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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 the energy transfer in CO2--rare gas systems

    International Nuclear Information System (INIS)

    Suzukawa, H.H. Jr.; Wolfsberg, M.; Thompson, D.L.

    1978-01-01

    Computational methods are presented for the study of collisions between a linear, symmetric triatomic molecule and an atom by three-dimensional quasiclassical trajectory calculations. Application is made to the investigation of translational to rotational and translational to vibrational energy transfer in the systems CO 2 --Kr, CO 2 --Ar, and CO 2 --Ne. Potential-energy surfaces based on spectroscopic and molecular beam scattering data are used. In most of the calculations, the CO 2 molecule is initially in the quantum mechanical zero-point vibrational state and in a rotational state picked from a Boltzmann distribution at 300 0 K. The energy transfer processes are investigated for translational energies ranging from 0.1 to 10 eV. Translational to rotational energy transfer is found to be the major process for CO 2 --rare gas collisions at these energies. Below 1 eV there is very little translational to vibrational energy transfer. The effects of changes in the internal energy of the molecule, in the masses of the collidants, and in the potential-energy parameters are studied in an attempt to gain understanding of the energy transfer processes

  3. A quasiclassical trajectory analysis of stereodynamics of the H + FCl ...

    Indian Academy of Sciences (India)

    Abstract. 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 polarization- dependent ...

  4. Quasi-classical trajectory study of the reaction H + HS on a new ab ...

    Indian Academy of Sciences (India)

    CBS PES) by fitting accu- rate multireference configuration interaction energies .... 2.3 QCT calculations. We employed the standard QCT method (see the details in Refs 4–7 and the references therein) to study the stereodynamics of the title ...

  5. Quasiclassical trajectory study of the molecular beam kinetics of the deuterium atom--hydrogen halide exchange reactions

    International Nuclear Information System (INIS)

    Raff, L.M.; Suzukawa, H.H. Jr.; Thompson, D.L.

    1975-01-01

    Unadjusted quasiclassical trajectory computations have been carried out to simulate the molecular beam scattering of thermal D atom beams at 2800 degreeK crossed with beams of HCl and HI at 250 degreeK. Total reaction cross sections, energy partitioning distributions, and differential scattering cross sections have been computed for the exchange reactions D+HCl → DCl+H and D+HI → DI+H while total reaction cross sections are reported for the corresponding abstractions, i.e., D+HCl → HD+Cl and D+HI → HD+I. For the exchange reactions, the computed reaction cross sections are within the range estimated from the crossed beam experiments. The calculated average energy partitioned into relative translational motion of products is in near quantitative agreement with the beam results, and the predicted differential scattering cross sections appear to be in qualitative accord with the beam experiments. The over-all agreement between theory and experiment indicates that previously computed values for the thermal rate coefficients for the exchange reactions are of the right order and that a systematic error exists in the interpretation of photolysis data in the hydrogen--hydrogen halide systems

  6. Exact quantum dynamics study of the O++H2(v=0,j=0)→OH++H ion-molecule reaction and comparison with quasiclassical trajectory calculations

    International Nuclear Information System (INIS)

    Martinez, Rodrigo; Lucas, Josep M.; Gimenez, Xavier; Aguilar, Antonio; Gonzalez, Miguel

    2006-01-01

    The close-coupling hyperspherical (CCH) exact quantum method was used to study the title barrierless reaction up to a collision energy (E T ) of 0.75 eV, and the results compared with quasiclassical trajectory (QCT) calculations to determine the importance of quantum effects. The CCH integral cross section decreased with E T and, although the QCT results were in general quite similar to the CCH ones, they presented a significant deviation from the CCH data within the 0.2-0.6 eV collision energy range, where the QCT method did not correctly describe the reaction probability. A very good accord between both methods was obtained for the OH + vibrational distribution, where no inversion of population was found. For the OH + rotational distributions, the agreement between the CCH and QCT results was not as good as in the vibrational case, but it was satisfactory in many conditions. The kk ' angular distribution showed a preferential forward character, and the CCH method produced higher forward peaks than the QCT one. All the results were interpreted considering the potential energy surface and plots of a representative sampling of reactive trajectories

  7. Mode specific dynamics of the H2 + CH3 → H + CH4 reaction studied using quasi-classical trajectory and eight-dimensional quantum dynamics methods

    International Nuclear Information System (INIS)

    Wang, Yan; Li, Jun; Guo, Hua; Chen, Liuyang; Yang, Minghui; Lu, Yunpeng

    2015-01-01

    An eight-dimensional quantum dynamical model is proposed and applied to the title reaction. The reaction probabilities and integral cross sections have been determined for both the ground and excited vibrational states of the two reactants. The results indicate that the H 2 stretching and CH 3 umbrella modes, along with the translational energy, strongly promote the reactivity, while the CH 3 symmetric stretching mode has a negligible effect. The observed mode specificity is confirmed by full-dimensional quasi-classical trajectory calculations. The mode specificity can be interpreted by the recently proposed sudden vector projection model, which attributes the enhancement effects of the reactant modes to their strong couplings with the reaction coordinate at the transition state

  8. Crossed Molecular Beams and Quasiclassical Trajectory Surface Hopping Studies of the Multichannel Nonadiabatic O((3)P) + Ethylene Reaction at High Collision Energy.

    Science.gov (United States)

    Balucani, Nadia; Leonori, Francesca; Casavecchia, Piergiorgio; Fu, Bina; Bowman, Joel M

    2015-12-17

    The combustion relevant O((3)P) + C2H4 reaction stands out as a prototypical multichannel nonadiabatic reaction involving both triplet and singlet potential energy surfaces (PESs), which are strongly coupled. Crossed molecular beam (CMB) scattering experiments with universal soft electron ionization mass spectrometric detection have been used to characterize the dynamics of this reaction at the relatively high collision energy Ec of 13.7 kcal/mol, attained by crossing the reactant beams at an angle of 135°. This work is a full report of the data at the highest Ec investigated for this reaction. From laboratory product angular and velocity distribution measurements, angular and translational energy distributions in the center-of-mass system have been obtained for the five observed exothermic competing reaction channels leading to H + CH2CHO, H + CH3CO, CH3 + HCO, CH2 + H2CO, and H2 + CH2CO. The product branching ratios (BRs) have been derived. The elucidation of the reaction dynamics is assisted by synergic full-dimensional quasiclassical trajectory surface-hopping calculations of the reactive differential cross sections on coupled ab initio triplet/singlet PESs. This joint experimental/theoretical study extends and complements our previous combined CMB and theoretical work at the lower collision energy of 8.4 kcal/mol. The theoretically derived BRs and extent of intersystem crossing (ISC) are compared with experimental results. In particular, the predictions of the QCT results for the three main channels (those leading to vinoxy + H, methyl + HCO and methylene + H2CO formation) are compared directly with the experimental data in the laboratory frame. Good overall agreement is noted between theory and experiment, although some small, yet significant shortcomings of the theoretical differential cross section are noted. Both experiment and theory find almost an equal contribution from the triplet and singlet surfaces to the reaction, with a clear tendency of the

  9. Quasi-classical trajectory study of the role of vibrational and translational energy in the Cl(2P) + NH3 reaction.

    Science.gov (United States)

    Monge-Palacios, M; Corchado, J C; Espinosa-Garcia, J

    2012-05-28

    A detailed state-to-state dynamics study was performed to analyze the effects of vibrational excitation and translational energy on the dynamics of the Cl((2)P) + NH(3)(v) gas-phase reaction, effects which are connected to such issues as mode selectivity and Polanyi's rules. This reaction evolves along two deep wells in the entry and exit channels. At low and high collision energies quasi-classical trajectory calculations were performed on an analytical potential energy surface previously developed by our group, together with a simplified model surface in which the reactant well is removed to analyze the influence of this well. While at high energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity by a factor ≈1.1-2.9 with respect to the vibrational ground-state, at low energy the opposite behaviour is found (factor ≈ 0.4-0.9). However, when the simplified model surface is used at low energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity, showing that the behaviour at low energies is a direct consequence of the existence of the reactant well. Moreover, we find that this reaction exhibits negligible mode selectivity, first because the independent excitation of the N-H symmetric and asymmetric stretch modes, which lie within 200 cm(-1) of each other, leads to reactions with similar reaction probabilities, and second because the vibrational excitation of the reactive N-H stretch mode is only partially retained in the products. For this "late transition-state" reaction, we also find that vibrational energy is more effective in driving the reaction than an equivalent amount of energy in translation, consistent with an extension of Polanyi's rules. Finally, we find that the non-reactive events, Cl((2)P)+NH(3)(v) → Cl((2)P) + NH(3)(v'), lead to a great number of populated vibrational states in the NH(3)(v') product, even starting from the NH(3)(v = 0) vibrational ground state at low energies

  10. 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.

  11. Ab initio analytical potential energy surface and quasiclassical trajectory study of the O+(4S)+H2(X 1Σg+)→OH+(X 3Σ-)+H(2S) reaction and isotopic variants

    International Nuclear Information System (INIS)

    Martinez, Rodrigo; Millan, Judith; Gonzalez, Miguel

    2004-01-01

    An analytical potential energy surface (PES) representation of the O + ( 4 S)+H 2 (X 1 Σ g + ) system was developed by fitting around 600 CCSD(T)/cc-pVQZ ab initio points. Rate constant calculations for this reaction and its isotopic variants (D 2 and HD) were performed using the quasiclassical trajectory (QCT) method, obtaining a good agreement with experimental data. Calculations conducted to determine the cross section of the title reaction, considering collision energies (E T ) below 0.3 eV, also led to good accord with experiments. This PES appears to be suitable for kinetics and dynamics studies. Moreover, the QCT results show that, although the hypotheses of a widely used capture model are not satisfied, the resulting expression for the cross section can be applied within a suitable E T interval, due to errors cancellation. This could be a general situation regarding the application of this simple model to ion-molecule processes

  12. Formaldehyde roaming dynamics: Comparison of quasi-classical trajectory calculations and experiments.

    Science.gov (United States)

    Houston, Paul L; Wang, Xiaohong; Ghosh, Aryya; Bowman, Joel M; Quinn, Mitchell S; Kable, Scott H

    2017-07-07

    The photodissociation dynamics of roaming in formaldehyde are studied by comparing quasi-classical trajectory calculations performed on a new potential energy surface (PES) to new and detailed experimental results detailing the CO + H 2 product state distributions and their correlations. The new PES proves to be a significant improvement over the past one, now more than a decade old. The new experiments probe both the CO and H 2 products of the formaldehyde dissociation. The experimental and trajectory data offer unprecedented detail about the correlations between internal states of the CO and H 2 dissociation products as well as information on how these distributions are different for the roaming and transition-state pathways. The data investigated include, for dissociation on the formaldehyde 2 1 4 3 band, (a) the speed distributions for individual vibrational/rotational states of the CO products, providing information about the correlated internal energy distributions of the H 2 product, and (b) the rotational and vibrational distributions for the CO and H 2 products as well as the contributions to each from both the transition state and roaming channels. The agreement between the trajectory and experimental data is quite satisfactory, although minor differences are noted. The general agreement provides support for future use of the experimental techniques and the new PES in understanding the dynamics of photodissociative processes.

  13. Cross sections of the O++H2→OH++H ion-molecule reaction and isotopic variants (D2, HD): Quasiclassical trajectory study and comparison with experiments

    International Nuclear Information System (INIS)

    Martinez, Rodrigo; Sierra, Jose Daniel; Gonzalez, Miguel

    2005-01-01

    A dynamics study [cross section and microscopic mechanism versus collision energy (E T )] of the reaction O + +H 2 →OH + +H, which plays an important role in Earth's ionosphere and interstellar chemistry, was conducted using the quasiclassical trajectory method, employing an analytical potential energy surface (PES) recently derived by our group [R. Martinez et al., J. Chem. Phys. 120, 4705 (2004)]. Experimental excitation functions for the title reaction, as well as its isotopic variants with D 2 and HD, were near-quantitatively reproduced in the calculations in the very broad collision energy range explored (E T =0.01-6.0 eV). Intramolecular and intermolecular isotopic effects were also examined, yielding data in good agreement with experimental results. The reaction occurs via two microscopic mechanisms (direct and nondirect abstraction). The results were satisfactorily interpreted based on the reaction probability and the maximum impact parameter dependences with E T , and considering the influence of the collinear [OHH] + absolute minimum of the PES on the evolution from reactants to products. The agreement between theory and experiment suggests that the reaction mainly occurs through the lowest energy PES and nonadiabatic processes are not very important in the wide collision energy range analyzed. Hence, the PES used to describe this reaction is suitable for both kinetics and dynamics studies

  14. A quasiclassical trajectory study for the N(4S)+O2(X3Σg-)->NO(X2Π)+O(3P) atmospheric reaction based on a new ground potential energy surface

    International Nuclear Information System (INIS)

    He Jianfeng; Liu Shixing; Liu Xueshen; Ding Peizhu

    2005-01-01

    A quasiclassical trajectory study with the fourth-order explicit symplectic algorithm for the N( 4 S)+O 2 (X 3 Σ g - )->NO(X 2 Π)+O( 3 P) atmospheric reaction has been performed by employing a new analytical fit of ab initio electronic structure calculations for the ground potential energy surface reported by Sayos et al. The effect of the relative translational energy, the vibrational energy and rotational energy of O 2 molecule on the reaction probability and the reaction cross-section has been analyzed in details. The microscopic rate constant and the thermal rate constant have also been evaluated at the low translational temperature, and results have been compared with the experimental data and previous theoretical values. It is concluded that the thermal rate constants at the low temperature considered in this work agree well with the recommended experimental data and are very close to the variational transition state theory values carried out by Sayos et al

  15. Investigation of oxygen vibrational relaxation by quasi-classical trajectory method

    International Nuclear Information System (INIS)

    Andrienko, Daniil; Boyd, Iain D.

    2015-01-01

    Highlights: • Importance of attraction for the O 2 –O energy exchange in hypersonic flows. • O 2 –O vibrational relaxation time cannot be described by the Millikan–White equation. • Weak dependence of exothermic transition rates on translational temperature. • Multiquantum jumps in molecular oxygen occur mostly via the exchange reaction. - Abstract: O 2 –O collisions are studied by the quasi-classical trajectory method. A full set of cross sections for the vibrational ladder is obtained utilizing an accurate O 3 potential energy surface. Vibrational relaxation is investigated at temperatures between 1000 and 10,000 K, that are relevant to hypersonic flows. The relaxation time is derived based on the removal rate for the first excited vibrational level. A significant deviation from the formula by Millikan and White is observed for temperatures beyond those reported in experimental work. Relaxation becomes less efficient at high temperatures, suggesting that the efficiency of the energy randomization is strongly to the attractive component of the O 3 potential energy surface. These results are explained by analyzing the microscopic parameter of collisions that reflects the number of exchanges in the shortest interatomic distance. The rates of exothermic transitions are found to be nearly independent of the translational temperature in the range of interest.

  16. Symmetrical Windowing for Quantum States in Quasi-Classical Trajectory Simulations

    Science.gov (United States)

    Cotton, Stephen Joshua

    An approach has been developed for extracting approximate quantum state-to-state information from classical trajectory simulations which "quantizes" symmetrically both the initial and final classical actions associated with the degrees of freedom of interest using quantum number bins (or "window functions") which are significantly narrower than unit-width. This approach thus imposes a more stringent quantization condition on classical trajectory simulations than has been traditionally employed, while doing so in a manner that is time-symmetric and microscopically reversible. To demonstrate this "symmetric quasi-classical" (SQC) approach for a simple real system, collinear H + H2 reactive scattering calculations were performed [S.J. Cotton and W.H. Miller, J. Phys. Chem. A 117, 7190 (2013)] with SQC-quantization applied to the H 2 vibrational degree of freedom (DOF). It was seen that the use of window functions of approximately 1/2-unit width led to calculated reaction probabilities in very good agreement with quantum mechanical results over the threshold energy region, representing a significant improvement over what is obtained using the traditional quasi-classical procedure. The SQC approach was then applied [S.J. Cotton and W.H. Miller, J. Chem. Phys. 139, 234112 (2013)] to the much more interesting and challenging problem of incorporating non-adiabatic effects into what would otherwise be standard classical trajectory simulations. To do this, the classical Meyer-Miller (MM) Hamiltonian was used to model the electronic DOFs, with SQC-quantization applied to the classical "electronic" actions of the MM model---representing the occupations of the electronic states---in order to extract the electronic state population dynamics. It was demonstrated that if one ties the zero-point energy (ZPE) of the electronic DOFs to the SQC windowing function's width parameter this very simple SQC/MM approach is capable of quantitatively reproducing quantum mechanical results for

  17. Quasi-classical trajectory approach to the O(1D)+HBr→OH+Br reaction stereo-dynamics on X1A' potential energy surface

    International Nuclear Information System (INIS)

    Li Hong; Zheng Bin; Yin Ji-Qing; Meng Qing-Tian

    2011-01-01

    The vector properties of reaction O( 1 D)+HBr→OH+Br on the potential energy surface (PES) of X 1 A' ground singlet state are studied by using the quasi-classical trajectory (QCT) theory. The polarization-dependent differential cross sections (PDDCSs), the average rotational alignment factor 2 (j' · k)>, as well as the distributions reflecting vector correlations are also computed. The analysis of the results shows that the alignment and the orientation distribution of the rotation angular momentum vector of product molecule OH is influenced by both the effect of heavy—light—heavy (HLH) type mass combination and the deep well of PES. (atomic and molecular physics)

  18. Quasiclassical trajectory studies of the O(3P) + CX4(vk = 0, 1) → OXv + CX3(n1n2n3n4) [X = H and D] reactions on an ab initio potential energy surface.

    Science.gov (United States)

    Czakó, Gábor; Liu, Rui; Yang, Minghui; Bowman, Joel M; Guo, Hua

    2013-08-01

    We report quasiclassical trajectory calculations of the integral and differential cross sections and the mode-specific product state distributions for the "central-barrier" O((3)P) + CH4/CD4(vk = 0, 1) [k = 1, 2, 3, 4] reactions using a full-dimensional ab initio potential energy surface. The mode-specific vibrational distributions for the polyatomic methyl products are obtained by doing a normal-mode analysis in the Eckart frame, followed by standard histogram binning (HB) and energy-based Gaussian binning (1GB). The reactant bending excitations slightly enhance the reactivity, whereas stretching excitations activate the reaction more efficiently. None of the reactant vibrational excitations is as efficient as an equivalent amount of translational energy to promote the reactions. The excitation functions without product zero-point energy (ZPE) constraint are in good agreement with previous 8-dimensional quantum mechanical (QM) results for the ground-state and stretching-excited O + CH4 reactions, whereas for the bending-excited reactions the soft ZPE constraint, which is applied to the sum of the product vibrational energies, provides better agreement with the QM cross sections. All angular distributions show the dominance of backward scattering indicating a direct rebound mechanism, in agreement with experiment. The title reactions produce mainly OH/OD(v = 0) products for all the initial states. HB significantly overestimates the populations of OH/OD(v = 1), especially in the energetic threshold regions, whereas 1GB provides physically correct results. The CH3/CD3 vibrational distributions show dominant populations for ground (v = 0), umbrella-excited (v2 = 1, 2), in-plane-bending-excited (v4 = 1), and v2 + v4 methyl product states. Neither translational energy nor reactant vibrational excitation transfers significantly into product vibrations.

  19. Collisional Dissociation of CO: ab initio Potential Energy Surfaces and Quasiclassical Trajectory Rate Coefficients

    Science.gov (United States)

    Schwenke, David W.; Jaffe, Richard L.; Chaban, Galina M.

    2016-01-01

    We have generated accurate global potential energy surfaces for CO+Ar and CO+O that correlate with atom-diatom pairs in their ground electronic states based on extensive ab initio electronic structure calculations and used these potentials in quasi-classical trajectory nuclear dynamics calculations to predict the thermal dissociation rate coefficients over 5000- 35000 K. Our results are not compatible with the 20-45 year old experimental results. For CO + Ar we obtain fairly good agreement with the experimental rate coefficients of Appleton et al. (1970) and Mick and Roth (1993), but our computed rate coefficients exhibit a stronger temperature dependence. For CO + O our dissociation rate coefficient is in close agreement with the value from the Park model, which is an empirical adjustment of older experimental results. However, we find the rate coefficient for CO + O is only 1.5 to 3.3 times larger than CO + Ar over the temperature range of the shock tube experiments (8000-15,000 K). The previously accepted value for this rate coefficient ratio is 15, independent of temperature. We also computed the rate coefficient for the CO + O ex- change reaction which forms C + O2. We find this reaction is much faster than previously believed and is the dominant process in the removal of CO at temperatures up to 16,000 K. As a result, the dissociation of CO is accomplished in two steps (react to form C+O2 and then O2 dissociates) that are endothermic by 6.1 and 5.1 eV, instead of one step that requires 11.2 eV to break the CO bond.

  20. Quasiclassical studies of phase-coherent transport in superconducting nanostructures

    International Nuclear Information System (INIS)

    Seviour, R.F.

    1999-07-01

    In chapter two we introduce the quasiclassical technique and analysis the subgap conductance in S/N structures with barriers (zero bias and finite bias anomalies). We also analyse an Andreev interferometer. Also we present the results of studies on the Josephson effect in 4 terminal S/N/S contacts and on the possible sign reversal of the Josephson critical current (Published in Superlattices and Microstructures, Vol. 25, No. 5/6, p. 647 (1999)). In chapters three and four using the quasiclassical technique in conjunction with a numerical scattering approach (see Appendix) we consider a normal-superconducting-normal structure. In these chapters we consider the effects of the interface resistance between the Normal reservoirs and the normal film and the interface resistance between the superconductor and the normal film. This work has been published in J.Phys.Conds.Mat. 10 (1998), L615 and PHYS REV B 1 Nov 98. In Chapter 5 using the techniques discussed above we shown that for normal-superconducting-normal structure a new peek may arise in the temperature dependence of the conductance when the temperature is approximately equal to the transition temperature of the superconducting (Published PHYS. Rev.13, 1999, v.59, No.9, p. 6031). In chapter 6 we analyse the first ever experimental results showing the new peak in the conductance as discussed in chapter 5 (Submitted to PRL). Chapter 7 uses the numerical technique discussed in the appendix. to examine the phenomena of conductance suppression in 4 probe normal superconducting structures (Published Superlattices and Microstructures, Vol. 25, No.5, p. 640 (1999)). (author)

  1. Importance sampling and histogrammic representations of reactivity functions and product distributions in Monte Carlo quasiclassical trajectory calculations

    International Nuclear Information System (INIS)

    Faist, M.B.; Muckerman, J.T.; Schubert, F.E.

    1978-01-01

    The application of importance sampling as a variance reduction technique in Monte Carlo quasiclassical trajectory calculations is discussed. Two measures are proposed which quantify the quality of the importance sampling used, and indicate whether further improvements may be obtained by some other choice of importance sampling function. A general procedure for constructing standardized histogrammic representations of differential functions which integrate to the appropriate integral value obtained from a trajectory calculation is presented. Two criteria for ''optimum'' binning of these histogrammic representations of differential functions are suggested. These are (1) that each bin makes an equal contribution to the integral value, and (2) each bin has the same relative error. Numerical examples illustrating these sampling and binning concepts are provided

  2. Construction of a coarse-grain quasi-classical trajectory method. II. Comparison against the direct molecular simulation method

    Science.gov (United States)

    Macdonald, R. L.; Grover, M. S.; Schwartzentruber, T. E.; Panesi, M.

    2018-02-01

    This work presents the analysis of non-equilibrium energy transfer and dissociation of nitrogen molecules (N2(g+1Σ) ) using two different approaches: the direct molecular simulation (DMS) method and the coarse-grain quasi-classical trajectory (CG-QCT) method. The two methods are used to study thermochemical relaxation in a zero-dimensional isochoric and isothermal reactor in which the nitrogen molecules are heated to several thousand degrees Kelvin, forcing the system into strong non-equilibrium. The analysis considers thermochemical relaxation for temperatures ranging from 10 000 to 25 000 K. Both methods make use of the same potential energy surface for the N2(g+1Σ ) -N2(g+1Σ ) system taken from the NASA Ames quantum chemistry database. Within the CG-QCT method, the rovibrational energy levels of the electronic ground state of the nitrogen molecule are lumped into a reduced number of bins. Two different grouping strategies are used: the more conventional vibrational-based grouping, widely used in the literature, and energy-based grouping. The analysis of both the internal state populations and concentration profiles show excellent agreement between the energy-based grouping and the DMS solutions. During the energy transfer process, discrepancies arise between the energy-based grouping and DMS solution due to the increased importance of mode separation for low energy states. By contrast, the vibrational grouping, traditionally considered state-of-the-art, captures well the behavior of the energy relaxation but fails to consistently predict the dissociation process. The deficiency of the vibrational grouping model is due to the assumption of strict mode separation and equilibrium of rotational energy states. These assumptions result in errors predicting the energy contribution to dissociation from the rotational and vibrational modes, with rotational energy actually contributing 30%-40% of the energy required to dissociate a molecule. This work confirms the

  3. Communication: Rate coefficients from quasiclassical trajectory calculations from the reverse reaction: The Mu + H2 reaction re-visited

    Science.gov (United States)

    Homayoon, Zahra; Jambrina, Pablo G.; Aoiz, F. Javier; Bowman, Joel M.

    2012-07-01

    In a previous paper [P. G. Jambrina et al., J. Chem. Phys. 135, 034310 (2011), 10.1063/1.3611400] various calculations of the rate coefficient for the Mu + H2 → MuH + H reaction were presented and compared to experiment. The widely used standard quasiclassical trajectory (QCT) method was shown to overestimate the rate coefficients by several orders of magnitude over the temperature range 200-1000 K. This was attributed to a major failure of that method to describe the correct threshold for the reaction owing to the large difference in zero-point energies (ZPE) of the reactant H2 and product MuH (˜0.32 eV). In this Communication we show that by performing standard QCT calculations for the reverse reaction and then applying detailed balance, the resulting rate coefficient is in very good agreement with the other computational results that respect the ZPE, (as well as with the experiment) but which are more demanding computationally.

  4. Classical and quasi-classical trajectory calculations of isotope exchange and ozone formation proceeding through O+O2 collision complexes

    Science.gov (United States)

    Baker, Thomas A.; Gellene, Gregory I.

    2002-10-01

    The isotope exchange reaction, and the three-body ozone formation rate proceeding through an ozone complex, have been studied by classical and quasi-classical trajectory techniques. The exchange rate studies indicate that the rate of this reaction is dominantly sensitive to the O+O2 entrance channel characteristics of the potential energy surface. A detailed consideration of the dynamics of the intermediate ozone complex reveals three important classes. In one class, the complex adopts an ozonelike geometry, largely undergoing asymmetric stretchinglike motion until it dissociates. In a second class, the oxygen atom and molecule never visit the ozonelike geometry but rather remain separated by relatively large distances trapped near the angular momentum barrier in the entrance channel of a pseudo-effective potential. These complexes, which cannot undergo exchange, are, nevertheless, found to contribute significantly to ozone formation at high density of the third body suggesting that the association of the high-density effective formation rate constant with twice the exchange rate may not be valid. The third class can be considered a hybrid of the first two, spending some time as an ozonelike complex and some time as a large atom-diatomic complex. This third class provides a mechanism for rearranging atom locations in the complex (e.g., end and middle position swapping) and, consequently, would not be well accounted for by statistical treatments of the ozone complex based on a single ozonelike reference geometry. In general, the survival time distributions of the complexes are found to be nonexponential. However, when the detailed survival time distributions are coupled with a Lennard-Jones collision model for the stabilization step, the experimental ozone formation rate can be adequately modeled over a broad range of temperature and density.

  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

    2017-08-28

    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( 2 S) atoms with SO 2 (X̃ 1 A ' ) molecules is presented here. For such a study, a double many-body expansion potential energy surface previously reported for HSO 2 ( 2 A) is used. This work was motivated by recent experiments by Ma et al. studying collisions of H + SO 2 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 HSO 2 ). 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 SO 2 with relatively low vibrational excitation energy, while indirect ones dominate the conversion from translational energy to high values of the vibrational counterpart.

  6. Internal energy of HCl upon photolysis of 2-chloropropene at 193 nm investigated with time-resolved Fourier-transform spectroscopy and quasiclassical trajectories

    International Nuclear Information System (INIS)

    Chang, C.-M.; Huang, Y.-H.; Liu, S.-Y.; Lee, Y.-P.; Pombar-Perez, Marta; Martinez-Nunez, Emilio; Vazquez, Saulo A.

    2008-01-01

    Following photodissociation of 2-chloropropene (H 2 CCClCH 3 ) at 193 nm, vibration-rotationally resolved emission spectra of HCl (υ≤6) in the spectral region of 1900-2900 cm -1 were recorded with a step-scan time-resolved Fourier-transform spectrometer. All vibrational levels show a small low-J component corresponding to ∼400 K and a major high-J component corresponding to 7100-18 700 K with average rotational energy of 39± 3 11 kJ mol -1 . The vibrational population of HCl is inverted at υ=2, and the average vibrational energy is 86±5 kJ mol -1 . Two possible channels of molecular elimination producing HCl+propyne or HCl+allene cannot be distinguished positively based on the observed internal energy distribution of HCl. The observed rotational distributions fit qualitatively with the distributions of both channels obtained with quasiclassical trajectories (QCTs), but the QCT calculations predict negligible populations for states at small J. The observed vibrational distribution agrees satisfactorily with the total QCT distribution obtained as a weighted sum of contributions from both four-center elimination channels. Internal energy distributions of HCl from 2-chloropropene and vinyl chloride are compared.

  7. Mode specificity in the OH + CHD3 reaction: Reduced-dimensional quantum and quasi-classical studies on an ab initio based full-dimensional potential energy surface

    International Nuclear Information System (INIS)

    Song, Hongwei; Yang, Minghui; Lu, Yunpeng; Li, Jun; Guo, Hua

    2016-01-01

    An initial state selected time-dependent wave packet method is applied to study the dynamics of the OH + CHD 3 reaction with a six-dimensional model on a newly developed full-dimensional ab initio potential energy surface (PES). This quantum dynamical (QD) study is complemented by full-dimensional quasi-classical trajectory (QCT) calculations on the same PES. The QD results indicate that both translational energy and the excitation of the CH stretching mode significantly promote the reaction while the excitation of the umbrella mode has a negligible effect on the reactivity. For this early barrier reaction, interestingly, the CH stretching mode is more effective than translational energy in promoting the reaction except at very low collision energies. These QD observations are supported by QCT results. The higher efficacy of the CH stretching model in promoting this early barrier reaction is inconsistent with the prediction of the naively extended Polanyi’s rules, but can be rationalized by the recently proposed sudden vector projection model.

  8. Management by Trajectory: Trajectory Management Study Report

    Science.gov (United States)

    Leiden, Kenneth; Atkins, Stephen; Fernandes, Alicia D.; Kaler, Curt; Bell, Alan; Kilbourne, Todd; Evans, Mark

    2017-01-01

    In order to realize the full potential of the Next Generation Air Transportation System (NextGen), improved management along planned trajectories between air navigation service providers (ANSPs) and system users (e.g., pilots and airline dispatchers) is needed. Future automation improvements and increased data communications between aircraft and ground automation would make the concept of Management by Trajectory (MBT) possible.

  9. The OH + D2 --> HOD + D angle-velocity distribution: quasi-classical trajectory calculations on the YZCL2 and WSLFH potential energy surfaces and comparison with experiments at ET = 0.28 eV.

    Science.gov (United States)

    Sierra, José Daniel; Martínez, Rodrigo; Hernando, Jordi; González, Miguel

    2009-12-28

    The angle-velocity distribution (HOD) of the OH + D(2) reaction at a relative translational energy of 0.28 eV has been calculated using the quasi-classical trajectory (QCT) method on the two most recent potential energy surfaces available (YZCL2 and WSLFH PESs), widely extending a previous investigation of our group. Comparison with the high resolution experiments of Davis and co-workers (Science, 2000, 290, 958) shows that the structures (peaks) found in the relative translational energy distributions of products could not be satisfactorily reproduced in the calculations, probably due to the classical nature of the QCT method and the importance of quantum effects. The calculations, however, worked quite well for other properties. Overall, both surfaces led to similar results, although the YZCL2 surface is more accurate to describe the H(3)O PES, as derived from comparison with high level ab initio results. The differences observed in the QCT calculations were interpreted considering the somewhat larger anisotropy of the YZCL2 PES when compared with the WSLFH PES.

  10. First order correction to quasiclassical scattering amplitude

    International Nuclear Information System (INIS)

    Kuz'menko, A.V.

    1978-01-01

    First order (with respect to h) correction to quasiclassical with the aid of scattering amplitude in nonrelativistic quantum mechanics is considered. This correction is represented by two-loop diagrams and includes the double integrals. With the aid of classical equations of motion, the sum of the contributions of the two-loop diagrams is transformed into the expression which includes one-dimensional integrals only. The specific property of the expression obtained is that the integrand does not possess any singularities in the focal points of the classical trajectory. The general formula takes much simpler form in the case of one-dimensional systems

  11. Mode specificity in the OH + CHD{sub 3} reaction: Reduced-dimensional quantum and quasi-classical studies on an ab initio based full-dimensional potential energy surface

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hongwei, E-mail: hwsong@wipm.ac.cn; Yang, Minghui [Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Lu, Yunpeng [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Li, Jun [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Guo, Hua [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2016-04-28

    An initial state selected time-dependent wave packet method is applied to study the dynamics of the OH + CHD{sub 3} reaction with a six-dimensional model on a newly developed full-dimensional ab initio potential energy surface (PES). This quantum dynamical (QD) study is complemented by full-dimensional quasi-classical trajectory (QCT) calculations on the same PES. The QD results indicate that both translational energy and the excitation of the CH stretching mode significantly promote the reaction while the excitation of the umbrella mode has a negligible effect on the reactivity. For this early barrier reaction, interestingly, the CH stretching mode is more effective than translational energy in promoting the reaction except at very low collision energies. These QD observations are supported by QCT results. The higher efficacy of the CH stretching model in promoting this early barrier reaction is inconsistent with the prediction of the naively extended Polanyi’s rules, but can be rationalized by the recently proposed sudden vector projection model.

  12. Study of particle swarm optimization particle trajectories

    CSIR Research Space (South Africa)

    Van den Bergh, F

    2006-01-01

    Full Text Available . These theoretical studies concentrate mainly on simplified PSO systems. This paper overviews current theoretical studies, and extend these studies to investigate particle trajectories for general swarms to include the influence of the inertia term. The paper also...

  13. Non-Gaussianity in a quasiclassical electronic circuit

    Science.gov (United States)

    Suzuki, Takafumi J.; Hayakawa, Hisao

    2017-05-01

    We study the non-Gaussian dynamics of a quasiclassical electronic circuit coupled to a mesoscopic conductor. Non-Gaussian noise accompanying the nonequilibrium transport through the conductor significantly modifies the stationary probability density function (PDF) of the flux in the dissipative circuit. We incorporate weak quantum fluctuation of the dissipative LC circuit with a stochastic method and evaluate the quantum correction of the stationary PDF. Furthermore, an inverse formula to infer the statistical properties of the non-Gaussian noise from the stationary PDF is derived in the classical-quantum crossover regime. The quantum correction is indispensable to correctly estimate the microscopic transfer events in the QPC with the quasiclassical inverse formula.

  14. 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

  15. On quasiclassical approximation in the inverse scattering method

    International Nuclear Information System (INIS)

    Geogdzhaev, V.V.

    1985-01-01

    Using as an example quasiclassical limits of the Korteweg-de Vries equation and nonlinear Schroedinger equation, the quasiclassical limiting variant of the inverse scattering problem method is presented. In quasiclassical approximation the inverse scattering problem for the Schroedinger equation is reduced to the classical inverse scattering problem

  16. On the derivation of quasi-classical equations for superconductors or 3He

    International Nuclear Information System (INIS)

    Shelankov, A.L.

    1984-11-01

    We present a method for the derivation of the quasi-classical equations for Keldysh Green function of a superconductor or superfluid 3 He. It is shown that Green functions on the classical trajectories g(Y 1 ,Y 2 ) which depend on two trajectory coordinates y 1 and y 2 , give the full description of the system within quasi-classical accuracy. The equation of motion for g(y 1 ,y 2 ) is obtained. it is shown that g(y)=g(y+0,y)+g(y-0,y) is equal to the Green function in momentum space integrated with respect to xi=vsub(F)(p-psub(F)). The normalization condition (g(y)) 2 =1 is proved in a direct manner using the properties of g(y 1 ,y 2 ) with y 1 not=Y 2 . The different methods of introducing the distribution function are discussed. (orig.)

  17. Branching trajectory continual integral

    International Nuclear Information System (INIS)

    Maslov, V.P.; Chebotarev, A.M.

    1980-01-01

    Heuristic definition of the Feynman continual integral over branching trajectories is suggested which makes it possible to obtain in the closed form the solution of the Cauchy problem for the model Hartree equation. A number of properties of the solution is derived from an integral representation. In particular, the quasiclassical asymptotics, exact solution in the gaussian case and perturbation theory series are described. The existence theorem for the simpliest continual integral over branching trajectories is proved [ru

  18. Quasiclassical approximation for ultralocal scalar fields

    International Nuclear Information System (INIS)

    Francisco, G.

    1984-01-01

    It is shown how to obtain the quasiclassical evolution of a class of field theories called ultralocal fields. Coherent states that follow the 'classical' orbit as defined by Klauder's weak corespondence principle and restricted action principle is explicitly shown to approximate the quantum evolutions as (h/2π) → o. (Author) [pt

  19. Study of soccer ball flight trajectory

    Directory of Open Access Journals (Sweden)

    Javorova Juliana

    2018-01-01

    Full Text Available In this paper the trajectories of a soccer ball for the most important kicks in the football game - a corner kick and a direct free kick are studied. The soccer ball is modelled as an ideal rigid hollow spherical body with six degrees of freedom, which performs a general motion in an immovable air environment with constant parameters. The ball 3D orientation is determined by the three Cardan angles. The aerodynamic forces and moments with which the air environment acts to the ball are taken into account. Two of the most dangerous areas of the football goal are defined. Differential equations which describe the motion of the soccer ball are solved numerically by MatLab-Simulink.

  20. Andreev bound states. Some quasiclassical reflections

    International Nuclear Information System (INIS)

    Lin, Y.; Leggett, A. J.

    2014-01-01

    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

  1. 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.

  2. H + H2 on LEPS and Porter-Karplus surfaces;Quasiclassical differential cross sections for reactive scattering

    International Nuclear Information System (INIS)

    Jorgensen, A.D.; Gislason, E.A.; Hillenbrand, E.A.

    1981-01-01

    The reactive differential cross section is determined by the use of a fourier sine series for the H + H 2 reaction on the Porter Karplus and LEPS surfaces. The A + BC program was used to run quasiclassical trajectories. Saddle-point properties are compared, including those for SLTH surfaces. The use of the Fourier sine series enables one to obtain very accurate differential cross sections, allowing precise comparison of the reaction dynamics on different potential energy surfaces and at different energies

  3. 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. © 2013 Elsevier Ltd. All rights reserved.

  4. Boundary conditions for quasiclassical Green's function for superfluid Fermi systems

    International Nuclear Information System (INIS)

    Nagai, K.; Hara, J.

    1988-01-01

    The authors show that the quasiclassical Green's Function for Fermi liquids can be constructed from the solutions of the Bogoliubov-de Gennes equation within the Andreev approximation and derive self-consistent relations to be satisfied by the quasiclassical Green's function at the surfaces. The so-called normalization condition for the quasiclassical Green's function is obtained from this self-consistent relation. They consider a specularly reflecting wall, a randomly rippled wall, and a proximity boundary as model surfaces. Their boundary condition for the randomly rippled wall is different from that derived by Buchholtz and Rainer and Buchholtz

  5. Gravitation in the 'quasi-classical' theory

    International Nuclear Information System (INIS)

    Wignall, J.W.G.; Zangari, M.

    1990-01-01

    The 'quasi-classical' picture of particles as extendend periodic disturbances in a classical nonlinear field, previously shown to imply all the equations of Maxwell electrodynamics with very little formal input, is here applied to the other known long-range force, gravitation. It is shown that the picture's absolute interpretation of inertial mass and four-potential as measures of the local spacing between equal-phase hypersurfaces, together with the empirically established proportionality of gravitational 'charge' to inertial mass, leads naturally to the gravitational red-shift formula, and it thus provides a physical basis for the spacetime curvature that is the central idea of Einstein's general theory of relativity. 16 refs., 1 fig

  6. Quasi-Classical Trajectory Dynamics Study of the Cl(2P) + C2H6 → HCl(v,j) + C2H5 Reaction. Comparison with Experiment.

    Science.gov (United States)

    Espinosa-Garcia, Joaquin; Martinez-Nuñez, Emilio; Rangel, Cipriano

    2018-03-15

    To understand and simulate the dynamics behavior of the title reaction, QCT calculations were performed on a recently developed global analytical potential energy surface, PES-2017. These calculations combine the classical description of the dynamics with pseudoquantization in the reactants and products to perform a theoretical/experimental comparison on the same footing. Thus, in the products a series of constraints are included to analyze the HCl(v = 0,j) product, which is experimentally detected. At collision energies of 5.5 and 6.7 kcal mol -1 the largest fraction of available energy is deposited as translation, 67%, while the ethyl radical shows significant internal energy, 27%, and so it does not act as a spectator of the reaction, thus reproducing recent experimental evidence. The HCl(v=0, j) rotational distribution is cold, peaking at j = 2, only one unit hotter than experiment, which represents an error of 0.12 kcal mol -1 . At a collision energy of 5.5 kcal mol -1 product translational distribution is slightly hotter than experiment, but at 6.7 kcal mol -1 agreement with recent experiments is practically quantitative, suggesting that the first experiments should be revised. In addition, we observe that the HCl(v=0, j) scattering distribution shifts from isotropic at low values of j to backward at high values of j, which is in agreement with experimental data. Finally, no evidence was found for the "chattering" mechanism suggested to explain the low translational energy of the HCl product in the backward scattering region. In sum, agreement with experiments of a series of sensible dynamic properties permits us to be optimistic on the quality and accuracy of the theoretical tools used in the present work, QCT and PES-2017.

  7. Quasiclassical treatment and odd-parity/triplet correspondence in topological superconductors

    International Nuclear Information System (INIS)

    Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko

    2014-01-01

    We construct a quasiclassical framework for topological superconductors with a strong spin–orbit coupling such as Cu x Bi 2 Se 3 . In a manner of the quasiclassical treatment, by decomposing the slowly varying component from a total quasiparticle wave function, the original massive Dirac Bogoliubov–de Gennes (BdG) Hamiltonian derived from a tight-binding model represented by an 8 × 8 matrix is reduced to a 4 × 4 matrix. The resultant equations are equivalent to Andreev-type equations of singlet or triplet superconductors, in which the apparent spin–orbit coupling vanishes. Using this formalism, we find that the odd-parity superconductivity in topological superconductors turns to the spin-triplet one. Moreover, in terms of quasiclassical treatment, we show that the topologically-protected zero-energy states in topological superconductors have correspond to the Andreev bound states established in a long history of studies of unconventional superconductors. This clearly indicates that low-energy nontrivial superconducting properties in the topological superconductors can be analyzed using established theoretical descriptions of the spin-triplet superconductors. (author)

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

    Science.gov (United States)

    Qi, Feng; Du, Fei

    2013-02-25

    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

  9. Superconductivity: a quasiclassical theory of multiple interface geometry

    International Nuclear Information System (INIS)

    Rameshwar, Rudra; Prashant, Sagar; Prasad, Jagdish

    2005-01-01

    In many cases of interests such as a multilayer mesoscopic structure or the grain boundaries network in high technologies, one deal with the situation where multiple interfaces should be treated simultaneously on equal footing. In this paper we have focused on theoretically concept, i.e. even an isolated interface poses certain difficulties. Since abrupt changes violate the quasiclassical condition, the standard theory of superconductivity in terms of the quasiclassical matrix Green function g R is invalid at interfaces. The interface is included via the boundary condition derived by Zaitsev a cubic matrix relation in superconductivity. (author)

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

    Science.gov (United States)

    2014-04-01

    studies that showed the possible link between positive psychological assets and health outcomes is The Nun Study .38 A group of American nuns who were...38. Danner DD, Snowdon DA, Friesen VW. Positive emotions in early life and longevity: findings from the nun study . J Pers Soc Psychol. 2000; 80...Trajectory Study PRINCIPAL INVESTIGATOR: Nansook Park CONTRACTING ORGANIZATION: University of Michigan, Ann Arbor, MI 48109

  11. Quasi-Classical Description of Heavy Ion Reactions

    International Nuclear Information System (INIS)

    Luk'yanov, V.K.

    1994-01-01

    A method for calculating the distorted waves for a realistic nuclear complex potential with the Coulomb forces included is developed using the quasi-classical and high energy approximations. The distorted waves are obtained in the analytical form and applications are made to elastic, inelastic scattering and to the one-nucleon transfer reactions. 9 refs., 2 figs

  12. Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

    Science.gov (United States)

    Jambrina, P. G.; Lara, Manuel; Menéndez, M.; Launay, J.-M.; Aoiz, F. J.

    2012-10-01

    Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S(1D) + H2 → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002), 10.1063/1.1431280] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009), 10.1021/jp903790h]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S(1D).

  13. 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

    2010-02-07

    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

  14. Quasiclassical Theory of Spin Dynamics in Superfluid ^3He: Kinetic Equations in the Bulk and Spin Response of Surface Majorana States

    Science.gov (United States)

    Silaev, M. A.

    2018-06-01

    We develop a theory based on the formalism of quasiclassical Green's functions to study the spin dynamics in superfluid ^3He. First, we derive kinetic equations for the spin-dependent distribution function in the bulk superfluid reproducing the results obtained earlier without quasiclassical approximation. Then, we consider spin dynamics near the surface of fully gapped ^3He-B-phase taking into account spin relaxation due to the transitions in the spectrum of localized fermionic states. The lifetimes of longitudinal and transverse spin waves are calculated taking into account the Fermi-liquid corrections which lead to a crucial modification of fermionic spectrum and spin responses.

  15. Communication: Symmetrical quasi-classical analysis of linear optical spectroscopy

    Science.gov (United States)

    Provazza, Justin; Coker, David F.

    2018-05-01

    The symmetrical quasi-classical approach for propagation of a many degree of freedom density matrix is explored in the context of computing linear spectra. Calculations on a simple two state model for which exact results are available suggest that the approach gives a qualitative description of peak positions, relative amplitudes, and line broadening. Short time details in the computed dipole autocorrelation function result in exaggerated tails in the spectrum.

  16. Quasiclassical deformation in KP hierarchy and Benney's long wave equations

    International Nuclear Information System (INIS)

    Kolokol'tsov, V.N.; Lebedev, D.R.

    1987-01-01

    In the paper by means of the formal variant of Zakharov-Shabat ''dressing'' method various formulas are obtained for the generating functions of the conservation laws of Kadomtsev-Petvias hierarchy which turn into analogous formulas for Benney hierarchy in the quasiclassical limit. The generating fucntion of the conservation laws of Miura type is constructed for higher Benney equations and the simple proof of the related identities is given

  17. Nonrelativistic Schroedinger equation in quasi-classical theory

    International Nuclear Information System (INIS)

    Wignall, J.W.G.

    1987-01-01

    The author has recently proposed a quasi-classical theory of particles and interactions in which particles are pictured as extended periodic disturbances in a universal field chi(x,t), interacting with each other via nonlinearity in the equation of motion for chi. The present paper explores the relationship of this theory to nonrelativistic quantum mechanics; as a first step, it is shown how it is possible to construct from chi a configuration-space wave function Psi(x 1 , X 2 , t), and that the theory requires that Psi satisfy the two-particle Schroedinger equation in the case where the two particles are well separated from each other. This suggests that the multiparticle Schroedinger equation can be obtained as a direct consequence of the quasi-classical theory without any use of the usual formalism (Hilbert space, quantization rules, etc.) of conventional quantum theory and in particular without using the classical canonical treatment of a system as a crutch theory which has subsequently to be quantized. The quasi-classical theory also suggests the existence of a preferred absolute gauge for the electromagnetic potentials

  18. Y-system and quasi-classical strings

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Nikolay [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; St. Petersburg INP, Gatchina, St. Petersburg (Russian Federation)

    2009-11-15

    Recently Kazakov, Vieira and the author conjectured the Y-system set of equations describing the planar spectrum of AdS/CFT. In this paper we solve the Y-system equations in the strong coupling scaling limit. We show that the quasi-classical spectrum of string moving inside AdS{sub 3} x S{sup 1} matches precisely with the prediction of the Y-system. Thus the Y-system, unlike the asymptotic Bethe ansatz, describes correctly the spectrum of one-loop string energies including all exponential finite size corrections. This gives a very non-trivial further support in favor of the conjecture. (orig.)

  19. Chiral magnetic effect in the presence of electroweak interactions as a quasiclassical phenomenon

    Science.gov (United States)

    Dvornikov, Maxim; Semikoz, Victor B.

    2018-03-01

    We elaborate the quasiclassical approach to obtain the modified chiral magnetic effect (CME) in the case when the massless charged fermions interact with electromagnetic fields and the background matter by the electroweak forces. The derivation of the anomalous current along the external magnetic field involves the study of the energy density evolution of chiral particles in parallel electric and magnetic fields. We consider both the particle acceleration by the external electric field and the contribution of the Adler anomaly. The condition of the validity of this method for the derivation of the CME is formulated. We obtain the expression for the electric current along the external magnetic field, which appears to coincide with our previous results based on the purely quantum approach. Our results are compared with the findings of other authors.

  20. 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

  1. Decay of the vortex tangle at zero temperature and quasiclassical turbulence

    International Nuclear Information System (INIS)

    Nemirovskii, Sergej K.

    2013-01-01

    We review and analyze a series of works, both experimental and numerical and theoretical, dealing with the decay of quantum turbulence at zero temperature. Free decay of the vortex tangle is a key argument in favor of the idea that a chaotic set of quantum vortices can mimic classical turbulence, or at least reproduce many of the basic features. The corresponding topic is referred as the quasiclassical turbulence. Appreciating significance of the challenging problem of classical turbulence it can be expressed that the idea to study it in terms of quantized line is indeed very important and may be regarded as a breakthrough. For this reason, the whole theory, together with the supporting experimental results and numerical simulations should be carefully scrutinized. One of the main arguments, supporting the idea of quasiclassical turbulence is the fact that vortex tangle decays at zero temperature, when the mutual friction is absent. Since all other possible mechanisms of dissipation of the vortex energy, discussed in literature, are related to the small scales, it is natural to suggest that the Kolmogorov cascade takes place with the flow of the energy in space of scales, just like as in the classical turbulence. In the present work we discuss an alternative mechanism of decay of the vortex tangle, which is not associated with dissipation at small scales. This mechanism is a diffusive-like spreading of the vortex tangle due to evaporation of small vortex loops. We discuss a number of experiments and numerical simulations, considering them from the point of view of alternative mechanism.

  2. Parametric Studies of Flat Plate Trajectories Using VIC and Penalization

    Directory of Open Access Journals (Sweden)

    François Morency

    2018-01-01

    Full Text Available Flying debris is generated in several situations: when a roof is exposed to a storm, when ice accretes on rotating wind turbines, or during inflight aircraft deicing. Four dimensionless parameters play a role in the motion of flying debris. The goal of the present paper is to investigate the relative importance of four dimensionless parameters: the Reynolds number, the Froude number, the Tachikawa number, and the mass moment of inertia parameters. Flying debris trajectories are computed with a fluid-solid interaction model formulated for an incompressible 2D laminar flow. The rigid moving solid effects are modelled in the Navier-Stokes equations using penalization. A VIC scheme is used to solve the flow equations. The aerodynamic forces and moments are used to compute the acceleration and the velocity of the solid. A database of 64 trajectories is built using a two-level full factorial design for the four factors. The dispersion of the plate position at a given horizontal position decreases with the Froude number. Moreover, the Tachikawa number has a significant effect on the median plate position.

  3. The radiation amplification effect in the scattering of a quasi-classical electron by an ion in an electromagnetic field of medium intensity

    International Nuclear Information System (INIS)

    Freiv, A V; Roshchupkin, S P

    2008-01-01

    The possibility of amplification of electromagnetic radiation is theoretically studied in the scattering of a quasi-classical electron by an ion in a field of linearly polarized waves of medium intensity. An expression for the total cross-section (the gain coefficient) for the wide interval of values of the adiabaticity parameter is obtained. It is shown that the wave amplification takes place in the range of values of adiabaticity parameter greater than 2 and can be sufficiently large

  4. Trajectories of health-related quality of life in children with epilepsy: a cohort study.

    Science.gov (United States)

    Ferro, Mark A; Camfield, Carol S; Levin, Simon D; Smith, Mary Lou; Wiebe, Samuel; Zou, Guangyong; Speechley, Kathy N

    2013-11-01

    Little is known about subgroups of children with epilepsy who may experience less favorable outcomes over time. The objectives of this study were to document trajectories of health-related quality of life (HRQL) and to identify predictors of the trajectory group in children with new-onset epilepsy. Data were obtained from the Health Related Quality of Life in Children with Epilepsy Study, a prospective multisite study of children 4-12 years old with new-onset epilepsy followed for 24 months. Health-related quality of life was measured using the Quality of Life in Childhood Epilepsy questionnaire. Trajectories of HRQL were investigated using latent class trajectory modeling. Multinomial logistic regression was used to identify child, parent, and family predictors of HRQL trajectories. A total of 374 families responded at baseline and 283 (76%) completed the study. Five HRQL trajectories were observed: low-increasing (4%), moderate-decreasing (12%), moderate-increasing (22%), high-increasing (32%), and high-stable (30%). Many children in the low-increasing, moderate-increasing, high-increasing, and high-stable had clinically meaningful improvements in HRQL: 82%, 47%, 63%, and 44%, respectively. In contrast, the majority of children in the moderate-decreasing group (56%) experienced clinically meaningful declines in their HRQL. Factors predicting trajectories were number of antiepileptic drugs prescribed, presence of comorbid behavior or cognitive problems, parent depression, and family functioning and demands. Results suggested that children with epilepsy are not homogenous but rather consist of groups with different trajectories and unique predictors of HRQL. Problems associated with child behavior and cognition were the strongest predictors identified. Given that several risk factors are modifiable, it is important to examine these as potential targets within a family-centered framework to improve HRQL of children with new-onset epilepsy. Wiley Periodicals, Inc.

  5. Career Trajectories of Municipal Servants: Two Types of Professional Mobility (Case Study in Novgorod Region

    Directory of Open Access Journals (Sweden)

    A A Kurakin

    2013-12-01

    Full Text Available The case study of a district in the Novgorod region shows some scenarios of recruiting new employees in the district and town municipalities, their work motivation and the most plausible career trajectories. The author argues that on the municipal level (district or its administrative center there are parallel career ladders for the top-ranked municipal clerks and for the rest of the municipal staff: the career trajectory of the high-ranked clerks can be described as a step-by-step trajectory, while the one of the lower-ranked employees — as a shuttle trajectory. There is an almost insurmountable border line between these two levels of municipal hierarchy, an obstacle for implementing the classical Weberian characteristics of “proper” bureaucracy: meritocratic recruitment and workers’ promotion and predictable long-term career ladders.

  6. Quasi-classical approaches to vibronic spectra revisited

    Science.gov (United States)

    Karsten, Sven; Ivanov, Sergei D.; Bokarev, Sergey I.; Kühn, Oliver

    2018-03-01

    The framework to approach quasi-classical dynamics in the electronic ground state is well established and is based on the Kubo-transformed time correlation function (TCF), being the most classical-like quantum TCF. Here we discuss whether the choice of the Kubo-transformed TCF as a starting point for simulating vibronic spectra is as unambiguous as it is for vibrational ones. Employing imaginary-time path integral techniques in combination with the interaction representation allowed us to formulate a method for simulating vibronic spectra in the adiabatic regime that takes nuclear quantum effects and dynamics on multiple potential energy surfaces into account. Further, a generalized quantum TCF is proposed that contains many well-established TCFs, including the Kubo one, as particular cases. Importantly, it also provides a framework to construct new quantum TCFs. Applying the developed methodology to the generalized TCF leads to a plethora of simulation protocols, which are based on the well-known TCFs as well as on new ones. Their performance is investigated on 1D anharmonic model systems at finite temperatures. It is shown that the protocols based on the new TCFs may lead to superior results with respect to those based on the common ones. The strategies to find the optimal approach are discussed.

  7. On the given accuracy distribution time for quasiclassical trajectory-coherent states

    International Nuclear Information System (INIS)

    Bagrov, V.G.; Belov, V.V.

    1988-01-01

    A notion of effective destruction time of a given exactitude of the wave equation approximate solution is introduced. It is shown that in the case of a particle moving in constant uniform magnetic field the effective destruction time of a given exactitude is comparable to the time of one turn of the particle on its orbit. For the motion in electric fields the exactitude may increase with time and its effective destruction does not take place

  8. Work functioning trajectories in cancer patients: Results from the longitudinal Work Life after Cancer (WOLICA) study.

    Science.gov (United States)

    Dorland, Heleen F; Abma, Femke I; Roelen, Corné A M; Stewart, Roy E; Amick, Benjamin C; Ranchor, Adelita V; Bültmann, Ute

    2017-11-01

    More than 60% of cancer patients are able to work after cancer diagnosis. However, little is known about their functioning at work. Therefore, the aims of this study were to (1) identify work functioning trajectories in the year following return to work (RTW) in cancer patients and (2) examine baseline sociodemographic, health-related and work-related variables associated with work functioning trajectories. This longitudinal cohort study included 384 cancer patients who have returned to work after cancer diagnosis. Work functioning was measured at baseline, 3, 6, 9 and 12 months follow-up. Latent class growth modeling (LCGM) was used to identify work functioning trajectories. Associations of baseline variables with work functioning trajectories were examined using univariate and multivariate analyses. LCGM analyses with cancer patients who completed on at least three time points the Work Role Functioning Questionnaire (n = 324) identified three work functioning trajectories: "persistently high" (16% of the sample), "moderate to high" (54%) and "persistently low" work functioning (32%). Cancer patients with persistently high work functioning had less time between diagnosis and RTW and had less often a changed meaning of work, while cancer patients with persistently low work functioning reported more baseline cognitive symptoms compared to cancer patients in the other trajectories. This knowledge has implications for cancer care and guidance of cancer patients at work. © 2017 UICC.

  9. A study of variable thrust, variable specific impulse trajectories for solar system exploration

    Science.gov (United States)

    Sakai, Tadashi

    A study has been performed to determine the advantages and disadvantages of variable thrust and variable Isp (specific impulse) trajectories for solar system exploration. There have been several numerical research efforts for variable thrust, variable Isp, power-limited trajectory optimization problems. All of these results conclude that variable thrust, variable Isp (variable specific impulse, or VSI) engines are superior to constant thrust, constant Isp (constant specific impulse; or CSI) engines. However, most of these research efforts assume a mission from Earth to Mars, and some of them further assume that these planets are circular and coplanar. Hence they still lack the generality. This research has been conducted to answer the following questions: (1) Is a VSI engine always better than a CSI engine or a high thrust engine for any mission to any planet with any time of flight considering lower propellant mass as the sole criterion? (2) If a planetary swing-by is used for a VSI trajectory, is the fuel savings of a VSI swing-by trajectory better than that of a CSI swing-by or high thrust swing-by trajectory? To support this research, an unique, new computer-based interplanetary trajectory calculation program has been created. This program utilizes a calculus of variations algorithm to perform overall optimization of thrust, Isp, and thrust vector direction along a trajectory that minimizes fuel consumption for interplanetary travel. It is assumed that the propulsion system is power-limited, and thus the compromise between thrust and Isp is a variable to be optimized along the flight path. This program is capable of optimizing not only variable thrust trajectories but also constant thrust trajectories in 3-D space using a planetary ephemeris database. It is also capable of conducting planetary swing-bys. Using this program, various Earth-originating trajectories have been investigated and the optimized results have been compared to traditional CSI and high

  10. 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.

  11. Aging-related trajectories of lung function in the general population-The Doetinchem Cohort Study.

    NARCIS (Netherlands)

    van Oostrom, Sandra H; Engelfriet, Peter M; Verschuren, W M Monique; Schipper, Maarten; Wouters, Inge M; Boezen, Marike; Smit, Henriëtte A; Kerstjens, Huib A M; Picavet, H Susan J

    2018-01-01

    The objective of this study was to explore trajectories of lung function decline with age in the general population, and to study the effect of sociodemographic and life style related risk factors, in particular smoking and BMI. For this purpose, we used data from the Doetinchem Cohort Study (DCS)

  12. Income trajectories affect treatment of dental caries from childhood to young adulthood: a birth cohort study.

    Science.gov (United States)

    Peres, Marco Aurelio; Liu, Pingzhou; Demarco, Flavio Fernando; Silva, Alexandre Emidio Ribeiro; Wehrmeister, Fernando Cesar; Menezes, Ana Maria; Peres, Karen Glazer

    2018-01-01

    We aimed to analyze the effects of family income trajectories on the increase in dental caries from childhood to young adulthood. Data from the 1993 Pelotas (Brazil) birth cohort study, in which dental caries was measured at ages 6, 12, and 18 years, were analyzed. Family income of 302 participants was assessed at birth, and at 4, 11, 15, and 18 years of age. Mother's education, toothbrushing frequency, dental visiting, dental caries in primary dentition, and birth weight were covariates. A latent class growth analysis was conducted to characterize trajectories of time-varying variables. The influence of income trajectories on the increase in dental caries from age 6 to age 18 was evaluated by a generalized linear mixed model. After adjustment, the increases in numbers of decayed and missing teeth (DMT) from age 6 to age 18 were associated with family income trajectory. The incident rate ratios (IRR) of DMT compared with the group of stable high incomes were 2.36 for stable low incomes, 1.71 for downward, and 1.64 for upward. The IRR of teeth being filled in stable low-income groups compared with stable high-income groups was 0.55. Family income mobility affected treatment patterns of dental caries. Differences across income trajectory groups were found in the components of dental caries indices rather than in the experience of disease.

  13. Quasiclassical R-matrix theory of inelastic processes in collisions of electrons with HCl molecules

    International Nuclear Information System (INIS)

    Fabrikant, I.I.

    1991-01-01

    The R-matrix theory for the vibrational excitation and dissociative attachment in e-HCl collisions is developed. Only one pole in the R-matrix expansion is included. This allows for making a connection between the R-matrix and the nonlocal-complex-potential theories, and for obtaining the expression for the dissociative-attachment cross section without using the R-matrix radius in the internuclear coordinate. All matrix elements in the equation for the vibrational-excitation and dissociative-attachment amplitudes are calculated using the quasiclassical approach. We study how the results depend on the number of vibrational levels of the neutral molecule included in the theory and show how to exclude the vibrational continuum by a modification of the nonlocal-complex potential. The results for the vibrational-excitation cross sections are extremely sensitive to the behavior of the R-matrix potential curve near the point of crossing this curve with the potential curve of the neutral molecule. Particularly in some cases the cross section at the threshold peak exhibits the boomerang oscillations earlier found for HCl by Domcke [in Aspects of Electron-Molecule Scattering and Photoionization, edited by A. Herzenberg (AIP, New Haven, 1989), p. 169]. The dissociative-attachment cross sections are in reasonable agreement with experiment and with other theories

  14. Trajectories of maternal depression and offspring psychopathology at 6 years: 2004 Pelotas cohort study

    Science.gov (United States)

    Matijasevich, Alicia; Murray, Joseph; Cooper, Peter J.; Anselmi, Luciana; Barros, Aluísio J.D.; Barros, Fernando C.; Santos, Iná S.

    2015-01-01

    Background Few studies have addressed the course and severity of maternal depression and its effects on child psychiatric disorders from a longitudinal perspective. This study aimed to identify longitudinal patterns of maternal depression and to evaluate whether distinct depression trajectories predict particular psychiatric disorders in offspring. Methods Cohort of 4231 births followed-up in the city of Pelotas, Brazil. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) at 3, 12, 24 and 48 months and 6 years after delivery. Psychiatric disorders in 6-year-old children were evaluated through the development and well-being assessment (DAWBA) instrument. Trajectories of maternal depression were calculated using a group-based modelling approach. Results We identified five trajectories of maternal depressive symptoms: a “low” trajectory (34.8%), a “moderate low” (40.9%), a “increasing” (9.0%), a “decreasing” (9.9%), and a “high-chronic” trajectory (5.4%). The probability of children having any psychiatric disorder, as well as both internalizing and externalizing problems, increased as we moved from the “low” to the “high-chronic” trajectory. These differences were not explained by maternal and child characteristics examined in multivariate analyses. Limitations Data on maternal depression at 3-months was available on only a sub-sample. In addition, we had to rely on maternal report of child’s behavior alone. Conclusions The study revealed an additive effect on child outcome of maternal depression over time. We identified a group of mothers with chronic and severe symptoms of depression throughout the first six years of the child life and for this group child psychiatric outcome was particularly compromised. PMID:25553403

  15. Cognitive Trajectory Changes Over 20 Years Before Dementia Diagnosis: A Large Cohort Study.

    Science.gov (United States)

    Li, Ge; Larson, Eric B; Shofer, Jane B; Crane, Paul K; Gibbons, Laura E; McCormick, Wayne; Bowen, James D; Thompson, Mary Lou

    2017-12-01

    Longitudinal studies have shown an increase in cognitive decline many years before clinical diagnosis of dementia. We sought to estimate changes, relative to "normal" aging, in the trajectory of scores on a global cognitive function test-the Cognitive Abilities Screening Instrument (CASI). A prospective cohort study. Community-dwelling members of a U.S. health maintenance organization. Individuals aged 65 and older who had no dementia diagnosis at baseline and had at least two visits with valid CASI test score (N = 4,315). Average longitudinal trajectories, including changes in trajectory before clinical diagnosis in those who would be diagnosed with dementia, were estimated for CASI item response theory (IRT) scores. The impact of sex, education level, and APOE genotype on cognitive trajectories was assessed. Increased cognitive decline relative to "normal" aging was evident in CASI IRT at least 10 years before clinical diagnosis. Male gender, lower education, and presence of ≥1 APOE ε4 alleles were associated with lower average IRT scores. In those who would be diagnosed with dementia, a trajectory change point was estimated at an average of 3.1 years (95% confidence interval 3.0-3.2) before clinical diagnosis, after which cognitive decline appeared to accelerate. The change point did not differ by sex, education level, or APOE ε4 genotype. There were subtle differences in trajectory slopes by sex and APOE ε4 genotype, but not by education. Decline in average global cognitive function was evident at least 10 years before clinical diagnosis of dementia. The decline accelerated about 3 years before clinical diagnosis. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  16. Management by Trajectory Trade Study of Roles and Responsibilities Between Participants and Automation Report

    Science.gov (United States)

    Fernandes, Alicia D.; Kaler, Curt; Leiden, Kenneth; Atkins, Stephen; Bell, Alan; Kilbourne, Todd; Evans, Mark

    2017-01-01

    This report describes a trade study of roles and responsibilities associated with the Management by Trajectory (MBT) concept. The MBT concept describes roles, responsibilities, and information and automation requirements for providing air traffic controllers and managers the ability to quickly generate, evaluate and implement changes to an aircraft's trajectory. In addition, the MBT concept describes mechanisms for imposing constraints on flight operator preferred trajectories only to the extent necessary to maintain safe and efficient traffic flows, and the concept provides a method for the exchange of trajectory information between ground automation systems and the aircraft that allows for trajectory synchronization and trajectory negotiation. The participant roles considered in this trade study include: airline dispatcher, flight crew, radar controller, traffic manager, and Air Traffic Control System Command Center (ATCSCC) traffic management specialists. The proposed allocation of roles and responsibilities was based on analysis of several use cases that were developed for this purpose as well as for walking through concept elements. The resulting allocation of roles and responsibilities reflects both increased automation capability to support many aviation functions, as well as increased flexibility to assign responsibilities to different participants - in many cases afforded by the increased automation capabilities. Note that the selection of participants to consider for allocation of each function is necessarily rooted in the current environment, in that MBT is envisioned as an evolution of the National Airspace System (NAS), and not a revolution. A key feature of the MBT allocations is a vision for the traffic management specialist to take on a greater role. This is facilitated by the vision that separation management functions, in addition to traffic management functions, will be carried out as trajectory management functions. This creates an opportunity

  17. 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 interindividual 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,…

  18. 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…

  19. 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

    2018-03-01

    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.

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

    Science.gov (United States)

    2013-10-01

    shifted to embrace a disease model of human nature. People are seen as flawed and fragile, casualties of cruel environments or bad genetics . Positive...research shows numerous benefits of positive thinking. Optimism has been studied extensively by psychologists, under several different rubrics

  1. Structural social relations and cognitive ageing trajectories: evidence from the Whitehall II cohort study.

    Science.gov (United States)

    Elovainio, Marko; Sommerlad, Andrew; Hakulinen, Christian; Pulkki-Råback, Laura; Virtanen, Marianna; Kivimäki, Mika; Singh-Manoux, Archana

    2017-11-07

    Social relations are important for health, particularly at older ages. We examined the salience of frequency of social contacts and marital status for cognitive ageing trajectories over 21 years, from midlife to early old age. Data are from the Whitehall II cohort study, including 4290 men and 1776 women aged 35-55 years at baseline (1985-88). Frequency of social contacts and marital status were measured in 1985-88 and 1989-90. Assessment of cognitive function on five occasions (1991-94, 1997-99, 2003-04, 2007-09 and 2012-13) included the following tests: short-term memory, inductive reasoning, verbal fluency (phonemic and semantic) and a combined global score. Cognitive trajectories over the study period were analysed using longitudinal latent growth class analyses, and the associations of these latent classes (trajectory memberships) with social relations were analysed using multinominal logistic regression. More frequent social contacts [relative risk (RRR) 0.96, 95% confidence interval (CI) 0.94 - 0.98] and being married (RRR 0.70, 95% CI 0.58 - 0.84) were associated with lower probability of being on a low rather than high cognitive performance trajectory over the subsequent 21 years. These associations persisted after adjustment for covariates. Of the sub-tests, social relations variables had the strongest association with phonemic fluency (RRR 0.95, 95% CI 0.94 - 0.97 for frequent contact; RRR 0.59, 95% CI 0.48 - 0.71 for being married). More frequent social contacts and having a spouse were associated with more favourable cognitive ageing trajectories. Further studies are needed to examine whether interventions designed to improve social connections affect cognitive ageing. © The Author 2017; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

  2. Concurrent trajectories of change in adolescent and maternal depressive symptoms in the TORDIA study.

    Science.gov (United States)

    Perloe, Alexandra; Esposito-Smythers, Christianne; Curby, Timothy W; Renshaw, Keith D

    2014-04-01

    Depression has a heightened prevalence in adolescence, with approximately 15 % of adolescents experiencing a major depressive episode by age 18. Depression in adolescence also poses a risk for future distress and impairment. Despite treatment advances, many adolescents relapse after initial remission. Family context may be an important factor in the developmental trajectory of adolescent depression, and thus in enhancing treatment. This study examined concurrent change over time in adolescent and maternal depressive symptoms in the context of the Treatment of Resistant Depression in Adolescents study. Participants were 334 adolescents (mean age: 16; SD: 1.6; 70 % female, 84 % Caucasian), and their mothers (n = 241). All adolescents were clinically depressed when they entered the study and had received previous selective serotonin reuptake inhibitor (SSRI) treatment. Adolescents received acute treatment for 12 weeks and additional treatment for 12 more weeks. Adolescent depression and suicidal ideation were assessed at 0, 6, 12, 24, 48 and 72 weeks, while maternal depressive symptoms were assessed at 0, 12, 24, 48 and 72 weeks. Latent basis growth curve analyses showed a significant correlation over 72 weeks between trajectories of maternal and adolescent depressive symptoms, supporting the hypothesis of concurrent patterns of change in these variables. The trajectories were correlated more strongly in a subsample that included only dyads in which mothers reported at least one depressive symptom at baseline. Results did not show a correlation between trajectories of maternal depressive symptoms and adolescent suicidal ideation. These findings suggest that adolescent and maternal depressive symptoms change in tandem, and that treatment for adolescent depression can benefit the wider family system. Notably, most mothers in this sample had subclinical depressive symptoms. Future research might explore these trajectories in dyads with more severely depressed mothers.

  3. 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

  4. Neighborhood Walkability and Body Mass Index Trajectories: Longitudinal Study of Canadians.

    Science.gov (United States)

    Wasfi, Rania A; Dasgupta, Kaberi; Orpana, Heather; Ross, Nancy A

    2016-05-01

    To assess the impact of neighborhood walkability on body mass index (BMI) trajectories of urban Canadians. Data are from Canada's National Population Health Survey (n = 2935; biannual assessments 1994-2006). We measured walkability with the Walk Score. We modeled body mass index (BMI, defined as weight in kilograms divided by the square of height in meters [kg/m(2)]) trajectories as a function of Walk Score and sociodemographic and behavioral covariates with growth curve models and fixed-effects regression models. In men, BMI increased annually by an average of 0.13 kg/m(2) (95% confidence interval [CI] = 0.11, 0.14) over the 12 years of follow-up. Moving to a high-walkable neighborhood (2 or more Walk Score quartiles higher) decreased BMI trajectories for men by approximately 1 kg/m(2) (95% CI = -1.16, -0.17). Moving to a low-walkable neighborhood increased BMI for men by approximately 0.45 kg/m(2) (95% CI = 0.01, 0.89). There was no detectable influence of neighborhood walkability on body weight for women. Our study of a large sample of urban Canadians followed for 12 years confirms that neighborhood walkability influences BMI trajectories for men, and may be influential in curtailing male age-related weight gain.

  5. Social adversity in pregnancy and trajectories of women's depressive symptoms: A longitudinal study.

    Science.gov (United States)

    Kingsbury, Ann M; Plotnikova, Maria; Clavarino, Alexandra; Mamun, Abullah; Najman, Jake M

    2018-02-01

    Sound evidence has linked the experience of adversity with depression. Less is known about this association over time. The aim of this study is to determine whether or not social adversity experienced by pregnant women is associated with their patterns of depressive symptoms over their reproductive life course. Data were obtained from a cohort of women collected at their first obstetrical clinic visit of an index pregnancy (time-point 1) and at a further six time-points to 27 years following the birth. Latent Class Growth Modelling was used to estimate trajectories of women's depressive symptoms over this time period. Logistic regression modelling determined the prospective association between measures of adversity in pregnancy and 27-year postpartum depression trajectories, controlling for potential confounders. Experiencing financial problems, housing problems, serious disagreements with partners and with others, and experiencing serious health problems in pregnancy were associated with membership of high and middle depression trajectories over the 27 years. Having someone close die or have a serious illness was associated with the high depression trajectory only. Younger maternal age and low family-income at first clinic visit were also associated with an increased risk of women's membership of both high and middle depression trajectories. Experiencing adversity during pregnancy predicts subsequent patterns of maternal depression over an extended period of women's reproductive life course. It is not clear whether women's experiences of adversity during pregnancy were causally associated with subsequent depression or whether there are other explanations of the observed association. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  6. Trajectories of health-related quality of life after stroke : results from a one-year prospective cohort study

    NARCIS (Netherlands)

    van Mierlo, Maria; van Heugten, Caroline; Post, Marcel W M; Hoekstra, Trynke; Visser-Meily, Anne

    2018-01-01

    PURPOSE: To identify trajectories of physical and psychosocial health-related quality of life (HRQoL) from two months to one-year post stroke and to determine the factors that are associated with trajectory membership. METHOD: Multicenter prospective cohort study in which 351 stroke patients were

  7. 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.)

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

    International Nuclear Information System (INIS)

    Corini, Cosimo

    2009-01-01

    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.)

  9. Changing Racial/Ethnic Disparities in Heavy Drinking Trajectories Through Young Adulthood: A Comparative Cohort Study.

    Science.gov (United States)

    Williams, Edwina; Mulia, Nina; Karriker-Jaffe, Katherine J; Lui, Camillia K

    2018-01-01

    There is evidence of racial/ethnic differences in the age at which young adults age out of heavy drinking. Some studies have found Black and Hispanic drinkers engage in more frequent heavy drinking than White people beyond adulthood. Yet, the alcohol-related disparities literature has produced contradictory findings on whether an age-crossover effect is evident among racial/ethnic groups; that is, whether racial/ethnic minorities' drinking levels or trajectories are lower than White people at young ages but later exceed (or crossover) those of White people. This study extends this scant literature by assessing whether racial/ethnic differences in heavy drinking have changed over time (possibly accounting for mixed findings from prior research); and tests for an age-crossover effect in heavy drinking using longitudinal data from 2 cohorts born 20 years apart. Data are from the 1979 (n = 10,963) and 1997 (n = 8,852) cohorts of the National Longitudinal Survey of Youth (NLSY). Generalized estimating equations were used to model trajectories of heavy drinking frequency from ages 17 to 31. Racial/ethnic differences were determined using sex-stratified models and 3-way interactions of race/ethnicity with age, age-squared, and cohort. Racial/ethnic differences in heavy drinking trajectories have changed over time in men and women. In the older NLSY cohort, Hispanic men and Black women surpassed White men's and women's heavy drinking frequency by age 31. This crossover was absent in the younger cohort, where trajectories of all racial-sex groups converged by age 31. Normative trajectories have changed in Hispanics and White people of both sexes, with a delay in age of peak frequency, and greater levels of heavy drinking in the younger cohort of women. Changes in heavy drinking trajectories over time suggest the need for targeted interventions during young adulthood. While disparities in young adult heavy drinking were no longer apparent in the more recent birth cohort

  10. Work-Team Implementation and Trajectories of Manufacturing Quality: A Longitudinal Field Study

    OpenAIRE

    Rajiv D. Banker; Joy M. Field; Kingshuk K. Sinha

    2001-01-01

    The study examines the sustainability of manufacturing quality improvements following the implementation of work teams on production lines. We posit that the impact on manufacturing quality, measured as the defect rate trajectory, is monotonically nonincreasing over time and may, more specifically, assume the shape of an inverted S-curve. Employing a longitudinal research design, we investigate four work teams over a 28-month period in a field setting. Each team corresponds to one of the four...

  11. 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.

  12. Project STARS (Studies on Trajectories of Adolescent Relationships and Sexuality) : A longitudinal, multidomain 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; Kunnen, Saskia; Timmerman, Greetje; 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

  13. Quasi-classical integral method for spectra calculation of symmetric central problems

    International Nuclear Information System (INIS)

    Lobashev, A.A.; Trunov, N.N.

    2000-01-01

    The new approach to the quantization quasi-classical conditions is developed. It is based on general exact properties of the wave equations and their spectra and it does not use asymptotic decompositions. The quantization conditions for the central-symmetric potentials depend only on the totality of integrals, including the classical pulse degrees. The energy level values, calculated by means of this conditions, are in good agreement with the numerical data [ru

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  15. 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

    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

  16. Education, bilingualism, and cognitive trajectories: Sacramento Area Latino Aging Study (SALSA).

    Science.gov (United States)

    Mungas, Dan; Early, Dawnté R; Glymour, M Maria; Zeki Al Hazzouri, Adina; Haan, Mary N

    2018-01-01

    This study examined the influence of education, country where education occurred, and monolingual-bilingual (English/Spanish) language usage on late life cognitive trajectories in the Sacramento Area Latino Study on Aging (SALSA), an epidemiological study of health and cognition in Hispanics, mostly of Mexican origin, age 60 and over (N = 1,499). SALSA followed a large cohort of older Latinos for up to 7 assessment waves from 1998 to 2007. Global cognition was assessed by using the Modified Mini Mental State Examination, and the Spanish English Verbal Learning Test was used to measure episodic memory. Education, country of origin, and language usage patterns were collected at the baseline assessment and used as predictors of longitudinal trajectories of cognition. Parallel process mixed effects models were used to examine effects of education and language variables on baseline cognition and rate of cognitive decline. Mixed effects longitudinal models showed that education had strong effects on baseline global cognition and verbal memory but was not related to decline over up to 9 years of longitudinal follow-up. Differences in education effects between subgroups educated in Mexico and in the United States were minor. Monolingual-bilingual language usage was not related to cognitive decline, and bilinguals did not significantly differ from monolingual English speakers on baseline cognitive scores. Hypotheses that higher education and bilingualism protect against late life cognitive decline were not supported and education effects on late-life cognitive trajectories did not substantially differ across U.S.- and Mexico-educated groups. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  17. The impact of parity on life course blood pressure trajectories: the HUNT study in Norway.

    Science.gov (United States)

    Haug, Eirin B; Horn, Julie; Markovitz, Amanda Rose; Fraser, Abigail; Macdonald-Wallis, Corrie; Tilling, Kate; Romundstad, Pål Richard; Rich-Edwards, Janet Wilson; Åsvold, Bjørn Olav

    2018-01-24

    The drop in blood pressure during pregnancy may persist postpartum, but the impact of pregnancy on blood pressure across the life course is not known. In this study we examined blood pressure trajectories for women in the years preceding and following pregnancy and compared life course trajectories of blood pressure for parous and nulliparous women. We linked information on all women who participated in the population-based, longitudinal HUNT Study, Norway with pregnancy information from the Medical Birth Registry of Norway. A total of 23,438 women were included with up to 3 blood pressure measurements per woman. Blood pressure trajectories were compared using a mixed effects linear spline model. Before first pregnancy, women who later gave birth had similar mean blood pressure to women who never gave birth. Women who delivered experienced a drop after their first birth of - 3.32 mmHg (95% CI, - 3.93, - 2.71) and - 1.98 mmHg (95% CI, - 2.43, - 1.53) in systolic and diastolic blood pressure, respectively. Subsequent pregnancies were associated with smaller reductions. These pregnancy-related reductions in blood pressure led to persistent differences in mean blood pressure, and at age 50, parous women still had lower systolic (- 1.93 mmHg; 95% CI, - 3.33, - 0.53) and diastolic (- 1.36 mmHg; 95% CI, - 2.26, - 0.46) blood pressure compared to nulliparous women. The findings suggest that the first pregnancy and, to a lesser extent, successive pregnancies are associated with lasting and clinically relevant reductions in systolic and diastolic blood pressure.

  18. Drinking and smoking patterns during pregnancy: Development of group-based trajectories in the Safe Passage Study.

    Science.gov (United States)

    Dukes, Kimberly; Tripp, Tara; Willinger, Marian; Odendaal, Hein; Elliott, Amy J; Kinney, Hannah C; Robinson, Fay; Petersen, Julie M; Raffo, Cheryl; Hereld, Dale; Groenewald, Coen; Angal, Jyoti; Hankins, Gary; Burd, Larry; Fifer, William P; Myers, Michael M; Hoffman, Howard J; Sullivan, Lisa

    2017-08-01

    Precise identification of drinking and smoking patterns during pregnancy is crucial to better understand the risk to the fetus. The purpose of this manuscript is to describe the methodological approach used to define prenatal drinking and smoking trajectories from a large prospective pregnancy cohort, and to describe maternal characteristics associated with different exposure patterns. In the Safe Passage Study, detailed information regarding quantity, frequency, and timing of exposure was self-reported up to four times during pregnancy and at 1 month post-delivery. Exposure trajectories were developed using data from 11,692 pregnancies (9912 women) where pregnancy outcome was known. Women were from three diverse populations: white (23%) and American Indian (17%) in the Northern Plains, US, and mixed ancestry (59%) in South Africa (other/not specified [1%]). Group-based trajectory modeling was used to identify 5 unique drinking trajectories (1 none/minimal, 2 quitting groups, 2 continuous groups) and 7 smoking trajectories (1 none/minimal, 2 quitting groups, 4 continuous groups). Women with pregnancies assigned to the low- or high-continuous drinking groups were less likely to have completed high school and were more likely to have enrolled in the study in the third trimester, be of mixed ancestry, or be depressed than those assigned to the none/minimal or quit-drinking groups. Results were similar when comparing continuous smokers to none/minimal and quit-smoking groups. Further, women classified as high- or low-continuous drinkers were more likely to smoke at moderate-, high-, and very high-continuous levels, as compared to women classified as non-drinkers and quitters. This is the first study of this size to utilize group-based trajectory modeling to identify unique prenatal drinking and smoking trajectories. These trajectories will be used in future analyses to determine which specific exposure patterns subsequently manifest as poor peri- and postnatal outcomes

  19. The roles of lesson study in the development of mathematics learning instrument based on learning trajectory

    Science.gov (United States)

    Misnasanti; Dien, C. A.; Azizah, F.

    2018-03-01

    This study is aimed to describe Lesson Study (LS) activity and its roles in the development of mathematics learning instruments based on Learning Trajectory (LT). This study is a narrative study of teacher’s experiences in joining LS activity. Data collecting in this study will use three methods such as observation, documentations, and deep interview. The collected data will be analyzed with Milles and Huberman’s model that consists of reduction, display, and verification. The study result shows that through LS activity, teachers know more about how students think. Teachers also can revise their mathematics learning instrument in the form of lesson plan. It means that LS activity is important to make a better learning instruments and focus on how student learn not on how teacher teach.

  20. Numerical study and ex vivo assessment of HIFU treatment time reduction through optimization of focal point trajectory

    Science.gov (United States)

    Grisey, A.; Yon, S.; Pechoux, T.; Letort, V.; Lafitte, P.

    2017-03-01

    Treatment time reduction is a key issue to expand the use of high intensity focused ultrasound (HIFU) surgery, especially for benign pathologies. This study aims at quantitatively assessing the potential reduction of the treatment time arising from moving the focal point during long pulses. In this context, the optimization of the focal point trajectory is crucial to achieve a uniform thermal dose repartition and avoid boiling. At first, a numerical optimization algorithm was used to generate efficient trajectories. Thermal conduction was simulated in 3D with a finite difference code and damages to the tissue were modeled using the thermal dose formula. Given an initial trajectory, the thermal dose field was first computed, then, making use of Pontryagin's maximum principle, the trajectory was iteratively refined. Several initial trajectories were tested. Then, an ex vivo study was conducted in order to validate the efficicency of the resulting optimized strategies. Single pulses were performed at 3MHz on fresh veal liver samples with an Echopulse and the size of each unitary lesion was assessed by cutting each sample along three orthogonal planes and measuring the dimension of the whitened area based on photographs. We propose a promising approach to significantly shorten HIFU treatment time: the numerical optimization algorithm was shown to provide a reliable insight on trajectories that can improve treatment strategies. The model must now be improved in order to take in vivo conditions into account and extensively validated.

  1. Web application for recording learners’ mouse trajectories and retrieving their study logs for data analysis

    Directory of Open Access Journals (Sweden)

    Yoshinori Miyazaki

    2012-03-01

    Full Text Available With the accelerated implementation of e-learning systems in educational institutions, it has become possible to record learners’ study logs in recent years. It must be admitted that little research has been conducted upon the analysis of the study logs that are obtained. In addition, there is no software that traces the mouse movements of learners during their learning processes, which the authors believe would enable teachers to better understand their students’ behaviors. The objective of this study is to develop a Web application that records students’ study logs, including their mouse trajectories, and to devise an IR tool that can summarize such diversified data. The results of an experiment are also scrutinized to provide an analysis of the relationship between learners’ activities and their study logs.

  2. 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.

  3. Quasi-classical derivation of the Dirac and one-particle Schroedinger equations

    International Nuclear Information System (INIS)

    Wignall, J.W.G.

    1990-08-01

    The quasi-classical approach, in which particles are regarded as extended periodic excitations of a classical nonlinear field, is for the first time applied quantitatively in the quantum domain. It is shown that the twofold intrinsic 'spin' degree of freedom possessed by an electron can be interpreted in a purely classical way, and that the Lorentz covariant incorporation of this degree of freedom requires that the spacetime evolution of an electron excitation in a prescribed external field be given by the Dirac equation and hence, in the nonrelativistic limit, by the Pauli or Schroedinger one-particle equations. 17 refs

  4. The superflow state of 3He-B at a diffusive wall. Quasiclassical calculations

    International Nuclear Information System (INIS)

    Kopnin, N.B.; Soininen, P.I.

    1992-01-01

    The authors report first computations considering effects of a rough wall on the counterflow state in superfluid 3 He-B for high flow velocities. Using the quasiclassical Green's-function formalism supplemented by the boundary conditions for a diffusive wall, they calculate the order-parameter field and the supercurrent near a container wall for various pressures and temperatures. One of the results is that the current density at the wall as a function of the flow has a maximum at the velocity which is about half of the pair breaking velocity

  5. Quantum and classical studies of collisional excitation in H + CO and two other projects in theoretical chemical dynamics

    International Nuclear Information System (INIS)

    Geiger, L.C.

    1985-01-01

    This dissertation is a collection of four projects in theoretical chemical dynamics. In the first two projects collisional excitation in H + CO was studied using the quasiclassical trajectory method and the quantum infinite order sudden approximation (QIOS). Integral cross sections calculated using these methods were found to agree well with experimental and classical IOS results. The trajectory study was also used to examine the effects of potential energy surface features on the dynamics. Two surfaces were examined: a fitted surface based on ab initio points and a global ab initio surface. Next, the quasiclassical trajectory method was used to obtain cross sections and rate constants for O + H 2 → OH + H and analogous deuterium isotope reactions. The results using the Johnson and Winter surface agreed well with those of transition state theory (TST) and experiment, except for O + HD → OH + D. TST rate constants were calculated using an ab initio surface. These results were in poor agreement with calculations using the Johnson and Winter surface. A theory of action-angle variables for coupled oscillator systems was developed in the fourth project

  6. Household Food Insecurity and Children's Behaviour Problems: New Evidence from a Trajectories-Based Study

    Science.gov (United States)

    Huang, Jin; Vaughn, Michael G.

    2016-01-01

    This study examined the association between household food insecurity (insufficient access to adequate and nutritious food) and trajectories of externalising and internalising behaviour problems in children from kindergarten to fifth grade using longitudinal data from the Early Childhood Longitudinal Study—Kindergarten Cohort (ECLS-K), a nationally representative study in the USA. Household food insecurity was assessed using the eighteen-item standard food security scale, and children's behaviour problems were reported by teachers. Latent growth curve analysis was conducted on 7,348 children in the ECLS-K, separately for boys and girls. Following adjustment for an extensive array of confounding variables, results suggest that food insecurity generally was not associated with developmental change in children's behaviour problems. The impact of food insecurity on behaviour problems may be episodic or interact with certain developmental stages. PMID:27559210

  7. Hopefulness predicts resilience after hereditary colorectal cancer genetic testing: a prospective outcome trajectories study

    Directory of Open Access Journals (Sweden)

    Chu Annie TW

    2010-06-01

    Full Text Available Abstract Background - Genetic testing for hereditary colorectal cancer (HCRC had significant psychological consequences for test recipients. This prospective longitudinal study investigated the factors that predict psychological resilience in adults undergoing genetic testing for HCRC. Methods - A longitudinal study was carried out from April 2003 to August 2006 on Hong Kong Chinese HCRC family members who were recruited and offered genetic testing by the Hereditary Gastrointestinal Cancer Registry to determine psychological outcomes after genetic testing. Self-completed questionnaires were administered immediately before (pre-disclosure baseline and 2 weeks, 4 months and 1 year after result disclosure. Using validated psychological inventories, the cognitive style of hope was measured at baseline, and the psychological distress of depression and anxiety was measured at all time points. Results - Of the 76 participating subjects, 71 individuals (43 men and 28 women; mean age 38.9 ± 9.2 years from nine FAP and 24 HNPCC families completed the study, including 39 mutated gene carriers. Four patterns of outcome trajectories were created using established norms for the specified outcome measures of depression and anxiety. These included chronic dysfunction (13% and 8.7%, recovery (0% and 4.3%, delayed dysfunction (13% and 15.9% and resilience (76.8% and 66.7%. Two logistic regression analyses were conducted using hope at baseline to predict resilience, with depression and anxiety employed as outcome indicators. Because of the small number of participants, the chronic dysfunction and delayed dysfunction groups were combined into a non-resilient group for comparison with the resilient group in all subsequent analysis. Because of low frequencies, participants exhibiting a recovery trajectory (n = 3 for anxiety and n = 0 for depression were excluded from further analysis. Both regression equations were significant. Baseline hope was a significant

  8. Hopefulness predicts resilience after hereditary colorectal cancer genetic testing: a prospective outcome trajectories study.

    Science.gov (United States)

    Ho, Samuel M Y; Ho, Judy W C; Bonanno, George A; Chu, Annie T W; Chan, Emily M S

    2010-06-11

    Genetic testing for hereditary colorectal cancer (HCRC) had significant psychological consequences for test recipients. This prospective longitudinal study investigated the factors that predict psychological resilience in adults undergoing genetic testing for HCRC. A longitudinal study was carried out from April 2003 to August 2006 on Hong Kong Chinese HCRC family members who were recruited and offered genetic testing by the Hereditary Gastrointestinal Cancer Registry to determine psychological outcomes after genetic testing. Self-completed questionnaires were administered immediately before (pre-disclosure baseline) and 2 weeks, 4 months and 1 year after result disclosure. Using validated psychological inventories, the cognitive style of hope was measured at baseline, and the psychological distress of depression and anxiety was measured at all time points. Of the 76 participating subjects, 71 individuals (43 men and 28 women; mean age 38.9 +/- 9.2 years) from nine FAP and 24 HNPCC families completed the study, including 39 mutated gene carriers. Four patterns of outcome trajectories were created using established norms for the specified outcome measures of depression and anxiety. These included chronic dysfunction (13% and 8.7%), recovery (0% and 4.3%), delayed dysfunction (13% and 15.9%) and resilience (76.8% and 66.7%). Two logistic regression analyses were conducted using hope at baseline to predict resilience, with depression and anxiety employed as outcome indicators. Because of the small number of participants, the chronic dysfunction and delayed dysfunction groups were combined into a non-resilient group for comparison with the resilient group in all subsequent analysis. Because of low frequencies, participants exhibiting a recovery trajectory (n = 3 for anxiety and n = 0 for depression) were excluded from further analysis. Both regression equations were significant. Baseline hope was a significant predictor of a resilience outcome trajectory for depression

  9. Cohort Study of ECG Left Ventricular Hypertrophy Trajectories: Ethnic Disparities, Associations With Cardiovascular Outcomes, and Clinical Utility.

    Science.gov (United States)

    Iribarren, Carlos; Round, Alfred D; Lu, Meng; Okin, Peter M; McNulty, Edward J

    2017-10-05

    ECG left ventricular hypertrophy (LVH) is a well-known predictor of cardiovascular disease. However, no prior study has characterized patterns of presence/absence of ECG LVH ("ECG LVH trajectories") across the adult lifespan in both sexes and across ethnicities. We examined: (1) correlates of ECG LVH trajectories; (2) the association of ECG LVH trajectories with incident coronary heart disease, transient ischemic attack, ischemic stroke, hemorrhagic stroke, and heart failure; and (3) reclassification of cardiovascular disease risk using ECG LVH trajectories. We performed a cohort study among 75 412 men and 107 954 women in the Northern California Kaiser Permanente Medical Care Program who had available longitudinal exposures of ECG LVH and covariates, followed for a median of 4.8 (range ECG LVH was measured by Cornell voltage-duration product. Adverse trajectories of ECG LVH (persistent, new development, or variable pattern) were more common among blacks and Native American men and were independently related to incident cardiovascular disease with hazard ratios ranging from 1.2 for ECG LVH variable pattern and transient ischemic attack in women to 2.8 for persistent ECG LVH and heart failure in men. ECG LVH trajectories reclassified 4% and 7% of men and women with intermediate coronary heart disease risk, respectively. ECG LVH trajectories were significant indicators of coronary heart disease, stroke, and heart failure risk, independently of level and change in cardiovascular disease risk factors, and may have clinical utility. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  10. Early life socioeconomic determinants of dietary score and pattern trajectories across six waves of the Longitudinal Study of Australian Children.

    Science.gov (United States)

    Gasser, Constantine E; Mensah, Fiona K; Kerr, Jessica A; Wake, Melissa

    2017-12-01

    Social patterning of dietary-related diseases may partly be explained by population disparities in children's diets. This study aimed to determine which early life socioeconomic factors best predict dietary trajectories across childhood. For waves 2-6 of the Baby (B) Cohort (ages 2-3 to 10-11 years) and waves 1-6 of the Kindergarten (K) Cohort (ages 4-5 to 14-15 years) of the Longitudinal Study of Australian Children, we constructed trajectories of dietary scores and of empirically derived dietary patterns. Dietary scores, based on the Australian Dietary Guidelines, summed children's consumption frequencies of seven groups of foods or drinks over the last 24 hours. Dietary patterns at each wave were derived using factor analyses of 12-16 food or drink items. Using multinomial logistic regression analyses, we examined associations of baseline single (parental education, remoteness area, parental employment, income, food security and home ownership) and composite (socioeconomic position and neighbourhood disadvantage) factors with adherence to dietary trajectories. All dietary trajectory outcomes across both cohorts showed profound gradients by composite socioeconomic position but not by neighbourhood disadvantage. For example, odds for children in the lowest relative to highest socioeconomic position quintile being in the 'never healthy' relative to the 'always healthy' score trajectory were OR=16.40, 95% CI 9.40 to 28.61 (B Cohort). Among the single variables, only parental education consistently predicted dietary trajectories. Child dietary trajectories vary profoundly by family socioeconomic position. If causal, reducing dietary inequities may require researching underlying pathways, tackling socioeconomic inequities and targeting health promoting interventions to less educated families. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise

  11. 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.

  12. 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

  13. 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. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

  14. 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

  15. 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 interindividual 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. Multigroup 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.

  16. Group-based developmental BMI trajectories, polycystic ovary syndrome, and gestational diabetes: a community-based longitudinal study.

    Science.gov (United States)

    Kakoly, Nadira Sultana; Earnest, Arul; Moran, Lisa J; Teede, Helena J; Joham, Anju E

    2017-11-06

    Obesity is common in young women, increasing insulin resistance (IR) and worsening pregnancy complications, including gestational diabetes (GDM). Women with polycystic ovary syndrome (PCOS) are commonly obese, which aggravates the severity of PCOS clinical expression. Relationships between these common insulin-resistant conditions, however, remain unclear. We conducted a secondary analysis of the Australian Longitudinal Study on Women's Health (ALSWH) database, including data from 8009 women aged 18-36 years across six surveys. We used latent-curve growth modelling to identify distinct body mass index (BMI) trajectories and multinomial logistic regression to explore sociodemographic and health variables characterizing BMI group membership. Logistic regression was used to assess independent risk of GDM. A total of 662 women (8.29%, 95% CI 7.68-8.89) reported PCOS. Three distinct BMI trajectories emerged, namely low stable (LSG) (63.8%), defined as an average trajectory remaining at ~25 kg/m 2 ; moderately rising (MRG) (28.8%), a curvilinear trajectory commencing in a healthy BMI and terminating in the overweight range; and high-rising (HRG) (7.4%), a curvilinear trajectory starting and terminating in the obese range. A high BMI in early reproductive life predicted membership in higher trajectories. The HRG BMI trajectory was independently associated with GDM (OR 2.50, 95% CI 1.80-3.48) and was a stronger correlate than PCOS (OR 1.89, 95% CI 1.41-2.54), maternal age, socioeconomic status, or parity. Our results suggest heterogeneity in BMI change among Australian women of reproductive age, with and without PCOS. Reducing early adult life weight represents an ideal opportunity to intervene at an early stage of reproductive life and decreases the risk of long-term metabolic complications such as GDM.

  17. Impact of childhood asthma on growth trajectories in early adolescence: Findings from the Childhood Asthma Prevention Study (CAPS).

    Science.gov (United States)

    Movin, Maria; Garden, Frances L; Protudjer, Jennifer L P; Ullemar, Vilhelmina; Svensdotter, Frida; Andersson, David; Kruse, Andreas; Cowell, Chris T; Toelle, Brett G; Marks, Guy B; Almqvist, Catarina

    2017-04-01

    Understanding the associations between childhood asthma and growth in early adolescence by accounting for the heterogeneity of growth during puberty has been largely unexplored. The objective was to identify sex-specific classes of growth trajectories during early adolescence, using a method which takes the heterogeneity of growth into account and to evaluate the association between childhood asthma and different classes of growth trajectories in adolescence. Our longitudinal study included participants with a family history of asthma born during 1997-1999 in Sydney, Australia. Hence, all participants were at high risk for asthma. Asthma status was ascertained at 8 years of age using data from questionnaires and lung function tests. Growth trajectories between 11 and 14 years of age were classified using a latent basis growth mixture model. Multinomial regression analyses were used to evaluate the association between asthma and the categorized classes of growth trajectories. In total, 316 participants (51.6% boys), representing 51.3% of the entire cohort, were included. Sex-specific classes of growth trajectories were defined. Among boys, asthma was not associated with the classes of growth trajectories. Girls with asthma were more likely than girls without asthma to belong to a class with later growth (OR: 3.79, 95% CI: 1.33, 10.84). Excluding participants using inhaled corticosteroids or adjusting for confounders did not significantly change the results for either sex. We identified sex-specific heterogeneous classes of growth using growth mixture modelling. Associations between childhood asthma and different classes of growth trajectories were found for girls only. © 2016 Asian Pacific Society of Respirology.

  18. Ultra-processed food consumption and adiposity trajectories in a Brazilian cohort of adolescents: ELANA study.

    Science.gov (United States)

    Cunha, Diana Barbosa; da Costa, Teresa Helena Macedo; da Veiga, Gloria Valeria; Pereira, Rosangela Alves; Sichieri, Rosely

    2018-05-25

    In Brazil, the increase in obesity rates has been accompanied by increased consumption of ultra-processed food (UPF). The objective of this paper was to evaluate body mass index (BMI) and body fat percentage (%BF) trajectories in adolescents over a 3-year follow-up according to the frequency of UPF consumption. Data of three consecutive years (2010, 2011, and 2012) were obtained from the Adolescent Nutritional Assessment Longitudinal Study (ELANA) that aimed to assess changes in anthropometric indicators of nutritional status, and 1035 adolescents enrolled in the 1st year of high school from six schools (four private and two public) in the metropolitan area of Rio de Janeiro, Brazil were included. At three follow-ups, they had their weights and heights measured. Body composition was measured at the first and second follow-ups. Mixed linear regression models were used to estimate BMI and %BF trajectories based on quartiles of UPF intake, adjusting for type of school, sex, physical activity, and underreporting. Compared to their counterparts in the 1st quartile, adolescents in the 4th quartile of UPF consumption had a lower daily intake of fruits, cooked vegetables, and raw vegetables and a higher intake of total sugar and physical activity levels (p < 0.001). There was an inverse association between UPF consumption and BMI both at baseline and at follow-up. Values for %BF followed the same trend. Adolescents in the 4th quartile had the greatest level of physical activity and lowest total energy intake. This study confirmed that greater intake of UPF is a marker of an unhealthy diet, but did not support the hypothesis of a high rate of change in BMI associated with greater UPF consumption, even after adjusting for physical activity.

  19. Trajectory Calculations for Bergman Cyclization Predict H/D Kinetic Isotope Effects Due to Nonstatistical Dynamics in the Product.

    Science.gov (United States)

    Doubleday, Charles; Boguslav, Mayla; Howell, Caronae; Korotkin, Scott D; Shaked, David

    2016-06-22

    An unusual H/D kinetic isotope effect (KIE) is described, in which isotopic selectivity arises primarily from nonstatistical dynamics in the product. In DFT-based quasiclassical trajectories of Bergman cyclization of (Z)-3-hexen-1,5-diyne (1) at 470 K, the new CC bond retains its energy, and 28% of nascent p-benzyne recrosses back to the enediyne on a vibrational time scale. The competing process of intramolecular vibrational redistribution (IVR) in p-benzyne is too slow to prevent this. Deuteration increases the rate of IVR, which decreases the fraction of recrossing and increases the yield of statistical (trapable) p-benzyne, 2. Trapable yields for three isotopomers of 2 range from 72% to 86%. The resulting KIEs for Bergman cyclization differ substantially from KIEs predicted by transition state theory, which suggests that IVR in this reaction can be studied by conventional KIEs. Leakage of vibrational zero point energy (ZPE) into the reaction coordinate was probed by trajectories in which initial ZPE in the CH/CD stretching modes was reduced by 25%. This did not change the predicted KIEs.

  20. Trajectory calculation of a trapped particle in electro-dynamic balance for study of chemical reaction of aerosol particles

    International Nuclear Information System (INIS)

    Okuma, Miho; Itou, Takahiro; Harano, Azuchi; Takarada, Takayuki; James, Davis E

    2013-01-01

    Electrodynamic balance (EDB) is a powerful tool for investigating the chemical reactions between a fine particle and gaseous species. But the EDB device alone is inadequate to match the rapid weight change of a fine particle caused by chemical reactions, because it takes a few seconds to set a fine particle at null point. The particle trajectory calculation for the trapped particle added to the EDB is thus a very useful tool for the measurement of the transient response of a particle weight change with no need to adjust the applied DC voltage to set the null point. The purpose of this study is to develop the trajectory calculation method to track the particle oscillation pattern in the EDB and examine the possibility for kinetic studies on the reaction of a single aerosol particle with gaseous species. The results demonstrated the feasibility of applying particle trajectory calculation to realize the research purpose.

  1. Protocol for a prospective longitudinal study investigating the participation and educational trajectories of Australian students with autism

    Science.gov (United States)

    Roberts, Jacqueline Margaret Anne; Adams, Dawn; Heussler, Helen; Keen, Deborah; Paynter, Jessica; Trembath, David; Westerveld, Marleen; Williams, Katrina

    2018-01-01

    Introduction Autism is associated with high cost to individuals, families, communities and government. Understanding educational and participation trajectories during the school years, and factors influencing these, is fundamental to reducing financial and personal costs. The primary aim of this study is to document the trajectories of Australian students with autism during their education. The secondary aim is to examine personal (eg, student skills) and environmental (eg, school setting) factors associated with differing trajectories and outcomes. Methods and analysis The cross-sequential longitudinal study will recruit two cohorts of 120 parents/caregivers of children with autism. Cohort 1 aged between 4 and 5 years and cohort 2 between 9 and 10 years to start the study. Information will be gathered from parents, teachers and school principals at six annual time points (T1 to T6). Parents will be emailed a link to an online initial questionnaire (T1) and then contacted annually and asked to complete either an extended questionnaire (T3, T5 and T6) or an abbreviated questionnaire (T2, T4). Where consent is given, the child’s current school will be contacted annually (T1 to T6) and teacher and school principal asked to complete questionnaires about the child and school. Parent and school questionnaires are comprised of questions about demographic and school factors that could influence trajectories and a battery of developmental and behavioural assessment tools designed to assess educational and participation trajectories and outcomes. Surveys will provide longitudinal data on educational and participation trajectories for children and adolescents with autism. In addition cross-sectional comparisons (within or between age groups) at each time point and cohort effects will be explored. Ethics and dissemination Ethics approvals have been granted for this study by all recruiting sites and universities in the project. Study findings will inform policy and practice

  2. Interplanetary Trajectory Design for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

    Science.gov (United States)

    Merrill, Raymond Gabriel; Qu, Min; Vavrina, Matthew A.; Englander, Jacob A.; Jones, Christopher A.

    2014-01-01

    This paper presents mission performance analysis methods and results for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger NEA. It details the optimization and design of heliocentric low-thrust trajectories to asteroid targets for the ARRM solar electric propulsion spacecraft. Extensive searches were conducted to determine asteroid targets with large pick-up mass potential and potential observation opportunities. Interplanetary trajectory approximations were developed in method based tools for Itokawa, Bennu, 1999 JU3, and 2008 EV5 and were validated by end-to-end integrated trajectories.

  3. 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…

  4. Uniqueness of global quasi-classical solutions of the Cauchy problems for first-order nonlinear partial differential equations

    International Nuclear Information System (INIS)

    Tran Duc Van

    1994-01-01

    The notion of global quasi-classical solutions of the Cauchy problems for first-order nonlinear partial differential equations is presented, some uniqueness theorems and a stability result are established by the method based on the theory of differential inclusions. In particular, the answer to an open problem of S.N. Kruzhkov is given. (author). 10 refs, 1 fig

  5. Orthogonal polynomials, Laguerre Fock space, and quasi-classical asymptotics

    Science.gov (United States)

    Engliš, Miroslav; Ali, S. Twareque

    2015-07-01

    Continuing our earlier investigation of the Hermite case [S. T. Ali and M. Engliš, J. Math. Phys. 55, 042102 (2014)], we study an unorthodox variant of the Berezin-Toeplitz quantization scheme associated with Laguerre polynomials. In particular, we describe a "Laguerre analogue" of the classical Fock (Segal-Bargmann) space and the relevant semi-classical asymptotics of its Toeplitz operators; the former actually turns out to coincide with the Hilbert space appearing in the construction of the well-known Barut-Girardello coherent states. Further extension to the case of Legendre polynomials is likewise discussed.

  6. Mapping technological trajectories as patent citation networks : a study on the history of fuel cell research

    NARCIS (Netherlands)

    Verspagen, B.

    2005-01-01

    Technological change is argued to be taking place along ordered and selective patterns, shaped jointly by technological and scientific principles, and economic and other societal factors. Historical, descriptive analysis is often used to analyze these "trajectories". Recently, quantitative methods

  7. Mapping technological trajectories as patent citation networks : a study on the history of fuel cell research

    NARCIS (Netherlands)

    Verspagen, B.

    2007-01-01

    Technological change is argued to be taking place along ordered and selective patterns, shaped jointly by technological and scientific principles, and economic and other societal factors. Historical, descriptive analysis is often used to analyze these "trajectories". Recently, quantitative methods

  8. The Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) study.

    Science.gov (United States)

    Paul, Ian M; Williams, Jennifer S; Anzman-Frasca, Stephanie; Beiler, Jessica S; Makova, Kateryna D; Marini, Michele E; Hess, Lindsey B; Rzucidlo, Susan E; Verdiglione, Nicole; Mindell, Jodi A; Birch, Leann L

    2014-07-18

    Because early life growth has long-lasting metabolic and behavioral consequences, intervention during this period of developmental plasticity may alter long-term obesity risk. While modifiable factors during infancy have been identified, until recently, preventive interventions had not been tested. The Intervention Nurses Starting Infants Growing on Healthy Trajectories (INSIGHT). Study is a longitudinal, randomized, controlled trial evaluating a responsive parenting intervention designed for the primary prevention of obesity. This "parenting" intervention is being compared with a home safety control among first-born infants and their parents. INSIGHT's central hypothesis is that responsive parenting and specifically responsive feeding promotes self-regulation and shared parent-child responsibility for feeding, reducing subsequent risk for overeating and overweight. 316 first-time mothers and their full-term newborns were enrolled from one maternity ward. Two weeks following delivery, dyads were randomly assigned to the "parenting" or "safety" groups. Subsequently, research nurses conduct study visits for both groups consisting of home visits at infant age 3-4, 16, 28, and 40 weeks, followed by annual clinic-based visits at 1, 2, and 3 years. Both groups receive intervention components framed around four behavior states: Sleeping, Fussy, Alert and Calm, and Drowsy. The main study outcome is BMI z-score at age 3 years; additional outcomes include those related to patterns of infant weight gain, infant sleep hygiene and duration, maternal responsiveness and soothing strategies for infant/toddler distress and fussiness, maternal feeding style and infant dietary content and physical activity. Maternal outcomes related to weight status, diet, mental health, and parenting sense of competence are being collected. Infant temperament will be explored as a moderator of parenting effects, and blood is collected to obtain genetic predictors of weight status. Finally, second

  9. Behavioral problem trajectories and self-esteem changes in relation with adolescent depressive symptoms: a longitudinal study.

    Science.gov (United States)

    Leung, Cherry Y; Leung, Gabriel M; Schooling, C Mary

    2018-07-01

    Prospectively childhood behavioral problems and low self-esteem are associated with depression. However, these mental health changes over time have never been examined. This study assessed the association of childhood behavioral trajectories and self-esteem changes over time with adolescent depressive symptoms. Parent-reported Rutter behavioral assessments and self-reported Culture-Free Self-Esteem Inventories (SEI) were obtained via record linkage from the Student Health Service, Department of Health (Hong Kong), and the Patient Health Questionnaire-9 (PHQ-9) depressive symptom scores were obtained via active follow-up of the Hong Kong's Children of 1997" Chinese birth cohort. Partitional clustering was used to generate homogenous trajectories between ~ 7 and ~ 11 years for Rutter scores. Changes in low self-esteem between ~ 10 and ~ 12 years were obtained from the SEI. Multiple linear regression was used to estimate their associations with depressive symptom scores at ~ 13 years. Four trajectories/groups (stable low, declining, rising, and stable high) of Rutter score and self-esteem groups were created. The stable low behavioral trajectory was associated with the fewest depressive symptoms while the stable high trajectory had 1.23 more depressive symptoms [95% confidence interval (CI) 0.84 to 1.61] than the stable low trajectory. Consistently low self-esteem (stable low) was associated with 2.96 more depressive symptoms (95% CI 2.35-3.57) compared to consistently high self-esteem (stable high). Sustained or worsening childhood behavioral problems and low self-esteem were precursors of adolescent depressive symptoms, and as such could be an early indicator of the need for intervention.

  10. Trajectory Browser Website

    Science.gov (United States)

    Foster, Cyrus; Jaroux, Belgacem A.

    2012-01-01

    The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center to be used for the preliminary assessment of trajectories to small-bodies and planets and for providing relevant launch date, time-of-flight and V requirements. The site hosts a database of transfer trajectories from Earth to asteroids and planets 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. 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 as soon as development is complete.

  11. Trajectories of Heroin Addiction: Growth Mixture Modeling Results Based on a 33-Year Follow-Up Study

    Science.gov (United States)

    Hser, Yih-Ing; Huang, David; Chou, Chih-Ping; Anglin, M. Douglas

    2007-01-01

    This study investigates trajectories of heroin use and subsequent consequences in a sample of 471 male heroin addicts who were admitted to the California Civil Addict Program in 1964-1965 and followed over 33 years. Applying a two-part growth mixture modeling strategy to heroin use level during the first 16 years of the addiction careers since…

  12. Adatom Bond Dissociation in the Collision Between an Adsorbed Atom and Incident Diatomic Molecule: A Classical Trajectory Study

    International Nuclear Information System (INIS)

    Bayhan, U.

    2004-01-01

    The collisional dissociation of the Atom-Surface bond in the diatomic molecule (gas) / atom (ads) collision taking place on a bcc-structure surface have been studied by classical trajectory methods over the collision energy ranges and the attractive well depth of the diatomic molecule (gas) / atom (ads) interactions

  13. Adverse Childhood Experiences and Blood Pressure Trajectories From Childhood to Young Adulthood The Georgia Stress and Heart Study

    NARCIS (Netherlands)

    Su, Shaoyong; Wang, Xiaoling; Pollock, Jennifer S.; Treiber, Frank A.; Xu, Xiaojing; Snieder, Harold; McCall, W. Vaughn; Stefanek, Michael; Harshfield, Gregory A.

    2015-01-01

    Background-The purposes of this study were to assess the long-term effect of adverse childhood experiences (ACEs) on blood pressure (BP) trajectories from childhood to young adulthood and to examine whether this relation is explained by childhood socioeconomic status (SES) or risk behaviors that are

  14. Trajectories of Symptoms and Impairment for Pediatric Patients with Functional Abdominal Pain: A 5-Year Longitudinal Study

    Science.gov (United States)

    Mulvaney, Shelagh; Lambert, E. Warren; Garber, Judy; Walker, Lynn S.

    2006-01-01

    Objective: This prospective study characterizes trajectories of symptoms and impairment in pediatric patients with abdominal pain not associated with identifiable organic disease. Method: The Children's Somatization Inventory and the Functional Disability Inventory were administered four times over 5 years to 132 patients (6-18 years old) seen in…

  15. Socioeconomic differences in children’s television viewing trajectory: A population-based prospective cohort study

    Science.gov (United States)

    van Grieken, Amy; Moll, Henriëtte A.; Jaddoe, Vincent W. V.; Wijtzes, Anne I.; Raat, Hein

    2017-01-01

    We aimed to evaluate the association between family socioeconomic status and repeatedly measured child television viewing time from early childhood to the school period. We analyzed data on 3,561 Dutch children from the Generation R Study, a population-based study in the Netherlands. Parent-reported television viewing time for children aged 2, 3, 4, 6 and 9 years were collected by questionnaires sent from April 2004 until January 2015. Odds ratios of watching television ≥1 hour/day at each age were calculated for children of mothers with low, mid-low, mid-high and high (reference group) education and children from low, middle and high (reference group) income households. A generalized logistic mixed model was used to assess the association between family socioeconomic status and child television viewing time trajectory. The percentage of children watching television ≥1 hour/day increased from age 2 to 9 years for all children (24.2%-85.0% for children of low-educated mothers; 4.7%-61.4% for children of high-educated mothers; 17.2%-74.9% for children from low income households; 6.2%-65.1% for children from high income households). Independent socioeconomic effect in child television viewing time was found for maternal educational level. The interaction between net household income and child age in longitudinal analyses was significant (p = 0.01), indicating that the television viewing time trajectories were different in household income subgroups. However the interaction between maternal educational level and child age was not significant (p = 0.19). Inverse socioeconomic gradients in child television viewing time were found from the preschool period to the late school period. The educational differences between the various educational subgroups remained stable with increasing age, but the differences between household income groups changed over time. Intervention developers and healthcare practitioners need to raise awareness among non-highly educated parents

  16. Socioeconomic differences in children's television viewing trajectory: A population-based prospective cohort study.

    Science.gov (United States)

    Yang-Huang, Junwen; van Grieken, Amy; Moll, Henriëtte A; Jaddoe, Vincent W V; Wijtzes, Anne I; Raat, Hein

    2017-01-01

    We aimed to evaluate the association between family socioeconomic status and repeatedly measured child television viewing time from early childhood to the school period. We analyzed data on 3,561 Dutch children from the Generation R Study, a population-based study in the Netherlands. Parent-reported television viewing time for children aged 2, 3, 4, 6 and 9 years were collected by questionnaires sent from April 2004 until January 2015. Odds ratios of watching television ≥1 hour/day at each age were calculated for children of mothers with low, mid-low, mid-high and high (reference group) education and children from low, middle and high (reference group) income households. A generalized logistic mixed model was used to assess the association between family socioeconomic status and child television viewing time trajectory. The percentage of children watching television ≥1 hour/day increased from age 2 to 9 years for all children (24.2%-85.0% for children of low-educated mothers; 4.7%-61.4% for children of high-educated mothers; 17.2%-74.9% for children from low income households; 6.2%-65.1% for children from high income households). Independent socioeconomic effect in child television viewing time was found for maternal educational level. The interaction between net household income and child age in longitudinal analyses was significant (p = 0.01), indicating that the television viewing time trajectories were different in household income subgroups. However the interaction between maternal educational level and child age was not significant (p = 0.19). Inverse socioeconomic gradients in child television viewing time were found from the preschool period to the late school period. The educational differences between the various educational subgroups remained stable with increasing age, but the differences between household income groups changed over time. Intervention developers and healthcare practitioners need to raise awareness among non-highly educated parents

  17. 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.

  18. Study of 4 trajectories of the DNTE. A pedagogic view of the 4 trajectories studied within the frame of the National Debate on Energy Transition

    International Nuclear Information System (INIS)

    Grandjean, Alain; Blanchet, Emmanuel; Finidori, Esther

    2014-02-01

    The objective of this report is, while giving explicit explanations of key variables of the scenarios, to propose a clear and pedagogic analysis of public political measures and of their impact, as well as envisaged technologies for the four trajectories of energy transition defined within the frame of the French National Debate on Energy Transition (DBTE). After a presentation of these four trajectories (DEC for high demand and electricity-based de-carbonation, DIV for average demand and vector diversity, EFF for energy efficiency and vector diversification, and SOB for energy saving and phasing out nuclear), and a presentation of the analysis methodology, a chapter analyses the underlying differences between these scenarios in terms of innovation and standard of living, of final energy consumption, of geography, of development of heat pumps, and of air and sea transport. Technical corrections applied to scenarios are also described. Then, the report proposes a comparative analysis of the evolution of energy demand per sector (housing, office building, transports, industry, agriculture) according to the four different scenarios, a comparative analysis of the evolution of energy production per vector (electricity, gas networks, heat networks, biomass) with an assessment in terms of primary energy, a discussion of issues related to research, innovation and development of technologies, and a discussion of the evolution of consumptions of fossil energies and renewable energies, of the share of renewable energies in final consumption, and of the level of greenhouse gas emissions. The last part discusses some lessons learned from this comparative analysis. Other interesting scenarios (Negatep, Ancre Div, Ademe, Negawatt) are presented in appendix, as well as some graphical representations of the developed analysis

  19. Transfer matrix in the quasiclassical approximation with constant and position-dependent mass, resonant tunneling

    International Nuclear Information System (INIS)

    Perez-Alvarez, R.; Rodriguez-Coppola, H.; Lopez-Gondar, J.; Izquierdo, M.L.

    1987-11-01

    We develop the quasiclassical approximation for the effective Hamiltonians describing nonhomogeneous systems and we deduce the wave function, the applicability conditions and the connection rules around the turning points. Based on the transfer matrix (TM) formalism we obtain expressions for the transmission coefficient of multiple barriers, the energy levels of multiple wells and the quasistationary levels of a well open by one, and by the two sides. The dispersion relation of a periodic potential profile with variable mass problem is also given. We discuss resonant tunneling for a system of multiple barriers. The transmission coefficient of such a barrier is maximum at energies close to the levels of the inner well when the end barriers are high enough and symmetric. (author). 20 refs, 1 fig

  20. Long range trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Allen, P. W.; Jessup, E. A.; White, R. E. [Air Resources Field Research Office, Las Vegas, Nevada (United States)

    1967-07-01

    results of that study, and in particular, information that may help to evaluate the significance of a trajectory endpoint, whether it is predicted, reconstructed from wind data, or obtained from a single tracer. (author)

  1. 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.

  2. Trajectory of sleep disturbances in patients undergoing lung cancer surgery: a prospective study.

    Science.gov (United States)

    Halle, Ingrid Helene; Westgaard, Therese Krystad; Wahba, Alexander; Oksholm, Trine; Rustøen, Tone; Gjeilo, Kari Hanne

    2017-08-01

    Patients with lung cancer report sleep difficulties to be frequent and bothersome symptoms. This study describes the trajectory of sleep from before and up to 12 months after surgery for lung cancer. Further, it investigates possible associations between sleep disturbance, demographic and clinical characteristics before surgery. This study is part of a longitudinal multicentre study. Sleep disturbance was measured by The General Sleep Disturbance Scale (GSDS) that investigates frequencies of sleep difficulties (21 items) and a total sum score ≥43 indicates a clinically meaningful level of sleep disturbance (score range 0-147). Linear mixed models were used to study changes in sleep from baseline to 1, 5, 9 and 12 months after surgery. The percentage of patients (n = 264) reporting sleep disturbances was 60.9% at baseline, 68.5% at Month 1, 55.4% at Month 5, 51.3% at Month 9 and 49.7% at Month 12. The increase to and decrease from Month 1 was the only significant alteration in the occurrence of sleep disturbance. The patients reported most problems within the subscales sleep quantity, early awakenings and sleep quality. Factors associated with sleep disturbance were lower age, use of pain medication and psychotropic medication and higher comorbidity score. Lung cancer patients sleep poorly, before as well as after surgery. There is a need to address sleeping disturbance routinely in clinical practice and screening for sleeping problems is indicated. Further studies are warranted concerning factors that contribute to sleep disturbance and how they best can be treated. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  3. Study of talcum charging status in parallel plate electrostatic separator based on particle trajectory analysis

    Science.gov (United States)

    Yunxiao, CAO; Zhiqiang, WANG; Jinjun, WANG; Guofeng, LI

    2018-05-01

    Electrostatic separation has been extensively used in mineral processing, and has the potential to separate gangue minerals from raw talcum ore. As for electrostatic separation, the particle charging status is one of important influence factors. To describe the talcum particle charging status in a parallel plate electrostatic separator accurately, this paper proposes a modern images processing method. Based on the actual trajectories obtained from sequence images of particle movement and the analysis of physical forces applied on a charged particle, a numerical model is built, which could calculate the charge-to-mass ratios represented as the charging status of particle and simulate the particle trajectories. The simulated trajectories agree well with the experimental results obtained by images processing. In addition, chemical composition analysis is employed to reveal the relationship between ferrum gangue mineral content and charge-to-mass ratios. Research results show that the proposed method is effective for describing the particle charging status in electrostatic separation.

  4. Trajectory parameterization-A new approach to the study of the cosmic ray penumbra

    International Nuclear Information System (INIS)

    Cooke, D.J.

    1982-01-01

    A new approach to the examination of the structure of the cosmic ray penumbra has been developed, which, while utilizing the speed, efficiency and ''real'' geomagnetic field modeling capabilities of the digital computer, yields an analytical insight equivalent to that of the earlier and elegant approaches of Stormer, and of Lemaitre and Vallarta. The method involves an assigning of parameters to trajectory features in order to allow the structure and properties of the penumbra to be systematically related to trajectory configuration by means of an automated set of computer procedures. Initial use of this ''trajectory parameterization'' technique to explore the form and stability of the penumbra has yielded new and important knowledge of the penumbra and its phenomenology. Among the new findings is the discovery of isolated forbidden penumbral ''islands.''

  5. Trajectories and the influencing factors of behavior problems in preschool children: a longitudinal study in Guangzhou, China.

    Science.gov (United States)

    Bao, Peng; Jing, Jin; Jin, Yu; Hu, Xumin; Liu, Buyun; Hu, Min

    2016-06-01

    Since child mental health problem was a global health issue, many researchers in western countries has focused on the trajectory of it to provide evidence for prevention programs. We designed this study to determine the trajectories of children's behavior problems, and to explore the effect of parent predictors on children's behavior problems in Guangzhou, China. Children (N = 1480) for this longitudinal, population-based survey, were recruited from eight regular kindergartens (October, 2010) across four districts in Guangzhou. Repeated measurement design analysis was used to compare the variation in behavioral problems by gender, only child status, and temperament. Logistic regression was applied to analyze the effect of parents' risks (maternal depression, parenting style) on the change in child problem behaviors. The scores of behavior problems (externalizing, emotional, social communication problems) were stable during the entire preschool period by gender and child number. Children with difficult temperament exhibited more problem behaviors than children with easy temperament in the early years, and the misbehaviors declined significantly over time. Moreover, maternal depression and the increase in excessive interference/over protective or punishing parenting strategies resulted in an increase in child behavior problems. There was no difference between the only-child status and child with siblings in the trajectory of problem behaviors. Parent factors were significant predictions of trajectory of child behavior problem during preschool age.

  6. Longitudinal Study of Headache Trajectories in the Year After Mild Traumatic Brain Injury: Relation to Posttraumatic Stress Disorder Symptoms.

    Science.gov (United States)

    Sawyer, Kathryn; Bell, Kathleen R; Ehde, Dawn M; Temkin, Nancy; Dikmen, Sureyya; Williams, Rhonda M; Dillworth, Tiara; Hoffman, Jeanne M

    2015-11-01

    To examine headache trajectories among persons with mild traumatic brain injury (MTBI) in the year after injury and the relation of headache trajectory to posttraumatic stress disorder (PTSD) at 1 year postinjury. Prospective, longitudinal study. Participants were recruited through a university medical center and participated in follow-up assessments by telephone. Prospectively enrolled individuals (N=212) within 1 week of MTBI who were hospitalized for observation or other system injuries. Participants were assessed at baseline and 3, 6, and 12 months postinjury. Not applicable. Participants rated average headache pain intensity using the 0 to 10 numerical rating scale at each assessment period. The PTSD Checklist-Civilian Version was completed at 12 months postinjury. Latent class growth analysis produced a 4-trajectory group model, with groups labeled resolved, worsening, improving, and chronic. Multivariate regression modeling revealed that younger age and premorbid headache correlated with membership in the worse trajectory groups (worsening and chronic; PHeadache is common in the year after MTBI, with younger people, persons who previously had headaches, and persons with PTSD more likely to report chronic or worsening headache. Further research is needed to examine whether PTSD symptoms exacerbate headaches or whether problematic headache symptoms exacerbate PTSD. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  7. 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.

    Science.gov (United States)

    Tielemans, Susanne M A J; Geleijnse, Johanna M; Menotti, Alessandro; Boshuizen, Hendriek C; Soedamah-Muthu, Sabita S; Jacobs, David R; Blackburn, Henry; Kromhout, Daan

    2015-03-09

    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 examined their association with cardiovascular mortality, all-cause mortality, and life years lost. Data from 2 prospective and nearly extinct cohorts of middle-aged men—the Minnesota Business and Professional Men Study (n=261) and the Zutphen Study (n=632)—were used. BP was measured annually during 1947-1957 in Minnesota and 1960-1970 in Zutphen. BP trajectories were identified by latent mixture modeling. Cox proportional hazards and linear regression models examined BP trajectories with cardiovascular mortality, all-cause mortality, and life years lost. Associations were adjusted for age, serum cholesterol, smoking, and diabetes mellitus. Mean initial age was about 50 years in both cohorts. After 10 years of BP measurements, men were followed until death on average 20 years later. All Minnesota men and 98% of Zutphen men died. Four BP trajectories were identified, in which mean systolic BP increased by 5 to 49 mm Hg in Minnesota and 5 to 20 mm Hg in Zutphen between age 50 and 60. The third systolic BP trajectories were associated with 2 to 4 times higher cardiovascular mortality risk, 2 times higher all-cause mortality risk, and 4 to 8 life years lost, compared to the first trajectory. Ten-year BP trajectories were the strongest predictors, among different BP measures, of cardiovascular mortality, all-cause mortality, and life years lost in Minnesota. However, average BP was the strongest predictor in Zutphen. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  8. Trajectories of Verbal Episodic Memory in Middle-Aged and Older Adults: Evidence from the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Olaya, Beatriz; Bobak, Martin; Haro, Josep Maria; Demakakos, Panayotes

    2017-06-01

    To identify distinct latent groups of baseline levels and age-related decline in verbal episodic memory in middle-aged and older adults, and to identify factors associated with these trajectories. Longitudinal study of six data collections over a period of 10 years. Population-based cohort in England. 9,515 community-dwelling adults aged 50-79 years. Six repeated measurements of immediate and delayed recall of 10 words over 10-year follow-up. Group-based trajectory modeling was used to identify patterns of baseline levels and subsequent decline in memory in two age categories (50-64 and 65-79 years), and to investigate associations between trajectories and baseline predictors of group membership (gender, education, household wealth, marital status, smoking and physical activity) and time-varying covariates (depressive symptoms and number of chronic conditions). Four trajectories were identified and labelled according to baseline status and decline in memory: very low/decline (9.8%), low/stable (40.2%), average/stable (39.5%) and good/stable (10.5%) in the younger group, and very low/rapid decline (15.7%), low/decline (32.0%), average/stable (38.8%), and good/stable (13.5%) in older participants. In people with stable or declining trajectories, a higher number of depressive symptoms and the presence of cardiovascular diseases were associated with worse memory. Female sex, younger age, and higher education, wealth and physical activity were consistently associated with more favourable trajectories. We identified four memory trajectories. Factors known to be associated with cognitive reserve (such as education, wealth and physical activity) were associated with better memory function while depressive symptoms and cardiovascular disease were associated with poorer memory. This suggests that interventions to reduce depressive symptoms and better manage cardiovascular risk factors and disease in midlife may help prevent or delay future memory decline. © 2017, Copyright

  9. 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…

  10. Evaluating management risks using landscape trajectory analysis: a case study of California fisher

    Science.gov (United States)

    Craig M. Thompson; William J. Zielinski; Kathryn L. Purcell

    2011-01-01

    Ecosystem management requires an understanding of how landscapes vary in space and time, how this variation can be affected by management decisions or stochastic events, and the potential consequences for species. Landscape trajectory analysis, coupled with a basic knowledge of species habitat selection, offers a straightforward approach to ecological risk analysis and...

  11. 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.

    2014-01-01

    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…

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

    NARCIS (Netherlands)

    Choukas-Bradley, S.; Giletta, M.; Widman, L.; Cohen, G.L.; Prinstein, M.J.

    2014-01-01

    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

  13. Tutorship and Academic Trajectories in School: Comparative Study in Two Public Universities in Mexico

    Science.gov (United States)

    Rodríguez, Emma Leticia Canales; Robelo, Octaviano García

    2015-01-01

    This work reports on the results of research on modalities of mentoring in the area of social sciences at two Mexican universities and their relationship with the academic trajectories of their students. The analysis focuses on the need to identify influences of different mentoring forms on students' academic performance. The theoretical…

  14. 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…

  15. 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

  16. Sexual risk behaviour trajectories among men who have sex with menat risk for HIV in Amsterdam, the Netherlands: a 10 year follow-up study.

    NARCIS (Netherlands)

    Basten, Maartje; Heijne, Janneke Cornelia Maria; Geskus, Ronald; Daas, Chantal Den; Kretzschmar, Mirjam; Matser, Amy

    2018-01-01

    Sexual risk behaviour changes during a person's life course. Insights in sexual risk behaviour trajectories of MSM may provide starting points for the timing of HIV prevention methods. We aimed to study longitudinal trajectories of sexual risk behaviour predictive of HIV acquisition from sexual

  17. 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

  18. Studying precipitation recycling over the Tibetan Plateau using evaporation-tagging and back-trajectory analysis

    Science.gov (United States)

    Gao, Y.

    2017-12-01

    Regional precipitation recycling (i.e., the contribution of local evaporation to local precipitation) is an important component of water cycle over the Tibetan Plateau (TP). Two methods were used to investigate regional precipitation recycling: 1) tracking of tagged atmospheric water parcels originating from evaporation in a source region (i.e., E-tagging), and 2) back-trajectory approach to track the evaporative sources contributed to precipitation in a specific region. These two methods were applied to Weather Research and Forecasting (WRF) regional climate simulations to quantify the precipitation recycling ratio in the TP for three selected years: climatologically normal, dry and wet year. The simulation region is characterized by high average elevation above 4000 m and complex terrain. The back-trajectory approach is also calculated over three sub-regions over the TP: namely western, northeastern and southeastern TP, and the E-tagging approach could provide recycling-ratio distributions over the whole TP. Three aspects are investigated to characterize the precipitation recycling: annual mean, seasonal variations and spatial distributions. Averaged over the TP, the precipitation recycling ratio estimated by the E-tagging approach is higher than that from the back-trajectory method. The back-trajectory approach uses a precipitation threshold as total precipitation in five days divided by a random number, and this number was set to 500 as a tread off between equilibrium and computational efficiency. Lower recycling ratio derived from the back-trajectory approach is related to the precipitation threshold used. The E-tagging, however, tracks every air parcel of evaporation regardless of the precipitation amount. There is no obvious seasonal variation in the recycling ratio using both methods. The E-tagging approach shows high recycling ratios in the center TP, indicating stronger land-atmospheric interactions than elsewhere.

  19. Latent trajectories of internalizing symptoms from preschool to school age: A multi-informant study in a high-risk sample.

    Science.gov (United States)

    Klein, Annette M; Schlesier-Michel, Andrea; Otto, Yvonne; White, Lars O; Andreas, Anna; Sierau, Susan; Bergmann, Sarah; Perren, Sonja; von Klitzing, Kai

    2018-04-29

    Recent proposals suggest early adversity sets in motion particularly chronic and neurobiologically distinct trajectories of internalizing symptoms. However, few prospective studies in high-risk samples delineate distinct trajectories of internalizing symptoms from preschool age onward. We examined trajectories in a high-risk cohort, oversampled for internalizing symptoms, several preschool risk/maintenance factors, and school-age outcomes. Parents of 325 children completed the Strengths and Difficulties Questionnaire on up to four waves of data collection from preschool (3-5 years) to school age (8-9 years) and Preschool Age Psychiatric Assessment interviews at both ages. Multi-informant data were collected on risk factors and symptoms. Growth mixture modelling identified four trajectory classes of internalizing symptoms with stable low, rising low-to-moderate, stable moderate, and stable high symptoms. Children in the stable high symptom trajectory manifested clinically relevant internalizing symptoms, mainly diagnosed with anxiety disorders/depression at preschool and school age. Trajectories differed regarding loss/separation experience, maltreatment, maternal psychopathology, temperament, and stress-hormone regulation with loss/separation, temperament, maternal psychopathology, and stress-hormone regulation (trend) significantly contributing to explained variance. At school age, trajectories continued to differ on symptoms, disorders, and impairment. Our study is among the first to show that severe early adversity may trigger a chronic and neurobiologically distinct internalizing trajectory from preschool age onward.

  20. 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.

  1. Is it possible to interpret in a quasiclassical way the Coulomb interaction by the exchange of virtual photon

    International Nuclear Information System (INIS)

    Federighi, T.

    1978-01-01

    By supposing that virtual photons are ''bound'' photons continuosly emitted and reabsorbed by any electron, the existence of the Coulomb's law between charges is deduced in a quasiclassical way. There are both a lower limit for the law ( approximately 10 -13 cm) originated by the cutting-off of the Bose-Einstein statistics and an upper limit ( approximately 10 17 cm) connected with the existence of a not null rest mass of the photon ( approximately 5.7.10 -56 g)

  2. TrajGraph: A Graph-Based Visual Analytics Approach to Studying Urban Network Centralities Using Taxi Trajectory Data.

    Science.gov (United States)

    Huang, Xiaoke; Zhao, Ye; Yang, Jing; Zhang, Chong; Ma, Chao; Ye, Xinyue

    2016-01-01

    We propose TrajGraph, a new visual analytics method, for studying urban mobility patterns by integrating graph modeling and visual analysis with taxi trajectory data. A special graph is created to store and manifest real traffic information recorded by taxi trajectories over city streets. It conveys urban transportation dynamics which can be discovered by applying graph analysis algorithms. To support interactive, multiscale visual analytics, a graph partitioning algorithm is applied to create region-level graphs which have smaller size than the original street-level graph. Graph centralities, including Pagerank and betweenness, are computed to characterize the time-varying importance of different urban regions. The centralities are visualized by three coordinated views including a node-link graph view, a map view and a temporal information view. Users can interactively examine the importance of streets to discover and assess city traffic patterns. We have implemented a fully working prototype of this approach and evaluated it using massive taxi trajectories of Shenzhen, China. TrajGraph's capability in revealing the importance of city streets was evaluated by comparing the calculated centralities with the subjective evaluations from a group of drivers in Shenzhen. Feedback from a domain expert was collected. The effectiveness of the visual interface was evaluated through a formal user study. We also present several examples and a case study to demonstrate the usefulness of TrajGraph in urban transportation analysis.

  3. Quantum and quasi-classical collisional dynamics of O{sub 2}–Ar at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ulusoy, Inga S. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Center for Computational and Molecular Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 (United States); Andrienko, Daniil A.; Boyd, Iain D. [Nonequilibrium Gas and Plasma Dynamics Laboratory, Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109-2140 (United States); Hernandez, Rigoberto, E-mail: hernandez@gatech.edu [Center for Computational and Molecular Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 (United States)

    2016-06-21

    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.

  4. Latent Trajectories of Trauma Symptoms and Resilience: The 3-Year Longitudinal Prospective USPER Study of Danish Veterans Deployed in Afghanistan

    DEFF Research Database (Denmark)

    Andersen, Søren B.; Karstoft, K. I.; Bertelsen, Mette

    2014-01-01

    Checklist (PCL) at 6 occasions from predeployment to 2.5 years postdeployment (study sample = 561). Predeployment vulnerabilities and deployment and postdeployment stressors were also assessed. Results: Six trajectories were identified: a resilient trajectory with low symptom levels across all assessments...... also found. Symptom fluctuation was predicted independently by predeployment risk factors (depression [OR = 1.27; 95% CI, 1.16-1.39], neuroticism [OR = 1.10; 95% CI, 1.00-1.21], and earlier traumas [OR = 1.09; 95% CI, 1.03-1.16]) and deployment-related stressors (danger/injury exposure [OR = 1.20; 95......% CI, 1.04-1.40]), but not by postdeployment stressors. Discussion: The results confirm earlier findings of stress response heterogeneity following military deployment and highlight the impact of predeployment, perideployment, and postdeployment risk factors in predicting PTSD symptomatology and late...

  5. 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.

  6. 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

  7. Albumin, Hemoglobin, and the Trajectory of Cognitive Function in Community-Dwelling Older Japanese: A 13-Year Longitudinal Study.

    Science.gov (United States)

    Murayama, H; Shinkai, S; Nishi, M; Taniguchi, Y; Amano, H; Seino, S; Yokoyama, Y; Yoshida, H; Fujiwara, Y; Ito, H

    2017-01-01

    Cognitive function can substantially decline over a long period, and understanding the trajectory of cognitive function is important. However, little is known about the linkage between nutritional biomarkers and long-term cognitive change. We analyzed 13-year longitudinal data for older Japanese to examine the associations of serum albumin and hemoglobin levels with the trajectory of cognitive function. Longitudinal study. Community-based. A total of 1,744 community-dwelling adults aged 65 years or older who participated in annual health examinations in Kusatsu town, Gunma Prefecture, Japan, from 2002-2014. Cognitive function was assessed annually by the Mini-Mental State Examination (MMSE). Albumin and hemoglobin levels at baseline (the year when a respondent first participated in the health examination) were divided into quartiles. Hierarchical linear modeling was used to analyze intrapersonal and interpersonal differences in cognitive function. Participants' MMSE scores decreased at an accelerated rate over the 13-year period. Participants with the lowest baseline albumin level (below the first quartile line) showed a greater accelerated decline in MMSE scores over time, compared with those with the highest level (above the third quartile line). Moreover, MMSE scores in participants with a lower hemoglobin level and lower MMSE score at baseline tended to decline faster over time at an accelerated rate. These findings yield new insights about the complex and diverse roles of these nutritional biomarkers on the trajectory of cognitive function in old age.

  8. Trajectories of neighborhood poverty and associations with subclinical atherosclerosis and associated risk factors: the multi-ethnic study of atherosclerosis.

    Science.gov (United States)

    Murray, Emily T; Diez Roux, Ana V; Carnethon, Mercedes; Lutsey, Pamela L; Ni, Hanyu; O'Meara, Ellen S

    2010-05-15

    The authors used data from the Multi-Ethnic Study of Atherosclerosis and latent trajectory class modeling to determine patterns of neighborhood poverty over 20 years (1980-2000 residential history questionnaires were geocoded and linked to US Census data). Using these patterns, the authors examined 1) whether trajectories of neighborhood poverty were associated with differences in the amount of subclinical atherosclerosis (common carotid intimal-media thickness) and 2) associated risk factors (body mass index, hypertension, diabetes, current smoking) at baseline (January 2000-August 2002). The authors found evidence of 5 stable trajectory groups with differing levels of neighborhood poverty ( approximately 6%, 12%, 20%, 30%, and 45%) and 1 group with 29% poverty in 1980 and approximately 11% in 2000. Mostly for women, higher cumulative neighborhood poverty was generally significantly associated with worse cardiovascular outcomes. Trends generally persisted after adjustment for adulthood socioeconomic position and race/ethnicity, although they were no longer statistically significant. Among women who had moved during the 20 years, the long-term measure had stronger associations with outcomes (except smoking) than a single, contemporaneous measure. Results indicate that cumulative 20-year exposure to neighborhood poverty is associated with greater cardiovascular risk for women. In residentially mobile populations, single-point-in-time measures underestimate long-term effects.

  9. 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 women. 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.

  10. 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 den Eijnden, Regina; Vanwesenbeeck, Wilhelmina; Kunnen, Saskia; Timmerman, Greetje; van Geert, Paul; Deković, 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

  11. 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

  12. 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

  13. Factors impacting the illness trajectory of post-infectious fatigue syndrome: a qualitative study of adults' experiences.

    Science.gov (United States)

    Stormorken, Eva; Jason, Leonard A; Kirkevold, Marit

    2017-12-13

    Post-infectious fatigue syndrome (PIFS), also known as post-viral fatigue syndrome, is a complex condition resulting in physical, cognitive, emotional, neurological, vocational and/or role performance disabilities in varying degrees that changes over time. The needs for health care resources are high, and costly, as is the economic burden on the affected individuals. Many factors may impact the trajectory, and frequently PIFS develops into a chronic condition. Health professionals lack understanding and knowledge, which results in delayed diagnosis, lack of recognition, appropriate treatment, support and practical help. The aim of our study was to explore, from the perspective of persons who had lived with PIFS for four years following an outbreak of Giardia l. induced enteritis, factors that may have impacted their illness trajectory and how these factors had played a role during different phases. In this retrospective exploratory qualitative study a group of 26 affected adults between 26 and 59 years old were selected for in-depth interviews. A maximum variation sample was recruited from a physician-diagnosed cohort of persons with PIFS enrolled at a tertiary outpatient fatigue clinic. The interviews were audio-recorded, transcribed verbatim and subjected to qualitative content analysis. Unhelpful and helpful factors were associated with the healthcare system, health professionals and the affected persons were experienced as having an impact on the trajectory. External impacting factors which are related to the health care system, providers and the social security system are misdiagnosis, trivialization of symptoms, unhelpful advice, delayed diagnosis and lack of appropriate help. Internal impacting factors related to the affected individuals were lack of knowledge, overestimating functional capacity, assuming the condition will pass, ignoring body signals and denial. A model of impacting factors in each phase of the trajectory is presented. Unmet needs may

  14. Quasiclassical approach to the weak levitation of extended states in the quantum Hall effect

    International Nuclear Information System (INIS)

    Fogler, M.M.

    1998-01-01

    The two-dimensional motion of a charged particle in a random potential and a transverse magnetic field is believed to be delocalized only at discrete energies E N . In strong fields there is a small positive deviation of E N from the center of the Nth Landau level, which is referred to as the open-quotes weak levitationclose quotes of the extended state. I calculate the size of the weak levitation effect for the case of a smooth random potential rederiving earlier results of Haldane and Yang [Phys. Rev. Lett. 78, 298 (1997)] and extending their approach to lower magnetic fields. I find that as the magnetic field decreases, this effect remains weak down to the lowest field B min where such a quasiclassical approach is still justified. Moreover, in the immediate vicinity of B min the weak levitation becomes additionally suppressed. This indicates that the open-quotes strong levitationclose quotes expected at yet even lower magnetic fields must be of a completely different origin. copyright 1998 The American Physical Society

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

    Directory of Open Access Journals (Sweden)

    Yuri V. Kovchegov

    2016-02-01

    Full Text Available 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. Quasiclassical treatment of the Auger effect in slow ion-atom collisions

    Science.gov (United States)

    Frémont, F.

    2017-09-01

    A quasiclassical model based on the resolution of Hamilton equations of motion is used to get evidence for Auger electron emission following double-electron capture in 150-keV N e10 ++He collisions. Electron-electron interaction is taken into account during the collision by using pure Coulombic potential. To make sure that the helium target is stable before the collision, phenomenological potentials for the electron-nucleus interactions that simulate the Heisenberg principle are included in addition to the Coulombic potential. First, single- and double-electron captures are determined and compared with previous experiments and theories. Then, integration time evolution is calculated for autoionizing and nonautoionizing double capture. In contrast with single capture, the number of electrons originating from autoionization slowly increases with integration time. A fit of the calculated cross sections by means of an exponential function indicates that the average lifetime is 4.4 ×10-3a .u . , in very good agreement with the average lifetime deduced from experiments and a classical model introduced to calculate individual angular momentum distributions. The present calculation demonstrates the ability of classical models to treat the Auger effect, which is a pure quantum effect.

  17. Disability Trajectories Before and After Stroke and Myocardial Infarction: The Cardiovascular Health Study.

    Science.gov (United States)

    Dhamoon, Mandip S; Longstreth, W T; Bartz, Traci M; Kaplan, Robert C; Elkind, Mitchell S V

    2017-12-01

    = .04) more than tripled after stroke (0.15 additional points per year; 95% CI, 0.004 to 0.30; P = .04). The annual increase in disability before MI (0.04 points per year; 95% CI, 0.004 to 0.08; P = .03) did not change significantly after MI (0.02 additional points per year; 95% CI, -0.07 to 0.11; P = .69). In this large, population-based study, a trajectory of increasing disability became significantly steeper after stroke but not after MI. Thus, in addition to the acute brain injury and consequent impairment, ischemic stroke may also be associated with potentially treatable long-term adverse effects on the brain that lead to accelerated functional decline.

  18. 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.

  19. Prenatal exposure to disaster-related traumatic stress and developmental trajectories of temperament in early childhood: Superstorm Sandy pregnancy study.

    Science.gov (United States)

    Zhang, Wei; Rajendran, Khushmand; Ham, Jacob; Finik, Jackie; Buthmann, Jessica; Davey, Kei; Pehme, Patricia M; Dana, Kathryn; Pritchett, Alexandra; Laws, Holly; Nomura, Yoko

    2018-07-01

    Little is known about the impact of prenatal maternal stress (PNMS) on the developmental trajectory of temperament and few studies have been able to incorporate a natural disaster as a quasi-experimental stressor. The current study investigated PNMS related to Superstorm Sandy ('Sandy'), a hurricane that struck the New York metropolitan area in October 2012, in terms of objective exposure during pregnancy, subjective stress reaction as assessed by maternal symptoms of post-traumatic stress, and their impact on the developmental changes in temperament during early childhood. A subsample of 318 mother-child dyads was drawn from the Stress in Pregnancy Study. Temperament was measured at 6, 12, 18, and 24 months of age. Objective exposure was associated with greater High-Intensity Pleasure, Approach, Perceptual Sensitivity and Fearfulness, but lower Cuddliness and Duration of Orientation at 6 months. Objective exposure and its interaction with subjective stress reaction predicted developmental changes in temperament. In particular, objective exposure was linked to greater increases in Activity Level but decreases in High-Intensity Pleasure, Approach, and Fearfulness. The combination of objective exposure and subjective stress reaction was also associated with greater increases in Activity Level. Temperament was measured solely via maternal report. Trimester-specific effects of Sandy on temperament were not examined. This is the first study to examine the effects of prenatal maternal exposure to a natural disaster on trajectories of early childhood temperament. Findings suggest that both objective stress exposure and subjective stress reaction in-utero predict developmental trajectories of temperament in early childhood. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Trajectories of health-related quality of life during the natural history of dementia: a six-wave longitudinal study.

    Science.gov (United States)

    Yu, Hongmei; Gao, Caihong; Zhang, Yanbo; He, Runlian; Zhou, Liye; Liang, Ruifeng

    2017-09-01

    The objective of this study was to explore profiles of quality of life (QoL) trajectories during the natural history of dementia and individual variations contributing to QoL trajectories. We conducted a longitudinal community-based study of 520 elderly people with mild cognitive impairment and 100 healthy people aged 60 years or over. We conducted six waves of assessment between October 2010 and May 2013 in Taiyuan, mainland China. Cognitively normal, mild cognitive impairment, global impairment, and Alzheimer's disease (AD) were defined as state 1, 2, 3, and 4, respectively. We assessed health-related QoL (HRQoL) via the Quality of Life-Alzheimer's Disease (QoL-AD) Chinese version. We used the latent growth curve model (LGCM) to investigate change in HRQoL over time. Latent growth curve model analysis revealed a mean initial QoL level of 29.865 with substantial variation and a significant mean slope for the whole sample. Multigroup LGCM showed substantial variations across individuals in initial QoL levels for each cognitive state transition group. For the slope factor, we found significant changes and variations for the transition from state 2 to 3 and from state 3 to 4. We estimated mean QoL levels over six assessments based on intercept, slope, and factor loadings for the whole sample and the three cognitive state transition groups. A decline in subjective QoL is not inevitable during the natural history of dementia in community settings, and there is a degree of individual variation in QoL. Future studies should investigate the factors associated with individual variations in QoL trajectories in AD. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Systolic Blood Pressure Trajectory, Frailty, and All-Cause Mortality >80 Years of Age: Cohort Study Using Electronic Health Records.

    Science.gov (United States)

    Ravindrarajah, Rathi; Hazra, Nisha C; Hamada, Shota; Charlton, Judith; Jackson, Stephen H D; Dregan, Alex; Gulliford, Martin C

    2017-06-13

    Clinical trials show benefit from lowering systolic blood pressure (SBP) in people ≥80 years of age, but nonrandomized epidemiological studies suggest lower SBP may be associated with higher mortality. This study aimed to evaluate associations of SBP with all-cause mortality by frailty category >80 years of age and to evaluate SBP trajectories before death. A population-based cohort study was conducted using electronic health records of 144 403 participants ≥80 years of age registered with family practices in the United Kingdom from 2001 to 2014. Participants were followed for ≤5 years. Clinical records of SBP were analyzed. Frailty status was classified using the e-Frailty Index into the categories of fit, mild, moderate, and severe. All-cause mortality was evaluated by frailty status and mean SBP in Cox proportional-hazards models. SBP trajectories were evaluated using person months as observations, with mean SBP and antihypertensive treatment status estimated for each person month. Fractional polynomial models were used to estimate SBP trajectories over 5 years before death. During follow-up, 51 808 deaths occurred. Mortality rates increased with frailty level and were greatest at SBP mortality was 7.7 per 100 person years at SBP 120 to 139 mm Hg, 15.2 at SBP 110 to 119 mm Hg, and 22.7 at SBP mortality may be accounted for by reverse causation if participants with lower blood pressure values are closer, on average, to the end of life. © 2017 The Authors.

  2. Interpreting Early Career Trajectories

    Science.gov (United States)

    Barnatt, Joan; Gahlsdorf Terrell, Dianna; D'Souza, Lisa Andries; Jong, Cindy; Cochran-Smith, Marilyn; Viesca, Kara Mitchell; Gleeson, Ann Marie; McQuillan, Patrick; Shakman, Karen

    2017-01-01

    Career decisions of four teachers are explored through the concept of figured worlds in this qualitative, longitudinal case study. Participants were purposefully chosen for similarity at entry, with a range of career trajectories over time. Teacher career paths included remaining in one school, repeated changes in schools, attrition after…

  3. Trajectory structures and transport

    International Nuclear Information System (INIS)

    Vlad, Madalina; Spineanu, Florin

    2004-01-01

    The special problem of transport in two-dimensional divergence-free stochastic velocity fields is studied by developing a statistical approach, the nested subensemble method. The nonlinear process of trapping determined by such fields generates trajectory structures whose statistical characteristics are determined. These structures strongly influence the transport

  4. 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

  5. Labour market trajectories following sickness absence due to self-reported all cause morbidity-a longitudinal study

    DEFF Research Database (Denmark)

    Pedersen, Pernille; Lund, Thomas; Lindholdt, Louise

    2016-01-01

    BACKGROUND: To investigate differences in return to work (RTW) and employment trajectories in individuals on sick leave for either mental health reasons or other health related reasons. METHODS: This study was based on 2036 new sickness absence cases who completed a questionnaire on social charac...... compared to employees on sick leave due to other health reasons. The difference could be explained by their lower RTW expectations at baseline. This emphasises the need to develop suitable and specific interventions to facilitate RTW for this group of sickness absentees....

  6. Study on the effect of sink moving trajectory on wireless sensor networks

    Science.gov (United States)

    Zhong, Peijun; Ruan, Feng

    2018-03-01

    Wireless sensor networks are developing very fast in recent years, due to their wide potential applications. However there exists the so-called hot spot problem, namely the nodes close to static sink node tend to die earlier than other nodes since they have heavier burden to forward. The introduction of mobile sink node can effectively alleviate this problem since sink node can move along certain trajectories, causing hot spot nodes more evenly distributed. In this paper, we make extensive experimental simulations for circular sensor network, with one mobile sink moving along different radius circumference. The whole network is divided into several clusters and there is one cluster head (CH) inside each cluster. The ordinary sensors communicate with CH and CHs construct a chain until the sink node. Simulation results show that the best network performance appears when sink moves along 0.25 R in terms of network lifetime.

  7. 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.

  8. Sleep Problem Trajectories and Well-Being in Children with Attention-Deficit Hyperactivity Disorder: A Prospective Cohort Study.

    Science.gov (United States)

    Lycett, Kate; Sciberras, Emma; Hiscock, Harriet; Mensah, Fiona K

    2016-06-01

    Sleep problems affect up to 70% of children with attention-deficit/hyperactivity disorder (ADHD) and are associated with poorer child and family well-being in cross-sectional studies. However, whether these associations hold longitudinally is unclear. The authors aimed to examine the longitudinal relationship between sleep problem trajectories and well-being in children with ADHD. Children with ADHD (n = 186), aged 5 to 13 years, were recruited from 21 pediatric practices across the state of Victoria, Australia. Sleep problem severity data were collected at 3 time points (baseline, 6, and 12 mo) and were used to classify sleep problem trajectories. Child and family well-being (e.g., child emotional and behavioral problems, quality of life [QoL]) were measured at baseline and 12 months by teacher and/or caregiver-report. The well-being of children with "transient" and "persistent" sleep problems was compared with those "never" experiencing sleep problems using a series of hierarchical linear regression models. After accounting for socio-demographic factors, children with transient and persistent sleep trajectories experienced more caregiver-reported behavioral and emotional problems (effect size [ES] both 0.7) and poorer child QoL (ES: -0.7 and -1.2, respectively). These associations remained after also accounting for ADHD medication and symptom severity and comorbidities, but after accounting for baseline measures many associations weakened to the point of nonsignificance. In the fully adjusted model-transient sleep problems were associated with behavioral and emotional problems (ES: 0.2). These associations were not evident by teacher-report. Children with ADHD experiencing transient or persistent sleep problems have poorer caregiver-reported well-being. Managing sleep problems in children with ADHD may improve child well-being.

  9. Trajectories of delinquency and parenting styles

    NARCIS (Netherlands)

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

  10. Trajectories of Delinquency and Parenting Styles

    NARCIS (Netherlands)

    Hoeve, M.; Blokland, A.A.J.; 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

  11. 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.

  12. 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.

  13. Proton transfer to charged platinum electrodes. A molecular dynamics trajectory study.

    Science.gov (United States)

    Wilhelm, Florian; Schmickler, Wolfgang; Spohr, Eckhard

    2010-05-05

    A recently developed empirical valence bond (EVB) model for proton transfer on Pt(111) electrodes (Wilhelm et al 2008 J. Phys. Chem. C 112 10814) has been applied in molecular dynamics (MD) simulations of a water film in contact with a charged Pt surface. A total of seven negative surface charge densities σ between -7.5 and -18.9 µC cm(-2) were investigated. For each value of σ, between 30 and 84 initial conditions of a solvated proton within a water slab were sampled, and the trajectories were integrated until discharge of a proton occurred on the charged surfaces. We have calculated the mean rates for discharge and for adsorption of solvated protons within the adsorbed water layer in contact with the metal electrode as a function of surface charge density. For the less negative values of σ we observe a Tafel-like exponential increase of discharge rate with decreasing σ. At the more negative values this exponential increase levels off and the discharge process is apparently transport limited. Mechanistically, the Tafel regime corresponds to a stepwise proton transfer: first, a proton is transferred from the bulk into the contact water layer, which is followed by transfer of a proton to the charged surface and concomitant discharge. At the more negative surface charge densities the proton transfer into the contact water layer and the transfer of another proton to the surface and its discharge occur almost simultaneously.

  14. Anatomic Assessment of K-Wire Trajectory for Transverse Percutaneous Fixation of Small Finger Metacarpal Fractures: A Cadaveric Study.

    Science.gov (United States)

    Grandizio, Louis C; Speeckaert, Amy; Kozick, Zach; Klena, Joel C

    2018-01-01

    The purpose of this cadaveric study is to evaluate the trajectory of percutaneous transverse Kirschner wire (K-wire) placement for fifth metacarpal fractures relative to the sagittal profile of the fifth metacarpal in order to develop a targeting strategy for the treatment of fifth metacarpal fractures. Using 12 unmatched fresh human upper limbs, we evaluated the trajectory of percutaneous transverse K-wire placement relative to the sagittal profile of the fifth metacarpal in order to develop a targeting strategy for treatment of fifth metacarpal fractures. The midpoint of the small and ring finger metacarpals in the sagittal plane was identified at 3 points. At each point, a K-wire was inserted from the small finger metacarpal into the midpoint of the ring finger metacarpal ("center-center" position). The angle of the transverse K-wire relative to the table needed to achieve a center-center position averaged 20.8°, 18.9°, and 16.7° for the proximal diaphysis, middiaphysis, and the collateral recess, respectively. Approximately 80% of transversely placed K-wires obtained purchase in the long finger metacarpal. These results can serve as a guide to help surgeons in the accurate placement of percutaneous K-wires for small finger metacarpal fractures and may aid in surgeon training.

  15. Identifying developmental trajectories of body mass index in childhood using latent class growth (mixture modelling: associations with dietary, sedentary and physical activity behaviors: a longitudinal study

    Directory of Open Access Journals (Sweden)

    Maaike Koning

    2016-10-01

    Full Text Available Abstract Background To date, many epidemiologic studies examining associations between obesity and dietary and sedentary/physical activity behaviors have focused on assessing Body Mass Index (BMI at one point in time. Recent developments in statistical techniques make it possible to study the potential heterogeneity in the development of BMI during childhood by identifying distinct subpopulations characterized by distinct developmental trajectories. Using Latent Class Growth (Mixture Modelling (LCGMM techniques we aimed to identify BMI trajectories in childhood and to examine associations between these distinct trajectories and dietary, sedentary and physical activity behaviors. Methods This longitudinal study explored BMI standard deviation score (SDS trajectories in a sample of 613 children from 4 to 12 years of age. In 2006, 2009 and 2012 information on children’s health related behaviors was obtained by parental questionnaires, and children’s height and weight were measured. Associations with behaviors were investigated with logistic regression models. Results We identified two BMI SDS trajectories; a decreasing BMI SDS trajectory (n = 416; 68 % and an increasing BMI SDS trajectory (n = 197; 32 %. The increasing BMI SDS trajectory consisted of more participants of lower socio-economic status (SES and of non-western ethnicity. Maternal overweight status was associated with being in the increasing BMI SDS trajectory at both baseline and follow-up six years later (2006: Odds Ratio (OR, 2.9; 95 % confidence interval (CI 1.9 to 4.3; 2012 OR, 1.8; 95 % CI 1.2 to 2.6. The increasing BMI SDS trajectory was associated with the following behaviors; drinking sugared drinks > 3 glasses per day, participation in organized sports  2 h per day, though participation in organized sports at follow-up was the only significant result. Conclusions Our results indicate the importance of healthy lifestyle behaviors at a young age, and

  16. Towards Efficient Search for Activity Trajectories

    DEFF Research Database (Denmark)

    Zheng, Kai; Shang, Shuo; Yuan, Jing

    2013-01-01

    , recent proliferation in location-based web applications (e.g., Foursquare, Facebook) has given rise to large amounts of trajectories associated with activity information, called activity trajectory. In this paper, we study the problem of efficient similarity search on activity trajectory database. Given...

  17. Methods for control over learning individual trajectory

    Science.gov (United States)

    Mitsel, A. A.; Cherniaeva, N. V.

    2015-09-01

    The article discusses models, methods and algorithms of determining student's optimal individual educational trajectory. A new method of controlling the learning trajectory has been developed as a dynamic model of learning trajectory control, which uses score assessment to construct a sequence of studied subjects.

  18. Classical descriptions of the electron trajectories in the He atom

    International Nuclear Information System (INIS)

    Miko, A.; Toekesi, K.

    2006-01-01

    Complete text of publication follows. The classical-trajectory Monte Carlo method (CTMC) treats the atomic systems as small solar-systems, where the electrons are moving around the nucleus in properly chosen Kepler-orbits. It is also well known that the multi-electron classical atomic systems are instable due to the autoionization through electron-electron interactions. Therefore most of the classical descriptions use the so called independent particle approach, i.e. they neclect the electron-electron interactions. In the quasiclassical trajectory Monte Carlo method (QCTMC) appears a qualitative improvement of the classical description of the multi-electron atoms namely the electron-electron interaction is entirely taken into account by the help of the extra potentials providing the validations of the Pauli exclusion principle and the Heisenberg uncertainty principle. The extra potentials ensure that the multi electron atoms are stable even if all electron-electron interactions are taken into account. The extra potentials - representing the constrains - can be written in the following form [1] V τ -2 f(τp; ξ); where f is the monotonic decreasing function of the relative distance τ and momentum p and ξ is the constant characterized the given atomic state. Figure 1. shows the typical electron trajectories in the helium atom. The calculations were carried out using CTMC model when the electron-electron interaction is neglected (Fig. 1a). In this case the He atom is stable and the electron orbits are closed. However, when the electron-electron interaction is taken into account in the CTMC model the electron trajectories in the He atom show chaotic behavior and after a few cycles autoionization occurs (Fig. 1b). In the QCTMC model the electron trajectories are also closed and stable (Fig. 1c). (author)

  19. Experimental Observation of Anisotropic Adler-Bell-Jackiw Anomaly in Type-II Weyl Semimetal WTe1.98 Crystals at the Quasiclassical Regime

    Science.gov (United States)

    Lv, Yang-Yang; Li, Xiao; Zhang, Bin-Bin; Deng, W. Y.; Yao, Shu-Hua; Chen, Y. B.; Zhou, Jian; Zhang, Shan-Tao; Lu, Ming-Hui; Zhang, Lei; Tian, Mingliang; Sheng, L.; Chen, Yan-Feng

    2017-03-01

    The asymmetric electron dispersion in type-II Weyl semimetal theoretically hosts anisotropic transport properties. Here, we observe the significant anisotropic Adler-Bell-Jackiw (ABJ) anomaly in the Fermi-level delicately adjusted WTe1.98 crystals. Quantitatively, CW , a coefficient representing the intensity of the ABJ anomaly along the a and b axis of WTe1.98 are 0.030 and 0.051 T-2 at 2 K, respectively. We found that the temperature-sensitive ABJ anomaly is attributed to a topological phase transition from a type-II Weyl semimetal to a trivial semimetal, which is verified by a first-principles calculation using experimentally determined lattice parameters at different temperatures. Theoretical electrical transport study reveals that the observation of an anisotropic ABJ along both the a and b axes in WTe1.98 is attributed to electrical transport in the quasiclassical regime. Our work may suggest that electron-doped WTe2 is an ideal playground to explore the novel properties in type-II Weyl semimetals.

  20. 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.

  1. 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

    International Nuclear Information System (INIS)

    Miller, William H.; Cotton, Stephen J.

    2016-01-01

    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.

  2. 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.

  3. 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

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William H., E-mail: millerwh@berkeley.edu; Cotton, Stephen J., E-mail: StephenJCotton47@gmail.com [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)

    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.

  4. 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.)

  5. Cluster dynamics: A classical trajectory study of A + A/sub n/arrow-right-leftA*/sub n/+1

    International Nuclear Information System (INIS)

    Brady, J.W.; Doll, J.D.; Thompson, D.L.

    1979-01-01

    The dynamics of the collision of an atom A with a small cluster of atoms, A/sub n/, leading to the formation of a quasibound A*/sub n/+1 complex, which subsequently decays, has been studied using classical trajectories. Pairwise Lennard-Jones potentials (with parameters appropriate for argon) were used to describe the identical point masses (Ar). The results illustrate the feasibility of direct calculations of microscopic rates for nucleation processes. The dissociation of collisionally formed A*/sub n/+1 (n=3,4, and 5) occurs by first-order exponential decay. Furthermore the energy dependence of the dissociation rate constants appears to be well described by the RRK functional form

  6. 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

  7. 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

  8. Au pair trajectories

    DEFF Research Database (Denmark)

    Dalgas, Karina Märcher

    2015-01-01

    pair-sending families in the Philippines, this dissertation examines the long-term trajectories of these young Filipinas. It shows how the au pairs’ local and transnational family relations develop over time and greatly influence their life trajectories. A focal point of the study is how au pairs...... that Filipina au pairs see their stay abroad as an avenue of personal development and social recognition, I examine how the au pairs re-position themselves within their families at home through migration, and how they navigate between the often conflicting expectations of participation in the sociality......Since 2000, thousands of young Filipino migrants have come to Denmark as au pairs. Officially, they are there to “broaden their cultural horizons” by living temporarily with a Danish host family, but they also conduct domestic labor in exchange for food and money, which allows them to send...

  9. 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.

  10. 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

    2016-01-01

    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. PMID:20207459

  11. 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…

  12. Trajectory of social isolation following hip fracture: an analysis of the English Longitudinal Study of Ageing (ELSA) cohort.

    Science.gov (United States)

    Smith, Toby O; Dainty, Jack R; MacGregor, Alex

    2018-01-01

    social isolation is defined as a lack of meaningful and sustained communication or interactions with social networks. There is limited understanding on the prevalence of social isolation and loneliness in people following hip fracture and no previous understanding of how this changes over time. to determine the prevalence and trajectory of social isolation and loneliness before a hip fracture, during the recovery phase and a minimum of 2 years post-hip fracture in an English population. data were from the English Longitudinal Study of Ageing (ELSA) cohort (2004/5-2014/15). The sample comprised of 215 participants who had sustained a hip fracture. Measures of social isolation and loneliness were analysed through multilevel modelling to determine their trajectories during three-time intervals (pre-fracture; interval at hip fracture and recovery; minimum 2 years post-fracture). The prevalence of social isolation and loneliness were determined pre- and post-fracture. prevalence of social isolation was 19% post-hip fracture and loneliness 13% post-hip fracture. There was no statistically significant change in social isolation pre-fracture compared to a minimum of 2 years post-fracture (P = 0.78). Similarly, there was no statistically significant change in loneliness pre-fracture compared to a minimum of 2 years post-fracture (P = 0.12). this analysis has determined that whilst social isolation and loneliness do not change over time following hip fracture, these remain a significant problem for this population. Interventions are required to address these physical and psychological health needs. This is important as they may have short and longer term health benefits for people post-hip fracture. © The Author 2017. Published by Oxford University Press on behalf of the British Geriatrics Society.All rights reserved. For permissions, please email: journals.permissions@oup.com

  13. Objectively measured physical activity and 12-month trajectories of neck-shoulder pain in workers: A prospective study in DPHACTO.

    Science.gov (United States)

    Hallman, David M; Birk Jørgensen, Marie; Holtermann, Andreas

    2017-05-01

    This study aimed to investigate the association between objectively measured physical activity at work and leisure and the intensity (mean level and time course) of neck-shoulder pain (NSP) over 12 months among male and female blue collar workers. Data were obtained from 625 blue collar workers from the Danish cohort DPHACTO. Physical activity was measured objectively at baseline using accelerometers. The percentage of time spent in physical activity (walking, climbing stairs, running and cycling) was calculated for both work and leisure time. Longitudinal data on the intensity of NSP (numerical rating scale 0-10) were collected using text messages every fourth week over 12 months. Linear mixed models were used to investigate the associations between occupational physical activity (OPA) and leisure time physical activity (LTPA) and the trajectories of the intensity of NSP, adjusted for individual, biomechanical and psychosocial factors, and baseline pain. OPA was not associated with the mean intensity of NSP over 12 months. LTPA was negatively associated with the mean intensity of NSP both among men ( B=-0.71, 95% CI -1.31 to -0.11) and women ( B=-0.85, 95% CI -1.57 to -0.13). Sex interactions on the 12-month trajectories of NSP showed that higher physical activity was associated with a slower reduction in NSP among men for OPA only ( B=0.03, 95% CI 0.01-0.05) and women for LTPA only ( B=0.05, 95% CI 0.00-0.09). We found that more time in LTPA was associated with a lower overall intensity of NSP over 12 months among blue collar workers. However, depending on sex and domain, high physical activity had an unfavourable effect on the course of NSP over 12 months.

  14. Developmental Trajectories of Youth Character: A Five-Wave Longitudinal Study of Cub Scouts and Non-Scout Boys.

    Science.gov (United States)

    Wang, Jun; Ferris, Kaitlyn A; Hershberg, Rachel M; Lerner, Richard M

    2015-12-01

    Youth development programs, such as the Boy Scouts of America, aim to develop positive attributes in youth (e.g., character virtues, prosocial behaviors, and positive civic actions), which are necessary for individuals and societies to flourish. However, few developmental studies have focused on how specific positive attributes develop through participation in programs such as the Boy Scouts of America. As part of the Character and Merit Project, this article examined the developmental trajectories of character and other positive attributes, which are of focal concern of the Boy Scouts of America and the developmental literature. Data were collected from 1398 Scouts (M = 8.59 years, SD = 1.29 years, Range 6.17-11.92 years) and 325 non-Scout boys (M = 9.06 years, SD = 1.43 years, Range 6.20-11.81 years) over five waves of testing across a two-and-half-year period. Latent growth-curve analyses of self-report survey data examined the developmental trajectories of the attributes. Older youth rated themselves lower than younger participants on helpfulness, reverence, thriftiness, and school performance. However, all youth had moderately high self-ratings on all the attributes. Across waves, Scouts' self-ratings increased significantly for cheerfulness, helpfulness, kindness, obedience, trustworthiness, and hopeful future expectations. Non-Scout boys' self-ratings showed no significant change for any attributes except for a significant decrease in religious reverence among non-Scout boys from religious institutions. We discuss implications for positive youth development and for the role of the Boy Scouts of America programming in character development.

  15. The trajectory of experience of critical care nurses in providing end-of-life care: A qualitative descriptive study.

    Science.gov (United States)

    Ong, Keh Kiong; Ting, Kit Cheng; Chow, Yeow Leng

    2018-01-01

    To understand the perceptions of critical care nurses towards providing end-of-life care. There has been an increasing interest in end-of-life care in the critical care setting. In Singapore, approximately half of deaths in the hospital occur during critical care. While nurses are well positioned to provide end-of-life care to patients and their family members, they faced barriers to providing end-of-life care. Also, providing end-of-life care has profound positive and negative psychological effects on nurses, with the latter being more prominent. Qualitative descriptive design. Data collection was performed in a medical intensive care unit of a public tertiary hospital in Singapore. Ten registered nurses were purposively sampled and interviewed individually using a semi-structured interview guide. A codebook was developed to guide coding, and data were thematically analysed. Rigour was maintained. Nurses went through a trajectory of experience. They experienced the culture of care and developed dissatisfaction with it. The tension shaped their perception and meaning of life and death, and they developed mechanisms to reach resolution. This study provides insight on nurses' perception as a trajectory of experience and raised several implications on clinical practice, policy and research. There is a need to alleviate the tension nurses face and to facilitate coming to terms with the tension by improving the culture of care and supporting nurses. Nurses could be involved more in decision-making and empowered to start end-of-life care conversations within the team and with family members. Communication with family members and between nurses and doctors could be improved. Support for nurses providing end-of-life care could be enhanced through promoting social networks, education and bereavement support. Further research is needed to explore ways to support and empower nurses to provide end-of-life care in critical care. © 2017 John Wiley & Sons Ltd.

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

    International Nuclear Information System (INIS)

    Mastromatteo, Michael; Jackson, Bret

    2013-01-01

    Electronic structure methods based on density functional theory are used to construct a reaction path Hamiltonian for CH 4 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

  17. A Winding Road--Professional Trajectories from Higher Education to Working Life: A Case Study of Political Science and Psychology Graduates

    Science.gov (United States)

    Nystrom, Sofia; Dahlgren, Madeleine Abrandt; Dahlgren, Lars Owe

    2008-01-01

    This qualitative and longitudinal study focuses on graduate employment and the development of graduate employment paths. The aim of this article is to explore the present professional trajectory from higher education to working life, with particular reference to graduates from two different study programmes at Linkoping University in Sweden:…

  18. Single-collision studies of hot atom energy transfer and chemical reaction

    International Nuclear Information System (INIS)

    Valentini, J.J.

    1991-01-01

    This report discusses research in the collision dynamics of translationally hot atoms, with funding with DOE for the project ''Single-Collision Studies of Hot Atom Energy Transfer and Chemical Reaction,'' Grant Number DE-FG03-85ER13453. The work reported here was done during the period September 9, 1988 through October 31, 1991. During this period this DOE-funded work has been focused on several different efforts: (1) experimental studies of the state-to-state dynamics of the H + RH → H 2 R reactions where RH is CH 4 , C 2 H 6 , or C 3 H 8 , (2) theoretical (quasiclassical trajectory) studies of hot hydrogen atom collision dynamics, (3) the development of photochemical sources of translationally hot molecular free radicals and characterization of the high resolution CARS spectroscopy of molecular free radicals, (4) the implementation of stimulated Raman excitation (SRE) techniques for the preparation of vibrationally state-selected molecular reactants

  19. Childhood predictors of lung function trajectories and future COPD risk: a prospective cohort study from the first to the sixth decade of life.

    Science.gov (United States)

    Bui, Dinh S; Lodge, Caroline J; Burgess, John A; Lowe, Adrian J; Perret, Jennifer; Bui, Minh Q; Bowatte, Gayan; Gurrin, Lyle; Johns, David P; Thompson, Bruce R; Hamilton, Garun S; Frith, Peter A; James, Alan L; Thomas, Paul S; Jarvis, Deborah; Svanes, Cecilie; Russell, Melissa; Morrison, Stephen C; Feather, Iain; Allen, Katrina J; Wood-Baker, Richard; Hopper, John; Giles, Graham G; Abramson, Michael J; Walters, Eugene H; Matheson, Melanie C; Dharmage, Shyamali C

    2018-04-05

    Lifetime lung function is related to quality of life and longevity. Over the lifespan, individuals follow different lung function trajectories. Identification of these trajectories, their determinants, and outcomes is important, but no study has done this beyond the fourth decade. We used six waves of the Tasmanian Longitudinal Health Study (TAHS) to model lung function trajectories measured at 7, 13, 18, 45, 50, and 53 years. We analysed pre-bronchodilator FEV 1 z-scores at the six timepoints using group-based trajectory modelling to identify distinct subgroups of individuals whose measurements followed a similar pattern over time. We related the trajectories identified to childhood factors and risk of chronic obstructive pulmonary disease (COPD) using logistic regression, and estimated population-attributable fractions of COPD. Of the 8583 participants in the original cohort, 2438 had at least two waves of lung function data at age 7 years and 53 years and comprised the study population. We identified six trajectories: early below average, accelerated decline (97 [4%] participants); persistently low (136 [6%] participants); early low, accelerated growth, normal decline (196 [8%] participants); persistently high (293 [12%] participants); below average (772 [32%] participants); and average (944 [39%] participants). The three trajectories early below average, accelerated decline; persistently low; and below average had increased risk of COPD at age 53 years compared with the average group (early below average, accelerated decline: odds ratio 35·0, 95% CI 19·5-64·0; persistently low: 9·5, 4·5-20·6; and below average: 3·7, 1·9-6·9). Early-life predictors of the three trajectories included childhood asthma, bronchitis, pneumonia, allergic rhinitis, eczema, parental asthma, and maternal smoking. Personal smoking and active adult asthma increased the impact of maternal smoking and childhood asthma, respectively, on the early below average, accelerated decline

  20. 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

  1. 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

  2. Adaptive Trajectory Design

    Data.gov (United States)

    National Aeronautics and Space Administration — Adaptive Trajectory Design (ATD) is an original concept for quick and efficient end-to-end trajectory designs using proven piece-wise dynamical methods. With ongoing...

  3. Do body mass index trajectories affect the risk of type 2 diabetes? A case-control study.

    Science.gov (United States)

    Mano, Yoshihiko; Yokomichi, Hiroshi; Suzuki, Kohta; Takahashi, Atsunori; Yoda, Yoshioki; Tsuji, Masahiro; Sato, Miri; Shinohara, Ryoji; Mizorogi, Sonoko; Mochizuki, Mie; Yamagata, Zentaro

    2015-07-28

    Although obesity is a well-studied risk factor for diabetes, there remains an interest in whether "increasing body mass index (BMI)," "high BMI per se," or both are the actual risk factors for diabetes. The present study aimed to retrospectively compare BMI trajectories of individuals with and without diabetes in a case-control design and to assess whether increasing BMI alone would be a risk factor. Using comprehensive health check-up data measured over ten years, we conducted a case-control study and graphically drew the trajectories of BMIs among diabetic patients and healthy subjects, based on coefficients in fitted linear mixed-effects models. Patient group was matched with healthy control group at the onset of diabetes with an optimal matching method in a 1:10 ratio. Simple fixed-effects models assessed the differences in increasing BMIs over 10 years between patient and control groups. At the time of matching, the mean ages in male patients and controls were 59.3 years [standard deviation (SD) = 9.2] and 57.7 years (SD = 11.2), whereas the mean BMIs were 25.0 kg/m(2) (SD = 3.1) and 25.2 kg/m(2) (SD = 2.9), respectively. In female patients and controls, the mean ages were 61.4 years (SD = 7.9) and 60.1 years (SD = 9.6), whereas the mean BMIs were 24.8 kg/m(2) (SD = 3.5) and 24.9 kg/m(2) (SD = 3.4), respectively. The simple fixed-effects models detected no statistical significance for the differences of increasing BMIs between patient and control groups in males (P = 0.19) and females (P = 0.67). Sudden increases in BMI were observed in both male and female patients when compared with BMIs 1 year prior to diabetes onset. The present study suggested that the pace of increasing BMIs is similar between Japanese diabetic patients and healthy individuals. The increasing BMI was not detected to independently affect the onset of type 2 diabetes.

  4. The Effects of the Green House Nursing Home Model on ADL Function Trajectory: A Retrospective Longitudinal Study

    Science.gov (United States)

    YOON, Ju Young; BROWN, Roger L.; BOWERS, Barbara J.; SHARKEY, Siobhan S.; HORN, Susan D.

    2015-01-01

    Background Growing attention in the past few decades has focused on improving care quality and quality of life for nursing home residents. Many traditional nursing homes have attempted to transform themselves to become more homelike emphasizing individualized care. This trend is referred to as nursing home culture change in the U.S. A promising culture change nursing home model, the Green House (GH) nursing home model, has shown positive psychological outcomes. However, little is known about whether the GH nursing home model has positive effects on physical function compared to traditional nursing homes. Objectives To examine the longitudinal effects of the GH nursing home model by comparing change patterns of ADL function over time between GH home residents and traditional nursing home residents. Design A retrospective longitudinal study. Settings Four GH organizations (nine GH units and four traditional units). Participants A total of 242 residents (93 GH residents and 149 traditional home residents) who had stayed in the nursing home at least six months from admission. Methods The outcome was ADL function, and the main independent variable was the facility type in which the resident stayed: a GH or traditional unit. Age, gender, comorbidity score, cognitive function, and depressive symptoms at baseline were controlled. All of these measures were from a minimum dataset. Growth curve modeling and growth mixture modeling were employed in this study for longitudinal analyses. Results The mean ADL function showed deterioration over time, and the rates of deterioration between GH and traditional home residents were not different over time. Four different ADL function trajectories were identified for 18 months, but there was no statistical difference in the likelihood of being in one of the four trajectory classes between the two groups. Conclusions Although GH nursing homes are considered to represent an innovative model changing the nursing home environment into more

  5. The effects of the Green House nursing home model on ADL function trajectory: A retrospective longitudinal study.

    Science.gov (United States)

    Yoon, Ju Young; Brown, Roger L; Bowers, Barbara J; Sharkey, Siobhan S; Horn, Susan D

    2016-01-01

    Growing attention in the past few decades has focused on improving care quality and quality of life for nursing home residents. Many traditional nursing homes have attempted to transform themselves to become more homelike emphasizing individualized care. This trend is referred to as nursing home culture change in the U.S. A promising culture change nursing home model, the Green House nursing home model, has shown positive psychological outcomes. However, little is known about whether the Green House nursing home model has positive effects on physical function compared to traditional nursing homes. To examine the longitudinal effects of the Green House nursing home model by comparing change patterns of activities of daily living function over time between Green House home residents and traditional nursing home residents. A retrospective longitudinal study. Four Green House organizations (nine Green House units and four traditional units). A total of 242 residents (93 Green House residents and 149 traditional home residents) who had stayed in the nursing home at least 6 months from admission. The outcome was activities of daily living function, and the main independent variable was the facility type in which the resident stayed: a Green House or traditional unit. Age, gender, comorbidity score, cognitive function, and depressive symptoms at baseline were controlled. All of these measures were from a minimum dataset. Growth curve modeling and growth mixture modeling were employed in this study for longitudinal analyses. The mean activities of daily living function showed deterioration over time, and the rates of deterioration between Green House and traditional home residents were not different over time. Four different activities of daily living function trajectories were identified for 18 months, but there was no statistical difference in the likelihood of being in one of the four trajectory classes between the two groups. Although Green House nursing homes are

  6. Trajectories of CKD-MBD biochemical parameters over a 2-year period following diagnosis of secondary hyperparathyroidism: a pharmacoepidemiological study.

    Science.gov (United States)

    Filipozzi, Pierre; Ayav, Carole; Ngueyon Sime, Willy; Laurain, Emmanuelle; Kessler, Michèle; Brunaud, Laurent; Frimat, Luc

    2017-03-27

    To define groups of patients according to the changes of biochemical parameters, that is, serum calcium, phosphate and parathyroid hormone (PTH), over a 2-year follow-up period using group-based multi-trajectory modeling (GBMM) among a cohort of dialysis patients with newly diagnosed secondary hyperparathyroidism (SHPT) (ie, PTH≥500 ng/L for the first time) and to compare their patient characteristics and treatments. Pharmacoepidemiological study. In the 12 dialysis units located in the French region of Lorraine. A total of 269 dialysis patients with newly diagnosed SHPT were prospectively included from December 2009 to May 2012 and followed-up for 2 years. We identified four distinct trajectory groups: 'rapid PTH drop' experiencing a rapid and sharp decrease (over weeks) in PTH level associated with decreasing phosphate level within normal range (n=34; 12.7%), 'gradual PTH decrease' experiencing a gradual and continuous decrease (over months) in PTH level and maintaining phosphate at a middle level throughout the study (n=98; 36.4%), 'slow PTH decrease with high phosphate' experiencing a slow decrease in PTH level associated with a relatively high phosphate level (n=105; 39.0%) and 'uncontrolled SHPT' with high levels of PTH and phosphate throughout the study (n=32; 11.9%). Patients in the 'uncontrolled SHPT' group were significantly (p<0.00001) younger than patients in other groups. Kidney Disease Improving Global Outcomes (KDIGO) targets for PTH, phosphate and calcium were reached simultaneously for 14.9% of patients at baseline and 16.7% at the end of the study. Patients were given cinacalcet more frequently at months 3 and 6 in the 'rapid PTH drop' and at month 24 in the 'uncontrolled SHPT' groups. Over 2 years following a new SHPT diagnosis, a younger age and a higher rate of alkaline phosphatase were associated to a continuous uncontrolled SHPT. Patients with the lowest PTH at the end of the follow-up tended to receive more often cinacalcet. Clinical

  7. Trajectory and Relative Dispersion Case Studies and Statistics from the Green River Mesoscale Deformation, Dispersion, and Dissipation Program

    Science.gov (United States)

    Niemann, Brand Lee

    A major field program to study beta-mesoscale transport and dispersion over complex mountainous terrain was conducted during 1969 with the cooperation of three government agencies at the White Sands Missile Range in central Utah. The purpose of the program was to measure simultaneously on a large number of days the synoptic and mesoscale wind fields, the relative dispersion between pairs of particle trajectories and the rate of small scale turbulence dissipation. The field program included measurements during more than 60 days in the months of March, June, and November. The large quantity of data generated from this program has been processed and analyzed to provide case studies and statistics to evaluate and refine Lagrangian variable trajectory models. The case studies selected to illustrate the complexities of mesoscale transport and dispersion over complex terrain include those with terrain blocking, lee waves, and stagnation, as well as those with large vertical wind shears and horizontal wind field deformation. The statistics of relative particle dispersion were computed and compared to the classical theories of Richardson and Batchelor and the more recent theories of Lin and Kao among others. The relative particle dispersion was generally found to increase with travel time in the alongwind and crosswind directions, but in a more oscillatory than sustained or even accelerated manner as predicted by most theories, unless substantial wind shears or finite vertical separations between particles were present. The relative particle dispersion in the vertical was generally found to be small and bounded even when substantial vertical motions due to lee waves were present because of the limiting effect of stable temperature stratification. The data show that velocity shears have a more significant effect than turbulence on relative particle dispersion and that sufficient turbulence may not always be present above the planetary boundary layer for "wind direction shear

  8. 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

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

    OpenAIRE

    Dean Kaptsis; Daniel L. King; Paul H. Delfabbro; Michael Gradisar

    2016-01-01

    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 ...

  10. Adverse trajectories of mental health problems predict subsequent burnout and work-family conflict: A longitudinal study of employed women with children followed over 18 years

    NARCIS (Netherlands)

    Nilsen, W.; Skipstein, A.; Demerouti, E.

    2016-01-01

    Background The long-term consequence of experiencing mental health problems may lead to several adverse outcomes. The current study aims to validate previous identified trajectories of mental health problems from 1993 to 2006 in women by examining their implications on subsequent work and

  11. Pre-event trajectories of mental health and health-related disabilities, and post-event traumatic stress symptoms and health : A 7-wave population-based study

    NARCIS (Netherlands)

    van der Velden, Peter; Bosmans, Mark; van der Meulen, Erik; Vermunt, J.K.

    2016-01-01

    It is unknown to what extent classes of trajectories of pre-event mental health problems (MHP) and health-related disabilities (HRD), predict post-event traumatic stress symptoms (PTSS), MHP and HRD. Aim of the present 7-wave study was to assess the predictive values using a representative sample of

  12. Socioeconomic differences in children’s television viewing trajectory: A population-based prospective cohort study

    NARCIS (Netherlands)

    Yang-Huang, J. (Junwen); A. van Grieken (Amy); H.A. Moll (Henriëtte); V.W.V. Jaddoe (Vincent); A.I. Wijtzes (Anne); H. Raat (Hein)

    2017-01-01

    textabstractWe aimed to evaluate the association between family socioeconomic status and repeatedly measured child television viewing time from early childhood to the school period. We analyzed data on 3,561 Dutch children from the Generation R Study, a population-based study in the Netherlands.

  13. Trajectories of Alcohol Use Disorders and Their Differential Impact: A Population-Based Cohort Study in Goa, India.

    Science.gov (United States)

    Nadkarni, Abhijit; Weiss, Helen A; Bhat, Bhargav; Patel, Vikram

    2017-09-01

    The aim of this study was to examine trajectories of Alcohol Use Disorders (AUD) over a 6 year period and compare the bio-psycho-social correlates between these trajectories. Community-based cohort of 1899 adult men were interviewed in 2006-2008 and 2012-2014. AUD were assessed using the Alcohol Use Disorder Identification Test, and potential correlates including psycho-social problems, morbidity and physiological parameters were measured at follow-up. Logistic regression was conducted to estimate odds ratios (ORs) for the association of persistent and incident AUD, respectively, with the potential correlates. Analyses were weighted to account for sampling design, number of adults aged 18-49 years in the household and non-response. Compared with men who had recovered from AUD, there was strong evidence (P < 0.001) that men with persistent AUD were more likely to have marital problems, tobacco use, and raised Gamma Glutamyl Transferase (GGT) and strong evidence (0.001 < P < 0.01) that they were more likely to have workplace problems, social problems, increased healthcare contact and raised Mean Corpuscular Volume (MCV). Compared with men who did not have AUD at baseline and follow-up, there was strong evidence (P < 0.001) that men with incident AUD were more likely to have workplace problems, social problems, marital problems, tobacco use, and raised GGT and strong evidence (0.001 < P < 0.01) that they were more likely to have hypertension, accident and injuries and Common Mental Disorders (CMD). This community-based longitudinal study of AUD, the first from a low and middle income country, clearly demonstrates significant health and social consequences of AUD in men and highlights the need for interventions for their treatment and prevention. Compared to persistent AUD, recovery from AUD has several benefits in health and social domains. Compared to developing new AUD, not having AUD has several benefits in health and social domains. Sustaining the state of not

  14. Hopefulness predicts resilience after hereditary colorectal cancer genetic testing: a prospective outcome trajectories study

    OpenAIRE

    Chu Annie TW; Bonanno George A; Ho Judy WC; Ho Samuel MY; Chan Emily MS

    2010-01-01

    Abstract Background - Genetic testing for hereditary colorectal cancer (HCRC) had significant psychological consequences for test recipients. This prospective longitudinal study investigated the factors that predict psychological resilience in adults undergoing genetic testing for HCRC. Methods - A longitudinal study was carried out from April 2003 to August 2006 on Hong Kong Chinese HCRC family members who were recruited and offered genetic testing by the Hereditary Gastrointestinal Cancer R...

  15. A longitudinal study of the educational and career trajectories of female participants of an urban informal science education program

    Science.gov (United States)

    Fadigan, Kathleen A.; Hammrich, Penny L.

    2004-10-01

    The purpose of this longitudinal case study is to describe the educational trajectories of a sample of 152 young women from urban, low-income, single-parent families who participated in the Women in Natural Sciences (WINS) program during high school. Utilizing data drawn from program records, surveys, and interviews, this study also attempts to determine how the program affected the participants' educational and career choices to provide insight into the role informal science education programs play in increasing the participation of women and minorities in science, math, engineering, and technology (SMET)-related fields. Findings revealed 109 participants (93.16%) enrolled in a college program following high school completion. Careers in medical or health-related fields followed by careers in SMET emerged as the highest ranking career paths with 24 students (23.76%) and 21 students (20.79%), respectively, employed in or pursuing careers in these areas. The majority of participants perceived having staff to talk to, the job skills learned, and having the museum as a safe place to go as having influenced their educational and career decisions. These findings reflect the need for continued support of informal science education programs for urban girls and at-risk youth.

  16. Adverse trajectories of mental health problems predict subsequent burnout and work-family conflict - a longitudinal study of employed women with children followed over 18 years.

    Science.gov (United States)

    Nilsen, Wendy; Skipstein, Anni; Demerouti, Evangelia

    2016-11-08

    The long-term consequence of experiencing mental health problems may lead to several adverse outcomes. The current study aims to validate previous identified trajectories of mental health problems from 1993 to 2006 in women by examining their implications on subsequent work and family-related outcomes in 2011. Employed women (n = 439) with children were drawn from the Tracking Opportunities and Problems-Study (TOPP), a community-based longitudinal study following Norwegian families across 18 years. Previous identified latent profiles of mental health trajectories (i.e., High; Moderate; Low-rising and Low levels of mental health problems over time) measured at six time points between 1993 and 2006 were examined as predictors of burnout (e.g., exhaustion and disengagement from work) and work-family conflict in 2011 in univariate and multivariate analyses of variance adjusted for potential confounders (age, job demands, and negative emotionality). We found that having consistently High and Moderate symptoms as well as Low-Rising symptoms from 1993 to 2006 predicted higher levels of exhaustion, disengagement from work and work-family conflict in 2011. Findings remained unchanged when adjusting for several potential confounders, but when adjusting for current mental health problems only levels of exhaustion were predicted by the mental health trajectories. The study expands upon previous studies on the field by using a longer time span and by focusing on employed women with children who experience different patterns of mental health trajectories. The long-term effect of these trajectories highlight and validate the importance of early identification and prevention in women experiencing adverse patterns of mental health problems with regards to subsequent work and family-related outcomes.

  17. Tracing the Transition from Study to a Contemporary Creative Working Life: The Trajectories of Professional Musicians

    Science.gov (United States)

    Juuti, Sini; Littleton, Karen

    2012-01-01

    The classical music academy is a site dominated by traditional meanings of creative practice and an image of the professional creative career as solo performer that is fully available to only a very few students after graduating. The purpose of the study reported in this paper is to explore career-young professional pianists' talk about the…

  18. 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…

  19. 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.

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

    Science.gov (United States)

    Kaptsis, Dean; King, Daniel L; Delfabbro, Paul H; Gradisar, Michael

    2016-12-01

    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 ( M age  = 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.

  1. Longitudinal Cognitive Trajectories of Women Veterans from the Women’s Health Initiative Memory Study

    Science.gov (United States)

    Padula, Claudia B.; Weitlauf, Julie C.; Rosen, Allyson C.; Reiber, Gayle; Cochrane, Barbara B.; Naughton, Michelle J.; Li, Wenjun; Rissling, Michelle; Yaffe, Kristine; Hunt, Julie R.; Stefanick, Marcia L.; Goldstein, Mary K.; Espeland, Mark A.

    2016-01-01

    Purpose of the Study: A comparison of longitudinal global cognitive functioning in women Veteran and non-Veteran participants in the Women’s Health Initiative (WHI). Design and Methods: We studied 7,330 women aged 65–79 at baseline who participated in the WHI Hormone Therapy Trial and its ancillary Memory Study (WHIMS). Global cognitive functioning (Modified Mini-Mental State Examination [3MSE]) in Veterans (n = 279) and non-Veterans (n = 7,051) was compared at baseline and annually for 8 years using generalized linear modeling methods. Results: Compared with non-Veterans, Veteran women were older, more likely to be Caucasian, unmarried, and had higher rates of educational and occupational attainment. Results of unadjusted baseline analyses suggest 3MSE scores were similar between groups. Longitudinal analyses, adjusted for age, education, ethnicity, and WHI trial assignment revealed differences in the rate of cognitive decline between groups over time, such that scores decreased more in Veterans relative to non-Veterans. This relative difference was more pronounced among Veterans who were older, had higher educational/occupational attainment and greater baseline prevalence of cardiovascular risk factors (e.g., smoking) and cardiovascular disease (e.g., angina, stroke). Implications: Veteran status was associated with higher prevalence of protective factors that may have helped initially preserve cognitive functioning. However, findings ultimately revealed more pronounced cognitive decline among Veteran relative to non-Veteran participants, likely suggesting the presence of risks that may impact neuropathology and the effects of which were initially masked by Veterans’ greater cognitive reserve. PMID:26615021

  2. Trajectories of psychopathology in extremely low birth weight survivors from early adolescence to adulthood: a 20-year longitudinal study.

    Science.gov (United States)

    Van Lieshout, Ryan J; Ferro, Mark A; Schmidt, Louis A; Boyle, Michael H; Saigal, Saroj; Morrison, Katherine M; Mathewson, Karen J

    2018-04-18

    Individuals born extremely preterm are exposed to significant perinatal stresses that are associated with an increased risk of psychopathology. However, a paucity of longitudinal studies has prevented the empirical examination of long-term, dynamic effects of perinatal adversity on mental health. Here, internalizing and externalizing problems from adolescence through adulthood were compared in individuals born at extremely low birth weight (ELBW; 2,500 g). Internalizing and externalizing data were collected over 20 years in three waves, during adolescence, young adulthood, and adulthood. Growth models were used to compare longitudinal trajectories in a geographically based sample of 151 ELBW survivors and 137 NBW control participants born between 1977 and 1982 matched for age, sex, and socioeconomic status at age 8. After adjusting for sex, socioeconomic and immigrant status, and family functioning, ELBW survivors failed to show the normative, age-related decline in internalizing problems over time relative to their NBW peers (β = .21; p Self-esteem (but not physical health, IQ, or maternal mood) partially mediated the association between ELBW status and internalizing problems. Extremely low birth weight survivors experienced a blunting of the expected improvement in depression and anxiety from adolescence to adulthood. These findings suggest that altered physiological regulatory systems supporting emotional and cognitive processing may contribute to the maintenance of internalizing problems in this population. © 2018 Association for Child and Adolescent Mental Health.

  3. Trajectories of premorbid childhood and adolescent functioning in schizophrenia-spectrum psychoses: A first-episode study.

    Science.gov (United States)

    Horton, Leslie E; Tarbox, Sarah I; Olino, Thomas M; Haas, Gretchen L

    2015-06-30

    Evidence of social and behavioral problems preceding the onset of schizophrenia-spectrum psychoses is consistent with a neurodevelopmental model of these disorders. Here we predict that individuals with a first episode of schizophrenia-spectrum psychoses will evidence one of three patterns of premorbid adjustment: an early deficit, a deteriorating pattern, or adequate or good social adjustment. Participants were 164 (38% female; 31% black) individuals ages 15-50 with a first episode of schizophrenia-spectrum psychoses. Premorbid adjustment was assessed using the Cannon-Spoor Premorbid Adjustment Scale. We compared the fit of a series of growth mixture models to examine premorbid adjustment trajectories, and found the following 3-class model provided the best fit with: a "stable-poor" adjustment class (54%), a "stable-good" adjustment class (39%), and a "deteriorating" adjustment class (7%). Relative to the "stable-good" class, the "stable-poor" class experienced worse negative symptoms at 1-year follow-up, particularly in the social amotivation domain. This represents the first known growth mixture modeling study to examine premorbid functioning patterns in first-episode schizophrenia-spectrum psychoses. Given that the stable-poor adjustment pattern was most prevalent, detection of social and academic maladjustment as early as childhood may help identify people at increased risk for schizophrenia-spectrum psychoses, potentially increasing feasibility of early interventions. Published by Elsevier Ireland Ltd.

  4. Integrating ecosystem services in the assessment of urban energy trajectories – A study of the Stockholm Region

    International Nuclear Information System (INIS)

    Mörtberg, Ulla; Goldenberg, Romain; Kalantari, Zahra; Kordas, Olga; Deal, Brian; Balfors, Berit; Cvetkovic, Vladimir

    2017-01-01

    Urban development trajectories are changing towards compact, energy-efficient cities and renewable energy sources, and this will strongly affect ecosystem services (ES) that cities are dependent on but tend to disregard. Such ES can be provisioning, regulating and cultural ES, around which competition over land resources will increase with energy system shifts. Much of this can be foreseen to take place within urbanising regions that are simultaneously the living environment of a major part of the human population today. In order to inform critical urban policy decisions, tools for integrated assessment of urban energy and transport options and ecosystem services need to be developed. For this purpose, a case study of the Stockholm region was conducted, analysing three scenarios for the future urbanisation of the region, integrating a transport energy perspective and an ES perspective. The results showed that a dense but polycentric development pattern gives more opportunities for sustainable urban development, while the dense monocentric scenario has apparent drawbacks from an ES perspective. The methodology is compatible with a model integration platform for urban policy support and will thus enable integrated policy assessment of complex urban systems, with the goal of increasing their sustainability. - Highlights: • A diffuse urban pattern leads to low access to jobs and high energy consumption. • A dense monocentric urban pattern implies high energy efficiency and low access to ES. • A dense polycentric urban pattern allows for a combination of urban functions. • ES needs to be integrated into sustainability assessments of urban policy options.

  5. 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 (ppain relief by session 14 of treatment, and those with high baseline PLP experienced pain relief by session 21 of treatment. Mirror 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.

  6. 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

    2017-12-01

    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 Elsevier Inc. All rights reserved.

  7. 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

  8. Longitudinal Cognitive Trajectories of Women Veterans from the Women's Health Initiative Memory Study.

    Science.gov (United States)

    Padula, Claudia B; Weitlauf, Julie C; Rosen, Allyson C; Reiber, Gayle; Cochrane, Barbara B; Naughton, Michelle J; Li, Wenjun; Rissling, Michelle; Yaffe, Kristine; Hunt, Julie R; Stefanick, Marcia L; Goldstein, Mary K; Espeland, Mark A

    2016-02-01

    A comparison of longitudinal global cognitive functioning in women Veteran and non-Veteran participants in the Women's Health Initiative (WHI). We studied 7,330 women aged 65-79 at baseline who participated in the WHI Hormone Therapy Trial and its ancillary Memory Study (WHIMS). Global cognitive functioning (Modified Mini-Mental State Examination [3MSE]) in Veterans (n = 279) and non-Veterans (n = 7,051) was compared at baseline and annually for 8 years using generalized linear modeling methods. Compared with non-Veterans, Veteran women were older, more likely to be Caucasian, unmarried, and had higher rates of educational and occupational attainment. Results of unadjusted baseline analyses suggest 3MSE scores were similar between groups. Longitudinal analyses, adjusted for age, education, ethnicity, and WHI trial assignment revealed differences in the rate of cognitive decline between groups over time, such that scores decreased more in Veterans relative to non-Veterans. This relative difference was more pronounced among Veterans who were older, had higher educational/occupational attainment and greater baseline prevalence of cardiovascular risk factors (e.g., smoking) and cardiovascular disease (e.g., angina, stroke). Veteran status was associated with higher prevalence of protective factors that may have helped initially preserve cognitive functioning. However, findings ultimately revealed more pronounced cognitive decline among Veteran relative to non-Veteran participants, likely suggesting the presence of risks that may impact neuropathology and the effects of which were initially masked by Veterans' greater cognitive reserve. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. 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

  10. 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

  11. 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.

  12. 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

    2014-10-01

    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. 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. 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. 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.

  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. Smoking Trajectories during the Perinatal Period and Their Risk Factors: The Nationally Representative French ELFE (Etude Longitudinale Française Depuis l'Enfance) Birth Cohort Study.

    Science.gov (United States)

    El-Khoury, Fabienne; Sutter-Dallay, Anne-Laure; Van Der Waerden, Judith; Surkan, Pamela; Martins, Silvia; Keyes, Katherine; de Lauzon-Guillain, Blandine; Charles, Marie-Aline; Melchior, Maria

    2017-01-01

    In France, rates of perinatal smoking are among the highest worldwide; however, perinatal smoking trajectories and associated factors have still not been adequately researched. Among women participating in the French nationally representative etude longitudinale française depuis l'enfance birth cohort (n = 15,540), perinatal smoking trajectories were estimated using group-based modelling. Associated characteristics were studied using multinomial logistic regression. Four trajectories were identified: non-smokers (59%), quitters (20%), persistent moderate (12%) and persistent heavy (9%) smokers. Older age, being native French, low socioeconomic position, persistent psychological difficulties and alcohol use in pregnancy, lack of social support, partner's smoking, mistimed pregnancy, and child formula feeding at birth were associated with persistent heavy smoking. Most of these factors were also associated, but to a lesser extent, with persistent moderate smoking, except for age and migrant status, which had opposite effects. Women who successfully lost weight prior to pregnancy had higher levels of quitting smoking. Women's long-term smoking trajectories vary in terms of initial tobacco consumption level but also in relation to socio-demographic, psychological, behavioral and partner characteristics. Health professionals in contact with pregnant smokers should address perceived risks and benefits of smoking, including partner's smoking and weight-gain concerns. © 2017 S. Karger AG, Basel.

  15. Vitamin D Insufficiency and Cognitive Function Trajectories in Older Adults: The Rancho Bernardo Study.

    Science.gov (United States)

    Laughlin, Gail A; Kritz-Silverstein, Donna; Bergstrom, Jaclyn; Reas, Emilie T; Jassal, Simerjot K; Barrett-Connor, Elizabeth; McEvoy, Linda K

    2017-01-01

    Evidence of a role for vitamin D (VitD) in cognitive aging is mixed and based primarily on extreme VitD deficiency. We evaluated the association of VitD insufficiency with cognitive function in older, community-dwelling adults living in a temperate climate with year-round sunshine. A population-based longitudinal study of 1,058 adults (median age 75; 62% women) who had cognitive function assessed and serum levels of 25-hydroxyvitaminD (25OHD) measured in 1997-99 and were followed for up to three additional cognitive function assessments over a 12-year period. Overall, 14% (n = 145) of participants had VitD insufficiency defined as 25OHD age, sex, education, and season, VitD insufficiency was associated with poorer baseline performance on the Mini-Mental Status Exam (MMSE) (p = 0.013), Trails Making Test B (Trails B) (p = 0.015), Category Fluency (p = 0.006), and Long Term Retrieval (p = 0.019); differences were equivalent to 5 years of age. For those with VitD insufficiency, the odds of mildly impaired performance at baseline were 38% higher for MMSE (p = 0.08), 78% higher for Trails B (p = 0.017), and 2-fold higher for Category Fluency and Long Term Retrieval (both p = 0.001). VitD insufficiency was not related to the rate of cognitive decline on any test or the risk of developing impaired performance during follow-up. In this population with little VitD deficiency, even moderately low VitD was associated with poorer performance on multiple domains of cognitive function. Low VitD did not predict 12-year cognitive decline. Clinical trials are essential to establish a causal link between VitD and cognitive well-being.

  16. Study on Oil Pressure Characteristics and Trajectory Tracking Control in Shift Process of Wet-Clutch for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Junqiu Li

    2016-01-01

    Full Text Available Accurate control of oil pressure of wet-clutch is of great importance for improving shift quality. Based on dynamic models of two-gear planetary transmission and hydraulic control system, a trajectory tracking model of oil pressure was built by sliding mode control method. An experiment was designed to verify the validity of hydraulic control system, through which the relationship between duty cycle of on-off valve and oil pressure of clutch was determined. The tracking effect was analyzed by simulation. Results showed that oil pressure could follow well the optimal trajectory and the shift quality was effectively improved.

  17. 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.

  18. Trajectories of Delinquency and Parenting Styles

    OpenAIRE

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

    2007-01-01

    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 delinquency trajectories differing in both level and change in seriousness over time: a nondelinquent, minor persisting, moderate desisting, serious persist...

  19. The Gavialis-Tomistoma debate: the contribution of skull ontogenetic allometry and growth trajectories to the study of crocodylian relationships.

    Science.gov (United States)

    Piras, Paolo; Colangelo, Paolo; Adams, Dean C; Buscalioni, Angela; Cubo, Jorge; Kotsakis, Tassos; Meloro, Carlo; Raia, Pasquale

    2010-01-01

    The phylogenetic placement of Tomistoma and Gavialis crocodiles depends largely upon whether molecular or morphological data are utilized. Molecular analyses consider them as sister taxa, whereas morphological/paleontological analyses set Gavialis apart from Tomistoma and other crocodylian species. Here skull allometric trajectories of Tomistoma and Gavialis were contrasted with those of two longirostral crocodylian taxa, Crocodylus acutus and Mecistops cataphractus, to examine similarities in growth trajectories in light of this phylogenetic controversy. Entire skull shape and its two main modules, rostrum and postrostrum, were analyzed separately. We tested differences for both multivariate angles between trajectories and for shape differences at early and late stages of development. Based on a multivariate regression of shape data and size, Tomistoma seems to possess a peculiar rate of growth in comparison to the remaining taxa. However, its morphology at both juvenile and adult sizes is always closer to those of Brevirostres crocodylians, for the entire head shape, as well as the shape of the postrostrum and rostrum. By contrast, the allometric trajectory of Gavialis always begins and ends in a unique region of the multidimensional morphospace. These findings concur with a morphological hypothesis that places Gavialis separate from Brevirostres, and Tomistoma closer to other crocodylids, and provides an additional, and independent, data set to inform on this ongoing phylogenetic discussion. © 2010 Wiley Periodicals, Inc.

  20. Evaluating and Improving a Learning Trajectory for Linear Measurement in Elementary Grades 2 and 3: A Longitudinal Study

    Science.gov (United States)

    Barrett, Jeffrey E.; Sarama, Julie; Clements, Douglas H.; Cullen, Craig; McCool, Jenni; Witkowski-Rumsey, Chepina; Klanderman, David

    2012-01-01

    We examined children's development of strategic and conceptual knowledge for linear measurement. We conducted teaching experiments with eight students in grades 2 and 3, based on our hypothetical learning trajectory for length to check its coherence and to strengthen the domain-specific model for learning and teaching. We checked the hierarchical…

  1. The study of the particle trajectories in the magnetic fields of MARUSYA setup using GEANT 3 package

    International Nuclear Information System (INIS)

    Argintaru, Danut; Besliu, Calin; Jipa, Alexandru; Esanu, Tiberiu; Calin, Marius; Argintaru, Cristina

    2005-01-01

    Using the GEANT 3 package we simulate the trajectories of the detected particles in the MARUSYA (JINR Dubna) setup. The dependence between the particle momenta and TOF, dE/dx, velocities and angles are important both for the detectors design and particle identification (PID). (authors)

  2. Trajectories of martian habitability.

    Science.gov (United States)

    Cockell, Charles S

    2014-02-01

    Beginning from two plausible starting points-an uninhabited or inhabited Mars-this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments.

  3. Fluctuation theorems and atypical trajectories

    International Nuclear Information System (INIS)

    Sahoo, M; Lahiri, S; Jayannavar, A M

    2011-01-01

    In this work, we have studied simple models that can be solved analytically to illustrate various fluctuation theorems. These fluctuation theorems provide symmetries individually to the distributions of physical quantities such as the classical work (W c ), thermodynamic work (W), total entropy (Δs tot ) and dissipated heat (Q), when the system is driven arbitrarily out of equilibrium. All these quantities can be defined for individual trajectories. We have studied the number of trajectories which exhibit behaviour unexpected at the macroscopic level. As the time of observation increases, the fraction of such atypical trajectories decreases, as expected at the macroscale. The distributions for the thermodynamic work and entropy production in nonlinear models may exhibit a peak (most probable value) in the atypical regime without violating the expected average behaviour. However, dissipated heat and classical work exhibit a peak in the regime of typical behaviour only.

  4. Repetitive Rockfall Trajectory Testing

    Directory of Open Access Journals (Sweden)

    Axel Volkwein

    2018-03-01

    Full Text Available Numerical simulations of rockfall trajectories are a standard procedure for evaluating rockfall hazards. For these simulations, corresponding software codes must be calibrated and evaluated based on field data. This study addresses methods of repeatable rockfall tests, and investigates whether it is possible to produce traceable and statistically analysable data. A testing series is described extensively covering how to conduct rockfall experiments and how certain elements of rockfall trajectories can be measured. The tests use acceleration and rotation sensors inside test blocks, a system to determine block positions over time, surveying measurements, and video recordings. All systems are evaluated regarding their usability in the field and for analyses. The highly detailed description of testing methods is the basis for sound understanding and reproducibility of the tests. This article serves as a reference for future publications and other rockfall field tests, both as a guide and as a basis for comparisons. First analyses deliver information on runout with a shadow angle ranging between 21 and 45 degrees for a slope consisting of homogeneous soft soil. A digital elevation model of the test site as well as point clouds of the used test blocks are part of this publication.

  5. 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. .

  6. Long-term temporal trajectories to enhance restoration efficiency and sustainability on large rivers: an interdisciplinary study

    Science.gov (United States)

    Eschbach, David; Schmitt, Laurent; Imfeld, Gwenaël; May, Jan-Hendrik; Payraudeau, Sylvain; Preusser, Frank; Trauerstein, Mareike; Skupinski, Grzegorz

    2018-05-01

    While the history of a fluvial hydrosystem can provide essential knowledge on present functioning, historical context remains rarely considered in river restoration. Here we show the relevance of an interdisciplinary study for improving restoration within the framework of a European LIFE+ project on the French side of the Upper Rhine (Rohrschollen Island). Investigating the planimetric evolution combined with historical high-flow data enabled us to reconstruct pre-disturbance hydromorphological functioning and major changes that occurred on the reach. A deposition frequency assessment combining vertical evolution of the Rhine thalweg, chronology of deposits in the floodplain, and a hydrological model revealed that the period of incision in the main channel corresponded to high rates of narrowing and lateral channel filling. Analysis of filling processes using Passega diagrams and IRSL dating highlights that periods of engineering works were closely related to fine sediment deposition, which also presents concomitant heavy metal accumulation. In fact, current fluvial forms, processes and sediment chemistry around Rohrschollen Island directly reflect the disturbances that occurred during past correction works, and up to today. Our results underscore the advantage of combining functional restoration with detailed knowledge of the past trajectory to (i) understand the functioning of the hydrosystem prior to anthropogenic disturbances, (ii) characterize the human-driven morphodynamic adjustments during the last 2 centuries, (iii) characterize physico-chemical sediment properties to trace anthropogenic activities and evaluate the potential impact of the restoration on pollutant remobilization, (iv) deduce the post-restoration evolution tendency and (v) evaluate the efficiency and sustainability of the restoration effects. We anticipate our approach will expand the toolbox of decision-makers and help orientate functional restoration actions in the future.

  7. Early Childhood IQ Trajectories in Individuals Later Developing Schizophrenia and Affective Psychoses in the New England Family Studies.

    Science.gov (United States)

    Agnew-Blais, Jessica C; Buka, Stephen L; Fitzmaurice, Garrett M; Smoller, Jordan W; Goldstein, Jill M; Seidman, Larry J

    2015-07-01

    Individuals who develop schizophrenia in adulthood exhibit, on average, deficits in childhood cognition relative to healthy controls. However, it remains unclear when in childhood such deficits emerge and whether they are stable across childhood or change (increase or decrease) across development. Importantly, whether the trajectory of childhood cognition differs among youth who later develop affective psychoses (AP) vs schizophrenia as adults remains unresolved. Subjects in the Collaborative Perinatal Project were administered the Stanford-Binet IQ test at age 4 and the Wechsler Intelligence Scale for Children at age 7. A total of 9809 (54.7%) participants in the New England Study sites were tested at both ages, including 37 who later developed schizophrenia spectrum psychoses (SSP) and 39 who later developed AP. Logistic regression models examined the association of level of and change in childhood IQ and later SSP or AP. Lower overall childhood IQ was associated with higher risk of SSP. Additionally, there was a small mean increase in IQ in the SSP group relative to a mean decrease in the control group from age 4 to 7 such that positive change in IQ was significantly associated with a higher risk of SSP. Neither overall level nor change in IQ was associated with risk of AP. The results are consistent with neurocognitive impairment throughout early childhood specifically for children who later develop schizophrenia, affirming the theory of atypical neurodevelopment in premorbid schizophrenia. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Long-term temporal trajectories to enhance restoration efficiency and sustainability on large rivers: an interdisciplinary study

    Directory of Open Access Journals (Sweden)

    D. Eschbach

    2018-05-01

    Full Text Available While the history of a fluvial hydrosystem can provide essential knowledge on present functioning, historical context remains rarely considered in river restoration. Here we show the relevance of an interdisciplinary study for improving restoration within the framework of a European LIFE+ project on the French side of the Upper Rhine (Rohrschollen Island. Investigating the planimetric evolution combined with historical high-flow data enabled us to reconstruct pre-disturbance hydromorphological functioning and major changes that occurred on the reach. A deposition frequency assessment combining vertical evolution of the Rhine thalweg, chronology of deposits in the floodplain, and a hydrological model revealed that the period of incision in the main channel corresponded to high rates of narrowing and lateral channel filling. Analysis of filling processes using Passega diagrams and IRSL dating highlights that periods of engineering works were closely related to fine sediment deposition, which also presents concomitant heavy metal accumulation. In fact, current fluvial forms, processes and sediment chemistry around Rohrschollen Island directly reflect the disturbances that occurred during past correction works, and up to today. Our results underscore the advantage of combining functional restoration with detailed knowledge of the past trajectory to (i understand the functioning of the hydrosystem prior to anthropogenic disturbances, (ii characterize the human-driven morphodynamic adjustments during the last 2 centuries, (iii characterize physico-chemical sediment properties to trace anthropogenic activities and evaluate the potential impact of the restoration on pollutant remobilization, (iv deduce the post-restoration evolution tendency and (v evaluate the efficiency and sustainability of the restoration effects. We anticipate our approach will expand the toolbox of decision-makers and help orientate functional restoration actions in the

  9. Trajectory of Material Hardship and Income Poverty in Families of Children Undergoing Chemotherapy: A Prospective Cohort Study.

    Science.gov (United States)

    Bona, Kira; London, Wendy B; Guo, Dongjing; Frank, Deborah A; Wolfe, Joanne

    2016-01-01

    Poverty is correlated with negative health outcomes in pediatric primary care, and is emerging as a negative prognostic indicator in pediatric oncology. However, measures of poverty amenable to targeted intervention, such as household material hardship (HMH)--including food, energy, and housing insecurity--have not been described in pediatric oncology. We describe the trajectory of family reported HMH and income poverty at a pediatric oncology referral center in New England with high psychosocial supports. Single site, prospective cohort study including 99 English-speaking families of children receiving chemotherapy for primary cancer. Families completed face-to-face surveys at two time-points: (1) Within 30 days of child's diagnosis (T1) (N = 99, response rate 88%); (2) 6-months following diagnosis (T2) (N = 93, response rate 94%). HMH was assessed in three domains: food, energy, and housing insecurity. Twenty percent of families reported low-income (≤200% Federal Poverty Level) and at least one HMH prior to their child's diagnosis. At T2, 25% of families lost >40% annual household income secondary to treatment-related work disruptions, and 29% of families reported HMH despite utilization of psychosocial supports. Low-income and HMH are prevalent in a significant proportion of newly diagnosed pediatric oncology families at a large referral center. Despite psychosocial supports, the proportion of families experiencing unmet basic needs increases during chemotherapy to nearly one in three families. HMH provides a quantifiable and remediable measure of poverty in pediatric oncology. Interventions to ameliorate this concrete component of poverty could benefit a significant proportion of pediatric oncology families. © 2015 Wiley Periodicals, Inc.

  10. Labour market trajectories following sickness absence due to self-reported all cause morbidity--a longitudinal study.

    Science.gov (United States)

    Pedersen, Pernille; Lund, Thomas; Lindholdt, Louise; Nohr, Ellen A; Jensen, Chris; Søgaard, Hans Jørgen; Labriola, Merete

    2016-04-16

    To investigate differences in return to work (RTW) and employment trajectories in individuals on sick leave for either mental health reasons or other health related reasons. This study was based on 2036 new sickness absence cases who completed a questionnaire on social characteristics, expectations for RTW and reasons for sickness absence. They were divided into two exposure groups according to their self-reported sickness absence reason: mental health reasons or other health reasons. The outcome was employment status during the following 51 weeks and was measured both as time-to-event analysis and with sequence analysis. Individuals with mental health reasons for sickness absence had a higher risk of not having returned to work (RR 0.87 (0.80;0.93)). Adjusting for gender, age, education and employment did not change the estimate, however, after adding RTW expectations to the model, the excess risk was no longer present (RR 1.01 (0.95;1.08)). In relation to the sequence analysis, individuals with mental health related absence had significantly higher odds of being in the sickness absence cluster and significantly lower odds for being in the fast RTW cluster, but when adjusting for RTW expectations, the odds were somewhat attenuated and no longer significant. Employees on sick leave due to self-reported mental health problems spent more weeks in sickness absence and temporary benefits and had a higher risk of not having returned to work within a year compared to employees on sick leave due to other health reasons. The difference could be explained by their lower RTW expectations at baseline. This emphasises the need to develop suitable and specific interventions to facilitate RTW for this group of sickness absentees.

  11. 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...

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Nina T Rogers

    Full Text Available 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.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.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.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.Healthy non-frail older adults require higher intensities of physical activity for continued improvement in frailty trajectories.

  14. 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.

  15. 3D trajectories re-construction of droplets ejected in controlled tungsten melting studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Yang, Zhongshi; Krieger, K.; Lunt, T.; Brochard, F.; Briancon, J.-L.; Neu, R.; Dux, R.; Janzer, A.; Potzel, S.; Pütterich, T.

    2013-01-01

    Two fast visible range camera systems with vertically and tangentially oriented crossed viewing fields in the divertor region of ASDEX Upgrade were used to observe tungsten (W) droplets ejected from a melting W-pin into the divertor plasma. To obtain the spatial (3D) trajectories of the tungsten droplets, the trajectory of a given droplet in the (2D) camera image coordinate system was derived for each view separately. From these data, the 3D droplet position was derived by computing the shortest line segment connecting crossed viewing chords to a given droplet taking the centre coordinate of the line segment as actual coordinate. The experimental error of the derived position was estimated from the length of the connecting line segment. In the toroidal direction, the computed trajectories can be described by an analytical transport model for the droplets assuming an initial droplet diameter in the range of 60–100 μm. In the vertical direction the vertical distance droplets travelled when reaching the edge of the viewing field also agrees with the model predictions. However, discrepancies are found with respect to the time point whence a droplet reverts its initial downwards motion due to centrifugal forces exceeding gravity and plasma generated force components

  16. Sense of coherence predicts post-myocardial infarction trajectory of leisure time physical activity: a prospective cohort study

    Directory of Open Access Journals (Sweden)

    Gerber Yariv

    2011-09-01

    Full Text Available Abstract Background Physical activity confers a survival advantage after myocardial infarction (MI, yet the majority of post-MI patients are not regularly active. Since sense of coherence (SOC has been associated with health outcomes and some health behaviours, we investigated whether it plays a role in post-MI physical activity. We examined the predictive role of SOC in the long-term trajectory of leisure time physical activity (LTPA after MI using a prospective cohort design. Methods A cohort of 643 patients aged ≤ 65 years admitted to hospital in central Israel with incident MI between February 1992 and February 1993 were followed up for 13 years. Socioeconomic, clinical and psychological factors, including SOC, were assessed at baseline, and LTPA was self-reported on 5 separate occasions during follow-up. The predictive role of SOC in long-term trajectory of LTPA was assessed using generalized estimating equations. Results SOC was consistently associated with engagement in LTPA throughout follow-up. Patients in the lowest SOC tertile had almost twice the odds (odds ratio,1.99; 95% confidence interval,1.52-2.60 of decreasing their engagement in LTPA as those in the highest tertile. A strong association remained after controlling for disease severity, depression, sociodemographic and clinical factors. Conclusion Our evidence suggests that SOC predicts LTPA trajectory post-MI. Assessment of SOC can help identify high-risk MI survivors, who may require additional help in following secondary prevention recommendations which can dramatically improve prognosis.

  17. 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

  18. A classical trajectory study of the photodissociation of T1 acetaldehyde: The transition from impulsive to statistical dynamics

    International Nuclear Information System (INIS)

    Thompson, Keiran C.; Crittenden, Deborah L.; Kable, Scott H.; Jordan, Meredith J.T.

    2006-01-01

    Previous experimental and theoretical studies of the radical dissociation channel of T 1 acetaldehyde show conflicting behavior in the HCO and CH 3 product distributions. To resolve these conflicts, a full-dimensional potential-energy surface for the dissociation of CH 3 CHO into HCO and CH 3 fragments over the barrier on the T 1 surface is developed based on RO-CCSD(T)/cc-pVTZ(DZ) ab initio calculations. 20 000 classical trajectories are calculated on this surface at each of five initial excess energies, spanning the excitation energies used in previous experimental studies, and translational, vibrational, and rotational distributions of the radical products are determined. For excess energies near the dissociation threshold, both the HCO and CH 3 products are vibrationally cold; there is a small amount of HCO rotational excitation and little CH 3 rotational excitation, and the reaction energy is partitioned dominantly (>90% at threshold) into relative translational motion. Close to threshold the HCO and CH 3 rotational distributions are symmetrically shaped, resembling a Gaussian function, in agreement with observed experimental HCO rotational distributions. As the excess energy increases the calculated HCO and CH 3 rotational distributions are observed to change from a Gaussian shape at threshold to one more resembling a Boltzmann distribution, a behavior also seen by various experimental groups. Thus the distribution of energy in these rotational degrees of freedom is observed to change from nonstatistical to apparently statistical, as excess energy increases. As the energy above threshold increases all the internal and external degrees of freedom are observed to gain population at a similar rate, broadly consistent with equipartitioning of the available energy at the transition state. These observations generally support the practice of separating the reaction dynamics into two reservoirs: an impulsive reservoir, fed by the exit channel dynamics, and a

  19. 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.

  20. Quantum dynamical effects as a singular perturbation for observables in open quasi-classical nonlinear mesoscopic systems

    International Nuclear Information System (INIS)

    Berman, G.P.; Borgonovi, F.; Dalvit, D.A.R.

    2009-01-01

    We review our results on a mathematical dynamical theory for observables for open many-body quantum nonlinear bosonic systems for a very general class of Hamiltonians. We show that non-quadratic (nonlinear) terms in a Hamiltonian provide a singular 'quantum' perturbation for observables in some 'mesoscopic' region of parameters. In particular, quantum effects result in secular terms in the dynamical evolution, that grow in time. We argue that even for open quantum nonlinear systems in the deep quasi-classical region, these quantum effects can survive after decoherence and relaxation processes take place. We demonstrate that these quantum effects in open quantum systems can be observed, for example, in the frequency Fourier spectrum of the dynamical observables, or in the corresponding spectral density of noise. Estimates are presented for Bose-Einstein condensates, low temperature mechanical resonators, and nonlinear optical systems prepared in large amplitude coherent states. In particular, we show that for Bose-Einstein condensate systems the characteristic time of deviation of quantum dynamics for observables from the corresponding classical dynamics coincides with the characteristic time-scale of the well-known quantum nonlinear effect of phase diffusion.

  1. Quasiclassical Theory of Spin Imbalance in a Normal Metal-Superconductor Heterostructure with a Spin-Active Interface

    International Nuclear Information System (INIS)

    Shevtsov, O; Löfwander, T

    2014-01-01

    Non-equilibrium phenomena in superconductors have attracted much attention since the first experiments on charge imbalance in the early 1970's. Nowadays a new promising line of research lies at an intersection between superconductivity and spintronics. Here we develop a quasiclassical theory of a single junction between a normal metal and a superconductor with a spin-active interface at finite bias voltages. Due to spin-mixing and spin-filtering effects of the interface a non-equilibrium magnetization (or spin imbalance) is induced at the superconducting side of the junction, which relaxes to zero in the bulk. A peculiar feature of the system is the presence of interface-induced Andreev bound states, which influence the magnitude and the decay length of spin imbalance. Recent experiments on spin and charge density separation in superconducting wires required external magnetic field for observing a spin signal via non-local measurements. Here, we propose an alternative way to observe spin imbalance without applying magnetic field

  2. Heterogeneity in 10-Year Course Trajectories of Moderate to Severe Major Depressive Disorder: A Danish National Register-Based Study.

    Science.gov (United States)

    Musliner, Katherine L; Munk-Olsen, Trine; Laursen, Thomas M; Eaton, William W; Zandi, Peter P; Mortensen, Preben B

    2016-04-01

    Evidence suggests that long-term trajectories of major depressive disorder (MDD) are heterogeneous. The Danish Psychiatric Central Research Register (DPCRR) provides a rare opportunity to examine patterns and correlates of long-term trajectories in a large sample of patients with moderate to severe MDD. To characterize patterns and correlates of 10-year course trajectories of MDD in the DPCRR. A cohort containing 11 640 individuals born in Denmark in 1955 or later with their first recorded MDD diagnosis in the DPCRR between 1995 and 2002 was established. Patients were followed for 10 years from the date of their initial MDD diagnosis. Data were obtained from Danish civil and psychiatric national registers in June 2013 and were analyzed from April 4, 2014, to December 17, 2015. Correlates of trajectory class membership were sex, characteristics of the first recorded MDD episode (ie, age, severity, inpatient treatment, and record of suicide attempt or self-harm), and psychiatric diagnoses in parents (ie, depression, bipolar disorder, schizophrenia-spectrum disorders, substance abuse, and anxiety or somatoform disorders). The outcome variable was past-year contact at a psychiatric hospital with a main diagnosis of MDD during each of the 10 years following the initial MDD diagnosis. Trajectories were modeled using latent class growth analysis. The sample included 11 640 individuals (7493 [64.4%] women) aged 18 to 48 years (mean [SD], 31.4 [7.3]) at their first recorded MDD diagnosis. Four trajectory classes were identified: brief contact (77.0%) (characterized by low probability of contact after 2 years); prolonged initial contact (12.8%) (characterized by high decreasing probability of contact during the first 5 years); later reentry (7.1%) (characterized by moderate probability of contact during the second 5 years); and persistent contact (3.1%) (characterized by high or moderate probability of contact throughout). Female sex (odds ratio [OR] range, 1

  3. Parallel trajectory similarity joins in spatial networks

    KAUST Repository

    Shang, Shuo

    2018-04-04

    The matching of similar pairs of objects, called similarity join, is fundamental functionality in data management. We consider two cases of trajectory similarity joins (TS-Joins), including a threshold-based join (Tb-TS-Join) and a top-k TS-Join (k-TS-Join), where the objects are trajectories of vehicles moving in road networks. Given two sets of trajectories and a threshold θ, the Tb-TS-Join returns all pairs of trajectories from the two sets with similarity above θ. In contrast, the k-TS-Join does not take a threshold as a parameter, and it returns the top-k most similar trajectory pairs from the two sets. The TS-Joins target diverse applications such as trajectory near-duplicate detection, data cleaning, ridesharing recommendation, and traffic congestion prediction. With these applications in mind, we provide purposeful definitions of similarity. To enable efficient processing of the TS-Joins on large sets of trajectories, we develop search space pruning techniques and enable use of the parallel processing capabilities of modern processors. Specifically, we present a two-phase divide-and-conquer search framework that lays the foundation for the algorithms for the Tb-TS-Join and the k-TS-Join that rely on different pruning techniques to achieve efficiency. For each trajectory, the algorithms first find similar trajectories. Then they merge the results to obtain the final result. The algorithms for the two joins exploit different upper and lower bounds on the spatiotemporal trajectory similarity and different heuristic scheduling strategies for search space pruning. Their per-trajectory searches are independent of each other and can be performed in parallel, and the mergings have constant cost. An empirical study with real data offers insight in the performance of the algorithms and demonstrates that they are capable of outperforming well-designed baseline algorithms by an order of magnitude.

  4. Parallel trajectory similarity joins in spatial networks

    KAUST Repository

    Shang, Shuo; Chen, Lisi; Wei, Zhewei; Jensen, Christian S.; Zheng, Kai; Kalnis, Panos

    2018-01-01

    The matching of similar pairs of objects, called similarity join, is fundamental functionality in data management. We consider two cases of trajectory similarity joins (TS-Joins), including a threshold-based join (Tb-TS-Join) and a top-k TS-Join (k-TS-Join), where the objects are trajectories of vehicles moving in road networks. Given two sets of trajectories and a threshold θ, the Tb-TS-Join returns all pairs of trajectories from the two sets with similarity above θ. In contrast, the k-TS-Join does not take a threshold as a parameter, and it returns the top-k most similar trajectory pairs from the two sets. The TS-Joins target diverse applications such as trajectory near-duplicate detection, data cleaning, ridesharing recommendation, and traffic congestion prediction. With these applications in mind, we provide purposeful definitions of similarity. To enable efficient processing of the TS-Joins on large sets of trajectories, we develop search space pruning techniques and enable use of the parallel processing capabilities of modern processors. Specifically, we present a two-phase divide-and-conquer search framework that lays the foundation for the algorithms for the Tb-TS-Join and the k-TS-Join that rely on different pruning techniques to achieve efficiency. For each trajectory, the algorithms first find similar trajectories. Then they merge the results to obtain the final result. The algorithms for the two joins exploit different upper and lower bounds on the spatiotemporal trajectory similarity and different heuristic scheduling strategies for search space pruning. Their per-trajectory searches are independent of each other and can be performed in parallel, and the mergings have constant cost. An empirical study with real data offers insight in the performance of the algorithms and demonstrates that they are capable of outperforming well-designed baseline algorithms by an order of magnitude.

  5. Path-based Queries on Trajectory Data

    DEFF Research Database (Denmark)

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

    2014-01-01

    In traffic research, management, and planning a number of path-based analyses are heavily used, e.g., for computing turn-times, evaluating green waves, or studying traffic flow. These analyses require retrieving the trajectories that follow the full path being analyzed. Existing path queries cannot...... sufficiently support such path-based analyses because they retrieve all trajectories that touch any edge in the path. In this paper, we define and formalize the strict path query. This is a novel query type tailored to support path-based analysis, where trajectories must follow all edges in the path...... 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...

  6. 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.

  7. 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.

    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

  8. 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

  9. 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

  10. 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.

  11. Association of 10-year C-reactive protein trajectories with markers of healthy aging: findings from the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Lassale, Camille; Batty, G David; Steptoe, Andrew; Cadar, Dorina; Akbaraly, Tasnime N; Kivimäki, Mika; Zaninotto, Paola

    2018-02-15

    Elevated systematic inflammation is a hallmark of aging, but the association of long-term inflammation trajectories with subsequent aging phenotypes has been little examined. We assessed inflammatory marker C-reactive protein (CRP) repeatedly over time and examined whether long-term changes predicted aging outcomes. A total of 2,437 men and women aged 47-87 years at baseline (1998-2001) who were participants in the English Longitudinal Study of Ageing had CRP measured on two or three occasions between 1998 and 2009. Inflammation trajectories were computed using latent-class growth mixture modelling and were related to aging outcomes measured in 2012/2013: physical functioning, cardiometabolic, respiratory, mental health, and a composite "healthy aging" outcome. Four CRP trajectories were identified: 'stable-low' (71% of the sample) with baseline mean 1.33mg/L remaining <3mg/L; 'medium-to-high' (14%) with baseline 2.7mg/L rising to 5.3mg/L; 'high-to-medium' (10%) with baseline 6.6mg/L decreasing to 2.4mg/L; 'stable-high' (5%) with levels from 5.7 to 7.5mg/L. Relative to the stable-low trajectory, individuals in the medium-to-high had a higher risk of limitations in basic activities of daily living (ADL, Odds Ratio; 95% Confidence Interval: 2.09; 1.51,2.88), instrumental ADL (1.62; 1.15,2.30), impaired balance (1.59; 1.20,2.11) and walking speed (1.61; 1.15,2.24), arthritis (1.55; 1.16,2.06), hypertension (1.57; 1.21,2.04), obesity (1.95; 1.36,2.80), poor respiratory function (1.84; 1.36,2.50), and depression (1.55; 1.13,2.12). A lower odds of healthy aging was observed in people in the medium-to-high (0.57; 0.40,0.79) and stable-high (0.50; 0.27,0.91) trajectories. Older people who displayed an elevation in CRP levels over a decade experienced an increased risk of adverse aging outcomes.

  12. Picking Robot Arm Trajectory Planning Method

    Directory of Open Access Journals (Sweden)

    Zhang Zhiyong

    2014-01-01

    Full Text Available The picking robot arm is scheduled to complete picking tasks in the working space, to overcome the shaking vibration to improve the picking stability, its movement should follow specific consistence trajectory points. Usually we should give definite multiple feature picking points, map their inverse kinematics to the joint space, establish motion equation for the corresponding point in the joint space, then follow these equations motion for the interpolation on the joint so that we can meet the movement requirements. Trajectory planning is decisive significance for accuracy and stability of controlling robot arm. The key issue that picking arm complete picking task will be come true by trajectory planning, namely, robot arm track the desired trajectory. which based on kinematics and statics picking analysis in a joint space according to the requirements of picking tasks, and obtain the position and orientation for picking robot arm, study and calculate the theory of trajectory parameters timely.

  13. 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

    2008-02-01

    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 delinquency trajectories differing in both level and change in seriousness over time: a nondelinquent, minor persisting, moderate desisting, serious persisting, and serious desisting trajectory. More serious delinquents tended to more frequently engage in delinquency, and to report a higher proportion of theft. Proportionally, serious persistent delinquents were the most violent of all trajectory groups. Using cluster analysis we identified three parenting styles: authoritative, authoritarian (moderately supportive), and neglectful (punishing). Controlling for demographic characteristics and childhood delinquency, neglectful parenting was more frequent in moderate desisters, serious persisters, and serious desisters, suggesting that parenting styles differentiate non- or minor delinquents from more serious delinquents.

  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. 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.

  16. Theory of the paraxial ion trajectory in the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan

    2000-01-01

    This paper presents the analytical and numerical theory of the paraxial ion trajectory through the spiral inflector. Analytical expressions for the equations which describe the paraxial ion trajectory are derived. The analytical derivations of the electric field expansion around the central ion trajectory has also been studied

  17. Pneumatic motor speed control by trajectory tracking fuzzy logic

    Indian Academy of Sciences (India)

    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 ...

  18. 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…

  19. A classical trajectory study of the adatom -surface bond dissociation in the collision reaction between an adsorbed H atom and an N2 molecule

    International Nuclear Information System (INIS)

    Bayhan, U.

    2005-01-01

    The collisionnal dissociation of the Adatom-Surface bond in the diatomic molecule N2(gas)/H(ads) collision taking place on a W(100) bcc-structure surface have been studied by classical trajectory method over the collision energy ranges (0.1-2.0 eV ) and the attractive well depth (0.19-4.0 eV). of the N2 molecule (gas)/H(ads) interactions. When the energy accumulate into the adatom bond, thus leading to a a large dissociation probability

  20. Trajectory Optimization and Conceptual Study of Small Test Vehicles for Hypersonic Engine Using High-Altitude Balloon

    Science.gov (United States)

    Tsuchiya, Takeshi; Takenaka, Youichi; Taguchi, Hideyuki; Sawai, Shujiro

    Japan Aerospace Exploration Agency, JAXA announced a long-term vision recently. In the vision, JAXA aims to develop hypersonic aircrafts. A pre-cooled turbojet engine has great potential as one of newly developed hypersonic air-breathing engines. We also expect the engine to be installed in space transportation vehicles in future. For combustion test in real flight condition of the engines, JAXA has an experimental plan with a small test vehicle falling from a high-altitude balloon. This paper applies numerical analysis and optimization techniques to conceptual designs of the test vehicle in order to obtain the best configuration and trajectory that can achieve the flight test. The results show helpful knowledge when we design prototype vehicles.

  1. Trajectory Optimization and Conceptual Study of Small Test Vehicles for a Hypersonic Engine Using a High-Altitude Balloon

    Science.gov (United States)

    Tsuchiya, Takeshi; Takenaka, Youichi; Taguchi, Hideyuki; Sawai, Shujiro

    The Japan Aerospace Exploration Agency, JAXA, announced a long-term vision recently. In the vision, JAXA aims to develop hypersonic aircrafts. A pre-cooled turbojet engine has great potential as one of newly developed hypersonic airbreathing engines. We also expect the engine to be installed in space transportation vehicles in the future. For combustion test in the real flight conditions of the engines, JAXA has an experimental plan where a small test vehicle is released from a high-altitude balloon. This paper applies numerical analysis and optimization techniques to conceptual designs of the test vehicle in order to obtain the best configuration and trajectory for the flight test. The results show helpful knowledge for designing prototype vehicles.

  2. Delineating the trajectories of social and occupational functioning of young people attending early intervention mental health services in Australia: a longitudinal study.

    Science.gov (United States)

    Iorfino, Frank; Hermens, Daniel F; Cross, Shane Pm; Zmicerevska, Natalia; Nichles, Alissa; Badcock, Caro-Anne; Groot, Josine; Scott, Elizabeth M; Hickie, Ian B

    2018-03-27

    Mental disorders typically emerge during adolescence and young adulthood and put young people at risk for prolonged socioeconomic difficulties. This study describes the longitudinal course of social and occupational functioning of young people attending primary care-based, early intervention services. A longitudinal study of young people receiving mental healthcare. Data were collected between January 2005 and August 2017 from a designated primary care-based mental health service. 554 young people (54% women) aged 12-32 years. A systematic medical file audit collected clinical and functional information at predetermined time intervals (ie, 3 months to 5+ years) using a clinical pro forma. Group-based trajectory modelling (GBTM) was used to identify distinct trajectories of social and occupational functioning over time (median number of observations per person=4; median follow-up time=23 months). Between first clinical contact and time last seen, 15% of young people had reliably deteriorated, 23% improved and 62% did not demonstrate substantive change in function. Of the whole cohort, 69% had functional scores less than 70 at time last seen, indicative of ongoing and substantive impairment. GBTM identified six distinct functional trajectories whereby over 60% had moderate-to-serious functional impairment at entry and remained chronically impaired over time; 7% entered with serious impairment and deteriorated further; a quarter were mildly impaired at entry and functionally recovered and only a small minority (4%) presented with serious impairments and functionally improved over time. Not being in education, employment or training, previous hospitalisation and a younger age at baseline emerged as significant predictors of these functional trajectories. Young people with emerging mental disorders have significant functional impairment at presentation for care, and for the majority, it persists over the course of clinical care. In addition to providing clinical care

  3. An Innovative Context-Based Crystal-Growth Activity Space Method for Environmental Exposure Assessment: A Study Using GIS and GPS Trajectory Data Collected in Chicago.

    Science.gov (United States)

    Wang, Jue; Kwan, Mei-Po; Chai, Yanwei

    2018-04-09

    Scholars in the fields of health geography, urban planning, and transportation studies have long attempted to understand the relationships among human movement, environmental context, and accessibility. One fundamental question for this research area is how to measure individual activity space, which is an indicator of where and how people have contact with their social and physical environments. Conventionally, standard deviational ellipses, road network buffers, minimum convex polygons, and kernel density surfaces have been used to represent people's activity space, but they all have shortcomings. Inconsistent findings of the effects of environmental exposures on health behaviors/outcomes suggest that the reliability of existing studies may be affected by the uncertain geographic context problem (UGCoP). This paper proposes the context-based crystal-growth activity space as an innovative method for generating individual activity space based on both GPS trajectories and the environmental context. This method not only considers people's actual daily activity patterns based on GPS tracks but also takes into account the environmental context which either constrains or encourages people's daily activity. Using GPS trajectory data collected in Chicago, the results indicate that the proposed new method generates more reasonable activity space when compared to other existing methods. This can help mitigate the UGCoP in environmental health studies.

  4. 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....

  5. Developmental Trajectories of Hand Movements in Typical Infants and Those at Risk of Developmental Disorders: An Observational Study of Kinematics during the First Year of Life

    Directory of Open Access Journals (Sweden)

    Lisa Ouss

    2018-02-01

    are significantly associated with age in cohorts of typical and at-risk infantsdiffer significantly at 5–6 months of age, depending on the context: relating either with an object or a person.Environmental and developmental factors shape the developmental trajectories of hand movements in different cohorts: environment for infants with VIMs; stage of development for premature infants and those with West syndrome; and both factors for infants with orality disorders.The curvature of hand movements specifically reflects atypical development in infants with West syndrome when developmental age is considered.We aimed to discriminate between typical and atypical developmental trajectory patterns of at-risk infants in an interactive setting in this observational and longitudinal study, with the assumption that hand movements (HM reflect preverbal communication and its disorders. We examined the developmental trajectories of HM in five cohorts of at-risk infants and one control cohort, followed from ages 2 to 10 months: 25 West syndrome (WS, 13 preterm birth (PB, 16 orality disorder (OD, 14 with visually impaired mothers (VIM, 7 early hospitalization (EH, and 19 typically developing infants (TD. Video-recorded data were collected in three different structured interactive contexts. Descriptors of the hand motion were used to examine the extent to which HM were associated with age and cohort. We obtained four principal results: (i the kinematics of HM (spatial use, curvature, acceleration, and velocity were significantly associated with age in all cohorts; (ii HM significantly differed at 5–6 months of age in TD infants, depending on the context; (iii environmental and developmental factors shaped the developmental trajectories of HM in different cohorts: environment for VIM, development for PB and WS, and both factors for OD and; (iv the curvatures of HM showed atypical development in WS infants when developmental age was considered. These findings support the importance

  6. A prospective study of the impact of child maltreatment and friend support on psychological distress trajectory: From adolescence to emerging adulthood.

    Science.gov (United States)

    Dion, Jacinthe; Matte-Gagné, Célia; Daigneault, Isabelle; Blackburn, Marie-Eve; Hébert, Martine; McDuff, Pierre; Auclair, Julie; Veillette, Suzanne; Perron, Michel

    2016-01-01

    Transition into adulthood is a critical developmental period that may be influenced by adverse life events as well as by protective factors. This study aimed at investigating the effect of different forms of child maltreatment experienced prior to age 14 (i.e., sexual abuse, physical abuse and exposure to intimate partner violence), and of friend support at age 14 on the psychological distress trajectory from age 14 to 24. Participants were 605 adolescents from the general population involved in a 10-year longitudinal study. Psychological distress was evaluated at ages 14, 16, 18 and 24. Child maltreatment prior to 14 years was retrospectively assessed at 14 and 24 years while perception of support from friends was evaluated at age 14. Multilevel growth modeling indicated that psychological distress followed a significant decreasing curvilinear trajectory, with participants reporting fewer distressing psychological symptoms after 18 years. All three forms of child maltreatment, as well as their cumulative effect, predicted more psychological distress over 10 years above and beyond the protective effect of support from friends. Higher support from friends at age 14 was related to lower distress at baseline andover 10 years, beyond the effect of child maltreatment. Self-report nature of all measures, attrition, and measures of child maltreatment forms. Psychological distress decreased during the transition from adolescence to emerging adulthood. Results also revealed the detrimental impact of child maltreatment and the promotive role of friend support, which underscore the importance of early intervention. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Efficient Trajectory Options Allocation for the Collaborative Trajectory Options Program

    Science.gov (United States)

    Rodionova, Olga; Arneson, Heather; Sridhar, Banavar; Evans, Antony

    2017-01-01

    The Collaborative Trajectory Options Program (CTOP) is a Traffic Management Initiative (TMI) intended to control the air traffic flow rates at multiple specified Flow Constrained Areas (FCAs), where demand exceeds capacity. CTOP allows flight operators to submit the desired Trajectory Options Set (TOS) for each affected flight with associated Relative Trajectory Cost (RTC) for each option. CTOP then creates a feasible schedule that complies with capacity constraints by assigning affected flights with routes and departure delays in such a way as to minimize the total cost while maintaining equity across flight operators. The current version of CTOP implements a Ration-by-Schedule (RBS) scheme, which assigns the best available options to flights based on a First-Scheduled-First-Served heuristic. In the present study, an alternative flight scheduling approach is developed based on linear optimization. Results suggest that such an approach can significantly reduce flight delays, in the deterministic case, while maintaining equity as defined using a Max-Min fairness scheme.

  8. 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.

  9. Trajectory phases of a quantum dot model

    International Nuclear Information System (INIS)

    Genway, Sam; Hickey, James M; Garrahan, Juan P; Armour, Andrew D

    2014-01-01

    We present a thermodynamic formalism to study the trajectories of charge transport through a quantum dot coupled to two leads in the resonant-level model. We show that a close analogue of equilibrium phase transitions exists for the statistics of transferred charge; by tuning an appropriate ‘counting field’, crossovers to different trajectory phases are possible. Our description reveals a mapping between the statistics of a given device and current measurements over a range of devices with different dot–lead coupling strengths. Furthermore insight into features of the trajectory phases are found by studying the occupation of the dot conditioned on the transported charge between the leads; this is calculated from first principles using a trajectory biased two-point projective measurement scheme. (paper)

  10. 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.

  11. Trajectory Stability in the Traveling Salesman Problem

    Directory of Open Access Journals (Sweden)

    Sergio Sánchez

    2018-01-01

    Full Text Available Two generalizations of the traveling salesman problem in which sites change their position in time are presented. The way the rank of different trajectory lengths changes in time is studied using the rank diversity. We analyze the statistical properties of rank distributions and rank dynamics and give evidence that the shortest and longest trajectories are more predictable and robust to change, that is, more stable.

  12. Modelling environmentally friendly fairways using Lagrangian trajectories: a case study for the Gulf of Finland, the Baltic Sea

    Science.gov (United States)

    Soomere, Tarmo; Berezovski, Mihhail; Quak, Ewald; Viikmäe, Bert

    2011-10-01

    We address possibilities of minimising environmental risks using statistical features of current-driven propagation of adverse impacts to the coast. The recently introduced method for finding the optimum locations of potentially dangerous activities (Soomere et al. in Proc Estonian Acad Sci 59:156-165, 2010) is expanded towards accounting for the spatial distributions of probabilities and times for reaching the coast for passively advecting particles released in different sea areas. These distributions are calculated using large sets of Lagrangian trajectories found from Eulerian velocity fields provided by the Rossby Centre Ocean Model with a horizontal resolution of 2 nautical miles for 1987-1991. The test area is the Gulf of Finland in the northeastern Baltic Sea. The potential gain using the optimum fairways from the Baltic Proper to the eastern part of the gulf is an up to 44% decrease in the probability of coastal pollution and a similar increase in the average time for reaching the coast. The optimum fairways are mostly located to the north of the gulf axis (by 2-8 km on average) and meander substantially in some sections. The robustness of this approach is quantified as the typical root mean square deviation (6-16 km) between the optimum fairways specified from different criteria. Drastic variations in the width of the `corridors' for almost optimal fairways (2-30 km for the average width of 15 km) signifies that the sensitivity of the results with respect to small changes in the environmental criteria largely varies in different parts of the gulf.

  13. Phylogenetic and CRISPR/Cas9 Studies in Deciphering the Evolutionary Trajectory and Phenotypic Impacts of Rice ERECTA Genes

    Directory of Open Access Journals (Sweden)

    Yanchun Zhang

    2018-04-01

    Full Text Available The ERECTA family genes (ERfs have been found to play diverse functions in Arabidopsis, including controlling cell proliferation and cell growth, regulating stomata patterning, and responding to various stresses. This wide range of functions has rendered them as a potential candidate for crop improvement. However, information on their functional roles, particularly their morphological impact, in crop genomes, such as rice, is limited. Here, through evolutionary prediction, we first depict the evolutionary trajectory of the ER family, and show that the ER family is actually highly conserved across different species, suggesting that most of their functions may also be observed in other plant species. We then take advantage of the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats–associated nuclease 9 system to assess their morphological impact on one of the most important crops, rice. Loss-of-function mutants of OsER1 and OsER2 display shortened plant stature and reduced panicle size, suggesting they possibly also functioned in regulating cell proliferation and cell growth in rice. In addition to functions similar to that in Arabidopsis, we also find clues that rice ERfs may play unique functional roles. The OsER2 displayed more severe phenotypic changes than OsER1, indicating putative differentiation in their functions. The OsERL might be of essential in its function, and the proper function of all three rice ER genes might be dependent of their genetic background. Future investigations relating to these functions are key to exploiting ERfs in crop development.

  14. Trajectories of income and social benefits for mothers and fathers of children with cancer: A national cohort study in Sweden.

    Science.gov (United States)

    Hiyoshi, Ayako; Montgomery, Scott; Bottai, Matteo; Hovén, Emma I

    2018-04-01

    The contribution of different income sources from work and social benefits to trajectories of income for the parents of children with cancer has not been empirically investigated. Using Swedish registers, parents of children with an incidence cancer diagnosis between 2004 and 2009 were identified and matched with parents of children without cancer (reference parents). A total of 20,091 families were followed from the year before the diagnosis to a maximum of 8 years. Generalized linear models estimated the ratios of mean incomes from work and social benefits and of its total. Around the time of the child's cancer diagnosis, the total income was on average up to 6% higher among the mothers of children with cancer compared with reference mothers, but no differences were noted among fathers. Income from work dropped to the lowest level around the time of a cancer diagnosis, with swift recovery noted for fathers but not for mothers. Sickness and childcare-related benefits were up to 6 times larger for the parents of children with cancer than reference parents. As social benefits diminished after approximately 3 years, the total income of mothers of children with cancer became lower than that of reference mothers, and the gap widened over time. Social benefits appeared to ease the financial burden during the years around a cancer diagnosis. However, mothers experienced persistently lower income after benefits diminished. Experiences differed by single-parent versus dual-parent households, the survival of the child with cancer, and other relevant characteristics. Further investigation is needed for potential long-term consequences for mothers, including their career and future pension in retirement. Cancer 2018;124:1492-500. © 2018 American Cancer Society. © 2018 American Cancer Society.

  15. Trajectory similarity join in spatial networks

    KAUST Repository

    Shang, Shuo; Chen, Lisi; Wei, Zhewei; Jensen, Christian S.; Zheng, Kai; Kalnis, Panos

    2017-01-01

    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.

  16. Quasiclassical calculation of the quasiparticle thermal conductivity in a mixed state

    International Nuclear Information System (INIS)

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

    2007-01-01

    We report the result of calculation of the quasiparticle thermal conductivity κ xx (∇T orthogonal B) in the vortex state of a two-dimensional superconductor. We compute κ 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 κ xx based on the BPT method is slightly underestimated due to its incoherent spatial averaging procedure

  17. Flash trajectory imaging of target 3D motion

    Science.gov (United States)

    Wang, Xinwei; Zhou, Yan; Fan, Songtao; He, Jun; Liu, Yuliang

    2011-03-01

    We present a flash trajectory imaging technique which can directly obtain target trajectory and realize non-contact measurement of motion parameters by range-gated imaging and time delay integration. Range-gated imaging gives the range of targets and realizes silhouette detection which can directly extract targets from complex background and decrease the complexity of moving target image processing. Time delay integration increases information of one single frame of image so that one can directly gain the moving trajectory. In this paper, we have studied the algorithm about flash trajectory imaging and performed initial experiments which successfully obtained the trajectory of a falling badminton. Our research demonstrates that flash trajectory imaging is an effective approach to imaging target trajectory and can give motion parameters of moving targets.

  18. 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.

  19. Differences and similarities in the trajectories of self-esteem and positive and negative affect in persons with chronic illness: an explorative longitudinal study

    Science.gov (United States)

    Bonsaksen, Tore; Lerdal, Anners; Småstuen, Milada Cvancarova; Fagermoen, May Solveig

    2016-01-01

    Background Chronic illness is a risk factor for low self-esteem, and the research literature needs to include more studies of self-esteem and its development in chronic illness groups using longitudinal and comparative designs. The aim of this study was to explore the trajectories of self-esteem and of positive and negative affect in persons with morbid obesity and in persons with chronic obstructive pulmonary disease (COPD). Methods Patient education course attendants in Norway having morbid obesity (n=139) or COPD (n=97) participated in the study. Data concerning self-esteem, positive and negative affect, and sociodemographic background were collected at the start and at the end of the patient education, with subsequent follow-ups at 3, 6, and 12 months. Data were analyzed using linear mixed models for repeated measures. Results Taking all measurements into account, our data revealed a statistically significant increase in self-esteem for participants with morbid obesity but not for those with COPD. There were no significant differences in levels of negative and positive affect between the two groups, and the time-trajectories were also similar. However, participants in both groups achieved lower levels of negative affect for all the successive measurement points. Conclusion An increase in self-esteem during the first year after the patient education course was observed for persons with morbid obesity, but not for persons with COPD. Initial higher levels of self-esteem in the participants with COPD may indicate that they are less troubled with low self-esteem than people with morbid obesity are. The pattern of reduced negative affect for both groups during follow-up is promising. PMID:27574438

  20. Differences and similarities in the trajectories of self-esteem and positive and negative affect in persons with chronic illness: an explorative longitudinal study.

    Science.gov (United States)

    Bonsaksen, Tore; Lerdal, Anners; Småstuen, Milada Cvancarova; Fagermoen, May Solveig

    2016-01-01

    Chronic illness is a risk factor for low self-esteem, and the research literature needs to include more studies of self-esteem and its development in chronic illness groups using longitudinal and comparative designs. The aim of this study was to explore the trajectories of self-esteem and of positive and negative affect in persons with morbid obesity and in persons with chronic obstructive pulmonary disease (COPD). Patient education course attendants in Norway having morbid obesity (n=139) or COPD (n=97) participated in the study. Data concerning self-esteem, positive and negative affect, and sociodemographic background were collected at the start and at the end of the patient education, with subsequent follow-ups at 3, 6, and 12 months. Data were analyzed using linear mixed models for repeated measures. Taking all measurements into account, our data revealed a statistically significant increase in self-esteem for participants with morbid obesity but not for those with COPD. There were no significant differences in levels of negative and positive affect between the two groups, and the time-trajectories were also similar. However, participants in both groups achieved lower levels of negative affect for all the successive measurement points. An increase in self-esteem during the first year after the patient education course was observed for persons with morbid obesity, but not for persons with COPD. Initial higher levels of self-esteem in the participants with COPD may indicate that they are less troubled with low self-esteem than people with morbid obesity are. The pattern of reduced negative affect for both groups during follow-up is promising.

  1. Semantic Enrichment of GPS Trajectories

    NARCIS (Netherlands)

    de Graaff, V.; van Keulen, Maurice; de By, R.A.

    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

  2. Optimizing interplanetary trajectories with deep space maneuvers

    Science.gov (United States)

    Navagh, John

    1993-09-01

    Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

  3. 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.

  4. Searching Trajectories by Regions of Interest

    KAUST Repository

    Shang, Shuo; chen, Lisi; Jensen, Christian S.; Wen, Ji-Rong; Kalnis, Panos

    2017-01-01

    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.

  5. Electron trajectory program

    International Nuclear Information System (INIS)

    Herrmannsfeldt, W.B.

    1979-11-01

    The SLAC Electron Trajectory Program is described and instructions and examples for users are given. The program is specifically written to compute trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes. Either rectangular or cylindrically symmetric geometry may be used. Magntic fields may be specified using arbitrary configurations of coils, or the output of a magnet program such as Poisson or by an externally calculated array of the axial fields. The program is available in IBM FORTRAN but can be easily converted for use on other brands of hardware. The program is intended to be used with a plotter whose interface the user must provide

  6. Electron trajectory program

    Energy Technology Data Exchange (ETDEWEB)

    Herrmannsfeldt, W.B.

    1979-11-01

    The SLAC Electron Trajectory Program is described and instructions and examples for users are given. The program is specifically written to compute trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes. Either rectangular or cylindrically symmetric geometry may be used. Magntic fields may be specified using arbitrary configurations of coils, or the output of a magnet program such as Poisson or by an externally calculated array of the axial fields. The program is available in IBM FORTRAN but can be easily converted for use on other brands of hardware. The program is intended to be used with a plotter whose interface the user must provide.

  7. Sleep Duration Trajectories and Systemic Inflammation in Young Adults: Results From the National Longitudinal Study of Adolescent to Adult Health (Add Health).

    Science.gov (United States)

    Bakour, Chighaf; Schwartz, Skai; O'Rourke, Kathleen; Wang, Wei; Sappenfield, William; Couluris, Marisa; Chen, Henian

    2017-11-01

    This study examines the effects of short and long sleep duration patterns in young adults on the levels of C-reactive protein (CRP), as well as the potential effect modification by sex. Using data from waves III (age 18-26) and IV (age 24-32) of the National Longitudinal study of adolescent to adult health, we examined the association between sleep trajectories in young adults, and the risk of elevated high sensitivity-CRP (hs-CRP), a marker of systemic inflammation. Short sleep trajectories were associated with significantly elevated log-transformed hs-CRP (coefficient = 0.11, p-value .03) and with significantly higher odds of having hs-CRP levels > 3 mg/L (OR = 1.86, 95% CI 1.29, 2.67). The association was modified by sex, with the association between short sleep duration and hs-CRP limited to males. Both the continuous (coefficient 0.117, p-value = .0362) and the categorized hs-CRP (OR = 2.21, 95% CI 1.48, 3.30) were significantly elevated with short sleep durations in males, whereas no significant associations were seen in females with short sleep durations. By contrast, log hs-CRP was significantly elevated in females with long sleep durations (coefficient = 0.232, p-value = .0296), with a nonsignificant increase in the odds of having hs-CRP levels greater than 3 mg/L (OR = 1.48, 95% CI 0.75, 2.93), whereas there were no associations with long sleep duration in males. Systemic inflammation, measured by an elevated level of hs-CRP, is seen with persistent short sleep duration in young adult men and persistent long sleep duration in young adult women. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  8. Outcome of older persons admitted to intensive care unit, mortality, prognosis factors, dependency scores and ability trajectory within 1 year: a prospective cohort study.

    Science.gov (United States)

    Level, Claude; Tellier, Eric; Dezou, Patrick; Chaoui, Karim; Kherchache, Aissa; Sejourné, Philippe; Rullion-Pac Soo, Anne Marie

    2017-12-06

    The outcome and functional trajectory of older persons admitted to intensive care (ICU) unit remain a true question for critical care physicians and geriatricians, due to the heterogeneity of geriatric population, heterogeneity of practices and absence of guidelines. To describe the 1-year outcome, prognosis factors and functional trajectory for older people admitted to ICU. In a prospective 1-year cohort study, all patients aged 75 years and over admitted to our ICU were included according to a global comprehensive geriatric assessment. Follow-up was conducted for 1 year survivors, in particular, ability scores and living conditions. Of 188 patients included [aged 82.3 ± 4.7 years, 46% of admissions, median SAPS II 53.5 (43-74), ADL of Katz's score 4.2 ± 1.6, median Barthel's index 71 (55-90), AGGIR scale 4.5 ± 1.5], the ICU, hospital and 1-year mortality were, respectively, 34, 42.5 and 65.5%. Prognosis factors were: SAPS 2, mechanical ventilation, comorbidity (Lee's and Mc Cabe's scores), disability scores (ADL of Katz's score, Barthel's index and AGGIR scale), admission creatinin, hypoalbuminemia, malignant haemopathy, cognitive impairment. One-year survivors lived in their own home for 83%, with a preserved physical ability, without significant variation of the three ability assessed scores compared to prior ICU admission. The mortality of older people admitted to ICU is high, with a significant impact of disabilty scores, and preserved 1-year survivor independency. Other studies, including a better comprehensive geriatric assessment, seem necessary to determine a predictive "phenotype" of survival with a "satisfactory" level of autonomy.

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

    Science.gov (United States)

    Wiium, Nora; Breivik, Kyrre; Wold, Bente

    2015-10-28

    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.

  10. 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.

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

    Science.gov (United States)

    Wiium, Nora; Breivik, Kyrre; Wold, Bente

    2015-01-01

    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. PMID:26516889

  12. Synthetic triphones from trajectory-based feature distributions

    CSIR Research Space (South Africa)

    Badenhorst, J

    2015-11-01

    Full Text Available we reconstruct models for unseen transitions. In the current study, we restrict ourselves to triphone modelling, and aim to generate synthetic triphones from seen diphones. If this is possible, the same approach should be applicable to larger contexts... are applied in a similar fashion. Using trajectory models for the same goal, builds on prior work analysing co-articulation trajectories [7], [8], [9] as well as various studies on trajectory modelling for ASR purposes [10], [11], [12], [13]. Particularly...

  13. Differences and similarities in the trajectories of self-esteem and positive and negative affect in persons with chronic illness: an explorative longitudinal study

    Directory of Open Access Journals (Sweden)

    Bonsaksen T

    2016-08-01

    Full Text Available Tore Bonsaksen,1 Anners Lerdal,2,3 Milada Cvancarova Småstuen,4 May Solveig Fagermoen3 1Department of Occupational Therapy, Prosthetics and Orthotics, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, Oslo, Norway; 2Research Department, Lovisenberg Diakonale Hospital, Oslo, Norway; 3Department of Nursing Science, Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway; 4Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, Oslo, Norway Background: Chronic illness is a risk factor for low self-esteem, and the research literature needs to include more studies of self-esteem and its development in chronic illness groups using longitudinal and comparative designs. The aim of this study was to explore the trajectories of self-esteem and of positive and negative affect in persons with morbid obesity and in persons with chronic obstructive pulmonary disease (COPD.Methods: Patient education course attendants in Norway having morbid obesity (n=139 or COPD (n=97 participated in the study. Data concerning self-esteem, positive and negative affect, and sociodemographic background were collected at the start and at the end of the patient education, with subsequent follow-ups at 3, 6, and 12 months. Data were analyzed using linear mixed models for repeated measures.Results: Taking all measurements into account, our data revealed a statistically significant increase in self-esteem for participants with morbid obesity but not for those with COPD. There were no significant differences in levels of negative and positive affect between the two groups, and the time-trajectories were also similar. However, participants in both groups achieved lower levels of negative affect for all the successive measurement points.Conclusion: An increase in self-esteem during the first year after the patient education course was observed

  14. Advancing nursing science through health trajectory research: an introduction.

    Science.gov (United States)

    Wyman, Jean F; Henly, Susan J

    2011-01-01

    The Minnesota Center for Health Trajectory Research has focused on developing ways to better understand how interventions influence health trajectories during transitional, acute, or chronic health challenges across the life span. The health trajectory perspective advances nursing science by providing a person-centered point of view that emphasizes change in health over time within individuals, families, groups, or communities. Theoretical considerations and statistical modeling approaches used in studying health trajectories, along with exemplars from nursing research studies from this special issue of Nursing Research, are highlighted.

  15. Zero-point energy conservation in classical trajectory simulations: Application to H2CO

    Science.gov (United States)

    Lee, Kin Long Kelvin; Quinn, Mitchell S.; Kolmann, Stephen J.; Kable, Scott H.; Jordan, Meredith J. T.

    2018-05-01

    A new approach for preventing zero-point energy (ZPE) violation in quasi-classical trajectory (QCT) simulations is presented and applied to H2CO "roaming" reactions. Zero-point energy may be problematic in roaming reactions because they occur at or near bond dissociation thresholds and these channels may be incorrectly open or closed depending on if, or how, ZPE has been treated. Here we run QCT simulations on a "ZPE-corrected" potential energy surface defined as the sum of the molecular potential energy surface (PES) and the global harmonic ZPE surface. Five different harmonic ZPE estimates are examined with four, on average, giving values within 4 kJ/mol—chemical accuracy—for H2CO. The local harmonic ZPE, at arbitrary molecular configurations, is subsequently defined in terms of "projected" Cartesian coordinates and a global ZPE "surface" is constructed using Shepard interpolation. This, combined with a second-order modified Shepard interpolated PES, V, allows us to construct a proof-of-concept ZPE-corrected PES for H2CO, Veff, at no additional computational cost to the PES itself. Both V and Veff are used to model product state distributions from the H + HCO → H2 + CO abstraction reaction, which are shown to reproduce the literature roaming product state distributions. Our ZPE-corrected PES allows all trajectories to be analysed, whereas, in previous simulations, a significant proportion was discarded because of ZPE violation. We find ZPE has little effect on product rotational distributions, validating previous QCT simulations. Running trajectories on V, however, shifts the product kinetic energy release to higher energy than on Veff and classical simulations of kinetic energy release should therefore be viewed with caution.

  16. 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…

  17. Signatures of unstable semiclassical trajectories in tunneling

    International Nuclear Information System (INIS)

    Levkov, D G; Panin, A G; Sibiryakov, S M

    2009-01-01

    It was found recently that processes of multidimensional tunneling are generally described at high energies by unstable semiclassical trajectories. We study two observational signatures related to the instability of trajectories. First, we find an additional power-law dependence of the tunneling probability on the semiclassical parameter as compared to the standard case of potential tunneling. The second signature is a substantial widening of the probability distribution over final-state quantum numbers. These effects are studied using a modified semiclassical technique which incorporates stabilization of the tunneling trajectories. The technique is derived from first principles. We obtain expressions for the inclusive and exclusive tunneling probabilities in the case of unstable semiclassical trajectories. We also investigate the 'phase transition' between the cases of stable and unstable trajectories across certain 'critical' values of energy. Finally, we derive the relation between the semiclassical probabilities of tunneling from the low-lying and highly excited initial states. This puts on firm ground a conjecture made previously in the semiclassical description of collision-induced tunneling in field theory

  18. Trajectory attractors of equations of mathematical physics

    International Nuclear Information System (INIS)

    Vishik, Marko I; Chepyzhov, Vladimir V

    2011-01-01

    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.

  19. GeoTravel: Harvesting Ambient Geographic Footprints from GPS Trajectories

    OpenAIRE

    Liew, Li Ching; Goh, Ong Sing

    2014-01-01

    This study is about harvesting point of interest from GPS trajectories. Trajectories are the paths that moving objects move by follow through space in a function of time while GPS trajectories generally are point-sequences with geographic coordinates, time stamp, speed and heading. User can get information from GPS enable device. For example, user can acquire present location, search the information around them and design driving routes to a destination and thus design travel itineraries. By ...

  20. Trajectory optimization using indirect methods and parametric scramjet cycle analysis

    OpenAIRE

    Williams, Joseph

    2016-01-01

    This study investigates the solution of time sensitive regional strike trajectories for hypersonic missiles. This minimum time trajectory is suspected to be best performed by scramjet powered hypersonic missiles which creates strong coupled interaction between the flight dynamics and the performance of the engine. Comprehensive engine models are necessary to gain better insight into scramjet propulsion. Separately, robust and comprehensive trajectory analysis provides references for vehicles ...

  1. Moyal dynamics and trajectories

    Science.gov (United States)

    Braunss, G.

    2010-01-01

    We give first an approximation of the operator δh: f → δhf := h*planckf - f*planckh in terms of planck2n, n >= 0, where h\\equiv h(p,q), (p,q)\\in {\\mathbb R}^{2 n} , is a Hamilton function and *planck denotes the star product. The operator, which is the generator of time translations in a *planck-algebra, can be considered as a canonical extension of the Liouville operator Lh: f → Lhf := {h, f}Poisson. Using this operator we investigate the dynamics and trajectories of some examples with a scheme that extends the Hamilton-Jacobi method for classical dynamics to Moyal dynamics. The examples we have chosen are Hamiltonians with a one-dimensional quartic potential and two-dimensional radially symmetric nonrelativistic and relativistic Coulomb potentials, and the Hamiltonian for a Schwarzschild metric. We further state a conjecture concerning an extension of the Bohr-Sommerfeld formula for the calculation of the exact eigenvalues for systems with classically periodic trajectories.

  2. Developmental trajectories of bullying and associated factors.

    Science.gov (United States)

    Pepler, Debra; Jiang, Depeng; Craig, Wendy; Connolly, Jennifer

    2008-01-01

    Trajectories in bullying through adolescence were studied along with individual, family, and peer relationship factors. At the outset, participants' ages ranged from 10 to 14; 74% identified as European Canadian with the remainder from diverse backgrounds. With 8 waves of data over 7 years, 871 students (466 girls and 405 boys) were studied to reveal 4 trajectories: 9.9% reported consistently high levels of bullying, 13.4% reported early moderate levels desisting to almost no bullying at the end of high school, 35.1% reported consistently moderate levels, and 41.6% almost never reported bullying. Students who bullied had elevated risks in individual, parent, and peer relationship domains. Risk profiles and trajectories provide direction for interventions to curtail the development of power and aggression in relationships.

  3. Canonical transformations of Kepler trajectories

    International Nuclear Information System (INIS)

    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 transformations change the eccentricity of the orbit. A method of obtaining elliptic trajectories from the circular ones with the help of canonical trajectories is discussed.

  4. Handling Trajectory Uncertainties for Airborne Conflict Management

    Science.gov (United States)

    Barhydt, Richard; Doble, Nathan A.; Karr, David; Palmer, Michael T.

    2005-01-01

    Airborne conflict management is an enabling capability for NASA's Distributed Air-Ground Traffic Management (DAG-TM) concept. DAGTM has the goal of significantly increasing capacity within the National Airspace System, while maintaining or improving safety. Under DAG-TM, autonomous aircraft maintain separation from each other and from managed aircraft unequipped for autonomous flight. NASA Langley Research Center has developed the Autonomous Operations Planner (AOP), an onboard decision support system that provides airborne conflict management (ACM) and strategic flight planning support for autonomous aircraft pilots. The AOP performs conflict detection, prevention, and resolution from nearby traffic aircraft and area hazards. Traffic trajectory information is assumed to be provided by Automatic Dependent Surveillance Broadcast (ADS-B). Reliable trajectory prediction is a key capability for providing effective ACM functions. Trajectory uncertainties due to environmental effects, differences in aircraft systems and performance, and unknown intent information lead to prediction errors that can adversely affect AOP performance. To accommodate these uncertainties, the AOP has been enhanced to create cross-track, vertical, and along-track buffers along the predicted trajectories of both ownship and traffic aircraft. These buffers will be structured based on prediction errors noted from previous simulations such as a recent Joint Experiment between NASA Ames and Langley Research Centers and from other outside studies. Currently defined ADS-B parameters related to navigation capability, trajectory type, and path conformance will be used to support the algorithms that generate the buffers.

  5. Neighbourhood effects as indirect effects: evidence from a Dutch case study on the significance of neighbourhood for employment trajectories

    NARCIS (Netherlands)

    Pinkster, F.M.

    2014-01-01

    One of the key challenges in the study of neighbourhood effects on work is to understand the pathways through which disadvantaged neighbourhoods impact the employment opportunities of residents. Endogenous explanations for neighbourhood effects focus on social life in these neighbourhoods,

  6. The impact of the refugee decision on the trajectory of PTSD, anxiety, and depressive symptoms among asylum seekers: a longitudinal study.

    Science.gov (United States)

    Silove, Derrick; Steel, Zachary; Susljik, Ina; Frommer, Naomi; Loneragan, Celia; Chey, Tien; Brooks, Robert; le Touze, Dominique; Ceollo, Mariano; Smith, Mitchell; Harris, Elizabeth; Bryant, Richard

    2007-01-01

    To examine prospectively the trajectory of trauma-related psychiatric symptoms and disability amongst asylum seekers over the course of the refugee determination process. To identify the direct impact of the refugee decision on psychiatric symptoms by adjusting for other variables, namely sociodemographic characteristics, past trauma, and ongoing postmigration stresses. A prospective cohort study of asylum seekers recruited from a random sample of immigration agents in Sydney, Australia. Consecutive asylum seekers were referred for interview by immigration agents. Interviews were undertaken after the initial application and on average, 3.8 months after the refugee decision. Measures assessed premigration trauma and postmigration stressors. Mental health status was assessed using the Harvard Trauma Questionnaire and the Hopkins Symptom Checklist-25. Functional impairment was assessed with the Medical Outcomes Study-Short Form 12. Sixty-two of 73 asylum seekers were retained at follow-up. The accepted (16) and rejected (46) groups did not differ on premigration trauma or baseline psychiatric symptoms. Postdecision, the accepted group showed substantial improvements in posttraumatic stress disorder, anxiety, depression, and in mental health functioning, whereas the rejected group maintained high levels of symptoms on all psychiatric indices. Establishing secure residency status for asylum seekers may be important to their recovery from trauma-related psychiatric symptoms. The practical and theoretical implications are discussed.

  7. Mining of hospital laboratory information systems: a model study defining age- and gender-specific reference intervals and trajectories for plasma creatinine in a pediatric population.

    Science.gov (United States)

    Søeby, Karen; Jensen, Peter Bjødstrup; Werge, Thomas; Sørensen, Steen

    2015-09-01

    The knowledge of physiological fluctuation and variation of even commonly used biochemical quantities in extreme age groups and during development is sparse. This challenges the clinical interpretation and utility of laboratory tests in these age groups. To explore the utility of hospital laboratory data as a source of information, we analyzed enzymatic plasma creatinine as a model analyte in two large pediatric hospital samples. Plasma creatinine measurements from 9700 children aged 0-18 years were obtained from hospital laboratory databases and partitioned into high-resolution gender- and age-groups. Normal probability plots were used to deduce parameters of the normal distributions from healthy creatinine values in the mixed hospital datasets. Furthermore, temporal trajectories were generated from repeated measurements to examine developmental patterns in periods of changing creatinine levels. Creatinine shows great age dependence from birth throughout childhood. We computed and replicated 95% reference intervals in narrow gender and age bins and showed them to be comparable to those determined in healthy population studies. We identified pronounced transitions in creatinine levels at different time points after birth and around the early teens, which challenges the establishment and usefulness of reference intervals in those age groups. The study documents that hospital laboratory data may inform on the developmental aspects of creatinine, on periods with pronounced heterogeneity and valid reference intervals. Furthermore, part of the heterogeneity in creatinine distribution is likely due to differences in biological and chronological age of children and should be considered when using age-specific reference intervals.

  8. 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

  9. 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.

  10. 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

  11. Disability Trajectories in Patients With Complaints of Arm, Neck, and Shoulder (CANS) in Primary Care : Prospective Cohort Study

    NARCIS (Netherlands)

    Miedema, Harald S; Feleus, Anita; Bierma-Zeinstra, Sita M. A.; Hoekstra, T.; Burdorf, Alex; Koes, Bart W

    BACKGROUND: Nontraumatic complaints of arm, neck, and shoulder (CANS) represent an important health issue, with a high prevalence in the general working age population and huge economic impact. Nevertheless, only few prospective cohort studies for the outcome of CANS are available. OBJECTIVES: The

  12. 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

  13. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Quantum trajectory phase transitions in the micromaser.

    Science.gov (United States)

    Garrahan, Juan P; Armour, Andrew D; Lesanovsky, Igor

    2011-08-01

    We study the dynamics of the single-atom maser, or micromaser, by means of the recently introduced method of thermodynamics of quantum jump trajectories. We find that the dynamics of the micromaser displays multiple space-time phase transitions, i.e., phase transitions in ensembles of quantum jump trajectories. This rich dynamical phase structure becomes apparent when trajectories are classified by dynamical observables that quantify dynamical activity, such as the number of atoms that have changed state while traversing the cavity. The space-time transitions can be either first order or continuous, and are controlled not just by standard parameters of the micromaser but also by nonequilibrium "counting" fields. We discuss how the dynamical phase behavior relates to the better known stationary-state properties of the micromaser.

  15. The life trajectories modality of oral history

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Gonçalves

    2007-05-01

    Full Text Available This article seeks to explore the potential of qualitative research. It presents the life trajectory modality of the oral history method, to discuss the possibility of its utilization in scientific research in the Social Work profession. The epistemological foundations of oral history are discussed to establish its scientific character. The life trajectories modality is presented as a historic and social construction that utilizes different interview techniques to give voice to previously invisible subjects, indicating the principal phases of the methodological procedures used in this approach. The conclusions highlight the importance of the construction of this model and its projection as a research proposal that implies a process of understanding and analyzing the social universes that are contextualized and interconnected, considering the realities of the life trajectories of the subjects studied.

  16. 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...... obtained due to hardware limitations of measuring devices, as well as the constantly-changing nature of the external environment. Ignoring data uncertainty can render low query quality, and cause undesirable consequences such as missing alerts of threats and poor response time in rescue operations. Also......, 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...

  17. 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…

  18. 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…

  19. 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…

  20. Trajectory Based Traffic Analysis

    DEFF Research Database (Denmark)

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

    2013-01-01

    We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a......We present the INTRA system for interactive path-based traffic analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point......-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...

  1. 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...

  2. Trajectories of mental health problems in children of parents with mental health problems: results of the BELLA study.

    Science.gov (United States)

    Plass-Christl, Angela; Otto, Christiane; Klasen, Fionna; Wiegand-Grefe, Silke; Barkmann, Claus; Hölling, Heike; Schulte-Markwort, Michael; Ravens-Sieberer, Ulrike

    2017-11-24

    Children of parents with mental health problems (CPM) have an increased risk for behavioral and psychological problems. This study investigated the age- and gender-specific course as well as predictors of mental health problems in CPM using the longitudinal data (baseline 1- and 2-year follow-ups) of a German general population sample from the BELLA study. Children and adolescents aged 11-17 years (at baseline) who had a parent with mental health problems (n = 325) were analyzed. The mental health problems of the children were assessed by the self-reported version of the strengths and difficulties questionnaire (SDQ). We used individual growth modeling to investigate the age- and gender-specific course, and the effects of risk as well as personal, familial and social protective factors on self-reported mental health problems in CPM. Additionally, data were examined differentiating internalizing and externalizing mental health problems in CPM. Results indicated that female compared to male CPM showed increasing mental health problems with increasing age. Mental health problems in CPM were associated with lower self-efficacy, worse family climate and less social competence over time. Internalizing problems were associated with lower self-efficacy, less social competence and more severe parental mental health problems. Externalizing problems were associated with lower self-efficacy, worse family climate and lower social competence. The main limitations of the study are the short time period (2 years) covered and the report of mental health problems by only one parent. Our findings should be considered in the development of treatment and prevention programs for mental health problems in CPM.

  3. DESTINY+ Trajectory Design to (3200) Phaethon

    Science.gov (United States)

    Sarli, Bruno Victorino; Horikawa, Makoto; Yam, Chit Hong; Kawakatsu, Yasuhiro; Yamamoto, Takayuki

    2018-03-01

    This work explores the target selection and trajectory design of the mission candidate for ISAS/JAXA's small science satellite series, DESTINY PLUS or DESTINY+. This mission combines unique aspects of the latest satellite technology and exploration of transition bodies to fill a technical and scientific gap in the Japanese space science program. The spacecraft is targeted to study the comet-asteroid transition body (3200) Phaethon through a combination of low-thrust propulsion and Earth Gravity Assist. The trajectory design concept is presented in details together with the launch window and flyby date analysis. Alternative targets for a possible mission extension scenario are also explored.

  4. 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.

  5. Trajectory of intimate partner violence and healthcare seeking over the life course: study of Japanese women in the Tokyo metropolitan area, Japan.

    Science.gov (United States)

    Kamimura, A; Yoshihama, M; Bybee, D

    2013-10-01

    To describe the trajectory of, and examine factors affecting, intimate partner violence (IPV) and IPV-specific healthcare seeking among Japanese women over the life course. Life course study. One hundred and one women, aged 24-80 years, who had a lifetime history of IPV were interviewed in the Tokyo metropolitan area, Japan in 2005 and 2006. Life course data were collected according to the life history calendar method. Hierarchical linear modelling was used to examine IPV-specific healthcare seeking over the life course. Injury, formal or informal help seeking, public assistance, worse self-rated health status and smoking significantly increased the likelihood of IPV-specific healthcare seeking over the life course. There are significant cohort effects on healthcare seeking. The results suggest that women who experience IPV may seek healthcare services not only immediately after the first occurrence of IPV, but also later in life. IPV is not always associated with immediate healthcare seeking. In particular, sexual IPV is not significantly associated with healthcare seeking. Pursuing formal and informal help is associated with healthcare seeking. Copyright © 2013 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  6. Trajectory of physical activity after hip fracture: An analysis of community-dwelling individuals from the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Aboelmagd, Tariq; Dainty, Jack R; MacGregor, Alex; Smith, Toby O

    2018-03-01

    To analyse physical activity participation in a community-dwelling people in England with hip fracture the interval prior to fracture, in the fracture recovery period, and a minimum of two years post-fracture. 215 individuals were identified from the English Longitudinal Study of Ageing cohort (2002-2014) who sustained a hip fracture following a fall and for whom data were available on physical activity participation relating to the period pre-fracture, within-fracture recovery phase and post-fracture (minimum of two years). Physical activity was assessed using the validated ELSA physical activity questionnaire. Prevalence of 'low' physical activity participation was calculated and multi-level modelling analyses were performed to explore physical activity trajectories over the follow-up phase, and whether age, depression, gender and frailty were associated with physical activity participation. Prevalence of low physical activity participation within two years prior to hip fracture was 16.7% (95% Confidence Intervals (CI): 11.6% to 21.8%). This increased at the final follow-up phase to 21.3% (95% CI: 15.1% to 27.6%). This was not a statistically significant change (P = 0.100). Age (P = 0.005) and frailty (P dwelling individuals. This contrasts with previous reports of reduced mobility post-hip fracture, suggesting that 'physical activity' and 'mobility' should be considered as separate outcomes in this population. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Racial disparities in the health benefits of educational attainment: a study of inflammatory trajectories among African American and white adults.

    Science.gov (United States)

    Fuller-Rowell, Thomas E; Curtis, David S; Doan, Stacey N; Coe, Christopher L

    2015-01-01

    The current study examined the prospective effects of educational attainment on proinflammatory physiology among African American and white adults. Participants were 1192 African Americans and 1487 whites who participated in Year 5 (mean [standard deviation] age = 30 [3.5] years), and Year 20 (mean [standard deviation] age = 45 [3.5]) of an ongoing longitudinal study. Initial analyses focused on age-related changes in fibrinogen across racial groups, and parallel analyses for C-reactive protein and interleukin-6 assessed at Year 20. Models then estimated the effects of educational attainment on changes in inflammation for African Americans and whites before and after controlling for four blocks of covariates: a) early life adversity, b) health and health behaviors at baseline, c) employment and financial measures at baseline and follow-up, and d) psychosocial stresses in adulthood. African Americans had larger increases in fibrinogen over time than whites (B = 24.93, standard error = 3.24, p educational attainment were weaker for African Americans than for whites (B = 10.11, standard error = 3.29, p = .002), and only 8% of this difference was explained by covariates. Analyses for C-reactive protein and interleukin-6 yielded consistent results. The effects of educational attainment on inflammation levels were stronger for white than for African American participants. Why African Americans do not show the same health benefits with educational attainment is an important question for health disparities research.

  8. Socioeconomic status and trajectory of overweight from birth to mid-childhood: the Early Childhood Longitudinal Study-Birth Cohort.

    Directory of Open Access Journals (Sweden)

    Jessica C Jones-Smith

    Full Text Available 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.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 Childhood Growth Standard reference mean; henceforth, "overweight/obesity" according to age, socioeconomic status, and race/ethnicity using generalized estimating equation models.The association between socioeconomic status and overweight/obesity varied significantly by race/ethnicity, but not by sex. Overweight/obesity was significantly associated with socioeconomic status among whites, Hispanics and Asians; the adjusted odds of overweight/obesity began to diverge according to SES after the first 9 months of life. By approximately 4 years, children with the highest SES had a significantly lower odds of overweight/obesity. SES was not significantly related to overweight/obesity among African Americans and American Indians during early childhood.Few studies have assessed the associations between SES and overweight/obesity within racial/ethnic groups in the US. We find that in contemporary, US-born children, SES was inversely associated with overweight/obesity among more racial/ethnic groups (whites, Hispanics, and Asians than previously reported.

  9. Predicting adolescent postpartum caregiving from trajectories of depression and anxiety prior to childbirth: A five year prospective study

    Science.gov (United States)

    Hipwell, Alison E.; Stepp, Stephanie D.; Moses-Kolko, Eydie L.; Xiong, Shuangyan; Paul, Elena; Merrick, Natalie; McClelland, Samantha; Verble, Danielle; Keenan, Kate

    2016-01-01

    Purpose Symptoms of depression and anxiety in pregnancy have been linked to later impaired caregiving. However, mood symptoms are often elevated in pregnancy and may reflect motherhood-specific concerns. In contrast, little is known about the effects of pre-pregnancy depression and anxiety on postpartum caregiving. Understanding these developmental risk factors is especially important when childbearing also occurs during adolescence. Methods The sample comprised 188 adolescent mothers (ages 12–19 years) who had participated in a longitudinal study since childhood. Mothers were observed in face-to-face interaction with the infant at 4 months postpartum, and caregiving behaviors (sensitivity, hostile-intrusive behavior and mental state talk) were coded independently. Data on self-reported depression and anxiety gathered in the five years prior to childbirth were drawn from the large-scale longitudinal study. Results Parallel process latent growth curve models revealed unique effects of distal anxiety and slow decline in anxiety over time on lower levels of maternal mental state talk after accounting for the overlap with depression symptom development. Depressive symptoms showed significant stability from distal measurement to the postpartum period, but only concurrent postpartum mood was associated with poorer quality of maternal speech. Conclusions The results highlight specific targets for well-timed preventive interventions with vulnerable dyads. PMID:26971266

  10. 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.

  11. Quasiclassical Studies of Eley-Rideal and Hot Atom Reactions on Surface: H(D)→D(H)+Cu(111)

    International Nuclear Information System (INIS)

    Vurdu, C.D.

    2004-01-01

    Randomly distributed hydrogen adsorbates on the surface of Cu(1 1 1) are used to form 0.50, 0.25 and 0.15 monolayers of coverages to simulate D(H)→H(D) + Cu(111) system at 30 K and 94 K surface temperatures. The interaction of this system is mimicked by a LEPS function which is parameterized by using the energy points which were calculated by a density-functional theory method and the generalized gradient approximation for the exchange-correlation energy for various configurations of one a,nd two hydrogen atoms on the Cu(111) surface. Our results on H 2 , D 2 , and HD formations via Eley-Redial and hot-atom mechanisms will be presented at these temperatures. Probabilities for the rotational, vibrational, total and translational energy distributions of the products are calculated. In addition traping onto the surface, inelastic reflection of the incident projectile and penetration of the adsorbate or projectile atom into the slab is analyzed. Hot-atom pathways for product formations are shown to make significant contributions

  12. Treatment and Control: A Qualitative Study of Older Mentally Ill Offenders' Perceptions on Their Detention and Care Trajectory.

    Science.gov (United States)

    De Smet, Stefaan; Van Hecke, Nele; Verté, Dominique; Broekaert, Eric; Ryan, Denis; Vandevelde, Stijn

    2015-08-01

    The life of older mentally ill offenders (OMIOs) is often characterized by successive periods of detention in correctional facilities, admissions to psychiatric services, and unsuccessful attempts to live independently. Through in-depth interviews, eight personal stories from OMIOs under supervision of the commission of social defence in Ghent (Belgium) were analyzed in the phenomenological research tradition. The results of the study reveal that OMIOs had more positive and less negative experiences in prison settings when compared with other institutional care settings. Independent living, unsurprisingly, is favored the most. This may be due to the fact that the latter option fosters personal competence, feelings of being useful, personal choices, and contact with the "outside" world. Even in later lifetime, a combined approach of risk assessment with improvement of well-being remains valuable to stimulate offender rehabilitation. Therefore, more research into concepts that could be used to support OMIOs needs further consideration. © The Author(s) 2014.

  13. 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,

  14. Cognitive function trajectories and their determinants in older people: 8 years of follow-up in the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Zaninotto, Paola; Batty, G David; Allerhand, Michael; Deary, Ian J

    2018-04-24

    Maintaining cognitive function is an important aspect of healthy ageing. In this study, we examined age trajectories of cognitive decline in a large nationally representative sample of older people in England. We explored the factors that influence such decline and whether these differed by gender. Latent growth curve modelling was used to explore age-specific changes, and influences on them, in an 8-year period in memory, executive function, processing speed and global cognitive function among 10 626 participants in the English Longitudinal Study of Ageing. We run gender-specific models with the following exposures: age, education, wealth, childhood socioeconomic status, cardiovascular disease, diabetes, physical function, body mass index, physical activity, alcohol, smoking, depression and dementia. After adjustment, women had significantly less decline than men in memory (0.011, SE 0.006), executive function (0.012, SE 0.006) and global cognitive function (0.016, SE 0.004). Increasing age and dementia predicted faster rates of decline in all cognitive function domains. Depression and alcohol consumption predicted decline in some cognitive function domains in men only. Poor physical function, physical inactivity and smoking were associated with faster rates of decline in specific cognitive domains in both men and women. For example, relative to study members who were physically active, the sedentary experienced greater declines in memory (women -0.018, SE 0.009) and global cognitive function (men -0.015, SE 0.007 and women -0.016, SE 0.007). The potential determinants of cognitive decline identified in this study, in particular modifiable risk factors, should be tested in the context of randomised controlled trials. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  15. Development of a Web Application: Recording Learners' Mouse Trajectories and Retrieving their Study Logs to Identify the Occurrence of Hesitation in Solving Word-Reordering Problems

    Directory of Open Access Journals (Sweden)

    Mitsumasa Zushi

    2014-04-01

    Full Text Available Most computer marking systems evaluate the results of the answers reached by learners without looking into the process by which the answers are produced, which will be insufficient to ascertain learners' understanding level because correct answers may well include lucky hunches, namely accidentally correct but not confident answers. In order to differentiate these lucky answers from confident correct ones, we have developed a Web application that can record mouse trajectories during the performance of tasks. Mathematical analyses of these trajectories have revealed that some parameters for mouse movements can be useful indicators to identify the occurrence of hesitation resulting from lack of knowledge or confidence in solving problems.

  16. OPTIMAL AIRCRAFT TRAJECTORIES FOR SPECIFIED RANGE

    Science.gov (United States)

    Lee, H.

    1994-01-01

    For an aircraft operating over a fixed range, the operating costs are basically a sum of fuel cost and time cost. While minimum fuel and minimum time trajectories are relatively easy to calculate, the determination of a minimum cost trajectory can be a complex undertaking. This computer program was developed to optimize trajectories with respect to a cost function based on a weighted sum of fuel cost and time cost. As a research tool, the program could be used to study various characteristics of optimum trajectories and their comparison to standard trajectories. It might also be used to generate a model for the development of an airborne trajectory optimization system. The program could be incorporated into an airline flight planning system, with optimum flight plans determined at takeoff time for the prevailing flight conditions. The use of trajectory optimization could significantly reduce the cost for a given aircraft mission. The algorithm incorporated in the program assumes that a trajectory consists of climb, cruise, and descent segments. The optimization of each segment is not done independently, as in classical procedures, but is performed in a manner which accounts for interaction between the segments. This is accomplished by the application of optimal control theory. The climb and descent profiles are generated by integrating a set of kinematic and dynamic equations, where the total energy of the aircraft is the independent variable. At each energy level of the climb and descent profiles, the air speed and power setting necessary for an optimal trajectory are determined. The variational Hamiltonian of the problem consists of the rate of change of cost with respect to total energy and a term dependent on the adjoint variable, which is identical to the optimum cruise cost at a specified altitude. This variable uniquely specifies the optimal cruise energy, cruise altitude, cruise Mach number, and, indirectly, the climb and descent profiles. If the optimum

  17. Lunar Cube Transfer Trajectory Options

    Science.gov (United States)

    Folta, David; Dichmann, Donald James; Clark, Pamela E.; Haapala, Amanda; Howell, Kathleen

    2015-01-01

    Numerous Earth-Moon trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many trajectory options can b e considered which have a wide range of transfer duration, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO) geostationary transfer orbits (GTO) and higher energy direct lunar transfer and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory.

  18. 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…

  19. Landscape and Heritage: trajectories and consequences

    DEFF Research Database (Denmark)

    Harvey, David

    2015-01-01

    supporting and often parallel endeavour of academic, policy and popular inquiry that explores the significance of landscape and heritage as meaningful categories of an emergent and processual nature. Despite such a parallel trajectory, however, the actual practices of landscape and heritage studies still...

  20. Type 2 diabetes, depressive symptoms and trajectories of cognitive decline in a national sample of community-dwellers: A prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Panayotes Demakakos

    Full Text Available We examined the individual and synergistic effects of type 2 diabetes and elevated depressive symptoms on memory and executive function trajectories over 10 and eight years of follow-up, respectively. Our sample comprised 10,524 community-dwellers aged ≥50 years in 2002-03 from the English Longitudinal Study of Ageing. With respect to memory (word recall, participants with either diabetes or elevated depressive symptoms recalled significantly fewer words compared with those free of these conditions (reference category, but more words compared with those with both conditions. There was a significant acceleration in the rate of memory decline in participants aged 50-64 years with both conditions (-0.27, 95% CI, -0.45 to -0.08, per study wave, which was not observed in those with either condition or aged ≥65 years. With respect to executive function (animal naming, participants aged ≥65 years with diabetes or those with elevated depressive symptoms named significantly fewer animals compared with the reference category, while those with both conditions named fewer animals compared with any other category. The rate of executive function decline was significantly greater in participants with both conditions (-0.54, 95% CI, -0.99 to -0.10; and -0.71, 95% CI, -1.16 to -0.27, per study wave, for those aged 50-64 and ≥65 years, respectively, but not in participants with either condition. Diabetes and elevated depressive symptoms are inversely associated with memory and executive function, but, individually, do not accelerate cognitive decline. The co-occurrence of diabetes and elevated depressive symptoms significantly accelerates cognitive decline over time, especially among those aged 50-64 years.

  1. Computational Method for Ice Crystal Trajectories in a Turbofan Compressor

    NARCIS (Netherlands)

    Grift, E.J.; Norde, Ellen; van der Weide, Edwin Theodorus Antonius; Hoeijmakers, Hendrik Willem Marie

    2015-01-01

    In this study the characteristics of ice crystals on their trajectory in a single stage of a turbofan engine compressor are determined. The particle trajectories are calculated with a Lagrangian method employing a classical fourth-order Runge-Kutta time integration scheme. The air flow field is

  2. 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])…

  3. Developmental Trajectories of Girls' and Boys' Delinquency and Associated Problems

    Science.gov (United States)

    Pepler, Debra J.; Jiang, Depeng; Craig, Wendy M.; Connolly, Jennifer

    2010-01-01

    Developmental trajectories in delinquency through adolescence were studied along with family and peer relationship problems. Drawing from eight waves of data over seven years, we conducted trajectory analyses with a sample of 746 students (402 girls; 344 boys). Analyzing girls and boys together, a five-class model emerged: 60% of the adolescents…

  4. Trajectories of metabolic risk factors and biochemical markers prior to the onset of type 2 diabetes : the population-based longitudinal Doetinchem study

    NARCIS (Netherlands)

    Hulsegge, G; Spijkerman, A M W; van der Schouw, Y T; Bakker, Stephan J. L.; Gansevoort, R T; Smit, H A; Verschuren, W M M

    2017-01-01

    BACKGROUND: Risk factors often develop at young age and are maintained over time, but it is not fully understood how risk factors develop over time preceding type 2 diabetes. We examined how levels and trajectories of metabolic risk factors and biochemical markers prior to diagnosis differ between

  5. Making Gender Matter: Knowledge Ecologies, Contested Research Objects, and the Trajectory of Women's and Gender Studies in American Universities, 1970-2010

    Science.gov (United States)

    Wood, Christine Virginia

    2014-01-01

    This dissertation examines the trajectory of research programs on women and gender in American universities between 1970 and 2010. The dissertation melds perspectives in the sociology of science with organizational analyses of the development of academic disciplines. The analysis forwards a new understanding of how local conditions in research…

  6. Indexing the Trajectories of Moving Objects in Symbolic Indoor Space

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Lu, Hua; Yang, Bin

    2009-01-01

    . This scenario calls for the indexing of indoor trajectories. Based on an appropriate notion of indoor trajectory and definitions of pertinent types of queries, the paper proposes two R-tree based structures for indexing object trajectories in symbolic indoor space. The RTR-tree represents a trajectory as a set......Indoor spaces accommodate large populations of individuals. With appropriate indoor positioning, e.g., Bluetooth and RFID, in place, large amounts of trajectory data result that may serve as a foundation for a wide variety of applications, e.g., space planning, way finding, and security...... for each index. An empirical performance study suggests that the two indexes are effective, efficient, and robust. The study also elicits the circumstances under which our proposals perform the best....

  7. Friendship networks and trajectories of adolescent tobacco use.

    Science.gov (United States)

    Pollard, Michael S; Tucker, Joan S; Green, Harold D; Kennedy, David; Go, Myong-Hyun

    2010-07-01

    This article examines how friendship networks in adolescence are linked to tobacco use trajectories through a combination of analytic techniques that traditionally are located in separate literatures: social network analysis and developmental trajectory analysis. Using six years of longitudinal data from the National Longitudinal Study of Adolescent Health, we identify a set of six unique developmental trajectories of smoking (never smokers, steady lows, delayed increasers, early increasers, decreasers, and steady highs). Individuals' locations in their friendship networks were then linked to their trajectory group membership. Adolescents with a greater number of smoking friends were more likely to belong to the higher use trajectories. Beyond this exposure to smoking peers, individuals who at baseline were either members of a smoking group or liaisons to a smoking group were more likely than members of a nonsmoking group to belong to the higher use trajectories. Liaisons to a smoking group were particularly likely to belong to the delayed increaser trajectory group. Trajectory group membership for adolescents who belonged to a nonsmoking group did not significantly differ from those who were isolates or liaisons to a nonsmoking group. The study suggests features of an individual's social network have long-lasting associations with smoking behaviors. 2010 Elsevier Ltd. All rights reserved.

  8. Longitudinal sex differences of externalising and internalising depression symptom trajectories: Implications for assessment of depression in men from an online study.

    Science.gov (United States)

    Rice, Simon M; Fallon, Barry J; Aucote, Helen M; Möller-Leimkühler, AnneMaria; Treeby, Matt S; Amminger, G Paul

    2015-05-01

    Clinical reports indicate that men tend to engage in a range of externalising behaviours in response to negative emotional states. Such externalising behaviours have been theorised to reflect a male sub-type of depression that is inconsistent with current diagnostic criteria, resulting in impeded detection and treatment rates of depressed men. In addressing previous study design limitations, this article presents self-report longitudinal data for the multidimensional Male Depression Risk Scale (MDRS-22) against ratings of diagnostic criteria for major depressive disorder as assessed by the Patient Health Questionnaire-Depression Module (PHQ-9). Longitudinal psychometric properties of the MDRS-22 are reported and symptom trajectories described. A sample of 233 adults (males = 125; 54%) completed measures of externalising and prototypic depression symptoms at Time 1, and again at Time 2 (15 weeks later). Psychometric properties were examined and within-subjects analyses undertaken. The MDRS-22 demonstrated stable internal consistency and test-retest correlations equivalent to those observed for the PHQ-9. Both prototypic and externalising depression symptoms increased with experiences of recent negative life events. Marked gender differences were observed. Males experiencing ≥ 2 stressful negative life events reported significantly higher MDRS-22 scores at both Time 1 and Time 2 relative to comparable females. Findings contribute to the validity of the MDRS-22 as a measure of externalising depression symptoms. Results suggest that while both males and females experience externalising depression symptoms, these symptoms may be particularly elevated for men following experiences of negative life events. Findings suggest that externalising symptoms may be a special feature of depression for men. Given the problematic nature of such externalising symptoms (e.g. excessive substance use, aggression, risk-taking), their clinical assessment appears warranted. © The Author

  9. Pre-event trajectories of mental health and health-related disabilities, and post-event traumatic stress symptoms and health: A 7-wave population-based study.

    Science.gov (United States)

    van der Velden, Peter G; Bosmans, Mark W G; van der Meulen, Erik; Vermunt, Jeroen K

    2016-12-30

    It is unknown to what extent classes of trajectories of pre-event mental health problems (MHP) and health-related disabilities (HRD), predict post-event traumatic stress symptoms (PTSS), MHP and HRD. Aim of the present 7-wave study was to assess the predictive values using a representative sample of adult Dutch (N=4052) participating in three health-surveys in November-December 2009 (T1), 2010 (T2), 2011 (T3). In total, 2988 out of 4052 also participated in trauma-surveys in April(T4), August(T5) and December(T6) 2012 and a fourth health-survey in November-December 2012 (T7). About 10% (N=314) was confronted with potentially traumatic events (PTE) in the 4 months before T4 or T5. Latent class analyses among 4052 respondents identified four classes of pre-event MHP and HRD. Series of multivariate logistic regression analyses with class membership, peri-traumatic stress, type of event, gender, age and education as predictors, showed that classes with high levels of MHP or HRD, were more at risk for high levels of PTSS at baseline and follow-ups at 4 and 8 months, than classes with low levels of MHP or HRD. These classes were very strong predictors for high levels of post-event MHP and HRD: no differences were found between non-affected and affected respondents with different levels of peri-traumatic stress. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. 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)

    Sletner, Line; Jenum, Anne Karen; Yajnik, Chittaranjan S; Mørkrid, Kjersti; Nakstad, Britt; Rognerud-Jensen, Odd Harald; Birkeland, Kåre I; Vangen, Siri

    2017-01-01

    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. 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. 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. 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.

  11. Long-term River Trajectories to Enhance Restoration Efficiency and Sustainability on the Upper Rhine: an Interdisciplinary Study (Rohrschollen Island, France)

    Science.gov (United States)

    Eschbach, D.; Laurent, S.; May, J. H.; Imfeld, G.; Payraudeau, S.; Preusser, F.

    2017-12-01

    While the history of a fluvial hydrosystem can provide essential knowledge on present functioning, historical context remains rarely considered in river restoration. Here we show the relevance of an interdisciplinary historical study for improving restoration within the framework of a European LIFE+ project on the French side of the Upper-Rhine (Rohrschollen Island). Planimetric evolution combined with historical high flow data enabled to reconstruct pre-disturbance hydromorphological functioning and major changes that occurred on the reach. A deposition frequency assessment combining vertical evolution of the Rhine thalweg, chronology of deposits in the floodplain and a hydrological model revealed that the period of vertical incision in the main channel corresponded to high rates of narrowing and lateral channel filling. The analysis of filling processes by Passega diagram and IRLS dating highlight that periods of engineering works were closely related to fine sediment deposition, which present also concomitant heavy metal accumulation. In fact, current fluvial forms, processes and sediment chemistry around the Rohrschollen Island directly reflect the disturbances that occurred during past correction works, and up to today. Our results underscore the advantage of combining functional restoration with detailed knowledge of past-trajectory to: (i) understand the functioning of the hydrosystem prior anthropogenic disturbances, (ii) characterize the human-driven morphodynamic adjustments during the two last centuries, (iii) characterize physio-chemical sediment properties to trace anthropogenic activities and evaluate the potential impact of the restoration on pollutant remobilization, (iv) deduce post-restoration evolution and (v) evaluate efficiency and sustainability of the restoration effects. We anticipate our approach to expand the toolbox of decision-makers and help orientating functional restoration actions in the future.

  12. Prenatal cerebellar growth trajectories and the impact of periconceptional maternal and fetal factors

    NARCIS (Netherlands)

    Koning, I V; Dudink, J; Groenenberg, I A L; Willemsen, S P; Reiss, I K M; Steegers-Theunissen, R P M

    2017-01-01

    STUDY QUESTION: CAN WE assess human prenatal cerebellar growth from the first until the third trimester of pregnancy and create growth trajectories to investigate associations with periconceptional maternal and fetal characteristics? SUMMARY ANSWER: Prenatal growth trajectories of the human

  13. Developmental Links between Trajectories of Physical Violence, Vandalism, Theft, and Alcohol-Drug Use from Childhood to Adolescence

    Science.gov (United States)

    van Lier, Pol A. C.; Vitaro, Frank; Barker, Edward D.; Koot, Hans M.; Tremblay, Richard E.

    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 increased from ten to 14. All trajectories of…

  14. Generic trajectory representation and trajectory following for wheeled robots

    DEFF Research Database (Denmark)

    Kjærgaard, Morten; Andersen, Nils Axel; Ravn, Ole

    2014-01-01

    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...... in a smooth motion, a method to create a safe velocity profile for the robot, and a path following controller....

  15. Clinical and cognitive trajectories in cognitively healthy elderly individuals with suspected non-Alzheimer's disease pathophysiology (SNAP) or Alzheimer's disease pathology: a longitudinal study.

    Science.gov (United States)

    Burnham, Samantha C; Bourgeat, Pierrick; Doré, Vincent; Savage, Greg; Brown, Belinda; Laws, Simon; Maruff, Paul; Salvado, Olivier; Ames, David; Martins, Ralph N; Masters, Colin L; Rowe, Christopher C; Villemagne, Victor L

    2016-09-01

    Brain amyloid β (Aβ) deposition and neurodegeneration have been documented in about 50-60% of cognitively healthy elderly individuals (aged 60 years or older). The long-term cognitive consequences of the presence of Alzheimer's disease pathology and neurodegeneration, and whether they have an independent or synergistic effect on cognition, are unclear. We aimed to characterise the long-term clinical and cognitive trajectories of healthy elderly individuals using a two-marker (Alzheimer's disease pathology and neurodegeneration) imaging construct. Between Nov 3, 2006, and Nov 25, 2014, 573 cognitively healthy individuals in Melbourne and Perth, Australia, (mean age 73·1 years [SD 6·2]; 58% women) were enrolled in the Australian Imaging, Biomarker and Lifestyle (AIBL) study. Alzheimer's disease pathology (A) was determined by measuring Aβ deposition by PET, and neurodegeneration (N) was established by measuring hippocampal volume using MRI. Individuals were categorised as A(-)N(-), A(+)N(-), A(+)N(+), or suspected non-Alzheimer's disease pathophysiology (A(-)N(+), SNAP). Clinical progression, hippocampal volume, standard neuropsychological tests, and domain-specific and global cognitive composite scores were assessed over 6 years of follow-up. Linear mixed effect models and a Cox proportional hazards model of survival were used to evaluate, compare, and contrast the clinical, cognitive, and volumetric trajectories of patients in the four AN categories. 50 (9%) healthy individuals were classified as A(+)N(+), 87 (15%) as A(+)N(-), 310 (54%) as A(-)N(-), and 126 (22%) as SNAP. APOE ε4 was more frequent in participants in the A(+)N(+) (27; 54%) and A(+)N(-) (42; 48%) groups than in the A(-)N(-) (66; 21%) and SNAP groups (23; 18%). The A(+)N(-) and A(+)N(+) groups had significantly faster cognitive decline than the A(-)N(-) group (0·08 SD per year for AIBL-Preclinical AD Cognitive Composite [PACC]; p<0·0001; and 0·25; p<0·0001; respectively). The A (+)N

  16. Low Thrust Trajectory Design for GSFC Missions

    Data.gov (United States)

    National Aeronautics and Space Administration — The Evolutionary Mission Trajectory Generator (EMTG) is a global trajectory optimization tool. EMTG is intended for use in designing interplanetary missions which...

  17. Logarithmic spiral trajectories generated by Solar sails

    Science.gov (United States)

    Bassetto, Marco; Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

    2018-02-01

    Analytic solutions to continuous thrust-propelled trajectories are available in a few cases only. An interesting case is offered by the logarithmic spiral, that is, a trajectory characterized by a constant flight path angle and a fixed thrust vector direction in an orbital reference frame. The logarithmic spiral is important from a practical point of view, because it may be passively maintained by a Solar sail-based spacecraft. The aim of this paper is to provide a systematic study concerning the possibility of inserting a Solar sail-based spacecraft into a heliocentric logarithmic spiral trajectory without using any impulsive maneuver. The required conditions to be met by the sail in terms of attitude angle, propulsive performance, parking orbit characteristics, and initial position are thoroughly investigated. The closed-form variations of the osculating orbital parameters are analyzed, and the obtained analytical results are used for investigating the phasing maneuver of a Solar sail along an elliptic heliocentric orbit. In this mission scenario, the phasing orbit is composed of two symmetric logarithmic spiral trajectories connected with a coasting arc.

  18. Potential Cislunar and Interplanetary Proving Ground Excursion Trajectory Concepts

    Science.gov (United States)

    McGuire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; MacDonald, Mark A.; McElrath, Timothy P.; Landau, Damon F.; Lantoine, Gregory; Hack, Kurt J.; Lopez, Pedro

    2016-01-01

    NASA has been investigating potential translunar excursion concepts to take place in the 2020s that would be used to test and demonstrate long duration life support and other systems needed for eventual Mars missions in the 2030s. These potential trajectory concepts could be conducted in the proving ground, a region of cislunar and near-Earth interplanetary space where international space agencies could cooperate to develop the technologies needed for interplanetary spaceflight. Enabled by high power Solar Electric Propulsion (SEP) technologies, the excursion trajectory concepts studied are grouped into three classes of increasing distance from the Earth and increasing technical difficulty: the first class of excursion trajectory concepts would represent a 90-120 day round trip trajectory with abort to Earth options throughout the entire length, the second class would be a 180-210 day round trip trajectory with periods in which aborts would not be available, and the third would be a 300-400 day round trip trajectory without aborts for most of the length of the trip. This paper provides a top-level summary of the trajectory and mission design of representative example missions of these three classes of excursion trajectory concepts.

  19. Clustering Trajectories by Relevant Parts for Air Traffic Analysis.

    Science.gov (United States)

    Andrienko, Gennady; Andrienko, Natalia; Fuchs, Georg; Garcia, Jose Manuel Cordero

    2018-01-01

    Clustering of trajectories of moving objects by similarity is an important technique in movement analysis. Existing distance functions assess the similarity between trajectories based on properties of the trajectory points or segments. The properties may include the spatial positions, times, and thematic attributes. There may be a need to focus the analysis on certain parts of trajectories, i.e., points and segments that have particular properties. According to the analysis focus, the analyst may need to cluster trajectories by similarity of their relevant parts only. Throughout the analysis process, the focus may change, and different parts of trajectories may become relevant. We propose an analytical workflow in which interactive filtering tools are used to attach relevance flags to elements of trajectories, clustering is done using a distance function that ignores irrelevant elements, and the resulting clusters are summarized for further analysis. We demonstrate how this workflow can be useful for different analysis tasks in three case studies with real data from the domain of air traffic. We propose a suite of generic techniques and visualization guidelines to support movement data analysis by means of relevance-aware trajectory clustering.

  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. Longitudinal impact of interprofessional education on attitudes, skills and career trajectories: a protocol for a quasi-experimental study in New Zealand.

    Science.gov (United States)

    Darlow, Ben; Brown, Melanie; Gallagher, Peter; Gray, Lesley; McKinlay, Eileen; Purdie, Gordon; Wilson, Christine; Pullon, Sue

    2018-01-21

    Interprofessional practice is recognised as an important element of safe and effective healthcare. However, few studies exist that evaluate how preregistration education contributes to interprofessional competencies, and how these competencies develop throughout the early years of a health professional's career. This quasiexperimental study will gather longitudinal data during students' last year of preregistration training and their first 3 years of professional practice to evaluate the ongoing development of interprofessional competencies and the influence that preregistration education including an explicit interprofessional education (IPE) programme may have on these. Participants are students and graduates from the disciplines of dentistry, dietetics, medicine, nursing, occupational therapy, oral health, pharmacy and physiotherapy recruited before their final year of study. A subset of these students attended a 5-week IPE immersion programme during their final year of training. All data will be collected via five written or electronic surveys completed at 12-month intervals. Each survey will contain the Attitudes Towards Health Care Teams Scale and the Team Skills Scale, as well as quantitative and free-text items to explore vocational satisfaction, career trajectories and influences on these. Students who attend the IPE programme will complete additional free-text items to explore the effects of this programme on their careers. Quantitative analysis will compare scores at each time point, adjusted for baseline scores, for graduates who did and did not participate in the IPE programme. Associations between satisfaction data and discipline, professional setting, location and IPE participation will also be examined. Template analysis will explore free-text themes related to influences on career choices including participation in preregistration IPE. This study has received approval from the University of Otago Ethics Committee (D13/019). Results will be

  4. Flight test trajectory control analysis

    Science.gov (United States)

    Walker, R.; Gupta, N.

    1983-01-01

    Recent extensions to optimal control theory applied to meaningful linear models with sufficiently flexible software tools provide powerful techniques for designing flight test trajectory controllers (FTTCs). This report describes the principal steps for systematic development of flight trajectory controllers, which can be summarized as planning, modeling, designing, and validating a trajectory controller. The techniques have been kept as general as possible and should apply to a wide range of problems where quantities must be computed and displayed to a pilot to improve pilot effectiveness and to reduce workload and fatigue. To illustrate the approach, a detailed trajectory guidance law is developed and demonstrated for the F-15 aircraft flying the zoom-and-pushover maneuver.

  5. Long Range Aircraft Trajectory Prediction

    OpenAIRE

    Magister, Tone

    2009-01-01

    The subject of the paper is the improvement of the aircraft future trajectory prediction accuracy for long-range airborne separation assurance. The strategic planning of safe aircraft flights and effective conflict avoidance tactics demand timely and accurate conflict detection based upon future four–dimensional airborne traffic situation prediction which is as accurate as each aircraft flight trajectory prediction. The improved kinematics model of aircraft relative flight considering flight ...

  6. 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

  7. 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 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.

  8. BMI trajectory groups in veterans of the Iraq and Afghanistan wars.

    Science.gov (United States)

    Rosenberger, Patricia H; Ning, Yuming; Brandt, Cynthia; Allore, Heather; Haskell, Sally

    2011-09-01

    The study sought to determine BMI trajectories in Iraq/Afghanistan veterans over 6 years and to examine sociodemographic factors associated with BMI trajectory membership. Our study sample included 16,656 veterans post-deployment and entering the Veteran Healthcare Administration (VHA) healthcare system. We used national VHA administrative sociodemographic data, tracked veteran BMI for 6 years, and used trajectory modeling to identify BMI trajectories and sociodemographic characteristics associated with trajectory membership. Five trajectory groups determined in the full sample were primarily differentiated by their post-deployment initial BMI: "healthy" (14.1%), "overweight" (36.3%), "borderline obese" (27.9%), "obese" (15.7%), and "severely obese" (6.0). Being female, younger, and white were associated with lower initial BMI trajectory group membership (p'seducation and white female Veterans were associated with the lowest initial BMI group (p'sEducation level and racial status are differentially related to BMI trajectory by gender. Published by Elsevier Inc.

  9. Gender differences in trajectories of relational aggression perpetration and victimization from middle to high school.

    Science.gov (United States)

    Orpinas, Pamela; McNicholas, Caroline; Nahapetyan, Lusine

    2015-01-01

    Relational aggression refers to harming others through damaging or manipulating peer relationships. In a cohort of students surveyed annually from middle to high school, this study identified groups of adolescents who followed distinct trajectories of perpetration and of victimization of relational aggression, compared the proportion of boys and girls in each trajectory, and examined the overlap between perpetration and victimization trajectories. The sample consisted of 620 randomly selected sixth graders. Students completed yearly surveys from Grade 6-12. We used group-based trajectory modeling to identify the trajectories. Adolescents followed three developmental trajectories of perpetration and three similar trajectories of victimization: Low (lowest aggression), Moderate, and High Declining (high in middle school, with a steep decline in high school). All trajectories declined from Grade 6-12. The largest groups were the Low perpetration (55%) and Low victimization (48%). Relational aggression trajectories differed by gender: more boys reported perpetration, and more girls reported victimization. For perpetration, slightly more boys than girls were classified in the two trajectories of higher aggression. For victimization, significantly fewer girls than boys were classified in the Low trajectory, and significantly more girls than boys were classified in the Moderate trajectory. There was substantial overlap of the perpetration and victimization trajectories. These findings highlight the importance of implementing programs to reduce relational aggression for boys and for girls. © 2014 Wiley Periodicals, Inc.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Trajectories of BMI change impact glucose and insulin metabolism.

    Science.gov (United States)

    Walsh, E I; Shaw, J; Cherbuin, N

    2018-03-01

    The aim of this study was to examine, in a community setting, whether trajectory of weight change over twelve years is associated with glucose and insulin metabolism at twelve years. Participants were 532 community-living middle-aged and elderly adults from the Personality and Total Health (PATH) Through Life study. They spanned the full weight range (underweight/normal/overweight/obese). Latent class analysis and multivariate generalised linear models were used to investigate the association of Body Mass Index (BMI, kg/m 2 ) trajectory over twelve years with plasma insulin (μlU/ml), plasma glucose (mmol/L), and HOMA2 insulin resistance and beta cell function at follow-up. All models were adjusted for age, gender, hypertension, pre-clinical diabetes status (normal fasting glucose or impaired fasting glucose) and physical activity. Four weight trajectories were extracted; constant normal (mean baseline BMI = 25; follow-up BMI = 25), constant high (mean baseline BMI = 36; follow-up BMI = 37), increase (mean baseline BMI = 26; follow-up BMI = 32) and decrease (mean baseline BMI = 34; follow-up BMI = 28). At any given current BMI, individuals in the constant high and increase trajectories had significantly higher plasma insulin, greater insulin resistance, and higher beta cell function than those in the constant normal trajectory. Individuals in the decrease trajectory did not differ from the constant normal trajectory. Current BMI significantly interacted with preceding BMI trajectory in its association with plasma insulin, insulin resistance, and beta cell function. The trajectory of preceding weight has an independent effect on blood glucose metabolism beyond body weight measured at any given point in time. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier

  16. A teacher's identity trajectory within a context of change

    African Journals Online (AJOL)

    Hennie

    change in South Africa on a teacher's identity trajectory. The data was generated ... Iris was articulate, a strong voice in the school, eager to share her experiences and .... (Perold et al., 2012). Comparative international studies, such as the.

  17. 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…

  18. Kinematic geometry of a line trajectory in spatial motion

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghefari, Reem A. [King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Baky, Rashad A. [University of Assiut, Assiu (Egypt)

    2015-09-15

    This paper derives the equations of line-trajectory in spatial motion by means of the E. Study dual-line coordinates. A special emphasis goes to the second-order motion properties for deriving a new proof of the Disteli formulae. As an application concise explicit expressions of the inflection line congruence are directly obtained. Also, a new metric is developed and used to investigate the geometrical properties and kinematics of line trajectory as well as Disteli axis. Finally, a theoretical expressions of point trajectories with special values of velocity and acceleration, which can be considered as a form Euler-Savary equation, for spherical and planar motions are discussed.

  19. Dissipative quantum trajectories in complex space: Damped harmonic oscillator

    International Nuclear Information System (INIS)

    Chou, Chia-Chun

    2016-01-01

    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.

  20. SPATIO-TEMPORAL PATTERN MINING ON TRAJECTORY DATA USING ARM

    Directory of Open Access Journals (Sweden)

    S. Khoshahval

    2017-09-01

    Full Text Available Preliminary mobile was considered to be a device to make human connections easier. But today the consumption of this device has been evolved to a platform for gaming, web surfing and GPS-enabled application capabilities. Embedding GPS in handheld devices, altered them to significant trajectory data gathering facilities. Raw GPS trajectory data is a series of points which contains hidden information. For revealing hidden information in traces, trajectory data analysis is needed. One of the most beneficial concealed information in trajectory data is user activity patterns. In each pattern, there are multiple stops and moves which identifies users visited places and tasks. This paper proposes an approach to discover user daily activity patterns from GPS trajectories using association rules. Finding user patterns needs extraction of user’s visited places from stops and moves of GPS trajectories. In order to locate stops and moves, we have implemented a place recognition algorithm. After extraction of visited points an advanced association rule mining algorithm, called Apriori was used to extract user activity patterns. This study outlined that there are useful patterns in each trajectory that can be emerged from raw GPS data using association rule mining techniques in order to find out about multiple users’ behaviour in a system and can be utilized in various location-based applications.

  1. Dissipative quantum trajectories in complex space: Damped harmonic oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chia-Chun, E-mail: ccchou@mx.nthu.edu.tw

    2016-10-15

    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.

  2. Spatio-Temporal Pattern Mining on Trajectory Data Using Arm

    Science.gov (United States)

    Khoshahval, S.; Farnaghi, M.; Taleai, M.

    2017-09-01

    Preliminary mobile was considered to be a device to make human connections easier. But today the consumption of this device has been evolved to a platform for gaming, web surfing and GPS-enabled application capabilities. Embedding GPS in handheld devices, altered them to significant trajectory data gathering facilities. Raw GPS trajectory data is a series of points which contains hidden information. For revealing hidden information in traces, trajectory data analysis is needed. One of the most beneficial concealed information in trajectory data is user activity patterns. In each pattern, there are multiple stops and moves which identifies users visited places and tasks. This paper proposes an approach to discover user daily activity patterns from GPS trajectories using association rules. Finding user patterns needs extraction of user's visited places from stops and moves of GPS trajectories. In order to locate stops and moves, we have implemented a place recognition algorithm. After extraction of visited points an advanced association rule mining algorithm, called Apriori was used to extract user activity patterns. This study outlined that there are useful patterns in each trajectory that can be emerged from raw GPS data using association rule mining techniques in order to find out about multiple users' behaviour in a system and can be utilized in various location-based applications.

  3. 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.

  4. Pregnancy Anxiety and Prenatal Cortisol Trajectories

    Science.gov (United States)

    Kane, Heidi S.; Schetter, Christine Dunkel; Glynn, Laura M.; Hobel, Calvin J.; Sandman, Curt A.

    2014-01-01

    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 to 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. PMID:24769094

  5. Life Course Trajectories of Labour Market Participation among Young Adults Who Experienced Severe Alcohol-Related Health Outcomes: A Retrospective Cohort Study.

    Science.gov (United States)

    Paljärvi, Tapio; Martikainen, Pekka; Pensola, Tiina; Leinonen, Taina; Herttua, Kimmo; Mäkelä, Pia

    2015-01-01

    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.

  6. 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.

  7. Origin of chaos in 3-d Bohmian trajectories

    International Nuclear Information System (INIS)

    Tzemos, Athanasios C.; Contopoulos, George; Efthymiopoulos, Christos

    2016-01-01

    We study the 3-d Bohmian trajectories of a quantum system of three harmonic oscillators. We focus on the mechanism responsible for the generation of chaotic trajectories. We demonstrate the existence of a 3-d analogue of the mechanism found in earlier studies of 2-d systems [1,2], based on moving 2-d ‘nodal point–X-point complexes’. In the 3-d case, we observe a foliation of nodal point–X-point complexes, forming a ‘3-d structure of nodal and X-points’. Chaos is generated when the Bohmian trajectories are scattered at one or more close encounters with such a structure. - Highlights: • A mechanism for the emergence of 3-d Bohmian chaos is proposed. • We demonstrate the existence of a 3-d structure of nodal and X-points. • Chaos is generated when the trajectories are scattered by the X-points.

  8. Origin of chaos in 3-d Bohmian trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Tzemos, Athanasios C., E-mail: thanasistzemos@gmail.com; Contopoulos, George, E-mail: gcontop@academyofathens.gr; Efthymiopoulos, Christos, E-mail: cefthim@academyofathens.gr

    2016-11-25

    We study the 3-d Bohmian trajectories of a quantum system of three harmonic oscillators. We focus on the mechanism responsible for the generation of chaotic trajectories. We demonstrate the existence of a 3-d analogue of the mechanism found in earlier studies of 2-d systems [1,2], based on moving 2-d ‘nodal point–X-point complexes’. In the 3-d case, we observe a foliation of nodal point–X-point complexes, forming a ‘3-d structure of nodal and X-points’. Chaos is generated when the Bohmian trajectories are scattered at one or more close encounters with such a structure. - Highlights: • A mechanism for the emergence of 3-d Bohmian chaos is proposed. • We demonstrate the existence of a 3-d structure of nodal and X-points. • Chaos is generated when the trajectories are scattered by the X-points.

  9. What have we learned from ten years of trajectory research in low back pain?

    DEFF Research Database (Denmark)

    Kongsted, Alice; Kent, Peter; Axén, Iben

    2016-01-01

    , a number of subsequent studies have also identified LBP trajectories and it is timely to provide an overview of their findings and discuss how insights into these trajectories may be helpful for improving our understanding of LBP and its clinical management. Discussion: LBP trajectories in adults have been......, and as a tool to support communication with patients. Conclusions: Investigations of trajectories underpin the notion that differentiation between acute and chronic LBP is overly simplistic, and we believe it is time to shift from this paradigm to one that focuses on trajectories over time. We suggest...

  10. Decomposition of gene expression state space trajectories.

    Directory of Open Access Journals (Sweden)

    Jessica C Mar

    2009-12-01

    Full Text Available Representing and analyzing complex networks remains a roadblock to creating dynamic network models of biological processes and pathways. The study of cell fate transitions can reveal much about the transcriptional regulatory programs that underlie these phenotypic changes and give rise to the coordinated patterns in expression changes that we observe. The application of gene expression state space trajectories to capture cell fate transitions at the genome-wide level is one approach currently used in the literature. In this paper, we analyze the gene expression dataset of Huang et al. (2005 which follows the differentiation of promyelocytes into neutrophil-like cells in the presence of inducers dimethyl sulfoxide and all-trans retinoic acid. Huang et al. (2005 build on the work of Kauffman (2004 who raised the attractor hypothesis, stating that cells exist in an expression landscape and their expression trajectories converge towards attractive sites in this landscape. We propose an alternative interpretation that explains this convergent behavior by recognizing that there are two types of processes participating in these cell fate transitions-core processes that include the specific differentiation pathways of promyelocytes to neutrophils, and transient processes that capture those pathways and responses specific to the inducer. Using functional enrichment analyses, specific biological examples and an analysis of the trajectories and their core and transient components we provide a validation of our hypothesis using the Huang et al. (2005 dataset.

  11. 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. 2010 APA, all rights reserved

  12. Classical models for Regge trajectories

    International Nuclear Information System (INIS)

    Biedenharn, L.C.; Van Dam, H.; Marmo, G.; Morandi, G.; Mukunda, N.; Samuel, J.; Sudarshan, E.C.G.

    1987-01-01

    Two classical models for particles with internal structure and which describe Regge trajectories are developed. The remarkable geometric and other properties of the two internal spaces are highlighted. It is shown that the conditions of positive time-like four-velocity and energy momentum for the classical system imply strong and physically reasonable conditions on the Regge mass-spin relationship

  13. 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.

  14. Visiting Vehicle Ground Trajectory Tool

    Science.gov (United States)

    Hamm, Dustin

    2013-01-01

    The International Space Station (ISS) Visiting Vehicle Group needed a targeting tool for vehicles that rendezvous with the ISS. The Visiting Vehicle Ground Trajectory targeting tool provides the ability to perform both realtime and planning operations for the Visiting Vehicle Group. This tool provides a highly reconfigurable base, which allows the Visiting Vehicle Group to perform their work. The application is composed of a telemetry processing function, a relative motion function, a targeting function, a vector view, and 2D/3D world map type graphics. The software tool provides the ability to plan a rendezvous trajectory for vehicles that visit the ISS. It models these relative trajectories using planned and realtime data from the vehicle. The tool monitors ongoing rendezvous trajectory relative motion, and ensures visiting vehicles stay within agreed corridors. The software provides the ability to update or re-plan a rendezvous to support contingency operations. Adding new parameters and incorporating them into the system was previously not available on-the-fly. If an unanticipated capability wasn't discovered until the vehicle was flying, there was no way to update things.

  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

    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......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...... 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. Shaping low-thrust trajectories with thrust-handling feature

    Science.gov (United States)

    Taheri, Ehsan; Kolmanovsky, Ilya; Atkins, Ella

    2018-02-01

    Shape-based methods are becoming popular in low-thrust trajectory optimization due to their fast computation speeds. In existing shape-based methods constraints are treated at the acceleration level but not at the thrust level. These two constraint types are not equivalent since spacecraft mass decreases over time as fuel is expended. This paper develops a shape-based method based on a Fourier series approximation that is capable of representing trajectories defined in spherical coordinates and that enforces thrust constraints. An objective function can be incorporated to minimize overall mission cost, i.e., achieve minimum ΔV . A representative mission from Earth to Mars is studied. The proposed Fourier series technique is demonstrated capable of generating feasible and near-optimal trajectories. These attributes can facilitate future low-thrust mission designs where different trajectory alternatives must be rapidly constructed and evaluated.

  17. Partitioning of the nonfixed excess energy and the reverse critical energy in CH2OH + --> CHO + +H2: A classical trajectory study

    Science.gov (United States)

    Lee, Tae Geol; Kim, Myung Soo; Park, Seung C.

    1996-04-01

    Dynamics of the four-centered elimination reaction CH2OH+→CHO++H2 has been investigated over the internal energy range 4.6-5.9 eV using the classical trajectory method. A realistic semiempirical potential reported previously [J. Chem. Phys. (in press, 1996)] has been used for the calculation. It has been found that the disposal of the nonfixed excess energy at the transition state and of the reverse critical energy can be considered independently as manifest in the sum rule analysis. The former is determined statistically while the latter dynamically. Based on the above idea, a method to determine the kinetic energy release distribution originating only from the reverse critical energy has been developed.

  18. 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

  19. Dynamic trajectory-based couch motion for improvement of radiation therapy trajectories in cranial SRT

    International Nuclear Information System (INIS)

    MacDonald, R. Lee; Thomas, Christopher G.

    2015-01-01

    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

  20. Trajectories of Leisure Activity and Disability in Older Adults Over 11 Years in Taiwan.

    Science.gov (United States)

    Yu, Hsiao-Wei; Chiang, Tung-Liang; Chen, Duan-Rung; Tu, Yu-Kang; Chen, Ya-Mei

    2018-06-01

    We aimed to identify leisure activity (LA) trajectories and examined the association among baseline characteristics, LA trajectories, and the later disability among older Taiwanese adults. Data were from the Taiwan Longitudinal Study on Aging Survey for the years 1996-2007 ( N = 3,186). LA trajectories were identified by using latent class growth curve modeling. Regression analyses were applied to predict the relationships among baseline characteristics, LA trajectories, and disability. Four LA trajectories-consistent high, consistent low, increasing, and decreasing-were identified. Lower depressive symptom was related to consistently active in LAs. Younger age and fewer comorbidities were related to develop an increasing LA trajectory. Participants in the consistent-high or increasing LA trajectories were more likely to be functionally independent, but those in the decreasing LA subgroup were more at risk of developing disability. The findings suggested that long-term changes in LA over time have benefits on physical health in older population.

  1. 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.

  2. User Oriented Trajectory Search for Trip Recommendation

    KAUST Repository

    Ding, Ruogu

    2012-01-01

    Trajectory sharing and searching have received significant attention in recent years. In this thesis, we propose and investigate the methods to find and recommend the best trajectory to the traveler, and mainly focus on a novel technique named User

  3. Aircraft 4D trajectories planning under uncertainties

    OpenAIRE

    Chaimatanan , Supatcha; Delahaye , Daniel; Mongeau , Marcel

    2015-01-01

    International audience; To sustain the rapidly increasing air traffic demand, the future air traffic management system will rely on a concept, called Trajectory-Based Operations (TBO), that will require aircraft to follow an assigned 4D trajectory (time-constrained trajectory) with high precision. TBO involves separating aircraft via strategic (long-term) trajectory deconfliction rather than the currently-practicing tactical (short-term) conflict resolution. In this context, this paper presen...

  4. Trajectories of positive, negative and general psychopathology symptoms in first episode psychosis and their relationship with functioning over a 2-year follow-up period.

    Science.gov (United States)

    Abdin, Edimansyah; Chong, Siow Ann; Vaingankar, Janhavi Ajit; Peh, Chao Xu; Poon, Lye Yin; Rao, Sujatha; Verma, Swapna; Subramaniam, Mythily

    2017-01-01

    Few studies have examined the trajectories of symptom severity in first episode psychosis (FEP) and their impact on functioning. This study aimed to identify discrete trajectories of positive, negative and general psychopathological symptoms and functioning, determine predictors of the identified symptom trajectories and subsequently investigate the relationship between symptom and functioning trajectories over the 2-year follow-up period. Data were extracted from the Singapore Early Psychosis Intervention Programme clinical database. Trajectories of the Positive and Negative Syndrome Scale and Global Assessment of Functioning (GAF) scale over the two-year follow up were modelled using latent class growth curve modelling. Two distinct trajectories (early response and stable trajectory and delayed response trajectory) for positive symptoms, four distinct trajectories (early response and stable trajectory, early response and relapse trajectory, slower response and no response trajectory and delayed response trajectory) for negative and general psychopathology symptoms and three distinct trajectories for functioning (high functioning trajectory, moderately stable functioning trajectory and deterioration in functioning trajectory) were identified in our sample. Compared to individuals in the early response and stable trajectory, those in the delayed response trajectory for positive and negative symptoms, early response and relapse for negative and general psychopathology symptoms and slower response and no response trajectories for general psychopathology symptoms were significantly associated with higher odds of having deterioration in functioning over time. Poor symptom trajectories were also significantly predicted by younger age, male gender, unemployed and economically inactive status, lower education, longer duration of untreated psychosis and diagnosis of schizophrenia spectrum and delusional disorders. The results confirm that the symptoms trajectories among

  5. Trajectories of positive, negative and general psychopathology symptoms in first episode psychosis and their relationship with functioning over a 2-year follow-up period.

    Directory of Open Access Journals (Sweden)

    Edimansyah Abdin

    Full Text Available Few studies have examined the trajectories of symptom severity in first episode psychosis (FEP and their impact on functioning. This study aimed to identify discrete trajectories of positive, negative and general psychopathological symptoms and functioning, determine predictors of the identified symptom trajectories and subsequently investigate the relationship between symptom and functioning trajectories over the 2-year follow-up period.Data were extracted from the Singapore Early Psychosis Intervention Programme clinical database. Trajectories of the Positive and Negative Syndrome Scale and Global Assessment of Functioning (GAF scale over the two-year follow up were modelled using latent class growth curve modelling.Two distinct trajectories (early response and stable trajectory and delayed response trajectory for positive symptoms, four distinct trajectories (early response and stable trajectory, early response and relapse trajectory, slower response and no response trajectory and delayed response trajectory for negative and general psychopathology symptoms and three distinct trajectories for functioning (high functioning trajectory, moderately stable functioning trajectory and deterioration in functioning trajectory were identified in our sample. Compared to individuals in the early response and stable trajectory, those in the delayed response trajectory for positive and negative symptoms, early response and relapse for negative and general psychopathology symptoms and slower response and no response trajectories for general psychopathology symptoms were significantly associated with higher odds of having deterioration in functioning over time. Poor symptom trajectories were also significantly predicted by younger age, male gender, unemployed and economically inactive status, lower education, longer duration of untreated psychosis and diagnosis of schizophrenia spectrum and delusional disorders.The results confirm that the symptoms

  6. Sustaining trajectory flexibility for air traffic complexity alleviation

    Science.gov (United States)

    Hasan, Saam N.; Rossiter, J. A.

    2012-11-01

    Despite the fact that several Air Traffic Management (ATM) complexity metrics have been proposed in the past few years, very few of these studies incorporate a control independent intrinsic approach to the problem with the aim of sustaining trajectory flexibility. This paper proposes the introduction of novel decision making metrics for sustaining user trajectory flexibility. The hypothesis is, if all aircraft apply a flexibility preservation function, complexity may reduce automatically. The functions proposed combine concepts of adaptability, robustness and intrinsic traffic complexity metrics based on Lyapunov exponents. Adaptability is defined as a measure of the ability of the aircraft to change its planned trajectory in response to the occurrence of a disturbance that renders the current planned trajectory infeasible. The Robustness metric is defined as the ability of the aircraft to keep its planned trajectory unchanged in response to the occurrence of disturbances. An Intrinsic complexity measure is used to evaluate the level of disorder with regards to the aircraft trajectory; disorder is defined in this context as the level of consistency in the flow patterns of aircraft and their proximity. A point mass model for multiple aircraft(s) is used to extract the trajectories and computing a form of characterisation of sensitivity and interdependencies of a set of aircraft trajectories. Lyapunov exponents are used to compute this measure. The main contribution of this paper will be to test the hypothesis by combining the complexity metrics described above. Different operational scenarios are simulated using a airspace environment developed in MATLAB which shows how well the traffic is structured by varying the metrics defined. The simulation shows the efficacy of the metrics to alleviate complexity in a heavily congested airspace.

  7. Understanding interference experiments with polarized light through photon trajectories

    International Nuclear Information System (INIS)

    Sanz, A.S.; Davidovic, M.; Bozic, M.; Miret-Artes, S.

    2010-01-01

    Bohmian mechanics allows to visualize and understand the quantum-mechanical behavior of massive particles in terms of trajectories. As shown by Bialynicki-Birula, Electromagnetism also admits a hydrodynamical formulation when the existence of a wave function for photons (properly defined) is assumed. This formulation thus provides an alternative interpretation of optical phenomena in terms of photon trajectories, whose flow yields a pictorial view of the evolution of the electromagnetic energy density in configuration space. This trajectory-based theoretical framework is considered here to study and analyze the outcome from Young-type diffraction experiments within the context of the Arago-Fresnel laws. More specifically, photon trajectories in the region behind the two slits are obtained in the case where the slits are illuminated by a polarized monochromatic plane wave. Expressions to determine electromagnetic energy flow lines and photon trajectories within this scenario are provided, as well as a procedure to compute them in the particular case of gratings totally transparent inside the slits and completely absorbing outside them. As is shown, the electromagnetic energy flow lines obtained allow to monitor at each point of space the behavior of the electromagnetic energy flow and, therefore, to evaluate the effects caused on it by the presence (right behind each slit) of polarizers with the same or different polarization axes. This leads to a trajectory-based picture of the Arago-Fresnel laws for the interference of polarized light.

  8. Trajectories of women's abortion-related care: A conceptual framework.

    Science.gov (United States)

    Coast, Ernestina; Norris, Alison H; Moore, Ann M; Freeman, Emily

    2018-03-01

    We present a new conceptual framework for studying trajectories to obtaining abortion-related care. It assembles for the first time all of the known factors influencing a trajectory and encourages readers to consider the ways these macro- and micro-level factors operate in multiple and sometimes conflicting ways. Based on presentation to and feedback from abortion experts (researchers, providers, funders, policymakers and advisors, advocates) (n = 325) between 03/06/2014 and 22/08/2015, and a systematic mapping of peer-reviewed literature (n = 424) published between 01/01/2011 and 30/10/2017, our framework synthesises the factors shaping abortion trajectories, grouped into three domains: abortion-specific experiences, individual contexts, and (inter)national and sub-national contexts. Our framework includes time-dependent processes involved in an individual trajectory, starting with timing of pregnancy awareness. This framework can be used to guide testable hypotheses about enabling and inhibiting influences on care-seeking behaviour and consideration about how abortion trajectories might be influenced by policy or practice. Research based on understanding of trajectories has the potential to improve women's experiences and outcomes of abortion-related care. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  9. 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...

  10. An ab initio chemical reaction model for the direct simulation Monte Carlo study of non-equilibrium nitrogen flows.

    Science.gov (United States)

    Mankodi, T K; Bhandarkar, U V; Puranik, B P

    2017-08-28

    A new ab initio based chemical model for a Direct Simulation Monte Carlo (DSMC) study suitable for simulating rarefied flows with a high degree of non-equilibrium is presented. To this end, Collision Induced Dissociation (CID) cross sections for N 2 +N 2 →N 2 +2N are calculated and published using a global complete active space self-consistent field-complete active space second order perturbation theory N 4 potential energy surface and quasi-classical trajectory algorithm for high energy collisions (up to 30 eV). CID cross sections are calculated for only a selected set of ro-vibrational combinations of the two nitrogen molecules, and a fitting scheme based on spectroscopic weights is presented to interpolate the CID cross section for all possible ro-vibrational combinations. The new chemical model is validated by calculating equilibrium reaction rate coefficients that can be compared well with existing shock tube and computational results. High-enthalpy hypersonic nitrogen flows around a cylinder in the transition flow regime are simulated using DSMC to compare the predictions of the current ab initio based chemical model with the prevailing phenomenological model (the total collision energy model). The differences in the predictions are discussed.

  11. Ion trajectories quadrupole mass filters

    International Nuclear Information System (INIS)

    Ursu, D.; Lupsa, N.; Muntean, F.

    1994-01-01

    The present paper aims at bringing some contributions to the understanding of ion motion in quadrupole mass filters. The theoretical treatment of quadrupole mass filter is intended to be a concise derivation of the important physical relationships using Mathieu functions. A simple iterative method of numerical computation has been used to simulate ion trajectories in an ideal quadrupole field. Finally, some examples of calculation are presented with the aid of computer graphics. (Author) 14 Figs., 1 Tab., 20 Refs

  12. Interference, reduced action, and trajectories

    OpenAIRE

    Floyd, Edward 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 dichroma...

  13. Identification of digitized particle trajectories

    CERN Document Server

    Grote, H; Lassalle, J C; Zanella, P

    1973-01-01

    High-energy Physics Laboratories make increasing use of particle detectors which directly produce digital measurements of trajectories at very high rates. Data collected in vast amounts during experiments are then analysed by computer programs whose first task is the recognition of tracks and reconstruction of the interesting events. This paper discusses the applicability of various Pattern Recognition approaches. Examples are given of the problems and the practical achievements in this field.

  14. Trajectories of depressive symptoms over two years postpartum among overweight or obese women

    Science.gov (United States)

    Lee, Chien-Ti; Stroo, Marissa; Fuemmeler, Bernard; Malhotra, Rahul; Østbye, Truls

    2014-01-01

    Background Although depressive symptoms are common postpartum, few studies have followed women beyond 12 months postpartum to investigate changes in the number and severity of these symptoms over time, especially in overweight and obese women. Using two complementary analytical methods, this study aims to identify trajectories of depressive symptoms over two years postpartum among overweight or obese mothers, and assess the demographic, socio-economic , and health covariates for these trajectories. Methods Using longitudinal data from two behavioral intervention studies (KAN-DO and AMP; N = 844), we used latent growth modeling to identify the overall trajectory of depressive symptoms and how it was related to key covariates. Next, we used latent class growth analysis to assess the heterogeneity in the depressive symptom trajectories over time, and thereby, identify subgroups of women with distinct trajectories. Findings The overall trajectory of depressive symptoms over two years postpartum was relatively stable in our sample. However, the presence of three distinct latent class trajectories [stable-low (82.5%), decreasing symptoms (7.3%) and increasing symptoms (10.2%)], identified based on trajectory shape and mean depressive symptom score, supported heterogeneity in depressive symptom trajectories over time. Lower maternal education was related to a higher symptom score, and poorer subjective health status at baseline predicted inclusion in the increasing symptoms trajectory. Conclusions In some overweight or obese mothers postpartum depressive symptoms do not resolve quickly. Practitioners should be aware of this phenomenon and continue to screen for depression for longer periods of time postpartum. PMID:25213748

  15. Vibrational deactivation on chemically reactive potential surfaces: An exact quantum study of a low barrier collinear model of H + FH, D + FD, H + FD and D + FH

    International Nuclear Information System (INIS)

    Schatz, G.C.; Kuppermann, A.

    1980-01-01

    We study vibrational deactivation processes on chemically reactive potential energy surfaces by examining accurate quantum mechanical transition probabilities and rate constants for the collinear H + FH(v), D + FD(v), H + FD(v), and D + FH(v) reactions. A low barrier (1.7 kcal/mole) potential surface is used in these calculations, and we find that for all four reactions, the reactive inelastic rate constants are larger than the nonreactive ones for the same initial and final vibrational states. However, the ratios of these reactive and nonreactive rate constants depend strongly on the vibrational quantum number v and the isotopic composition of the reagents. Nonreactive and reactive transition probabilities for multiquantum jump transitions are generally comparable to those for single quantum transitions. This vibrationally nonadiabatic behavior is a direct consequence of the severe distortion of the diatomic that occurs in a collision on a low barrier reactive surface, and can make chemically reactive atoms like H or D more efficient deactivators of HF or DF than nonreactive collision partners. Many conclusions are in at least qualitative agreement with those of Wilkin's three dimensional quasiclassical trajectory study on the same systems using a similar surface. We also present results for H + HF(v) collisions which show that for a higher barrier potential surface (33 rather than 1.7 kcal/mole), the deactivation process becomes similar in character to that for nonreactive partners, with v→v-1 processes dominating

  16. 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.

  17. Discovery of convoys in trajectory databases

    DEFF Research Database (Denmark)

    Jeung, Hoyoung; Yiu, Man Lung; Zhou, Xiaofang

    2008-01-01

    a group of objects that have traveled together for some time. More specifically, this paper formalizes the concept of a convoy query using density-based notions, in order to capture groups of arbitrary extents and shapes. Convoy discovery is relevant for real-life applications in throughput planning...... convoys are further processed to obtain the actual convoys. Our comprehensive empirical study offers insight into the properties of the paper's proposals and demonstrates that the proposals are effective and efficient on real-world trajectory data....

  18. Trajectories of Sensation Seeking Among Puerto Rican Children and Youth.

    Science.gov (United States)

    Martins, Silvia S; Wall, Melanie M; Eisenberg, Ruth; Blanco, Carlos; Santaella, Julian; Ramos-Olazagasti, Maria; Canino, Glorisa; Bird, Hector R; Brown, Qiana; Duarte, Cristiane S

    2015-12-01

    To document the natural course of sensation seeking from childhood to adolescence, characterize distinct sensation seeking trajectories, and examine how these trajectories vary according to selected predictors. Data were obtained from the Boricua Youth Study, a longitudinal study of 2,491 children and adolescents of Puerto Rican background (3 assessments from 2000 to 2004). First, age-specific sensation seeking levels were characterized, and then age-adjusted residuals were analyzed using growth mixture models. On average, sensation seeking was stable in childhood (ages 5-10 years) and increased during adolescence (ages 11-17 years). Mean scores of sensation seeking were higher in the South Bronx versus Puerto Rico and among males versus females. Four classes of sensation seeking trajectories were observed: most study participants had age-expected sensation seeking trajectories following the average for their age ("normative," 43.8%); others (37.2%) remained consistently lower than the expected average for their age ("low" sensation seeking); some (12.0%) had an "accelerated" sensation seeking trajectory, increasing at a faster rate than expected; and a minority (7.0%) had a decreasing sensation seeking trajectory that started high but decreased, reaching scores slightly higher than the age-average sensation seeking scores ("stabilizers"). Site (South Bronx versus Puerto Rico) and gender were predictors of membership in a specific class of sensation seeking trajectory. It is important to take a developmental approach when examining sensation seeking and to consider gender and the social environment when trying to understand how sensation seeking evolves during childhood and adolescence. Copyright © 2015 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  19. Predictors of Latent Trajectory Classes of Dating Violence Victimization

    Science.gov (United States)

    Brooks-Russell, Ashley; Foshee, Vangie; Ennett, Susan

    2014-01-01

    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 used to identify trajectory classes of physical dating violence victimization separately for girls and boys. Logistic and multinomial logistic regressions were used to identify situational and target vulnerability factors associated with the trajectory classes. For girls, three trajectory classes were identified: a low/non-involved class; a moderate class where victimization increased slightly until the 10th grade and then decreased through the 12th grade; and a high class where victimization started at a higher level in the 8th grade, increased substantially until the 10th grade, and then decreased until the 12th grade. For males, two classes were identified: a low/non-involved class, and a victimized class where victimization increased slightly until the 9th grade, decreased until the 11th grade, and then increased again through the 12th grade. In bivariate analyses, almost all of the situational and target vulnerability risk factors distinguished the victimization classes from the non-involved classes. However, when all risk factors and control variables were in the model, alcohol use (a situational vulnerability) was the only factor that distinguished membership in the moderate trajectory class from the non-involved class for girls; anxiety and being victimized by peers (target vulnerability factors) were the factors that distinguished the high from the non-involved classes for the girls; and victimization by peers was the only factor distinguishing the victimized from the non-involved class for boys. These findings contribute to our understanding of the heterogeneity in physical dating violence victimization during

  20. BMI Trajectories from Birth to Young Adulthood.

    Science.gov (United States)

    McGinty, Shannon M; Osganian, Stavroula K; Feldman, Henry A; Milliren, Carly E; Field, Alison E; Richmond, Tracy K

    2018-04-19

    This study aimed to compare BMI trajectories from childhood to early adulthood in those with overweight and/or obesity versus severe obesity. Longitudinal BMI values (2,542 measurements) were calculated from measured heights and weights for 103 children, adolescents, or young adults with overweight, obesity, or severe obesity. Segmented regression with splines was used to model BMI trajectories. Sixty-nine participants were classified as ever having severe obesity versus 34 who never had severe obesity. Trajectories and slopes did not differ by sex or race/ethnicity. Compared with those who never had severe obesity, BMI was higher in the group with severe obesity at all ages, and BMI slope was higher for those with severe obesity at age 14 (P = 0.002), with peak slope occurring later (18 years vs. 16 years) and higher (4.5 ± 0.5 kg/m 2 /y vs. 2.9 ± 0.5 kg/m 2 /y; P BMI fell below zero by the mid-20s (-0.3 ± 0.6 kg/m 2 /y); in those with severe obesity, BMI slope never reached zero (0.9 ± 0.5 kg/m 2 /y). Youth with severe obesity, compared with their peers without, started with higher BMIs, had more rapid rates of BMI increase beginning at age 14, as well as a higher peak and longer period of increase, and never achieved weight stabilization. © 2018 The Obesity Society.

  1. Trajectories of disposable income among people of working ages diagnosed with multiple sclerosis: a nationwide register-based cohort study in Sweden 7 years before to 4 years after diagnosis with a population-based reference group.

    Science.gov (United States)

    Murley, Chantelle; Mogard, Olof; Wiberg, Michael; Alexanderson, Kristina; Karampampa, Korinna; Friberg, Emilie; Tinghög, Petter

    2018-05-09

    To describe how disposable income (DI) and three main components changed, and analyse whether DI development differed from working-aged people with multiple sclerosis (MS) to a reference group from 7 years before to 4 years after diagnosis in Sweden. Population-based cohort study, 12-year follow-up (7 years before to 4 years after diagnosis). Swedish working-age population with microdata linked from two nationwide registers. Residents diagnosed with MS in 2009 aged 25-59 years (n=785), and references without MS (n=7847) randomly selected with stratified matching (sex, age, education and country of birth). DI was defined as the annual after tax sum of incomes (earnings and benefits) to measure individual economic welfare. Three main components of DI were analysed as annual sums: earnings, sickness absence benefits and disability pension benefits. We found no differences in mean annual DI between people with and without MS by independent t-tests (p values between 0.15 and 0.96). Differences were found for all studied components of DI from diagnosis year by independent t-tests, for example, in the final study year (2013): earnings (-64 867 Swedish Krona (SEK); 95% CI-79 203 to -50 528); sickness absence benefits (13 330 SEK; 95% CI 10 042 to 16 500); and disability pension benefits (21 360 SEK; 95% CI 17 380 to 25 350). A generalised estimating equation evaluated DI trajectory development between people with and without MS to find both trajectories developed in parallel, both before (-4039 SEK; 95% CI -10 536 to 2458) and after (-781 SEK; 95% CI -6988 to 5360) diagnosis. The key finding of parallel DI trajectory development between working-aged MS and references suggests minimal economic impact within the first 4 years of diagnosis. The Swedish welfare system was responsive to the observed reductions in earnings around MS diagnosis through balancing DI with morbidity-related benefits. Future decreases in economic welfare may be experienced as the

  2. Computational Approaches to Simulation and Optimization of Global Aircraft Trajectories

    Science.gov (United States)

    Ng, Hok Kwan; Sridhar, Banavar

    2016-01-01

    This study examines three possible approaches to improving the speed in generating wind-optimal routes for air traffic at the national or global level. They are: (a) using the resources of a supercomputer, (b) running the computations on multiple commercially available computers and (c) implementing those same algorithms into NASAs Future ATM Concepts Evaluation Tool (FACET) and compares those to a standard implementation run on a single CPU. Wind-optimal aircraft trajectories are computed using global air traffic schedules. The run time and wait time on the supercomputer for trajectory optimization using various numbers of CPUs ranging from 80 to 10,240 units are compared with the total computational time for running the same computation on a single desktop computer and on multiple commercially available computers for potential computational enhancement through parallel processing on the computer clusters. This study also re-implements the trajectory optimization algorithm for further reduction of computational time through algorithm modifications and integrates that with FACET to facilitate the use of the new features which calculate time-optimal routes between worldwide airport pairs in a wind field for use with existing FACET applications. The implementations of trajectory optimization algorithms use MATLAB, Python, and Java programming languages. The performance evaluations are done by comparing their computational efficiencies and based on the potential application of optimized trajectories. The paper shows that in the absence of special privileges on a supercomputer, a cluster of commercially available computers provides a feasible approach for national and global air traffic system studies.

  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. Trajectory Design Considerations for Exploration Mission 1

    Science.gov (United States)

    Dawn, Timothy F.; Gutkowski, Jeffrey P.; Batcha, Amelia L.; Williams, Jacob; Pedrotty, Samuel M.

    2018-01-01

    to meet this request. Also, subsystems request feasibility of alternate or contingency mission designs, such as adding an Orion main engine checkout burn or Orion completing all of its burns using only its auxiliary thrusters. This paper examines and presents the evolving trade studies that incorporate subsystem feedback and demonstrate the feasibility of these constrained mission trajectory designs and contingencies.

  5. Optimal trajectories of aircraft and spacecraft

    Science.gov (United States)

    Miele, A.

    1990-01-01

    Work done on algorithms for the numerical solutions of optimal control problems and their application to the computation of optimal flight trajectories of aircraft and spacecraft is summarized. General considerations on calculus of variations, optimal control, numerical algorithms, and applications of these algorithms to real-world problems are presented. The sequential gradient-restoration algorithm (SGRA) is examined for the numerical solution of optimal control problems of the Bolza type. Both the primal formulation and the dual formulation are discussed. Aircraft trajectories, in particular, the application of the dual sequential gradient-restoration algorithm (DSGRA) to the determination of optimal flight trajectories in the presence of windshear are described. Both take-off trajectories and abort landing trajectories are discussed. Take-off trajectories are optimized by minimizing the peak deviation of the absolute path inclination from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. The survival capability of an aircraft in a severe windshear is discussed, and the optimal trajectories are found to be superior to both constant pitch trajectories and maximum angle of attack trajectories. Spacecraft trajectories, in particular, the application of the primal sequential gradient-restoration algorithm (PSGRA) to the determination of optimal flight trajectories for aeroassisted orbital transfer are examined. Both the coplanar case and the noncoplanar case are discussed within the frame of three problems: minimization of the total characteristic velocity; minimization of the time integral of the square of the path inclination; and minimization of the peak heating rate. The solution of the second problem is called nearly-grazing solution, and its merits are pointed out as a useful

  6. Complexity in Individual Trajectories toward Online Extremism

    Directory of Open Access Journals (Sweden)

    Z. Cao

    2018-01-01

    Full Text Available Society faces a fundamental global problem of understanding which individuals are currently developing strong support for some extremist entity such as ISIS (Islamic State, even if they never end up doing anything in the real world. The importance of online connectivity in developing intent has been confirmed by recent case studies of already convicted terrorists. Here we use ideas from Complexity to identify dynamical patterns in the online trajectories that individuals take toward developing a high level of extremist support, specifically, for ISIS. Strong memory effects emerge among individuals whose transition is fastest and hence may become “out of the blue” threats in the real world. A generalization of diagrammatic expansion theory helps quantify these characteristics, including the impact of changes in geographical location, and can facilitate prediction of future risks. By quantifying the trajectories that individuals follow on their journey toward expressing high levels of pro-ISIS support—irrespective of whether they then carry out a real-world attack or not—our findings can help move safety debates beyond reliance on static watch-list identifiers such as ethnic background or immigration status and/or postfact interviews with already convicted individuals. Given the broad commonality of social media platforms, our results likely apply quite generally; for example, even on Telegram where (like Twitter there is no built-in group feature as in our study, individuals tend to collectively build and pass through the so-called super-group accounts.

  7. 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, pdepressive 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.

  8. Sex differences in normal age trajectories of functional brain networks.

    Science.gov (United States)

    Scheinost, Dustin; Finn, Emily S; Tokoglu, Fuyuze; Shen, Xilin; Papademetris, Xenophon; Hampson, Michelle; Constable, R Todd

    2015-04-01

    Resting-state functional magnetic resonance image (rs-fMRI) is increasingly used to study functional brain networks. Nevertheless, variability in these networks due to factors such as sex and aging is not fully understood. This study explored sex differences in normal age trajectories of resting-state networks (RSNs) using a novel voxel-wise measure of functional connectivity, the intrinsic connectivity distribution (ICD). Males and females showed differential patterns of changing connectivity in large-scale RSNs during normal aging from early adulthood to late middle-age. In some networks, such as the default-mode network, males and females both showed decreases in connectivity with age, albeit at different rates. In other networks, such as the fronto-parietal network, males and females showed divergent connectivity trajectories with age. Main effects of sex and age were found in many of the same regions showing sex-related differences in aging. Finally, these sex differences in aging trajectories were robust to choice of preprocessing strategy, such as global signal regression. Our findings resolve some discrepancies in the literature, especially with respect to the trajectory of connectivity in the default mode, which can be explained by our observed interactions between sex and aging. Overall, results indicate that RSNs show different aging trajectories for males and females. Characterizing effects of sex and age on RSNs are critical first steps in understanding the functional organization of the human brain. © 2014 Wiley Periodicals, Inc.

  9. Ray trajectories for Alcubierre spacetime

    International Nuclear Information System (INIS)

    Anderson, Tom H; Mackay, Tom G; 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 continuous functions of the spatial coordinates. Accordingly, the Tamm medium is amenable to physical realization as a micro- or 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 focusing lens, most notably at high speeds

  10. Mothers' Depression and Educational Attainment and Their Children's Academic Trajectories

    Science.gov (United States)

    Augustine, Jennifer March; Crosnoe, Robert

    2010-01-01

    In this study, we take a dynamic approach to studying the connections among mothers' education, their depression, and their children's academic trajectories during elementary school. Applying latent growth curve modeling to longitudinal data from the National Institute of Child Health and Human Development's Study of Early Child Care and Youth…

  11. climatology of air mass trajectories and aerosol optical thickness ...

    African Journals Online (AJOL)

    George

    We present in this paper a climatological study of back trajectories of air masses ... obtained by inversion of photometric measurements of AERONET network. ... the arid Sahel region adjacent in the north to the Sahara ... the city a strategic position in the study of the .... atmospheric emergencies, diagnostic case studies and.

  12. 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.

  13. 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

  14. Mean motion and trajectories of heavy particles falling through a boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Stout, J.E.; Arya, S.P. [North Carolina State Univ., Raleigh, NC (United States)

    1994-12-31

    As particles fall through a turbulent boundary layer they experience a rather complex and unique time series of aerodynamic forces and, thus, each individual particle follows a rather complex and unique trajectory to the surface. For sufficiently large and heavy particles, the turbulence induced particle motion can be thought of as a small perturbation superimposed on the mean trajectory. By ignoring the turbulent contribution to particle motion it is possible to calculate the trajectory of a particle due to the mean flow alone. The mean trajectory provides an estimate of the ensemble-averaged path of a set of particles released from a given point in the atmosphere. The effect of turbulence on individual particle trajectories, the distribution of particle displacements from the mean trajectory, and their deposition patterns on the surface will be investigated in a separate study, using a random walk model.

  15. The illness trajectory experienced by patients having spine fusion surgery

    DEFF Research Database (Denmark)

    Damsgaard, Janne Brammer; Bastrup, Lene; Norlyk, Annelise

    The illness trajectory of spine fusion patients. A feeling of being (in)visible Background Research shows that being a back patient is associated with great personal cost, and that back patients who undergo so-called spine fusion often experience particularly long and uncoordinated trajectories....... The patients describe a feeling of being mistrusted and thrown around in the system. It is the aim of this study to examine how spine fusion patients experience their illness trajectory and hospitalisation. Methods The study is based on qualitative interviews, and the data analysis is inspired by the French...... system and healthcare professionals are often dismissed as irrelevant. It is also evident that spine fusion patients are denied the opportunity to verbalise what it feels like to, for example, be ”a person in constant pain” or someone who ”holds back” to avoid being an inconvenience. These feelings...

  16. [Mothers of children with autistic disorder: perceptions and trajectories].

    Science.gov (United States)

    Ebert, Michele; Lorenzini, Elisiane; da Silva, Eveline Franco

    2015-03-01

    Childhood autism is characterized by severe and global impairment in several areas of human development and demands extensive care and dependence on the parents. The objective of this study was to understand the perceptions of mothers of children with autism regarding changes suffered by the child and their trajectories in search of an autism diagnosis. This is an exploratory descriptive study with a qualitative approach conducted with ten participant mothers. Data were collected in 2013 by means of semi-structured interviews. Thematic content analysis produced the following categories: perceptions of mothers as to changes in behaviour and/or development of their children; and trajectories of mothers in search of a diagnosis for their children. After the perception of changes in behaviour/development, mothers face an arduous trajectory of healthcare service utilization.

  17. Quantum trajectories: Memory and continuous observation

    Science.gov (United States)

    Barchielli, Alberto; Pellegrini, Clément; Petruccione, Francesco

    2012-12-01

    Starting from a generalization of the quantum trajectory theory [based on the stochastic Schrödinger equation (SSE)], non-Markovian models of quantum dynamics are derived. In order to describe non-Markovian effects, the approach used in this article is based on the introduction of random coefficients in the usual linear SSE. A major interest is that this allows a consistent theory of quantum measurement in continuous time to be developed for these non-Markovian quantum trajectory models. In this context, the notions of “instrument,” “a priori,” and “a posteriori” states can be introduced. The key point is that by starting from a stochastic equation on the Hilbert space of the system, we are able to respect the complete positivity of the mean dynamics for the statistical operator and the requirements of the axioms of quantum measurement theory. The flexibility of the theory is next illustrated by a concrete physical model of a noisy oscillator where non-Markovian effects come from the random environment, colored noises, randomness in the stimulating light, and delay effects. The statistics of the emitted photons and the heterodyne and homodyne spectra are studied, and we show how these quantities are sensitive to the non-Markovian features of the system dynamics, so that, in principle, the observation and analysis of the fluorescent light could reveal the presence of non-Markovian effects and allow for a measure of the spectra of the noises affecting the system dynamics.

  18. Distinguished trajectories in time dependent vector fields

    OpenAIRE

    Madrid, J. A. Jimenez; Mancho, Ana M.

    2008-01-01

    We introduce a new definition of distinguished trajectory that generalizes the concepts of fixed point and periodic orbit to aperiodic dynamical systems. This new definition is valid for identifying distinguished trajectories with hyperbolic and nonhyperbolic types of stability. The definition is implemented numerically and the procedure consists of determining a path of limit coordinates. It has been successfully applied to known examples of distinguished trajectories. In the context of high...

  19. Decentralized flight trajectory planning of multiple aircraft

    OpenAIRE

    Yokoyama, Nobuhiro; 横山 信宏

    2008-01-01

    Conventional decentralized algorithms for optimal trajectory planning tend to require prohibitive computational time as the number of aircraft increases. To overcome this drawback, this paper proposes a novel decentralized trajectory planning algorithm adopting a constraints decoupling approach for parallel optimization. The constraints decoupling approach is formulated as the path constraints of the real-time trajectory optimization problem based on nonlinear programming. Due to the parallel...

  20. In situ data analytics and indexing of protein trajectories.

    Science.gov (United States)

    Johnston, Travis; Zhang, Boyu; Liwo, Adam; Crivelli, Silvia; Taufer, Michela

    2017-06-15

    The transition toward exascale computing will be accompanied by a performance dichotomy. Computational peak performance will rapidly increase; I/O performance will either grow slowly or be completely stagnant. Essentially, the rate at which data are generated will grow much faster than the rate at which data can be read from and written to the disk. MD simulations will soon face the I/O problem of efficiently writing to and reading from disk on the next generation of supercomputers. This article targets MD simulations at the exascale and proposes a novel technique for in situ data analysis and indexing of MD trajectories. Our technique maps individual trajectories' substructures (i.e., α-helices, β-strands) to metadata frame by frame. The metadata captures the conformational properties of the substructures. The ensemble of metadata can be used for automatic, strategic analysis within a trajectory or across trajectories, without manually identify those portions of trajectories in which critical changes take place. We demonstrate our technique's effectiveness by applying it to 26.3k helices and 31.2k strands from 9917 PDB proteins and by providing three empirical case studies. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  1. CFD Analysis of Swing of Cricket Ball and Trajectory Prediction

    Science.gov (United States)

    G, Jithin; Tom, Josin; Ruishikesh, Kamat; Jose, Jyothish; Kumar, Sanjay

    2013-11-01

    This work aims to understand the aerodynamics associated with the flight and swing of a cricket ball and predict its flight trajectory over the course of the game: at start (smooth ball) and as the game progresses (rough ball). Asymmetric airflow over the ball due to seam orientation and surface roughness can cause flight deviation (swing). The values of Drag, Lift and Side forces which are crucial for determining the trajectory of the ball were found with the help of FLUENT using the standard K- ɛ model. Analysis was done to study how the ball velocity, spin imparted to be ball and the tilt of the seam affects the movement of the ball through air. The governing force balance equations in 3 dimensions in combination a MATLAB code which used Heun's method was used for obtaining the trajectory of the ball. The conditions for the conventional swing and reverse swing to occur were deduced from the analysis and found to be in alignment with the real life situation. Critical seam angle for maximum swing and transition speed for normal to reverse swing were found out. The obtained trajectories were compared to real life hawk eye trajectories for validation. The analysis results were in good agreement with the real life situation.

  2. Antecedents of transition patterns of depressive symptom trajectories from adolescence to young adulthood.

    Science.gov (United States)

    Lee, Tae Kyoung; Wickrama, Kandauda A S; Kwon, Josephine A; Lorenz, Frederick O; Oshri, Assaf

    2017-11-01

    This study examined (a) transition patterns from adolescent-specific depressive symptom trajectory classes to young adult-specific trajectory classes (N = 537; 15-26 years) and (b) identified risk factors associated with these transition patterns. The latent classes and transition analyses identified three transitional patterns of depressive symptom trajectories, including a deteriorating pattern (8.2%), a recovering pattern (22.5%), and a consistently low pattern (69.3%). Additionally, the results showed that contextual risk factors (i.e., negative economic events, negative romantic relationships, and low college enrolment rates) in the transition period to young adulthood were more positively associated with deteriorated or recovered transition patterns of depressive symptom trajectories than with the consistently low transition patterns even after taking into account the effects of adolescent risk factors. The identification of dynamic transition patterns in depressive symptom trajectories from adolescence to young adulthood and risk factors provide useful tools for preventive and intervention efforts. Statement of contribution What is already known on this subject? Heterogeneous trajectories of depressive symptoms across adolescence and young adulthood have been reported. Psychosocial characteristics differentiate trajectories of depressive symptoms from adolescence to young adulthood. What does this study add? Dynamic transition patterns of depressive symptom trajectories are found between adolescence and young adulthood. Life experiences in the transition period are uniquely associated with the transition patterns of depressive symptom trajectories even after adjusting the effects of adolescent characteristics. © 2017 The British Psychological Society.

  3. Trajectories and models of individual growth

    Directory of Open Access Journals (Sweden)

    Arseniy Karkach

    2006-11-01

    Full Text Available It has long been recognized that the patterns of growth play an important role in the evolution of age trajectories of fertility and mortality (Williams, 1957. Life history studies would benefit from a better understanding of strategies and mechanisms of growth, but still no comparative research on individual growth strategies has been conducted. Growth patterns and methods have been shaped by evolution and a great variety of them are observed. Two distinct patterns - determinate and indeterminate growth - are of a special interest for these studies since they present qualitatively different outcomes of evolution. We attempt to draw together studies covering growth in plant and animal species across a wide range of phyla focusing primarily on the noted qualitative features. We also review mathematical descriptions of growth, namely empirical growth curves and growth models, and discuss the directions of future research.

  4. A Qualitative Exploration of Trajectories among Suburban Users of Methamphetamine

    Science.gov (United States)

    Boeri, Miriam Williams; Harbry, Liam; Gibson, David

    2009-01-01

    The goal of this exploratory study was to gain a better understanding of methamphetamine use among suburban users. We know very little about the mechanisms of initiation and trajectory patterns of methamphetamine use among this under-researched and hidden population. This study employed qualitative methods to examine the drug career of suburban…

  5. Geometrical properties of systems with spiral trajectories in R^3

    Directory of Open Access Journals (Sweden)

    Luka Korkut

    2015-10-01

    Full Text Available We study a class of second-order nonautonomous differential equations, and the corresponding planar and spatial systems, from the geometrical point of view. The oscillatory behavior of solutions at infinity is measured by oscillatory and phase dimensions, The oscillatory dimension is defined as the box dimension of the reflected solution near the origin, while the phase dimension is defined as the box dimension of a trajectory of the planar system in the phase plane. Using the phase dimension of the second-order equation we compute the box dimension of a spiral trajectory of the spatial system. This phase dimension of the second-order equation is connected to the asymptotic of the associated Poincare map. Also, the box dimension of a trajectory of the reduced normal form with one eigenvalue equals zero, and a pair of pure imaginary eigenvalues is computed when limit cycles bifurcate from the origin.

  6. Entangled trajectories Hamiltonian dynamics for treating quantum nuclear effects

    Science.gov (United States)

    Smith, Brendan; Akimov, Alexey V.

    2018-04-01

    A simple and robust methodology, dubbed Entangled Trajectories Hamiltonian Dynamics (ETHD), is developed to capture quantum nuclear effects such as tunneling and zero-point energy through the coupling of multiple classical trajectories. The approach reformulates the classically mapped second-order Quantized Hamiltonian Dynamics (QHD-2) in terms of coupled classical trajectories. The method partially enforces the uncertainty principle and facilitates tunneling. The applicability of the method is demonstrated by studying the dynamics in symmetric double well and cubic metastable state potentials. The methodology is validated using exact quantum simulations and is compared to QHD-2. We illustrate its relationship to the rigorous Bohmian quantum potential approach, from which ETHD can be derived. Our simulations show a remarkable agreement of the ETHD calculation with the quantum results, suggesting that ETHD may be a simple and inexpensive way of including quantum nuclear effects in molecular dynamics simulations.

  7. Optimization of Vehicular Trajectories under Gaussian Noise Disturbances

    Directory of Open Access Journals (Sweden)

    Joan Garcia-Haro

    2012-12-01

    Full Text Available Nowadays, research on Vehicular Technology aims at automating every single mechanical element of vehicles, in order to increase passengers’ safety, reduce human driving intervention and provide entertainment services on board. Automatic trajectory tracing for vehicles under especially risky circumstances is a field of research that is currently gaining enormous attention. In this paper, we show some results on how to develop useful policies to execute maneuvers by a vehicle at high speeds with the mathematical optimization of some already established mobility conditions of the car. We also study how the presence of Gaussian noise on measurement sensors while maneuvering can disturb motion and affect the final trajectories. Different performance criteria for the optimization of such maneuvers are presented, and an analysis is shown on how path deviations can be minimized by using trajectory smoothing techniques like the Kalman Filter. We finalize the paper with a discussion on how communications can be used to implement these schemes.

  8. Trajectories and Maneuvers of Surrounding Vehicles with Panoramic Camera Arrays

    DEFF Research Database (Denmark)

    Dueholm, Jacob Velling; Kristoffersen, Miklas Strøm; Satzoda, Ravi K.

    2016-01-01

    Vision-based research for intelligent vehicles have traditionally focused on specific regions around a vehicle, such as a front looking camera for, e.g., lane estimation. Traffic scenes are complex and vital information could be lost in unobserved regions. This paper proposes a framework that uses...... four visual sensors for a full surround view of a vehicle in order to achieve an understanding of surrounding vehicle behaviors. The framework will assist the analysis of naturalistic driving studies by automating the task of data reduction of the observed trajectories. To this end, trajectories...... are estimated using a vehicle detector together with a multiperspective optimized tracker in each view. The trajectories are transformed to a common ground plane, where they are associated between perspectives and analyzed to reveal tendencies around the ego-vehicle. The system is tested on sequences from 2.5 h...

  9. A Model of Organizational Trajectories to Innovation Management

    Directory of Open Access Journals (Sweden)

    Alvair Silveira Torres Jr.

    2007-03-01

    Full Text Available The multiple-case study research in three industrial companies - located in Brazil- about organizational changing, comparing cases of lean production system implementation, revealed a suggested interpretation of the determinants and directions of organizational innovation. The model tries to account for both continuous changes and discontinuities in organizational innovation. Continuous changes are related to secondary innovation, which doesn’t break an organizational paradigm, while discontinuities are associated with a new trajectory, since a primary innovation adopted by the whole organization. Then, the innovative lean process associated with secondary innovation was inadequate to change the organizational trajectory and it explains the cyclical decisions. On the other hand, the lean production system related to primary innovation, assumes the role as a new trajectory, influencing changes in total organization. The greatest difference found in the companies for innovative diffusion process, was the aspect of spread the organizational principles or a simple set of management’s tools.

  10. Learning and Correcting Robot Trajectory Keypoints from a Single Demonstration

    DEFF Research Database (Denmark)

    Juan, Iñigo Iturrate San; Østergaard, Esben Hallundbæk; Rytter, Martin

    2017-01-01

    of a trajectory from a single demonstration. Additionally, by utilizing velocity information in the task space, the method is able to achieve a level of precision that is sufficient for industrial assembly tasks. Along with this, we present a user study that shows that our method enables non-expert robot users......Kinesthetic teaching provides an accessible way for non-experts to quickly and easily program a robot system by demonstration. A crucial aspect of this technique is to obtain an accurate approximation of the robot’s intended trajectory for the task, while filtering out spurious aspects...... of the demonstration. While several methods to this end have been proposed, they either rely on several demonstrations or on the user explicitly indicating relevant trajectory waypoints. We propose a method, based on the Douglas-Peucker line simplification algorithm that is able to extract the notable points...

  11. Mental retirement? Trajectories of work engagement preceding retirement among older workers

    NARCIS (Netherlands)

    Wind, A. de; Leijten, F.R.M.; Hoekstra, T.; Geuskens, G.A.; Burdorf, L.; Beek, A.J. van der

    2017-01-01

    Objectives Before actual retirement, employees may already distance themselves from work, which could be referred to as "mental retirement". However, trajectories of work motivation, ie, work engagement, have not been studied yet. The present study aimed to (i) identify different trajectories of

  12. Asymptotic behaviour of unbounded trajectories for some non-autonomous systems in a Hilbert space

    International Nuclear Information System (INIS)

    Djafari Rouhani, B.

    1990-07-01

    The asymptotic behaviour of unbounded trajectories for non expansive mappings in a real Hilbert space and the extension to more general Banach spaces and to nonlinear contraction semi-group have been studied by many authors. In this paper we study the asymptotic behaviour of unbounded trajectories for a quasi non-autonomous dissipative systems. 26 refs

  13. 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...... data is anonymized in the system using data cloaking and data swapping techniques. Finally, the paper empirically demonstrates that the proposed system is effective and feasible....

  14. Mobility, Education and Life Trajectories

    DEFF Research Database (Denmark)

    Olwig, Karen Fog; Valentin, Karen

    2015-01-01

    Travel for educational purposes, once the privilege of the upper class, has become a global mass phenomenon in recent years. This special issue examines, within different cultural and historical contexts, the close relationship between migration, education and social mobility. Adopting...... 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...

  15. Entanglement evolution for quantum trajectories

    International Nuclear Information System (INIS)

    Vogelsberger, S; Spehner, D

    2011-01-01

    Entanglement is a key resource in quantum information. It can be destroyed or sometimes created by interactions with a reservoir. In recent years, much attention has been devoted to the phenomena of entanglement sudden death and sudden birth, i.e., the sudden disappearance or revival of entanglement at finite times resulting from a coupling of the quantum system to its environment. We investigate the evolution of the entanglement of noninteracting qubits coupled to reservoirs under monitoring of the reservoirs by means of continuous measurements. Because of these measurements, the qubits remain at all times in a pure state, which evolves randomly. To each measurement result (or 'realization') corresponds a quantum trajectory in the Hilbert space of the qubits. We show that for two qubits coupled to independent baths subjected to local measurements, the average of the qubits' concurrence over all quantum trajectories is either constant or decays exponentially. The corresponding decay rate depends on the measurement scheme only. This result contrasts with the entanglement sudden death phenomenon exhibited by the qubits' density matrix in the absence of measurements. Our analysis applies to arbitrary quantum jump dynamics (photon counting) as well as to quantum state diffusion (homodyne or heterodyne detections) in the Markov limit. We discuss the best measurement schemes to protect the entanglement of the qubits. We also analyze the case of two qubits coupled to a common bath. Then, the average concurrence can vanish at discrete times and may coincide with the concurrence of the density matrix. The results explained in this article have been presented during the 'Fifth International Workshop DICE2010' by the first author and have been the subject of a prior publication.

  16. Technical description of the RIVM trajectory model

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, E.S.; Van Pul, W.A.J.

    1995-12-01

    The RIVM trajectory model, described in this report, enables calculation of a backward or forward trajectory. These trajectories are used to `follow` previous released air pollution in a backward mode or to `find` the origin of air pollution in a forward mode. The trajectories are used in the smog forecasting and in the TREND model for the distribution of materials in Europe. Presently 6-hourly ECMWF wind fields at 1000 and 850 hPa, with 3 deg x 3 deg latitude-longitude resolution are used. Wind fields with a different resolution in latitude-longitude can also be used after simple adjustments. An iterative method, described elsewhere, is applied to calculate the trajectories. Within limits, the user is free to choose the time step (1, 2 or 6-hour), transport height, length, starting or arrival date and starting or arrival position of the trajectory. The differences between the trajectories calculated with time steps of 1, 2 and 6 h were small. For the 96-hour trajectories at 1000 and 850 hPa the deviations were generally within 1 deg latitude and longitude, i.e. 100-200 km. The trajectory calculated with the 6-hour time step could be used without a great loss in accuracy compared to the calculations with the 1-hour time step. A typical error in the trajectory path at 1000 and 850 hPa was 500 km, which is about 30% of a typical travel distance. However, close to quickly changing weather systems, such as cyclones, the error can be as large as the travel distance and makes the calculations unreliable. The error in the forecasted trajectory was found to be larger than the above error estimation due to larger uncertainties in the forecasted compared to the analyzed wind fields. A manual on how to run the model is also given. 5 figs., 3 tabs., 5 refs., 6 appendices

  17. Trajectory control with continuous thrust applied to a rendezvous maneuver

    International Nuclear Information System (INIS)

    Santos, W G; Rocco, E M

    2013-01-01

    A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target

  18. Trajectory Design for a Single-String Impactor Concept

    Science.gov (United States)

    Dono Perez, Andres; Burton, Roland; Stupl, Jan; Mauro, David

    2017-01-01

    This paper introduces a trajectory design for a secondary spacecraft concept to augment science return in interplanetary missions. The concept consist of a single-string probe with a kinetic impactor on board that generates an artificial plume to perform in-situ sampling. The trajectory design was applied to a particular case study that samples ejecta particles from the Jovian moon Europa. Results were validated using statistical analysis. Details regarding the navigation, targeting and disposal challenges related to this concept are presented herein.

  19. Review on abort trajectory for manned lunar landing mission

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Abort trajectory is a passage that ensures the astronauts to return safely to the earth when an emergency occurs. Firstly,the essential elements of mission abort are analyzed entirely based on summarizing the existing studies. Then,abort trajectory requirement and rational selection for different flight phases of typical manned lunar mission are discussed specifically. Considering a trade-off between the two primary constrains of an abort,the return time of flight and energy requirement,a general optimizing method for mission abort is proposed. Finally,some suggestions are given for China’s future manned lunar landing mission.

  20. Zipf exponent of trajectory distribution in the hidden Markov model

    Science.gov (United States)

    Bochkarev, V. V.; Lerner, E. Yu

    2014-03-01

    This paper is the first step of generalization of the previously obtained full classification of the asymptotic behavior of the probability for Markov chain trajectories for the case of hidden Markov models. The main goal is to study the power (Zipf) and nonpower asymptotics of the frequency list of trajectories of hidden Markov frequencys and to obtain explicit formulae for the exponent of the power asymptotics. We consider several simple classes of hidden Markov models. We prove that the asymptotics for a hidden Markov model and for the corresponding Markov chain can be essentially different.