight a peculiar period in late childhood (8-10 years old) crucial for the developmental time course of episodic memory. Regarding structural data, we found that the improvement of associative memory efficiency was related to a decrease in gray matter volume in a large cerebral network including the dorsolateral and ventrolateral prefrontal cortex (and superior and anterior temporal regions), and the hippocampus bilaterally. These data suggest that multimodal integration would probably be related to the maturation of temporal regions and modulated by a fronto-parietal network. Besides, our findings emphasize the relevance of the present paradigm to assess episodic memory especially in the clinical setting.

  14. Developmental trajectories of associative memory from childhood to adulthood: a behavioral and neuroimaging study

    Directory of Open Access Journals (Sweden)

    Berengere eGuillery-Girard

    2013-09-01

    Full Text Available Episodic memory refers to the capacity to bind multimodal memories to constitute a unique personal event. Most developmental studies on episodic memory focused on one specific component, i.e. the core factual information. The present study examines the relevance of a novel episodic paradigm to assess its developmental trajectories in a more comprehensive way according to the type of association (item-feature, item-location and item-sequence associations with measures of both objective and subjective recollection. We conducted a behavioral study aimed at testing the effects of age in a large sample of 160 children, adolescents and young adults (6 to 23 years old. We confronted the behavioral data to the neural correlates in a subgroup of 30 children using voxel-based morphometry. Behavioral data outlined differential developmental trajectories according to the type of association, with a continuous increase of factual associative memory efficiency until 10 years, a linear increase of performance in spatial associative memory that pursues until early adulthood and an abrupt increase in temporal associative memory efficiency between 9 and 10. Regarding recollection, measures showed a more pronounced enhancement from 9 to 10 years. Hence, behavioral data highlight a peculiar period in late childhood (8 to 10 years old crucial for the developmental time course of episodic memory. Regarding structural data, we found that the improvement of associative memory efficiency was related to a decrease in gray matter volume in a large cerebral network including the dorsolateral and ventrolateral prefrontal cortex (and superior and anterior temporal regions and the hippocampus bilaterally. These data suggest that multimodal integration would probably be related to the maturation of temporal regions and modulated by a fronto-parietal network. Besides, our findings emphasize the relevance of the present paradigm to assess episodic memory especially in the

  15. Anxiety trajectories and identity development in adolescence: a five-wave longitudinal study.

    Science.gov (United States)

    Crocetti, Elisabetta; Klimstra, Theo; Keijsers, Loes; Hale, William W; Meeus, Wim

    2009-07-01

    The aim of this five-wave longitudinal study was to investigate the relationship between anxiety and adolescent identity development. Participants were 1,313 adolescents who annually completed measures of anxiety and identity. Growth Mixture Modeling (GMM) analyses demonstrated that the adolescent population was best typified by two latent growth trajectory classes: a low anxiety class (n = 1,199) characterized by a low initial level of anxiety that decreased over time and a high anxiety class (n = 114) characterized by a higher initial level of anxiety that increased over time. To answer our research question, we tested a model in which the anxiety classes predicted initial levels and rates of change of three identity dimensions: commitment, in-depth exploration, and reconsideration of commitment. Findings indicated that the high anxiety adolescents displayed a more troublesome identity development than their low anxiety peers, since their commitments became weaker with age, and they reconsidered them intensively.

  16. Parenting and Trajectories of Children’s Maladaptive Behaviors: A 12-year Prospective Community Study

    Science.gov (United States)

    Luyckx, Koen; Tildesley, Elizabeth A.; Soenens, Bart; Andrews, Judy A.; Hampson, Sarah E.; Peterson, Missy; Duriez, Bart

    2011-01-01

    This study investigated how parenting accounted for inter-individual differences in developmental trajectories of different child behaviors across childhood and adolescence. In a cohort sequential community sample of 1,049 children, latent class growth analysis was applied to three parent-reported dimensions (monitoring, positive parenting, inconsistent discipline) across 12 annual assessments (ages 6–18). Four longitudinal parenting styles (authoritative, authoritarian, indulgent, uninvolved) were differentiated on the basis of levels and rates of change in the constituent parenting dimensions. Multi-group analyses demonstrated that these parenting styles were differentially related to changes in parent- and child-reported measures of children’s alcohol and cigarette use, antisocial behavior, and internalizing symptoms, with the authoritative parenting class being related to the most optimal long-term development. Practical implications and future research suggestions are discussed. PMID:21534057

  17. Regression, developmental trajectory and associated problems in disorders in the autism spectrum: the SNAP study.

    Science.gov (United States)

    Baird, Gillian; Charman, Tony; Pickles, Andrew; Chandler, Susie; Loucas, Tom; Meldrum, David; Carcani-Rathwell, Iris; Serkana, Devanitha; Simonoff, Emily

    2008-11-01

    We report rates of regression and associated findings in a population derived group of 255 children aged 9-14 years, participating in a prevalence study of autism spectrum disorders (ASD); 53 with narrowly defined autism, 105 with broader ASD and 97 with non-ASD neurodevelopmental problems, drawn from those with special educational needs within a population of 56,946 children. Language regression was reported in 30% with narrowly defined autism, 8% with broader ASD and less than 3% with developmental problems without ASD. A smaller group of children were identified who underwent a less clear setback. Regression was associated with higher rates of autistic symptoms and a deviation in developmental trajectory. Regression was not associated with epilepsy or gastrointestinal problems.

  18. Cultural Orientation Trajectories and Substance Use: Findings From a Longitudinal Study of Mexican-Origin Youth.

    Science.gov (United States)

    Cruz, Rick A; King, Kevin M; Cauce, Ana M; Conger, Rand D; Robins, Richard W

    2017-03-01

    Cultural adaptation may influence Latino youth substance use (SU) development, yet few longitudinal studies have examined cultural change over time and adolescent SU outcomes. Using longitudinal data collected annually across ages 10-16 from 674 Mexican-origin youth (50% female), the authors characterized cultural adaptation patterns for language use (English and Spanish use), values (American values and familism values), and identity (ethnic pride), and examined whether these cultural adaptation patterns were associated with differential SU risk. Youth with increasing bilingualism and high/stable family values had lower SU risk compared to youth who primarily spoke English and endorsed decreasing family values, respectively. Ethnic pride trajectories were not associated with SU. Findings highlight the importance of considering cultural change related to Latino youth SU.

  19. Determining leaf trajectories for dynamic multileaf collimators with consideration of marker visibility: an algorithm study.

    Science.gov (United States)

    Zhao, Bo; Dai, Jianrong

    2014-09-01

    The purpose of this study was to develop a leaf-setting algorithm for Dynamic Multileaf Collimator-Intensity-Modulated Radiation Therapy (DMLC-IMRT) for optimal marker visibility. Here, a leaf-setting algorithm (called a Delta algorithm) was developed with the objective of maximizing marker visibility so as to improve the tracking effectiveness of fiducial markers during treatment delivery. The initial leaf trajectories were generated using a typical leaf-setting algorithm, then the leaf trajectories were adjusted by Delta algorithm operations (analytical computations and a series of matrix calculations) to achieve the optimal solution. The performance of the Delta algorithm was evaluated with six test fields (with randomly generated intensity profiles) and 15 clinical fields from IMRT plans of three prostate cancer patients. Compared with the initial solution, the Delta algorithm kept the total delivered intensities (TDIs) constant (without increasing the beam delivery time), but improved marker visibility (the percentage ratio of marker visibility time to beam delivery time). For the artificial fields (with three markers), marker visibility increased from 68.00-72.00% for a small field (5 × 5), from 38.46-43.59% for a medium field (10 × 10), and from 28.57-37.14% for a large field (20 × 20). For the 15 clinical fields, marker visibility increased 6-30% for eight fields and > 50% for two fields but did not change for five fields. A Delta algorithm was proposed to maximize marker visibility for DMLC-IMRT without increasing beam delivery time, and this will provide theoretical fundamentals for future studies of 4D DMLC tracking radiotherapy. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  20. TRAJECTORIES OF DEPRESSIVE EPISODES AND HYPERTENSION OVER 24 YEARS: THE WHITEHALL II PROSPECTIVE COHORT STUDY

    Science.gov (United States)

    Nabi, Hermann; Chastang, Jean-François; Lefèvre, Thomas; Dugravot, Aline; Melchior, Maria; Marmot, Michael G.; Shipley, Martin J.; Kivimäki, Mika; Singh-Manoux, Archana

    2011-01-01

    Prospective data on depressive symptoms and blood pressure (BP) are scarce, and the impact of age on this association is poorly understood. The present study examines longitudinal trajectories of depressive episodes and the probability of hypertension associated with these trajectories over time. Participants were 6,889 men and 3,413 women London based civil servants, aged 35–55 years at baseline, followed for 24 years between 1985 and 2009. Depressive episode (defined as scoring 4 or more on the General Health Questionnaire-Depression subscale or using prescribed antidepressant medication) and hypertension (systolic/diastolic blood pressure ≥ 140/90 mm Hg or use of antihypertensive medication) were assessed concurrently at five medical examinations. In the fully adjusted longitudinal logistic regression analyses based on Generalized-Estimating-Equations using age as the time scale, participants in the “increasing depression” group had a 24% (p<0.05) lower risk of hypertension at ages 35–39, compared to those in the “low/transient depression” group. However, there was a faster age-related increase in hypertension in the “increasing depression” group, corresponding to a 7% (p<0.01) greater increase in the odds of hypertension for every each five-year increase in age. A higher risk of hypertension in the first group of participants was not evident before age 55. A similar pattern of association was observed in men and women although it was stronger in men. This study suggests that the risk of hypertension increases with repeated experience of depressive episodes over time and becomes evident in later adulthood. PMID:21339474

  1. Aircraft Trajectory Optimization Using Parametric Optimization Theory

    OpenAIRE

    Valenzuela Romero, Alfonso

    2012-01-01

    In this thesis, a study of the optimization of aircraft trajectories using parametric optimization theory is presented. To that end, an approach based on the use of predefined trajectory patterns and parametric optimization is proposed. The trajectory pat

  2. Trajectories of Mental Health over 16 Years amongst Young Adult Women: The Australian Longitudinal Study on Women's Health

    Science.gov (United States)

    Holden, Libby; Ware, Robert S.; Lee, Christina

    2016-01-01

    This article used data from 5,171 young women participating in the Australian Longitudinal Study on Women's Health, a nationally representative longitudinal cohort study, to identify longitudinal trajectory patterns of mental health across 6 surveys over 16 years of early adulthood, from age 18-23 to age 34-39. In addition, we identified both…

  3. Girls' Tobacco and Alcohol Use during Early Adolescence: Prediction from Trajectories of Depressive Symptoms across Two Studies

    Science.gov (United States)

    Leve, Leslie D.; Harold, Gordon T.; Van Ryzin, Mark J.; Elam, Kit; Chamberlain, Patricia

    2012-01-01

    Associations between trajectories of depressive symptoms and subsequent tobacco and alcohol use were examined in two samples of girls assessed at age 11.5 (T1), 12.5 (T2), and 13.5 (T3). Two samples were examined to ascertain if there was generalizability of processes across risk levels and cultures. Study 1 comprised a United States-based sample…

  4. Mixed time-dependent density-functional theory/classical trajectory surface hopping study of oxirane photochemistry

    NARCIS (Netherlands)

    Tapavicza, Enrico; Tavernelli, Ivano; Rothlisberger, Ursula; Filippi, Claudia; Casida, Mark E.

    2008-01-01

    We present a mixed time-dependent density-functional theory (TDDFT)/classical trajectory surface hopping (SH) study of the photochemical ring opening in oxirane. Previous preparatory work limited to the symmetric CC ring-opening pathways of oxirane concluded that the Tamm-Dancoff approximation (TDA)

  5. Adding Learning Resources: A Study of Two Toddlers' Modes and Trajectories of Participation in Early Childhood Education

    Science.gov (United States)

    Kultti, Anne

    2015-01-01

    This study focuses on the nature of children's participation in an Australian early childhood context in which their second language is used. The aim is to create knowledge of toddlers' modes and trajectories of participation. Empirical data documenting the participation of two toddlers were gathered through video observations of everyday…

  6. Trajectories and Determinants of Alcohol Use among LGB Young Adults and Their Heterosexual Peers: Results from a Prospective Study

    Science.gov (United States)

    Hatzenbuehler, Mark L.; Corbin, William R.; Fromme, Kim

    2008-01-01

    Lesbians, gays, and bisexuals (LGBs) are at increased risk for alcohol use during young adulthood, but the mechanisms remain inadequately understood. The aim of the present study was to examine the trajectories and determinants of alcohol use among LGB young adults who were sampled prospectively. The sample included 111 LGB individuals (47 women…

  7. Age-related brain trajectories in schizophrenia: a systematic review of structural MRI studies.

    Science.gov (United States)

    Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Piras, Federica; Caltagirone, Carlo; Spalletta, Gianfranco

    2013-11-30

    Using the Pubmed database, we performed a detailed literature search for structural magnetic resonance imaging studies on patients with schizophrenia, investigating the relationship between macroscopic and microscopic structural parameters and age, to delineate an age-related trajectory. Twenty-six studies were considered for the review, from January 2000 to June 2012. Research results are heterogeneous because of the multifactorial features of schizophrenia and the multiplicity of the methodological approaches adopted. Some areas, within the amygdala-hippocampus complex, which are affected early in life by schizophrenia, age in a physiological way. Other regions, such as the superior temporal gyrus, appear already impaired at the onset of symptoms, undergo a worsening in the acute phase but later stabilize, progressing physiologically over years. Finally, there are regions, such as the uncinate fasciculus, which are not altered early in life, but are affected around the onset of schizophrenia, with their impairment continuously worsening over time. Further extensive longitudinal studies are needed to understand the timing and the possible degenerative characteristics of structural impairment associated with schizophrenia.

  8. A study on a robot arm driven by three-dimensional trajectories predicted from non-invasive neural signals.

    Science.gov (United States)

    Kim, Yoon Jae; Park, Sung Woo; Yeom, Hong Gi; Bang, Moon Suk; Kim, June Sic; Chung, Chun Kee; Kim, Sungwan

    2015-08-20

    A brain-machine interface (BMI) should be able to help people with disabilities by replacing their lost motor functions. To replace lost functions, robot arms have been developed that are controlled by invasive neural signals. Although invasive neural signals have a high spatial resolution, non-invasive neural signals are valuable because they provide an interface without surgery. Thus, various researchers have developed robot arms driven by non-invasive neural signals. However, robot arm control based on the imagined trajectory of a human hand can be more intuitive for patients. In this study, therefore, an integrated robot arm-gripper system (IRAGS) that is driven by three-dimensional (3D) hand trajectories predicted from non-invasive neural signals was developed and verified. The IRAGS was developed by integrating a six-degree of freedom robot arm and adaptive robot gripper. The system was used to perform reaching and grasping motions for verification. The non-invasive neural signals, magnetoencephalography (MEG) and electroencephalography (EEG), were obtained to control the system. The 3D trajectories were predicted by multiple linear regressions. A target sphere was placed at the terminal point of the real trajectories, and the system was commanded to grasp the target at the terminal point of the predicted trajectories. The average correlation coefficient between the predicted and real trajectories in the MEG case was [Formula: see text] ([Formula: see text]). In the EEG case, it was [Formula: see text] ([Formula: see text]). The success rates in grasping the target plastic sphere were 18.75 and 7.50 % with MEG and EEG, respectively. The success rates of touching the target were 52.50 and 58.75 % respectively. A robot arm driven by 3D trajectories predicted from non-invasive neural signals was implemented, and reaching and grasping motions were performed. In most cases, the robot closely approached the target, but the success rate was not very high because

  9. The Polarization of Radiation in Single Cristals in the Quasiclassical Approach

    CERN Document Server

    Darbinian, S M

    1999-01-01

    The radiation emission spectra of polarized photons emitted from charged particles in single oriented crystals are obtained in Bayer-Katkov quasiclassical approach. The results of numerical calculations are presented in the region of small angles of incidence for which the coherent theory fails but magnetic bremsstrahlung region isn't yet achieved. The spectral distribution of linear polarization degree repeats, in general, the form of the intensity distribution. At sufficiently small angles, in the case of planar orientation of crystal, there is a wide maximum of essential linear polarization at low frequencies.

  10. Quasiclassical description of multi-band superconductors with two order parameters

    Energy Technology Data Exchange (ETDEWEB)

    Moor, Andreas

    2014-05-19

    This Thesis deals with multi-band superconductors with two order parameters, i.e., the superconductivity and the spin-density wave, also touching on one-band superconductors with a charge-density wave, as well as with only the superconducting order parameter. Quasiclassical description of suchlike structures is developed and applied to investigation of various effects, inter alia, the Josephson and the proximity effects, the Knight shift, the Larkin-Ovchinnikov-Fulde-Ferrell-like state, and the interplay of the order parameters in coexistence regime. The applicability of the developed approach to pnictides is discussed.

  11. The role of plant properties in arm trajectory formation: a neural network study.

    Science.gov (United States)

    Massone, L E; Myers, J D

    1996-01-01

    In this paper, we first introduce a neural network model of a planar, six-muscle, redundant arm whose structure and operation principles were inspired by those of the human arm. We developed the model with a motor-learning framework in mind, i.e., with the long-term goal of incorporating it in a parallel distributed learning scheme for the arm controller. We then demonstrate the response of the model to various patterns of activation of the arm muscles in order to study the relative role of control strategies and plant properties in trajectory formation. The results of our simulations emphasize the role of the intrinsic properties of the plant in generating movements with anthropomorphic qualities such as smoothness and unimodal velocity profiles, and demonstrate that the task of an eventual controller for the arm could be simply that of programming the amplitudes and durations of steps of neural input without considering additional motor details. Our findings are relevant to the design of artificial arms and, with some caveats, to the study of the brain strategies in the arm motor system.

  12. Quantum trajectories

    CERN Document Server

    Chattaraj, Pratim Kumar

    2010-01-01

    The application of quantum mechanics to many-particle systems has been an active area of research in recent years as researchers have looked for ways to tackle difficult problems in this area. The quantum trajectory method provides an efficient computational technique for solving both stationary and time-evolving states, encompassing a large area of quantum mechanics. Quantum Trajectories brings the expertise of an international panel of experts who focus on the epistemological significance of quantum mechanics through the quantum theory of motion.Emphasizing a classical interpretation of quan

  13. Periconception Maternal Folate Status and Human Embryonic Cerebellum Growth Trajectories: The Rotterdam Predict Study.

    Directory of Open Access Journals (Sweden)

    Irene V Koning

    Full Text Available We aimed to investigate whether periconceptional maternal folate status affects human embryonic cerebellar size and growth trajectories. In a prospective periconceptional cohort participants filled out questionnaires and received weekly transvaginal 3D-ultrasounds between 7+0 and 12+6 weeks gestational age (GA. Viable non-malformed singleton pregnancies were selected for cerebellar measurements; transcerebellar diameter, (TCD, left and right cerebellar diameters (LCD, RCD. Linear mixed models were performed to estimate associations between questionnaire data on the timing of maternal folic acid supplement initiation and longitudinal cerebellar measurements as a function of crown-rump length (CRL and GA. Maternal red blood cell folate concentrations were analysed before 8 weeks GA to validate the associations. A total of 263 serial high quality three-dimensional ultrasound scans of 135 pregnancies were studied. Preconceptional compared to postconceptional initiation of folic acid use was associated with slightly larger cerebellar diameters per millimetre increase of CRL (TCD: β = 0.260mm, 95%CI = 0.023-0.491, p<0.05; LCD: β = 0.171mm, 95%CI = 0.038-0.305, p<0.05; RCD: β = 0.156mm, 95%CI = 0.032-0.280, p<0.05 and with proportional cerebellar growth (TCD/CRL:β = 0.015mm/mm, 95%CI = 0.005-0.024, p<0.01; LCD/CRL:β = 0.012mm/mm, 95%CI = 0.005-0.018, p<0.01; RCD/CRL:β = 0.011mm/mm, 95%CI = 0.005-0.017, p<0.01. Cerebellar growth was significantly highest in the third quartile of maternal red blood cell folate levels (1538-1813 nmol/L. These first findings show that periconceptional maternal folate status is associated with human embryonic cerebellar development. Implications of these small but significant variations for fetal cerebellar growth trajectories and the child's neurodevelopmental outcome are yet unknown and warrant further investigation.

  14. Trajectories of problem video gaming among adult regular gamers: an 18-month longitudinal study.

    Science.gov (United States)

    King, Daniel L; Delfabbro, Paul H; Griffiths, Mark D

    2013-01-01

    A three-wave, longitudinal study examined the long-term trajectory of problem gaming symptoms among adult regular video gamers. Potential changes in problem gaming status were assessed at two intervals using an online survey over an 18-month period. Participants (N=117) were recruited by an advertisement posted on the public forums of multiple Australian video game-related websites. Inclusion criteria were being of adult age and having a video gaming history of at least 1 hour of gaming every week over the past 3 months. Two groups of adult video gamers were identified: those players who did (N=37) and those who did not (N=80) identify as having a serious gaming problem at the initial survey intake. The results showed that regular gamers who self-identified as having a video gaming problem at baseline reported more severe problem gaming symptoms than normal gamers, at all time points. However, both groups experienced a significant decline in problem gaming symptoms over an 18-month period, controlling for age, video gaming activity, and psychopathological symptoms.

  15. AIDS-related illness trajectories in Mexico: findings from a qualitative study in two marginalized communities.

    Science.gov (United States)

    Castro, R; Orozco, E; Eroza, E; Manca, M C; Hernández, J J; Aggleton, P

    1998-10-01

    This paper describes findings from a recent study examining how people affected directly and indirectly by the HIV/AIDS epidemic cope with HIV-related illness in Mexico. One-hundred-and-thirteen in-depth interviews were conducted with key informants in two contrasting communities: Ciudad Netzahualcóyotl (an economically marginalized community) and the gay community in Mexico City (a sexually marginalized community). This paper describes the AIDS-related wellness/illness careers or trajectories followed by individuals in both communities, and identifies critical points for material and emotional intervention. This career comprises four stages: (1) life before infection; (2) life surrounding the discovery of seropositivity; (3) living as an HIV-positive person; and (4) facing death. Comparisons are drawn between the processes of adjustment and coping found in both communities. In Ciudad Netzahualcóyotl, wellness/illness careers are closely linked to prevailing poverty and oppression, as well as the sense of urgency in which local people live their lives. In the case of the gay community, wellness/illness careers are associated with the intolerance and social repression faced by homosexual men. The paper concludes by suggesting possible interventions to improve the lives of people with HIV/AIDS in Mexico today.

  16. Trajectories of dietary change and the social context of migration: a qualitative study.

    Science.gov (United States)

    Bojorquez, Ietza; Rentería, Daniela; Unikel, Claudia

    2014-10-01

    The aim of this article was to explore the influence of migration on changes in dietary practices, relating these changes to the social contexts in which they occur. Numerous studies have described how migration from poor countries and regions to more developed ones leads migrants to adopt a modern diet associated to the risk of acquiring chronic diseases. However, different contexts might influence dietary change in migrants in diverse ways. For this purpose, 28 semi-structured interviews were conducted with adult, female internal migrants to a border city in Mexico. The interviews were analyzed using thematic analysis. The results showed trajectories of dietary change to be associated to social position before and after migration. For the participants from rural areas, migration was accompanied by an increase in the consumption of processed foods, and also changes in food insecurity. Migrants who came from urban areas reported a decrease in the perceived quality of food available to them, but their eating pattern was modified only slightly. For some interviewees, migration resulted in the possibility to choose what to eat in a more autonomous way. We discuss how the effect of migration on dietary changes can be manifold, and the necessity to delve into how social context influences these changes.

  17. A SIMULATION STUDY OF DEPOSITION UNDER TWO TYPES OF IMPINGING TRAJECTORIES

    Institute of Scientific and Technical Information of China (English)

    X.Q. Wei; L. Zhou

    2004-01-01

    A model coupling particle aggregation and randomwalk surface diffusion has been developed for 2D simulation of depositionalgrowth, in which impinging particles follow either a straight-line trajectory of cosine distribution, representing typically sputter deposition, or a scattered trajectory, representing typically electrochemical deposition.Simulations of the growth under various impinging conditions and effective surface diffusivity have been carried out. Pattern and defect development in deposition on flat,trenched and ridged substrates have been investigated. We found that on flat and ridged substrates, both types of trajectories yield similar features, including formation of cone-like defects on surface ridges. While on trenched substrate, the straight-line impingement yielded more uniform step coverage than the scattered impingement.

  18. Quasi-Classical Gravity Effect on Neutrino Oscillations in a Gravitational Field of a Heavy Astrophysical Object

    Directory of Open Access Journals (Sweden)

    Jonathan Miller

    2015-01-01

    Full Text Available In the framework of quantum field theory, a graviton interacts locally with a quantum state having definite mass, that is, the gravitational mass eigenstate, while a weak boson interacts with a state having definite flavor, that is, the flavor eigenstate. An interaction of a neutrino with an energetic graviton may trigger the collapse of the neutrino to a definite mass eigenstate with probability expressed in terms of PMNS mixing matrix elements. Thus, gravitons would induce quantum decoherence of a coherent neutrino flavor state similarly to how weak bosons induce quantum decoherence of a neutrino in a definite mass state. We demonstrate that such an essentially quantum gravity effect may have strong consequences for neutrino oscillation phenomena in astrophysics due to relatively large scattering cross sections of relativistic neutrinos undergoing large angle radiation of energetic gravitons in gravitational field of a classical massive source (i.e., the quasi-classical case of gravitational Bethe-Heitler scattering. This graviton-induced decoherence is compared to decoherence due to propagation in the presence of the Earth matter effect. Based on this study, we propose a new technique for the indirect detection of energetic gravitons by measuring the flavor composition of astrophysical neutrinos.

  19. The ortho-to-para ratio of interstellar NH$_2$: Quasi-classical trajectory calculations and new simulations

    CERN Document Server

    Gal, Romane Le; Xie, Changjian; Li, Anyang; Guo, Hua

    2016-01-01

    Based on recent $Herschel$ results, the ortho-to-para ratio (OPR) of NH$_2$ has been measured towards the following high-mass star-forming regions: W31C (G10.6-0.4), W49N (G43.2-0.1), W51 (G49.5-0.4), and G34.3+0.1. The OPR at thermal equilibrium ranges from the statistical limit of three at high temperatures to infinity as the temperature tends toward zero, unlike the case of H$_{2}$. Depending on the position observed along the lines-of-sight, the OPR was found to lie either slightly below the high temperature limit of three (in the range $2.2-2.9$) or above this limit ($\\sim3.5$, $\\gtrsim 4.2$, and $\\gtrsim 5.0$). In low temperature interstellar gas, where the H$_{2}$ is para-enriched, our nearly pure gas-phase astrochemical models with nuclear-spin chemistry can account for anomalously low observed NH$_2$-OPR values. We have tentatively explained OPR values larger than three by assuming that spin thermalization of NH$_2$ can proceed at least partially by H-atom exchange collisions with atomic hydrogen, th...

  20. Trajectories of Marijuana Use among HIV-seropositive and HIV-seronegative MSM in the Multicenter AIDS Cohort Study (MACS), 1984-2013.

    Science.gov (United States)

    Okafor, Chukwuemeka N; Cook, Robert L; Chen, Xinguang; Surkan, Pamela J; Becker, James T; Shoptaw, Steve; Martin, Eileen; Plankey, Michael W

    2017-04-01

    To construct longitudinal trajectories of marijuana use in a sample of men who have sex with men living with or at-risk for HIV infection. We determined factors associated with distinct trajectories of use as well as those that serve to modify the course of the trajectory. Data were from 3658 [1439 HIV-seropositive (HIV+) and 2219 HIV-seronegative (HIV-)] participants of the Multicenter AIDS Cohort Study. Frequency of marijuana use was obtained semiannually over a 29-year period (1984-2013). Group-based trajectory models were used to identify the trajectories and to determine predictors and modifiers of the trajectories over time. Four distinct trajectories of marijuana use were identified: abstainer/infrequent (65 %), decreaser (13 %), increaser (12 %) and chronic high (10 %) use groups. HIV+ status was significantly associated with increased odds of membership in the decreaser, increaser and chronic high use groups. Alcohol, smoking, stimulant and other recreational drug use were associated with increasing marijuana use across all four trajectory groups. Antiretroviral therapy use over time was associated with decreasing marijuana use in the abstainer/infrequent and increaser trajectory groups. Having a detectable HIV viral load was associated with increasing marijuana use in the increaser group only. Future investigations are needed to determine whether long-term patterns of use are associated with adverse consequences especially among HIV+ persons.

  1. The injury trajectory for young people 16-24 years in the six months following injury: A mixed methods study.

    Science.gov (United States)

    Ogilvie, Rebekah; Foster, Kim; McCloughen, Andrea; Curtis, Kate

    2016-09-01

    Adolescents and young people are the population at greatest risk of injury and therefore injury-related mortality and morbidity. Inquiry into the injury trajectory of young people is needed to identify this group's specific needs for healthcare. This paper reports the integration of quantitative and qualitative findings from a sequential explanatory mixed methods study examining young people aged 16-24 years' experience and trajectory of traumatic physical injury in the initial six months. The aim of integration was to address the question: In what ways are injured young peoples' experiences and self-management during the initial six months of the injury trajectory impacted by their injury, family support, and provision of healthcare? Key findings from epidemiological datasets on young person injuries from hospital and coronial databases (Phase 1) were combined with key findings from qualitative interviews with 12 injured young people and 10 family members (Phase 2). The integration of findings from Phase 1 and Phase 2 resulted in three new findings; [1] (Alfred Health, 2014). A young person's perception of the severity of their injury, as well as the amount of time spent in hospital, impacts substantially on the way in which they experience injury, and this is managed differently between genders; [2] (Newnam et al., 2014). Admission to an Intensive care unit, including the intensity and duration of care, is the primary influence on how a family will provide support to the young person in the inpatient period; and [3] (Lyons et al., 2010). Young people's perception and understanding of their recovery from injury is in contrast with how healthcare systems are structured to provide rehabilitation and recovery care. The injury trajectory and recovery process of young people in the six months following injury have been have conceptualised. These trajectories of recovery can inform the development of anticipatory guidance frameworks for clinicians and guide the

  2. What can providers learn from childhood body mass index trajectories: a study of a large, safety-net clinical population.

    Science.gov (United States)

    McCormick, Emily V; Dickinson, L Miriam; Haemer, Matthew A; Knierim, Shanna D; Hambidge, Simon J; Davidson, Arthur J

    2014-01-01

    To describe childhood weight gain using body mass index (BMI) z-score trajectories in a low-income urban safety-net population and identify among gender- and race/ethnicity-specific groups any trends for increased risk. A retrospective cohort study was conducted among 2- to 12-year-old patients (2006-2013) visiting a safety-net provider. BMI z-score trajectories were calculated overall, for gender- and race/ethnicity-specific groups, and for peak BMI percentile subgroups to describe weight gain longitudinally. From 2006 to 2013, a total of 26,234 eligible children were followed for an average of 3.7 years. At baseline (mean age, 4.2 years), 74% of patients were at a normal weight compared to 65% at most recent observation (mean age, 7.8 years). All gender and race/ethnicity subgroups showed increasing average BMI z-scores during childhood. Children consistently under the 50th percentile and those of white race had the most stable BMI z-score trajectories. BMI z-score increased with increasing age in all subgroups. Hispanic boys and black girls had the most significant increase in BMI z-score during this observation period. Children observed in early childhood and whose BMI exceeded the 95th percentile at any time were often already overweight (20%) or obese (36%) by 3 years of age. The entire population demonstrated an upward trend in BMI z-score trajectory. This trend was most notable among black girls and Hispanic boys. Many obese children were already overweight by age 3, and persistence of obesity after 3 years of age was high, suggesting that intervention before age 3 may be essential to curbing unhealthy weight trajectories. Copyright © 2014 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  3. Design Decisions in Developing Learning Trajectories-Based Assessments in Mathematics: A Case Study

    Science.gov (United States)

    Penuel, William R.; Confrey, Jere; Maloney, Alan; Rupp, André A.

    2014-01-01

    This article analyzes the design decisions of a team developing diagnostic assessments for a learning trajectory focused on rational number reasoning. The analysis focuses on the design rationale for key decisions about how to develop the cognitive assessments and related validity arguments within a fluid state and national policy context. The…

  4. The Career Trajectories of English Language Teachers. Oxford Studies in Comparative Education

    Science.gov (United States)

    Haworth, Penny, Ed.; Craig, Cheryl, Ed.

    2016-01-01

    This volume identifies, illustrates, compares, contrasts and provides informed reflective commentary on the diverse career trajectories of English language teachers, teacher educators and researchers. Increased migration and globalisation pressures have led to dramatic changes in English language teaching over the last few decades. The resulting…

  5. Periconception Maternal Folate Status and Human Embryonic Cerebellum Growth Trajectories : The Rotterdam Predict Study

    NARCIS (Netherlands)

    Koning, Irene V; Groenenberg, Irene A L; Gotink, Anniek W; Willemsen, Sten P; Gijtenbeek, Manon; Dudink, Jeroen; Go, Attie T J I; Reiss, Irwin K M; Steegers, Eric A P; Steegers-Theunissen, Régine P M

    2015-01-01

    We aimed to investigate whether periconceptional maternal folate status affects human embryonic cerebellar size and growth trajectories. In a prospective periconceptional cohort participants filled out questionnaires and received weekly transvaginal 3D-ultrasounds between 7+0 and 12+6 weeks

  6. Periconception maternal folate status and human embryonic cerebellum growth trajectories: The Rotterdam predict study

    NARCIS (Netherlands)

    I.V. Koning (Irene); I.A.L. Groenenberg (Irene); A.W. Gotink (Anniek W.); S. Willemsen (Sp); M. Gijtenbeek (M.); J. Dudink (Jeroen); A.T.J.I. Go (Attie T. J. I.); I.K.M. Reiss (Irwin); E.A.P. Steegers (Eric); R.P.M. Steegers-Theunissen (Régine)

    2015-01-01

    textabstractWe aimed to investigate whether periconceptional maternal folate status affects human embryonic cerebellar size and growth trajectories. In a prospective periconceptional cohort participants filled out questionnaires and received weekly transvaginal 3D-ultrasounds between 7+0 and 12+6

  7. Assessing transition trajectories towards a sustainable energy system: A case study on the Dutch transition to climate-neutral transport fuel chains

    NARCIS (Netherlands)

    Suurs, R.A.A.; Hekkert, M.P.; Meeus, M.T.H.; Nieuwlaar, E.

    2004-01-01

    This paper proposes a method for the ex ante evaluation of technological trajectories. As a case we study the Dutch transport energy system and its transition to climate neutrality. Two technological trajectories are proposed: (i) a sequence of transition steps based on radical infrastructural chang

  8. Trajectories in Operating a Handheld Tool

    Science.gov (United States)

    Heuer, Herbert; Sulzenbruck, Sandra

    2009-01-01

    The authors studied the trajectories of the hand and of the tip of a handheld sliding first-order lever in aiming movements. With this kind of tool, straight trajectories of the hand are generally associated with curved trajectories of the tip of the lever and vice versa. Trajectories of the tip of the lever exhibited smaller deviations from…

  9. Trajectories in Operating a Handheld Tool

    Science.gov (United States)

    Heuer, Herbert; Sulzenbruck, Sandra

    2009-01-01

    The authors studied the trajectories of the hand and of the tip of a handheld sliding first-order lever in aiming movements. With this kind of tool, straight trajectories of the hand are generally associated with curved trajectories of the tip of the lever and vice versa. Trajectories of the tip of the lever exhibited smaller deviations from…

  10. Symptom Trajectories Among Child Survivors of Maltreatment: Findings from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN).

    Science.gov (United States)

    Lauterbach, Dean; Armour, Cherie

    2016-02-01

    Very few studies have investigated the longitudinal trajectory of depression and anxiety related symptomatology among child victims of maltreatment or among those at risk for maltreatment. The current study examined latent class trajectories of anxiety/depression symptoms in a sample of 1354 (n = 657 boys, n = 697 girls) victimized or at risk children using data collected from the Longtitudinal Studies of Child Abuse and Neglect (LONGSCAN). Four trajectory groups were identified labeled low-stable, moderate-stable, moderate-increasing, and high-decreasing. This study also sought to investigate predictors of group membership. Relative to the low-stable group, membership in the three more pathological groups (i.e., moderate-stable, moderate-increasing, and high-decreasing) was predicted by a greater number of maltreatment allegations, more visits to a primary care physician for psychological issues, less perceived support by primary maternal caregiver, and lower rated popularity of the child. Implications for early identification of child maltreatment victims in primary health care settings was discussed.

  11. Associations of education with 30 year life course blood pressure trajectories: Framingham Offspring Study

    Directory of Open Access Journals (Sweden)

    Xiao Yongling

    2011-02-01

    Full Text Available Abstract Background Education is inversely associated with cardiovascular disease incidence in developed countries. Blood pressure may be an explanatory biological mechanism. However few studies have investigated educational gradients in longitudinal blood pressure trajectories, particularly over substantial proportions of the life course. Study objectives were to determine whether low education was associated with increased blood pressure from multiple longitudinal assessments over 30 years. Furthermore, we aimed to separate antecedent effects of education, and other related factors, that might have caused baseline differences in blood pressure, from potential long-term effects of education on post-baseline blood pressure changes. Methods The study examined 3890 participants of the Framingham Offspring Study (mean age 36.7 years, 52.0% females at baseline from 1971 through 2001 at up to 7 separate examinations using multivariable mixed linear models. Results Mixed linear models demonstrated that mean systolic blood pressure (SBP over 30 years was higher for participants with ≤12 vs. ≥17 years education after adjusting for age (3.26 mmHg, 95% CI: 1.46, 5.05 in females, 2.26 mmHg, 95% CI: 0.87, 3.66 in males. Further adjustment for conventional covariates (antihypertensive medication, smoking, body mass index and alcohol reduced differences in females and males (2.86, 95% CI: 1.13, 4.59, and 1.25, 95% CI: -0.16, 2.66 mmHg, respectively. Additional analyses adjusted for baseline SBP, to evaluate if there may be educational contributions to post-baseline SBP. In analyses adjusted for age and baseline SBP, females with ≤12 years education had 2.69 (95% CI: 1.09, 4.30 mmHg higher SBP over follow-up compared with ≥17 years education. Further adjustment for aforementioned covariates slightly reduced effect strength (2.53 mmHg, 95% CI: 0.93, 4.14. Associations were weaker in males, where those with ≤12 years education had 1.20 (95% CI: -0

  12. Socioeconomic position predicts long-term depression trajectory: a 13-year follow-up of the GAZEL cohort study.

    Science.gov (United States)

    Melchior, M; Chastang, J-F; Head, J; Goldberg, M; Zins, M; Nabi, H; Younès, N

    2013-01-01

    Individuals with low socioeconomic position have high rates of depression; however, it is not clear whether this reflects higher incidence or longer persistence of disorder. Past research focused on high-risk samples, and risk factors of long-term depression in the population are less well known. Our aim was to test the hypothesis that socioeconomic position predicts depression trajectory over 13 years of follow-up in a community sample. We studied 12 650 individuals participating in the French GAZEL study. Depression was assessed by the Center for Epidemiological Studies-Depression scale in 1996, 1999, 2002, 2005 and 2008. These five assessments served to estimate longitudinal depression trajectories (no depression, decreasing depression, intermediate/increasing depression, persistent depression). Socioeconomic position was measured by occupational grade. Covariates included year of birth, marital status, tobacco smoking, alcohol consumption, body mass index, negative life events and preexisting psychological and non-psychological health problems. Data were analyzed using multinomial regression, separately in men and women. Overall, participants in intermediate and low occupational grades were significantly more likely than those in high grades to have an unfavorable depression trajectory and to experience persistent depression (age-adjusted ORs: respectively 1.40, 95% confidence interval (CI) 1.16-1.70 and 2.65, 95% CI 2.04-3.45 in men, 2.48, 95% CI 1.36-4.54 and 4.53, 95% CI 2.38-8.63 in women). In multivariate models, the socioeconomic gradient in long-term depression decreased by 21-59% in men and women. Long-term depression trajectories appear to follow a socioeconomic gradient; therefore, efforts aiming to reduce the burden of depression should address the needs of the whole population rather than exclusively focus on high-risk groups.

  13. Telomere length trajectory and its determinants in persons with coronary artery disease: longitudinal findings from the heart and soul study.

    Directory of Open Access Journals (Sweden)

    Ramin Farzaneh-Far

    Full Text Available BACKGROUND: Leukocyte telomere length, an emerging marker of biological age, has been shown to predict cardiovascular morbidity and mortality. However, the natural history of telomere length in patients with coronary artery disease has not been studied. We sought to investigate the longitudinal trajectory of telomere length, and to identify the independent predictors of telomere shortening, in persons with coronary artery disease. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective cohort study of 608 individuals with stable coronary artery disease, we measured leukocyte telomere length at baseline, and again after five years of follow-up. We used multivariable linear and logistic regression models to identify the independent predictors of leukocyte telomere trajectory. Baseline and follow-up telomere lengths were normally distributed. Mean telomere length decreased by 42 base pairs per year (p<0.001. Three distinct telomere trajectories were observed: shortening in 45%, maintenance in 32%, and lengthening in 23% of participants. The most powerful predictor of telomere shortening was baseline telomere length (OR per SD increase = 7.6; 95% CI 5.5, 10.6. Other independent predictors of telomere shortening were age (OR per 10 years = 1.6; 95% CI 1.3, 2.1, male sex (OR = 2.4; 95% CI 1.3, 4.7, and waist-to-hip ratio (OR per 0.1 increase = 1.4; 95% CI 1.0, 2.0. CONCLUSIONS/SIGNIFICANCE: Leukocyte telomere length may increase as well as decrease in persons with coronary artery disease. Telomere length trajectory is powerfully influenced by baseline telomere length, possibly suggesting negative feedback regulation. Age, male sex, and abdominal obesity independently predict telomere shortening. The mechanisms and reversibility of telomeric aging in cardiovascular disease deserve further study.

  14. Pedestrian Crosswalk Law: A study of traffic and trajectory factors that affect non-compliance and stopping distance.

    Science.gov (United States)

    Figliozzi, Miguel A; Tipagornwong, Chawalit

    2016-11-01

    Walking is encouraged by many transportation agencies as a sustainable mode that contributes to livable downtowns. Since pedestrians are the most vulnerable road users, safe and comfortable crosswalks are essential to ensure that pedestrian travel becomes an appealing alternative. In this context, the goal of this research is to study the traffic and vehicle trajectory factors that affect crosswalk law compliance and stopping distance from the crosswalk. The results of this research provide new insights into the relationships between traffic conditions, vehicle trajectory, and compliance rates. Results indicate that vehicle origin, vehicle type, stopping at upstream traffic lights, and changes in vehicle speed and headways are key factors to predict pedestrian crosswalk law compliance and stopping behavior; changes in vehicle speed and headways have the highest explanatory power.

  15. Experimentally measured susceptibility to peer influence and adolescent sexual behavior trajectories: A preliminary study.

    Science.gov (United States)

    Choukas-Bradley, Sophia; Giletta, Matteo; Widman, Laura; Cohen, Geoffrey L; Prinstein, Mitchell J

    2014-09-01

    A performance-based measure of peer influence susceptibility was examined as a moderator of the longitudinal association between peer norms and trajectories of adolescents' number of sexual intercourse partners. Seventy-one 9th grade adolescents (52% female) participated in an experimental "chat room" paradigm involving "e-confederates" who endorsed sexual risk behaviors. Changes in participants' responses to risk scenarios before versus during the "chat room" were used as a performance-based measure of peer influence susceptibility. Participants reported their perceptions of popular peers' number of sexual intercourse partners at baseline and self-reported their number of sexual intercourse partners at baseline and 6, 12, and 18 months later. Susceptibility was examined as a moderator of the longitudinal association between perceptions of popular peers' number of sexual intercourse partners and trajectories of adolescents' own numbers of partners. High perceptions of the number of popular peers' sexual intercourse partners combined with high peer influence susceptibility predicted steeper longitudinal trajectories of adolescents' number of partners. Results provide novel preliminary evidence regarding the importance of peer influence susceptibility in adolescents' development of sexual behaviors.

  16. Trajectory study of supercollision relaxation in highly vibrationally excited pyrazine and CO2.

    Science.gov (United States)

    Li, Ziman; Sansom, Rebecca; Bonella, Sara; Coker, David F; Mullin, Amy S

    2005-09-01

    Classical trajectory calculations were performed to simulate state-resolved energy transfer experiments of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) and CO(2), which were conducted using a high-resolution transient infrared absorption spectrometer. The goal here is to use classical trajectories to simulate the supercollision energy transfer pathway wherein large amounts of energy are transferred in single collisions in order to compare with experimental results. In the trajectory calculations, Newton's laws of motion are used for the molecular motion, isolated molecules are treated as collections of harmonic oscillators, and intermolecular potentials are formed by pairwise Lennard-Jones potentials. The calculations qualitatively reproduce the observed energy partitioning in the scattered CO(2) molecules and show that the relative partitioning between bath rotation and translation is dependent on the moment of inertia of the bath molecule. The simulations show that the low-frequency modes of the vibrationally excited pyrazine contribute most to the strong collisions. The majority of collisions lead to small DeltaE values and primarily involve single encounters between the energy donor and acceptor. The large DeltaE exchanges result from both single impulsive encounters and chattering collisions that involve multiple encounters.

  17. Identifying Latent Trajectories of Personality Disorder Symptom Change: Growth Mixture Modeling in the Longitudinal Study of Personality Disorders

    Science.gov (United States)

    Hallquist, Michael N.; Lenzenweger, Mark F.

    2013-01-01

    Although previous reports have documented mean-level declines in personality disorder (PD) symptoms over time, little is known about whether personality pathology sometimes emerges among nonsymptomatic adults, or whether rates of change differ qualitatively among symptomatic persons. Our study sought to characterize heterogeneity in the longitudinal course of PD symptoms with the goal of testing for and describing latent trajectories. Participants were 250 young adults selected into two groups using a PD screening measure: those who met diagnostic criteria for a DSM-III-R PD (PPD, n = 129), and those with few PD symptoms (NoPD, n = 121). PD symptoms were assessed three times over a four-year study using semistructured interviews. Total PD symptom counts and symptoms of each DSM-III-R PD were analyzed using growth mixture modeling. In the NoPD group, latent trajectories were characterized by stable, minor symptoms; the rapid or gradual remission of subclinical symptoms; or the emergence of symptoms of Avoidant, Obsessive-Compulsive, or Paranoid PD. In the PPD group, three latent trajectories were evident: rapid symptom remission, slow symptom decline, or a relative absence of symptoms. Rapid remission of PD symptoms was associated with fewer comorbid disorders, lower negative emotionality, and greater positive emotionality and constraint, whereas emergent personality dysfunction was associated with comorbid PD symptoms and lower positive emotionality. In most cases, symptom change for one PD was associated with concomitant changes in other PDs, depressive symptoms, and anxiety. These results indicate that the longitudinal course of PD symptoms is heterogeneous, with distinct trajectories evident for both symptomatic and nonsymptomatic individuals. The prognosis of PD symptoms may be informed by an assessment of personality and comorbid psychopathology. PMID:23231459

  18. Identifying latent trajectories of personality disorder symptom change: growth mixture modeling in the longitudinal study of personality disorders.

    Science.gov (United States)

    Hallquist, Michael N; Lenzenweger, Mark F

    2013-02-01

    Although previous reports have documented mean-level declines in personality disorder (PD) symptoms over time, little is known about whether personality pathology sometimes emerges among nonsymptomatic adults, or whether rates of change differ qualitatively among symptomatic persons. Our study sought to characterize heterogeneity in the longitudinal course of PD symptoms with the goal of testing for and describing latent trajectories. Participants were 250 young adults selected into two groups using a PD screening measure: those who met diagnostic criteria for a DSM-III-R PD (PPD, n = 129), and those with few PD symptoms (NoPD, n = 121). PD symptoms were assessed three times over a 4-year study using semistructured interviews. Total PD symptom counts and symptoms of each DSM-III-R PD were analyzed using growth mixture modeling. In the NoPD group, latent trajectories were characterized by stable, minor symptoms; the rapid or gradual remission of subclinical symptoms; or the emergence of symptoms of avoidant, obsessive-compulsive, or paranoid PD. In the PPD group, three latent trajectories were evident: rapid symptom remission, slow symptom decline, or a relative absence of symptoms. Rapid remission of PD symptoms was associated with fewer comorbid disorders, lower Negative Emotionality, and greater Positive Emotionality and Constraint, whereas emergent personality dysfunction was associated with comorbid PD symptoms and lower Positive Emotionality. In most cases, symptom change for one PD was associated with concomitant changes in other PDs, depressive symptoms, and anxiety. These results indicate that the longitudinal course of PD symptoms is heterogeneous, with distinct trajectories evident for both symptomatic and nonsymptomatic individuals. The prognosis of PD symptoms may be informed by an assessment of personality and comorbid psychopathology.

  19. Quasiclassical approach to high-energy QED processes in strong laser and atomic fields

    CERN Document Server

    Di Piazza, A

    2012-01-01

    An approach, based on the use of the quasiclassical Green's function, is developed for investigating high-energy quantum electrodynamical processes in combined strong laser and atomic fields. Employing an operator technique, we derive the Green's function of the Dirac equation in an arbitrary plane wave and a localized potential. Then, we calculate the total cross section of high-energy electron-positron photoproduction in an atomic field of arbitrary charge number (Bethe-Heitler process) in the presence of a strong laser field. It is shown that the laser field substantially modifies the cross section at already available incoming photon energies and laser parameters. This makes it feasible to observe the analogous effect in a laser field of the Landau-Pomeranchuk-Migdal effect for the Bethe-Heitler process.

  20. A Cartesian quasi-classical model to nonequilibrium quantum transport: the Anderson impurity model.

    Science.gov (United States)

    Li, Bin; Levy, Tal J; Swenson, David W H; Rabani, Eran; Miller, William H

    2013-03-14

    We apply the recently proposed quasi-classical approach for a second quantized many-electron Hamiltonian in Cartesian coordinates [B. Li and W. H. Miller, J. Chem. Phys. 137, 154107 (2012)] to correlated nonequilibrium quantum transport. The approach provides accurate results for the resonant level model for a wide range of temperatures, bias, and gate voltages, correcting the flaws of our recently proposed mapping using action-angle variables. When electron-electron interactions are included, a Gaussian function scheme is required to map the two-electron integrals, leading to quantitative results for the Anderson impurity model. In particular, we show that the current mapping is capable of capturing quantitatively the Coulomb blockade effect and the temperature dependence of the current below and above the blockade.

  1. Quasiclassical approach to nonlocal generalized London equation in mixed state of s -wave superconductors

    Science.gov (United States)

    Laiho, R.; Safonchik, M.; Traito, K. B.

    2007-05-01

    We extend the Ginsburg-Landau solution for cutoff function in London equation to low temperatures by solving numerically the quasiclassical Eilenberger equations in mixed state of s -wave superconductors. As a result the nonlocal generalized London equation (NGLE) is obtained. The magnetic field and temperature dependence of the cutoff function parameter k1(B,T) are calculated. Due to Kramer-Pesch effect k1 decreases strongly at low temperatures. It is also found that k1 has a minimum at a value of magnetic field depending on temperature. We reduce the NGLE model to an effective local model and calculate the value of an effective penetration depth λeff(B,T) . The sublinear field dependence of λeff is predicted that agrees with experimental μ SR results for the penetration depth of magnetic field in the s -wave superconductor V3Si and NbSe2 .

  2. Q-Deformed Bosons at Quasi-classical Limit of SO(3)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; GAO Yi-Bo; LI Yan-Min

    2009-01-01

    When a boson interacts with another to form a composite system with SO(3) dynamic symmetry, it is shown that there exists the q-deformed bosonic excitation satisfying the q-deformed Heisenberg commutation relation in the quasi-classical limit that the angular momentum j for SO(3) is large, but not infinite. In second quantization this quasi-excitation is associated with the boson realization of SO(3) Lie algebra. Physically, the phenomena of q-deformed excitation can happen in many models of quantum dynamics, such as super emission from a system of many identical two-level atoms, the spin wave in Heisenberg chain, the high spin precession and the coherent output of Bose--Einstein atoms in a trap. Especially, in these models, the deformation parameter q is well defined intrinsically by a conservative quantity, such as the total atomic number and the angular momentum.

  3. Chains of Quasi-Classical Informations for Bipartite Correlations and the Role of Twin Observables

    CERN Document Server

    Herbut, F

    2002-01-01

    Having the quantum correlations in a general bipartite state in mind, the information accessible by simultaneous measurement on both subsystems is shown never to exceed the information accessible by measurement on one subsystem, which, in turn is proved not to exceed the von Neumann mutual information. A particular pair of (opposite- subsystem) observables are shown to be responsible both for the amount of quasi-classical correlations and for that of the purely quantum entanglement in the pure-state case: the former via simultaneous subsystem measurements, and the latter through the entropy of coherence or of incompatibility, which is defined for the general case. The observables at issue are so-called twin observables. A general definition of the latter is given in terms of their detailed properties.

  4. Quantum information processing using quasiclassical electromagnetic interactions between qubits and electrical resonators

    CERN Document Server

    Kerman, Andrew J

    2012-01-01

    Electrical resonators are widely used in quantum information processing with any qubits that are manipulated via electromagnetic interactions. In nearly all examples to date they are engineered to interact with qubits via real or virtual exchange of (typically microwave) photons, and the resonator must therefore have both a high quality factor and strong quantum fluctuations, corresponding to the strong-coupling limit of cavity QED. Although great strides in the control of quantum information have been made using this so-called "circuit QED" architecture, it also comes with some important disadvantages. In this paper, we discuss a new paradigm for coupling qubits electromagnetically via resonators, in which the qubits do not exchange photons with the resonator, but instead where the qubits exert quasi-classical, effective "forces" on it. We show how this type of interaction is similar to that induced between the internal state of a trapped atomic ion and its center-of-mass motion by the photon recoil momentum...

  5. Aberrant parietal cortex developmental trajectories in girls with Turner syndrome and related visual-spatial cognitive development: a preliminary study.

    Science.gov (United States)

    Green, Tamar; Chromik, Lindsay C; Mazaika, Paul K; Fierro, Kyle; Raman, Mira M; Lazzeroni, Laura C; Hong, David S; Reiss, Allan L

    2014-09-01

    Turner syndrome (TS) arises from partial or complete absence of the X-chromosome in females. Girls with TS show deficits in visual-spatial skills as well as reduced brain volume and surface area in the parietal cortex which supports these cognitive functions. Thus, measuring the developmental trajectory of the parietal cortex and the associated visual-spatial cognition in TS may provide novel insights into critical brain-behavior associations. In this longitudinal study, we acquired structural MRI data and assessed visual-spatial skills in 16 (age: 8.23 ± 2.5) girls with TS and 13 age-matched controls over two time-points. Gray and white matter volume, surface area and cortical thickness were calculated from surfaced based segmentation of bilateral parietal cortices, and the NEPSY Arrows subtest was used to assess visual-spatial ability. Volumetric and cognitive scalars were modeled to obtain estimates of age-related change. The results show aberrant growth of white matter volume (P = 0.011, corrected) and surface area (P = 0.036, corrected) of the left superior parietal regions during childhood in girls with TS. Other parietal sub-regions were significantly smaller in girls with TS at both time-points but did not show different growth trajectories relative to controls. Furthermore, we found that visual-spatial skills showed a widening deficit for girls with TS relative to controls (P = 0.003). Young girls with TS demonstrate an aberrant trajectory of parietal cortical and cognitive development during childhood. Elucidating aberrant neurodevelopmental trajectories in this population is critical for determining specific stages of brain maturation that are particularly dependent on TS-related genetic and hormonal factors. © 2014 Wiley Periodicals, Inc.

  6. Project STARS (Studies on Trajectories of Adolescent Relationships and Sexuality) : A longitudinal, multi-domain study on sexual development of Dutch adolescents

    NARCIS (Netherlands)

    Reitz, Ellen; van de Bongardt, Daphne; Baams, Laura; Doornwaard, Suzan; Dalenberg, Wieke; Dubas, Judith; van Aken, Marcel; Overbeek, Geertjan; ter Bogt, Tom; van der Eijnden, Regina; Vanwesenbeeck, Ine; Timmerman, Greetje; Kunnen, Elske; van Geert, Paul; Dekovic, Maja

    2015-01-01

    This study gives an overview of Project STARS (Studies on Trajectories of Adolescent Relationships and Sexuality), a four-wave longitudinal study of 1297 Dutch adolescents. First, the sample, measures and four sub-projects are described. Second, hierarchical regression analyses were conducted to

  7. Project STARS (Studies on Trajectories of Adolescent Relationships and Sexuality): A longitudinal, multi-domain study on sexual development of Dutch adolescents

    NARCIS (Netherlands)

    Reitz, E.; van de Bongardt, D.; Baams, L.; Doornwaard, S.; Dalenberg, W.; Dubas, J.; van Aken, M.; Overbeek, G.; ter Bogt, T.; van der Eijnden, R.; Vanwesenbeeck, I.; Kunnen, S.; Timmerman, G.; van Geert, P.; Deković, M.

    2015-01-01

    This study gives an overview of Project STARS (Studies on Trajectories of Adolescent Relationships and Sexuality), a four-wave longitudinal study of 1297 Dutch adolescents. First, the sample, measures and four sub-projects are described. Second, hierarchical regression analyses were conducted to

  8. Combined effect of education and reproductive history on weight trajectories of young Australian women: A longitudinal study.

    Science.gov (United States)

    Holowko, Natalie; Jones, Mark; Koupil, Ilona; Tooth, Leigh; Mishra, Gita

    2016-10-01

    To investigate the combined effect of education and reproductive history on weight trajectory. The association of education with weight trajectory (1996-2012) in relation to reproductive history was analyzed among 9,336 women (born 1973-1978) from the Australian Longitudinal Study on Women's Health using random effects models. Compared with women with a university degree/higher, lower-educated women were 2 kg heavier at baseline and gained an additional 0.24 kg/year. Giving birth was associated with an increase in weight which was more pronounced among women having their first birth 32 years. While younger first-time mothers had a steeper weight trajectory (∼+0.16 kg/year, 95% CI: 0.1-0.3), this was less steep among lower-educated women. High-educated women with a second birth between 26 and 32 years had 0.9 kg decreased weight after this birth, while low-educated women gained 0.9 kg. While the effect of having children on weight in young adulthood was minimal, women having their first birth Educational differences in weight persisted after accounting for reproductive history, suggesting a need to explore alternative mechanisms through which social differences in weight are generated. © 2016 The Obesity Society.

  9. Sampling microcanonical ensembles of trajectories using harmonic approximation in internal coordinates.

    Science.gov (United States)

    Rybkin, Vladimir V; Ekström, Ulf

    2014-08-14

    In this paper, we modify quasiclassical harmonic sampling of microcanonical ensembles of trajectories by using the curvilinear internal coordinates. The harmonic approximation in the curvilinear normal coordinates provides a more realistic description of the PES than in the conventional rectilinear ones at finite displacements. Therefore, the sampling of vibrations in the internal coordinates significantly improves the quality of the sampling in a block-box fashion, providing more realistic displacements and reducing the errors in the potential energy. In particular, the sampling of large-amplitude torsion vibrations, which is non-realistic in the Cartesian modes, becomes accurate or acceptable in the curvilinear modes.

  10. Differentially Private Trajectory Data Publication

    CERN Document Server

    Chen, Rui; Desai, Bipin C

    2011-01-01

    With the increasing prevalence of location-aware devices, trajectory data has been generated and collected in various application domains. Trajectory data carries rich information that is useful for many data analysis tasks. Yet, improper publishing and use of trajectory data could jeopardize individual privacy. However, it has been shown that existing privacy-preserving trajectory data publishing methods derived from partition-based privacy models, for example k-anonymity, are unable to provide sufficient privacy protection. In this paper, motivated by the data publishing scenario at the Societe de transport de Montreal (STM), the public transit agency in Montreal area, we study the problem of publishing trajectory data under the rigorous differential privacy model. We propose an efficient data-dependent yet differentially private sanitization algorithm, which is applicable to different types of trajectory data. The efficiency of our approach comes from adaptively narrowing down the output domain by building...

  11. Child- and parent-reported quality of life trajectories in children with epilepsy: A prospective cohort study.

    Science.gov (United States)

    Ferro, Mark A; Avery, Lisa; Fayed, Nora; Streiner, David L; Cunningham, Charles E; Boyle, Michael H; Lach, Lucyna; Glidden, Gina; Rosenbaum, Peter L; Ronen, Gabriel M

    2017-07-01

    To describe the developmental trajectories of quality of life (QoL) in a large cohort of children with epilepsy, and to assess the relative contribution of clinical, psychosocial, and sociodemographic variables on QoL trajectories. Five assessments during a 28-month prospective cohort study were used to model trajectories of QoL. Participants were recruited with their parents from six Canadian tertiary centers. A convenience sample of 506 children aged 8-14 years with epilepsy and without intellectual disability or autism spectrum disorder were enrolled. A total of 894 children were eligible and 330 refused participation. Participating children were, on average, 11.4 years of age, and 49% were female. Nearly one third (32%) had partial seizures. At baseline, 479 and 503 child- and parent-reported questionnaires were completed. In total, 354 children (74%) and 366 parents (73%) completed the 28-month follow-up. QoL was measured using the child- and parent-reported version of the Childhood Epilepsy QoL scale (CHEQOL-25). Child-reported QoL was fitted best by a six-class model and parent-reported QoL by a five-class model. In both models, trajectories remained either stable or improved over 28 months. Of these children, 62% rated their QoL as high or moderately high, defined as at least one standard deviation above the average CHEQOL-25 score. Greater family, classmate, and peer social support, fewer symptoms of child and parent depression, and higher receptive vocabulary were identified as the most robust predictors of better QoL (all p < 0.001). Most children with epilepsy and their parents reported relatively good QoL in this first joint self- and proxy-reported trajectory study. Findings confirm the heterogeneous QoL outcomes for children with epilepsy and the primary importance of psychosocial factors rather than seizure and AED-specific factors in influencing QoL. These predictors that are potentially amenable to change should now be the focus of specific

  12. Latent trajectory studies: the basics, how to interpret the results, and what to report

    Directory of Open Access Journals (Sweden)

    Rens van de Schoot

    2015-03-01

    Full Text Available Background: In statistics, tools have been developed to estimate individual change over time. Also, the existence of latent trajectories, where individuals are captured by trajectories that are unobserved (latent, can be evaluated (Muthén & Muthén, 2000. The method used to evaluate such trajectories is called Latent Growth Mixture Modeling (LGMM or Latent Class Growth Modeling (LCGA. The difference between the two models is whether variance within latent classes is allowed for (Jung & Wickrama, 2008. The default approach most often used when estimating such models begins with estimating a single cluster model, where only a single underlying group is presumed. Next, several additional models are estimated with an increasing number of clusters (latent groups or classes. For each of these models, the software is allowed to estimate all parameters without any restrictions. A final model is chosen based on model comparison tools, for example, using the BIC, the bootstrapped chi-square test, or the Lo-Mendell-Rubin test. Method: To ease the use of LGMM/LCGA step by step in this symposium (Van de Schoot, 2015 guidelines are presented which can be used for researchers applying the methods to longitudinal data, for example, the development of posttraumatic stress disorder (PTSD after trauma (Depaoli, van de Schoot, van Loey, & Sijbrandij, 2015; Galatzer-Levy, 2015. The guidelines include how to use the software Mplus (Muthén & Muthén, 1998–2012 to run the set of models needed to answer the research question: how many latent classes exist in the data? The next step described in the guidelines is how to add covariates/predictors to predict class membership using the three-step approach (Vermunt, 2010. Lastly, it described what essentials to report in the paper. Conclusions: When applying LGMM/LCGA models for the first time, the guidelines presented can be used to guide what models to run and what to report.

  13. Do Stress Trajectories Predict Mortality in Older Men? Longitudinal Findings from the VA Normative Aging Study

    Directory of Open Access Journals (Sweden)

    Carolyn M. Aldwin

    2011-01-01

    Full Text Available We examined long-term patterns of stressful life events (SLE and their impact on mortality contrasting two theoretical models: allostatic load (linear relationship and hormesis (inverted U relationship in 1443 NAS men (aged 41–87 in 1985; M = 60.30, SD = 7.3 with at least two reports of SLEs over 18 years (total observations = 7,634. Using a zero-inflated Poisson growth mixture model, we identified four patterns of SLE trajectories, three showing linear decreases over time with low, medium, and high intercepts, respectively, and one an inverted U, peaking at age 70. Repeating the analysis omitting two health-related SLEs yielded only the first three linear patterns. Compared to the low-stress group, both the moderate and the high-stress groups showed excess mortality, controlling for demographics and health behavior habits, HRs = 1.42 and 1.37, ps <.01 and <.05. The relationship between stress trajectories and mortality was complex and not easily explained by either theoretical model.

  14. Qualitative to quantitative: linked trajectory of method triangulation in a study on HIV/AIDS in Goa, India.

    Science.gov (United States)

    Bailey, Ajay; Hutter, Inge

    2008-10-01

    With 3.1 million people estimated to be living with HIV/AIDS in India and 39.5 million people globally, the epidemic has posed academics the challenge of identifying behaviours and their underlying beliefs in the effort to reduce the risk of HIV transmission. The Health Belief Model (HBM) is frequently used to identify risk behaviours and adherence behaviour in the field of HIV/AIDS. Risk behaviour studies that apply HBM have been largely quantitative and use of qualitative methodology is rare. The marriage of qualitative and quantitative methods has never been easy. The challenge is in triangulating the methods. Method triangulation has been largely used to combine insights from the qualitative and quantitative methods but not to link both the methods. In this paper we suggest a linked trajectory of method triangulation (LTMT). The linked trajectory aims to first gather individual level information through in-depth interviews and then to present the information as vignettes in focus group discussions. We thus validate information obtained from in-depth interviews and gather emic concepts that arise from the interaction. We thus capture both the interpretation and the interaction angles of the qualitative method. Further, using the qualitative information gained, a survey is designed. In doing so, the survey questions are grounded and contextualized. We employed this linked trajectory of method triangulation in a study on the risk assessment of HIV/AIDS among migrant and mobile men. Fieldwork was carried out in Goa, India. Data come from two waves of studies, first an explorative qualitative study (2003), second a larger study (2004-2005), including in-depth interviews (25), focus group discussions (21) and a survey (n=1259). By employing the qualitative to quantitative LTMT we can not only contextualize the existing concepts of the HBM, but also validate new concepts and identify new risk groups.

  15. Chronic exposure of grandparents to poverty and body mass index trajectories of grandchildren: a prospective intergenerational study.

    Science.gov (United States)

    Li, Miao

    2015-02-01

    In this study, I used the growth curve model to examine the association between grandparents' (first generation (G1)) life-course exposure to chronic poverty and grandchildren's (third generation (G3)) body mass index (BMI; weight (kg)/height (m)(2)) growth trajectories. This association was estimated separately for male and female grandchildren. Analyses were based on prospective data from a US longitudinal survey, the Panel Study of Income Dynamics (1968-2011), and 2 of its supplemental studies: the Child Development Supplement (1997-2011) and the Transition into Adulthood Study (1997-2011). A prospectively enrolled nationally representative cohort of 2,613 G3 youth (1,323 male, 1,290 female) sampled in the 2 supplemental studies was linked to 1,719 grandparents from the Panel Study of Income Dynamics core sample. Chronic exposure to poverty among grandparents was prospectively ascertained annually over a 30-year period prior to the collection of data on grandchildren. Findings suggested that grandparents' chronic poverty exposure was positively associated with the slope of the BMI trajectory among granddaughters (β = 0.10, 95% confidence interval: 0.03, 0.17) but not among grandsons (β = 0.02, 95% confidence interval: -0.04, 0.08). The association between grandparents' chronic poverty exposure and granddaughters' BMI growth slope remained even after controlling for parental (second generation (G2)) socioeconomic status and BMI.

  16. Segmenting Trajectories by Movement States

    NARCIS (Netherlands)

    Buchin, M.; Kruckenberg, H.; Kölzsch, A.; Timpf, S.; Laube, P.

    2013-01-01

    Dividing movement trajectories according to different movement states of animals has become a challenge in movement ecology, as well as in algorithm development. In this study, we revisit and extend a framework for trajectory segmentation based on spatio-temporal criteria for this purpose. We adapt

  17. Numerical Study on the Particle Trajectory Tracking in a Micro-UV Bio-Fluorescence Sensor.

    Science.gov (United States)

    Byeon, Sun-Seok; Cho, Moon-Young; Lee, Jong-Chul; Kim, Youn-Jea

    2015-03-01

    A micro-UV bio-fluorescence sensor was developed to detect primary biological aerosols including bacteria, bacterial spores, fungal spores, pollens, viruses, algae, etc. In order to effectively detect the bio-particles in a micro-UV bio-fluorescence sensor, numerical calculations were performed to adjust for appropriate flow conditions of the sensor by regulating the sample aerosols and sheath flow. In particular, a CFD-based model of hydrodynamic processes was developed by computing the trajectory of particles using commercially available ANSYS CFX-14 software and the Lagrangian tracking model. The established model was evaluated with regard to the variation of sheath flow rate and particle size. Results showed that the sheath flow was changed rapidly at the end of nozzle tip, but the sample particles moved near the center of aerosol jet for aerodynamic focusing with little deviation from the axis.

  18. HCO+ dissociation in a strong laser field: An ab initio classical trajectory study

    Science.gov (United States)

    Lee, Suk Kyoung; Li, Wen; Bernhard Schlegel, H.

    2012-05-01

    We have investigated the photodissociation of HCO+ in a strong field with a wavelength of 10 μm using ab initio molecular dynamics. Classical trajectories were calculated at three field intensities. At 2.9 × 1014 W/cm2 and phase ϕ = 0, protons have two distinct dissociation times, mainly due to the reorientation of HCO+ relative to the field direction prior to dissociation. The kinetic energy distribution at this intensity agrees with Wardlaw's wagging tail model, suggesting that dissociation occurs through barrier-suppression. At 1.7 × 1014 and 8.8 × 1013 W/cm2, barrier suppression is incomplete and the maximum kinetic energy is less than predicted by the wagging tail model.

  19. Forecasting Public Transit Use by Crowdsensing and Semantic Trajectory Mining: Case Studies

    Directory of Open Access Journals (Sweden)

    Ningyu Zhang

    2016-09-01

    Full Text Available With the growing development of smart cities, public transit forecasting has begun to attract significant attention. In this paper, we propose an approach for forecasting passenger boarding choices and public transit passenger flow. Our prediction model is based on mining common user behaviors for semantic trajectories and enriching features using knowledge from geographic and weather data. All the experimental data comes from the Ridge Nantong Limited bus company and Alibaba platform which is also open to the public. We evaluate our approach using various data sources, including point of interest (POI, weather condition, and public bus information in Guangzhou to demonstrate its effectiveness. Experimental results show that our proposal performs better than baselines in the prediction of passenger boarding choices and public transit passenger flow.

  20. Successful Aging: Multiple Trajectories and Population Heterogeneity

    OpenAIRE

    Fengyan Tang

    2014-01-01

    Following Rowe and Kahn¡¯s successful aging model, this study identified successful aging as a distinctive aging trajectory and examined gender differences in the aging process. Using the Health and Retirement Study data (2000-2008), this study applied group-based trajectory analysis to identify multiple aging trajectories in a sample of older Americans aged 65 and over (N=9,226). Six dimensions were analyzed in the multi-trajectory model: chronic disease, physical functional limitation, disa...

  1. Bayesian hierarchical piecewise regression models: a tool to detect trajectory divergence between groups in long-term observational studies.

    Science.gov (United States)

    Buscot, Marie-Jeanne; Wotherspoon, Simon S; Magnussen, Costan G; Juonala, Markus; Sabin, Matthew A; Burgner, David P; Lehtimäki, Terho; Viikari, Jorma S A; Hutri-Kähönen, Nina; Raitakari, Olli T; Thomson, Russell J

    2017-06-06

    Bayesian hierarchical piecewise regression (BHPR) modeling has not been previously formulated to detect and characterise the mechanism of trajectory divergence between groups of participants that have longitudinal responses with distinct developmental phases. These models are useful when participants in a prospective cohort study are grouped according to a distal dichotomous health outcome. Indeed, a refined understanding of how deleterious risk factor profiles develop across the life-course may help inform early-life interventions. Previous techniques to determine between-group differences in risk factors at each age may result in biased estimate of the age at divergence. We demonstrate the use of Bayesian hierarchical piecewise regression (BHPR) to generate a point estimate and credible interval for the age at which trajectories diverge between groups for continuous outcome measures that exhibit non-linear within-person response profiles over time. We illustrate our approach by modeling the divergence in childhood-to-adulthood body mass index (BMI) trajectories between two groups of adults with/without type 2 diabetes mellitus (T2DM) in the Cardiovascular Risk in Young Finns Study (YFS). Using the proposed BHPR approach, we estimated the BMI profiles of participants with T2DM diverged from healthy participants at age 16 years for males (95% credible interval (CI):13.5-18 years) and 21 years for females (95% CI: 19.5-23 years). These data suggest that a critical window for weight management intervention in preventing T2DM might exist before the age when BMI growth rate is naturally expected to decrease. Simulation showed that when using pairwise comparison of least-square means from categorical mixed models, smaller sample sizes tended to conclude a later age of divergence. In contrast, the point estimate of the divergence time is not biased by sample size when using the proposed BHPR method. BHPR is a powerful analytic tool to model long-term non

  2. Trajectories of delinquency and parenting styles

    NARCIS (Netherlands)

    Hoeve, M.; Blokland, A.; Dubas, J.S.; Loeber, R.; Gerris, J.R.M.; Laan, P.H. van der

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering

  3. Trajectories of Delinquency and Parenting Styles

    NARCIS (Netherlands)

    Hoeve, M.; Blokland, A.; Dubas, J.S.; Loeber, R.; Gerris, J.R.M.; Laan, P.H. van der

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering

  4. Trajectories of Delinquency and Parenting Styles

    NARCIS (Netherlands)

    Hoeve, M.; Blokland, A.; Dubas, J.S.; Loeber, R.; Gerris, J.R.M.; Laan, P.H. van der

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering

  5. Trajectories of delinquency and parenting styles

    NARCIS (Netherlands)

    M. Hoeve; A. van Blokland; J.S. Dubas; R Loeber; J.R.M. Gerris; P.H. van der Laan

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering

  6. Classical and quantum studies of the photodissociation of a HX (X=Cl,F) molecule adsorbed on ice.

    Science.gov (United States)

    Woittequand, S; Duflot, D; Monnerville, M; Pouilly, B; Toubin, C; Briquez, S; Meyer, H-D

    2007-10-28

    The photodissociation dynamics of a HX (X = Cl,F) molecule adsorbed on a hexagonal ice surface at T = 0 K is studied using time-dependent quantum wave packets and quasiclassical trajectories. The relevant potential energy surfaces are calculated using high-level ab initio methods. We present here two dimensional calculations for the dynamics of the hydrogen photofragment for both HCl and HF molecules. The purpose of this paper is to compare the photodissociation dynamics of the two molecules which are adsorbed on the ice surface with different equilibrium geometries. The total photodissociation cross section and the angular distribution are calculated. The comparison with classical trajectory calculations provides evidence for typical quantum effects and reveals rainbow structures.

  7. Childhood chronic-kidney-disease: a longitudinal-qualitative study of families learning to share management early in the trajectory.

    Science.gov (United States)

    Swallow, Veronica; Lambert, Heather; Clarke, Charlotte; Campbell, Steve; Jacoby, Ann

    2008-11-01

    To explore the ways families learn to share management during the early stages of childhood chronic-kidney-disease. This longitudinal, descriptive study based on the tenets of grounded theory, aimed to derive meaning about family-professional interactions during shared management. Data were obtained from six newly referred families, four renal nurses, four paediatric nephrologists and one dietician through: 36 semi-structured interviews, 21 case-note reviews and four child/parent learning diaries. Three learning stages were identified: dependent (families' understanding was superficial, they lacked underlying knowledge and were totally reliant on professional guidance); co-dependent (families engaged competently in management but still required extensive guidance); independent (families communicated effectively with staff and competently adjusted management within professionally defined parameters). Five families actively shared management from early in the trajectory and progressed to independent learning when, by mutual agreement, professional input to management gradually decreased. The remaining family adopted a passive approach to management, did not progress to independent learning and remained reliant on professional input. Families in this study demonstrated three learning stages in becoming competent at management. Future research is needed to investigate the ways professionals promote family competence early in the trajectory and the factors that can facilitate or hinder families' progression to independent learning.

  8. Influence of psychosocial risk factors on the trajectory of mental health problems from childhood to adolescence: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Fatori Daniel

    2013-01-01

    Full Text Available Abstract Background Longitudinal epidemiological studies involving child/adolescent mental health problems are scarce in developing countries, particularly in regions characterized by adverse living conditions. We examined the influence of psychosocial factors on the trajectory of child/adolescent mental health problems (CAMHP over time. Methods A population-based sample of 6- to 13-year-olds with CAMHP was followed-up from 2002–2003 (Time 1/T1 to 2007–2008 (Time 2/T2, with 86 out of 124 eligible children/adolescents at T1 being reassessed at T2 (sample loss: 30.6%. Outcome: CAMHP at T2 according to the Child Behavior Checklist/CBCL’s total problem scale. Psychosocial factors: T1 variables (child/adolescent’s age, family socioeconomic status; trajectory of variables from T1 to T2 (child/adolescent exposure to severe physical punishment, mother exposure to severe physical marital violence, maternal anxiety/depression; and T2 variables (maternal education, child/adolescent’s social support and pro-social activities. Results Multivariate analysis identified two risk factors for child/adolescent MHP at T2: aggravation of child/adolescent physical punishment and aggravation of maternal anxiety/depression. Conclusions The current study shows the importance of considering child/adolescent physical punishment and maternal anxiety/depression in intervention models and mental health care policies.

  9. Zeno Paradox for Bohmian Trajectories: The Unfolding of the Metatron

    CERN Document Server

    de Gosson, Maurice

    2010-01-01

    We study an analogue of the quantum Zeno paradox for the Bohm trajectory of a sharply located particle (or a system of particles). We show that a continuously observed Bohm trajectory is the classical trajectory predicted by Hamiltonian mechanics.

  10. Trajectory grouping structure

    Directory of Open Access Journals (Sweden)

    Maike Buchin

    2015-03-01

    Full Text Available The collective motion of a set of moving entities like people, birds, or other animals, is characterized by groups arising, merging, splitting, and ending. Given the trajectories of these entities, we define and model a structure that captures all of such changes using the Reeb graph, a concept from topology. The trajectory grouping structure has three natural parameters that allow more global views of the data in group size, group duration, and entity inter-distance. We prove complexity bounds on the maximum number of maximal groups that can be present, and give algorithms to compute the grouping structure efficiently. We also study how the trajectory grouping structure can be made robust, that is, how brief interruptions of groups can be disregarded in the global structure, adding a notion of persistence to the structure. Furthermore, we showcase the results of experiments using data generated by the NetLogo flocking model and from the Starkey project. The Starkey data describe the movement of elk, deer, and cattle. Although there is no ground truth for the grouping structure in this data, the experiments show that the trajectory grouping structure is plausible and has the desired effects when changing the essential parameters. Our research provides the first complete study of trajectory group evolvement, including combinatorial,algorithmic, and experimental results.

  11. Nonadiabatic nuclear dynamics of the ammonia cation studied by surface hopping classical trajectory calculations

    Science.gov (United States)

    Belyaev, Andrey K.; Domcke, Wolfgang; Lasser, Caroline; Trigila, Giulio

    2015-03-01

    The Landau-Zener (LZ) type classical-trajectory surface-hopping algorithm is applied to the nonadiabatic nuclear dynamics of the ammonia cation after photoionization of the ground-state neutral molecule to the excited states of the cation. The algorithm employs a recently proposed formula for nonadiabatic LZ transition probabilities derived from the adiabatic potential energy surfaces. The evolution of the populations of the ground state and the two lowest excited adiabatic states is calculated up to 200 fs. The results agree well with quantum simulations available for the first 100 fs based on the same potential energy surfaces. Three different time scales are detected for the nuclear dynamics: Ultrafast Jahn-Teller dynamics between the excited states on a 5 fs time scale; fast transitions between the excited state and the ground state within a time scale of 20 fs; and relatively slow partial conversion of a first-excited-state population to the ground state within a time scale of 100 fs. Beyond 100 fs, the adiabatic electronic populations are nearly constant due to a dynamic equilibrium between the three states. The ultrafast nonradiative decay of the excited-state populations provides a qualitative explanation of the experimental evidence that the ammonia cation is nonfluorescent.

  12. Nonadiabatic nuclear dynamics of the ammonia cation studied by surface hopping classical trajectory calculations

    CERN Document Server

    Belyaev, Andrey K; Lasser, Caroline; Trigila, Giulio

    2014-01-01

    The Landau--Zener (LZ) type classical-trajectory surface-hopping algorithm is applied to the nonadiabatic nuclear dynamics of the ammonia cation after photoionization of the ground-state neutral molecule to the excited states of the cation. The algorithm employs the recently proposed formula for nonadiabatic LZ transition probabilities derived from the adiabatic potential energy surfaces. The evolution of the populations of the ground state and the two lowest excited adiabatic states is calculated up to 200 fs. The results agree well with quantum simulations available for the first 100 fs based on the same potential energy surfaces. Four different time scales are detected for the nuclear dynamics: Ultrafast Jahn--Teller dynamics between the excited states on a 5 fs time scale; fast transitions between the excited state and the ground state within a time scale of 20 fs; relatively slow partial conversion of a first-excited-state population to the ground state within a time scale of 100 fs; and nearly constant ...

  13. Risk perception and the economic crisis: a longitudinal study of the trajectory of perceived risk.

    Science.gov (United States)

    Burns, William J; Peters, Ellen; Slovic, Paul

    2012-04-01

    We conducted a longitudinal survey of public response to the economic crisis to understand the trajectory of risk perception amidst an ongoing crisis. A nation-wide panel responded to seven surveys beginning in late September 2008 at the peak of the crisis and concluded in October 2009. At least 600 respondents participated in each survey, with 413 completing all seven surveys. Our online survey focused on perceptions of risk (savings, investments, retirement, job), negative emotions toward the financial crisis (sadness, anxiety, fear, anger, worry, stress), confidence in national leaders to manage the crisis (President Obama, Congress, Treasury Secretary, business leaders), and belief in one's ability to realize personal objectives despite the crisis. We employed latent growth curve modeling to analyze change in risk perception throughout the crisis. Our results suggest that, in general, people's perceptions of risk appear to decrease most rapidly during the initial phase of a crisis and then begin to level off. Negative emotion about the crisis was the most predictive of increased risk perception, supporting the notion of risk as feelings. Belief in one's ability to realize personal objectives was also predictive. Confidence in national leaders, however, was not predictive of perceived risk. Finally, our results demonstrate that groups may experience a crisis differently depending on a combination of personal characteristics such as gender, income, numeracy, and political attitude. Risk management and communication should work in sync with these mechanisms and differences across groups.

  14. Theoretical study of stereodynamics for the reaction O(aP) +D2 (v = 0, j = 0) → OD+D and isotope effect

    Institute of Scientific and Technical Information of China (English)

    Xu Zeng-Hui; Zong Fu-Jian

    2011-01-01

    Quasi-classical trajectory (QCT) calculations have been performed to study the product polarization behaviours in the reaction O(3P) + D2 (v = 0, j = 0) → OD + D. By running trajectories on the 3A' and 3A" potential energy surfaces (PESs), vector correlations such as the distributions of the polarization-dependent differential cross sections (PDDCSs), the angular distributions of P(θr) and P(φr) are presented. Isotope effect is discussed in this work by a comprehensive comparison with the reaction O(3P) + H2 (v = 0, j = 0) → H + H. Common characteristics as well as differences are discussed in product alignment and orientation for the two reactions. The isotope mass effect differs on the two potential energy surfaces: the isotope mass effect has stronger influence on P(θr) and PDDCSs of the 3A' PES while the opposite on P(φr) of the 3A" potential energy surface.

  15. Calculating TMDs of a large nucleus: Quasi-classical approximation and quantum evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kovchegov, Yuri V., E-mail: kovchegov.1@osu.edu [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Sievert, Matthew D., E-mail: msievert@bnl.gov [Bldg. 510A, Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-02-15

    We set up a formalism for calculating transverse-momentum-dependent parton distribution functions (TMDs) of a large nucleus using the tools of saturation physics. By generalizing the quasi-classical Glauber–Gribov–Mueller/McLerran–Venugopalan approximation to allow for the possibility of spin–orbit coupling, we show how any TMD can be calculated in the saturation framework. This can also be applied to the TMDs of a proton by modeling it as a large “nucleus.” To illustrate our technique, we calculate the quark TMDs of an unpolarized nucleus at large-x: the unpolarized quark distribution and the quark Boer–Mulders distribution. We observe that spin–orbit coupling leads to mixing between different TMDs of the nucleus and of the nucleons. We then consider the evolution of TMDs: at large-x, in the double-logarithmic approximation, we obtain the Sudakov form factor. At small-x the evolution of unpolarized-target quark TMDs is governed by BK/JIMWLK evolution, while the small-x evolution of polarized-target quark TMDs appears to be dominated by the QCD Reggeon.

  16. Calculating TMDs of an Unpolarized Target: Quasi-Classical Approximation and Quantum Evolution

    CERN Document Server

    Kovchegov, Yuri V

    2016-01-01

    We set up a formalism for calculating transverse-momentum-dependent parton distribution functions (TMDs) using the tools of saturation physics. By generalizing the quasi-classical Glauber-Gribov-Mueller/McLerran-Venugopalan approximation to allow for the possibility of spin-orbit coupling, we show how any TMD can be calculated in the saturation framework. This can also be applied to the TMDs of a proton by modeling it as a large "nucleus." To illustrate our technique, we calculate the quark TMDs of an unpolarized nucleus at large-x: the unpolarized quark distribution and the quark Boer-Mulders distribution. We observe that spin-orbit coupling leads to mixing between different TMDs of the nucleus and of the nucleons. We then consider the evolution of TMDs: at large-x, in the double-logarithmic approximation, we obtain the Sudakov form factor. At small-x the evolution of unpolarized-target quark TMDs is governed by BK/JIMWLK evolution, while the small-x evolution of polarized-target quark TMDs appears to be dom...

  17. Employment trajectory as determinant of change in health-related lifestyle: the prospective HeSSup study

    National Research Council Canada - National Science Library

    Virtanen, Pekka; Vahtera, Jussi; Broms, Ulla; Sillanmäki, Lauri; Kivimäki, Mika; Koskenvuo, Markku

    2008-01-01

    .... Associations of the employment trajectories with changes in smoking, alcohol drinking, body weight, physical activity and sleep duration were assessed with analysis of variance for repeated measures...

  18. Understanding Resilience and Other Trajectories of Psychological Distress: a Mixed-Methods Study of Low-Income Mothers Who Survived Hurricane Katrina.

    Science.gov (United States)

    Lowe, Sarah R; Rhodes, Jean E; Waters, Mary C

    2015-09-01

    Recent longitudinal studies in the aftermath of natural disasters have shown that resilience, defined as a trajectory of consistently low symptoms, is the modal experience, although other trajectories representing adverse responses, including chronic or delayed symptom elevations, occur in a substantial minority of survivors. Although these studies have provided insight into the prototypical patterns of postdisaster mental health, the factors that account for these patterns remain unclear. In the current analysis, we aimed to fill this gap through a mixed-methods study of female participants in the Resilience in Survivors of Katrina (RISK) study. Latent class growth analysis identified six trajectories of psychological distress in the quantitative sample (n=386). Qualitative analysis of in-depth interviews with 54 participants identified predisaster, disaster-related and postdisaster experiences that could account for the trends in the quantitative data. In particular, preexisting and gains in psychosocial resources (e.g., emotion regulation, religiosity) and positive postdisaster impacts (e.g., greater neighborhood satisfaction, improved employment opportunities) were found to underlie resilience and other positive mental health outcomes. Conversely, experiences of childhood trauma, and pre and postdisaster stressors (e.g., difficulties in intimate partner relationships) were common among participants in trajectories representing adverse psychological responses. Illustrative case studies that exemplify each trajectory are presented. The results demonstrate the utility of mixed-methods analysis to provide a richer picture of processes underlying postdisaster mental health.

  19. The role of river trajectories and channel recovery potential within sustainable river management: some case studies from southern Italy

    Science.gov (United States)

    Rosskopf, Carmen Maria; Scorpio, Vittoria; Patrizio Ciro Aucelli, Pietro

    2016-04-01

    ongoing narrowing. The assessment of evolutionary trajectories and current states of the study reaches coupled with the analysis of their connectivity at the reach to basin scale, has allowed to identify the reaches whose recovery potential and/or good ecological values maximizes the likelihood of success of future river restoration interventions. Nevertheless, as the study highlights, the widespread anthropization of river segments, including/connected to the study reaches, has to be taken in account. Therefore, any attempt to promote their natural dynamics and channel recovery, has to be accurately assessed in the framework of sustainable and risk-reduced river management according to implemented basin plans and other territorial constraints. Conversely, the obtained knowledge on the present status of river reaches and their potential near-future changes is fundamental in considering revising actual basin plans and/or programming monitoring activities.

  20. Negative events in childhood predict trajectories of internalizing symptoms up to young adulthood: an 18-year longitudinal study.

    Directory of Open Access Journals (Sweden)

    Maria Melchior

    Full Text Available Common negative events can precipitate the onset of internalizing symptoms. We studied whether their occurrence in childhood is associated with mental health trajectories over the course of development.Using data from the TEMPO study, a French community-based cohort study of youths, we studied the association between negative events in 1991 (when participants were aged 4-16 years and internalizing symptoms, assessed by the ASEBA family of instruments in 1991, 1999, and 2009 (n = 1503. Participants' trajectories of internalizing symptoms were estimated with semi-parametric regression methods (PROC TRAJ. Data were analyzed using multinomial regression models controlled for participants' sex, age, parental family status, socio-economic position, and parental history of depression.Negative childhood events were associated with an increased likelihood of concurrent internalizing symptoms which sometimes persisted into adulthood (multivariate ORs associated with > = 3 negative events respectively: high and decreasing internalizing symptoms: 5.54, 95% CI: 3.20-9.58; persistently high internalizing symptoms: 8.94, 95% CI: 2.82-28.31. Specific negative events most strongly associated with youths' persistent internalizing symptoms included: school difficulties (multivariate OR: 5.31, 95% CI: 2.24-12.59, parental stress (multivariate OR: 4.69, 95% CI: 2.02-10.87, serious illness/health problems (multivariate OR: 4.13, 95% CI: 1.76-9.70, and social isolation (multivariate OR: 2.24, 95% CI: 1.00-5.08.Common negative events can contribute to the onset of children's lasting psychological difficulties.

  1. Trajectories of sleep changes during the acute phase of traumatic brain injury: A 7-day actigraphy study

    Directory of Open Access Journals (Sweden)

    Hsiao-Yean Chiu

    2013-09-01

    Conclusion: Poor sleep efficiency and longer sleep duration are common symptoms in acute TBI patients. Both head injury severity and age predicted the trajectories of daytime and 24-hour sleep duration during the acute phase of TBI, whereas gender predicted the trajectories of 24-hour sleep duration in the mild TBI subgroup.

  2. Weight trajectories through infancy and childhood and risk of non-alcoholic fatty liver disease in adolescence: the ALSPAC study.

    Science.gov (United States)

    Anderson, Emma L; Howe, Laura D; Fraser, Abigail; Callaway, Mark P; Sattar, Naveed; Day, Chris; Tilling, Kate; Lawlor, Debbie A

    2014-09-01

    Adiposity is a key risk factor for NAFLD. Few studies have examined prospective associations of infant and childhood adiposity with subsequent NAFLD risk. We examined associations of weight-for-height trajectories from birth to age 10 with liver outcomes in adolescence, and assessed the extent to which associations are mediated through fat mass at the time of outcome assessment. Individual trajectories of weight and height were estimated for participants in the Avon Longitudinal Study of Parents and Children using random-effects linear-spline models. Associations of birthweight (adjusted for birth length) and weight change (adjusted for length/height change) from 0-3 months, 3 months-1 y, 1-3 y, 3-7 y, and 7-10 y with ultrasound scan (USS) determined liver fat and stiffness, and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) at mean age 17.8 y were assessed with linear and logistic regressions. Mediation by concurrent fat mass was assessed with adjustment for fat mass at mean age 17.8 y. Birth weight was positively associated with liver stiffness and negatively with ALT and AST. Weight change from birth to 1 y was not associated with outcomes. Weight change from 1-3 y, 3-7 y, and 7-10 y was consistently positively associated with USS and blood-based liver outcomes. Adjusting for fat mass at mean age 17.8 y attenuated associations toward the null, suggesting associations are largely mediated by concurrent body fatness. Greater rates of weight-for-height change between 1 y and 10 y are consistently associated with adverse liver outcomes in adolescence. These associations are largely mediated through concurrent fatness. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  3. Galileo's Trajectory with Mild Resistance

    Science.gov (United States)

    Groetsch, C. W.

    2012-01-01

    An aspect of Galileo's classical trajectory that persists in a simple resistance model is noted. The resistive model provides a case study for the classroom analysis of limiting behaviour of an implicitly defined function. (Contains 1 note.)

  4. State-specific tunneling lifetimes from classical trajectories: H-atom dissociation in electronically excited pyrrole

    Science.gov (United States)

    Xie, Weiwei; Domcke, Wolfgang; Farantos, Stavros C.; Grebenshchikov, Sergy Yu.

    2016-03-01

    A trajectory method of calculating tunneling probabilities from phase integrals along straight line tunneling paths, originally suggested by Makri and Miller [J. Chem. Phys. 91, 4026 (1989)] and recently implemented by Truhlar and co-workers [Chem. Sci. 5, 2091 (2014)], is tested for one- and two-dimensional ab initio based potentials describing hydrogen dissociation in the 1B1 excited electronic state of pyrrole. The primary observables are the tunneling rates in a progression of bending vibrational states lying below the dissociation barrier and their isotope dependences. Several initial ensembles of classical trajectories have been considered, corresponding to the quasiclassical and the quantum mechanical samplings of the initial conditions. It is found that the sampling based on the fixed energy Wigner density gives the best agreement with the quantum mechanical dissociation rates.

  5. The role of social position and depressive symptoms in adolescence for life-course trajectories of education and work: a cohort study.

    Science.gov (United States)

    Landstedt, Evelina; Brydsten, Anna; Hammarström, Anne; Virtanen, Pekka; Almquist, Ylva B

    2016-11-18

    While a vast amount of studies confirm the social reproduction of class and status from one generation to the next, less is known about the role of health in the child generation for these processes. Research has shown that particularly mental distress in adolescence is important for future life chances. This study aimed to examine the importance of parental socioeconomic position and depressive symptoms in youth for life-course trajectories of education and labour market attachment among men and women. Based on four waves of questionnaire data from the Northern Swedish Cohort (n = 1,001), consisting of individuals born in 1965, three steps of gender-separate analyses were undertaken. First, the individual trajectories of education and labour market attachment from age 18 to 42 were mapped through sequence analysis. Second, cluster analysis was used to identify typical trajectories. Third, two indicators of parental socioeconomic position - occupational class and employment status - and depressive symptoms at age 16 were used in multinomial regression analyses to predict adult life-course trajectories. Four typical trajectories were identified for men, of which three were characterised by stable employment and various lengths of education, and the fourth reflected a more unstable situation. Among women, five trajectories emerged, characterised by more instability compared to men. Low parental occupational class and unemployment were significantly associated with a higher risk of ending up in less advantaged trajectories for men while, for women, this was only the case for occupational class. Youth levels of depressive symptoms did not significantly differ across the trajectories. This study found support for the intergenerational reproduction of social position, particularly when measured in terms of parental occupational class. Youth depressive symptoms did not show clear differences across types of trajectories, subsequently impeding such symptoms to trigger any

  6. Trajectories of physical and mental health among persons with morbid obesity and persons with COPD: a longitudinal comparative study

    Directory of Open Access Journals (Sweden)

    Bonsaksen T

    2016-04-01

    Full Text Available Tore Bonsaksen,1 May Solveig Fagermoen,2 Anners Lerdal2,3 1Department of Occupational Therapy, Prosthetics and Orthotics, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, 2Department of Nursing Science, Institute of Health and Society, Faculty of Medicine, University of Oslo, 3Department for Patient Safety and Development, Lovisenberg Diakonale Hospital, Oslo, NorwayBackground: Morbid obesity and chronic obstructive pulmonary disease (COPD are prevalent diseases associated with impaired health-related quality of life (HRQoL. Research generally indicates that persons with morbid obesity increase their HRQoL following intervention, whereas evidence of increases in HRQoL in persons with COPD is mixed. Examining the patterns of change over time instead of merely examining whether HRQoL changes will add to the knowledge in this field.Methods: A sample of persons with morbid obesity and persons with COPD was recruited from learning and mastery courses and rehabilitation centers in Norway. The data were collected by self-report questionnaires at the start of patient education and at four subsequent time points during the 1-year follow-up. HRQoL was measured with the Short Form 12, version 2, and repeated measures analysis of variance was employed in the statistical analysis.Results: Participants with morbid obesity linearly increased their physical HRQoL during the 1-year follow-up, whereas participants with COPD showed no change. None of the groups changed their mental HRQoL during follow-up. In all subdomains of HRQoL, the participants with morbid obesity showed favorable, linearly increasing trajectories across the follow-up period. Among the participants with COPD, no change patterns occurred in the subdomains of HRQoL, except for a fluctuating pattern in the mental health domain. Age, sex, and work status did not influence the trajectories of HRQoL in any of the domains.Conclusion: A more favorable trajectory

  7. The trajectory of physical and mental health from injury to 5 years after multiple trauma: a prospective, longitudinal cohort study.

    Science.gov (United States)

    Soberg, Helene L; Finset, Arnstein; Roise, Olav; Bautz-Holter, Erik

    2012-05-01

    To describe the trajectory of physical and mental health from injury to 5 years postinjury for patients with multiple trauma, and to examine predictors of recovery of physical and mental health. A prospective, longitudinal cohort study with data from injury (baseline), the return home (t1), and 1 (t2), 2 (t3), and 5 (t4) years. Hospital and community setting. Patients (N=105; mean age ± SD, 35.3±14.0y; age range, 18-67y; 83% men) with multiple trauma and a New Injury Severity Score (NISS) ≥16 treated at a regional trauma referral center. Mean NISS ± SD was 34.6±12.6, and mean Glasgow Coma Scale (GCS) score ± SD was 12.2±3.9. Not applicable. Medical Outcomes Study 36-Item Short-Form Health Survey physical component summary (PCS) and mental component summary (MCS), injury severity parameters, and World Health Organization Disability Assessment Schedule II (WHODAS II) for activities and participation. The proportion with poor physical health (women) (B=-4.24, P=.003), education (low/high) (B=3.43, P=.019), and WHODAS II cognitive function (B=.18, P<.001) and Participation in society (B=.18, P≤.001). Physical and mental health over the 5 years improved with time, but was still significantly below population means. The physical and mental health status stabilized, but the recovery trajectories differed for physical and mental health. Predictors of health were personal and injury-related factors and function in a biopsychosocial perspective. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  8. Family and neighbourhood socioeconomic inequalities in childhood trajectories of BMI and overweight: longitudinal study of Australian children.

    Directory of Open Access Journals (Sweden)

    Pauline W Jansen

    Full Text Available BACKGROUND: Socioeconomic inequalities in longitudinal patterning of childhood overweight could cause marked differentials in total burden by adulthood. This study aims to determine timing and strength of the association between socioeconomic status (SES and children's body mass index (BMI in the pre- and primary school years, and to examine socioeconomic differences in overweight trajectories across childhood. METHODS: Participants were 4949 children from the Longitudinal Study of Australian Children. BMI was measured at four biennial waves starting at age 4-5 years in 2004. Developmental trajectories of childhood overweight were identified with latent class analyses. Composite variables of family and neighbourhood SES were used. RESULTS: Socioeconomic differences in mean BMI z-scores already present at age 4-5 more than doubled by age 10-11 years, reflecting decreasing mean BMI among advantaged rather than increasing means among disadvantaged children. Latent class analysis identified children with 'stable normal weight' (68%, and with 'persistent' (15%, 'late-onset' (14%, and 'resolving' overweight (3%. Risks of persistent and late-onset childhood overweight were highest among low SES families (e.g. most disadvantaged quintile: OR(persistent = 2.51, 95%CI: 1.83-3.43, and only partly explained by birth weight and parental overweight. Relationships with neighbourhood SES were weaker and attenuated fully on adjustment for family SES. No socioeconomic gradient was observed for resolving overweight. CONCLUSIONS: Childhood has become the critical period when socioeconomic inequalities in overweight emerge and strengthen. Although targeting disadvantaged children with early overweight must be a top priority, the presence of childhood overweight even among less-disadvantaged families suggests only whole-society approaches will eliminate overweight-associated morbidity.

  9. Childhood trajectories of inattention and hyperactivity and prediction of educational attainment in early adulthood: a 16-year longitudinal population-based study.

    Science.gov (United States)

    Pingault, Jean-Baptiste; Tremblay, Richard E; Vitaro, Frank; Carbonneau, René; Genolini, Christophe; Falissard, Bruno; Côté, Sylvana M

    2011-11-01

    Literature clearly documents the association between mental health problems, particularly attention deficit hyperactivity disorder (ADHD), and educational attainment. However, inattention and hyperactivity are generally not considered independently from each other in prospective studies. The aim of the present study was to differentiate the unique, additive, or interactive contributions of inattention and hyperactivity symptoms to educational attainment. The authors randomly selected 2,000 participants from a representative sample of Canadian children and estimated developmental trajectories of inattention and hyperactivity between the ages of 6 and 12 years using yearly assessments. High school graduation status, at age 22-23 years, was obtained from official records. Four trajectories of inattention and four trajectories of hyperactivity were observed between the ages of 6 and 12 years. After controlling for hyperactivity and other confounding variables, a high inattention trajectory (compared with low inattention) strongly predicted not having a high school diploma at 22-23 years of age (odds ratio=7.66, 95% confidence interval [CI]=5.06-11.58). To a lesser extent, a declining or rising trajectory of inattention also made a significant contribution (odds ratios of 2.67 [95% CI=1.90-3.75] and 3.87 [95% CI=2.75-5.45], respectively). Hyperactivity was not a significant predictor once inattention was taken into account. Inattention rather than hyperactivity during elementary school significantly predicts long-term educational attainment. Children with attention problems, regardless of hyperactivity, need preventive intervention early in their development.

  10. Experimental study of Counter-Rotating Vortex Pair Trajectories induced by a Round Jet in Cross-Flow at Low Velocity Ratios

    CERN Document Server

    Cambonie, T; Aider, J -L

    2013-01-01

    Circular flush Jets In Cross-Flow were experimentally studied in a water tunnel using Volumetric Particle Tracking Velocimetry, for a range of jet to cross-flow velocity ratios, r, from 0.5 to 3, jet exit diameters $d$ from 0.8 cm to 1 cm and cross-flow boundary layer thickness delta from 1 to 2.5 cm. The analysis of the 3D mean velocity fields allows for the definition, computation and study of Counter-rotating Vortex Pair trajectories. The influences of r, d and delta were investigated. A new scaling based on momentum ratio r_m taking into account jet and cross-flow momentum distributions is introduced based on the analysis of jet trajectories published in the literature. Using a rigorous scaling quality factor Q to quantify how well a given scaling successfully collapses trajectories, we show that the proposed scaling also improves the collapse of CVP trajectories, leading to a final scaling law for these trajectories.

  11. Using the life course perspective to study the entry into the illness trajectory: the perspective of caregivers of people with Alzheimer's disease.

    Science.gov (United States)

    Carpentier, Normand; Bernard, Paul; Grenier, Amanda; Guberman, Nancy

    2010-05-01

    The research community is showing increasing interest in the analysis of the care trajectory of people with chronic health problems, especially dementias such as Alzheimer's disease. However, despite this interest, there is little research on the initial phases of the care trajectory. The fact that the first symptoms of dementia are generally noticed by those surrounding the elderly person suggests that the recognition of the disease is intimately linked to interactions not only amongst family members but also amongst friends, neighbours and health professionals. This study focuses on the period beginning with the first manifestations of cognitive difficulties and ending with the diagnosis of Alzheimer-type dementia. Interviews with 60 caregivers in Montreal, Canada were used to reconstruct how older people with Alzheimer-type dementia enter into the care trajectory. Our methods consisted of the analysis of social networks, social dynamics and action sequences. Our findings are presented in the form of a typology comprised of 5 pathways of entries into the care trajectory that are structured around the following four principles of the Life Course Perspective: family history, linked lives, human agency and organisational effects. We believe that analyses of the initial phases of the care trajectory, such as this one, are essential for the application of effective early detection and intervention policies. They are also central to informing future studies that seek to understand the care experience in its entirety. Crown Copyright (c) 2010. Published by Elsevier Ltd. All rights reserved.

  12. A Numerical Study of Low-Thrust Limited Power Trajectories between Coplanar Circular Orbits in an Inverse-Square Force Field

    Directory of Open Access Journals (Sweden)

    Sandro da Silva Fernandes

    2012-01-01

    Full Text Available A numerical study of optimal low-thrust limited power trajectories for simple transfer (no rendezvous between circular coplanar orbits in an inverse-square force field is performed by two different classes of algorithms in optimization of trajectories. This study is carried out by means of a direct method based on gradient techniques and by an indirect method based on the second variation theory. The direct approach of the trajectory optimization problem combines the main positive characteristics of two well-known direct methods in optimization of trajectories: the steepest-descent (first-order gradient method and a direct second variation (second-order gradient method. On the other hand, the indirect approach of the trajectory optimization problem involves two different algorithms of the well-known neighboring extremals method. Several radius ratios and transfer durations are considered, and the fuel consumption is taken as the performance criterion. For small-amplitude transfers, the results are compared to the ones provided by a linear analytical theory.

  13. Trajectories of childhood internalizing and externalizing psychopathology and psychotic-like experiences in adolescence: A prospective population-based cohort study.

    Science.gov (United States)

    Lancefield, Kristin S; Raudino, Alessandra; Downs, Johnny M; Laurens, Kristin R

    2016-05-01

    Adolescent internalizing and externalizing psychopathology is strongly associated with adult psychiatric morbidity, including psychotic disorders. This study examined whether internalizing or externalizing trajectories (continuity/discontinuity of symptoms) from middle childhood were associated with adolescent psychotic-like experiences (PLEs). Prospective data were collected from a community sample of 553 children (mean age = 10.4 years; 50% male) and their primary caregivers. Participants completed questionnaire reports of internalizing and externalizing psychopathology and PLEs at baseline, and again approximately 2 years later. Logistic regression was used to examine the association of adolescent PLEs with four trajectories of internalizing and externalizing psychopathology (persistent, incident, remitting, and none), controlling for a range of potential confounders and sampling bias. Significant associations were identified between adolescent PLEs and the incident internalizing (adjusted odds ratio [adj. OR] = 2.96; 95% confidence interval [CI] = 1.60-5.49) and externalizing psychopathology (adj. OR = 2.14; 95% CI = 1.11-4.14) trajectories, as well as the persistent internalizing (adj. OR = 1.90; 95% CI = 1.13-3.18) and externalizing (adj. OR = 1.81, 95% CI = 1.02-3.19) trajectories. Children with remitting psychopathology trajectories were no more likely to present later PLEs than those who never experienced psychopathology. While for many individuals symptoms and illness remit during development without intervention, this study provides important insights regarding potential targets and timing for delivery of early intervention and prevention programs.

  14. Exploring the Trajectory of Personal, Moral and Spiritual Values of 16- to 18-Year-Old Students Taking Religious Studies at A Level in the UK

    Science.gov (United States)

    Francis, Leslie J.; Village, Andrew; Parker, Stephen G.

    2017-01-01

    This study set out to explore the trajectory of personal, moral and spiritual values of students taking Religious Studies at A level in the UK. A sample of 150 students completed a battery of measures at the beginning of their period of A level study and again at the end. The data found no difference over this period of time in personal values…

  15. Theoretical Studies of Gas Phase Elementary Reactions

    Science.gov (United States)

    2009-11-30

    matrix propagation and the Magnus expansion of the time evolution operator. The scheme combines formally accurate quantum propagation of electrons...beginning of the N3 trajectory , and the large grey dots the conical intersections encountered. [sa(4)- CASSCF(15e/12o)/aug-cc-pVTZ level]. 3 as...photodissociation dynamics of H2CO is known to involve S1, T1 and S0. Recent quasiclassical trajectory (QCT) calculations in conjunction with

  16. An air-mass trajectory study of the transport of radioactivity from Fukushima to Thessaloniki, Greece and Milan, Italy

    Science.gov (United States)

    Ioannidou, A.; Giannakaki, E.; Manolopoulou, M.; Stoulos, S.; Vagena, E.; Papastefanou, C.; Gini, L.; Manenti, S.; Groppi, F.

    2013-08-01

    Analyses of 131I, 137Cs and 134Cs in airborne aerosols were carried out in daily samples at two different sites of investigation: Thessaloniki, Greece (40° N) and Milan, Italy (45° N) after the Fukushima accident during the period of March-April, 2011. The radionuclide concentrations were determined and studied as a function of time. The 131I concentration in air over Milan and Thessaloniki peaked on April 3-4, 2011, with observed activities 467 μBq m-3 and 497 μBq m-3, respectively. The 134Cs/137Cs activity ratio values in air were around 1 in both regions, related to the burn-up history of the damaged nuclear fuel of the destroyed nuclear reactor. The high 131I/137Cs ratio, observed during the first days after the accident, followed by lower values during the following days, reflects not only the initial release ratio but also the different volatility, attachment and removal of the two isotopes during transportation due to their different physico-chemical properties. No artificial radionuclides could be detected in air after April 28, 2011 in both regions of investigation. The different maxima of airborne 131I and 134,137Cs in these two regions were related to long-range air mass transport from Japan, across the Pacific and to Central Europe. Analysis of backward trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. HYSPLIT backward trajectories were applied for the interpretation of activity variations of measured radionuclides.

  17. Quasi-Classical Calculation of the Mixed-State Thermal Conductivity in s- and d-Wave Superconductors

    Science.gov (United States)

    Adachi, Hiroto; Miranović, Predrag; Ichioka, Masanori; Machida, Kazushige

    2007-06-01

    To see how superconducting gap structures affect the longitudinal component of mixed-state thermal conductivity κxx(B), the magnetic-field dependences of κxx(B) in s- and d-wave superconductors are investigated. Calculations are performed on the basis of the quasi-classical theory of superconductivity by fully taking account of the spatial variation of the normal Green’s function, neglected in previous works, by the Brandt-Pesch-Tewordt approximation. On the basis of our result, we discuss the possibility of κxx(B) measurement as a method of probing the gap structure.

  18. Early PTSD symptom trajectories: persistence, recovery, and response to treatment: results from the Jerusalem Trauma Outreach and Prevention Study (J-TOPS.

    Directory of Open Access Journals (Sweden)

    Isaac R Galatzer-Levy

    Full Text Available CONTEXT: Uncovering heterogeneities in the progression of early PTSD symptoms can improve our understanding of the disorder's pathogenesis and prophylaxis. OBJECTIVES: To describe discrete symptom trajectories and examine their relevance for preventive interventions. DESIGN: Latent Growth Mixture Modeling (LGMM of data from a randomized controlled study of early treatment. LGMM identifies latent longitudinal trajectories by exploring discrete mixture distributions underlying observable data. SETTING: Hadassah Hospital unselectively receives trauma survivors from Jerusalem and vicinity. PARTICIPANTS: Adult survivors of potentially traumatic events consecutively admitted to the hospital's emergency department (ED were assessed ten days and one-, five-, nine- and fifteen months after ED admission. Participants with data at ten days and at least two additional assessments (n = 957 were included; 125 received cognitive behavioral therapy (CBT between one and nine months. APPROACH: We used LGMM to identify latent parameters of symptom progression and tested the effect of CBT on these parameters. CBT consisted of 12 weekly sessions of either cognitive therapy (n = 41 or prolonged exposure (PE, n = 49, starting 29.8±5.7 days after ED admission, or delayed PE (n = 35 starting at 151.8±42.4 days. CBT effectively reduced PTSD symptoms in the entire sample. MAIN OUTCOME MEASURE: Latent trajectories of PTSD symptoms; effects of CBT on these trajectories. RESULTS: THREE TRAJECTORIES WERE IDENTIFIED: Rapid Remitting (rapid decrease in symptoms from 1- to 5-months; 56% of the sample, Slow Remitting (progressive decrease in symptoms over 15 months; 27% and Non-Remitting (persistently elevated symptoms; 17%. CBT accelerated the recovery of the Slow Remitting class but did not affect the other classes. CONCLUSIONS: The early course of PTSD symptoms is characterized by distinct and diverging response patterns that are centrally relevant to

  19. Early PTSD Symptom Trajectories: Persistence, Recovery, and Response to Treatment: Results from the Jerusalem Trauma Outreach and Prevention Study (J-TOPS)

    Science.gov (United States)

    Galatzer-Levy, Isaac R.; Ankri, Yael; Freedman, Sara; Israeli-Shalev, Yossi; Roitman, Pablo; Gilad, Moran; Shalev, Arieh Y.

    2013-01-01

    Context Uncovering heterogeneities in the progression of early PTSD symptoms can improve our understanding of the disorder's pathogenesis and prophylaxis. Objectives To describe discrete symptom trajectories and examine their relevance for preventive interventions. Design Latent Growth Mixture Modeling (LGMM) of data from a randomized controlled study of early treatment. LGMM identifies latent longitudinal trajectories by exploring discrete mixture distributions underlying observable data. Setting Hadassah Hospital unselectively receives trauma survivors from Jerusalem and vicinity. Participants Adult survivors of potentially traumatic events consecutively admitted to the hospital's emergency department (ED) were assessed ten days and one-, five-, nine- and fifteen months after ED admission. Participants with data at ten days and at least two additional assessments (n = 957) were included; 125 received cognitive behavioral therapy (CBT) between one and nine months. Approach We used LGMM to identify latent parameters of symptom progression and tested the effect of CBT on these parameters. CBT consisted of 12 weekly sessions of either cognitive therapy (n = 41) or prolonged exposure (PE, n = 49), starting 29.8±5.7 days after ED admission, or delayed PE (n = 35) starting at 151.8±42.4 days. CBT effectively reduced PTSD symptoms in the entire sample. Main Outcome Measure Latent trajectories of PTSD symptoms; effects of CBT on these trajectories. Results Three trajectories were identified: Rapid Remitting (rapid decrease in symptoms from 1- to 5-months; 56% of the sample), Slow Remitting (progressive decrease in symptoms over 15 months; 27%) and Non-Remitting (persistently elevated symptoms; 17%). CBT accelerated the recovery of the Slow Remitting class but did not affect the other classes. Conclusions The early course of PTSD symptoms is characterized by distinct and diverging response patterns that are centrally relevant to understanding the disorder

  20. Developmental trajectories of adolescent cannabis use and their relationship to young adult social and behavioural adjustment: A longitudinal study of Australian youth.

    Science.gov (United States)

    Scholes-Balog, Kirsty E; Hemphill, Sheryl A; Evans-Whipp, Tracy J; Toumbourou, John W; Patton, George C

    2016-02-01

    This study aimed to identify distinct developmental trajectories (sub-groups of individuals who showed similar longitudinal patterns) of cannabis use among Australian adolescents, and to examine associations between trajectory group membership and measures of social and behavioural adjustment in young adulthood. Participants (n=852, 53% female) were part of the International Youth Development Study. Latent class growth analysis was used to identify distinct trajectories of cannabis use frequency from average ages 12 to 19, across 6 waves of data. Logistic regression analyses and analyses of covariance were used to examine relationships between trajectory group membership and young adult (average age: 21) adjustment, controlling for a range of covariates. Three trajectories were identified: abstainers (62%), early onset users (11%), and late onset occasional users (27%). The early onset users showed a higher frequency of antisocial behaviour, violence, cannabis use, cannabis-related harms, cigarette use, and alcohol harms, compared to the abstinent group in young adulthood. The late onset occasional users reported a higher frequency of cannabis use, cannabis-related harms, illicit drug use, and alcohol harms, compared to the abstinent group in young adulthood. There were no differences between the trajectory groups on measures of employment, school completion, post-secondary education, income, depression/anxiety, or alcohol use problems. In conclusion, early onset of cannabis use, even at relatively low frequency during adolescence, is associated with poorer adjustment in young adulthood. Prevention and intervention efforts to delay or prevent uptake of cannabis use should be particularly focussed on early adolescence prior to age 12. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. A CLUSTERING OF DJA STOCKS - THE APPLICATION IN FINANCE OF A METHOD FIRST USED IN GENE TRAJECTORY STUDY

    Directory of Open Access Journals (Sweden)

    Silaghi Gheorghe Cosmin

    2009-05-01

    Full Text Available Previously we employed the Gene Trajectory Clustering methodology to search for different associations of the stocks composing the DJA index, with the aim of finding different, logic clusters, supported by economic reasons, preferably different than the

  2. Path-based Queries on Trajectory Data

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

    2014-01-01

    a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set....... To efficiently support strict path queries, we present a novel NETwork-constrained TRAjectory index (NETTRA). This index enables very efficient retrieval of trajectories that follow a specific path, i.e., strict path queries. NETTRA uses a new path encoding scheme that can determine if a trajectory follows......, consisting of 1.7 million trajectories (941 million GPS records) and a road network with 1.3 million edges, shows a speed-up of two orders of magnitude compared to state-of-the-art trajectory indexes....

  3. Study of air masses trajectories during the TRO-pico campaign aiming at studying of the impact of convective overshooting on the stratospheric water budget

    Science.gov (United States)

    Mappe, Irene; Riviere, Emmanuel; Khaykin, Sergey; Ghysels, Mélanie; Stoeffler, Clara; Amarouche, Nadir; Durry, Georges; Held, Gerhard

    2014-05-01

    Water vapor directly affects the climate as greenhouse gas emissions, but also indirectly by the formation of other essential elements of radiative forcing as aerosols, clouds of ice. In addition, water has a significant role in the chemical composition, the balance of ozone and the oxidizing capacity of the atmosphere. Transfers of water vapor in the troposphere to the stratosphere are one of the major scientific challenges in modeling the stratosphere and climate. The TRO-pico small balloon campaign took place in Bauru (22.3 ° S) in southern Brazil during two convective seasons. Its main objective was to study the exchange of water vapor between the upper troposphere and lower stratosphere, and better understand the role of overshooting convection in the moistening of the lower stratosphere and its variability at the local scale to infer a typical impact at a larger scale. Here we focus on the purely convective seasons of the campaign, with a first period in March 2012 and a second in Jan-Feb 2013, during which, in addition to convective tracers measurements (methane, O3…) H2O was intensively sampled by two different in situ hygrometers : Pico-SDLA H2O and FLASH-B. Here we investigated all the measurements gathered close to deep convective events and analyze them in term of potential signature of overshooting convection in the lower stratosphere, to put to the fore possible impact at the wet season time scale. The approach is the use of a trajectory model (HYsplit) running with the GDAS analyses, the different H2O profile from both instruments, echo top from the Bauru S-Band radar highlighting any potential overshoot occurrence in the vicinity of the balloon flight earlier during the day. For each local maximum of H2O, a back trajectory is computed from the balloon position. It is checked if the back trajectory cross an overshooting cell seen by the Bauru radar, and matches it in time and maximum altitude Here we use a total of 8 vertical profiles of H2O from

  4. The trajectory and the related physical and social determinants of body mass index in elementary school children: results from the child and adolescent behaviors in long-term evolution study.

    Science.gov (United States)

    Lin, Li-Ju; Chang, Hsing-Yi; Luh, Dih-Ling; Hurng, Baai-Shyun; Yen, Lee-Lan

    2014-01-01

    This study explored developmental trajectory patterns of BMI and associated factors. Participants included 1,609 students who were followed from age 7 to 12 years. Data collection involved annual self-administered questionnaires and records of height and weight. An ecological model was used to identify the factors associated with BMI trajectories. Group-based trajectory models and multinomial logit models were used in the statistical analysis. There were gender differences in BMI trajectories. Among boys, four BMI trajectories were normal or slightly underweight, persistently normal weight, overweight becoming obese, and persistently obese. Among girls, four BMI trajectories were persistently slightly underweight, persistently normal weight, persistently overweight, and persistently obese. The mean BMI in each trajectory group demonstrated an upward trend over time. In boys, BMI trajectories were significantly associated with after-school exercise, academic performance, family interactions, overweight parents, and father's education level. In girls, BMI trajectories were significantly associated with television viewing or computer use, family interactions, peer interactions, and overweight parents. Children under age 7 years who are already overweight or obese are an important target for interventions. The different factors associated with BMI trajectories can be used for targeting high risk groups.

  5. The Trajectory and the Related Physical and Social Determinants of Body Mass Index in Elementary School Children: Results from the Child and Adolescent Behaviors in Long-Term Evolution Study

    Directory of Open Access Journals (Sweden)

    Li-Ju Lin

    2014-01-01

    Full Text Available This study explored developmental trajectory patterns of BMI and associated factors. Participants included 1,609 students who were followed from age 7 to 12 years. Data collection involved annual self-administered questionnaires and records of height and weight. An ecological model was used to identify the factors associated with BMI trajectories. Group-based trajectory models and multinomial logit models were used in the statistical analysis. There were gender differences in BMI trajectories. Among boys, four BMI trajectories were normal or slightly underweight, persistently normal weight, overweight becoming obese, and persistently obese. Among girls, four BMI trajectories were persistently slightly underweight, persistently normal weight, persistently overweight, and persistently obese. The mean BMI in each trajectory group demonstrated an upward trend over time. In boys, BMI trajectories were significantly associated with after-school exercise, academic performance, family interactions, overweight parents, and father’s education level. In girls, BMI trajectories were significantly associated with television viewing or computer use, family interactions, peer interactions, and overweight parents. Children under age 7 years who are already overweight or obese are an important target for interventions. The different factors associated with BMI trajectories can be used for targeting high risk groups.

  6. Genetic influences on alcohol use behaviors have diverging developmental trajectories: a prospective study among male and female twins.

    Science.gov (United States)

    Meyers, Jacquelyn L; Salvatore, Jessica E; Vuoksimaa, Eero; Korhonen, Tellervo; Pulkkinen, Lea; Rose, Richard J; Kaprio, Jaakko; Dick, Danielle M

    2014-11-01

    Both alcohol-specific genetic factors and genetic factors related to externalizing behavior influence problematic alcohol use. Little is known, however, about the etiologic role of these 2 components of genetic risk on alcohol-related behaviors across development. Prior studies conducted in a male cohort of twins suggest that externalizing genetic factors are important for predicting heavy alcohol use in adolescence, whereas alcohol-specific genetic factors increase in importance during the transition to adulthood. In this report, we studied twin brothers and sisters and brother-sister twin pairs to examine such developmental trajectories and investigate whether sex and cotwin sex effects modify these genetic influences. We used prospective, longitudinal twin data collected between ages 12 and 22 within the population-based FinnTwin12 cohort study (analytic n = 1,864). Our dependent measures of alcohol use behaviors included alcohol initiation (age 12), intoxication frequency (ages 14 and 17), and alcohol dependence criteria (age 22). Each individual's genetic risk of alcohol use disorders (AUD-GR) was indexed by his/her parents' and cotwin's DSM-IV Alcohol Dependence (AD) criterion counts. Likewise, each individual's genetic risk of externalizing disorders (EXT-GR) was indexed with a composite measure of parents' and cotwin's DSM-IV Conduct Disorder and Antisocial Personality Disorder criterion counts. EXT-GR was most strongly related to alcohol use behaviors during adolescence, while AUD-GR was most strongly related to alcohol problems in young adulthood. Further, sex of the twin and sex of the cotwin significantly moderated the associations between genetic risk and alcohol use behaviors across development: AUD-GR influenced early adolescent alcohol use behaviors in females more than in males, and EXT-GR influenced age 22 AD more in males than in females. In addition, the associations of AUD-GR and EXT-GR with intoxication frequency were greater among 14- and

  7. Alcohol Use Trajectories and Problem Drinking over the Course of Adolescence: A Study of North American Indigenous Youth and Their Caretakers

    Science.gov (United States)

    Cheadle, Jacob E.; Whitbeck, Les B.

    2011-01-01

    This study investigated the links between alcohol use trajectories and problem drinking ("Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition" abuse/dependence) using five waves of data from 727 North American Indigenous adolescents between 10 and 17 years from eight reservations sharing a common language and culture.…

  8. WWC Review of the Report "Longitudinal Evaluation of a Scale-up Model for Teaching Mathematics with Trajectories and Technologies." What Works Clearinghouse Single Study Review

    Science.gov (United States)

    What Works Clearinghouse, 2014

    2014-01-01

    The 2012 study, "Longitudinal Evaluation of a Scale-Up Model for Teaching Mathematics with Trajectories and Technologies," examined the effects of "Technology-enhanced, Research-based, Instruction, Assessment, and professional Development (TRIAD)," a math intervention for preschoolers that combines a curriculum, a…

  9. L2 Academic Discourse Socialization through Oral Presentations: An Undergraduate Student's Learning Trajectory in Study Abroad

    Science.gov (United States)

    Kobayashi, Masaki

    2016-01-01

    The present study provides an in-depth, longitudinal account of an undergraduate student's L2 discourse socialization in an academic exchange program in Canada. By invoking Rogoff's (1995) notion of participatory appropriation, this qualitative case study examined an L2 student's task-related strategies and performance as they evolved over time in…

  10. Communication: Wigner functions in action-angle variables, Bohr-Sommerfeld quantization, the Heisenberg correspondence principle, and a symmetrical quasi-classical approach to the full electronic density matrix.

    Science.gov (United States)

    Miller, William H; Cotton, Stephen J

    2016-08-28

    It is pointed out that the classical phase space distribution in action-angle (a-a) variables obtained from a Wigner function depends on how the calculation is carried out: if one computes the standard Wigner function in Cartesian variables (p, x), and then replaces p and x by their expressions in terms of a-a variables, one obtains a different result than if the Wigner function is computed directly in terms of the a-a variables. Furthermore, the latter procedure gives a result more consistent with classical and semiclassical theory-e.g., by incorporating the Bohr-Sommerfeld quantization condition (quantum states defined by integer values of the action variable) as well as the Heisenberg correspondence principle for matrix elements of an operator between such states-and has also been shown to be more accurate when applied to electronically non-adiabatic applications as implemented within the recently developed symmetrical quasi-classical (SQC) Meyer-Miller (MM) approach. Moreover, use of the Wigner function (obtained directly) in a-a variables shows how our standard SQC/MM approach can be used to obtain off-diagonal elements of the electronic density matrix by processing in a different way the same set of trajectories already used (in the SQC/MM methodology) to obtain the diagonal elements.

  11. Communication: Wigner functions in action-angle variables, Bohr-Sommerfeld quantization, the Heisenberg correspondence principle, and a symmetrical quasi-classical approach to the full electronic density matrix

    Science.gov (United States)

    Miller, William H.; Cotton, Stephen J.

    2016-08-01

    It is pointed out that the classical phase space distribution in action-angle (a-a) variables obtained from a Wigner function depends on how the calculation is carried out: if one computes the standard Wigner function in Cartesian variables (p, x), and then replaces p and x by their expressions in terms of a-a variables, one obtains a different result than if the Wigner function is computed directly in terms of the a-a variables. Furthermore, the latter procedure gives a result more consistent with classical and semiclassical theory—e.g., by incorporating the Bohr-Sommerfeld quantization condition (quantum states defined by integer values of the action variable) as well as the Heisenberg correspondence principle for matrix elements of an operator between such states—and has also been shown to be more accurate when applied to electronically non-adiabatic applications as implemented within the recently developed symmetrical quasi-classical (SQC) Meyer-Miller (MM) approach. Moreover, use of the Wigner function (obtained directly) in a-a variables shows how our standard SQC/MM approach can be used to obtain off-diagonal elements of the electronic density matrix by processing in a different way the same set of trajectories already used (in the SQC/MM methodology) to obtain the diagonal elements.

  12. Ground Based Studies of Gas-Liquid Flows in Microgravity Using Learjet Trajectories

    Science.gov (United States)

    Bousman, W. S.; Dukler, A. E.

    1994-01-01

    A 1.27 cm diameter two phase gas-liquid flow experiment has been developed with the NASA Lewis Research Center to study two-phase flows in microgravity. The experiment allows for the measurement of void fraction, pressure drop, film thickness and bubble and wave velocities as well as for high speed photography. Three liquids were used to study the effects of liquid viscosity and surface tension, and flow pattern maps are presented for each. The experimental results are used to develop mechanistically based models to predict void fraction, bubble velocity, pressure drop and flow pattern transitions in microgravity.

  13. 10-year trajectories of depressive symptoms and risk of dementia: a population-based study

    NARCIS (Netherlands)

    S.S. Mirza (Saira); F.J. Wolters (Frank J.); S.A. Swanson (Sonja A.); P.J. Koudstaal (Peter Jan); A. Hofman (Albert); H.W. Tiemeier (Henning); M.K. Ikram (Kamran)

    2016-01-01

    textabstractBackground Late-life depressive symptoms have been extensively studied for their relationship with incident dementia, but have been typically assessed at a single timepoint. Such an approach neglects the course of depression, which, given its remitting and relapsing nature, might provide

  14. Intrauterine Cannabis Exposure Affects Fetal Growth Trajectories: The Generation R Study

    Science.gov (United States)

    El Marroun, Hanan; Tiemeier, Henning; Steegers, Eric A. P.; Jaddoe, Vincent W. V.; Hofman, Albert; Verhulst, Frank C.; van den Brink, Wim; Huizink, Anja C.

    2009-01-01

    Objective: Cannabis is the most commonly consumed illicit drug among pregnant women. Intrauterine exposure to cannabis may result in risks for the developing fetus. The importance of intrauterine growth on subsequent psychological and behavioral child development has been demonstrated. This study examined the relation between maternal cannabis use…

  15. Intrauterine Cannabis Exposure Affects Fetal Growth Trajectories: The Generation R Study

    Science.gov (United States)

    El Marroun, Hanan; Tiemeier, Henning; Steegers, Eric A. P.; Jaddoe, Vincent W. V.; Hofman, Albert; Verhulst, Frank C.; van den Brink, Wim; Huizink, Anja C.

    2009-01-01

    Objective: Cannabis is the most commonly consumed illicit drug among pregnant women. Intrauterine exposure to cannabis may result in risks for the developing fetus. The importance of intrauterine growth on subsequent psychological and behavioral child development has been demonstrated. This study examined the relation between maternal cannabis use…

  16. Motion in action: A study of second graders' trajectories of experience during guided inquiry science instruction

    Science.gov (United States)

    Hapgood, Susanna Elizabeth

    This interpretive case study describes a 10-day inquiry science program of study of motion down inclined planes during which a class of 21 second graders investigated scientific relationships such as mass and speed, speed and momentum, and mass and momentum via both text-based experiences ("second-hand investigations") and hands-on materials-based experiments ("first-hand investigations"). Data sources included over 11 hours of videotaped instruction in addition to children's written work, class-generated artifacts, and paper-and-pencil pre- and posttests. Content analyses informed by both sociocultural and developmental perspectives revealed that, in addition to a significant increase in pre- to posttest scores, children in the class engaged in several processes integral to inquiry, namely, (a) using data as evidence, (b) evaluating investigative procedures, and (c) making sense of multiple forms of representations. In addition, the study describes the range of and shifts in children's ideas about scientific relationships fundamental to developing an understanding of motion. Many children were observed to make causal attributions involving a relationship between two variables, such as the mass and momentum of a ball rolling down a ramp. Discussed are mediating factors such as the teacher's role in scaffolding the class's investigations and features of the innovative "scientists' notebook" texts, which were integral to the instruction. Also presented is evidence of first-hand and second-hand investigations working in concert to provide the elementary school students with rich opportunities to learn and to express their developing understandings of scientific ideas. This study provides a rare glimpse of primary-grade inquiry-based science instruction within a classroom context.

  17. Do dietary trajectories between infancy and toddlerhood influence IQ in childhood and adolescence? Results from a prospective birth cohort study.

    Directory of Open Access Journals (Sweden)

    Lisa G Smithers

    Full Text Available We examined whether trajectories of dietary patterns from 6 to 24 months of age are associated with intelligence quotient (IQ in childhood and adolescence.Participants were children enrolled in a prospective UK birth cohort (n = 7,652 who had IQ measured at age 8 and/or 15 years. Dietary patterns were previously extracted from questionnaires when children were aged 6, 15 and 24 months using principal component analysis. Dietary trajectories were generated by combining scores on similar dietary patterns across each age, using multilevel mixed models. Associations between dietary trajectories and IQ were examined in generalized linear models with adjustment for potential confounders.Four dietary pattern trajectories were constructed from 6 to 24 months of age and were named according to foods that made the strongest contribution to trajectory scores; Healthy (characterised by breastfeeding at 6 months, raw fruit and vegetables, cheese and herbs at 15 and 24 months; Discretionary (biscuits, chocolate, crisps at all ages, Traditional (meat, cooked vegetables and puddings at all ages and, Ready-to-eat (use of ready-prepared baby foods at 6 and 15 months, biscuits, bread and breakfast cereals at 24 months. In fully-adjusted models, a 1 SD change in the Healthy trajectory was weakly associated with higher IQ at age 8 (1.07 (95%CI 0.17, 1.97 but not 15 years (0.49 (-0.28, 1.26. Associations between the Discretionary and Traditional trajectories with IQ at 8 and 15 years were as follows; Discretionary; 8 years -0.35(-1.03, 0.33, 15 years -0.73(-1.33, -0.14 Traditional; 8 years -0.19(-0.71, 0.3315 years -0.41(-0.77, -0.04. The Ready-to-eat trajectory had no association with IQ at either age (8 years 0.32(-4.31, 4.95, 15 years 1.11(-3.10, 5.33.The Discretionary and Traditional dietary pattern trajectories from 6 to 24 months of age, over the period when food patterns begin to emerge, are weakly associated with IQ in adolescence.

  18. Trajectories of abstinence-induced Internet gaming withdrawal symptoms: A prospective pilot study

    Directory of Open Access Journals (Sweden)

    Dean Kaptsis

    2016-12-01

    Full Text Available Internet Gaming Disorder (IGD is positioned in the appendix of the DSM-5 as a condition requiring further study. The IGD criteria refer to withdrawal symptoms, including irritability, anxiety, or sadness, that follow cessation of Internet gaming (APA, 2013. The aim of this study was to prospectively examine the nature of Internet gaming withdrawal symptoms, if they occur, under gaming abstinence conditions. This study employed a repeated-measures protocol to examine the cognitive-affective reactions of participants undertaking an 84-h Internet gaming abstinence period. The sample included individuals who met the IGD criteria as well as those who regularly played Internet games but did not meet the IGD criteria. Outcome variables included affect (positive and negative, psychological distress (depression, anxiety, stress, and Internet gaming withdrawal symptoms (craving/urge, thoughts about gaming, inability to resist gaming. A total of 24 participants (Mage = 24.6 years, SD = 5.8 were recruited from online gaming communities, and completed a series of online surveys before, during, and after abstaining from Massively Multiplayer Online (MMO games. Both the IGD group and the non-IGD group experienced an abstinence-induced decline in withdrawal symptomatology, negative affect, and psychological distress. The IGD group experienced its largest decline in withdrawal symptomatology within the first 24 h of abstinence. These preliminary data suggest that gaming withdrawal symptoms may follow, at least initially, negative linear and quadratic trends. Further prospective work in larger samples involving longer periods of abstinence is required to verify and expand upon these observations.

  19. Trajectories of growth and symptoms of attention-deficit/hyperactivity disorder in children: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Kajantie Eero

    2011-10-01

    Full Text Available Abstract Background Empirical evidence suggests that prenatal growth is associated with attention deficit/hyperactivity disorder (ADHD and its symptoms. Data on the importance of postnatal growth is, however scanty. We studied whether pre- and postnatal growth up to 56 months is associated with symptoms of ADHD in children. Method A longitudinal regional birth cohort study comprising 893 children followed up to 56 months. The associations between pre- and postnatal growth and parent-rated ADHD symptoms of the child were analyzed with multiple linear regression analyses and repeated-measures analyzes of covariance. Results Children born lighter, thinner, shorter, and with a smaller head circumference, adjusted for length of gestation, received higher parent-rated ADHD symptoms scores at 56 months. Further, smaller head circumference throughout the period of growth from birth up to 56 months was related to higher ADHD symptoms scores. The associations changed only little after adjusting for several pre- and neonatal factors. The associations were not modified by sex and there were no evidence of non-linear associations. Conclusions Slower prenatal growth in weight, body-mass index, length, and head circumference may pose a risk for higher ADHD symptoms in childhood. The consistently smaller head circumference from birth up to 56 months characterizing children with higher ADHD symptoms may point to a lack of catch-up growth in head circumference in childhood as a predisposing factor.

  20. Study of the pion trajectory in the photoproduction of leading neutrons at HERA

    CERN Document Server

    Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; D'Agostini, Giulio; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fricke, U; Fusayasu, T; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Gliga, S; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Grigorescu, G; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, M; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lainesse, J; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Notz, D; Nowak, R J; Nuncio, A E; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Palmonari, F; Parenti, A; Park, I H; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Rinaldi, L; Riveline, U; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J

    2004-01-01

    Energetic neutrons produced in ep collisions at HERA have been studied with the ZEUS detector in the photoproduction regime at a mean photon-proton center-of-mass energy of 220 GeV. The neutrons carry a large fraction 0.6 < x_L < 0.925 of the incoming proton energy and the four-momentum-transfer squared at the proton-neutron vertex is small, |t| < 0.425 GeV^2. The x_L distribution of the neutrons is measured in bins of t. The (1-x_L) distributions in the bins of t studied satisfy a power law dN/dx_L ~ (1-x_L)^a(t), with the powers a(t) following a linear function of t: a(t) = 1.08 +/- 0.08(stat.) +0.15/-0.28(syst.) - [2.78 +/- 0.32(stat.) +0.51/-0.47(syst.) GeV^-2]t. This result is consistent with the expectations of pion-exchange models, in which the incoming proton fluctuates to a neutron-pion state and the electron interacts with the pion.

  1. Trajectory of phantom limb pain relief using mirror therapy: Retrospective analysis of two studies.

    Science.gov (United States)

    Griffin, Sarah C; Curran, Sean; Chan, Annie W Y; Finn, Sacha B; Baker, Chris I; Pasquina, Paul F; Tsao, Jack W

    2017-04-01

    Research indicates that mirror therapy reduces phantom limb pain (PLP). Objectives were to determine when mirror therapy works in those who respond to treatment, the relevance of baseline PLP to when pain relief occurs, and what pain symptoms respond to mirror therapy. Data from two independent cohorts with unilateral lower limb amputation were analyzed for this study (n=33). Mirror therapy consisted of 15-min sessions in which amputees performed synchronous movements of the phantom and intact legs/feet. PLP was measured using a visual analogue scale and the Short-Form McGill Pain Questionnaire. The severity of PLP at the beginning of treatment predicted when pain relief occurred. Those with low baseline PLP experienced a reduction (pMirror therapy reduced throbbing, shooting, stabbing, sharp, cramping, aching, tender, splitting, tiring/exhausting, and punishing-cruel pain symptoms. The degree of PLP at baseline predicts when mirror therapy relieves pain. This article indicates that the degree of baseline PLP affects when mirror therapy relieves pain: relief occurs by session 7 in patients with low PLP but by session 21 in patients with high PLP. Clinicians should anticipate slower pain relief in patients who begin treatment with high levels of pain. ClinicalTrials.gov numbers:NCT00623818 and NCT00662415. Copyright © 2017 Scandinavian Association for the Study of Pain. All rights reserved.

  2. A Study on Decoding Models for the Reconstruction of Hand Trajectories from the Human Magnetoencephalography

    Directory of Open Access Journals (Sweden)

    Hong Gi Yeom

    2014-01-01

    Full Text Available Decoding neural signals into control outputs has been a key to the development of brain-computer interfaces (BCIs. While many studies have identified neural correlates of kinematics or applied advanced machine learning algorithms to improve decoding performance, relatively less attention has been paid to optimal design of decoding models. For generating continuous movements from neural activity, design of decoding models should address how to incorporate movement dynamics into models and how to select a model given specific BCI objectives. Considering nonlinear and independent speed characteristics, we propose a hybrid Kalman filter to decode the hand direction and speed independently. We also investigate changes in performance of different decoding models (the linear and Kalman filters when they predict reaching movements only or predict both reach and rest. Our offline study on human magnetoencephalography (MEG during point-to-point arm movements shows that the performance of the linear filter or the Kalman filter is affected by including resting states for training and predicting movements. However, the hybrid Kalman filter consistently outperforms others regardless of movement states. The results demonstrate that better design of decoding models is achieved by incorporating movement dynamics into modeling or selecting a model according to decoding objectives.

  3. Gut microbiota trajectory in patients with severe burn: A time series study.

    Science.gov (United States)

    Wang, Xinying; Yang, Jianbo; Tian, Feng; Zhang, Li; Lei, Qiucheng; Jiang, Tingting; Zhou, Jihong; Yuan, Siming; Wang, Jun; Feng, Zhijian; Li, Jieshou

    2017-08-12

    This time series experiments aimed to investigate the dynamic change of gut microbiomes after severe burn and its association with enteral nutrition (EN). Seven severely burned patients who suffered from a severe metal dust explosion injury were recruited in this study. The dynamic changes of gut microbiome of fecal samples at six time points (1-3days, 2, 3, 4, 5 and 6weeks after severe burn) were detected using 16S ribosomal RNA pyrosequencing technology. Following the post-burn temporal order, gut microbiota dysbiosis was detected in the gut microbiome after severe burn, then it was gradually resolved. The bio-diversity of gut bacteria was initially decreased, and then returned to normal level. In addition, at the early stage (from 2 to 4weeks), the majority of those patients' gut microbiome were opportunistic pathogen genus, Enterococcus and Escherichia; while at the end of this study, the majority was a beneficial genus, Bacteroides. EN can promote the recovery of gut microbiota, especially in EN well-tolerated patients. Severe burn injury can cause a dramatic dysbiosis of gut microbiota. A trend of enriched beneficial bacteria and diminished opportunistic pathogen bacteria may serve as prognosis microbiome biomarkers of severe burn patients. Copyright © 2017. Published by Elsevier Inc.

  4. Collective variables for the study of long-time kinetics from molecular trajectories: theory and methods.

    Science.gov (United States)

    Noé, Frank; Clementi, Cecilia

    2017-04-01

    Collective variables are an important concept to study high-dimensional dynamical systems, such as molecular dynamics of macromolecules, liquids, or polymers, in particular to define relevant metastable states and state-transition or phase-transition. Over the past decade, a rigorous mathematical theory has been formulated to define optimal collective variables to characterize slow dynamical processes. Here we review recent developments, including a variational principle to find optimal approximations to slow collective variables from simulation data, and algorithms such as the time-lagged independent component analysis. Using these concepts, a distance metric can be defined that quantifies how slowly molecular conformations interconvert. Extensions and open questions are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Growing up with Asperger’s syndrome: developmental trajectory of autobiographical memory (a clinical case study

    Directory of Open Access Journals (Sweden)

    Laetitia eBon

    2013-01-01

    Full Text Available Autobiographical memory and social cognition share common properties and both are affected in autism spectrum disorders (ASD. So far, most of the scant research in ASD has concerned adults, systematically reporting impairment of the episodic component. The only study to be conducted with children concluded that they have poorer personal semantic knowledge than typical developing children. The present study explores the development of both components of autobiographical memory in an 8-year-old boy diagnosed with Asperger’s syndrome, based on three examinations in 2007, 2008 and 2010. On each occasion, he underwent a general neuropsychological assessment including theory of mind tasks, and a specially-designed autobiographical memory task allowing us to test both the semantic and the episodic components for three lifetime periods (current year, previous year and earlier years. We observed difficulties in strategic retrieval and theory of mind, with a significant improvement between the second and third examinations. Regarding autobiographical memory, different patterns of performance were noted in all three examinations: 1 relative preservation of current-year personal knowledge, but impairment for the previous and earlier years, and 2 impairment of episodic memory for the current and previous year, but performances similar to those of controls for the earlier years. The first pattern can be explained by abnormal forgetting and by the semanticization mechanism, which needs verbal communication and social interaction to be efficient. The second pattern suggests that the development of episodic memory only reached the stage of event memory. This term refers to memory for personal events lacking in details or spatiotemporal specificity, and is usually observed in children younger than 5. We conclude that the abnormal functioning of social cognition in ASD, encompassing social and personal points of view, has an impact on both components of

  6. Trajectories of legitimate peripheral participation: Ethnographic case studies of learning ecology

    Science.gov (United States)

    Bowen, Gervase Michael Reynolds

    1999-09-01

    Current reform documents in education call for elementary and high school students to engage in "authentic" scientific practices. In the past several years a number of authors have suggested that science education research and curriculum development could benefit from insights gained by research in the social studies of science that documents and theorizes science as it is actually done. Yet, although practices of laboratory science are well understood and provide a foundation from which educational practices could be drawn, little is known about the practices of the science disciplines which deal with field research and how people are enculturated into those practices. This dissertation is constituted by a series of research papers on different (although inter-related) topics, in which I examine the enculturation into the practices of field ecology and the world-view that is associated with that enculturation. To better understand the practices of field ecology and how they develop, I conducted several projects: (i) a video ethnography of a second-year university ecology class and observations on research experiences undergraduates experience; (ii) ethnographic research with ecologists conducting field research; (iii) observations of graduate student and professional ecologists as they participated in conferences, engaged in interaction in their laboratory and social settings, and presented/discussed their findings in various settings; (iv) interviews with graduate student and professional ecologists discussing their field research experiences; (v) videotaped interviews with practicing researchers and under/graduate science and non-science students as they interpreted various ecology-related inscriptions; (vi) an analysis of the inscriptions and textual information present in the various texts (textbooks and journals) used to teach students about ecology; and, (vii) observations of elementary school students engaged in practices congruent with those of field

  7. Investigation of scaling properties of a thin current sheet by means of particle trajectories study

    CERN Document Server

    Sasunov, Yu L; Alexeev, I I; Belenkaya, E S; Semenov, V S; Kubyshkin, I V; Mingalev, O V

    2015-01-01

    A thin current sheet (TCS), with the width of an order of thermal proton gyroradius, appears a fundamental physical object which plays an important role in structuring of major magnetospheric current systems (magnetotail, magnetodisk, etc.). The TCSs are nowadays under extensive study by means of space missions and theoretical models. We consider a simple model of the TCS separating two half-spaces occupied by a homogenous magnetic field of opposite sign tangential to the TCS; a small normal component of the magnetic field is prescribed. An analytical solution for the electric current and plasma density in the close vicinity of the TCS has been obtained and compared with numerical simulation. The number density and the electric current profiles have two maxima each. The characteristic spatial scale $z_S$ of the maxima location was investigated as a function of initial pitch-angle of an incoming charge particle. The effect of the thermal dispersion of the incoming proton beam have been taken into consideration...

  8. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China.

    Science.gov (United States)

    Chen, Jianglong; Gao, Jinlong; Yuan, Feng

    2016-01-01

    Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing's shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China.

  9. Service Use and Unmet Needs in Youth Suicide: A Study of Trajectories

    Science.gov (United States)

    Renaud, Johanne; Séguin, Monique; Lesage, Alain D; Marquette, Claude; Choo, Bettina; Turecki, Gustavo

    2014-01-01

    Objective: While 90% of suicide victims have suffered from mental health disorders, less than one-half are in contact with a mental health professional in the year preceding their death. Service use in the last year of life of young suicide victims and control subjects was studied in Quebec. We wanted to determine what kinds of health care services were needed and if they were actually received by suicide victims. Method: We recruited 67 consecutive suicide victims and 56 matched living control subjects (aged 25 years and younger). We evaluated subjects’ psychopathological profile and determined which services would have been indicated by conducting a needs assessment. We then compared this with what services were actually received. Results: Suicide victims were more likely than living control subjects to have a psychiatric diagnosis. They were most in need of services to address substance use disorder, depression, interpersonal distress, and suicide-related problems. There were significant deficits in the domains of coordination and continuity of care, mental health promotion and training, and governance. Conclusions: Our results show that we need to urgently take action to address these identified deficits to prevent further loss of life in our young people. PMID:25565685

  10. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China.

    Directory of Open Access Journals (Sweden)

    Jianglong Chen

    Full Text Available Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing's shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China.

  11. Design study of double-layer beam trajectory accelerator based on the Rhodotron structure

    Science.gov (United States)

    Jabbari, Iraj; Poursaleh, Ali Mohammad; Khalafi, Hossein

    2016-08-01

    In this paper, the conceptual design of a new structure of industrial electron accelerator based on the Rhodotron accelerator is presented and its properties are compared with those of Rhodotron-TT200 accelerator. The main goal of this study was to reduce the power of RF system of accelerator at the same output electron beam energy. The main difference between the new accelerator structure with the Rhodotron accelerator is the length of the coaxial cavity that is equal to the wavelength at the resonant frequency. Also two sets of bending magnets were used around the acceleration cavity in two layers. In the new structure, the beam crosses several times in the coaxial cavity by the bending magnets around the cavity at the first layer and then is transferred to the second layer using the central bending magnet. The acceleration process in the second layer is similar to the first layer. Hence, the energy of the electron beam will be doubled. The electrical power consumption of the RF system and magnet system were calculated and simulated for the new accelerator structure and TT200. Comparing the calculated and simulated results of the TT200 with those of experimental results revealed good agreement. The results showed that the overall electrical power consumption of the new accelerator structure was less than that of the TT200 at the same energy and power of the electron beam. As such, the electrical efficiency of the new structure was improved.

  12. Design study of double-layer beam trajectory accelerator based on the Rhodotron structure

    Energy Technology Data Exchange (ETDEWEB)

    Jabbari, Iraj, E-mail: i_jabbari@ast.ui.ac.ir [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 8174673441 (Iran, Islamic Republic of); Poursaleh, Ali Mohammad [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 8174673441 (Iran, Islamic Republic of); Central Iran Research Complex, NSTRI, Yazd (Iran, Islamic Republic of); Khalafi, Hossein [Central Iran Research Complex, NSTRI, Yazd (Iran, Islamic Republic of)

    2016-08-21

    In this paper, the conceptual design of a new structure of industrial electron accelerator based on the Rhodotron accelerator is presented and its properties are compared with those of Rhodotron-TT200 accelerator. The main goal of this study was to reduce the power of RF system of accelerator at the same output electron beam energy. The main difference between the new accelerator structure with the Rhodotron accelerator is the length of the coaxial cavity that is equal to the wavelength at the resonant frequency. Also two sets of bending magnets were used around the acceleration cavity in two layers. In the new structure, the beam crosses several times in the coaxial cavity by the bending magnets around the cavity at the first layer and then is transferred to the second layer using the central bending magnet. The acceleration process in the second layer is similar to the first layer. Hence, the energy of the electron beam will be doubled. The electrical power consumption of the RF system and magnet system were calculated and simulated for the new accelerator structure and TT200. Comparing the calculated and simulated results of the TT200 with those of experimental results revealed good agreement. The results showed that the overall electrical power consumption of the new accelerator structure was less than that of the TT200 at the same energy and power of the electron beam. As such, the electrical efficiency of the new structure was improved.

  13. Trajectory dynamics study of the Ar + CH4 dissociation reaction at high temperatures: the importance of zero-point-energy effects.

    Science.gov (United States)

    Marques, J M C; Martínez-Núñez, E; Fernandez-Ramos, A; Vazquez, S A

    2005-06-23

    Large-scale classical trajectory calculations have been performed to study the reaction Ar + CH4--> CH3 +H + Ar in the temperature range 2500 energy surface used for ArCH4 is the sum of the nonbonding pairwise potentials of Hase and collaborators (J. Chem. Phys. 2001, 114, 535) that models the intermolecular interaction and the CH4 intramolecular potential of Duchovic et al. (J. Phys. Chem. 1984, 88, 1339), which has been modified to account for the H-H repulsion at small bending angles. The thermal rate coefficient has been calculated, and the zero-point energy (ZPE) of the CH3 product molecule has been taken into account in the analysis of the results; also, two approaches have been applied for discarding predissociative trajectories. In both cases, good agreement is observed between the experimental and trajectory results after imposing the ZPE of CH3. The energy-transfer parameters have also been obtained from trajectory calculations and compared with available values estimated from experiment using the master equation formalism; in general, the agreement is good.

  14. Identifying patients with advanced chronic conditions for a progressive palliative care approach: a cross-sectional study of prognostic indicators related to end-of-life trajectories

    Science.gov (United States)

    Amblàs-Novellas, J; Murray, S A; Espaulella, J; Martinez-Muñoz, M; Blay, C; Gómez-Batiste, X

    2016-01-01

    Objectives 2 innovative concepts have lately been developed to radically improve the care of patients with advanced chronic conditions (PACC): early identification of palliative care (PC) needs and the 3 end-of-life trajectories in chronic illnesses (acute, intermittent and gradual dwindling). It is not clear (1) what indicators work best for this early identification and (2) if specific clinical indicators exist for each of these trajectories. The objectives of this study are to explore these 2 issues. Setting 3 primary care services, an acute care hospital, an intermediate care centre and 4 nursing homes in a mixed urban–rural district in Barcelona, Spain. Participants 782 patients (61.5% women) with a positive NECPAL CCOMS-ICO test, indicating they might benefit from a PC approach. Outcome measures The characteristics and distribution of the indicators of the NECPAL CCOMS-ICO tool are analysed with respect to the 3 trajectories and have been arranged by domain (functional, nutritional and cognitive status, emotional problems, geriatric syndromes, social vulnerability and others) and according to their static (severity) and dynamic (progression) properties. Results The common indicators associated with early end-of-life identification are functional (44.3%) and nutritional (30.7%) progression, emotional distress (21.9%) and geriatric syndromes (15.7% delirium, 11.2% falls). The rest of the indicators showed differences in the associations per illness trajectories (ppalliative approach. PMID:27645556

  15. The dissociative chemisorption of methane on Ni(100) and Ni(111): classical and quantum studies based on the reaction path Hamiltonian.

    Science.gov (United States)

    Mastromatteo, Michael; Jackson, Bret

    2013-11-21

    Electronic structure methods based on density functional theory are used to construct a reaction path Hamiltonian for CH4 dissociation on the Ni(100) and Ni(111) surfaces. Both quantum and quasi-classical trajectory approaches are used to compute dissociative sticking probabilities, including all molecular degrees of freedom and the effects of lattice motion. Both approaches show a large enhancement in sticking when the incident molecule is vibrationally excited, and both can reproduce the mode specificity observed in experiments. However, the quasi-classical calculations significantly overestimate the ground state dissociative sticking at all energies, and the magnitude of the enhancement in sticking with vibrational excitation is much smaller than that computed using the quantum approach or observed in the experiments. The origin of this behavior is an unphysical flow of zero point energy from the nine normal vibrational modes into the reaction coordinate, giving large values for reaction at energies below the activation energy. Perturbative assumptions made in the quantum studies are shown to be accurate at all energies studied.

  16. Mental health trajectories from childhood to young adulthood affect the educational and employment status of young adults: results from the TRAILS study.

    Science.gov (United States)

    Veldman, Karin; Reijneveld, Sijmen A; Ortiz, Josue Almansa; Verhulst, Frank C; Bültmann, Ute

    2015-06-01

    Young adults at work without basic educational level (BEL), and young adults in Neither Employment, Education nor Training (NEET) are at high risk of adverse employment outcomes. Evidence lacks on the impact of mental health problems during childhood, adolescence and young adulthood on employment outcomes of young adults. Therefore, the aims of this study were to (1) identify trajectories of mental health problems from childhood to young adulthood and (2) investigate the relation between these trajectories and the educational or employment status of young adults. Data were used from the Tracking Adolescents' Individual Lives Survey (TRAILS), a Dutch prospective cohort study with 9-year follow-up. Trajectories of mental health problems measured at ages 11, 13.5, 16 and 19 years were identified in 1711 young adults with latent class growth models. Young adults with high-stable trajectories of total problems, from childhood to young adulthood, were more likely to work without BEL or be in NEET at age 19, than to be at school or to work with BEL (28.0% vs 16.0%, p=0.01). The same was found for externalising problems (35.3% vs 23.2%, p=0.02). For internalising and attention problems, no statistically significant differences were found. Young adults with high-stable trajectories of mental health problems from age 11 to 19, were at risk of adverse employment outcomes. Interventions reducing mental health problems in childhood may improve the educational or employment status of young adults and their chances for successfully entering the labour market. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. Toward a new understanding of legacy of early attachments for future antisocial trajectories: evidence from two longitudinal studies.

    Science.gov (United States)

    Kochanska, Grazyna; Kim, Sanghag

    2012-08-01

    Early parent-child attachment has been extensively explored as a contributor to children's future adaptive or antisocial outcomes, but the specific developmental mechanisms remain to be fully understood. We examined long-term indirect developmental sequelae of early security in two longitudinal community samples followed from infancy to early school age: the Family Study (102 mothers, fathers, and infants) and the Parent-Child Study (112 mothers and infants). Constructs at multiple levels (child characteristics, parent-child security, parental discipline, and child antisocial outcomes) were assessed using a range of methods (extensive behavioral observations in a variety of settings, informants' ratings). Both studies supported the proposed model of infant attachment as a potent catalyst that moderates future developmental socialization trajectories, despite having few long-term main effects. In insecure dyads, a pattern of coercion emerged between children who were anger prone as toddlers and their parents, resulting in parents' increased power-assertive discipline. Power assertion in turn predicted children's rule-breaking conduct and a compromised capacity to delay in laboratory paradigms, as well as oppositional, disruptive, callous, and aggressive behavior rated by parents and teachers at early school age. This causal chain was absent in secure dyads, where child anger proneness was unrelated to power assertion, and power assertion was unrelated to antisocial outcomes. Early insecurity appeared to act as a catalyst for the parent-child dyad embarking on a mutually adversarial path toward antisocial outcomes, whereas security defused such a maladaptive dynamic. The possible mechanisms of those effects were proposed.

  18. Trajectories in parallel optics.

    Science.gov (United States)

    Klapp, Iftach; Sochen, Nir; Mendlovic, David

    2011-10-01

    In our previous work we showed the ability to improve the optical system's matrix condition by optical design, thereby improving its robustness to noise. It was shown that by using singular value decomposition, a target point-spread function (PSF) matrix can be defined for an auxiliary optical system, which works parallel to the original system to achieve such an improvement. In this paper, after briefly introducing the all optics implementation of the auxiliary system, we show a method to decompose the target PSF matrix. This is done through a series of shifted responses of auxiliary optics (named trajectories), where a complicated hardware filter is replaced by postprocessing. This process manipulates the pixel confined PSF response of simple auxiliary optics, which in turn creates an auxiliary system with the required PSF matrix. This method is simulated on two space variant systems and reduces their system condition number from 18,598 to 197 and from 87,640 to 5.75, respectively. We perform a study of the latter result and show significant improvement in image restoration performance, in comparison to a system without auxiliary optics and to other previously suggested hybrid solutions. Image restoration results show that in a range of low signal-to-noise ratio values, the trajectories method gives a significant advantage over alternative approaches. A third space invariant study case is explored only briefly, and we present a significant improvement in the matrix condition number from 1.9160e+013 to 34,526.

  19. Opposite Drug Prescription and Cost Trajectories following Integrative and Conventional Care for Pain – A Case-Control Study

    Science.gov (United States)

    Sundberg, Tobias; Petzold, Max; Kohls, Niko; Falkenberg, Torkel

    2014-01-01

    Objectives Pharmacotherapy may have a limited role in long-term pain management. Comparative trajectories of drug prescriptions and costs, two quality-of-care indicators for pain conditions, are largely unknown subsequent to conventional or integrative care (IC) management. The objectives of this study were to compare prescribed defined daily doses (DDD) and cost of first line drugs for pain patients referred to conventional or anthroposophic IC in Stockholm County, Sweden. Methods In this retrospective high quality registry case-control study, IC and conventional care patients were identified through inpatient care registries and matched on pain diagnosis (ICD-10: M79), age, gender and socio-demographics. National drug registry data was used to investigate changes in DDD and costs from 90/180 days before, to 90/180 days after, index visits to IC and conventional care. The primary selected drug category was analgesics, complemented by musculo-skeletal system drugs (e.g. anti-inflammatories, muscle relaxants) and psycholeptics (e.g. hypnotics, sedatives). Results After index care visits, conventional care pain patients (n = 1050) compared to IC patients (n = 213), were prescribed significantly more analgesics. The average (95% CI) group difference was 15.2 (6.0 to 24.3), p = 0.001, DDD/patient after 90 days; and 21.5 (7.4 to 35.6), p = 0.003, DDD/patient after 180 days. The cost of the prescribed and sold analgesics was significantly higher for conventional care after 90 days: euro/patient 10.7 (1.3 to 20.0), p = 0.025. Changes in drug prescription and costs for the other drug categories were not significantly different between groups. Conclusions Drug prescriptions and costs of analgesics increased following conventional care and decreased following IC, indicating potentially fewer adverse drug events and beneficial societal cost savings with IC. PMID:24827981

  20. Long-Term Trajectories of Health-Related Quality of Life in Individuals With Cerebral Palsy : A Multicenter Longitudinal Study

    NARCIS (Netherlands)

    Tan, Siok Swan; van Meeteren, Jetty; Ketelaar, Marjolijn; Schuengel, Carlo; Reinders - Messelink, Heelen; Raat, Hein; Dallmeijer, Annet J.; Roebroeck, Marij E.

    2014-01-01

    Objectives: To (1) determine the long-term trajectory of health-related quality of life (HRQOL) for the dimensions of physical complaints and motor, psychological, and social functioning for groups of individuals with cerebral palsy (CP) aged 1 to 24 years; (2) assess the variability in HRQOL within

  1. Lunar and interplanetary trajectories

    CERN Document Server

    Biesbroek, Robin

    2016-01-01

    This book provides readers with a clear description of the types of lunar and interplanetary trajectories, and how they influence satellite-system design. The description follows an engineering rather than a mathematical approach and includes many examples of lunar trajectories, based on real missions. It helps readers gain an understanding of the driving subsystems of interplanetary and lunar satellites. The tables and graphs showing features of trajectories make the book easy to understand. .

  2. Trajectory P system

    Institute of Scientific and Technical Information of China (English)

    Subbaiah Annadurai; Thiyagarajan Kalyani; Vincent Rajkumar Dare; Durairaj Gnanaraj Thomas

    2008-01-01

    Membrane computing is a branch of natural computing aiming to abstract computing ideas for the structure and the functioning of living cells as well as from the way the cells are organized in tissues or higher-order structures.Trajectories are used as a tool for modeling language operations and other related objects.A trajectory P system consists of a membrane structure in which the object in each membrane is a collection of words and the evolutionary rules are given in terms of trajectories.In this paper,we present some properties of trajectory P systems.

  3. Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study

    DEFF Research Database (Denmark)

    Tabák, A.G.; Jokela, M.; Akbaraly, T.N.

    2009-01-01

    BACKGROUND: Little is known about the timing of changes in glucose metabolism before occurrence of type 2 diabetes. We aimed to characterise trajectories of fasting and postload glucose, insulin sensitivity, and insulin secretion in individuals who develop type 2 diabetes. METHODS: We analysed data...... from our prospective occupational cohort study (Whitehall II study) of 6538 (71% male and 91% white) British civil servants without diabetes mellitus at baseline. During a median follow-up period of 9.7 years, 505 diabetes cases were diagnosed (49.1% on the basis of oral glucose tolerance test). We...... assessed retrospective trajectories of fasting and 2-h postload glucose, homoeostasis model assessment (HOMA) insulin sensitivity, and HOMA beta-cell function from up to 13 years before diabetes diagnosis (diabetic group) or at the end of follow-up (non-diabetics). FINDINGS: Multilevel models adjusted...

  4. Dynamical Convergence Trajectory in Networks

    Institute of Scientific and Technical Information of China (English)

    TAN Ning; ZHANG Yun-Jun; OUYANG Qi; GENG Zhi

    2005-01-01

    @@ It is well known that topology and dynamics are two major aspects to determine the function of a network. We study one of the dynamic properties of a network: trajectory convergence, i.e. how a system converges to its steady state. Using numerical and analytical methods, we show that in a logical-like dynamical model, the occurrence of convergent trajectory in a network depends mainly on the type of the fixed point and the ratio between activation and inhibition links. We analytically proof that this property is induced by the competition between two types of state transition structures in phase space: tree-like transition structure and star-like transition structure. We show that the biological networks, such as the cell cycle network in budding yeast, prefers the tree-like transition structures and suggest that this type of convergence trajectories may be universal.

  5. Theoretical study of stereodynamics for the O(3P) + H2 → OH + H reaction

    Institute of Scientific and Technical Information of China (English)

    Liu Shi-Li; Shi Ying

    2011-01-01

    This paper employs the quasi-classical trajectory calculations to study the influence of collision energy on the title A 2000 104 2308). It calculates the product angular distribution of P(θr), P(φr) and P(θr, φr) which reflects vector correlation. The distribution P(θr) shows that product rotational angular momentum vectors j' of the products are strongly aligned along the relative velocity direction k. The distribution of P(φr) implies a preference for left-handed product rotation in planes parallel to the scattering plane. Four different polarisation-dependent cross-sections are also presented in the centre-of-mass frame. Results indicate that OH is sensitively affected by collision energies of H2.

  6. Classical trajectories and quantum tunneling

    CERN Document Server

    Ivlev, B I

    2003-01-01

    The problem of inter-band tunneling in a semiconductor (Zener breakdown) in a nonstationary and homogeneous electric field is solved exactly. Using the exact analytical solution, the approximation based on classical trajectories is studied. A new mechanism of enhanced tunneling through static non-one-dimensional barriers is proposed in addition to well known normal tunneling solely described by a trajectory in imaginary time. Under certain conditions on the barrier shape and the particle energy, the probability of enhanced tunneling is not exponentially small even for non-transparent barriers, in contrast to the case of normal tunneling.

  7. Trajectory similarity join in spatial networks

    KAUST Repository

    Shang, Shuo

    2017-09-07

    The matching of similar pairs of objects, called similarity join, is fundamental functionality in data management. We consider the case of trajectory similarity join (TS-Join), where the objects are trajectories of vehicles moving in road networks. Thus, given two sets of trajectories and a threshold θ, the TS-Join returns all pairs of trajectories from the two sets with similarity above θ. This join targets applications such as trajectory near-duplicate detection, data cleaning, ridesharing recommendation, and traffic congestion prediction. With these applications in mind, we provide a purposeful definition of similarity. To enable efficient TS-Join processing on large sets of trajectories, we develop search space pruning techniques and take into account the parallel processing capabilities of modern processors. Specifically, we present a two-phase divide-and-conquer algorithm. For each trajectory, the algorithm first finds similar trajectories. Then it merges the results to achieve a final result. The algorithm exploits an upper bound on the spatiotemporal similarity and a heuristic scheduling strategy for search space pruning. The algorithm\\'s per-trajectory searches are independent of each other and can be performed in parallel, and the merging has constant cost. An empirical study with real data offers insight in the performance of the algorithm and demonstrates that is capable of outperforming a well-designed baseline algorithm by an order of magnitude.

  8. 平面磁力研磨轨迹的研究与分析%Study and analysis on plane magnetic abrasive trajectory

    Institute of Scientific and Technical Information of China (English)

    焦安源; 邹艳华

    2011-01-01

    In this paper, complex polishing trajectory of magnetic brush has been modified and studied by use of newly designed experiment device. The results show the surface roughness and precision can be elevated, and the homogeneity of section shape can also be improved in improving process. In addition, the magnetic abrasive finishing results can be predicted by the theoretical analysis on polishing trajectory of magnetic brush.%利用自行设计的试验装置,改善了磁力刷的研磨轨迹.结果表明:改善磁力刷研磨轨迹后,不仅可以减小表面粗糙度值、提高平面精度,还改善了研磨截面微观形状均匀性.另外,可通过采取理论分析的方法对研磨效果进行预测.

  9. Access, Coping and Relevance of Education at Local Level: A Case Study. A life course approach to the analysis of young people’s educational trajectories

    Directory of Open Access Journals (Sweden)

    Silvia Demozzi

    2016-07-01

    Full Text Available The present paper introduces the objectives and the design of the project “Governance of Educational Trajectories in Europe” (GOETE and it presents some findings emerging from a case study conducted in one of the cities involved in the project, Bologna. GOETE project analyzed how educational trajectories of children and young people between the end of primary education and the beginning of post-compulsory routes are regulated in eight different EU-member states: Finland, France, Germany, Italy, Netherlands, Poland, Slovenia and the UK. The research assesses the outcomes of education, taking into account the effects of social inequalities, changes in the governance of education in terms of lifelong learning, knowledge societies and transnational educational spaces. “Life course” perspective provides an interactive understanding of educational processes and addresses the interplay between the institutionalization of individual lives and subjective biographies.

  10. Physical activity and trajectories of frailty among older adults: Evidence from the English Longitudinal Study of Ageing

    Science.gov (United States)

    Marshall, Alan; Roberts, Chrissy H.; Demakakos, Panayotes; Steptoe, Andrew; Scholes, Shaun

    2017-01-01

    Background Frail older adults are heavy users of health and social care. In order to reduce the costs associated with frailty in older age groups, safe and cost-effective strategies are required that will reduce the incidence and severity of frailty. Objective We investigated whether self-reported intensity of physical activity (sedentary, mild, moderate or vigorous) performed at least once a week can significantly reduce trajectories of frailty in older adults who are classified as non-frail at baseline (Rockwood’s Frailty Index [FI] ≤ 0.25). Methods Multi-level growth curve modelling was used to assess trajectories of frailty in 8649 non-frail adults aged 50 and over and according to baseline self-reported intensity of physical activity. Frailty was measured in five-year age cohorts based on age at baseline (50–54; 55–59; 60–64; 65–69; 70–74; 75–79; 80+) on up to 6 occasions, providing an average of 10 years of follow-up. All models were adjusted for baseline sex, education, wealth, cohabitation, smoking, and alcohol consumption. Results Compared with the sedentary reference group, mild physical activity was insufficient to significantly slow the progression of frailty, moderate physical activity reduced the progression of frailty in some age groups (particularly ages 65 and above) and vigorous activity significantly reduced the trajectory of frailty progression in all older adults. Conclusion Healthy non-frail older adults require higher intensities of physical activity for continued improvement in frailty trajectories. PMID:28152084

  11. Ten-Year Blood Pressure Trajectories, Cardiovascular Mortality, and Life Years Lost in 2 Extinction Cohorts: the Minnesota Business and Professional Men Study and the Zutphen Study

    NARCIS (Netherlands)

    Tielemans, S.M.A.J.; Geleijnse, J.M.; Menotti, A.; Boshuizen, H.C.; Soedamah-Muthu, S.S.; Jacobs, D.R.; Blackburn, H.; Kromhout, D.

    2015-01-01

    Background Blood pressure (BP) trajectories derived from measurements repeated over years have low measurement error and may improve cardiovascular disease prediction compared to single, average, and usual BP (single BP adjusted for regression dilution). We characterized 10-year BP trajectories and

  12. Early Life Factors and Inter-Country Heterogeneity in BMI Growth Trajectories of European Children: The IDEFICS Study.

    Directory of Open Access Journals (Sweden)

    Claudia Börnhorst

    Full Text Available Starting from birth, this explorative study aimed to investigate between-country differences in body mass index (BMI trajectories and whether early life factors explain these differences.The sample included 7,644 children from seven European countries (Belgium, Cyprus, Germany, Hungary, Italy, Spain, Sweden participating in the multi-centre IDEFICS study. Information on early life factors and in total 53,409 repeated measurements of height and weight from 0 to <12 years of age were collected during the baseline (2007/2008 and follow-up examination (2009/2010 supplemented by records of routine child health visits. Country-specific BMI growth curves were estimated using fractional polynomial mixed effects models. Several covariates focussing on early life factors were added to the models to investigate their role in the between-countries differences.Large between-country differences were observed with Italian children showing significantly higher mean BMI values at all ages ≥ 3 years compared to the other countries. For instance, at age 11 years mean BMI values in Italian boys and girls were 22.3 [21.9;22.8; 99% confidence interval] and 22.0 [21.5;22.4], respectively, compared to a range of 18.4 [18.1;18.8] to 20.3 [19.8;20.7] in boys and 18.2 [17.8;18.6] to 20.3 [19.8;20.7] in girls in the other countries. After adjustment for early life factors, differences between country-specific BMI curves became smaller. Maternal BMI was the factor being most strongly associated with BMI growth (p<0.01 in all countries with associations increasing during childhood. Gestational weight gain (GWG was weakly associated with BMI at birth in all countries. In some countries, positive associations between BMI growth and children not being breastfed, mothers' smoking during pregnancy and low educational level of parents were found.Early life factors seem to explain only some of the inter-country variation in growth. Maternal BMI showed the strongest association

  13. 14 CFR 417.207 - Trajectory analysis.

    Science.gov (United States)

    2010-01-01

    ... potential three-sigma trajectory dispersions about the nominal trajectory. (2) A fuel exhaustion trajectory...) Trajectory model. A final trajectory analysis must use a six-degree of freedom trajectory model to...

  14. PANTHER. Trajectory Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rintoul, Mark Daniel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Wilson, Andrew T. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Valicka, Christopher G. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Kegelmeyer, W. Philip [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Shead, Timothy M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Newton, Benjamin D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Czuchlewski, Kristina Rodriguez [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We want to organize a body of trajectories in order to identify, search for, classify and predict behavior among objects such as aircraft and ships. Existing compari- son functions such as the Fr'echet distance are computationally expensive and yield counterintuitive results in some cases. We propose an approach using feature vectors whose components represent succinctly the salient information in trajectories. These features incorporate basic information such as total distance traveled and distance be- tween start/stop points as well as geometric features related to the properties of the convex hull, trajectory curvature and general distance geometry. Additionally, these features can generally be mapped easily to behaviors of interest to humans that are searching large databases. Most of these geometric features are invariant under rigid transformation. We demonstrate the use of different subsets of these features to iden- tify trajectories similar to an exemplar, cluster a database of several hundred thousand trajectories, predict destination and apply unsupervised machine learning algorithms.

  15. Towards Efficient Search for Activity Trajectories

    DEFF Research Database (Denmark)

    Zheng, Kai; Shang, Shuo; Yuan, Jing

    2013-01-01

    The advances in location positioning and wireless communication technologies have led to a myriad of spatial trajectories representing the mobility of a variety of moving objects. While processing trajectory data with the focus of spatio-temporal features has been widely studied in the last decad...

  16. Trajectories of CBCL Attention Problems in childhood

    NARCIS (Netherlands)

    Robbers, S.C.C.; Oort, F.V.A. van; Polderman, T.J.C.; Bartels, M.; Boomsma, D.I.; Verhulst, F.C.; Huizink, A.C.

    2011-01-01

    The first aim of this study was to identify developmental trajectories of Attention Problems in twins followed from age 6 to 12 years. Second, we investigated whether singletons follow similar trajectories. Maternal longitudinal ratings on the Attention Problems (AP) subscale of the Child Behavior

  17. Trajectories of Delinquency and Parenting Styles

    Science.gov (United States)

    Hoeve, Machteld; Blokland, Arjan; Dubas, Judith Semon; Loeber, Rolf; Gerris, Jan R. M.; van der Laan, Peter H.

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering ages 10-19, we identified five distinct…

  18. Trajectories of CBCL Attention Problems in childhood

    NARCIS (Netherlands)

    S.C.C. Robbers (Sylvana); F.V.A. van Oort (Floor); T.J.C. Polderman (Tinca); M. Bartels (Meike); D.I. Boomsma (Dorret); F.C. Verhulst (Frank); G.H. Lubke (Gitta); A.C. Huizink (Anja)

    2011-01-01

    textabstractThe first aim of this study was to identify developmental trajectories of Attention Problems in twins followed from age 6 to 12 years. Second, we investigated whether singletons follow similar trajectories. Maternal longitudinal ratings on the Attention Problems (AP) subscale of the Chil

  19. Influence of size and taper of artificial canals on the trajectory of NiTi rotary instruments in cyclic fatigue studies.

    Science.gov (United States)

    Plotino, Gianluca; Grande, Nicola M; Mazza, Ciro; Petrovic, Renata; Testarelli, Luca; Gambarini, Gianluca

    2010-01-01

    The aim of this study was to investigate the influence of the shape of 3 different artificial canals on the trajectory followed by different nickel-titanium rotary instruments. Ten ProFile and Mtwo instruments, tip sizes 20 and 25, taper .06, were tested in 3 simulated root canals with an angle of curvature of 60 degrees and radius of curvature of 5 mm but with different shapes. Geometric analysis of the trajectory that each instrument followed inside the 3 different artificial canals was performed on digital images, determining 3 parameters: angle and radius of the curvature and the position of the center of the curvature. Mean values were then calculated for each instrument size in all of the artificial canals. Data were analysed using 1-way analysis of variance, Holm t test, and Student t test to determine any statistical difference (P difference was noted among the artificial canals for the radius and angle of curvature. No statistically significant difference was noted between instruments of the same size for the radius and angle of curvature and the position of the center of the curve when measured in the canal constructed on the dimension of the instruments. Different instruments follow different trajectories in artificial canals constructed with the same parameters of curvature but different shapes, depending on their different bending properties. All of the instruments respected the established parameters of curvature only when the artificial canal is designed on the dimension of the instruments. Copyright 2010 Mosby, Inc. All rights reserved.

  20. Trajectories of personal control in cancer patients receiving psychological care

    NARCIS (Netherlands)

    Zhu, Lei; Schroevers, Maya J.; van der Lee, Marije; Garssen, Bert; Stewart, Roy E.; Sanderman, Robbert; Ranchor, A.V.

    2015-01-01

    Objective This study aimed to (1) identify subgroups of cancer patients with distinct personal control trajectories during psychological care, (2) examine whether socio-demographic, clinical, and psychological care characteristics could distinguish trajectories, and (3) examine differential patterns

  1. Optimal trajectory and insertion accuracy of sacral alar iliac screws

    Directory of Open Access Journals (Sweden)

    Katsutaka Yamada

    2017-07-01

    Conclusion: The optimal trajectories of SAISs in a Japanese patient population are more lateral in males and more caudal in females. This study examines the clinical safety and accuracy of SAIS insertion on these optimal trajectories.

  2. Trajectories of personal control in cancer patients receiving psychological care

    NARCIS (Netherlands)

    Zhu, Lei; Schroevers, Maya J.; van der Lee, Marije; Garssen, Bert; Stewart, Roy E.; Sanderman, Robbert; Ranchor, Adelita V.

    2015-01-01

    Objective: This study aimed to (1) identify subgroups of cancer patients with distinct personal control trajectories during psychological care, (2) examine whether socio-demographic, clinical, and psychological care characteristics could distinguish trajectories, and (3) examine differential pattern

  3. Trajectories of personal control in cancer patients receiving psychological care

    NARCIS (Netherlands)

    Zhu, Lei; Schroevers, Maya J.; Lee, van der Marije; Garssen, Bert; Stewart, Roy E.; Sanderman, R.; Ranchor, A.V.

    2015-01-01

    Objective This study aimed to (1) identify subgroups of cancer patients with distinct personal control trajectories during psychological care, (2) examine whether socio-demographic, clinical, and psychological care characteristics could distinguish trajectories, and (3) examine differential patterns

  4. The influence of work-family conflict trajectories on self-rated health trajectories in Switzerland: a life course approach.

    Science.gov (United States)

    Cullati, Stéphane

    2014-07-01

    Self-rated health (SRH) trajectories tend to decline over a lifetime. Moreover, the Cumulative Advantage and Disadvantage (CAD) model indicates that SRH trajectories are known to consistently diverge along socioeconomic positions (SEP) over the life course. However, studies of working adults to consider the influence of work and family conflict (WFC) on SRH trajectories are scarce. We test the CAD model and hypothesise that SRH trajectories diverge over time according to socioeconomic positions and WFC trajectories accentuate this divergence. Using longitudinal data from the Swiss Household Panel (N = 2327 working respondents surveyed from 2004 to 2010), we first examine trajectories of SRH and potential divergence over time across age, gender, SEP and family status using latent growth curve analysis. Second, we assess changes in SRH trajectories in relation to changes in WFC trajectories and divergence in SRH trajectories according to gender, SEP and family status using parallel latent growth curve analysis. Three measures of WFC are used: exhaustion after work, difficulty disconnecting from work, and work interference in private family obligations. The results show that SRH trajectories slowly decline over time and that the rate of change is not influenced by age, gender or SEP, a result which does not support the CAD model. SRH trajectories are significantly correlated with exhaustion after work trajectories but not the other two WFC measures. When exhaustion after work trajectories are taken into account, SRH trajectories of higher educated people decline slower compared to less educated people, supporting the CAD hypothesis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The impact of parental educational trajectories on their adult offspring's overweight/obesity status: a study of three generations of Swedish men and women.

    Science.gov (United States)

    Chaparro, M P; Koupil, Ilona

    2014-11-01

    The objective of this study was to investigate the impact of grandparental and parental education and parental educational trajectory on their adult offspring's overweight/obesity. We used register data from the Uppsala Birth Cohort Multigenerational Study, based on a representative cohort born in Sweden 1915-1929 (G1). Our sample included 5122 women and 11,204 men who were grandchildren of G1 (G3), their parents (G2), and grandparents. G3's overweight/obesity (BMI≥25 kg/m2) was based on pre-pregnancy weight/height for women before their first birth (average age=26 years), and measured weight/height at conscription for men (average age=18 years). G1's, G2's, and G3's highest educational attainment was obtained from routine registers and classified as low, intermediate, or high based on respective sample distributions. Parental (G2) educational trajectory was defined as change in education between their own and their highest educated parent (G1), classified into 5 categories: always advantaged (AA), upward trajectory (UT), stable-intermediate (SI), downward trajectory (DT), and always disadvantaged (AD). We used hierarchical gender-stratified logistic regression models adjusted for G3's age, education, year of BMI collection, lineage and G2's year of birth and income. Grandparental and parental education were negatively associated with men's odds of overweight/obesity and parental education affected women's overweight/obesity risk. Furthermore, men and women whose parents belonged to the UT, SI, DT, and AD groups had greater odds of overweight/obesity compared to men and women whose parents belonged to the AA group (adjusted for G3's age, year of BMI collection, lineage, and G2's year of birth). These associations were attenuated when further adjusting for parental income and G3's own education. Socioeconomic inequalities can have long-term consequences and impact the health of future generations. For overweight/obesity in concurrent young cohorts, this inequality

  6. Modeling of quantum-information processing with Ehrenfest guided trajectories: A case study with spin-boson-like couplings

    Science.gov (United States)

    Ye, Sai-Yun; Shalashilin, Dmitrii; Serafini, Alessio

    2012-09-01

    We apply a numerical method based on multiconfigurational Ehrenfest trajectories and demonstrate converged results for the Choi fidelity of an entangling quantum gate between two two-level systems interacting through a set of bosonic modes. We consider both spin-boson and rotating-wave Hamiltonians for various numbers of mediating modes (from 1 to 100) and extend our treatment to include finite temperatures. Our results apply to two-level impurities interacting with the same band of a photonic crystal or to two distant ions interacting with the same set of motional degrees of freedom.

  7. Trajectories of Intimate Partner Violence Victimization

    Directory of Open Access Journals (Sweden)

    Kevin M. Swartout

    2012-08-01

    Full Text Available Introduction: The purposes of this study were to assess the extent to which latent trajectories of female intimate partner violence (IPV victimization exist; and, if so, use negative childhood experiences to predict trajectory membership.Methods: We collected data from 1,575 women at 5 time-points regarding experiences during adolescence and their 4 years of college. We used latent class growth analysis to fit a series of personcentered, longitudinal models ranging from 1 to 5 trajectories. Once the best-fitting model was selected, we used negative childhood experience variables—sexual abuse, physical abuse, and witnessing domestic violence—to predict most-likely trajectory membership via multinomial logistic regression.Results: A 5-trajectory model best fit the data both statistically and in terms of interpretability. The trajectories across time were interpreted as low or no IPV, low to moderate IPV, moderate to low IPV, high to moderate IPV, and high and increasing IPV, respectively. Negative childhood experiences differentiated trajectory membership, somewhat, with childhood sexual abuse as a consistent predictor of membership in elevated IPV trajectories.Conclusion: Our analyses show how IPV risk changes over time and in different ways. These differential patterns of IPV suggest the need for prevention strategies tailored for women that consider victimization experiences in childhood and early adulthood. [West J Emerg Med. 2012;13(3:272–277.

  8. Efficient Spatial Keyword Search in Trajectory Databases

    CERN Document Server

    Cong, Gao; Ooi, Beng Chin; Zhang, Dongxiang; Zhang, Meihui

    2012-01-01

    An increasing amount of trajectory data is being annotated with text descriptions to better capture the semantics associated with locations. The fusion of spatial locations and text descriptions in trajectories engenders a new type of top-$k$ queries that take into account both aspects. Each trajectory in consideration consists of a sequence of geo-spatial locations associated with text descriptions. Given a user location $\\lambda$ and a keyword set $\\psi$, a top-$k$ query returns $k$ trajectories whose text descriptions cover the keywords $\\psi$ and that have the shortest match distance. To the best of our knowledge, previous research on querying trajectory databases has focused on trajectory data without any text description, and no existing work has studied such kind of top-$k$ queries on trajectories. This paper proposes one novel method for efficiently computing top-$k$ trajectories. The method is developed based on a new hybrid index, cell-keyword conscious B$^+$-tree, denoted by \\cellbtree, which enabl...

  9. Quantum dynamics study of energy requirement on reactivity for the HBr + OH reaction with a negative-energy barrier

    Science.gov (United States)

    Wang, Yuping; Li, Yida; Wang, Dunyou

    2017-01-01

    A time-dependent, quantum reaction dynamics approach in full dimensional, six degrees of freedom was carried out to study the energy requirement on reactivity for the HBr + OH reaction with an early, negative energy barrier. The calculation shows both the HBr and OH vibrational excitations enhance the reactivity. However, even this reaction has a negative energy barrier, the calculation shows not all forms of energy are equally effective in promoting the reactivity. On the basis of equal amount of total energy, the vibrational energies of both the HBr and OH are more effective in enhancing the reactivity than the translational energy, whereas the rotational excitations of both the HBr and OH hinder the reactivity. The rate constants were also calculated for the temperature range between 5 to 500 K. The quantal rate constants have a better slope agreement with the experimental data than quasi-classical trajectory results.

  10. Theoretical Study of Isotopic Effect of Oxygen Atom on the Stereodynamics for the O(3P)+D2→ OD+D Reaction

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-Li; SHI Ying

    2010-01-01

    @@ Quasi-classical trajectory theory is used to study the isotope effect of oxygen atoms on the vector correlations in the O(3p)+D2 reaction at a collision energy of 25kcal/mol using accurate potential energy surface of the 3 A' triplet state.The distributions of p(θr)and the distribution of dihedral angel p(ψr)as well as p(θr,ψr)are calculated.Moreover,four polarization-dependent generalized differential cross sections(PDDCSs)of product are presented in the center-of-mass frame.The results indicate that the polarization of the product presents different characters for the isotope effect of oxygen atoms.Isotopic substitute can cause obviously different effects on the four PDDCSs.

  11. Trajectory Browser: An Online Tool for Interplanetary Trajectory Analysis and Visualization

    Science.gov (United States)

    Foster, Cyrus James

    2013-01-01

    The trajectory browser is a web-based tool developed at the NASA Ames Research Center for finding preliminary trajectories to planetary bodies and for providing relevant launch date, time-of-flight and (Delta)V requirements. The site hosts a database of transfer trajectories from Earth to planets and small-bodies for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and (Delta)V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies.

  12. Ornithopter transition trajectories

    Science.gov (United States)

    Dietl, John M.; Garcia, Ephrahim

    2010-04-01

    The design of stable trim conditions for forward flight and for hover has been achieved. In forward flight, an ornithopter is configured like a conventional airplane or large bird. Its fuselage is essentially horizontal and the wings heave in a vertical plane. In hover, however, the body pitches vertically so that the wing stroke in the horizontal plane. Thrust directed downward, the vehicle remains aloft while the downdraft envelops the tail to provide enough flow for vehicle control and stabilization. To connect these trajectories dynamically is the goal. The naïve approach-to choose two stable trajectories and switch between them-has been accomplished. A new approach is to establish an open-loop trajectory through a trajectory optimization algorithm-optimized for shortest altitude drop, shortest stopping distance, or lowest energy consumption.

  13. Personalized trajectory matching in spatial networks

    KAUST Repository

    Shang, Shuo

    2013-07-31

    With the increasing availability of moving-object tracking data, trajectory search and matching is increasingly important. We propose and investigate a novel problem called personalized trajectory matching (PTM). In contrast to conventional trajectory similarity search by spatial distance only, PTM takes into account the significance of each sample point in a query trajectory. A PTM query takes a trajectory with user-specified weights for each sample point in the trajectory as its argument. It returns the trajectory in an argument data set with the highest similarity to the query trajectory. We believe that this type of query may bring significant benefits to users in many popular applications such as route planning, carpooling, friend recommendation, traffic analysis, urban computing, and location-based services in general. PTM query processing faces two challenges: how to prune the search space during the query processing and how to schedule multiple so-called expansion centers effectively. To address these challenges, a novel two-phase search algorithm is proposed that carefully selects a set of expansion centers from the query trajectory and exploits upper and lower bounds to prune the search space in the spatial and temporal domains. An efficiency study reveals that the algorithm explores the minimum search space in both domains. Second, a heuristic search strategy based on priority ranking is developed to schedule the multiple expansion centers, which can further prune the search space and enhance the query efficiency. The performance of the PTM query is studied in extensive experiments based on real and synthetic trajectory data sets. © 2013 Springer-Verlag Berlin Heidelberg.

  14. Automated Cooperative Trajectories

    Science.gov (United States)

    Hanson, Curt; Pahle, Joseph; Brown, Nelson

    2015-01-01

    This presentation is an overview of the Automated Cooperative Trajectories project. An introduction to the phenomena of wake vortices is given, along with a summary of past research into the possibility of extracting energy from the wake by flying close parallel trajectories. Challenges and barriers to adoption of civilian automatic wake surfing technology are identified. A hardware-in-the-loop simulation is described that will support future research. Finally, a roadmap for future research and technology transition is proposed.

  15. Developmental trajectory from early responses to transgressions to future antisocial behavior: evidence for the role of the parent-child relationship from two longitudinal studies.

    Science.gov (United States)

    Kim, Sanghag; Kochanska, Grazyna; Boldt, Lea J; Nordling, Jamie Koenig; O'Bleness, Jessica J

    2014-02-01

    Parent-child relationships are critical in development, but much remains to be learned about the mechanisms of their impact. We examined the early parent-child relationship as a moderator of the developmental trajectory from children's affective and behavioral responses to transgressions to future antisocial, externalizing behavior problems in the Family Study (102 community mothers, fathers, and infants, followed through age 8) and the Play Study (186 low-income, diverse mothers and toddlers, followed for 10 months). The relationship quality was indexed by attachment security in the Family Study and maternal responsiveness in the Play Study. Responses to transgressions (tense discomfort and reparation) were observed in laboratory mishaps wherein children believed they had damaged a valued object. Antisocial outcomes were rated by parents. In both studies, early relationships moderated the future developmental trajectory: diminished tense discomfort predicted more antisocial outcomes, but only in insecure or unresponsive relationships. That risk was defused in secure or responsive relationships. Moderated mediation analyses in the Family Study indicated that the links between diminished tense discomfort and future antisocial behavior in insecure parent-child dyads were mediated by stronger discipline pressure from parents. By indirectly influencing future developmental sequelae, early relationships may increase or decrease the probability that the parent-child dyad will embark on a path toward antisocial outcomes.

  16. Developmental Trajectories of Childhood Obesity and Risk Behaviors in Adolescence

    Science.gov (United States)

    Huang, David Y. C.; Lanza, H. Isabella; Wright-Volel, Kynna; Anglin, M. Douglas

    2013-01-01

    Using group-based trajectory modeling, this study examined 5156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth to identify developmental trajectories of obesity from ages 6-18 and evaluate associations of such trajectories with risk behaviors and psychosocial health in adolescence. Four distinctive obesity…

  17. Developmental Trajectories of Childhood Obesity and Risk Behaviors in Adolescence

    Science.gov (United States)

    Huang, David Y. C.; Lanza, H. Isabella; Wright-Volel, Kynna; Anglin, M. Douglas

    2013-01-01

    Using group-based trajectory modeling, this study examined 5156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth to identify developmental trajectories of obesity from ages 6-18 and evaluate associations of such trajectories with risk behaviors and psychosocial health in adolescence. Four distinctive obesity…

  18. Saguenay Youth Study: A multi-generational approach to studying virtual trajectories of the brain and cardio-metabolic health

    Directory of Open Access Journals (Sweden)

    T. Paus

    2015-02-01

    Full Text Available This paper provides an overview of the Saguenay Youth Study (SYS and its parental arm. The overarching goal of this effort is to develop trans-generational models of developmental cascades contributing to the emergence of common chronic disorders, such as depression, addictions, dementia and cardio-metabolic diseases. Over the past 10 years, we have acquired detailed brain and cardio-metabolic phenotypes, and genome-wide genotypes, in 1029 adolescents recruited in a population with a known genetic founder effect. At present, we are extending this dataset to acquire comparable phenotypes and genotypes in the biological parents of these individuals. After providing conceptual background for this work (transactions across time, systems and organs, we describe briefly the tools employed in the adolescent arm of this cohort and highlight some of the initial accomplishments. We then outline in detail the phenotyping protocol used to acquire comparable data in the parents.

  19. Developmental Trajectory of Audiovisual Speech Integration in Early Infancy. A Review of Studies Using the McGurk Paradigm

    Directory of Open Access Journals (Sweden)

    Tomalski Przemysław

    2015-10-01

    Full Text Available Apart from their remarkable phonological skills young infants prior to their first birthday show ability to match the mouth articulation they see with the speech sounds they hear. They are able to detect the audiovisual conflict of speech and to selectively attend to articulating mouth depending on audiovisual congruency. Early audiovisual speech processing is an important aspect of language development, related not only to phonological knowledge, but also to language production during subsequent years. Th is article reviews recent experimental work delineating the complex developmental trajectory of audiovisual mismatch detection. Th e central issue is the role of age-related changes in visual scanning of audiovisual speech and the corresponding changes in neural signatures of audiovisual speech processing in the second half of the first year of life. Th is phenomenon is discussed in the context of recent theories of perceptual development and existing data on the neural organisation of the infant ‘social brain’.

  20. An experimental study of visual flight trajectory tracking and pose prediction for the automatic computer control of a miniature airship

    Science.gov (United States)

    Haecker, Jens; Kroeplin, Bernd H.

    2003-08-01

    This paper describes our current work in developing a vision-based tracking and trajectory prediction system for an aerial robot based on low-cost digital cameras, image processing techniques, and a filtering and prediction algorithm. The system determines the pose (location and orientation) of a miniature airship, online during indoor flight, and will be used in a development framework for a future autonomous flight control system. Object localization is achieved by tracking an infra-red target array mounted to a model airship. Its pose in three-dimensional space can be computed from corresponding points in the images of two cameras which are calibrated in a global coordinate system. The calibration procedure and the localization, as well as some aspects of the measurement accuracy achieved, are discussed. Real-world applications provide an uncertain static or dynamic environment which complicates the tracking of a target. To overcome problems due to noisy data or even failed target detection in image frames, a filtering procedure is applied for estimating the airship's pose. In a first step, points in the two-dimensional image planes are directly tracked and propagated forward to the vehicle pose. In a second step, an adaptive noise Kalman filter is applied for estimating and predicting the flight trajectory. Its state is propagated back to points in the image planes to guide the detection algorithm by defining regions of confidence. Both approaches are combined in a tracking algorithm. In-flight measurements are used to validate the parameters of the adaption procedure. Some experimental results are shown.

  1. Childhood body mass index trajectories: modeling, characterizing, pairwise correlations and socio-demographic predictors of trajectory characteristics

    OpenAIRE

    Wen Xiaozhong; Kleinman Ken; Gillman Matthew W; Rifas-Shiman Sheryl L; Taveras Elsie M

    2012-01-01

    Abstract Background Modeling childhood body mass index (BMI) trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information. Methods Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with f...

  2. Quasi-classical expansion of the star-triangle relation and integrable systems on quad-graphs

    Science.gov (United States)

    Bazhanov, Vladimir V.; Kels, Andrew P.; Sergeev, Sergey M.

    2016-11-01

    In this paper we give an overview of exactly solved edge-interaction models, where the spins are placed on sites of a planar lattice and interact through edges connecting the sites. We only consider the case of a single spin degree of freedom at each site of the lattice. The Yang-Baxter equation for such models takes a particular simple form called the star-triangle relation. Interestigly all known solutions of this relation can be obtained as particular cases of a single ‘master solution’, which is expressed through the elliptic gamma function and have continuous spins taking values on the circle. We show that in the low-temperature (or quasi-classical) limit these lattice models reproduce classical discrete integrable systems on planar graphs previously obtained and classified by Adler, Bobenko and Suris through the consistency-around-a-cube approach. We also discuss inversion relations, the physicical meaning of Baxter’s rapidity-independent parameter in the star-triangle relations and the invariance of the action of the classical systems under the star-triangle (or cube-flip) transformation of the lattice, which is a direct consequence of Baxter’s Z-invariance in the associated lattice models. Dedicated to Professor Rodney Baxter on the occasion of his 75th birthday.

  3. Moon Landing Trajectory Optimization

    Directory of Open Access Journals (Sweden)

    Ibrahim Mustafa MEHEDI

    2016-03-01

    Full Text Available Trajectory optimization is a crucial process during the planning phase of a spacecraft landing mission. Once a trajectory is determined, guidance algorithms are created to guide the vehicle along the given trajectory. Because fuel mass is a major driver of the total vehicle mass, and thus mission cost, the objective of most guidance algorithms is to minimize the required fuel consumption. Most of the existing algorithms are termed as “near-optimal” regarding fuel expenditure. The question arises as to how close to optimal are these guidance algorithms. To answer this question, numerical trajectory optimization techniques are often required. With the emergence of improved processing power and the application of new methods, more direct approaches may be employed to achieve high accuracy without the associated difficulties in computation or pre-existing knowledge of the solution. An example of such an approach is DIDO optimization. This technique is applied in the current research to find these minimum fuel optimal trajectories.

  4. [Oxaliplatin -- A 10-Year Trajectory].

    Science.gov (United States)

    Kanaji, Shingo; Oki, Eiji; Saeki, Hiroshi; Kitao, Hiroyuki; Maehara, Yoshihiko; Kakeji, Yoshihiro

    2016-06-01

    Oxaliplatin(Elplat(®)iv infusion solution)is a third-generation 1,2-DACH-platinum derivative. A number of international clinical trials have investigated the effects of this drug for each of its four indications. Building on the results of these earlier studies, much research has also been carried out in Japan in terms of developing and accumulating evidence on oxaliplatin. This report reviews the trajectory of its use over the last 10-years and considers its future potential.

  5. Periodic billiard trajectories in polyhedra

    CERN Document Server

    Bedaride, Nicolas

    2011-01-01

    We consider the billiard map inside a polyhedron. We give a condition for the stability of the periodic trajectories. We apply this result to the case of the tetrahedron. We deduce the existence of an open set of tetrahedra which have a periodic orbit of length four (generalization of Fagnano's orbit for triangles), moreover we can study completly the orbit of points along this coding.

  6. Evaluating Trajectory Queries over Imprecise Location Data

    DEFF Research Database (Denmark)

    Xie, Scott, Xike; Cheng, Reynold; Yiu, Man Lung

    2012-01-01

    Trajectory queries, which retrieve nearby objects for every point of a given route, can be used to identify alerts of potential threats along a vessel route, or monitor the adjacent rescuers to a travel path. However, the locations of these objects (e.g., threats, succours) may not be precisely......, the query is quite time-consuming, since all the points on the trajectory are considered. In this paper, we study how to efficiently evaluate trajectory queries over imprecise location data, by proposing a new concept called the u-bisector. In general, the u-bisector is an extension of bisector to handle...

  7. Age trajectories of stroke case fatality

    DEFF Research Database (Denmark)

    Olsen, Tom Skyhøj; Andersen, Zorana Jovanovic; Andersen, Klaus Kaae

    2011-01-01

    Mortality rates level off at older ages. Age trajectories of stroke case-fatality rates were studied with the aim of investigating prevalence of this phenomenon, specifically in case-fatality rates at older ages.......Mortality rates level off at older ages. Age trajectories of stroke case-fatality rates were studied with the aim of investigating prevalence of this phenomenon, specifically in case-fatality rates at older ages....

  8. Geometric diffusion of quantum trajectories.

    Science.gov (United States)

    Yang, Fan; Liu, Ren-Bao

    2015-07-16

    A quantum object can acquire a geometric phase (such as Berry phases and Aharonov-Bohm phases) when evolving along a path in a parameter space with non-trivial gauge structures. Inherent to quantum evolutions of wavepackets, quantum diffusion occurs along quantum trajectories. Here we show that quantum diffusion can also be geometric as characterized by the imaginary part of a geometric phase. The geometric quantum diffusion results from interference between different instantaneous eigenstate pathways which have different geometric phases during the adiabatic evolution. As a specific example, we study the quantum trajectories of optically excited electron-hole pairs in time-reversal symmetric insulators, driven by an elliptically polarized terahertz field. The imaginary geometric phase manifests itself as elliptical polarization in the terahertz sideband generation. The geometric quantum diffusion adds a new dimension to geometric phases and may have applications in many fields of physics, e.g., transport in topological insulators and novel electro-optical effects.

  9. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Curci, G.

    2014-11-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyse aerosol optical depth τa(z) values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean τa(3.5 km) ∼ 0.04 - and shows a seasonal trend with a winter minimum - τa(3.5 km) ∼ 0.03 -, and a summer maximum - τa(3.5 km) ∼ 0.06 -, and an unexpected increase from August to September - τa(3.5 km) ∼ 0.055. We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from the Pacific Ocean. Average concentrations are affected by continental sources (wind-blown dust and urban pollution), whilst the peak observed in September and October could be linked to biomass burning in the northern part of Argentina or air pollution coming from surrounding urban areas.

  10. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    CERN Document Server

    Curci, Gabriele

    2014-01-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyze aerosol optical depth $\\tau_{\\rm a}(z)$ values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of the Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.04$ - and shows a seasonal trend with a winter minimum - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.03$ -, and a summer maximum - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.06$ -, and an unexpected increase from August to September - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.055$). We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from t...

  11. Social functioning trajectories of young first-episode psychosis patients with and without cannabis misuse: a 30-month follow-up study.

    Science.gov (United States)

    González-Blanch, César; Gleeson, John F; Koval, Peter; Cotton, Sue M; McGorry, Patrick D; Alvarez-Jimenez, Mario

    2015-01-01

    The aim of the study was to investigate trajectories of social functioning in young people with first-episode psychosis (FEP) with and without cannabis misuse using a secondary analysis of data from the Episode-II trial. Forty-two young people with FEP and comorbid cannabis use disorder were compared with 39 young people with FEP but without a cannabis use disorder. Social functioning was assessed every 6 months during a 30-month follow-up. Multilevel linear growth curve modeling was used to compare the social functioning trajectories over time for those with and without cannabis misuse. Cannabis misuse was not associated with social functioning at baseline assessment. Over a 30-month follow-up, FEP patients without cannabis disorder showed significant improvements in their social functioning, whereas patients with cannabis misuse at baseline displayed no such improvement. Patients with and without cannabis misuse differed significantly in their levels of social functioning after 24 months. Similar results were obtained after adjusting for potential confounders (i.e., age, gender, negative symptoms, premorbid functioning, DSM-IV diagnoses, baseline social functioning and other substance use). In the context of a specialized early intervention service, patients with cannabis misuse at baseline did not attain the improvements in social outcomes observed in their counterparts without cannabis misuse. There is a need to develop effective interventions to reduce cannabis misuse to ultimately improve social outcomes in young people with psychosis.

  12. A Big Five approach to self-regulation: personality traits and health trajectories in the Hawaii longitudinal study of personality and health.

    Science.gov (United States)

    Hampson, Sarah E; Edmonds, Grant W; Barckley, Maureen; Goldberg, Lewis R; Dubanoski, Joan P; Hillier, Teresa A

    2016-01-01

    Self-regulatory processes influencing health outcomes may have their origins in childhood personality traits. The Big Five approach to personality was used here to investigate the associations between childhood traits, trait-related regulatory processes and changes in health across middle age. Participants (N = 1176) were members of the Hawaii longitudinal study of personality and health. Teacher assessments of the participants' traits when they were in elementary school were related to trajectories of self-rated health measured on 6 occasions over 14 years in middle age. Five trajectories of self-rated health were identified by latent class growth analysis: Stable Excellent, Stable Very Good, Good, Decreasing and Poor. Childhood Conscientiousness was the only childhood trait to predict membership in the Decreasing class vs. the combined healthy classes (Stable Excellent, Stable Very Good and Good), even after controlling for adult Conscientiousness and the other adult Big Five traits. The Decreasing class had poorer objectively assessed clinical health measured on one occasion in middle age, was less well-educated, and had a history of more lifespan health-damaging behaviors compared to the combined healthy classes. These findings suggest that higher levels of childhood Conscientiousness (i.e. greater self-discipline and goal-directedness) may prevent subsequent health decline decades later through self-regulatory processes involving the acquisition of lifelong healthful behavior patterns and higher educational attainment.

  13. Social functioning trajectories of young first-episode psychosis patients with and without cannabis misuse: a 30-month follow-up study.

    Directory of Open Access Journals (Sweden)

    César González-Blanch

    Full Text Available The aim of the study was to investigate trajectories of social functioning in young people with first-episode psychosis (FEP with and without cannabis misuse using a secondary analysis of data from the Episode-II trial. Forty-two young people with FEP and comorbid cannabis use disorder were compared with 39 young people with FEP but without a cannabis use disorder. Social functioning was assessed every 6 months during a 30-month follow-up. Multilevel linear growth curve modeling was used to compare the social functioning trajectories over time for those with and without cannabis misuse. Cannabis misuse was not associated with social functioning at baseline assessment. Over a 30-month follow-up, FEP patients without cannabis disorder showed significant improvements in their social functioning, whereas patients with cannabis misuse at baseline displayed no such improvement. Patients with and without cannabis misuse differed significantly in their levels of social functioning after 24 months. Similar results were obtained after adjusting for potential confounders (i.e., age, gender, negative symptoms, premorbid functioning, DSM-IV diagnoses, baseline social functioning and other substance use. In the context of a specialized early intervention service, patients with cannabis misuse at baseline did not attain the improvements in social outcomes observed in their counterparts without cannabis misuse. There is a need to develop effective interventions to reduce cannabis misuse to ultimately improve social outcomes in young people with psychosis.

  14. Is the war really over? A 20-year longitudinal study on trajectories of suicidal ideation and posttraumatic stress symptoms following combat.

    Science.gov (United States)

    Snir, Avigal; Levi-Belz, Yossi; Solomon, Zahava

    2017-01-01

    Combat stress reaction (CSR) has widespread long-term consequences, including profound psychopathology in the form of posttraumatic stress disorder (PTSD). Studies have established the link between combat, PTSD, and suicidality. However, little is known about the temporal course of suicidal ideation (SI) in general, specifically among war veterans. We aimed to trace the trajectories of SI in the aftermath of war and to explore the role of CSR and PTSD in SI trajectories. Israeli veterans with CSR (n=164) and a matched control group (NCSR, n=111) were assessed, using self-report measures at three points over the course of 20 years. Veterans with CSR reported significantly higher levels of SI, compared to the NCSR group at all measurement points. Among veterans with CSR, SI increased 2 years after the war and then decreased 20 years following the war. This pattern was particularly characteristic of veterans with chronic PTSD. The results indicate that CSR is a strong predictor of subsequent PTSD and suicidality. These findings highlight the importance of prevention and treatment efforts for these traumatized veterans, who are at risk for suicide even 20 years after the end of the war.

  15. Kinematic evaluation of virtual walking trajectories.

    Science.gov (United States)

    Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

    2013-04-01

    Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

  16. Reduced parameter model on trajectory tracking data with applications

    Institute of Scientific and Technical Information of China (English)

    王正明; 朱炬波

    1999-01-01

    The data fusion in tracking the same trajectory by multi-measurernent unit (MMU) is considered. Firstly, the reduced parameter model (RPM) of trajectory parameter (TP), system error and random error are presented,and then the RPM on trajectory tracking data (TTD) is obtained, a weighted method on measuring elements (ME) is studied and criteria on selection of ME based on residual and accuracy estimation are put forward. According to RPM,the problem about selection of ME and self-calibration of TTD is thoroughly investigated. The method improves data accuracy in trajectory tracking obviously and gives accuracy evaluation of trajectory tracking system simultaneously.

  17. Trajectory Based Traffic Analysis

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2013-01-01

    -and-click analysis, due to a novel and efficient indexing structure. With the web-site daisy.aau.dk/its/spqdemo/we will demonstrate several analyses, using a very large real-world data set consisting of 1.9 billion GPS records (1.5 million trajectories) recorded from more than 13000 vehicles, and touching most...

  18. Trajectory options for the DART mission

    Science.gov (United States)

    Atchison, Justin A.; Ozimek, Martin T.; Kantsiper, Brian L.; Cheng, Andrew F.

    2016-06-01

    This study presents interplanetary trajectory options for the Double Asteroid Redirection Test (DART) spacecraft to reach the near Earth object, Didymos binary system, during its 2022 Earth conjunction. DART represents a component of a joint NASA-ESA mission to study near Earth object kinetic impact deflection. The DART trajectory must satisfy mission objectives for arrival timing, geometry, and lighting while minimizing launch vehicle and spacecraft propellant requirements. Chemical propulsion trajectories are feasible from two candidate launch windows in late 2020 and 2021. The 2020 trajectories are highly perturbed by Earth's orbit, requiring post-launch deep space maneuvers to retarget the Didymos system. Within these windows, opportunities exist for flybys of additional near Earth objects: Orpheus in 2021 or 2007 YJ in 2022. A second impact attempt, in the event that the first impact is unsuccessful, can be added at the expense of a shorter launch window and increased (∼3x) spacecraft ΔV . However, the second impact arrival geometry has poor lighting, high Earth ranges, and would require additional degrees of freedom for solar panel and/or antenna gimbals. A low-thrust spacecraft configuration increases the trajectory flexibility. A solar electric propulsion spacecraft could be affordably launched as a secondary spacecraft in an Earth orbit and spiral out to target the requisite interplanetary departure condition. A sample solar electric trajectory was constructed from an Earth geostationary transfer using a representative 1.5 kW thruster. The trajectory requires 9 months to depart Earth's sphere of influence, after which its interplanetary trajectory includes a flyby of Orpheus and a second Didymos impact attempt. The solar electric spacecraft implementation would impose additional bus design constraints, including large solar arrays that could pose challenges for terminal guidance. On the basis of this study, there are many feasible options for DART to

  19. Mitochondrial uncoupling as a regulator of life-history trajectories in birds: an experimental study in the zebra finch.

    Science.gov (United States)

    Stier, Antoine; Bize, Pierre; Roussel, Damien; Schull, Quentin; Massemin, Sylvie; Criscuolo, François

    2014-10-01

    Mitochondria have a fundamental role in the transduction of energy from food into ATP. The coupling between food oxidation and ATP production is never perfect, but may nevertheless be of evolutionary significance. The 'uncoupling to survive' hypothesis suggests that 'mild' mitochondrial uncoupling evolved as a protective mechanism against the excessive production of damaging reactive oxygen species (ROS). Because resource allocation and ROS production are thought to shape animal life histories, alternative life-history trajectories might be driven by individual variation in the degree of mitochondrial uncoupling. We tested this hypothesis in a small bird species, the zebra finch (Taeniopygia guttata), by treating adults with the artificial mitochondrial uncoupler 2,4-dinitrophenol (DNP) over a 32-month period. In agreement with our expectations, the uncoupling treatment increased metabolic rate. However, we found no evidence that treated birds enjoyed lower oxidative stress levels or greater survival rates, in contrast to previous results in other taxa. In vitro experiments revealed lower sensitivity of ROS production to DNP in mitochondria isolated from skeletal muscles of zebra finch than mouse. In addition, we found significant reductions in the number of eggs laid and in the inflammatory immune response in treated birds. Altogether, our data suggest that the 'uncoupling to survive' hypothesis may not be applicable for zebra finches, presumably because of lower effects of mitochondrial uncoupling on mitochondrial ROS production in birds than in mammals. Nevertheless, mitochondrial uncoupling appeared to be a potential life-history regulator of traits such as fecundity and immunity at adulthood, even with food supplied ad libitum. © 2014. Published by The Company of Biologists Ltd.

  20. Clustering vessel trajectories with alignment kernels under trajectory compression

    NARCIS (Netherlands)

    de Vries, G.; van Someren, M.

    2010-01-01

    In this paper we apply a selection of alignment measures, such as dynamic time warping and edit distance, to the problem of clustering vessel trajectories. Vessel trajectories are an example of moving object trajectories, which have recently become an important research topic. The alignment measures

  1. Generalized London theory of the mixed state of high-{kappa} superconductors as a projection of the quasiclassical Eilenberger approach

    Energy Technology Data Exchange (ETDEWEB)

    Belova, P., E-mail: Polina.Belova@lut.fi [Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland); Petrozavodsk State University, Lenin Str. 33, RU-185640 Petrozavodsk (Russian Federation); Zakharchuk, I. [Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland); Saint-Petersburg Electrotechnical University, Popov Str. 5, RU-197376 St. Petersburg (Russian Federation); Safonchik, M. [Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland); A.F. Ioffe Physico-Technical Institute, St. Petersburg 194021 (Russian Federation); Traito, K.B.; Laehderanta, E. [Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland)

    2012-06-15

    The generalized London equation in the mixed state of high-{kappa} s-wave pairing superconductors with impurities is considered as a projection of the quasiclassical nonlocal nonlinear Eilenberger theory. Only one fitting parameter - the cutoff parameter {xi}{sub h} - is used in the theory. The distribution of the magnetic field is calculated self-consistently. Both nonlocal effects originated from extended states between the vortices and bound Andreev states in the vortex are taken into account. Comparison with different analytical nonlocal linear approaches (the Kogan-Gurevich, Amin-Franz-Affleck, Kogan-Zhelezina models) including only extended states is done. The importance of the Kramer-Pesch nonlinear effect and the field dependence of the cutoff parameter is emphasized and their strong influence on the variance of the magnetic field is found. The influence of the impurities on the ratio of the cutoff parameter {xi}{sub h} and the Ginzburg-Landau coherence length {xi}{sub c2} is considered. Quasiparticle scattering by impurities and lowering of the temperature reduces the value of {xi}{sub h} to the values much less than {xi}{sub c2}. This is different from the prediction of the local Ginzburg-Landau theory where {xi}{sub h} is scaled by {xi}{sub c2}. It is found that impurities influence by different way on the cutoff parameter {xi}{sub h} and the order parameter coherence length {xi}{sub 1}. The {xi}{sub h} decreases monotonously with the impurity scattering time in contrast to the nonmonotonous behavior of {xi}{sub 1}. The results can be used for analysis of the {mu}SR experimental data.

  2. Study on Conception of Service Innovation Trajectory: A Comment on Theory of Technological Trajectory%服务创新轨道概念初探:兼评技术轨道的适用性

    Institute of Scientific and Technical Information of China (English)

    吴贵生; 蔺雷

    2012-01-01

    基于对技术轨道理论的评述,从服务自身的特性出发,对服务创新轨道的概念进行归纳分析,阐释服务创新轨道的内涵、特性,比较服务创新轨道与技术创新轨道的异同。结果显示:第一,解决因服务特性而产生的问题,是形成服务创新轨道的根本基础,这内在规定了服务创新活动的方向和路径;第二,市场、科技和制度环境等外部规定性要素,以及企业的战略和知识基础等,也对服务创新轨道的形成产生重要影响;第三,服务创新轨道的概念更为宽泛,与具有严格内在技术规定性的制造业技术轨道相比,服务创新轨道具有多样性、非排斥性、弱连续性等特性;第四,技术轨道理论只在一定程度上适用于服务创新,技术轨道是服务创新的一种可选轨道。%This paper studies the concept of service innovation trajectory based on the discussion of technological trajectory theory and the anal ysis on the features of service activities. Four main findings are listed. The first is that,innovation trajectory in services is a type of problem-sol; ving trajectory whieh originated from the traits of services activities. The second is that,in addition to service traits, external faetors such as market,institution and science ~ technology,and firm factors such as strategy and knowledge base, would also influence innovation trajectory in services. The third is that, relative to technological trajectory, service innovation trajectory shows some specific characteristics such as weak ac~ cumulation,non-exclusion of other trajectories and diversity. The last is that,technological trajectory is applicable to service innovation activities to a certain degree. It tries to contribute to the catching-up process of services in latecomers and also contribute to the development of innovation trajectory theory.

  3. Developmental trajectories of fronto-executive functions in 22q11.2 deletion syndrome: A preliminary study

    LENUS (Irish Health Repository)

    Howley, S A

    2011-01-01

    22qll.2 deletion syndrome (22qllDS) is associated with borderline-mild intellectual disability and specific neurocognitive deficits, particularly in prefrontally-mediated executive functions (EF). There is evidence for white matter abnormalities in frontal cortical regions in 22qllDS, however little is known about the development of EF across the age range. Forty-eight individuals with 22qllDS were divided into 3 age groups: Child (7 male; n = 16; 6–11 years; M (SD) age = 8.4 (1.7); mean FSIQ = 72.9); Adolescent (7 male; n = 15; 12–15 years; M (SD) age = 13.1 (0.8); mean FSIQ = 68.0) and Adult (7 male; n = 17; 16–45 years; M (SD) age = 28.8 (11.5); mean FSIQ = 69.6). Forty healthy controls were also recruited and divided into the same 3 age groups: Child (6 male; 6–11 years, n = 12; M (SD) age = 9.3 (1.7); mean FSIQ = 99.1); Adolescent (6 male; 12–15 years; n = 12; M (SD) age = 13.2 (1.1); mean FSIQ = 100.9) and Adult (6 male; 16–45 years; n = 16; M (SD) age = 28.8 (9.4); mean FSIQ = 109). All participants completed standardised tests of a range of executive functions, specifically working memory, planning, problem-solving, strategy formation, cognitive flexibility and inhibition, and cross-sectional developmental trajectories of each function were constructed. No age-mediated improvements on EF tasks were observed in the 22qllDS groups, with the exception of verbal working memory. The control group exhibited significant age-mediated improvements in working memory, strategy formation and planning efficiency. These findings support the hypothesis that 22qllDS individuals experience atypical development of neuroanatomical regions and networks associated with EF in typical individuals. Future longitudinal work is required to examine intra-individual development of executive and non-executive cognitive processes.

  4. Analysis of Controlled Trajectory Optimization for Canard Trajectory Correction Fuze

    Institute of Scientific and Technical Information of China (English)

    郭泽荣; 李世义; 申强

    2004-01-01

    The optimization method of the canard trajectory correction fuze's controlled trajectory phase is researched by using the aerodynamics of aerocraft and the optimal control theory, the trajectory parameters of the controlled trajectory phase based on the least energy cost are determined. On the basis of determining the control starting point and the target point, the optimal trajectory and the variation rule of the normal overload with the least energy cost are provided, when there is no time restriction in the simulation process. The results provide a theoretical basis for the structure design of the canard mechanism.

  5. Semantic enrichment of GPS trajectories

    NARCIS (Netherlands)

    Graaff, de Victor; Keulen, van Maurice; By, de Rolf

    2012-01-01

    Semantic annotation of GPS trajectories helps us to recognize the interests of the creator of the GPS trajectories. Automating this trajectory annotation circumvents the requirement of additional user input. To annotate the GPS traces automatically, two types of automated input are required: 1) a co

  6. A demonstration and evaluation of trajectory mapping

    Energy Technology Data Exchange (ETDEWEB)

    Morris, G.A. [Rice Univ., Houston, TX (United States). Dept. of Space Physics and Astronomy

    1994-09-01

    Problem of creating synoptic maps from asynoptically gathered data has prompted the development of a number schemes, the most notable being the Kalman filter, Salby-Fourier technique, and constituent reconstruction. This thesis presents a new technique, called trajectory mapping, which employs a simple model of air parcel motion to create synoptic maps from asynoptically gathered data. Four sources of trajectory mapping errors were analyzed; results showed that (1) the computational error is negligible; (2) measurement uncertainties can result in errors which grow with time scales of a week; (3) isentropic approximations lead to errors characterized by time scales of a week; and (4) wind field inaccuracies can cause significant errors in individual parcel trajectories in a matter of hours. All the studies, however, indicated that while individual trajectory errors can grow rapidly, constituent distributions, such as on trajectory maps, are much more robust, maintaining a high level of accuracy for periods on the order of several weeks. This technique was successfully applied to a variety of problems:(1) dynamical wave- breaking events; (2) satellite data validation for both instrument accuracy and precision; and (3) accuracy of meteorological wind fields. Such demonstrations imply that trajectory mapping will become an important tool in answering questions of global change, particularly the issue of ozone depletion.

  7. Searching Trajectories by Regions of Interest

    KAUST Repository

    Shang, Shuo

    2017-03-22

    With the increasing availability of moving-object tracking data, trajectory search is increasingly important. We propose and investigate a novel query type named trajectory search by regions of interest (TSR query). Given an argument set of trajectories, a TSR query takes a set of regions of interest as a parameter and returns the trajectory in the argument set with the highest spatial-density correlation to the query regions. This type of query is useful in many popular applications such as trip planning and recommendation, and location based services in general. TSR query processing faces three challenges: how to model the spatial-density correlation between query regions and data trajectories, how to effectively prune the search space, and how to effectively schedule multiple so-called query sources. To tackle these challenges, a series of new metrics are defined to model spatial-density correlations. An efficient trajectory search algorithm is developed that exploits upper and lower bounds to prune the search space and that adopts a query-source selection strategy, as well as integrates a heuristic search strategy based on priority ranking to schedule multiple query sources. The performance of TSR query processing is studied in extensive experiments based on real and synthetic spatial data.

  8. Body weight trajectories and risk of oesophageal and gastric cardia adenocarcinomas: a pooled analysis of NIH-AARP and PLCO Studies.

    Science.gov (United States)

    Petrick, Jessica L; Kelly, Scott P; Liao, Linda M; Freedman, Neal D; Graubard, Barry I; Cook, Michael B

    2017-03-28

    Elevated body mass index (BMI, kg m(-2)) has been consistently associated with oesophageal adenocarcinoma (EA) and gastric cardia adenocarcinoma (GCA) incidence. However, effects of adiposity over the life course in relation to EA/GCA have not been thoroughly explored. We pooled two prospective cohort studies: NIH-AARP Diet and Health Study and Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, with data on 409 796 individuals (633 EA, 415 GCA). At baseline, participants reported their height and weight at ages 20 and 50 years, and current. Body mass index trajectories were determined using latent class analysis. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated using proportional hazards regression. Compared with individuals with a BMIobesity (⩾30 kg m(-2)) by age 50 was associated with increased risks of EA (HR=2.90, 95% CI: 1.67-5.04) and GCA (HR=4.07, 95% CI: 2.32-7.15), compared with individuals with a normal weight (⩾18.5-<25 kg m(-2)) trajectory. Weight gain of ⩾20 kg between age 20 and baseline was also associated with a two times increased risk of EA (HR=1.97, 95% CI: 1.43-2.73) and more modestly with GCA (HR=1.40, 95% CI: 0.96-2.05). Being overweight in early adulthood and weight gain later in life were each associated with increased risks of EA and GCA. This underscores the potential of weight control programs for reducing EA and GCA risk.

  9. Highly Excited Mesons, Linear Regge Trajectories and the Pattern of the Chiral Symmetry Realization

    CERN Document Server

    Shifman, M

    2007-01-01

    The chiral symmetry of QCD shows up in the linear Weyl--Wigner mode at short Euclidean distances or at high temperatures. On the other hand, low-lying hadronic states exhibit the nonlinear Nambu--Goldstone mode. An interesting question was raised as to whether the linear realization of the chiral symmetry is asymptotically restored for highly excited states. We address it in a number of ways. On the phenomenological side we argue that to the extent the meson Regge trajectories are observed to be linear and equidistant, the Weyl--Wigner mode is not realized. This picture is supported by quasiclassical arguments implying that the quark spin interactions in high excitations are weak, the trajectories are linear, and there is no chiral symmetry restoration. Then we use the string/gauge duality. In the top-down Sakai--Sugimoto construction the nonlinear realization of the chiral symmetry is built in. In the bottom-up AdS/QCD construction by Erlich et al., and Karch et al. the situation is more ambiguous. However, ...

  10. Integration of a real-time tumor monitoring system into gated proton spot-scanning beam therapy: An initial phantom study using patient tumor trajectory data

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, Taeko; Miyamoto, Naoki; Takao, Seishin; Nihongi, Hideaki; Toramatsu, Chie; Sutherland, Kenneth; Suzuki, Ryusuke; Ishikawa, Masayori; Maeda, Kenichiro [Department of Medical Physics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8638 (Japan); Shimizu, Shinichi; Kinoshita, Rumiko; Umegaki, Kikuo; Shirato, Hiroki [Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, 060-8648 (Japan); Fujii, Yusuke; Umezawa, Masumi [Hitachi, Ltd., Hitachi Research Laboratory, 7-2-1 Omika-cho, Hitachi-shi, Ibaraki 319-1221 (Japan)

    2013-07-15

    Purpose: In spot-scanning proton therapy, the interplay effect between tumor motion and beam delivery leads to deterioration of the dose distribution. To mitigate the impact of tumor motion, gating in combination with repainting is one of the most promising methods that have been proposed. This study focused on a synchrotron-based spot-scanning proton therapy system integrated with real-time tumor monitoring. The authors investigated the effectiveness of gating in terms of both the delivered dose distribution and irradiation time by conducting simulations with patients' motion data. The clinically acceptable range of adjustable irradiation control parameters was explored. Also, the relation between the dose error and the characteristics of tumor motion was investigated.Methods: A simulation study was performed using a water phantom. A gated proton beam was irradiated to a clinical target volume (CTV) of 5 Multiplication-Sign 5 Multiplication-Sign 5 cm{sup 3}, in synchronization with lung cancer patients' tumor trajectory data. With varying parameters of gate width, spot spacing, and delivered dose per spot at one time, both dose uniformity and irradiation time were calculated for 397 tumor trajectory data from 78 patients. In addition, the authors placed an energy absorber upstream of the phantom and varied the thickness to examine the effect of changing the size of the Bragg peak and the number of required energy layers. The parameters with which 95% of the tumor trajectory data fulfill our defined criteria were accepted. Next, correlation coefficients were calculated between the maximum dose error and the tumor motion characteristics that were extracted from the tumor trajectory data.Results: With the assumed CTV, the largest percentage of the data fulfilled the criteria when the gate width was {+-}2 mm. Larger spot spacing was preferred because it increased the number of paintings. With a prescribed dose of 2 Gy, it was difficult to fulfill the

  11. Interference, Reduced Action, and Trajectories

    Science.gov (United States)

    Floyd, Edward R.

    2007-09-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the trajectories of the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichromatic wave function’s trajectory. The quantum effective mass renders insight into the behavior of the trajectory. The trajectory in turn renders insight into quantum nonlocality.

  12. Growth Trajectories of Health Behaviors from Adolescence through Young Adulthood

    Directory of Open Access Journals (Sweden)

    Nora Wiium

    2015-10-01

    Full Text Available Based on nine waves of data collected during a period of 17 years (1990–2007, the present study explored different developmental trajectories of the following unhealthy behaviors: regular smoking, lack of regular exercise, lack of daily fruit intake, and drunkenness. A baseline sample of 1195 13-year-old pupils was from 22 randomly selected schools in the Hordaland County in western Norway. Latent class growth analysis revealed three developmental trajectories. The first trajectory was a conventional trajectory, comprising 36.3% of participants, who showed changes in smoking, physical exercise, fruit intake, and drunkenness consistent with the prevailing age specific norms of these behaviors in the Norwegian society at the time. The second trajectory was a passive trajectory, comprising 25.5% of participants, who reported low levels of both healthy and unhealthy behaviors during the 17-year period. The third trajectory was an unhealthy trajectory, comprising 38.2% of participants, who had high levels of unhealthy behaviors over time. Several covariates were examined, but only sex and mother’s and father’s educational levels were found to be significantly associated with the identified trajectories. While these findings need to be replicated in future studies, the identification of the different trajectories suggests the need to tailor intervention according to specific needs.

  13. Bohmian trajectory from the "classical" Schrödinger equation.

    Science.gov (United States)

    Sengupta, Santanu; Khatua, Munmun; Chattaraj, Pratim Kumar

    2014-12-01

    The quantum-classical correspondence is studied for a periodically driven quartic oscillator exhibiting integrable and chaotic dynamics, by studying the Bohmian trajectory of the corresponding "classical" Schrödinger equation. Phase plots and the Kolmogorov-Sinai entropy are computed and compared with the classical trajectory as well as the Bohmian trajectory obtained from the time dependent Schrödinger equation. Bohmian mechanics at the classical limit appears to mimick the behavior of a dissipative dynamical system.

  14. Trajectory Browser: An online tool for interplanetary trajectory analysis and visualization

    Science.gov (United States)

    Foster, C.

    The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center for finding preliminary trajectories to planetary bodies and for providing relevant launch date, time-of-flight and Δ V requirements. The site hosts a database of transfer trajectories from Earth to planets and small-bodies for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and Δ V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release in early 2013.

  15. Trajectory Optimization: OTIS 4

    Science.gov (United States)

    Riehl, John P.; Sjauw, Waldy K.; Falck, Robert D.; Paris, Stephen W.

    2010-01-01

    The latest release of the Optimal Trajectories by Implicit Simulation (OTIS4) allows users to simulate and optimize aerospace vehicle trajectories. With OTIS4, one can seamlessly generate optimal trajectories and parametric vehicle designs simultaneously. New features also allow OTIS4 to solve non-aerospace continuous time optimal control problems. The inputs and outputs of OTIS4 have been updated extensively from previous versions. Inputs now make use of objectoriented constructs, including one called a metastring. Metastrings use a greatly improved calculator and common nomenclature to reduce the user s workload. They allow for more flexibility in specifying vehicle physical models, boundary conditions, and path constraints. The OTIS4 calculator supports common mathematical functions, Boolean operations, and conditional statements. This allows users to define their own variables for use as outputs, constraints, or objective functions. The user-defined outputs can directly interface with other programs, such as spreadsheets, plotting packages, and visualization programs. Internally, OTIS4 has more explicit and implicit integration procedures, including high-order collocation methods, the pseudo-spectral method, and several variations of multiple shooting. Users may switch easily between the various methods. Several unique numerical techniques such as automated variable scaling and implicit integration grid refinement, support the integration methods. OTIS4 is also significantly more user friendly than previous versions. The installation process is nearly identical on various platforms, including Microsoft Windows, Apple OS X, and Linux operating systems. Cross-platform scripts also help make the execution of OTIS and post-processing of data easier. OTIS4 is supplied free by NASA and is subject to ITAR (International Traffic in Arms Regulations) restrictions. Users must have a Fortran compiler, and a Python interpreter is highly recommended.

  16. A Novel Semantic Matching Method for Indoor Trajectory Tracking

    Directory of Open Access Journals (Sweden)

    Sheng Guo

    2017-07-01

    Full Text Available The rapid development of smartphone sensors has provided rich indoor pedestrian trajectory data for indoor location-based applications. To improve the quality of these collected trajectory data, map matching methods are widely used to correct trajectories. However, these existing matching methods usually cannot achieve satisfactory accuracy and efficiency and have difficulty in exploiting the rich information contained in the obtained trajectory data. In this study, we proposed a novel semantic matching method for indoor pedestrian trajectory tracking. Similar to our previous work, pedestrian dead reckoning (PDR and human activity recognition (HAR are used to obtain the raw user trajectory data and the corresponding semantic information involved in the trajectory, respectively. To improve the accuracy and efficiency for user trajectory tracking, a semantic-rich indoor link-node model is then constructed based on the input floor plan, in which navigation-related semantics are extracted and formalized for the following trajectory matching. PDR and HAR are further utilized to segment the trajectory and infer the semantics (e.g., “Turn left”, “Turn right”, and “Go straight”. Finally, the inferred semantic information is matched with the semantic-rich indoor link-node model to derive the correct user trajectory. To accelerate the matching process, the semantics inferred from the trajectory are also assigned weights according to their relative importance. The experiments confirm that the proposed method achieves accurate trajectory tracking results while guaranteeing a high matching efficiency. In addition, the resulting semantic information has great application potential in further indoor location-based services.

  17. Going Ballistic: Bullet Trajectories

    Directory of Open Access Journals (Sweden)

    Amanda Wade

    2011-01-01

    Full Text Available This project seeks to answer at what angle does a gun marksman have to aim in order to hit the center of a target one meter off the ground and 1000 meters away? We begin by modeling the bullet's trajectory using Euler's method with the help of a Microsoft Excel spreadsheet solver, and then systematically search for the angle corresponding to the center of the target. It was found that a marksman shooting a target 1000 meters away and 1 meter off the ground has to aim the rifle 0.436° above horizontal to hit the center.

  18. A Design Research Study of a Curriculum and Diagnostic Assessment System for a Learning Trajectory on Equipartitioning

    Science.gov (United States)

    Confrey, Jere; Maloney, Alan

    2015-01-01

    Design research studies provide significant opportunities to study new innovations and approaches and how they affect the forms of learning in complex classroom ecologies. This paper reports on a two-week long design research study with twelve 2nd through 4th graders using curricular materials and a tablet-based diagnostic assessment system, both…

  19. A Design Research Study of a Curriculum and Diagnostic Assessment System for a Learning Trajectory on Equipartitioning

    Science.gov (United States)

    Confrey, Jere; Maloney, Alan

    2015-01-01

    Design research studies provide significant opportunities to study new innovations and approaches and how they affect the forms of learning in complex classroom ecologies. This paper reports on a two-week long design research study with twelve 2nd through 4th graders using curricular materials and a tablet-based diagnostic assessment system, both…

  20. Decoherence and the Branching of Chaos-less Classical Trajectory

    CERN Document Server

    Ishikawa, Takuji

    2016-01-01

    This study was started to know mysterious classicality of nuclei. This time, I found a new rule for decoherence. I used a model without chaos. As a result, it was shown that not only the intersection of classical trajectories but also branching of classical trajectories are needed for decoherence. In other words, it was shown that interactions between a main system and environments have to make enough branchings of classical trajectories of the main system for decoherence.

  1. Dynamical Casimir effect in Circuit QED for Nonuniform Trajectories

    CERN Document Server

    Corona-Ugalde, Paulina; Wilson, C M; Mann, Robert B

    2015-01-01

    We propose a generalization of the superconducting circuit simulation of the dynamical Casimir effect where we consider relativistically moving boundary conditions following different trajectories. We study the feasibility of the setup used in the past to simulate the dynamical Casimir effect to reproduce richer relativistic trajectories differing from purely sinusoidal ones. We show how different relativistic oscillatory trajectories of the boundaries of the same period and similar shape produce a rather different spectrum of particles characteristic of their respective motions.

  2. Trajectory attractors of equations of mathematical physics

    Energy Technology Data Exchange (ETDEWEB)

    Vishik, Marko I; Chepyzhov, Vladimir V [Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-08-31

    In this survey the method of trajectory dynamical systems and trajectory attractors is described, and is applied in the study of the limiting asymptotic behaviour of solutions of non-linear evolution equations. This method is especially useful in the study of dissipative equations of mathematical physics for which the corresponding Cauchy initial-value problem has a global (weak) solution with respect to the time but the uniqueness of this solution either has not been established or does not hold. An important example of such an equation is the 3D Navier-Stokes system in a bounded domain. In such a situation one cannot use directly the classical scheme of construction of a dynamical system in the phase space of initial conditions of the Cauchy problem of a given equation and find a global attractor of this dynamical system. Nevertheless, for such equations it is possible to construct a trajectory dynamical system and investigate a trajectory attractor of the corresponding translation semigroup. This universal method is applied for various types of equations arising in mathematical physics: for general dissipative reaction-diffusion systems, for the 3D Navier-Stokes system, for dissipative wave equations, for non-linear elliptic equations in cylindrical domains, and for other equations and systems. Special attention is given to using the method of trajectory attractors in approximation and perturbation problems arising in complicated models of mathematical physics. Bibliography: 96 titles.

  3. Quasiclassical calculation of the quasiparticle thermal conductivity in a mixed state

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Hiroto [Department of Physics, Okayama University, Okayama 700-8530 (Japan)]. E-mail: adachi@mp.okayama-u.ac.jp; Miranovic, Predrag [Department of Physics, University of Montenegro, Podgorica 81000 (Serbia); Ichioka, Masanori [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Machida, Kazushige [Department of Physics, Okayama University, Okayama 700-8530 (Japan)

    2007-03-15

    We report the result of calculation of the quasiparticle thermal conductivity {kappa}{sub xx}({nabla}T orthogonal B) in the vortex state of a two-dimensional superconductor. We compute {kappa}{sub xx} for both s-wave and d-wave superconductors, taking account of the spatial dependence of normal Green's function g, which is neglected in the previous studies using the Brandt-Pesch-Tewordt (BPT) method. Our results indicate that {kappa}{sub xx} based on the BPT method is slightly underestimated due to its incoherent spatial averaging procedure.

  4. Fluency, Accuracy, and Gender Predict Developmental Trajectories of Arithmetic Strategies

    Science.gov (United States)

    Carr, Martha; Alexeev, Natalia

    2011-01-01

    The purpose of this study was to determine whether there are different growth trajectories of arithmetic strategies and whether these trajectories result in different achievement outcomes. Longitudinal data were collected on 240 students who began the study as 2nd graders. In the 1st year of the study, the 2nd-grade students were assessed on…

  5. Risk factors associated with trajectories of mothers' depressive symptoms across the early parenting period: an Australian population-based longitudinal study.

    Science.gov (United States)

    Giallo, Rebecca; Cooklin, Amanda; Nicholson, Jan M

    2014-04-01

    Approximately 14 % of women experience depressive symptoms in the first postnatal year. Few studies have examined the persistence of symptoms beyond this time. This study aims to (a) assess the course of women's depressive symptoms from the first postnatal year to when their children were aged 6-7 years, (b) identify distinct groups of women defined by their symptom trajectories over time, and (c) identify antenatal and early postnatal risk factors associated with persistent symptoms. Data from 4,879 women participating in the Longitudinal Study of Australian Children were analysed using latent growth modelling and logistic regression to identify risk factors associated with class membership. For the overall sample, depressive symptoms were highest during the first postnatal year and then gradually decreased over 6-7 years. Two distinct classes were identified with the majority of women (84 %) reporting minimal symptoms over time, and 16 % experiencing persistently high symptoms. Risk factors were younger maternal age, being from a non-English speaking background, not completing high school, having a past history of depression, antidepressant use during pregnancy, child development problems, lower parenting self-efficacy, poor relationship quality, and stressful life events. This research identifies risk factors that may predispose mothers to enduring depressive symptoms, offering opportunities for early identification and targeted early intervention.

  6. Solution space analysis of Double Lunar-Swingby periodic trajectory

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Double Lunar-Swingby(DLS)periodic trajectory is a type of large-scale trajectory in Restricted Three-Body Problem framework.First,the principium of the DLS periodic trajectory is studied,and a preliminary design of the DLS trajectory is developed by the Patched Conic method.Second,the solution space of the DLS periodic trajectory is discussed in detail and in combination with numerical simulation,a distribution about orbital parameter relationship in the solution space is given.Finally,the variations of the orbital elements with different rotation angular velocities of geocentric apsidal line are found,and two typical orbits are given according to three reference frames.It is shown that Patched Conic method is feasible for the DLS periodic trajectory solution space analysis,and the conclusions will be valuable to the deep-space exploration orbit design in future.

  7. Quasi-classical modeling of molecular quantum-dot cellular automata multidriver gates

    Science.gov (United States)

    Rahimi, Ehsan; Nejad, Shahram Mohammad

    2012-05-01

    Molecular quantum-dot cellular automata (mQCA) has received considerable attention in nanoscience. Unlike the current-based molecular switches, where the digital data is represented by the on/off states of the switches, in mQCA devices, binary information is encoded in charge configuration within molecular redox centers. The mQCA paradigm allows high device density and ultra-low power consumption. Digital mQCA gates are the building blocks of circuits in this paradigm. Design and analysis of these gates require quantum chemical calculations, which are demanding in computer time and memory. Therefore, developing simple models to probe mQCA gates is of paramount importance. We derive a semi-classical model to study the steady-state output polarization of mQCA multidriver gates, directly from the two-state approximation in electron transfer theory. The accuracy and validity of this model are analyzed using full quantum chemistry calculations. A complete set of logic gates, including inverters and minority voters, are implemented to provide an appropriate test bench in the two-dot mQCA regime. We also briefly discuss how the QCADesigner tool could find its application in simulation of mQCA devices.

  8. Centrifugally driven relativistic dynamics on curved trajectories

    CERN Document Server

    Rogava, A; Osmanov, Z; Rogava, Andria; Dalakishvili, George; Osmanov, Zaza

    2003-01-01

    Motion of test particles along rotating curved trajectories is considered. The problem is studied both in the laboratory and the rotating frames of reference. It is assumed that the system rotates with the constant angular velocity $\\omega = const$. The solutions are found and analyzed for the case when the form of the trajectory is given by an Archimedes spiral. It is found that particles can reach infinity while they move along these trajectories and the physical interpretation of their behaviour is given. The analogy of this idealized study with the motion of particles along the curved rotating magnetic field lines in the pulsar magnetosphere is pointed out. We discuss further physical development (the conserved total energy case, when $\\omega \

  9. Debt trajectories and mental health.

    Science.gov (United States)

    Hojman, Daniel A; Miranda, Álvaro; Ruiz-Tagle, Jaime

    2016-10-01

    In the last few decades, there was a marked increase in consumer debt in the United States, Latin America and other emerging countries, spurring a debate about the real costs and benefits of household credit. Using a unique longitudinal dataset with detailed health and balance sheet information from a large sample of 10,900 Chilean households we study the relationship between debt trajectories in a three-year time window and mental health. We find that depressive symptoms are higher for those who have been persistently over-indebted, followed by those who transit from moderate to high debt levels. We also find that those who transition from over-indebtedness to moderate debt levels have no additional depressive symptoms compared to those with trajectories of moderate debt throughout (never over-indebted). This suggests that the debt-related contribution to depressive symptoms vanishes as debt levels fall. The association between debt and depressive symptoms seems to be driven by non-mortgage debt -primarily consumer credit- or late mortgage payments; secured debt (secured by collateral) per se is not associated with depressive symptoms. Policy interventions to reduce the negative association of over-indebtedness on mental health are discussed.

  10. Trajectories of Marital Conflict Across the Life Course: Predictors and Interactions With Marital Happiness Trajectories.

    Science.gov (United States)

    Kamp Dush, Claire M; Taylor, Miles G

    2012-03-01

    Using typologies outlined by Gottman and Fitzpatrick as well as institutional and companionate models of marriage, the authors conducted a latent class analysis of marital conflict trajectories using 20 years of data from the Marital Instability Over the Life Course study. Respondents were in one of three groups: high, medium (around the mean), or low conflict. Several factors predicted conflict trajectory group membership; respondents who believed in lifelong marriage and shared decisions equally with their spouse were more likely to report low and less likely to report high conflict. The conflict trajectories were intersected with marital happiness trajectories to examine predictors of high and low quality marriages. A stronger belief in lifelong marriage, shared decision making, and husbands sharing a greater proportion of housework were associated with an increased likelihood of membership in a high happiness, low conflict marriage, and a decreased likelihood of a low marital happiness group.

  11. Thoracostomy tube function not trajectory dictates reintervention.

    Science.gov (United States)

    Kugler, Nathan W; Carver, Thomas W; Knechtges, Paul; Milia, David; Goodman, Lawrence; Paul, Jasmeet S

    2016-12-01

    Hemothorax and/or pneumothorax can be managed successfully managed with tube thoracostomy (TT) in the majority of cases. Improperly placed tubes are common with rates near 30%. This study aimed to determine whether TT trajectory affects the rate of secondary intervention. A retrospective review of all adult trauma patients undergoing TT placement over a 4-y period was performed. TT trajectory was classified as ideal, nonideal, or kinked-based on anterior-posterior chest x-ray. TTs with sentinel port outside the thoracic cavity were excluded. The primary outcome was any secondary intervention. Four-hundred eighty-six patients and a total of 547 hemithoraces underwent placement and met inclusion criteria. The majority of patients were male (76%), with a median age of 41 y, and majority suffered blunt trauma ideal trajectory was identified in 429 (78.4%). Kinked TTs were noted in 33 (6%) hemothoraces with a 45.5% replacement rate. Review with staff demonstrates inherent bias to replace kinked TTs. The overall secondary intervention rate was 27.8%. Kinked TTs were removed from final analysis due to treatment bias. Subsequent analysis demonstrated no significant difference between ideal and nonideal trajectories (25.1% versus 34.1%, P = 0.09). Intrathoracic trajectory of nonkinked TTs with the sentinel port within the thoracic cavity does not affect secondary intervention rates, including the rate of surgical intervention. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Periodic billiard trajectories in polygons: generating mechanisms

    Science.gov (United States)

    Vorobets, Ya B.; Gal'perin, G. A.; Stepin, Anatolii M.

    1992-06-01

    CONTENTSIntroduction §1. Billiard trajectories in a plane domain §2. Fagnano's problem. Mechanical interpretations of periodic trajectories in triangles §3. An extremal property of billiard trajectories. Birkhoff's theorem. The non-existence of a unified construction of periodic trajectories in obtuse triangles §4. 'Perpendicular' trajectories in obtuse triangles of special shape §5. 'Perpendicular' trajectories in rational polygons and polyhedra §6. Stable trajectories §7. Stable perpendicular trajectories §8. Isolated trajectories §9. Isolated trajectories in acute and obtuse triangles. The bifurcation diagram of isolated trajectories (a 'hang-glider' configuration) §10. The density of F-triangles in a neighbourhood of (0, 0) §11. Generalization of the construction of isolated trajectories in obtuse triangles §12. Stable and unstable billiard trajectories in plane Weyl chambers §13. A criterion for the stability of periodic trajectories in a regular hexagonConclusionReferences

  13. Interference, reduced action, and trajectories

    CERN Document Server

    Floyd, E R

    2006-01-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichromatic wave function's trajectory. The quantum effective mass renders insight into the behavior of the trajectory. The trajectory in turn renders insight into quantum nonlocality.

  14. Abrasive Particle Trajectories and Material Removal Non-Uniformity during CMP and Filtration Characteristics of CMP Slurries - A Simulation and Experimental Study

    Science.gov (United States)

    Rastegar, Vahid

    Nanoscale finishing and planarization are integral process steps in multilevel metallization designs for integrated circuit (IC) manufacturing since it is necessary to ensure local and global surface planarization at each metal layer before depositing the next layer. Chemical mechanical planarization (CMP) has been widely recognized as the most promising technology to eliminate topographic variation and has allowed the construction of multilevel interconnection structures with a more regularly stacked sequence, resulting in better device performance [1]. Understanding fundamental of the CMP mechanisms can offer guidance to the control and optimization of the polishing processes. CMP kinematics based on slurry distribution and particle trajectories have a significant impact on MRR profiles. In this work a mathematical model to describe particle trajectories during chemical mechanical polishing was developed and extended to account for the effect of larger particles, particle location changes due to slurry dispensing and in-situ conditioning. Material removal rate (MRR) and within wafer non-uniformity (WIWNU) were determined based on the calculated particle trajectory densities. Rotary dynamics and reciprocating motion were optimized to obtain best MRR uniformity. Edge-fast MRR profile was discussed based on mechanical aspect of CMP. Using the model, we also investigated the effect of variable rotational speeds of wafer and pad, and of large particles on WIWNU and scratch growth. It was shown that the presence of even a small portion of large particles can deteriorate the WIWNU significantly and also lead to more scratches. Furthermore, it was shown that the in-situ conditioning improves the uniformity of the polished wafers. Furthermore, a combined experimental and computational study of fibrous filters for removal of larger abrasive particles from aqueous dispersions, essential to minimize defects during chemical mechanical polishing, was performed. Dilute aqueous

  15. The role of study and work in cannabis use and dependence trajectories among young adult frequent cannabis users

    Directory of Open Access Journals (Sweden)

    Nienke eLiebregts

    2013-08-01

    Full Text Available Life course theory considers events in study and work as potential turning points in deviance, including illicit drug use. This qualitative study explores the role of occupational life in cannabis use and dependence in young adults. Two and three years after the initial structured interview, 47 at baseline frequent cannabis users were interviewed in-depth about the dynamics underlying changes in their cannabis use and dependence. Overall, cannabis use and dependence declined, including interviewees who quit using cannabis completely, in particular with students, both during their study and after they got employed. Life course theory appeared to be a useful framework to explore how and why occupational life is related to cannabis use and dependence over time. Our study showed that life events in this realm are rather common in young adults and can have a strong impact on cannabis use. While sometimes changes in use are temporary, turning points can evolve from changes in educational and employment situations; an effect that seems to be related to the consequences of these changes in terms of amount of leisure time and agency (i.e. feelings of being in control.

  16. Developmental trajectories and reciprocal associations between career adaptability and vocational identity : A three-wave longitudinal study with adolescents

    NARCIS (Netherlands)

    Negru-Subtirica, Oana; Pop, Eleonora Ioana; Crocetti, Elisabetta

    2015-01-01

    The purpose of this longitudinal study was two-fold. First, we investigated patterns of stability and change in career adaptability and vocational identity in adolescents. Second, we examined reciprocal associations between career adaptability and vocational identity. In addressing both research aim

  17. Intertwining Lexical and Conceptual Learning Trajectories--A Design Research Study on Dual Macro-Scaffolding towards Percentages

    Science.gov (United States)

    Pöhler, Birte; Prediger, Susanne

    2015-01-01

    Monolingual or multilingual students with low academic language proficiency need to acquire conceptual understanding for percentages and the language to communicate about them. The design research study explores how these two learning goals can be fostered by a macro-scaffolding approach for seventh grade students. The dual hypothetical learning…

  18. Intertwining Lexical and Conceptual Learning Trajectories--A Design Research Study on Dual Macro-Scaffolding towards Percentages

    Science.gov (United States)

    Pöhler, Birte; Prediger, Susanne

    2015-01-01

    Monolingual or multilingual students with low academic language proficiency need to acquire conceptual understanding for percentages and the language to communicate about them. The design research study explores how these two learning goals can be fostered by a macro-scaffolding approach for seventh grade students. The dual hypothetical learning…

  19. The Developmental Trajectory of Perceived Self-Regulation, Personal Interest, and General Achievement throughout High School: A Longitudinal Study

    Science.gov (United States)

    Helle, Laura; Laakkonen, Eero; Tuijula, Tiina; Vermunt, Jan D.

    2013-01-01

    Background: Our interest in perceived self-regulation of learning arose in the context of educational reform. After decades of stability, the Finnish high school system underwent reform in the 1990s, with a significant emphasis being placed on promoting student self-regulation of learning. Aims: The purposes of the study were (1) to evaluate…

  20. Foreign language learning as a complex dynamic process: A microgenetic case study of a Chinese child's English learning trajectory

    NARCIS (Netherlands)

    Sun, He; Steinkrauss, Rasmus; van der Steen, Steffie; Cox, Ralf; de Bot, Kees

    2016-01-01

    The current study focuses on one child's (male, 3 years old) learning behaviors in an English as a Foreign Language classroom, and explores the coordination and developmental patterns of his nonverbal (gestures and body language) and verbal (verbal repetition and verbal responses) learning behaviors

  1. Foreign language learning as a complex dynamic process: A microgenetic case study of a Chinese child's English learning trajectory

    NARCIS (Netherlands)

    Sun, He; Steinkrauss, Rasmus; van der Steen, Steffie; Cox, Ralf; de Bot, Kees

    2016-01-01

    The current study focuses on one child's (male, 3 years old) learning behaviors in an English as a Foreign Language classroom, and explores the coordination and developmental patterns of his nonverbal (gestures and body language) and verbal (verbal repetition and verbal responses) learning behaviors

  2. Family and Neighbourhood Socioeconomic Inequalities in Childhood Trajectories of BMI and Overweight: Longitudinal Study of Australian Children

    NARCIS (Netherlands)

    P.W. Jansen (Pauline); F.K.F. Mensah (Fane ); J.M. Nicholson (Jan ); M. Wake (Melissa)

    2013-01-01

    textabstractBackground:Socioeconomic inequalities in longitudinal patterning of childhood overweight could cause marked differentials in total burden by adulthood. This study aims to determine timing and strength of the association between socioeconomic status (SES) and children's body mass index (B

  3. Generation of NEP heliocentric trajectory data

    Science.gov (United States)

    Horsewood, J. L.; Brice, K. B.

    1972-01-01

    A study, designed to generate representative nuclear electric propulsion data for rendezvous missions to the comet Encke using the variational calculus program HILTOP, is presented. Other purposes of the study include a comparison of the HILTOP data with equivalent data generated with QUICKTOP program and to propose approaches for storing and subsequently accessing the optimum trajectory and performance data in the QUICKLY program.

  4. Trajectories of Depression Symptoms among Older Youths Exiting Foster Care

    Science.gov (United States)

    Munson, Michelle R.; McMillen, Curtis

    2010-01-01

    The purpose of this study was to determine the trajectories of depressive symptoms as older youths from the foster care system mature while also examining the correlates of these trajectories. Data came from a longitudinal study of 404 youths from the foster care system in Missouri, who were interviewed nine times between their 17th and 19th…

  5. Exploring Categorical Body Mass Index Trajectories in Elementary School Children

    Science.gov (United States)

    Moreno-Black, Geraldine; Boles, Shawn; Johnson-Shelton, Deb; Evers, Cody

    2016-01-01

    Background: Studies of body mass index (BMI) change have focused on understanding growth trajectories from childhood to adolescence and adolescence to adulthood, but few have explored BMI trajectories solely in elementary (grades K-5) school children. This report complements these studies by exploring changes in obesity status using analytic…

  6. Predictors of Latent Trajectory Classes of Physical Dating Violence Victimization

    Science.gov (United States)

    Brooks-Russell, Ashley; Foshee, Vangie A.; Ennett, Susan T.

    2013-01-01

    This study identified classes of developmental trajectories of physical dating violence victimization from grades 8 to 12 and examined theoretically-based risk factors that distinguished among trajectory classes. Data were from a multi-wave longitudinal study spanning 8th through 12th grade (n = 2,566; 51.9 % female). Growth mixture models were…

  7. Trajectory metaheuristic algorithms to optimize problems combinatorics

    Directory of Open Access Journals (Sweden)

    Natalia Alancay

    2016-12-01

    Full Text Available The application of metaheuristic algorithms to optimization problems has been very important during the last decades. The main advantage of these techniques is their flexibility and robustness, which allows them to be applied to a wide range of problems. In this work we concentrate on metaheuristics based on Simulated Annealing, Tabu Search and Variable Neighborhood Search trajectory whose main characteristic is that they start from a point and through the exploration of the neighborhood vary the current solution, forming a trajectory. By means of the instances of the selected combinatorial problems, a computational experimentation is carried out that illustrates the behavior of the algorithmic methods to solve them. The main objective of this work is to perform the study and comparison of the results obtained for the selected trajectories metaheuristics in its application for the resolution of a set of academic problems of combinatorial optimization.

  8. Romantic attraction and adolescent smoking trajectories.

    Science.gov (United States)

    Pollard, Michael S; Tucker, Joan S; Green, Harold D; Kennedy, David P; Go, Myong-Hyun

    2011-12-01

    Research on sexual orientation and substance use has established that lesbian, gay, and bisexual (LGB) individuals are more likely to smoke than heterosexuals. This analysis furthers the examination of smoking behaviors across sexual orientation groups by describing how same- and opposite-sex romantic attraction, and changes in romantic attraction, are associated with distinct six-year developmental trajectories of smoking. The National Longitudinal Study of Adolescent Health dataset is used to test our hypotheses. Multinomial logistic regressions predicting smoking trajectory membership as a function of romantic attraction were separately estimated for men and women. Romantic attraction effects were found only for women. The change from self-reported heterosexual attraction to lesbian or bisexual attraction was more predictive of higher smoking trajectories than was a consistent lesbian or bisexual attraction, with potentially important differences between the smoking patterns of these two groups.

  9. The trajectory of the blood DNA methylome ageing rate is largely set before adulthood: evidence from two longitudinal studies.

    Science.gov (United States)

    Kananen, L; Marttila, S; Nevalainen, T; Kummola, L; Junttila, I; Mononen, N; Kähönen, M; Raitakari, O T; Hervonen, A; Jylhä, M; Lehtimäki, T; Hurme, M; Jylhävä, J

    2016-06-01

    The epigenetic clock, defined as the DNA methylome age (DNAmAge), is a candidate biomarker of ageing. In this study, we aimed to characterize the behaviour of this marker during the human lifespan in more detail using two follow-up cohorts (the Young Finns study, calendar age i.e. cAge range at baseline 15-24 years, 25-year-follow-up, N = 183; The Vitality 90+ study, cAge range at baseline 19-90 years, 4-year-follow-up, N = 48). We also aimed to assess the relationship between DNAmAge estimate and the blood cell distributions, as both of these measures are known to change as a function of age. The subjects' DNAmAges were determined using Horvath's calculator of epigenetic cAge. The estimate of the DNA methylome age acceleration (Δ-cAge-DNAmAge) demonstrated remarkable stability in both cohorts: the individual rank orders of the DNAmAges remained largely unchanged during the follow-ups. The blood cell distributions also demonstrated significant intra-individual correlation between the baseline and follow-up time points. Interestingly, the immunosenescence-associated features (CD8+CD28- and CD4+CD28- cell proportions and the CD4/CD8 cell ratio) were tightly associated with the estimate of the DNA methylome age. In summary, our data demonstrate that the general level of Δ-cAge-DNAmAge is fixed before adulthood and appears to be quite stationary thereafter, even in the oldest-old ages. Moreover, the blood DNAmAge estimate seems to be tightly associated with ageing-associated shifts in blood cell composition, especially with those that are the hallmarks of immunosenescence. Overall, these observations contribute to the understanding of the longitudinal aspects of the DNAmAge estimate.

  10. The health seeking trajectories of Malaysian women and their husbands in delay cases of breast cancer: a qualitative study.

    Science.gov (United States)

    Yusoff, Nasir; Taib, Nur Aishah Mohd; Ahmad, Aini

    2011-01-01

    The aim of this study was to assess why women delay in getting treatment (i.e. surgery) for breast cancer, as well as to explore on what type of issues are involved in such delay cases. Basic interpretative of qualitative methodology was applied to construct the reality of delay phenomena, and its interaction with social worlds. Six themes were identified: new conception of breast cancer treatment, psychological defenses, health support system, symtomatology experience, model and barriers. The delay issue in breast cancer requires attention as a multidimensional problem as this will facilitate more comprehensive and effective intervention to reduce delay.

  11. Socioeconomic Status and Trajectory of Overweight from Birth to Mid-Childhood: The Early Childhood Longitudinal Study-Birth Cohort

    OpenAIRE

    Jones-Smith, Jessica C; Marlowe Gates Dieckmann; Laura Gottlieb; Jessica Chow; Fernald, Lia C. H.

    2014-01-01

    OBJECTIVE: Our objective was to use longitudinal data from a US birth cohort to test whether the probability of overweight or obesity during the first 6 years of life varied according to socioeconomic status. DESIGN AND METHODS: Using six waves of longitudinal data from full-term children in the Early Childhood Longitudinal Study-Birth Cohort (2001-2007; n≈4,950), we examined the prevalence of overweight or obesity (Body Mass Index (BMI)>2 standard deviations above age- and sex- specific WHO ...

  12. Application of GPS Trajectory Data for Investigating the Interaction between Human Activity and Landscape Pattern: A Case Study of the Lijiang River Basin, China

    Directory of Open Access Journals (Sweden)

    Jun Li

    2016-06-01

    Full Text Available The interaction between human activity and landscape pattern has been a hot research topic during the last few decades. However, scholars used to measure human activity by social, economic and humanistic indexes. These indexes cannot directly reflect human activity and are not suitable for fine-grained analysis due to the coarse spatial resolution. In view of the above problems, this paper proposes a method that obtains the intensity of human activity from GPS trajectory data, collects landscape information from remote sensing images and further analyzes the interaction between human activity and landscape pattern at a fine-grained scale. The Lijiang River Basin is selected as the study area. Experimental results show that human activity and landscape pattern interact synergistically in this area. Built-up land and water boost human activity, while woodland restrains human activity. The effect of human activity on landscape pattern differs by the land cover category. Overall, human activities make natural land, such as woodland and water, scattered and fragmented, but cause man-built land, such as built-up land and farmland, clustered and regular. Nevertheless, human activities inside and outside urban areas are the opposite. The research findings in this paper are helpful for designing and implementing sustainable management plans.

  13. Urban water trajectories

    CERN Document Server

    Allen, Adriana; Hofmann, Pascale; Teh, Tse-Hui

    2017-01-01

    Water is an essential element in the future of cities. It shapes cities’ locations, form, ecology, prosperity and health. The changing nature of urbanisation, climate change, water scarcity, environmental values, globalisation and social justice mean that the models of provision of water services and infrastructure that have dominated for the past two centuries are increasingly infeasible. Conventional arrangements for understanding and managing water in cities are being subverted by a range of natural, technological, political, economic and social changes. The prognosis for water in cities remains unclear, and multiple visions and discourses are emerging to fill the space left by the certainty of nineteenth century urban water planning and engineering. This book documents a sample of those different trajectories, in terms of water transformations, option, services and politics. Water is a key element shaping urban form, economies and lifestyles, part of the ongoing transformation of cities. Cities are face...

  14. Trajectories for Novel and Detailed Traffic Information

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Torp, Kristian

    2012-01-01

    Trajectories based on GPS tracks have been studied for a number of years but only to a limited degree been used for analyzing and monitoring traffic. This paper shows how novel and important information about traffic can be computed from trajectories. Concretely the paper proposes to compute...... to analyzing individual intersections that enables traffic analysts to compute queue lengths and estimated time to pass an intersection. Finally, the paper uses associative rule mining for evaluating green waves on road stretches. Such information can be used to verify that signalized intersections......, extracting this information requires no expensive changes to the road-network infrastructure, which is a problem with the technologies currently used....

  15. Developmental Trajectories for Visuo-Spatial Attention are Altered by Prenatal Alcohol Exposure: A Longitudinal FMRI Study.

    Science.gov (United States)

    Gautam, P; Nuñez, S C; Narr, K L; Mattson, S N; May, P A; Adnams, C M; Riley, E P; Jones, K L; Kan, E C; Sowell, E R

    2015-12-01

    Functional magnetic resonance imaging (fMRI) reveals brain activation abnormalities during visuo-spatial attention and working memory among those with fetal alcohol spectrum disorders (FASD) in cross-sectional reports, but little is known about how activation changes over time during development within FASD or typically developing children. We studied 30 controls and 31 individuals with FASD over 2 years (7-14 years at first participation) with a total of 122 scans, as part of the Collaborative Initiative on Fetal Alcohol Spectrum Disorders. Despite comparable performance, there were significant group differences in visuo-spatial activation over time bilaterally in frontal, parietal, and temporal regions. Controls showed an increase in signal intensity in these multiple regions whereas FASD participants showed a decrease in brain activation. Effects were also found in 2 small independent samples from the USA, corroborating the findings from the larger group. Results suggest that the long-lasting effect of prenatal alcohol may impact the maturation of visuo-spatial attention and differentiate those with FASD from controls. Based on this first longitudinal fMRI study in FASD children, our novel findings suggest a possible neural mechanism for attention deficits common among individuals with FASD.

  16. Adiposity Trajectory and Its associations with Plasma Adipokine Levels in Children and Adolescents – A Prospective Cohort Study

    Science.gov (United States)

    Li, Shenghui; Liu, Rong; Arguelles, Lester; Wang, Guoying; Zhang, Jun; Shen, Xiaoming; Wang, Xiaobin

    2015-01-01

    Objective This study aimed to examine the associations of longitudinal adiposity measures with two adipokines, leptin and adiponectin, and their ratio in children and adolescents. Methods A total of 953 children and adolescents participated in a 6-year longitudinal study. Body mass index (BMI), percentage body fat (%BF), and fat mass index (FMI) were used to assess adiposity status. Results After adjusting for possible confounders, our regression models revealed that BMI, %BF, and FMI, in both the baseline and follow-up survey, were independently associated with a higher level of leptin and the leptin/adiponectin ratio at the follow-up survey, whereas the significant association with adiponectin only partly existed in adiposity measures at the follow-up visit. Moreover, the longitudinal change in adiposity measures was found to be a significant predictor for follow-up plasma adipokine levels. Compared with the low→low group, the medium→medium group, up-trend group, and high→high group all showed a significantly increased level of leptin and leptin/adiponectin ratio. The up-trend group and high→high group also had significantly decreased adiponectin levels. Conclusions Our findings highlight the importance of adiposity surveillance and the utility of adipokines as biomarkers for adverse metabolic consequences of childhood adiposity. PMID:26704698

  17. Developmental trajectories of EEG sleep slow wave activity as a marker for motor skill development during adolescence: a pilot study.

    Science.gov (United States)

    Lustenberger, Caroline; Mouthon, Anne-Laure; Tesler, Noemi; Kurth, Salome; Ringli, Maya; Buchmann, Andreas; Jenni, Oskar G; Huber, Reto

    2017-01-01

    Reliable markers for brain maturation are important to identify neural deviations that eventually predict the development of mental illnesses. Recent studies have proposed topographical EEG-derived slow wave activity (SWA) during NREM sleep as a mirror of cortical development. However, studies about the longitudinal stability as well as the relationship with behavioral skills are needed before SWA topography may be considered such a reliable marker. We examined six subjects longitudinally (over 5.1 years) using high-density EEG and a visuomotor learning task. All subjects showed a steady increase of SWA at a frontal electrode and a decrease in central electrodes. Despite these large changes in EEG power, SWA topography was relatively stable within each subject during development indicating individual trait-like characteristics. Moreover, the SWA changes in the central cluster were related to the development of specific visuomotor skills. Taken together with the previous work in this domain, our results suggest that EEG sleep SWA represents a marker for motor skill development and further supports the idea that SWA mirrors cortical development during childhood and adolescence. © 2016 Wiley Periodicals, Inc.

  18. Tracing developmental trajectories of oppositional defiant behaviors in preschool children.

    Directory of Open Access Journals (Sweden)

    Lourdes Ezpeleta

    Full Text Available Previous studies on developmental trajectories have used ad hoc definitions of oppositional defiant behaviors (ODB, which makes it difficult to compare results. This article defines developmental trajectories of ODB from ages 3-5 based on five different standard measurements derived from three separate instruments.A sample of 622 three-year-old preschoolers, followed up at ages 4, 5, and 6, was assessed with the five measures of oppositionality answered by parents and teachers. Growth-Mixture-Modeling (GMM estimated separate developmental trajectories for each ODB measure for ages 3 to 5.The number of classes-trajectories obtained in each GMM depended on the ODB measure, but two clear patterns emerged: four trajectories (persistent low, decreasers, increasers/high increasers, persistent moderate/persistent high or three trajectories (persistent low, decreasers, increasers/high increasers. Persistent high trajectories accounted for 4.4%-9.5% of the children. The trajectories emerging from the different ODB measures at ages 3 to 5 discriminated disruptive disorders, comorbidity, use of services, and impairment at age 6, and globally showed a similar pattern, summarizing longitudinal information on oppositionality in preschool children in a similar way.Trajectories resulting from standard scales of the questionnaires have predictive validity for identifying relevant clinical outcomes, but are measure-specific. The results contribute to knowledge about the development of ODB in preschool children.

  19. Tracing developmental trajectories of oppositional defiant behaviors in preschool children.

    Science.gov (United States)

    Ezpeleta, Lourdes; Granero, Roser; de la Osa, Núria; Navarro, José Blas; Penelo, Eva; Domènech, Josep M

    2014-01-01

    Previous studies on developmental trajectories have used ad hoc definitions of oppositional defiant behaviors (ODB), which makes it difficult to compare results. This article defines developmental trajectories of ODB from ages 3-5 based on five different standard measurements derived from three separate instruments. A sample of 622 three-year-old preschoolers, followed up at ages 4, 5, and 6, was assessed with the five measures of oppositionality answered by parents and teachers. Growth-Mixture-Modeling (GMM) estimated separate developmental trajectories for each ODB measure for ages 3 to 5. The number of classes-trajectories obtained in each GMM depended on the ODB measure, but two clear patterns emerged: four trajectories (persistent low, decreasers, increasers/high increasers, persistent moderate/persistent high) or three trajectories (persistent low, decreasers, increasers/high increasers). Persistent high trajectories accounted for 4.4%-9.5% of the children. The trajectories emerging from the different ODB measures at ages 3 to 5 discriminated disruptive disorders, comorbidity, use of services, and impairment at age 6, and globally showed a similar pattern, summarizing longitudinal information on oppositionality in preschool children in a similar way. Trajectories resulting from standard scales of the questionnaires have predictive validity for identifying relevant clinical outcomes, but are measure-specific. The results contribute to knowledge about the development of ODB in preschool children.

  20. Entry Into a Care Trajectory

    Directory of Open Access Journals (Sweden)

    Normand Carpentier

    2013-06-01

    Full Text Available A broad range of services are developing in response to the needs of an aging population. Although most interventions are carried out in the patient’s living environment—at the heart of society—few studies on service utilization refer to social theory. This paper suggests that studies on older people with chronic health conditions would benefit from a stronger theoretical foundation. Drawing on 15 in-depth interviews, it highlights the relevance of individualization processes and the network society, 2 central theoretical concerns in sociology. The research provides a unique perspective on the entry into the care trajectory and expands our comprehension of the emergence of a social organization that can respond to the needs of elderly patients. Data of this nature may be useful in service planning and the development of a care-centered approach.

  1. Trajectory of chemotherapy for patients with EGFR wild-type advanced pulmonary adenocarcinoma: a single-institution retrospective study

    Science.gov (United States)

    Minami, Seigo; Ogata, Yoshitaka; Ihara, Shouichi; Yamamoto, Suguru; Komuta, Kiyoshi

    2017-01-01

    Background Pulmonary adenocarcinoma, recently benefited by new cytotoxic and molecularly targeted drugs, has been classified by driver mutations, such as EGFR mutations. The aim of this study was to research the proportions of patients treated with first- to third-line chemotherapy and to find influential factors for the introduction of chemotherapy and survival benefit from chemotherapy. Materials and methods Data were collected retrospectively on patients who met the following criteria: adenocarcinoma, diagnosed between June 2007 and March 2015 at our hospital, stage IIIB or IV, and EGFR wild type. A nonchemotherapy group of patients who did not receive chemotherapy was compared with a chemotherapy group of patients who received it. The patients who had received first- to third-line chemotherapy between June 2007 and November 2015 at our hospital were also analyzed. Results During the study period, 46 patients did not receive chemotherapy, while 148, 89, and 48 received first-, second- and third-line chemotherapy, respectively. As predictive factors for unlikely chemotherapy, multivariate logistic analysis detected Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥2, hemoglobin <13.2 g/dL, creatinine clearance (Ccr) <50.4 mL/min, and CRP ≥0.53 mg/dL. As factors predicting shorter survival after chemotherapy, multivariate Cox proportional-hazard analyses detected age ≥75 years, ECOG PS ≥2, lower lymphocyte counts, and higher CRP for the first line; female, higher neutrophil counts, lower lymphocyte counts, reduced Ccr, hyponatremia, and shorter interval between first- and second-line chemotherapy for the second line; and age ≥75 years, body mass index <18.5 kg/m2, higher neutrophil counts, lower lymphocyte counts, hyponatremia, higher lactate dehydrogenase, and higher CRP for the third line. Conclusion Approximately 76% of patients were treated with first-line chemotherapy. Of those patients, 61% and 34% proceeded to second- and third

  2. Prospective cohort study of general and central obesity, weight change trajectory and risk of major cancers among Chinese women.

    Science.gov (United States)

    Liu, Ying; Warren Andersen, Shaneda; Wen, Wanqing; Gao, Yu-Tang; Lan, Qing; Rothman, Nathaniel; Ji, Bu-Tian; Yang, Gong; Xiang, Yong-Bing; Shu, Xiao-Ou; Zheng, Wei

    2016-10-01

    General obesity, typically measured using body mass index (BMI), has been associated with an increased risk of several cancers. However, few prospective studies have been conducted in Asian populations. Although central obesity, often measured using waist-hip ratio (WHR), is more predictive for type 2 diabetes and cardiovascular diseases (CVD) risk than BMI, knowledge of its association with cancer incidence is limited. In a cohort of 68,253 eligible Chinese women, we prospectively investigated the association of BMI, WHR and weight change during adulthood with risk of overall cancer and major site-specific cancers using multivariate Cox proportional hazard models. Compared to the BMI group of 18.5-22.9 kg/m(2) , obese (BMI ≥ 30 kg/m(2) ) women were at an increased risk of developing overall cancer (hazard ratio = 1.36, 95% confidence interval = 1.21-1.52), postmenopausal breast cancer (HR: 2.43, 95% CI: 1.73-3.40), endometrial cancer (HR: 5.34, 95% CI: 3.48-8.18), liver cancer (HR: 1.93, 95% CI: 1.14-3.27) and epithelial ovarian cancer (HR: 2.44, 95% CI: 1.37-4.35). Weight gain during adulthood (per 5 kg gain) was associated with increased risk of all cancers combined (HR: 1.05, 95% CI: 1.03-1.08), postmenopausal breast cancer (HR: 1.17, 95% CI: 1.10-1.24) and endometrial cancer (HR: 1.37, 95% CI: 1.27-1.48). On the other hand, WHR was not associated with cancer risk after adjustment for baseline BMI. These findings suggest that obesity may be associated with cancer risk through different mechanisms from those for type 2 diabetes and CVD and support measures of maintaining health body weight to reduce cancer risk in Chinese women. © 2016 UICC.

  3. Geometric Algorithms for Trajectory Analysis

    NARCIS (Netherlands)

    Staals, Frank

    2015-01-01

    Technology such as the Global Positing System (GPS) has made tracking moving entities easy and cheap. As a result there is a large amount of trajectory data available, and an increasing demand on tools and techniques to analyze such data. We consider several analysis tasks for trajectory data, and d

  4. Organized Sport Trajectories from Childhood to Adolescence and Health Associations.

    Science.gov (United States)

    Howie, Erin K; McVeigh, Joanne A; Smith, Anne J; Straker, Leon M

    2016-07-01

    The purpose of this study was to identify unique organized sport trajectories from early childhood to late adolescence in an Australian pregnancy cohort, the Raine Study. Participation in organized sport was assessed at ages 5, 8, 10, 14, and 17 yr. Physical activity, body composition, and self-rated physical and mental health were assessed at the age of 20 yr. Latent class analysis was used to identify patterns of sport participation. To assess the internal validity of the trajectory classes, differences in health characteristics between trajectories were analyzed using generalized linear models. For girls, three trajectory classes were identified: consistent sport participators (47.5%), sport dropouts (34.3%), and sport nonparticipators (18.1%). For boys, three trajectory classes were identified: consistent sport participators (55.2%), sport dropouts (36.9%), and sport joiners (8.1%). For girls, there were overall differences across trajectory classes in lean body mass (P = 0.003), lean mass index (P = 0.06), and physical health (P = 0.004). For boys, there were differences across classes in physical activity (P = 0.018), percent body fat (P = 0.002), lean body mass (P health (P = 0.06), and depression scores (P = 0.27). This study identified unique, sex-specific trajectories of organized sport participation. The differences in health outcomes between trajectory classes, such as participants with consistent sport participation having more preferable health outcomes at the age of 20 yr, support the internal validity of the trajectories. Strategies are needed to identify and encourage those in the dropout trajectory to maintain their participation and those in the nonparticipator or joiner trajectories to join sport earlier. Specifically, interventions to encourage early sport participation in girls and help nonparticipating boys to join sport during adolescence may help more children receive the benefits of sport participation.

  5. Quantum trajectory pictures of laser cooling

    NARCIS (Netherlands)

    Nienhuis, G.; Kloe, J. de; Straten, P. van der

    1997-01-01

    We have applied the method of single atom trajectories to study the mechanism behind some cooling schemes in laser cooling. In several cases we recognize the cooling mechanism as being due to a "Sisyphus" process, where the atoms move in a spatially varying light shift potential and are optically pu

  6. Developmental Trajectories of Early Communication Skills

    Science.gov (United States)

    Maatta, Sira; Laakso, Marja-Leena; Tolvanen, Asko; Ahonen, Timo; Aro, Tuija

    2012-01-01

    Purpose: This study focused on developmental trajectories of prelinguistic communication skills and their connections to later parent-reported language difficulties. Method: The participants represent a subset of a community-based sample of 508 children. Data include parent reports of prelinguistic communication skills at 12, 15, 18, and 21 months…

  7. Developmental Trajectories of Early Communication Skills

    Science.gov (United States)

    Maatta, Sira; Laakso, Marja-Leena; Tolvanen, Asko; Ahonen, Timo; Aro, Tuija

    2012-01-01

    Purpose: This study focused on developmental trajectories of prelinguistic communication skills and their connections to later parent-reported language difficulties. Method: The participants represent a subset of a community-based sample of 508 children. Data include parent reports of prelinguistic communication skills at 12, 15, 18, and 21 months…

  8. Quantum trajectory pictures of laser cooling

    NARCIS (Netherlands)

    Nienhuis, G.; Kloe, J. de; Straten, P. van der

    1997-01-01

    We have applied the method of single atom trajectories to study the mechanism behind some cooling schemes in laser cooling. In several cases we recognize the cooling mechanism as being due to a "Sisyphus" process, where the atoms move in a spatially varying light shift potential and are optically

  9. Automated Sensitivity Analysis of Interplanetary Trajectories for Optimal Mission Design

    Science.gov (United States)

    Knittel, Jeremy; Hughes, Kyle; Englander, Jacob; Sarli, Bruno

    2017-01-01

    This work describes a suite of Python tools known as the Python EMTG Automated Trade Study Application (PEATSA). PEATSA was written to automate the operation of trajectory optimization software, simplify the process of performing sensitivity analysis, and was ultimately found to out-perform a human trajectory designer in unexpected ways. These benefits will be discussed and demonstrated on sample mission designs.

  10. Teacher Performance Trajectories in High- and Lower-Poverty Schools

    Science.gov (United States)

    Xu, Zeyu; Özek, Umut; Hansen, Michael

    2015-01-01

    This study explores whether teacher performance trajectory over time differs by school-poverty settings. Focusing on elementary school mathematics teachers in North Carolina and Florida, we find no systematic relationship between school student poverty rates and teacher performance trajectories. In both high- (=60% free/reduced-price lunch [FRPL])…

  11. Teacher Performance Trajectories in High- and Lower-Poverty Schools

    Science.gov (United States)

    Xu, Zeyu; Özek, Umut; Hansen, Michael

    2015-01-01

    This study explores whether teacher performance trajectory over time differs by school-poverty settings. Focusing on elementary school mathematics teachers in North Carolina and Florida, we find no systematic relationship between school student poverty rates and teacher performance trajectories. In both high- (=60% free/reduced-price lunch [FRPL])…

  12. Alcohol Use Growth Trajectories in Young Adolescence: Pathways and Predictors

    Science.gov (United States)

    Shamblen, Stephen R.; Ringwalt, Chris L.; Clark, Heddy K.; Hanley, Sean M.

    2014-01-01

    New analytical tools have facilitated the exploration of the trajectories of alcohol use; however, there are a limited number of studies that explore early adolescence. A sample of 5,903 youths followed from sixth through eighth grade was used to (1) examine the trajectories of alcohol use and (2) determine the degree to which common correlates…

  13. Obesity status trajectory groups among elementary school children

    Science.gov (United States)

    Little is known about patterns in the transition from healthy weight to overweight or obesity during the elementary school years. This study examined whether there were distinct body mass index (BMI) trajectory groups among elementary school children, and predictors of trajectory group membership. T...

  14. ARBAT Flat Trajectory Study Report.

    Science.gov (United States)

    1981-09-15

    per secona. Tnis Aas a rii.nner azimutn rate than the ARSAT System han. Tnhis m-iane use of an increase in tnet number of pulses per, frame not...position. The ARSAT radar system, in the present conficuration shall be exercised to achieve the intercept and track of the above targets. At the end of

  15. Posterior lumbar interbody fusion with cortical bone trajectory screw fixation versus posterior lumbar interbody fusion using traditional pedicle screw fixation for degenerative lumbar spondylolisthesis: a comparative study.

    Science.gov (United States)

    Sakaura, Hironobu; Miwa, Toshitada; Yamashita, Tomoya; Kuroda, Yusuke; Ohwada, Tetsuo

    2016-11-01

    OBJECTIVE Several biomechanical studies have demonstrated the favorable mechanical properties of the cortical bone trajectory (CBT) screw. However, no reports have examined surgical outcomes of posterior lumbar interbody fusion (PLIF) with CBT screw fixation for degenerative spondylolisthesis (DS) compared with those after PLIF using traditional pedicle screw (PS) fixation. The purposes of this study were thus to elucidate surgical outcomes after PLIF with CBT screw fixation for DS and to compare these results with those after PLIF using traditional PS fixation. METHODS Ninety-five consecutive patients underwent PLIF with CBT screw fixation for DS (CBT group; mean followup 35 months). A historical control group consisted of 82 consecutive patients who underwent PLIF with traditional PS fixation (PS group; mean follow-up 40 months). Clinical status was assessed using the Japanese Orthopaedic Association (JOA) scale score. Fusion status was assessed by dynamic plain radiographs and CT. The need for additional surgery and surgery-related complications was also evaluated. RESULTS The mean JOA score improved significantly from 13.7 points before surgery to 23.3 points at the latest follow-up in the CBT group (mean recovery rate 64.4%), compared with 14.4 points preoperatively to 22.7 points at final follow-up in the PS group (mean recovery rate 55.8%; p fusion was achieved in 84 patients from the CBT group (88.4%) and in 79 patients from the PS group (96.3%, p > 0.05). Symptomatic adjacent-segment disease developed in 3 patients from the CBT group (3.2%) compared with 9 patients from the PS group (11.0%, p fusion rate tended to be lower in the CBT group than in the PS group, although the difference was not statistically significant between the 2 groups.

  16. Fetal growth trajectories in pregnancies of European and South Asian mothers with and without gestational diabetes, a population-based cohort study

    Science.gov (United States)

    Jenum, Anne Karen; Yajnik, Chittaranjan S.; Mørkrid, Kjersti; Nakstad, Britt; Rognerud-Jensen, Odd Harald; Birkeland, Kåre I.; Vangen, Siri

    2017-01-01

    Objective Our aim was to examine the impact of gestational diabetes (GDM), from before the GDM-diagnosis is made, on fetal growth trajectories, and to compare it in Europeans and South Asians; two ethnic groups with dissimilar fetal growth patterns. Methods We studied European (n = 349) and South Asian (n = 184) pregnant women, from the population-based STORK-Groruddalen cohort in Oslo, Norway. Mothers were enrolled in early pregnancy, screened for GDM in gestational week 28 ±2, and classified as “non-GDM”, “mild GDM” or “moderate/severe GDM”. We measured fetal head circumference, abdominal circumference and femur length by ultrasound, and estimated fetal weight in gestational week 24, 32 and 37, and performed corresponding measurements at birth. Results In non-GDM pregnancies, South Asian fetuses (n = 156) had a slower growth from gestational week 24, compared with Europeans (n = 310). More than two thirds of the European mothers later diagnosed with GDM were overweight or obese in early pregnancy, while this was not observed in South Asians. Fetuses of GDM mothers tended to be smaller than fetuses of non-GDM mothers in week 24, but thereafter grew faster until birth. This pattern was especially pronounced in fetuses of South Asian mothers with moderate/severe GDM. In week 24 these fetuses had a -0.95 SD (95% CI: -1.53, -0.36) lower estimated fetal weight than their non-GDM counterparts. In contrast, at birth they were 0.45 SD (0.09, 0.81) larger. Conclusions Offspring of GDM mothers were smaller in mid pregnancy, but subsequently grew faster until birth, compared with offspring of non-GDM mothers. This pattern was most prominent in South Asian mothers with moderate to severe GDM. However, the most remarkable characteristic of these fetuses was not a large size at birth, but the small size in mid pregnancy, before the GDM diagnosis was set. PMID:28253366

  17. Trajectory Design to Benefit Trajectory-Based Surface Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trajectory-based operations constitute a key mechanism considered by the Joint Planning and Development Office (JPDO) for managing traffic in high-density or...

  18. Trajectory Design to Benefit Trajectory-Based Surface Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trajectory-based operations constitute a key mechanism considered by the Joint Planning and Development Office (JPDO) for managing traffic in high-density or...

  19. Fractional trajectories: Decorrelation versus friction

    Science.gov (United States)

    Svenkeson, A.; Beig, M. T.; Turalska, M.; West, B. J.; Grigolini, P.

    2013-11-01

    The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation of a fractional trajectory, that being an average over an ensemble of stochastic trajectories. Heretofore what has been interpreted as intrinsic friction, a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. We apply the general theory developed herein to the Lotka-Volterra ecological model, providing new insight into the final equilibrium state. The relaxation time to achieve this state is also considered.

  20. Attitude and Trajectory Estimation Using Earth Magnetic Field Data

    Science.gov (United States)

    Deutschmann, Julie; Bar-Itzhack, Itzhack Y.

    1996-01-01

    The magnetometer has long been a reliable, inexpensive sensor used in spacecraft momentum management and attitude estimation. Recent studies show an increased accuracy potential for magnetometer-only attitude estimation systems. Since the Earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computer and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both the spacecraft trajectory and attitude errors. Therefore, these errors can be used to estimate both trajectory and attitude. Traditionally, satellite attitude and trajectory have been estimated with completely separate system, using different measurement data. Recently, trajectory estimation for low earth orbit satellites was successfully demonstrated in ground software using only magnetometer data. This work proposes a single augmented extended Kalman Filter to simultaneously and autonomously estimate both spacecraft trajectory and attitude with data from a magnetometer and either dynamically determined rates or gyro-measured body rates.

  1. Trajectory Generation Method with Convolution Operation on Velocity Profile

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon [Hanyang Univ., Seoul (Korea, Republic of); Kim, Doik [Korea Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-03-15

    The use of robots is no longer limited to the field of industrial robots and is now expanding into the fields of service and medical robots. In this light, a trajectory generation method that can respond instantaneously to the external environment is strongly required. Toward this end, this study proposes a method that enables a robot to change its trajectory in real-time using a convolution operation. The proposed method generates a trajectory in real time and satisfies the physical limits of the robot system such as acceleration and velocity limit. Moreover, a new way to improve the previous method, which generates inefficient trajectories in some cases owing to the characteristics of the trapezoidal shape of trajectories, is proposed by introducing a triangle shape. The validity and effectiveness of the proposed method is shown through a numerical simulation and a comparison with the previous convolution method.

  2. Long-term effect of galantamine on cognitive function in patients with Alzheimer’s disease versus a simulated disease trajectory: an observational study in the clinical setting

    Directory of Open Access Journals (Sweden)

    Nakagawa R

    2017-04-01

    Full Text Available Ryoko Nakagawa,1 Takashi Ohnishi,1 Hisanori Kobayashi,1 Toshio Yamaoka,2 Tsutomu Yajima,3 Ai Tanimura,4 Toshiya Kato,4 Kazutake Yoshizawa1 1Evidence Generation Department, Medical Affairs Division, 2Clinical Data Management Department, R&D Division, 3Biostatistics Department, Quantitative Science Division, 4Drug Surveillance Department, R&D Division, Janssen Pharmaceutical K.K., Tokyo, Japan Background: Long-term maintenance of cognitive function is an important goal of treatment for Alzheimer’s disease (AD, but evidence about the long-term efficacy of cholinesterase inhibitors is sparse. To evaluate the long-term efficacy and safety of galantamine for AD in routine clinical practice, we conducted a 72-week post-marketing surveillance study. The effect of galantamine on cognitive function was estimated in comparison with a simulated disease trajectory. Patients and methods: Patients with mild-to-moderate AD received flexible dosing of galantamine (16–24 mg/day during this study. Cognitive function was assessed by the mini mental state examination (MMSE and the clinical status was determined by the Clinical Global Impression-Improvement (CGI-I. Changes of the MMSE score without treatment were estimated in each patient using Mendiondo’s model. Generalized linear mixed model analysis was performed to compare the simulated MMSE scores with the actual scores. Results: Of the 661 patients who were enrolled, 642 were evaluable for safety and 554 were assessed for efficacy. The discontinuation rate was 46.73%. Cognitive decline indicated by the mean change of actual MMSE scores was significantly smaller than the simulated decline. Individual analysis demonstrated that >70% of patients had better actual MMSE scores than their simulated scores. Significant improvement of CGI-I was also observed during the observation period. Adverse events occurred in 28.5% of patients and were serious in 8.41%. The reported events generally corresponded with the

  3. Adaptive Trajectory Design (ATD) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mission design within unstable/stable regions needs unification of individual trajectories from different dynamical regimes. NASA needs an automated process to blend...

  4. US Decadal Survey Outer Solar System Missions: Trajectory Options

    Science.gov (United States)

    Spilker, T. R.; Atkinson, D. H.; Strange, N. J.; Landau, D.

    2012-04-01

    The report of the US Planetary Science Decadal Survey (PSDS), released in draft form March 7, 2011, identifies several mission concepts involving travel to high-priority outer solar system (OSS) destinations. These include missions to Europa and Jupiter, Saturn and two of its satellites, and Uranus. Because travel to the OSS involves much larger distances and larger excursions out of the sun's gravitational potential well than inner solar system (ISS) missions, transfer trajectories for OSS missions are stronger drivers of mission schedule and resource requirements than for ISS missions. Various characteristics of each planet system, such as obliquity, radiation belts, rings, deep gravity wells, etc., carry ramifications for approach trajectories or trajectories within the systems. The maturity of trajectory studies for each of these destinations varies significantly. Europa has been the focus of studies for well over a decade. Transfer trajectory options from Earth to Jupiter are well understood. Current studies focus on trajectories within the Jovian system that could reduce the total mission cost of a Europa orbiter mission. Three missions to the Saturn system received high priority ratings in the PSDS report: two flagship orbital missions, one to Titan and one to Enceladus, and a Saturn atmospheric entry probe mission for NASA's New Frontiers Program. The Titan Saturn System Mission (TSSM) studies of 2007-2009 advanced our understanding of trajectory options for transfers to Saturn, including solar electric propulsion (SEP) trajectories. But SEP trajectories depend more on details of spacecraft and propulsion system characteristics than chemical trajectories, and the maturity of SEP trajectory search tools has not yet caught up with chemical trajectory tools, so there is still more useful research to be done on Saturn transfers. The TSSM studies revealed much about Saturn-orbiting trajectories that yield efficient and timely delivery to Titan or Enceladus

  5. Parental smoking exposure and adolescent smoking trajectories.

    Science.gov (United States)

    Mays, Darren; Gilman, Stephen E; Rende, Richard; Luta, George; Tercyak, Kenneth P; Niaura, Raymond S

    2014-06-01

    In a multigenerational study of smoking risk, the objective was to investigate the intergenerational transmission of smoking by examining if exposure to parental smoking and nicotine dependence predicts prospective smoking trajectories among adolescent offspring. Adolescents (n = 406) ages 12 to 17 and a parent completed baseline interviews (2001-2004), and adolescents completed up to 2 follow-up interviews 1 and 5 years later. Baseline interviews gathered detailed information on parental smoking history, including timing and duration, current smoking, and nicotine dependence. Adolescent smoking and nicotine dependence were assessed at each time point. Latent Class Growth Analysis identified prospective smoking trajectory classes from adolescence into young adulthood. Logistic regression was used to examine relationships between parental smoking and adolescent smoking trajectories. Four adolescent smoking trajectory classes were identified: early regular smokers (6%), early experimenters (23%), late experimenters (41%), and nonsmokers (30%). Adolescents with parents who were nicotine-dependent smokers at baseline were more likely to be early regular smokers (odds ratio 1.18, 95% confidence interval 1.05-1.33) and early experimenters (odds ratio 1.04, 95% confidence interval 1.04-1.25) with each additional year of previous exposure to parental smoking. Parents' current non-nicotine-dependent and former smoking were not associated with adolescent smoking trajectories. Exposure to parental nicotine dependence is a critical factor influencing intergenerational transmission of smoking. Adolescents with nicotine-dependent parents are susceptible to more intense smoking patterns and this risk increases with longer duration of exposure. Research is needed to optimize interventions to help nicotine-dependent parents quit smoking early in their children's lifetime to reduce these risks. Copyright © 2014 by the American Academy of Pediatrics.

  6. Pilot study on quantitative assessment of muscle imbalance: differences of muscle synergies, equilibrium-point trajectories, and endpoint stiffness in normal and pathological upper-limb movements.

    Science.gov (United States)

    Oku, Takanori; Uno, Kanna; Nishi, Tomoki; Kageyama, Masayuki; Phatiwuttipat, Pipatthana; Koba, Keitaro; Yamashita, Yuto; Murakami, Kenta; Uemura, Mitsunori; Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki

    2014-01-01

    This paper proposes a novel method for assessment of muscle imbalance based on muscle synergy hypothesis and equilibrium point (EP) hypothesis of motor control. We explain in detail the method for extracting muscle synergies under the concept of agonist-antagonist (AA) muscle pairs and for estimating EP trajectories and endpoint stiffness of human upper limbs in a horizontal plane using an electromyogram. The results of applying this method to the reaching movement of one normal subject and one hemiplegic subject suggest that (1) muscle synergies (the balance among coactivation of AA muscle pairs), particularly the synergies that contributes to the angular directional kinematics of EP and the limb stiffness, are quite different between the normal subject and the hemiplegic subject; (2) the concomitant EP trajectory is also different between the normal and hemiplegic subjects, corresponding to the difference of muscle synergies; and (3) the endpoint (hand) stiffness ellipse of the hemiplegic subject becomes more elongated and orientation of the major axis rotates clockwise more than that of the normal subject. The level of motor impairment would be expected to be assessed from a comparison of these differences of muscle synergies, EP trajectories, and endpoint stiffness among normal and pathological subjects using the method.

  7. The level and time course of disability: Trajectories of disability in adults and young elderly

    NARCIS (Netherlands)

    W.J. Nusselder (Wilma); C.W.N. Looman (Caspar); J.P. Mackenbach (Johan)

    2006-01-01

    textabstractObjectives. The objectives of this study were: (i) to identify trajectories in the level and time course of disability, (ii) to determine the relative frequency of each trajectory, and (iii) to assess the relationship of these trajectories with age, sex and the presence of four chronic

  8. Trayectorias con ruta predefinida en una bodega de datos: un caso de estudio sobre transporte público Trajectory with predefined path on a data warehouse: a case study on public transport

    Directory of Open Access Journals (Sweden)

    Francisco Javier Moreno Arboleda

    2010-01-01

    Full Text Available Hoy, gracias a los sistemas de posicionamiento global y dispositivos móviles equipados con sensores se puede capturar información acerca de la trayectoria seguida por objetos móviles tales como personas, animales, vehículos, entre otros. En este artículo se examinan en particular las trayectorias seguidas por objetos móviles en una ruta predefinida, por ejemplo un sistema de transporte público en el que los vehículos deben recorrer una ruta preestablecida. Se presenta un caso de estudio donde este tipo de trayectorias se incorporan como un sujeto de análisis en una bodega de datos.Today, thanks to global positioning systems and mobile devices equipped with sensors, it is possible to capture information about the trajectory followed by moving objects such as persons, animals, and vehicles, among others. In this paper we analyze, in particular, the trajectories followed by moving objects on a predefined route, as in the case of a public transport system, in which vehicles should travel by a predetermined route. We present a case study where this type of trajectories are incorporated as a subject of analysis in a data warehouse.

  9. Designing Complex Interplanetary Trajectories for the Global Trajectory Optimization Competitions

    CERN Document Server

    Izzo, Dario; Simões, Luís F; Märtens, Marcus

    2015-01-01

    The design of interplanetary trajectories often involves a preliminary search for options that are later refined into one final selected trajectory. It is this broad search that, often being intractable, inspires the international event called Global Trajectory Optimization Competition. In the first part of this chapter, we introduce some fundamental problems of space flight mechanics, building blocks of any attempt to participate successfully in these competitions and we describe the use of the open source software PyKEP to assemble them into a final global solution strategy. In the second part, we formulate an instance of a multiple asteroid rendezvous problem, related to the 7th edition of the competition, and we show step by step how to build a possible solution strategy. We introduce two new techniques useful in the design of this particular mission type: the use of an asteroid phasing value and its surrogates and the efficient computation of asteroid clusters. We show how basic building blocks, sided to...

  10. Foot trajectory approximation using the pendulum model of walking.

    Science.gov (United States)

    Fang, Juan; Vuckovic, Aleksandra; Galen, Sujay; Conway, Bernard A; Hunt, Kenneth J

    2014-01-01

    Generating a natural foot trajectory is an important objective in robotic systems for rehabilitation of walking. Human walking has pendular properties, so the pendulum model of walking has been used in bipedal robots which produce rhythmic gait patterns. Whether natural foot trajectories can be produced by the pendulum model needs to be addressed as a first step towards applying the pendulum concept in gait orthosis design. This study investigated circle approximation of the foot trajectories, with focus on the geometry of the pendulum model of walking. Three able-bodied subjects walked overground at various speeds, and foot trajectories relative to the hip were analysed. Four circle approximation approaches were developed, and best-fit circle algorithms were derived to fit the trajectories of the ankle, heel and toe. The study confirmed that the ankle and heel trajectories during stance and the toe trajectory in both the stance and the swing phases during walking at various speeds could be well modelled by a rigid pendulum. All the pendulum models were centred around the hip with pendular lengths approximately equal to the segment distances from the hip. This observation provides a new approach for using the pendulum model of walking in gait orthosis design.

  11. Job satisfaction developmental trajectories and health: A life course perspective.

    Science.gov (United States)

    Dirlam, Jonathan; Zheng, Hui

    2017-04-01

    Understanding the health consequence of job dissatisfaction becomes increasingly important because job insecurity, stress and dissatisfaction have significantly increased in the United States in the last decade. Despite the extensive work in this area, prior studies nonetheless may underestimate the harmful effect of job dissatisfaction due to the cross-sectional nature of their data and sample selection bias. This study applies a life-course approach to more comprehensively examine the relationship between job satisfaction and health. Using data from the NLSY 1979 cohort, we estimate group based job satisfaction trajectories of respondents starting at age 25 and ending at age 39. Four job satisfaction trajectory groups are identified, a consistently high satisfaction group, a downward group, an upward group, and a lowest satisfaction group. We examine the effects of these trajectories on several physical and mental health outcomes of respondents in their early forties. We find membership in the lowest job satisfaction trajectory group to be negatively associated with all five mental health outcomes, supporting the accumulation of risks life course model. Those in the upward job satisfaction trajectory group have similar health outcomes to those in the high job satisfaction trajectory group, supporting the social mobility life course model. Overall, we find the relationship between job satisfaction trajectories and health to be stronger for mental health compared to physical health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Trajectory Calculation as Forecasting Support Tool for Dust Storms

    Directory of Open Access Journals (Sweden)

    Sultan Al-Yahyai

    2014-01-01

    Full Text Available In arid and semiarid regions, dust storms are common during windy seasons. Strong wind can blow loose sand from the dry surface. The rising sand and dust is then transported to other places depending on the wind conditions (speed and direction at different levels of the atmosphere. Considering dust as a moving object in space and time, trajectory calculation then can be used to determine the path it will follow. Trajectory calculation is used as a forecast supporting tool for both operational and research activities. Predefined dust sources can be identified and the trajectories can be precalculated from the Numerical Weather Prediction (NWP forecast. In case of long distance transported dust, the tool should allow the operational forecaster to perform online trajectory calculation. This paper presents a case study for using trajectory calculation based on NWP models as a forecast supporting tool in Oman Meteorological Service during some dust storm events. Case study validation results showed a good agreement between the calculated trajectories and the real transport path of the dust storms and hence trajectory calculation can be used at operational centers for warning purposes.

  13. Effect of flapping trajectories on the dragonfly aerodynamics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of translational, figure-eight and double-figure-eight flapping trajectories on the dragonfly aerodynamics were numerically studied by solving the Navier-Stokes equations. There is a common characteristic regarding the lift/drag force coefficients that the downstroke flapping provides the lift forces while the upstroke flapping creates the thrust forces for different flapping trajectories. The maximum lift force coefficient exceeds five for the translational trajectory. It is greater than six for the figure-eight and double-figure-eight flapping trajectories, which is sufficiently larger than unity under the steady state flight condition. The ellipse and double-figure-eight flapping trajectories yield the decrease of the lift force, while the figure-eight flapping trajectory yields higher lift force as well as the thrust force than the translational flapping one. During the insect flight, the wing flapping status should be changed instantaneously to satisfy various requirements. Study of the flapping trajectories on the insect aerodynamics is helpful for the design of the Micro-air-vehicles (MAVs).

  14. Complexity of trajectories in rectangular billiards

    CERN Document Server

    Baryshnikov, Yu

    1994-01-01

    To a trajectory of a billiard in a parallelogram we assign its symbolic trajectory --- the sequence of numbers of coordinate planes, to which the faces met by the trajectory are parallel. The complexity of the trajectory is the number of different words of length n occurring in it. We prove that for generic trajectories the complexity is well defined and calculate it, confirming the conjecture of Arnoux, Mauduit, Shiokawa and Tamura[AMST].

  15. Complexity of trajectories in rectangular billiards

    Science.gov (United States)

    Baryshnikov, Yu.

    1995-11-01

    To a trajectory of the billiard in a cube we assign its symbolic trajectory-the sequence of numbers of coordinate planes, to which the faces met by the trajectory are parallel. The complexity of the trajectory is the number of different words of lengthn occurring in it. We prove that for generic trajectories the complexity is well defined and calculate it, confirming the conjecture of Arnoux, Mauduit, Shiokawa and Tamura [AMST].

  16. Generic trajectory representation and trajectory following for wheeled robots

    DEFF Research Database (Denmark)

    Kjærgaard, Morten; Andersen, Nils Axel; Ravn, Ole

    2014-01-01

    This article presents the work towards a purely generic navigation solution for wheeled mobile robots motivated by the following goals: Generic: Works for different types of robots. Configurable: Parameters maps to geometric properties of the robot. Predictable: Well defined where the robot...... will drive. Safe: Avoid fatal collisions. Based on a survey of existing methods and algorithms the article presents a generic way to represent constraints for different types of robots, a generic way to represent trajectories using Bëzier curves, a method to convert the trajectory so it can be driven...

  17. Energy dependence of the rho-trajectory intercept

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, A.; Canal, C.A.G.; Masperi, L.

    1978-02-01

    The forward ..pi..N charge-exchange differential cross section is studied in the framework of a recent model for the rho trajectory. Negative result shed doubts on the proposed nondiffractive renormalization mechanism for secondary Reggeons.

  18. Trajectories of Marital Conflict across the Life Course: Predictors and Interactions with Marital Happiness Trajectories

    Science.gov (United States)

    Kamp Dush, Claire M.; Taylor, Miles G.

    2012-01-01

    Using typologies outlined by Gottman and Fitzpatrick as well as institutional and companionate models of marriage, the authors conducted a latent class analysis of marital conflict trajectories using 20 years of data from the Marital Instability Over the Life Course study. Respondents were in one of three groups: high, medium (around the mean), or…

  19. Trajectories for a Near Term Mission to the Interstellar Medium

    Science.gov (United States)

    Arora, Nitin; Strange, Nathan; Alkalai, Leon

    2015-01-01

    Trajectories for rapid access to the interstellar medium (ISM) with a Kuiper Belt Object (KBO) flyby, launching between 2022 and 2030, are described. An impulsive-patched-conic broad search algorithm combined with a local optimizer is used for the trajectory computations. Two classes of trajectories, (1) with a powered Jupiter flyby and (2) with a perihelion maneuver, are studied and compared. Planetary flybys combined with leveraging maneuvers reduce launch C3 requirements (by factor of 2 or more) and help satisfy mission-phasing constraints. Low launch C3 combined with leveraging and a perihelion maneuver is found to be enabling for a near-term potential mission to the ISM.

  20. Sensitivity in the trajectory of long-range -particle

    Indian Academy of Sciences (India)

    P V Kunhikrishnan; A Rajan Nambiar; K P Santhosh

    2012-09-01

    The factors influencing the trajectory of long-range -particle in the cold ternary fission of 252Cf are discussed. The trajectory of the -particle is studied by considering the influence of the force on the -particle due to Coulomb and proximity potentials and is found to have sensitive dependence on the initial position and initial energy of the -particle. The sensitivity to initial conditions signifies the presence of deterministic chaos which is characterized by Lyapunov exponent (LE). The LE is calculated using Wolf’s algorithm and found positive which implies that the objectives of trajectory calculations are restricted.

  1. Asthma trajectories in early childhood: identifying modifiable factors.

    Directory of Open Access Journals (Sweden)

    Lidia Panico

    Full Text Available BACKGROUND: There are conflicting views as to whether childhood wheezing represents several discreet entities or a single but variable disease. Classification has centered on phenotypes often derived using subjective criteria, small samples, and/or with little data for young children. This is particularly problematic as asthmatic features appear to be entrenched by age 6/7. In this paper we aim to: identify longitudinal trajectories of wheeze and other atopic symptoms in early childhood; characterize the resulting trajectories by the socio-economic background of children; and identify potentially modifiable processes in infancy correlated with these trajectories. DATA AND METHODS: The Millennium Cohort Study is a large, representative birth cohort of British children born in 2000-2002. Our analytical sample includes 11,632 children with data on key variables (wheeze in the last year; ever hay-fever and/or eczema reported by the main carers at age 3, 5 and 7 using a validated tool, the International Study of Asthma and Allergies in Childhood module. We employ longitudinal Latent Class Analysis, a clustering methodology which identifies classes underlying the observed population heterogeneity. RESULTS: Our model distinguished four latent trajectories: a trajectory with both low levels of wheeze and other atopic symptoms (54% of the sample; a trajectory with low levels of wheeze but high prevalence of other atopic symptoms (29%; a trajectory with high prevalence of both wheeze and other atopic symptoms (9%; and a trajectory with high levels of wheeze but low levels of other atopic symptoms (8%. These groups differed in terms of socio-economic markers and potential intervenable factors, including household damp and breastfeeding initiation. CONCLUSION: Using data-driven techniques, we derived four trajectories of asthmatic symptoms in early childhood in a large, population based sample. These groups differ in terms of their socio-economic profiles

  2. Prosocial Behavior: Long-Term Trajectories and Psychosocial Outcomes.

    Science.gov (United States)

    Flynn, Elinor; Ehrenreich, Samuel E; Beron, Kurt J; Underwood, Marion K

    2015-08-01

    This study investigated developmental trajectories for prosocial behavior for a sample followed from age 10 - 18 and examined possible adjustment outcomes associated with membership in different trajectory groups. Participants were 136 boys and 148 girls, their teachers, and their parents (19.4% African American, 2.4% Asian, 51.9% Caucasian, 19.5% Hispanic, and 5.8% other). Teachers rated children's prosocial behavior yearly in grades 4 - 12. At the end of the 12(th) grade year, teachers, parents, and participants reported externalizing behaviors and participants reported internalizing symptoms, narcissism, and features of borderline personality disorder. Results suggested that prosocial behavior remained stable from middle childhood through late adolescence. Group-based mixture modeling revealed three prosocial trajectory groups: low (18.7%), medium (52.8%), and high (29.6%). Membership in the high prosocial trajectory group predicted lower levels of externalizing behavior as compared to the low prosocial trajectory group, and for girls, lower levels of internalizing symptoms. Membership in the medium prosocial trajectory group also predicted being lower on externalizing behaviors. Membership in the high prosocial trajectory group predicted lower levels of borderline personality features for girls only.

  3. Dissipative quantum trajectories in complex space: Damped harmonic oscillator

    Science.gov (United States)

    Chou, Chia-Chun

    2016-10-01

    Dissipative quantum trajectories in complex space are investigated in the framework of the logarithmic nonlinear Schrödinger equation. The logarithmic nonlinear Schrödinger equation provides a phenomenological description for dissipative quantum systems. Substituting the wave function expressed in terms of the complex action into the complex-extended logarithmic nonlinear Schrödinger equation, we derive the complex quantum Hamilton-Jacobi equation including the dissipative potential. It is shown that dissipative quantum trajectories satisfy a quantum Newtonian equation of motion in complex space with a friction force. Exact dissipative complex quantum trajectories are analyzed for the wave and solitonlike solutions to the logarithmic nonlinear Schrödinger equation for the damped harmonic oscillator. These trajectories converge to the equilibrium position as time evolves. It is indicated that dissipative complex quantum trajectories for the wave and solitonlike solutions are identical to dissipative complex classical trajectories for the damped harmonic oscillator. This study develops a theoretical framework for dissipative quantum trajectories in complex space.

  4. Trajectory generation of space telerobots

    Science.gov (United States)

    Lumia, R.; Wavering, A. J.

    1989-01-01

    The purpose is to review a variety of trajectory generation techniques which may be applied to space telerobots and to identify problems which need to be addressed in future telerobot motion control systems. As a starting point for the development of motion generation systems for space telerobots, the operation and limitations of traditional path-oriented trajectory generation approaches are discussed. This discussion leads to a description of more advanced techniques which have been demonstrated in research laboratories, and their potential applicability to space telerobots. Examples of this work include systems that incorporate sensory-interactive motion capability and optimal motion planning. Additional considerations which need to be addressed for motion control of a space telerobot are described, such as redundancy resolution and the description and generation of constrained and multi-armed cooperative motions. A task decomposition module for a hierarchical telerobot control system which will serve as a testbed for trajectory generation approaches which address these issues is also discussed briefly.

  5. Trajectory Indexing Using Movement Constraints

    DEFF Research Database (Denmark)

    Pfoser, D.; Jensen, Christian Søndergaard

    2005-01-01

    With the proliferation of mobile computing, the ability to index efficiently the movements of mobile objects becomes important. Objects are typically seen as moving in two-dimensional (x,y) space, which means that their movements across time may be embedded in the three-dimensional (x,y,t) space...... is to reduce movements to occur in one spatial dimension. As a consequence, the movement occurs in two-dimensional (x,t) space. The advantages of considering such lower-dimensional trajectories are that the overall size of the data is reduced and that lower-dimensional data is to be indexed. Since off......-the-shelf database management systems typically do not offer higher-dimensional indexing, this reduction in dimensionality allows us to use existing DBMSes to store and index trajectories. Moreover, we argue that, given the right circumstances, indexing these dimensionality-reduced trajectories can be more efficient...

  6. School life and adolescents' self-esteem trajectories.

    Science.gov (United States)

    Morin, Alexandre J S; Maïano, Christophe; Marsh, Herbert W; Nagengast, Benjamin; Janosz, Michel

    2013-01-01

    This study investigates heterogeneity in adolescents' trajectories of global self-esteem (GSE) and the relations between these trajectories and facets of the interpersonal, organizational, and instructional components of students' school life. Methodologically, this study illustrates the use of growth mixture analyses, and how to obtain proper student-level effects when there are multiple schools, but not enough to support multilevel analyses. This study is based on a 4-year, six-measurement-point, follow-up of 1,008 adolescents (M(age) = 12.6 years, SD = 0.6 at Time 1.) The results show four latent classes presenting elevated, moderate, increasing, and low trajectories defined based on GSE levels and fluctuations. The results show that GSE becomes trait-like as it increases and that school life effects, moderated by gender, played an important role in predicting membership in these trajectories. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

  7. Pregnancy anxiety and prenatal cortisol trajectories.

    Science.gov (United States)

    Kane, Heidi S; Dunkel Schetter, Christine; Glynn, Laura M; Hobel, Calvin J; Sandman, Curt A

    2014-07-01

    Pregnancy anxiety is a potent predictor of adverse birth and infant outcomes. The goal of the current study was to examine one potential mechanism whereby these effects may occur by testing associations between pregnancy anxiety and maternal salivary cortisol on 4 occasions during pregnancy in a sample of 448 women. Higher mean levels of pregnancy anxiety over the course of pregnancy predicted steeper increases in cortisol trajectories compared to lower pregnancy anxiety. Significant differences between cortisol trajectories emerged between 30 and 31 weeks of gestation. Results remained significant when adjusted for state anxiety and perceived stress. Neither changes in pregnancy anxiety over gestation, nor pregnancy anxiety specific to only a particular time in pregnancy predicted cortisol. These findings provide support for one way in which pregnancy anxiety may influence maternal physiology and contribute to a growing literature on the complex biological pathways linking pregnancy anxiety to birth and infant outcomes. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Monotone viable trajectories for functional differential inclusions

    Science.gov (United States)

    Haddad, Georges

    This paper is a study on functional differential inclusions with memory which represent the multivalued version of retarded functional differential equations. The main result gives a necessary and sufficient equations. The main result gives a necessary and sufficient condition ensuring the existence of viable trajectories; that means trajectories remaining in a given nonempty closed convex set defined by given constraints the system must satisfy to be viable. Some motivations for this paper can be found in control theory where F( t, φ) = { f( t, φ, u)} uɛU is the set of possible velocities of the system at time t, depending on the past history represented by the function φ and on a control u ranging over a set U of controls. Other motivations can be found in planning procedures in microeconomics and in biological evolutions where problems with memory do effectively appear in a multivalued version. All these models require viability constraints represented by a closed convex set.

  9. Fractional Trajectories: Decorrelation Versus Friction

    Science.gov (United States)

    2013-07-27

    function, andmoving back to the time domain yields the fractional trajectory V(t) = Eα(Otα)V(0). (4) Note that the Mittag-Leffler function is defined...bxy) ∂ ∂x − (cy − δxy) ∂ ∂y , (35) with the vector V having the components x and y. The predictor– corrector integration method is adopted to solve...Using the predictor– corrector method with α = 1 we numerically integrate the system of differential equations to find the operational time trajectory

  10. Dynamic trajectory control of gliders

    CERN Document Server

    Dilão, Rui

    2013-01-01

    We propose a new dynamic control algorithm in order to direct the trajectory of a glider to a pre-assigned target point. The algorithms runs iteratively and the approach to the target point is self-correcting. The algorithm is applicable to any non-powered lift-enabled vehicle (glider) travelling in planetary atmospheres. As a proof of concept, we have applied the new algorithm to the command and control of the trajectory of the Space Shuttle during the Terminal Area Energy Management (TAEM) phase.

  11. Association between trajectories of statin adherence and subsequent cardiovascular events.

    Science.gov (United States)

    Franklin, Jessica M; Krumme, Alexis A; Tong, Angela Y; Shrank, William H; Matlin, Olga S; Brennan, Troyen A; Choudhry, Niteesh K

    2015-10-01

    Trajectory models have been shown to (1) identify groups of patients with similar patterns of medication filling behavior and (2) summarize the trajectory, the average adherence in each group over time. However, the association between adherence trajectories and clinical outcomes remains unclear. This study investigated the association between 12-month statin trajectories and subsequent cardiovascular events. We identified patients with insurance coverage from a large national insurer who initiated a statin during January 1, 2007 to December 31, 2010. We assessed medication adherence during the 360 days following initiation and grouped patients based on the proportion of days covered (PDC) and trajectory models. We then measured cardiovascular events during the year after adherence assessment. Cox proportional hazards models were used to evaluate the association between adherence measures and cardiovascular outcomes; strength of association was quantified by the hazard ratio, the increase in model C-statistic, and the net reclassification index (NRI). Among 519 842 statin initiators, 8777 (1.7%) had a cardiovascular event during follow-up. More consistent medication use was associated with a lower likelihood of clinical events, whether adherence was measured through trajectory groups or PDC. When evaluating the prediction of future cardiovascular events by including a measure of adherence in the model, the best model reclassification was observed when adherence was measured using three or four trajectory groups (NRI = 0.189; 95% confidence interval: [0.171, 0.210]). Statin adherence trajectory predicted future cardiovascular events better than measures categorizing PDC. Thus, adherence trajectories may be useful for targeting adherence interventions. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Life Course Trajectories of Labour Market Participation among Young Adults Who Experienced Severe Alcohol-Related Health Outcomes: A Retrospective Cohort Study.

    Directory of Open Access Journals (Sweden)

    Tapio Paljärvi

    Full Text Available Long-term employment trajectories of young problem drinkers are poorly understood.We constructed retrospective labour market participation histories at ages 18-34 of 64 342 persons born in 1969-1982. Beginning from the year of each subject's 18th birthday, we extracted information from the records of Statistics Finland on educational attainment, main type of economic activity, months in employment, and months in unemployment for a minimum of seven years (range 7-16 years. We used information on the timing of alcohol-related hospitalizations and deaths in the same period to define problem drinkers with early onset limited course, early onset persistent course, and late onset problem drinking.Early onset limited course problem drinkers improved their employment considerably by age, whereas early onset persistent problem drinkers experienced a constant decline in their employment by age. From the age of 18 to 34, early onset persistent problem drinkers were in employment merely 12% of the time, in comparison with 39% among the early onset limited course problem drinkers, and 58% among the general population.These results indicate that young adults who were retrospectively defined as having early onset persistent course problem drinking were extensively marginalized from the labour market early on during their life course, and that their employment trajectory was significantly worse compared to other problem drinkers.

  13. A new symmetrical quasi-classical model for electronically non-adiabatic processes: Application to the case of weak non-adiabatic coupling

    Science.gov (United States)

    Cotton, Stephen J.; Miller, William H.

    2016-10-01

    Previous work has shown how a symmetrical quasi-classical (SQC) windowing procedure can be used to quantize the initial and final electronic degrees of freedom in the Meyer-Miller (MM) classical vibronic (i.e, nuclear + electronic) Hamiltonian, and that the approach provides a very good description of electronically non-adiabatic processes within a standard classical molecular dynamics framework for a number of benchmark problems. This paper explores application of the SQC/MM approach to the case of very weak non-adiabatic coupling between the electronic states, showing (as anticipated) how the standard SQC/MM approach used to date fails in this limit, and then devises a new SQC windowing scheme to deal with it. Application of this new SQC model to a variety of realistic benchmark systems shows that the new model not only treats the weak coupling case extremely well, but it is also seen to describe the "normal" regime (of electronic transition probabilities ≳ 0.1) even more accurately than the previous "standard" model.

  14. Academic trajectories of newcomer immigrant youth.

    Science.gov (United States)

    Suárez-Orozco, Carola; Gaytán, Francisco X; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

    2010-05-01

    Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve analysis revealed that although some newcomer students performed at high or improving levels over time, others showed diminishing performance. Multinomial logistic regressions identified significant group differences in academic trajectories, particularly between the high-achieving youth and the other groups. In keeping with ecological-developmental and stage-environment fit theories, School Characteristics (school segregation rate, school poverty rate, and student perceptions of school violence), Family Characteristics (maternal education, parental employment, and household structure), and Individual Characteristics (academic English proficiency, academic engagement, psychological symptoms, gender, and 2 age-related risk factors, number of school transitions and being overaged for grade placement) were associated with different trajectories of academic performance. A series of case studies triangulate many of the quantitative findings as well as illuminate patterns that were not detected in the quantitative data. Thus, the mixed-methods approach sheds light on the cumulative developmental challenges that immigrant students face as they adjust to their new educational settings.

  15. Depressive symptom trajectories in women affected by breast cancer and their male partners

    DEFF Research Database (Denmark)

    Rottmann, Nina; Hansen, Dorte Gilså; Hagedoorn, Mariët

    2016-01-01

    PURPOSE: The purpose of this study was to identify subgroups of breast cancer patients and their partners based on distinct trajectories of depressive symptoms, to examine how relationship quality and medical and sociodemographic factors were associated with these trajectories, and to explore...... whether patients and partners had similar trajectories. METHODS: A nationwide, population-based cohort of couples dealing with breast cancer was established in Denmark. Participants completed the Center for Epidemiologic Studies-Depression Scale at baseline and 5 and 12 months later. Sociodemographic...... and medical characteristics were retrieved from registers. A trajectory finite mixture model was used to identify trajectories. RESULTS: The trajectories of depressive symptoms over time were analyzed in 546 patients and 508 partners. Among patients, 13 % had a high stable trajectory, 38 % an intermediate...

  16. 船舶轨迹数据的Geodatabase管理方法%Study on Vessel Trajectories Database Manage System Based on Geodatabase

    Institute of Scientific and Technical Information of China (English)

    陈金海; 陆锋; 彭国均; 柯冉绚

    2012-01-01

    In order to monitor real-time vessel information to improve navigation safety, China's Maritime Safety Administration (MSA) has built the world's biggest Automatic Identification System (AIS) shore-based network, in which data such as ship position, name, purpose, course and speed are automatic collected 24 hours per day primarily in Chinese coastal waters. As a result, China is approaching the era of big data storage of vessel trajectories, which has brought great challenges to traditional moving objects data management systems. Beyond their basic functions of loading and displaying vessels' position records, an ideal vessel trajectories database should bring user more advance functions of analysis of ship tracking records by supporting spatio-temporal query and prediction of vessel movement. In this paper, we start with the character of vessel movement and abstract the data model of vessel trajectories according to state-of-the-art technology of moving objects databases. Due to the characteristics of vessel trajectories data, such as changing frequently, wide cover range and mass datum, it is argued that current methods of trajectories storage still deserve much more research and improvements, especially for spatio-temporal query and geoprocessing support methods. Considering the role of time perspective, vessel trajectories are managed by three kind of time unit (sampling instant, stepping period and 24 hours) so as to built a three-level organizational framework. By compressing the volume of data and matching original vessel tracking message into spatio-temporal cube unit the retrieval efficiency increases significantly. It was also described how to streamline the acquisition, loading, filtering, display and analysis of raw AIS log files. This method is applied in handling daily mass vessel tracking records which are covering western Taiwan Strait. Experiences show that this model satisfied the requirements of application. The storage is reduced and the

  17. Reversed graph embedding resolves complex single-cell trajectories.

    Science.gov (United States)

    Qiu, Xiaojie; Mao, Qi; Tang, Ying; Wang, Li; Chawla, Raghav; Pliner, Hannah A; Trapnell, Cole

    2017-10-01

    Single-cell trajectories can unveil how gene regulation governs cell fate decisions. However, learning the structure of complex trajectories with multiple branches remains a challenging computational problem. We present Monocle 2, an algorithm that uses reversed graph embedding to describe multiple fate decisions in a fully unsupervised manner. We applied Monocle 2 to two studies of blood development and found that mutations in the genes encoding key lineage transcription factors divert cells to alternative fates.

  18. Obesity status trajectory groups among elementary school children

    OpenAIRE

    Chen, Tzu-An; Baranowski, Tom; Jennette P. Moreno; O’Connor, Teresia M; Hughes, Sheryl O; Baranowski, Janice; Woehler, Deborah; Kimbro, Rachel T.; Johnston, Craig A.

    2016-01-01

    Background Little is known about patterns in the transition from healthy weight to overweight or obesity during the elementary school years. This study examined whether there were distinct body mass index (BMI) trajectory groups among elementary school children, and predictors of trajectory group membership. Methods This is a secondary analysis of 1651 elementary school children with complete biannual longitudinal data from kindergarten to the beginning of 5th grade. Heights and weights were ...

  19. Available Instruments for Analyzing Molecular Dynamics Trajectories.

    Science.gov (United States)

    Likhachev, I V; Balabaev, N K; Galzitskaya, O V

    2016-01-01

    Molecular dynamics trajectories are the result of molecular dynamics simulations. Trajectories are sequential snapshots of simulated molecular system which represents atomic coordinates at specific time periods. Based on the definition, in a text format trajectory files are characterized by their simplicity and uselessness. To obtain information from such files, special programs and information processing techniques are applied: from molecular dynamics animation to finding characteristics along the trajectory (versus time). In this review, we describe different programs for processing molecular dynamics trajectories. The performance of these programs, usefulness for analyses of molecular dynamics trajectories, strong and weak aspects are discussed.

  20. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  1. Canonical Transformations of Kepler Trajectories

    Science.gov (United States)

    Mostowski, Jan

    2010-01-01

    In this paper, canonical transformations generated by constants of motion in the case of the Kepler problem are discussed. It is shown that canonical transformations generated by angular momentum are rotations of the trajectory. Particular attention is paid to canonical transformations generated by the Runge-Lenz vector. It is shown that these…

  2. Privacy-Preserving Trajectory Collection

    DEFF Research Database (Denmark)

    Gidofalvi, Gyozo; Xuegang, Huang; Pedersen, Torben Bach

    2008-01-01

    . To remedy this situation, this paper first formally defines novel location privacy requirements. Then, it briefly presents a system for privacy--preserving trajectory collection that meets these requirements. The system is composed of an untrusted server and clients communicating in a P2P network. Location...

  3. Curved trajectories of actin-based motility in two dimensions

    Science.gov (United States)

    Wen, Fu-Lai; Leung, Kwan-tai; Chen, Hsuan-Yi

    2012-05-01

    Recent experiments have reported fascinating geometrical trajectories for actin-based motility of bacteria Listeria monocytogenes and functionalized beads. To understand the physical mechanism for these trajectories, we constructed a phenomenological model to study the motion of an actin-propelled disk in two dimensions. In our model, the force and actin density on the surface of the disk are influenced by the translation and rotation of the disk, which in turn is induced by the asymmetric distributions of those densities. We show that this feedback can destabilize a straight trajectory, leading to circular, S-shape and other geometrical trajectories observed in the experiments through bifurcations in the distributions of the force and actin density. The relation between our model and the models for self-propelled deformable particles is emphasized and discussed.

  4. Pneumatic motor speed control by trajectory tracking fuzzy logic controller

    Indian Academy of Sciences (India)

    Cengiz Safak; Vedat Topuz; A Fevzi Baba

    2010-02-01

    In this study, trajectory tracking fuzzy logic controller (TTFLC) is proposed for the speed control of a pneumatic motor (PM). A third order trajectory is defined to determine the trajectory function that has to be tracked by the PM speed. Genetic algorithm (GA) is used to find the TTFLC boundary values of membership functions (MF) and weights of control rules. In addition, artificial neural networks (ANN) modelled dynamic behaviour of PM is given. This ANN model is used to find the optimal TTFLC parameters by offline GA approach. The experimental results show that designed TTFLC successfully enables the PM speed track the given trajectory under various working conditions. The proposed approach is superior to PID controller. It also provides simple and easy design procedure for the PM speed control problem.

  5. Visual traffic jam analysis based on trajectory data.

    Science.gov (United States)

    Wang, Zuchao; Lu, Min; Yuan, Xiaoru; Zhang, Junping; van de Wetering, Huub

    2013-12-01

    In this work, we present an interactive system for visual analysis of urban traffic congestion based on GPS trajectories. For these trajectories we develop strategies to extract and derive traffic jam information. After cleaning the trajectories, they are matched to a road network. Subsequently, traffic speed on each road segment is computed and traffic jam events are automatically detected. Spatially and temporally related events are concatenated in, so-called, traffic jam propagation graphs. These graphs form a high-level description of a traffic jam and its propagation in time and space. Our system provides multiple views for visually exploring and analyzing the traffic condition of a large city as a whole, on the level of propagation graphs, and on road segment level. Case studies with 24 days of taxi GPS trajectories collected in Beijing demonstrate the effectiveness of our system.

  6. Student Learning-Game Designs: Emerging Learning Trajectories

    DEFF Research Database (Denmark)

    Weitze, Charlotte Lærke

    2016-01-01

    in four learning games created by students, to investigate how these elements were em83 ployed, to determine what learning trajectories emerged in the two digital game tools and to offer reflections and suggestions regarding the learning processes students experienced when building the various learning...... trajectories for specific learning goals into the digital games. The article examines how specific features in the two digital game tools, Scratch and RGBMaker, afford creation of learning trajectories in various ways, enabling deep learning and gameplay processes for the players of the games. According...... to the study, the level of complexity of the built‐in learning trajectories in the games was mirrored in the cognitive complexity of the student game designers' learning processes. The article presents four student‐created games that demonstrate a progression in the depth of potential learning experiences...

  7. Tracking Trajectory Planning of Space Manipulator for Capturing Operation

    Directory of Open Access Journals (Sweden)

    Panfeng Huang

    2008-11-01

    Full Text Available On-orbit rescuing uncontrolled spinning satellite (USS using space robot is a great challenge for future space service. This paper mainly present a trajectory planning method of space manipulator that can track, approach and catch the USS in free-floating situation. According to the motion characteristics of USS, we plan a spiral ascending trajectory for space manipulator to approach towards USS in Cartesian space. However, it is difficult to map this trajectory into the joint space and realize feasible motion in joint space because of dynamics singularities and dynamics couple of space robot system. Therefore, we utilize interval algorithm to handle these difficulties. The simulation study verifies that the spiral ascending trajectory can been realized. Moreover, the motion of manipulator is smooth and stable, the disturbance to the base is so limited that the attitude control can compensate it.

  8. Functional or fantasy? Examining the implications of subjective temporal perspective "trajectories" for life satisfaction.

    Science.gov (United States)

    Busseri, Michael A; Choma, Becky L; Sadava, Stan W

    2009-03-01

    In a 5-year longitudinal study of young community adults, the authors examined subjective temporal perspective (STP) "trajectories" derived from ratings of past, present, and anticipated future life satisfaction (LS) collected at two time points. Upward STP trajectories (past < present < future LS) were normative at both time points. Opposing hypotheses were derived from the literature concerning the potential positive versus negative implications of upward STP trajectories. Using latent trajectory modeling, individual differences in STP trajectories were examined in relation to mental, physical, and interpersonal functioning as well as future satisfaction bias (over- vs. underestimation of future LS). Steeper upward STP trajectories were associated with less positive functioning, both concurrently and prospectively, as well as greater future satisfaction bias. Therefore, rather than representing a realistic, adaptive form of self-enhancement, steep upward STP trajectories for LS appeared to be a form of fantasizing and wishful thinking, associated with distress, dissatisfaction, and dysfunction.

  9. Dynamic trajectory-based couch motion for improvement of radiation therapy trajectories in cranial SRT

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, R. Lee [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Thomas, Christopher G., E-mail: Chris.Thomas@cdha.nshealth.ca [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Medical Physics, Nova Scotia Cancer Centre, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia B3H 1V7 (Canada); Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Radiology, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada)

    2015-05-15

    Purpose: To investigate potential improvement in external beam stereotactic radiation therapy plan quality for cranial cases using an optimized dynamic gantry and patient support couch motion trajectory, which could minimize exposure to sensitive healthy tissue. Methods: Anonymized patient anatomy and treatment plans of cranial cancer patients were used to quantify the geometric overlap between planning target volumes and organs-at-risk (OARs) based on their two-dimensional projection from source to a plane at isocenter as a function of gantry and couch angle. Published dose constraints were then used as weighting factors for the OARs to generate a map of couch-gantry coordinate space, indicating degree of overlap at each point in space. A couch-gantry collision space was generated by direct measurement on a linear accelerator and couch using an anthropomorphic solid-water phantom. A dynamic, fully customizable algorithm was written to generate a navigable ideal trajectory for the patient specific couch-gantry space. The advanced algorithm can be used to balance the implementation of absolute minimum values of overlap with the clinical practicality of large-scale couch motion and delivery time. Optimized cranial cancer treatment trajectories were compared to conventional treatment trajectories. Results: Comparison of optimized treatment trajectories with conventional treatment trajectories indicated an average decrease in mean dose to the OARs of 19% and an average decrease in maximum dose to the OARs of 12%. Degradation was seen for homogeneity index (6.14% ± 0.67%–5.48% ± 0.76%) and conformation number (0.82 ± 0.02–0.79 ± 0.02), but neither was statistically significant. Removal of OAR constraints from volumetric modulated arc therapy optimization reveals that reduction in dose to OARs is almost exclusively due to the optimized trajectory and not the OAR constraints. Conclusions: The authors’ study indicated that simultaneous couch and gantry motion

  10. A Measure of Similarity Between Trajectories of Vessels

    Directory of Open Access Journals (Sweden)

    Le QI

    2016-03-01

    Full Text Available The measurement of similarity between trajectories of vessels is one of the kernel problems that must be addressed to promote the development of maritime intelligent traffic system (ITS. In this study, a new model of trajectory similarity measurement was established to improve the data processing efficiency in dynamic application and to reflect actual sailing behaviors of vessels. In this model, a feature point detection algorithm was proposed to extract feature points, reduce data storage space and save computational resources. A new synthesized distance algorithm was also created to measure the similarity between trajectories by using the extracted feature points. An experiment was conducted to measure the similarity between the real trajectories of vessels. The growth of these trajectories required measurements to be conducted under different voyages. The results show that the similarity measurement between the vessel trajectories is efficient and correct. Comparison of the synthesized distance with the sailing behaviors of vessels proves that results are consistent with actual situations. The experiment results demonstrate the promising application of the proposed model in studying vessel traffic and in supplying reliable data for the development of maritime ITS.

  11. Trajectory Synthesis for Fisher Information Maximization

    Science.gov (United States)

    Wilson, Andrew D.; Schultz, Jarvis A.; Murphey, Todd D.

    2015-01-01

    Estimation of model parameters in a dynamic system can be significantly improved with the choice of experimental trajectory. For general nonlinear dynamic systems, finding globally “best” trajectories is typically not feasible; however, given an initial estimate of the model parameters and an initial trajectory, we present a continuous-time optimization method that produces a locally optimal trajectory for parameter estimation in the presence of measurement noise. The optimization algorithm is formulated to find system trajectories that improve a norm on the Fisher information matrix (FIM). A double-pendulum cart apparatus is used to numerically and experimentally validate this technique. In simulation, the optimized trajectory increases the minimum eigenvalue of the FIM by three orders of magnitude, compared with the initial trajectory. Experimental results show that this optimized trajectory translates to an order-of-magnitude improvement in the parameter estimate error in practice. PMID:25598763

  12. The Trajectory Synthesizer Generalized Profile Interface

    Science.gov (United States)

    Lee, Alan G.; Bouyssounouse, Xavier; Murphy, James R.

    2010-01-01

    The Trajectory Synthesizer is a software program that generates aircraft predictions for Air Traffic Management decision support tools. The Trajectory Synthesizer being used by researchers at NASA Ames Research Center was restricted in the number of trajectory types that could be generated. This limitation was not sufficient to support the rapidly changing Air Traffic Management research requirements. The Generalized Profile Interface was developed to address this issue. It provides a flexible approach to describe the constraints applied to trajectory generation and may provide a method for interoperability between trajectory generators. It also supports the request and generation of new types of trajectory profiles not possible with the previous interface to the Trajectory Synthesizer. Other enhancements allow the Trajectory Synthesizer to meet the current and future needs of Air Traffic Management research.

  13. 基于市场轨道的创新路径研究--以苹果公司为例%The Study of Innovation Pathways Based on Market Trajectory:Evidence from Apple's Case

    Institute of Scientific and Technical Information of China (English)

    熊鸿儒; 吴贵生; 王毅

    2013-01-01

    Technological trajectory theory provides important implications for the choice of technological innova-tion pathways, but the diversity of innovation ways in practice shows great challenges to its traditional findings. This study explores to construct a new conceptual model, 'market trajectory', together with illustrating and analyz-ing its existence and application based on Apple Inc.'s case study. According to the dynamics of market needs evo-lution, the formation of 'market trajectory' is oriented by satisfying new demands and opening new markets. This model puts forward the traditional trajectory research and systematically summarizes the evolutionary pattern of de-mand-driven innovation activities and market opportunity exploitation, which shall extend the space of choosing in-novation pathways for firms.%  技术轨道理论为企业技术创新路径选择提供了重要启示,但实践中存在的“创新路径多样性”对其提出了挑战。构建了“市场轨道”概念模型,并通过美国苹果公司的创新案例研究论证和剖析了市场轨道的存在及其所对应的创新路径。基于市场需求的动态演化特性,以满足新需求、打开新市场为导向的创新路径是新“市场轨道”创立的结果。“市场轨道”概念模型拓展了技术轨道理论,总结了基于需求导向和利用市场机会进行创新的演化规律,可以丰富企业的创新路径选择空间。

  14. Employment Trajectories Beyond Retirement.

    Science.gov (United States)

    Burkert, Carola; Hochfellner, Daniela

    2017-01-01

    Within the political and academic debate on working longer, post-retirement employment is discussed as an alternative to maintain older workers in the labor market. Our article enhances this discussion by studying determinants of transitions into post-retirement jobs within differing work environments of birth cohorts 1940-1942. We estimate proportional subhazard models accounting for competing risks using unique German social security data linked to pension accounts. Our findings suggest that individuals' preferences to take up post-retirement jobs are not mutually exclusive. Our study provides evidence that taking up post-retirement jobs is related to seeking financial security, continuity, and work ability, suggesting that public policy has to develop target-oriented support through a public policy mix of different measures aligned to the different peer groups in the labor market.

  15. Gender Differences in Anxiety Trajectories from Middle to Late Adolescence.

    Science.gov (United States)

    Ohannessian, Christine McCauley; Milan, Stephanie; Vannucci, Anna

    2017-04-01

    Although developmental trajectories of anxiety symptomatology have begun to be explored, most research has focused on total anxiety symptom scores during childhood and early adolescence, using racially/ethnically homogenous samples. Understanding the heterogeneous courses of anxiety disorder symptoms during middle to late adolescence has the potential to clarify developmental risk models of anxiety and to inform prevention programs. Therefore, this study specifically examined gender differences in developmental trajectories of anxiety disorder symptoms (generalized anxiety disorder, panic disorder, and social anxiety disorder) from middle to late adolescence in a diverse community sample (N = 1000; 57 % female; 65 % White), assessed annually over 2 years. Latent growth curve modeling revealed that girls exhibited a slight linear decrease in generalized anxiety disorder, panic disorder, and social anxiety disorder symptoms, whereas boys exhibited a stable course. These models suggested that one trajectory was appropriate for panic disorder symptoms in both girls and boys. Growth mixture models indicated the presence of four latent generalized anxiety disorder symptom trajectory classes: low increasing, moderate decreasing slightly, high decreasing, and very high decreasing rapidly. Growth mixture models also suggested the presence of five latent social anxiety disorder symptom trajectory classes: a low stable trajectory class and four classes that were qualitatively similar to the latent generalized anxiety disorder trajectories. For both generalized anxiety disorder and social anxiety disorder symptoms, girls were significantly more likely than boys to be in trajectory classes characterized by moderate or high initial symptoms that subsequently decreased over time. These findings provide novel information regarding the developmental course of anxiety disorder symptoms in adolescents.

  16. Reaching affects saccade trajectories.

    Science.gov (United States)

    Tipper, S P; Howard, L A; Paul, M A

    2001-01-01

    The pre-motor theory suggests that, when attention is oriented to a location, the motor systems that are involved in achieving current behavioural goals are activated. For example, when a task requires accurate reaching, attention to a location activates the motor circuits controlling saccades and manual reaches. These actions involve separate neural systems for the control of eye and hand, but we believe that the selection processes acting on neural population codes within these systems are similar and can affect each other. The attentional effect can be revealed in the subsequent movement. The present study shows that the path the eye takes as it saccades to a target is affected by whether a reach to the target is also produced. This effect is interpreted as the influence of a hand-centred frame used in reaching on the spatial frame of reference required for the saccade.

  17. 自然风对旋转弹丸外弹道性能影响的仿真研究%Simulation and Study of Effect of Natural Wind on External Trajectory Performance of Spinning Projectile

    Institute of Scientific and Technical Information of China (English)

    冯德朝; 张方方; 胡春晓

    2012-01-01

    为研究自然风对旋转弹丸外弹道性能的影响,基于坐标变换理论考虑了地球曲率变化对刚体弹道模型的作用,分析了自然风对各气动力和气动力矩的影响,建立了非标准条件下的刚体外弹道模型.应用该模型对某105mm榴弹不同风速、风向下的外弹道过程进行仿真,结果表明,自然风对飞行弹丸的攻角姿态有较大影响,进而影响弹丸的射程和方向偏移量;自然风对弹丸攻角姿态的影响在弹丸飞行的初始阶段风速大小起主要作用,而在弹丸飞行的中间阶段则是风矢方向起主要作用.%To study the effect of natural wind on external trajectory performance of spinning projectile, effect of earth curvature was analyzed based on the theory of coordinate transformation, the effect of natural wind on aerodynamic force and moment was analyzed. The external trajectory model was established under nonstandard environment. The external trajectory of a 105mm shrapnel at different wind speeds and wind orientation was simulated by use of this model. The calculated results shows that the attack angle of projectile is crucially affected by natural wind which eventually changes the trajectory of projectile. The size of wind speed plays an important role in the effect of natural wind on the dynamical stability at the beginning stage of flying projectile, while at the midway stage the main factor is changed to the direction of wind.

  18. Minimal Exit Trajectories with Optimum Correctional Manoeuvres

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1980-10-01

    Full Text Available Minimal exit trajectories with optimum correctional manoeuvers to a rocket between two coplaner, noncoaxial elliptic orbits in an inverse square gravitational field have been investigated. Case of trajectories with no correctional manoeuvres has been analysed. In the end minimal exit trajectories through specified orbital terminals are discussed and problem of ref. (2 is derived as a particular case.

  19. Target selection and transfer trajectories design for exploring asteroid mission

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Technique of target selection and profiles of transfer trajectory for Chinese asteroid exploring mission are studied systemically.A complete set of approaches to selecting mission targets and designing the transfer trajectory is proposed.First,when selecting a target for mission,some factors regarded as the scientific motivations are discussed.Then,when analyzing the accessibility of targets,instead of the classical strategy,the multiple gravity-assist strategy is provided.The suitable and possible targets,taking into account scientific value and technically feasible,are obtained via selection and estimation.When designing the transfer trajectory for exploring asteroid mission,an approach to selecting gravity-assist celestial body is proposed.Finally,according to the mission constraints,the trajectory profile with 2-years △V-EGA for exploring asteroid is presented.Through analyzing the trajectory profile,unexpected result that the trajectory would pass by two main-belts asteroids is found.So,the original proposal is extended to the multiple flybys mission.It adds the scientific return for asteroid mission.

  20. Seasonal variations and sources study by way of back trajectories and ANOVA for ambient air pollutants (particulates and metallic elements) within a mixed area at Longjing, central Taiwan: 1-year observation.

    Science.gov (United States)

    Fang, Guor-Cheng; Lo, Chaur-Tsuen; Zhuang, Yuan-Jie; Cho, Meng-Hsien; Huang, Chao-Yang; Xiao, You-Fu; Tsai, Kai-Hsiang

    2017-02-01

    This study measured the concentrations of particulates and metallic elements in ambient air by using PS-1 sampler (TSP) at Longjing area. And this study focuses on the collection of ambient air particulates, metallic elements, particulate-bound mercury Hg(p), concentrations. In addition, the sources of ambient pollutants by way of back trajectory analysis are found. Moreover, test mean concentration variance differences for metallic elements (PM, Hg(p), Mn, Fe, Zn, Cr, Cu, and Pb) among the four seasons (spring, summer, autumn and winter) through ANOVA are calculated. The result indicates that the average highest particulate concentration occurred in winter season, and the order was winter > spring > autumn > summer, and the mostly highest average metallic element (Mn, Fe, Zn, Cr, Cu, Pb) concentrations occurred in autumn. Moreover, the mostly average lowest metallic element concentrations occurred in summer. In addition, the above results of backward trajectories that the major particulate pollutants parcel mainly come from northeastern Taiwan. Moreover, when comparing the results of the first half year to that of the second half year, the they indicated that all metallic elements displayed significant differences in concentrations except those of Hg(p), Mn, Fe, Zn. Finally, metallic element Hg(p) is the only one which showed no significant concentration difference from either seasonal variations or half-year observations.

  1. Trajectories of low back pain

    DEFF Research Database (Denmark)

    Axén, Iben; Leboeuf-Yde, Charlotte

    2013-01-01

    Low back pain is not a self-limiting problem, but rather a recurrent and sometimes persistent disorder. To understand the course over time, detailed investigation, preferably using repeated measurements over extended periods of time, is needed. New knowledge concerning short-term trajectories...... indicates that the low back pain 'episode' is short lived, at least in the primary care setting, with most patients improving. Nevertheless, in the long term, low back pain often runs a persistent course with around two-thirds of patients estimated to be in pain after 12 months. Some individuals never have...... low back pain, but most have it on and off or persistently. Thus, the low back pain 'condition' is usually a lifelong experience. However, subgroups of patients with different back pain trajectories have been identified and linked to clinical parameters. Further investigation is warranted...

  2. Trajectory Indexing Using Movement Constraints

    DEFF Research Database (Denmark)

    Pfoser, D.; Jensen, Christian Søndergaard

    2005-01-01

    With the proliferation of mobile computing, the ability to index efficiently the movements of mobile objects becomes important. Objects are typically seen as moving in two-dimensional (x,y) space, which means that their movements across time may be embedded in the three-dimensional (x,y,t) space....... Further, the movements are typically represented as trajectories, sequences of connected line segments. In certain cases, movement is restricted; specifically, in this paper, we aim at exploiting that movements occur in transportation networks to reduce the dimensionality of the data. Briefly, the idea...... is to reduce movements to occur in one spatial dimension. As a consequence, the movement occurs in two-dimensional (x,t) space. The advantages of considering such lower-dimensional trajectories are that the overall size of the data is reduced and that lower-dimensional data is to be indexed. Since off...

  3. Ray trajectories for Alcubierre spacetime

    CERN Document Server

    Anderson, Tom H; Lakhtakia, Akhlesh

    2011-01-01

    The Alcubierre spacetime was simulated by means of a Tamm medium which is asymptotically identical to vacuum and has constitutive parameters which are ontinuous functions of the spatial coordinates. Accordingly, the Tamm medium is amenable to physical realization as a nanostructured metamaterial. A comprehensive characterization of ray trajectories in the Tamm medium was undertaken, within the geometric-optics regime. Propagation directions corresponding to evanescent waves were identified: these occur in the region of the Tamm medium which corresponds to the warp bubble of the Alcubierre spacetime, especially for directions perpendicular to the velocity of the warp bubble at high speeds of that bubble. Ray trajectories are acutely sensitive to the magnitude and direction of the warp bubble's velocity, but rather less sensitive to the thickness of the transition zone between the warp bubble and its background. In particular, for rays which travel in the same direction as the warp bubble, the latter acts as a ...

  4. Quantum frictionless trajectories versus geodesics

    Science.gov (United States)

    Barbado, Luis C.; Barceló, Carlos; Garay, Luis J.

    2015-10-01

    Moving particles outside a star will generally experience quantum friction caused by the Unruh radiation reaction. There exist however radial trajectories that lack this effect (in the outgoing radiation sector, and ignoring backscattering). Along these trajectories, observers perceive just stellar emission, without further contribution from the Unruh effect. They turn out to have the property that the variations of the Doppler and the gravitational shifts compensate each other. They are not geodesics, and their proper acceleration obeys an inverse square law, which means that it could in principle be generated by outgoing stellar radiation. In the case of a black hole emitting Hawking radiation, this may lead to a buoyancy scenario. The ingoing radiation sector has little effect and seems to slow down the fall even further.

  5. Interference, reduced action, and trajectories

    OpenAIRE

    2006-01-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichroma...

  6. Childhood body mass index trajectories: modeling, characterizing, pairwise correlations and socio-demographic predictors of trajectory characteristics

    Directory of Open Access Journals (Sweden)

    Wen Xiaozhong

    2012-03-01

    Full Text Available Abstract Background Modeling childhood body mass index (BMI trajectories, versus estimating change in BMI between specific ages, may improve prediction of later body-size-related outcomes. Prior studies of BMI trajectories are limited by restricted age periods and insufficient use of trajectory information. Methods Among 3,289 children seen at 81,550 pediatric well-child visits from infancy to 18 years between 1980 and 2008, we fit individual BMI trajectories using mixed effect models with fractional polynomial functions. From each child's fitted trajectory, we estimated age and BMI at infancy peak and adiposity rebound, and velocity and area under curve between 1 week, infancy peak, adiposity rebound, and 18 years. Results Among boys, mean (SD ages at infancy BMI peak and adiposity rebound were 7.2 (0.9 and 49.2 (11.9 months, respectively. Among girls, mean (SD ages at infancy BMI peak and adiposity rebound were 7.4 (1.1 and 46.8 (11.0 months, respectively. Ages at infancy peak and adiposity rebound were weakly inversely correlated (r = -0.09. BMI at infancy peak and adiposity rebound were positively correlated (r = 0.76. Blacks had earlier adiposity rebound and greater velocity from adiposity rebound to 18 years of age than whites. Higher birth weight z-score predicted earlier adiposity rebound and higher BMI at infancy peak and adiposity rebound. BMI trajectories did not differ by birth year or type of health insurance, after adjusting for other socio-demographics and birth weight z-score. Conclusions Childhood BMI trajectory characteristics are informative in describing childhood body mass changes and can be estimated conveniently. Future research should evaluate associations of these novel BMI trajectory characteristics with adult outcomes.

  7. Perching aerodynamics and trajectory optimization

    Science.gov (United States)

    Wickenheiser, Adam; Garcia, Ephrahim

    2007-04-01

    Advances in smart materials, actuators, and control architecture have enabled new flight capabilities for aircraft. Perching is one such capability, described as a vertical landing maneuver using in-flight shape reconfiguration in lieu of high thrust generation. A morphing, perching aircraft design is presented that is capable of post stall flight and very slow landing on a vertical platform. A comprehensive model of the aircraft's aerodynamics, with special regard to nonlinear affects such as flow separation and dynamic stall, is discussed. Trajectory optimization using nonlinear programming techniques is employed to show the effects that morphing and nonlinear aerodynamics have on the maneuver. These effects are shown to decrease the initial height and distance required to initiate the maneuver, reduce the bounds on the trajectory, and decrease the required thrust for the maneuver. Perching trajectories comparing morphing versus fixed-configuration and stalled versus un-stalled aircraft are presented. It is demonstrated that a vertical landing is possible in the absence of high thrust if post-stall flight capabilities and vehicle reconfiguration are utilized.

  8. Bohmian trajectories of Airy packets

    Energy Technology Data Exchange (ETDEWEB)

    Nassar, Antonio B., E-mail: anassar@hw.com [Science Department, Harvard-Westlake School, 3700 Coldwater Canyon, Studio City, 91604 (United States); Department of Sciences, University of California, Los Angeles, Extension Program, 10995 Le Conte Avenue, Los Angeles, CA 90024 (United States); Miret-Artés, Salvador [Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid (Spain)

    2014-09-15

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space–time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject’s theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  9. Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections.

    Science.gov (United States)

    Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya; Sumpter, Bobby G

    2016-09-13

    The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; Nat. Commun. 2014, 5, 3180) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. The protonic and deuteronic wave functions for the H/D isotopologues of the hexyl side chains are described within a quantum trajectory/electronic structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wave functions; the classical forces are generated with a density functional tight binding method. The resulting protonic and deuteronic time-dependent wave functions are used to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. While the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wave functions may account for experimental trends by promoting charge transfer in P3HT:PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT:PCBM.

  10. Getting Bigger, Quicker? Gendered Socioeconomic Trajectories in Body Mass Index across the Adult Lifecourse: A Longitudinal Study of 21,403 Australians.

    Science.gov (United States)

    Feng, Xiaoqi; Wilson, Andrew

    2015-01-01

    Do socioeconomic inequities in body mass index (BMI) widen across the adult lifecourse? BMI data for 29,104 male and 32,454 female person-years aged 15 years and older (21,403 persons in total) were extracted from the Household, Income and Labour Dynamics in Australia between 2006 and 2012. Multilevel linear regression was used to examine age and gender specific trajectories in BMI by quintiles of neighborhood socioeconomic circumstance. Models were adjusted for probable sources of confounding, including couple status, number of children resident, if somebody in the household had been pregnant in the last 12 months, the highest level of education achieved, the average household gross income, and the percentage of time in the last year spent unemployed. Approximately 9.6% of BMI variation was observed between neighborhoods. High neighborhood disadvantage was associated with 2.09 kg/m2 heavier BMI (95%CI 1.82, 2.36). At age 15-24y, socioeconomic inequity in BMI was already evident among men and women especially (22.6 kg/m2 among women in the most affluent areas compared with 25.4 kg/m2 among the most disadvantaged). Among women only, the socioeconomic gap widened from 2.8 kg/m2 at age 15-24y to 3.2 kg/m2 by age 35-44y. Geographical factors may contribute to more rapid weight gain among women living in disadvantaged neighborhoods.

  11. The effect of zero-point energy differences on the isotope dependence of the formation of ozone: a classical trajectory study.

    Science.gov (United States)

    Schinke, Reinhard; Fleurat-Lessard, Paul

    2005-03-01

    The effect of zero-point energy differences (DeltaZPE) between the possible fragmentation channels of highly excited O(3) complexes on the isotope dependence of the formation of ozone is investigated by means of classical trajectory calculations and a strong-collision model. DeltaZPE is incorporated in the calculations in a phenomenological way by adjusting the potential energy surface in the product channels so that the correct exothermicities and endothermicities are matched. The model contains two parameters, the frequency of stabilizing collisions omega and an energy dependent parameter Delta(damp), which favors the lower energies in the Maxwell-Boltzmann distribution. The stabilization frequency is used to adjust the pressure dependence of the absolute formation rate while Delta(damp) is utilized to control its isotope dependence. The calculations for several isotope combinations of oxygen atoms show a clear dependence of relative formation rates on DeltaZPE. The results are similar to those of Gao and Marcus [J. Chem. Phys. 116, 137 (2002)] obtained within a statistical model. In particular, like in the statistical approach an ad hoc parameter eta approximately 1.14, which effectively reduces the formation rates of the symmetric ABA ozone molecules, has to be introduced in order to obtain good agreement with the measured relative rates of Janssen et al. [Phys. Chem. Chem. Phys. 3, 4718 (2001)]. The temperature dependence of the recombination rate is also addressed.

  12. Mobile Information Collectors' Trajectory Data Warehouse Design

    CERN Document Server

    oueslati, wided

    2010-01-01

    To analyze complex phenomena which involve moving objects, Trajectory Data Warehouse (TDW) seems to be an answer for many recent decision problems related to various professions (physicians, commercial representatives, transporters, ecologists ...) concerned with mobility. This work aims to make trajectories as a first class concept in the trajectory data conceptual model and to design a TDW, in which data resulting from mobile information collectors' trajectory are gathered. These data will be analyzed, according to trajectory characteristics, for decision making purposes, such as new products commercialization, new commerce implementation, etc.

  13. Trajectory Design Considerations for Exploration Mission 1

    Science.gov (United States)

    Dawn, Timothy F.; Gutkowski, Jeffrey P.; Batcha, Amelia L.

    2017-01-01

    Exploration Mission 1 (EM-1) will be the first mission to send an uncrewed Orion vehicle to cislunar space in 2018, targeted to a Distant Retrograde Orbit (DRO). Analysis of EM-1 DRO mission opportunities in 2018 help characterize mission parameters that are of interest to other subsystems (e.g., power, thermal, communications, flight operations, etc). Subsystems request mission design trades which include: landing lighting, addition of an Orion main engine checkout burn, and use of auxiliary thruster only cases. This paper examines the evolving trade studies that incorporate subsystem feedback and demonstrate the feasibility of these constrained mission trajectory designs and contingencies.

  14. CHANG'E-3 contingency scheme and trajectory

    Science.gov (United States)

    Liu, Lei; Cao, Jian-feng; Liu, Yong; Hu, Song-jie; Tang, Ge-shi; Xie, Jian-feng

    2015-02-01

    This paper addresses contingency trajectories of CHANG'E-3 in the case of a failure of the lunar brake, which is crucial to the CHANG'E-3 mission, i.e., the first Chinese lunar soft-landing and rover mission. Considering the flight-time and control-energy requirements placed on the contingency trajectories, the paper proposes a direct return method and a low-energy return method and develops the corresponding contingency trajectories based on the CHANG'E-3 cislunar transfer trajectory. The direct return method was studied on return style, flight time, control energy, and influence of maneuver time on energy. The low-energy return method was investigated using the method of invariant manifold calculations for a Lissajous orbit, the method of direct libration-point orbit transfer and injection, and the control strategy used for a low-energy trajectory. The results demonstrate that the control energy for direct return trajectories can be reduced using a certain flight course. When a flight time of less than half of a month is desired, a trajectory from the north celestial pole should be selected as a lunar approach trajectory for CHANG'E-3. Otherwise, a trajectory from the south celestial pole should be selected. Furthermore, these two trajectories have approximately equal velocity increments if their flight-time difference is close to half of a month. In the case of the low-energy return method, methods using approximate manifold calculations for a Lissajous orbit and the direct transfer and injection to a libration-point orbit are proposed and shown to be useful. CHANG'E-3 would return via the Sun-Earth L2 libration point and would require four maneuvers during its flight. The low-energy return method offers remarkable energy savings of up to 267 m/s compared to the direct return method. The methodology not only provides a contingency control technique for CHANG'E-3 and for future lunar missions, but it also serves as a beneficial supplement to the present studies

  15. Simulation Propulsion System and Trajectory Optimization

    Science.gov (United States)

    Hendricks, Eric S.; Falck, Robert D.; Gray, Justin S.

    2017-01-01

    A number of new aircraft concepts have recently been proposed which tightly couple the propulsion system design and operation with the overall vehicle design and performance characteristics. These concepts include propulsion technology such as boundary layer ingestion, hybrid electric propulsion systems, distributed propulsion systems and variable cycle engines. Initial studies examining these concepts have typically used a traditional decoupled approach to aircraft design where the aerodynamics and propulsion designs are done a-priori and tabular data is used to provide inexpensive look ups to the trajectory ana-ysis. However the cost of generating the tabular data begins to grow exponentially when newer aircraft concepts require consideration of additional operational parameters such as multiple throttle settings, angle-of-attack effects on the propulsion system, or propulsion throttle setting effects on aerodynamics. This paper proposes a new modeling approach that eliminated the need to generate tabular data, instead allowing an expensive propulsion or aerodynamic analysis to be directly integrated into the trajectory analysis model and the entire design problem optimized in a fully coupled manner. The new method is demonstrated by implementing a canonical optimal control problem, the F-4 minimum time-to-climb trajectory optimization using three relatively new analysis tools: Open M-DAO, PyCycle and Pointer. Pycycle and Pointer both provide analytic derivatives and Open MDAO enables the two tools to be combined into a coupled model that can be run in an efficient parallel manner that helps to cost the increased cost of the more expensive propulsion analysis. Results generated with this model serve as a validation of the tightly coupled design method and guide future studies to examine aircraft concepts with more complex operational dependencies for the aerodynamic and propulsion models.

  16. Quasi-Classical Trajectory Calculations of Isotopic Effect on Reactions H (D, T) + OCl%准经典轨线计算同位素对反应H+Ocl的影响

    Institute of Scientific and Technical Information of China (English)

    韩成利; 李亚民

    2014-01-01

    用准经典轨线的方法计算了反应H(D,T)+OCl,主要是研究同位素效应对反应截面、产物的转动取向和分支比的影响.准经典轨线的计算选择了PSB2势能面,在0.2~1.2eV碰撞能范围内计算了H(D,T)+OCl反应的反应截面和分支比等结果.同位素对反应截面和产物分支比的影响很明显,而对产物转动取向的影响不大.

  17. Quantum and quasi-classical dynamics of reaction H + DN (v = 0,1; j = 0) → HD + N and its isotopic variants

    Science.gov (United States)

    Li, Dan; Wang, Yuliang; Wumaier, Tuerdi

    2016-08-01

    Time-dependent wave packet (TDWP) and quasic-classical trajectory (QCT) methods were employed to study the title reaction and its isotopic variants on a new potential energy surface (PES) of 4A'' state over the range of collision energies, starting from the reaction threshold to 1.0 eV. We took the Coriolis coupling (CC) effect into account and presented the comparison between the CC and the centrifugal sudden (CS) approximation calculations. Reaction probabilities obtained using the different methods were thoroughly compared as a function of the collision energy for a series of total angular momentum J values. Significant differences of integral cross section between CC and CS results have been observed. The QCT-calculated cross sections and probabilities reproduced well the CC results over most of the collision energy range. In addition, the attack angle dependent reaction probabilities of the title reaction at J = 0 were calculated. The reaction probabilities were found to be strongly dependent on the attack angle. The influences of the reactant vibration excitation on the attack angle dependent reaction probabilities were also studied in detail.

  18. Research on Three-dimensional Modeling and Visualization for Well Trajectory of Drilling

    Directory of Open Access Journals (Sweden)

    Gao Xiaorong

    2013-09-01

    Full Text Available This study aims to realize 3D visualization of well trajectory more efficiently by use of a new method. In view of the shortcomings of traditional three-dimensional (3D modeling methods for well trajectory, a new method of slice-based 3D modeling for the tubular well trajectory was put forward, by which a 3D well trajectory model was established. The method can realize the 3D tubular well trajectory seamless connection efficiently and conveniently without interpolation smoothing treatment of the well trajectory’s crook. In order to provide a convenience to observe and analyze intuitively as well as control the well trajectory effectively in drilling for the drilling staff, realized 3D visualization of the well trajectory based on virtual reality technology and provided flexible human-computer interaction functions with which the drilling staff can make interactive operation such as zooming, translating and rotating, etc., for the 3D well trajectory. Consequently, the well trajectory can be observed from multi-azimuth and multi-angle, improving the oil reservoir encountering rate. Finally, an application example of 3D visualization for well trajectory in Dagang Oilfield was given.

  19. Developmental links between trajectories of physical violence, vandalism, theft, and alcohol-drug use from childhood to adolescence

    NARCIS (Netherlands)

    Koot, H.M..; Lier, van P.A.C.; Vitaro, F.; Tremblay, R.; Barker, E.D.

    2009-01-01

    Differences in developmental trajectories of physical violence, vandalism, theft, and alcohol-drug use from ages 10 to 15 were studied. For females and for males, three trajectories of theft and of alcohol-drug use increased from 10 years to 15 years, while only the high trajectory of vandalism

  20. Lumbar pedicle cortical bone trajectory screw

    Institute of Scientific and Technical Information of China (English)

    Song Tengfei; Wellington K Hsu; Ye Tianwen

    2014-01-01

    Objective The purpose of this study was to demonstrate the lumbar pedicle cortical bone trajectory (CBT) screw fixation technique,a new fixation technique for lumbar surgery.Data sources The data analyzed in this review are mainly from articles reported in PubMed published from 1994 to 2014.Study selection Original articles and critical reviews relevant to CBT technique and lumbar pedicle fixation were selected.Results CBT technique was firstly introduced as a new fixation method for lumbar pedicle surgery in 2009.The concepts,morphometric study,biomechanical characteristics and clinical applications of CBT technique were reviewed.The insertional point of CBT screw is located at the lateral point of the pars interarticularis,and its trajectory follows a caudocephalad path sagittally and a laterally directed path in the transverse plane.CBT technique can be used for posterior fixation during lumbar fusion procedures.This technique is a minimally invasive surgery,which affords better biomechanical stability,fixation strength and surgical safety.Therefore,CBT technique has the greatest benefit in lumbar pedicle surgery for patients with osteoporosis and obesity.Conclusion CBT technique is a better alternative option of lumbar pedicle fixation,especially for patients with osteoporosis and obesity.

  1. Mining spatiotemporal patterns of urban dwellers from taxi trajectory data

    Science.gov (United States)

    Mao, Feng; Ji, Minhe; Liu, Ting

    2016-06-01

    With the widespread adoption of locationaware technology, obtaining long-sequence, massive and high-accuracy spatiotemporal trajectory data of individuals has become increasingly popular in various geographic studies. Trajectory data of taxis, one of the most widely used inner-city travel modes, contain rich information about both road network traffic and travel behavior of passengers. Such data can be used to study the microscopic activity patterns of individuals as well as the macro system of urban spatial structures. This paper focuses on trajectories obtained from GPS-enabled taxis and their applications for mining urban commuting patterns. A novel approach is proposed to discover spatiotemporal patterns of household travel from the taxi trajectory dataset with a large number of point locations. The approach involves three critical steps: spatial clustering of taxi origin-destination (OD) based on urban traffic grids to discover potentially meaningful places, identifying threshold values from statistics of the OD clusters to extract urban jobs-housing structures, and visualization of analytic results to understand the spatial distribution and temporal trends of the revealed urban structures and implied household commuting behavior. A case study with a taxi trajectory dataset in Shanghai, China is presented to demonstrate and evaluate the proposed method.

  2. Life Course Trajectories of Later-Life Cognitive Functions: Does Social Engagement in Old Age Matter?

    Science.gov (United States)

    Park, Sojung; Kwon, Eunsun; Lee, Hyunjoo

    2017-04-07

    This study identified differential patterns of later-life cognitive function trajectories and examined to what extent life course factors and social engagement are associated with group trajectories. Data came from seven waves of the Health and Retirement Study (HRS 1998-2010; n = 7374; Observations = 41,051). Latent class growth analysis identified cognitive function trajectory groups, and multinomial logistic regression was used to examine the factors associated with group trajectories. Five heterogeneous trajectories were identified: stable high, stable moderate, stable low, high-to-moderate, and moderate-to-low. Findings suggest that, after adjusting for life course factors, individuals who became volunteers were more likely to belong to one of the two least vulnerable trajectories, stable high or high-to-moderate. Our findings suggest that, despite the cumulative life course factors evident in cognitive decline, social engagement in old age may serve as a potential protective resource.

  3. Simulation of molecular transitions using classical trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, A.; Martens, C. C. [University of California, California (United States)

    2001-03-01

    In the present work, we describe the implementation of a semiclassical method to study physical-chemical processes in molecular systems where electronic state transitions and quantum coherence play a dominant role. The method is based on classical trajectory propagation on the underlying coupled electronic surfaces and is derived from the semiclassical limit of the quantum Liouville equation. Unlike previous classical trajectory-based methods, quantum electronic coherence are treated naturally within this approach as complex weighted trajectory ensembles propagating on the average electronic surfaces. The method is tested on a model problem consisting of one-dimensional motion on two crossing electronic surfaces. Excellent agreement is obtained when compared to the exact results obtained by wave packet propagation. The method is applied to model quantum wave packet interferometry, where two wave packets, differing only in a relative phase, collide in the region where the two electronic surfaces cross. The dependence of the resulting population transfer on the initial relative phase of the wave packets is perfectly captured by our classical trajectory method. Comparison with an alternative method, surface hopping, shows that our approach is appropriate for modelling quantum interference phenomena. [Spanish] En este trabajo se describe la implementacion de un metodo semiclasico para estudiar procesos fisicos-quimicos en sistemas moleculares donde las transiciones entre estados electronicos y las coherencias cuanticas juegan un papel predominante. El metodo se basa en la propagacion de trayectorias clasicas sobre las correspondientes superficies electronicas acopladas y se deriva a partir del limite semiclasico de la ecuacion cuantica de Liouville. A diferencia de metodos previos basados en trayectoria clasica, dentro de este esquema, las coherencias electronicas cuanticas son tratadas de manera natural como ensamble de trayectorias con pesos complejos, moviendose en

  4. Mobility, education and life trajectories

    DEFF Research Database (Denmark)

    Olwig, Karen Fog; Valentin, Karen

    2015-01-01

    the perspective that education includes a broad range of formative experiences, the articles explore different educational trajectories and the local, regional and transnational relations in which they are embedded. Three key issues emerge from the analyses: firstly, the central role of temporality in terms...... of both the overall historical conditions and the specific biographical circumstances shaping educational opportunities; secondly, the complex agendas informing individuals’ migration and the adjustment of these agendas in the light of the vagaries of migrant life; and thirdly, the importance of migrants...

  5. Quantum Tunneling and Complex Trajectories

    Science.gov (United States)

    Meynig, Max; Haggard, Hal

    2017-01-01

    In general, the semiclassical approximation of quantum mechanical tunneling fails to treat tunneling through barriers if real initial conditions and trajectories are used. By analytically continuing classical dynamics to the complex plane the problems encountered in the approximation can be resolved. While, the complex methods discussed here have been previously explored, no one has exhibited an analytically solvable case. The essential features of the complex method will be discussed in the context of a novel, analytically solvable problem. These methods could be useful in quantum gravity, with applications to the tunneling of spacetime geometries.

  6. Quantum frictionless trajectories versus geodesics

    CERN Document Server

    Barbado, Luis C; Garay, Luis J

    2015-01-01

    Moving particles outside a star will generally experience quantum friction caused by Unruh radiation reaction. There exist however radial trajectories that lack this effect (in the outgoing radiation sector, and ignoring back-scattering). They turn out to have the property that the variations of the Doppler and the gravitational shifts compensate each other. They are not geodesics, and their proper acceleration obeys an inverse square law, which means that could in principle be generated by outgoing stellar radiation. In the case of a black hole emitting Hawking radiation, this may lead to a buoyancy scenario. The ingoing radiation sector has little effect and seems to slow down the fall even further.

  7. Privacy-Preserving Trajectory Collection

    DEFF Research Database (Denmark)

    Gidofalvi, Gyozo; Xuegang, Huang; Pedersen, Torben Bach

    2008-01-01

    In order to provide context--aware Location--Based Services, real location data of mobile users must be collected and analyzed by spatio--temporal data mining methods. However, the data mining methods need precise location data, while the mobile users want to protect their location privacy....... To remedy this situation, this paper first formally defines novel location privacy requirements. Then, it briefly presents a system for privacy--preserving trajectory collection that meets these requirements. The system is composed of an untrusted server and clients communicating in a P2P network. Location...

  8. Predicting adherence trajectory using initial patterns of medication filling.

    Science.gov (United States)

    Franklin, Jessica M; Krumme, Alexis A; Shrank, William H; Matlin, Olga S; Brennan, Troyen A; Choudhry, Niteesh K

    2015-09-01

    To evaluate the ability of initial medication dispensings to predict long-term patterns of adherence. A retrospective cohort study of statin initiators enrolled in a Medicare Part D drug plan from CVS Caremark from 2005 to 2008. We used group-based trajectory models to classify patients into 6 adherence trajectories based on patterns of statin filling over the year following therapy initiation. Baseline clinical characteristics and indicators of statin filling during the first 2 to 4 months following initiation were used to predict adherence trajectory in logistic regression models, separately within strata of the days' supply of the initial statin dispensing. Cross-validation was used to measure predictive accuracy of models in data not used for model estimation. Among 77,703 statin initiators, prediction using baseline variables only was poor (cross-validated C statistic ≤ 0.61). When using 3 months of initial adherence to predict trajectory, prediction was greatly improved among patients with an index supply ≤30 days (0.62 ≤ C ≤ 0.91). With 4 months of initial adherence in the model, prediction was strong for all patients (C ≥ 0.72), especially for the best and worst trajectories (C = 0.90 and 0.94, respectively, in patients with an index supply ≤ 30 days; and C = 0.83 and 0.90, respectively, in patients with an index supply > 30 days). Initial filling behavior strongly predicted future adherence trajectory. Predicting adherence trajectories may facilitate better targeting of interventions to patients most likely to benefit.

  9. Maternal age and trajectories of cannabis use.

    Science.gov (United States)

    De Genna, Natacha M; Cornelius, Marie D; Goldschmidt, Lidush; Day, Nancy L

    2015-11-01

    Becoming a mother is a developmental transition that has been linked to desistance from substance use. However, timing of motherhood may be a key determinant of cannabis use in women, based on preliminary evidence from teenage mothers. The goal of this study was to identify trajectories of maternal cannabis use, and to determine if maternal age was associated with different trajectories of use. This prospective study examined 456 pregnant women recruited at a prenatal clinic, ranging in age from 13 to 42 years. The women were interviewed about their cannabis use 1 year prior to pregnancy and during each trimester of pregnancy, and at 6, 10, 14, and 16 years post-partum. A growth mixture model of cannabis use reported at each time point clearly delineated four groups: non/unlikely to use, decreasing likelihood of use, late desistance, and increasing likelihood/chronic use (Lo-Mendell-Rubin adjusted LRT test statistic=35.7, pcannabis across 17 years, including later desistance post-partum and increasing/chronic use. Other substance use and chronic depressive symptoms were also associated with more frequent use. These findings have implications for both prevention and treatment of cannabis use in mothers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. A new (multi-reference configuration interaction) potential energy surface for H2CO and preliminary studies of roaming

    Science.gov (United States)

    Wang, Xiaohong; Houston, Paul L.; Bowman, Joel M.

    2017-03-01

    We report a new global potential energy surface (PES) for H2CO, based on precise fitting of roughly 67 000 MRCI/cc-pVTZ energies. This PES describes the global minimum, the cis- and trans-HCOH isomers, and barriers relevant to isomerization, formation of the molecular (H2+CO) and radical (H+HCO) products, and the loose so-called roaming transition-state saddle point. The key features of the PES are reviewed and compared with a previous PES, denoted by PES04, based on five local fits that are `stitched' together by switching functions (Zhang et al. 2004 J. Phys. Chem. A 108, 8980-8986 (doi:10.1021/jp048339l)). Preliminary quasi-classical trajectory calculations are performed at the total energy of 36 233 cm-1 (103 kcal mol-1), relative to the H2CO global minimum, using the new PES, with a particular focus on roaming dynamics. When compared with the results from PES04, the new PES findings show similar rotational distributions, somewhat more roaming and substantially higher H2 vibrational excitation. This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  11. Radarsat observations and forecasting of oil slick trajectory movements

    Institute of Scientific and Technical Information of China (English)

    Maged Marghany

    2004-01-01

    RADARSAT data have a potential role for coastal pollution monitoring. This study presents a new approach to detect and forecast oil slick trajectory movements. The oil slick trajectory movements is based on the tidal current effects and Fay's algorithm for oil slick spreading mechanisms. The oil spill trajectory model contains the integration between Doppler frequency shift model and Lagrangian model. Doppler frequency shift model implemented to simulate tidal current pattern from RADARSAT data while the Lagrangian model used to predict oil spill spreading pattern. The classical Fay's algorithm was implemented with the two models to simulate the oil spill trajectory movements.The study shows that the slick lengths are effected by tidal current V component with maximum velocity of 1.4 m/s. This indicates thatoil slick trajectory path is moved towards the north direction. The oil slick parcels are accumulated along the coastline after 48 h. Theanalysis indicated that tidal current V components were the dominant forcing for oil slick spreading.

  12. Trajectory Codes for Flash Memory

    CERN Document Server

    Anxiao,; Langberg, Michael; Schwartz, Moshe; Bruck, Jehoshua

    2010-01-01

    Flash memory is well-known for its inherent asymmetry: the flash-cell charge levels are easy to increase but are hard to decrease. In a general rewriting model, the stored data changes its value with certain patterns. The patterns of data updates are determined by the data structure and the application, and are independent of the constraints imposed by the storage medium. Thus, an appropriate coding scheme is needed so that the data changes can be updated and stored efficiently under the storage-medium's constraints. In this paper, we define the general rewriting problem using a graph model. It extends many known rewriting models such as floating codes, WOM codes, buffer codes, etc. We present a new rewriting scheme for flash memories, called the trajectory code, for rewriting the stored data as many times as possible without block erasures. We prove that the trajectory code is asymptotically optimal in a wide range of scenarios. We also present randomized rewriting codes optimized for expected performance (g...

  13. Third-order trajectory planning for high accuracy point-to-point motion

    Institute of Scientific and Technical Information of China (English)

    Haihua MU; Yunfei ZHOU; Sijie YAN; Aiguo HAN

    2009-01-01

    This article studies a third-order trajectory planning method for point-to-point motion.All available instances for third-order trajectory planning are first ana-lyzed.To distinguish those,threecriteria are presented relying on trajectory characteristics.Following that,a fast preprocessing approach considering the trajectory as a whole is given based on the criteria constructed and system constraints.Also,the time-optimality of the trajectory is obtained.The relevant formulas are derived with the combination of geometrical symmetry of trajectory and area method.As a result,an accurate algorithm and its implementation procedure are proposed.The experimental results show the effectiveness and precision of the pro-posed method.The presented algorithm has been applied in semiconductor manufacturing equipment successfully.

  14. Pseudospectral method based trajectory optimization and fairing rejection time analysis of solid launch vehicle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The problem of real-time trajectory optimization for small solid launch vehicle of operational responsive space (ORS) was studied by using pseudospectral method. According to the characteristic of the trajectory design, the dynamics model was set up in the inertia right-angled reference frame, and the equation and parameter at the orbit injection point were simplified and converted. The infinite dimension dynamic optimal control problem was converted to a finite dimension static state optimization problem and the algorithm reduced the complexity so as to become a general algorithm in trajectories optimization. With the trajectories optimization of a three-stage solid vehicle with a liquor upper stage as example, the model of the trajectory optimization was set up and simulations were carried out. The results demonstrated the advantage and validity of the pseudospectral method. The rejection time of fairing was also analyzed by the simulation results, and the optimal flight procedure and trajectory were obtained.

  15. Is the Regge Trajectory Quasi-linear or Square-root Form?

    CERN Document Server

    Li, Zhen

    2016-01-01

    There are many orbital excited mesons discovered in recent years. In this work we attempt to study whether the Regge trajectory is quasi-linear or square-root form. In the framework of the quasi-linear Regge trajectory and square-root Regge trajectory, the masses of the states lying on the well established 11S0, 13S1, and 13P2 trajectories are estimated. Comparison of the results given by the two trajectories with the existing experimental data illustrates that both of them can give a reasonable description for the ground mesons. For the orbital excited states, the quasi-linear trajectory describes the existing meson spectrum to be more reasonable.

  16. Global and Local Color Time Scales to Encode Timeline Events in Ion Trajectories for Glassies

    Directory of Open Access Journals (Sweden)

    J. M. Sharif

    2015-02-01

    Full Text Available Glassy compounds lead directly to high ionic conductivity. Ionic conductivity generates ion trajectories. However, these trajectories have been represented by two-dimensional graph in order to visualize the timeline events in ion trajectories. This study addresses this problem by encoding the timeline events in ion trajectories with global and local color scales. Two time scales have been introduced namely Global Color Time Scale and Local Color Time Scale. The rainbow color has been chosen to represent global time scale meanwhile solid color has been used to generate local time scale. Based on evaluation, these techniques are successful in representing timeline events in ion trajectories for understanding the complicated heterogeneous movement of ion trajectories.

  17. Trajectories of dental anxiety in a birth cohort

    Science.gov (United States)

    Thomson, W. M.; Broadbent, J. M.; Locker, D.; Poulton, R.

    2010-01-01

    Objective To examine predictors of dental anxiety trajectories in a longitudinal study of New Zealanders. Methods Prospective study of a complete birth cohort born in 1972/73 in Dunedin, New Zealand, with dental anxiety scale (DAS) scores and dental utilization determined at ages 15, 18, 26 and 32 years. Personality traits were assessed at a superfactor and (more fine-grained) subscale level via the Multidimensional Personality Questionnaire at age 18 years. Group-based trajectory analysis was used to identify dental anxiety trajectories. Results DAS scores from at least three assessments were available for 828 participants. Six dental anxiety trajectories were observed: stable nonanxious low (39.6%); stable nonanxious medium (37.9%); recovery (1.6%); adult-onset anxious (7.7%); stable anxious (7.2%) and adolescent-onset anxious (5.9%). Multivariate analysis showed that males and those with higher DMFS at age 15 years were more likely to be in the stable nonanxious low trajectory group. Membership of the stable nonanxious medium group was predicted by the dental caries experience at age 15 years. Participants who had lost one or more teeth between ages 26 and 32 years had almost twice the relative risk for membership of the adult-onset anxious group. Personality traits predicted group membership. Specifically, high scorers (via median split) on the ‘stress reaction’ subscale had over twice the risk of being in the stable anxious group; low scorers on the traditionalism subscale were more likely to be members of the recovery trajectory group; and high scorers on the ‘social closeness’ subscale had half the risk of being in the stable anxious group. Dental caries experience at age 5 years was also a predictor for the stable anxious group. Membership of the late-adolescent-onset anxious group was predicted by higher dental caries experience by age 15 years, but none of the other predictors was significant. Conclusion Six discrete trajectories of dental anxiety

  18. Winding light beams along elliptical helical trajectories

    CERN Document Server

    Wen, Yuanhui; Zhang, Yanfeng; Chen, Hui; Yu, Siyuan

    2016-01-01

    Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We develop a superposition caustic method capable of winding light beams along non-convex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implement the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of non-convex trajectories, thereby opening up a new route of manipulating light beams for fundamental research and practical ap...

  19. Stochastic and fractal analysis of fracture trajectories

    Science.gov (United States)

    Bessendorf, Michael H.

    1987-01-01

    Analyses of fracture trajectories are used to investigate structures that fall between 'micro' and 'macro' scales. It was shown that fracture trajectories belong to the class of nonstationary processes. It was also found that correlation distance, which may be related to a characteristic size of a fracture process, increases with crack length. An assemblage of crack trajectory processes may be considered as a diffusive process. Chudnovsky (1981-1985) introduced a 'crack diffusion coefficient' d which reflects the ability of the material to deviate the crack trajectory from the most energetically efficient path and thus links the material toughness to its structure. For the set of fracture trajectories in AISI 304 steel, d was found to be equal to 1.04 microns. The fractal dimension D for the same set of trajectories was found to be 1.133.

  20. Center of pressure trajectory differences between shod and barefoot running.

    Science.gov (United States)

    Becker, James; Pisciotta, Eric; James, Stan; Osternig, Louis R; Chou, Li-Shan

    2014-09-01

    This study examined differences in center of pressure (COP) trajectories between shod and barefoot running. Ten habitually shod runners ran continuous laps under both shod and barefoot conditions. The COP trajectory was calculated in the global coordinate system but then transformed to the anatomic coordinate system of the foot. The anterior-posterior and medio-lateral positions and excursions of the COP, as well as the most medial location and percent stand at which it occurred were examined. Additionally, external eversion moments and ground reaction forces were assessed. Compared to the shod condition, in the barefoot condition the COP was located more anteriorly early in stance and the COP was located significantly more medially at most time points across stance. There were no differences in external eversion moments during early stance or peak ground reaction forces between conditions. Future studies on mechanical or epidemiological differences between shod and barefoot running may find the COP trajectory an informative parameter to examine.