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Sample records for trajectory post-mi assessment

  1. Assessing the performance of dynamical trajectory estimates

    Science.gov (United States)

    Bröcker, Jochen

    2014-06-01

    Estimating trajectories and parameters of dynamical systems from observations is a problem frequently encountered in various branches of science; geophysicists for example refer to this problem as data assimilation. Unlike as in estimation problems with exchangeable observations, in data assimilation the observations cannot easily be divided into separate sets for estimation and validation; this creates serious problems, since simply using the same observations for estimation and validation might result in overly optimistic performance assessments. To circumvent this problem, a result is presented which allows us to estimate this optimism, thus allowing for a more realistic performance assessment in data assimilation. The presented approach becomes particularly simple for data assimilation methods employing a linear error feedback (such as synchronization schemes, nudging, incremental 3DVAR and 4DVar, and various Kalman filter approaches). Numerical examples considering a high gain observer confirm the theory.

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

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    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.

  3. The importance of trajectory modelling in accident consequence assessments

    International Nuclear Information System (INIS)

    Jones, J.A.; Williams, J.A.; Hill, M.D.

    1988-01-01

    Most atmospheric dispersion models used at present or probabilistic risk assessment (PRA) are linear: they take account of the wind speed but not the direction after the first hour. Therefore, the trajectory model is a more realistic description of the cloud's behaviour. However, the extra complexity means that the computing costs increase. This is an important factor for the MARIA code which is intended to be run on computers of varying power. The numbers of early effects predicted by a linear model and a trajectory model in a probabilistic risk assessment were compared to see which model should be preferred. The trajectory model predicted about 25% fewer expected early deaths and 30% more people evacuated than the linear model. However, the trajectory model took about ten times longer to calculate its results. The choice between the two models may depend on the speed of the computer available

  4. Post-MI depression and levels of serum IL-6 and CRP in AMI patients

    International Nuclear Information System (INIS)

    Huang Tiejun

    2004-01-01

    Objective: To explore the relationship between the presence and severity of post-MI depression and the increased inflammatory activity, as marked by the serum levels of interleukin-6 (IL-6) and C-reactive protein (CRP) after myocardial infarction. Methods: Serum IL-6 and CRP levels were measured in 58 AMI patients within 36 hours after onset of event. Depression was evaluated by self-reporting standardized questionnaire, using a validated Chinese version of Hospiatla Anxiety and Depression Scale (HADS)-Depression Subscale (7 items) within 7 days. Demographic and medical data including LVEF, NYHA cardiac function grading, atherosclerosis severity shown from angiography as well as cardiac risk factors were recorded. Results: Serum levels of IL-6 and CRP were higher in depressive AMI patients than those in non-depressive ones (0.93 ± 0.64 vs 0.48 ± 0.37 ng/L, P<0.05 and 0.96 ± 0.41 vs 0.47 ± 0.26 mg/dL, P<0.05). Neither levels of IL-6 nor HADS-D scores were found to be correlated to the severity of atherosclerosis shown in angiography. Conclusion: Presence and severity of post-MI depression is associated with increased activity of inflammation in patients after myocardial infarction. (authors)

  5. Trajectories of Psychosocial Problems in Adolescents Predicted by Findings From Early Well-Child Assessments

    NARCIS (Netherlands)

    Jaspers, Merlijne; de Winter, Andrea F.; Huisman, Mark; Verhulst, Frank C.; Ormel, Johan; Stewart, Roy E.; Reijneveld, Sijmen A.

    2012-01-01

    Purpose: To describe trajectories of emotional and behavioral problems in adolescents and to identify early indicators of these trajectories using data from routine well-child assessments at ages 0-4 years. Methods: Data from three assessment waves of adolescents (n = 1,816) of the TRAILS were used

  6. Cost, Time, and Risk Assessment of Different Wave Energy Converter Technology Development Trajectories: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Jochem W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Laird, Daniel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Costello, Ronan [Wave Venture; Roberts, Jesse [Sandia National Laboratories; Bull, Diana [Sandia National Laboratories; Babarit, Aurelien [Ecole Centrale de Nantes; Nielsen, Kim [Ramboll; Ferreira, Claudio Bittencourt [DNV-GL; Kennedy, Ben [Wave Venture

    2017-09-14

    This paper presents a comparative assessment of three fundamentally different wave energy converter technology development trajectories. The three technology development trajectories are expressed and visualised as a function of technology readiness levels and technology performance levels. The assessment shows that development trajectories that initially prioritize technology readiness over technology performance are likely to require twice the development time, consume a threefold of the development cost, and are prone to a risk of technical or commercial failure of one order of magnitude higher than those development trajectories that initially prioritize technology performance over technology readiness.

  7. Applications of Trajectory Solid Angle for Probabilistic Safety Assessment

    International Nuclear Information System (INIS)

    Wong, Po Kee; Wong, Adam E.; Wong, Anita

    2002-01-01

    In 1974, a well-known research problem in Statistical Mechanics entitled 'To determine and define the probability function P.sub.2 of a particle hitting a predetermined area, given all its parameters of generation and ejection' was openly solicited for its solution from research and development organizations in U.S.A. One of many proposed solutions of the problem, initiated at that time, is by means of the Trajectory Solid Angle (TSA). TSA is defined as the integral of the dot product of the unit tangent of the particle's trajectory to the vector area divided by the square of the position vector connecting between the point of ejection and that of the surface to be hit. The invention provides: (1) The precise and the unique solution of a previously unsolved P.sub.2 problem: (2) Impacts to the governmental NRC safety standards and DOD weapon systems and many activities in the Department of Energy; (3) Impacts to update the contents of text books of physics and mathematics of all levels; (4) Impacts to the scientific instruments with applications in high technologies. The importance of Trajectory Solid Angle can be quoted from a letter by the late Institute Professor P. M. Morse of MIT who reviewed the DOE proposal P7900450 (reference No. 7) in 1979 and addressed to the inventor. 'If the Trajectory Solid Angle is correct it will provide a revolutionary concept in physics'. (authors)

  8. A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories

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    Sigrun Matthes

    2017-08-01

    Full Text Available Comprehensive assessment of the environmental aspects of flight movements is of increasing interest to the aviation sector as a potential input for developing sustainable aviation strategies that consider climate impact, air quality and noise issues simultaneously. However, comprehensive assessments of all three environmental aspects do not yet exist and are in particular not yet operational practice in flight planning. The purpose of this study is to present a methodology which allows to establish a multi-criteria environmental impact assessment directly in the flight planning process. The method expands a concept developed for climate optimisation of aircraft trajectories, by representing additionally air quality and noise impacts as additional criteria or dimensions, together with climate impact of aircraft trajectory. We present the mathematical framework for environmental assessment and optimisation of aircraft trajectories. In that context we present ideas on future implementation of such advanced meteorological services into air traffic management and trajectory planning by relying on environmental change functions (ECFs. These ECFs represent environmental impact due to changes in air quality, noise and climate impact. In a case study for Europe prototype ECFs are implemented and a performance assessment of aircraft trajectories is performed for a one-day traffic sample. For a single flight fuel-optimal versus climate-optimized trajectory solution is evaluated using prototypic ECFs and identifying mitigation potential. The ultimate goal of such a concept is to make available a comprehensive assessment framework for environmental performance of aircraft operations, by providing key performance indicators on climate impact, air quality and noise, as well as a tool for environmental optimisation of aircraft trajectories. This framework would allow studying and characterising changes in traffic flows due to environmental optimisation, as well

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

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    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…

  10. Preliminary Assessment of Operational Hazards and Safety Requirements for Airborne Trajectory Management (ABTM) Roadmap Applications

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    Cotton, William B.; Hilb, Robert; Koczo, Stefan, Jr.; Wing, David J.

    2016-01-01

    A set of five developmental steps building from the NASA TASAR (Traffic Aware Strategic Aircrew Requests) concept are described, each providing incrementally more efficiency and capacity benefits to airspace system users and service providers, culminating in a Full Airborne Trajectory Management capability. For each of these steps, the incremental Operational Hazards and Safety Requirements are identified for later use in future formal safety assessments intended to lead to certification and operational approval of the equipment and the associated procedures. Two established safety assessment methodologies that are compliant with the FAA's Safety Management System were used leading to Failure Effects Classifications (FEC) for each of the steps. The most likely FEC for the first three steps, Basic TASAR, Digital TASAR, and 4D TASAR, is "No effect". For step four, Strategic Airborne Trajectory Management, the likely FEC is "Minor". For Full Airborne Trajectory Management (Step 5), the most likely FEC is "Major".

  11. The Right Trajectory: State Teachers of the Year Compare Former and New State Assessments

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    McClellan, Catherine; Joe, Jilliam; Bassett, Katherine

    2015-01-01

    "The Right Trajectory" brings to the forefront an often-overlooked voice in the debate about new state assessments developed in consortia: that of the best teachers in the country. This research suggests, despite challenges still to overcome, that these front-line experts believe that the new consortia tests are an improvement on the…

  12. Stability Assessment as a Criterion of Stabilization of the Movement Trajectory of Mobile Crane Working Elements

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    Kacalak, W.; Budniak, Z.; Majewski, M.

    2018-02-01

    The article presents a stability assessment method of the mobile crane handling system based on the safety indicator values that were accepted as the trajectory optimization criterion. With the use of the mathematical model built and the model built in the integrated CAD/CAE environment, analyses were conducted of the displacements of the mass centre of the crane system, reactions of the outrigger system, stabilizing and overturning torques that act on the crane as well as the safety indicator values for the given movement trajectories of the crane working elements.

  13. CT-based bone density assessment for iliosacral screw trajectories

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    Andreas Schicho

    2016-01-01

    Full Text Available Introduction: Sacroiliac screw placement is one standard treatment option for stabilization of posterior pelvic ring injuries encountering high intra- and inter-individual variations of bone stock quality as well as a vast variety and prevalence of sacral dysmorphism. An individual, easy-to-use preoperative bone stock quality estimation would be of high value for the surgeon. Materials and Methods: We analyzed 36 standard computed tomography datasets with the uninjured pelvic ring. Using a two-plane cross-referencing technique, we assessed the Hounsfield unit (HU mean values as well as standard deviation and minimum/maximum values within selected region of interests (ROIs at five key areas: os ilium left and right, massa lateralis of os sacrum left and right, and central vertebral body on levels S1 and S2. Results: Results showed no difference in mean HU at any ROI when comparing male and female data. For all ROIs set on S1 and S2, there was an age-related decline of HU with a calculated slope significantly different from zero. There was no statistical difference of slopes when comparing S1- and S2-level with respect to any distinct ROI. Comparison of levels S1 and S2 revealed differences at the vertebral body and at the right os ilium. The right and left massa lateralis of os sacrum had lower bone density than the center of the vertebral body, the right, or left os ilium on S1; right and left massa lateralis density did not differ significantly. On level S2, results were comparable with no difference of massa lateralis density. Conclusion: With our easy-to-use preoperative assessment of bone density of five key areas of sacroiliac screw anchoring we were able to find the lowest bone density in both the left and right massa lateralis on levels S1 and S2 with high inter- and intra-individual variations. Significantly lower bone density was found in the center of the vertebral bodies S2 in comparison to S1, which both are crucial for iliosacral

  14. Intelligent Aircraft Damage Assessment, Trajectory Planning, and Decision-Making under Uncertainty

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    Lopez, Israel; Sarigul-Klijn, Nesrin

    Situational awareness and learning are necessary to identify and select the optimal set of mutually non-exclusive hypothesis in order to maximize mission performance and adapt system behavior accordingly. This paper presents a hierarchical and decentralized approach for integrated damage assessment and trajectory planning in aircraft with uncertain navigational decision-making. Aircraft navigation can be safely accomplished by properly addressing the following: decision-making, obstacle perception, aircraft state estimation, and aircraft control. When in-flight failures or damage occur, rapid and precise decision-making under imprecise information is required in order to regain and maintain control of the aircraft. To achieve planned aircraft trajectory and complete safe landing, the uncertainties in system dynamics of the damaged aircraft need to be learned and incorporated at the level of motion planning. The damaged aircraft is simulated via a simplified kinematic model. The different sources and perspectives of uncertainties in the damage assessment process and post-failure trajectory planning are presented and classified. The decision-making process for an emergency motion planning and landing is developed via the Dempster-Shafer evidence theory. The objective of the trajectory planning is to arrive at a target position while maximizing the safety of the aircraft given uncertain conditions. Simulations are presented for an emergency motion planning and landing that takes into account aircraft dynamics, path complexity, distance to landing site, runway characteristics, and subjective human decision.

  15. Trajectory Assessment and Modification Tools for Next Generation Air Traffic Management Operations

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    Brasil, Connie; Lee, Paul; Mainini, Matthew; Lee, Homola; Lee, Hwasoo; Prevot, Thomas; Smith, Nancy

    2011-01-01

    This paper reviews three Next Generation Air Transportation System (NextGen) based high fidelity air traffic control human-in-the-loop (HITL) simulations, with a focus on the expected requirement of enhanced automated trajectory assessment and modification tools to support future air traffic flow management (ATFM) planning positions. The simulations were conducted at the National Aeronautics and Space Administration (NASA) Ames Research Centers Airspace Operations Laboratory (AOL) in 2009 and 2010. The test airspace for all three simulations assumed the mid-term NextGenEn-Route high altitude environment utilizing high altitude sectors from the Kansas City and Memphis Air Route Traffic Control Centers. Trajectory assessment, modification and coordination decision support tools were developed at the AOL in order to perform future ATFM tasks. Overall tool usage results and user acceptability ratings were collected across three areas of NextGen operatoins to evaluate the tools. In addition to the usefulness and usability feedback, feasibility issues, benefits, and future requirements were also addressed. Overall, the tool sets were rated very useful and usable, and many elements of the tools received high scores and were used frequently and successfully. Tool utilization results in all three HITLs showed both user and system benefits including better airspace throughput, reduced controller workload, and highly effective communication protocols in both full Data Comm and mixed-equipage environments.

  16. Assembly Line Productivity Assessment by Comparing Optimization-Simulation Algorithms of Trajectory Planning for Industrial Robots

    Directory of Open Access Journals (Sweden)

    Francisco Rubio

    2015-01-01

    Full Text Available In this paper an analysis of productivity will be carried out from the resolution of the problem of trajectory planning of industrial robots. The analysis entails economic considerations, thus overcoming some limitations of the existing literature. Two methodologies based on optimization-simulation procedures are compared to calculate the time needed to perform an industrial robot task. The simulation methodology relies on the use of robotics and automation software called GRASP. The optimization methodology developed in this work is based on the kinematics and the dynamics of industrial robots. It allows us to pose a multiobjective optimization problem to assess the trade-offs between the economic variables by means of the Pareto fronts. The comparison is carried out for different examples and from a multidisciplinary point of view, thus, to determine the impact of using each method. Results have shown the opportunity costs of non using the methodology with optimized time trajectories. Furthermore, it allows companies to stay competitive because of the quick adaptation to rapidly changing markets.

  17. Variable trajectory model for regional assessments of air pollution from sulfur compounds.

    Energy Technology Data Exchange (ETDEWEB)

    Powell, D.C.; McNaughton, D.J.; Wendell, L.L.; Drake, R.L.

    1979-02-01

    This report describes a sulfur oxides atmospheric pollution model that calculates trajectories using single-layer historical wind data as well as chemical transformation and deposition following discrete contaminant air masses. Vertical diffusion under constraints is calculated, but all horizontal dispersion is a funcion of trajectory variation. The ground-level air concentrations and deposition are calculated in a rectangular area comprising the northeastern United States and southeastern Canada. Calculations for a 29-day assessment period in April 1974 are presented along with a limited verification. Results for the studies were calculated using a source inventory comprising 61% of the anthropogenic SO/sub 2/ emissions. Using current model parameterization levels, predicted concentration values are most sensitive to variations in dry deposition of SO/sub 2/, wet deposition of sulfate, and transformation of SO/sub 2/ to sulfate. Replacing the variable mixed-layer depth and variable stability features of the model with constant definitions of each results in increased ground-level concentration predicions for SO/sub 2/ and particularly for sulfate.

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

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    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.

  19. Introducing the fit-criteria assessment plot - A visualisation tool to assist class enumeration in group-based trajectory modelling.

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    Klijn, Sven L; Weijenberg, Matty P; Lemmens, Paul; van den Brandt, Piet A; Lima Passos, Valéria

    2017-10-01

    Background and objective Group-based trajectory modelling is a model-based clustering technique applied for the identification of latent patterns of temporal changes. Despite its manifold applications in clinical and health sciences, potential problems of the model selection procedure are often overlooked. The choice of the number of latent trajectories (class-enumeration), for instance, is to a large degree based on statistical criteria that are not fail-safe. Moreover, the process as a whole is not transparent. To facilitate class enumeration, we introduce a graphical summary display of several fit and model adequacy criteria, the fit-criteria assessment plot. Methods An R-code that accepts universal data input is presented. The programme condenses relevant group-based trajectory modelling output information of model fit indices in automated graphical displays. Examples based on real and simulated data are provided to illustrate, assess and validate fit-criteria assessment plot's utility. Results Fit-criteria assessment plot provides an overview of fit criteria on a single page, placing users in an informed position to make a decision. Fit-criteria assessment plot does not automatically select the most appropriate model but eases the model assessment procedure. Conclusions Fit-criteria assessment plot is an exploratory, visualisation tool that can be employed to assist decisions in the initial and decisive phase of group-based trajectory modelling analysis. Considering group-based trajectory modelling's widespread resonance in medical and epidemiological sciences, a more comprehensive, easily interpretable and transparent display of the iterative process of class enumeration may foster group-based trajectory modelling's adequate use.

  20. Trajectories of Depressive Symptoms Among Web-Based Health Risk Assessment Participants.

    Science.gov (United States)

    Bedrosian, Richard; Hawrilenko, Matt; Cole-Lewis, Heather

    2017-03-31

    Health risk assessments (HRAs), which often screen for depressive symptoms, are administered to millions of employees and health plan members each year. HRA data provide an opportunity to examine longitudinal trends in depressive symptomatology, as researchers have done previously with other populations. The primary research questions were: (1) Can we observe longitudinal trajectories in HRA populations like those observed in other study samples? (2) Do HRA variables, which primarily reflect modifiable health risks, help us to identify predictors associated with these trajectories? (3) Can we make meaningful recommendations for population health management, applicable to HRA participants, based on predictors we identify? This study used growth mixture modeling (GMM) to examine longitudinal trends in depressive symptomatology among 22,963 participants in a Web-based HRA used by US employers and health plans. The HRA assessed modifiable health risks and variables such as stress, sleep, and quality of life. Five classes were identified: A "minimal depression" class (63.91%, 14,676/22,963) whose scores were consistently low across time, a "low risk" class (19.89%, 4568/22,963) whose condition remained subthreshold, a "deteriorating" class (3.15%, 705/22,963) who began at subthreshold but approached severe depression by the end of the study, a "chronic" class (4.71%, 1081/22,963) who remained highly depressed over time, and a "remitting" class (8.42%, 1933/22,963) who had moderate depression to start, but crossed into minimal depression by the end. Among those with subthreshold symptoms, individuals who were male (PInternet Research (http://www.jmir.org), 31.03.2017.

  1. Assessing the Relationship Between Chronic Health Conditions and Productivity Loss Trajectories

    Science.gov (United States)

    Pranksy, Glenn

    2014-01-01

    Objective: To examine the relationship between health conditions and the risk for membership in longitudinal trajectories of productivity loss. Methods: Trajectories of productivity loss from the ages of 25 to 44 years, previously identified in the National Longitudinal Survey of Youth (NLSY79), were combined with information on health conditions from the age 40 years health module in the NLSY79. Multinomial logistic regression was used to examine the relative risk of being in the low-risk, early-onset increasing risk, late-onset increasing risk, or high-risk trajectories compared with the no-risk trajectory for having various health conditions. Results: The trajectories with the greatest probability of productivity loss longitudinally had a greater prevalence of the individual health conditions and a greater total number of health conditions experienced. Conclusions: Health conditions are associated with specific longitudinal patterns of experiencing productivity loss. PMID:25479294

  2. Developmental trajectories of cerebrovascular reactivity in healthy children and young adults assessed with magnetic resonance imaging.

    Science.gov (United States)

    Leung, Jackie; Kosinski, Przemyslaw D; Croal, Paula L; Kassner, Andrea

    2016-05-15

    Cerebrovascular reactivity (CVR) reflects the vasodilatory reserve of cerebral resistance vessels. Normal development in children is associated with significant changes in blood pressure, cerebral blood flow (CBF) and cerebral oxygen metabolism. Therefore, it stands to reason that CVR will also undergo changes during this period. The study acquired magnetic resonance imaging measures of CVR and CBF in healthy children and young adults to trace their changes with age. We found that CVR changes in two phases, increasing with age until the mid-teens, followed by a decrease. Baseline CBF declined steadily with age. We conclude that CVR varies with age during childhood, which prompts future CVR studies involving children to take into account the effect of development. Cerebrovascular reactivity (CVR) reflects the vasculature's ability to accommodate changes in blood flow demand thereby serving as a critical imaging tool for mapping vascular reserve. Normal development is associated with extensive physiological changes in blood pressure, cerebral blood flow and cerebral metabolic rate of oxygen, all of which can affect CVR. Moreover, the evolution of these physiological parameters is most prominent during childhood. Therefore, the aim of this study was to use non-invasive magnetic resonance imaging (MRI) to characterize the developmental trajectories of CVR in healthy children and young adults, and relate them to changes in cerebral blood flow (CBF). Thirty-four healthy subjects (17 males, 17 females; age 9-30 years) underwent CVR assessment using blood oxygen level-dependent MRI in combination with a computer controlled CO2 stimulus. In addition, baseline CBF was measured with a pulsed arterial spin labelling sequence. CVR exhibited a gradual increase with age in both grey and white matter up to 14.7 years. After this break point, a negative correlation with age was detected. Baseline CBF maintained a consistent negative linear correlation across the entire age range

  3. Real-Time Trajectory Assessment and Abort Management for the X-33 Vehicle

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    Moise, M. C.; McCarter, J. W.; Mulqueen, J.

    2000-01-01

    The X-33 is a flying testbed to evaluate technologies and designs for a reusable Single Stage To Orbit (SSTO) production vehicle. Although it is sub-orbital, it is trans-atmospheric. This paper will discuss the abort capabilities, both commanded and autonomous, available to the X-33. The cornerstone of the abort capabilities is the Performance Monitor (PM) and it's supporting software. PM is an on-board 3-DOF simulation, which evaluates the vehicle ability to execute the current trajectory. The Abort Manager evaluates the results from PM, and, when indicated, computes and implements an abort trajectory.

  4. Automatic assessment of average diaphragm motion trajectory from 4DCT images through machine learning.

    Science.gov (United States)

    Li, Guang; Wei, Jie; Huang, Hailiang; Gaebler, Carl Philipp; Yuan, Amy; Deasy, Joseph O

    2015-12-01

    To automatically estimate average diaphragm motion trajectory (ADMT) based on four-dimensional computed tomography (4DCT), facilitating clinical assessment of respiratory motion and motion variation and retrospective motion study. We have developed an effective motion extraction approach and a machine-learning-based algorithm to estimate the ADMT. Eleven patients with 22 sets of 4DCT images (4DCT1 at simulation and 4DCT2 at treatment) were studied. After automatically segmenting the lungs, the differential volume-per-slice (dVPS) curves of the left and right lungs were calculated as a function of slice number for each phase with respective to the full-exhalation. After 5-slice moving average was performed, the discrete cosine transform (DCT) was applied to analyze the dVPS curves in frequency domain. The dimensionality of the spectrum data was reduced by using several lowest frequency coefficients ( f v ) to account for most of the spectrum energy (Σ f v 2 ). Multiple linear regression (MLR) method was then applied to determine the weights of these frequencies by fitting the ground truth-the measured ADMT, which are represented by three pivot points of the diaphragm on each side. The 'leave-one-out' cross validation method was employed to analyze the statistical performance of the prediction results in three image sets: 4DCT1, 4DCT2, and 4DCT1 + 4DCT2. Seven lowest frequencies in DCT domain were found to be sufficient to approximate the patient dVPS curves ( R = 91%-96% in MLR fitting). The mean error in the predicted ADMT using leave-one-out method was 0.3 ± 1.9 mm for the left-side diaphragm and 0.0 ± 1.4 mm for the right-side diaphragm. The prediction error is lower in 4DCT2 than 4DCT1, and is the lowest in 4DCT1 and 4DCT2 combined. This frequency-analysis-based machine learning technique was employed to predict the ADMT automatically with an acceptable error (0.2 ± 1.6 mm). This volumetric approach is not affected by the presence of the lung tumors

  5. Intra-myocardial injection of both growth factors and heart derived Sca-1+/CD31- cells attenuates post-MI LV remodeling more than does cell transplantation alone: neither intervention enhances functionally significant cardiomyocyte regeneration.

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    Full Text Available Insulin-like growth factor 1 (IGF-1 and hepatocyte growth factor (HGF are two potent cell survival and regenerative factors in response to myocardial injury (MI. We hypothesized that simultaneous delivery of IGF+HGF combined with Sca-1+/CD31- cells would improve the outcome of transplantation therapy in response to the altered hostile microenvironment post MI. One million adenovirus nuclear LacZ-labeled Sca-1+/CD31- cells were injected into the peri-infarction area after left anterior descending coronary artery (LAD ligation in mice. Recombinant mouse IGF-1+HGF was added to the cell suspension prior to the injection. The left ventricular (LV function was assessed by echocardiography 4 weeks after the transplantation. The cell engraftment, differentiation and cardiomyocyte regeneration were evaluated by histological analysis. Sca-1+/CD31- cells formed viable grafts and improved LV ejection fraction (EF (Control, 54.5+/-2.4; MI, 17.6+/-3.1; Cell, 28.2+/-4.2, n = 9, P<0.01. IGF+HGF significantly enhanced the benefits of cell transplantation as evidenced by increased EF (38.8+/-2.2; n = 9, P<0.01 and attenuated adverse structural remodeling. Furthermore, IGF+HGF supplementation increased the cell engraftment rate, promoted the transplanted cell survival, enhanced angiogenesis, and minimally stimulated endogenous cardiomyocyte regeneration in vivo. The in vitro experiments showed that IGF+HGF treatment stimulated Sca-1+/CD31- cell proliferation and inhibited serum free medium induced apoptosis. Supperarray profiling of Sca-1+/CD31- cells revealed that Sca-1+/CD31- cells highly expressed various trophic factor mRNAs and IGF+HGF treatment altered the mRNAs expression patterns of these cells. These data indicate that IGF-1+HGF could serve as an adjuvant to cell transplantation for myocardial repair by stimulating donor cell and endogenous cardiac stem cell survival, regeneration and promoting angiogenesis.

  6. Intra-myocardial injection of both growth factors and heart derived Sca-1+/CD31- cells attenuates post-MI LV remodeling more than does cell transplantation alone: neither intervention enhances functionally significant cardiomyocyte regeneration.

    Science.gov (United States)

    Wang, Xiaohong; Li, Qinglu; Hu, Qingsong; Suntharalingam, Piradeep; From, Arthur H L; Zhang, Jianyi

    2014-01-01

    Insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) are two potent cell survival and regenerative factors in response to myocardial injury (MI). We hypothesized that simultaneous delivery of IGF+HGF combined with Sca-1+/CD31- cells would improve the outcome of transplantation therapy in response to the altered hostile microenvironment post MI. One million adenovirus nuclear LacZ-labeled Sca-1+/CD31- cells were injected into the peri-infarction area after left anterior descending coronary artery (LAD) ligation in mice. Recombinant mouse IGF-1+HGF was added to the cell suspension prior to the injection. The left ventricular (LV) function was assessed by echocardiography 4 weeks after the transplantation. The cell engraftment, differentiation and cardiomyocyte regeneration were evaluated by histological analysis. Sca-1+/CD31- cells formed viable grafts and improved LV ejection fraction (EF) (Control, 54.5+/-2.4; MI, 17.6+/-3.1; Cell, 28.2+/-4.2, n = 9, Pcell transplantation as evidenced by increased EF (38.8+/-2.2; n = 9, Pcell engraftment rate, promoted the transplanted cell survival, enhanced angiogenesis, and minimally stimulated endogenous cardiomyocyte regeneration in vivo. The in vitro experiments showed that IGF+HGF treatment stimulated Sca-1+/CD31- cell proliferation and inhibited serum free medium induced apoptosis. Supperarray profiling of Sca-1+/CD31- cells revealed that Sca-1+/CD31- cells highly expressed various trophic factor mRNAs and IGF+HGF treatment altered the mRNAs expression patterns of these cells. These data indicate that IGF-1+HGF could serve as an adjuvant to cell transplantation for myocardial repair by stimulating donor cell and endogenous cardiac stem cell survival, regeneration and promoting angiogenesis.

  7. Orion Exploration Flight Test-1 Post-Flight Navigation Performance Assessment Relative to the Best Estimated Trajectory

    Science.gov (United States)

    Gay, Robert S.; Holt, Greg N.; Zanetti, Renato

    2016-01-01

    This paper details the post-flight navigation performance assessment of the Orion Exploration Flight Test-1 (EFT-1). Results of each flight phase are presented: Ground Align, Ascent, Orbit, and Entry Descent and Landing. This study examines the on-board Kalman Filter uncertainty along with state deviations relative to the Best Estimated Trajectory (BET). Overall the results show that the Orion Navigation System performed as well or better than expected. Specifically, the Global Positioning System (GPS) measurement availability was significantly better than anticipated at high altitudes. In addition, attitude estimation via processing GPS measurements along with Inertial Measurement Unit (IMU) data performed very well and maintained good attitude throughout the mission.

  8. Determinants of hospital fall rate trajectory groups: a longitudinal assessment of nurse staffing and organizational characteristics.

    Science.gov (United States)

    Everhart, Damian; Schumacher, Jessica R; Duncan, R Paul; Hall, Allyson G; Neff, Donna F; Shorr, Ronald I

    2014-01-01

    Patient falls in acute care hospitals represent a significant patient safety concern. Although cross-sectional studies have shown that fall rates vary widely between acute care hospitals, it is not clear whether hospital fall rates remain consistent over time. The aim of this study was to determine whether hospitals can be categorized into fall rate trajectory groups over time and to identify nurse staffing and hospital characteristics associated with hospital fall rate trajectory groups. We conducted a 54-month (July 2006-December 2010) longitudinal study of U.S. acute care general hospitals participating in the National Database for Nursing Quality Indicators (2007). We used latent class growth modeling to categorize hospitals into groups based on their long-term fall rates. Nurse staffing and hospital characteristics associated with membership in the highest hospital fall rate group were identified using logistic regression. A sample of 1,529 hospitals (mean fall rate of 3.65 per 1,000 patient days) contributed data to the analysis. Latent class growth modeling findings classified hospital into three groups based on fall rate trajectories: consistently high (mean fall rate of 4.96 per 1,000 patient days), consistently medium (mean fall rate of 3.63 per 1,000 patient days), and consistently low (mean fall rate of 2.50 per 1,000 patient days). Hospitals with higher total nurse staffing (odds ratio [OR] = 0.92, 95% confidence interval [CI] [0.85, 0.99]), Magnet status (OR = 0.49, 95% CI [0.35, 0.70]), and bed size greater than 300 beds (OR = 0.70, 95% CI [0.51, 0.94]) were significantly less likely to be categorized in the "consistently high" fall rate group. Over this 54-month period, hospitals were categorized into three groups based on long-term fall rates. Hospital-level factors differed among these three groups. This suggests that there may be hospitals in which "best practices" for fall prevention might be identified. In addition, administrators may be able

  9. A concept for multi-criteria environmental assessment of aircraft trajectories

    NARCIS (Netherlands)

    Matthes, Sigrun; Grewe, V.; Dahlmann, Katrin; Frömming, Christine; Irvine, Emma; Lim, Ling; Linke, Florian; Lührs, Benjamin; Owen, Bethan; Shine, Keith; Stromatas, Stavros; Yamashita, Hiroshi; Yin, F.

    2017-01-01

    Comprehensive assessment of the environmental aspects of flight movements is of increasing interest to the aviation sector as a potential input for developing sustainable aviation strategies that consider climate impact, air quality and noise issues simultaneously. However, comprehensive assessments

  10. Still on the Right Trajectory: State Teachers of the Year Compare Former and New State Assessments

    Science.gov (United States)

    McClellan, Catherine; Joe, Jilliam; Bassett, Katherine

    2016-01-01

    As part of state transitions to college- and career-ready (CCR) standards, including the Common Core State Standards in more than 40 states (NGA & CCSSO, 2010), states are for the first time administering new summative assessments aligned to those standards and aiming for a higher bar in assessment quality. For a majority of states, this means…

  11. 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.

  12. 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.

  13. Comparative assessment of safety indicators for vehicle trajectories on the highway

    NARCIS (Netherlands)

    Mullakkal Babu, F.A.; Wang, M.; Farah, H.; van Arem, B.; Happee, R.

    2017-01-01

    Safety measurement and analysis have been a challenging and well-researched topic in transportation. Conventionally, surrogate safety measures have been used as safety indicators in simulation models for safety assessment, in control formulations for driver assistance systems, and in data analysis

  14. Preventive Intervention: Assessing Its Effect on the Trajectories of Delinquency and Testing for Mediational Processes.

    Science.gov (United States)

    Vitaro, Frank; Brendgen, Mara; Tremblay, Richard E.

    2001-01-01

    This study assessed the impact of a prevention program on the growth of delinquency from 13 to 16 years of age and examined whether its impact operated through a chain of events compatible with many developmental models. Analysis showed that the program had an indirect effect on the growth of delinquency from 13 to 16 years of age. (Author)

  15. Key risk indicators for accident assessment conditioned on pre-crash vehicle trajectory.

    Science.gov (United States)

    Shi, X; Wong, Y D; Li, M Z F; Chai, C

    2018-08-01

    Accident events are generally unexpected and occur rarely. Pre-accident risk assessment by surrogate indicators is an effective way to identify risk levels and thus boost accident prediction. Herein, the concept of Key Risk Indicator (KRI) is proposed, which assesses risk exposures using hybrid indicators. Seven metrics are shortlisted as the basic indicators in KRI, with evaluation in terms of risk behaviour, risk avoidance, and risk margin. A typical real-world chain-collision accident and its antecedent (pre-crash) road traffic movements are retrieved from surveillance video footage, and a grid remapping method is proposed for data extraction and coordinates transformation. To investigate the feasibility of each indicator in risk assessment, a temporal-spatial case-control is designed. By comparison, Time Integrated Time-to-collision (TIT) performs better in identifying pre-accident risk conditions; while Crash Potential Index (CPI) is helpful in further picking out the severest ones (the near-accident). Based on TIT and CPI, the expressions of KRIs are developed, which enable us to evaluate risk severity with three levels, as well as the likelihood. KRI-based risk assessment also reveals predictive insights about a potential accident, including at-risk vehicles, locations and time. Furthermore, straightforward thresholds are defined flexibly in KRIs, since the impact of different threshold values is found not to be very critical. For better validation, another independent real-world accident sample is examined, and the two results are in close agreement. Hierarchical indicators such as KRIs offer new insights about pre-accident risk exposures, which is helpful for accident assessment and prediction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Flight Load Assessment for Light Aircraft Landing Trajectories in Windy Atmosphere and Near Wind Farms

    Directory of Open Access Journals (Sweden)

    Carmine Varriale

    2018-04-01

    Full Text Available This work focuses on the wake encounter problem occurring when a light, or very light, aircraft flies through or nearby a wind turbine wake. The dependency of the aircraft normal load factor on the distance from the turbine rotor in various flight and environmental conditions is quantified. For this research, a framework of software applications has been developed for generating and controlling a population of flight simulation scenarios in presence of assigned wind and turbulence fields. The JSBSim flight dynamics model makes use of several autopilot systems for simulating a realistic pilot behavior during navigation. The wind distribution, calculated with OpenFOAM, is a separate input for the dynamic model and is considered frozen during each flight simulation. The aircraft normal load factor during wake encounters is monitored at different distances from the rotor, aircraft speeds, rates of descent and crossing angles. Based on these figures, some preliminary guidelines and recommendations on safe encounter distances are provided for general aviation aircraft, with considerations on pilot comfort and flight safety. These are needed, for instance, when an accident risk assessment study is required for flight in proximity of aeolic parks. A link to the GitHub code repository is provided.

  17. 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.

  18. 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.

  19. 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.

  20. Trajectory analysis of land use and land cover maps to improve spatial-temporal patterns, and impact assessment on groundwater recharge

    Science.gov (United States)

    Zomlot, Z.; Verbeiren, B.; Huysmans, M.; Batelaan, O.

    2017-11-01

    Land use/land cover (LULC) change is a consequence of human-induced global environmental change. It is also considered one of the major factors affecting groundwater recharge. Uncertainties and inconsistencies in LULC maps are one of the difficulties that LULC timeseries analysis face and which have a significant effect on hydrological impact analysis. Therefore, an accuracy assessment approach of LULC timeseries is needed for a more reliable hydrological analysis and prediction. The objective of this paper is to assess the impact of land use uncertainty and to improve the accuracy of a timeseries of CORINE (coordination of information on the environment) land cover maps by using a new approach of identifying spatial-temporal LULC change trajectories as a pre-processing tool. This ensures consistency of model input when dealing with land-use dynamics and as such improves the accuracy of land use maps and consequently groundwater recharge estimation. As a case study the impact of consistent land use changes from 1990 until 2013 on groundwater recharge for the Flanders-Brussels region is assessed. The change trajectory analysis successfully assigned a rational trajectory to 99% of all pixels. The methodology is shown to be powerful in correcting interpretation inconsistencies and overestimation errors in CORINE land cover maps. The overall kappa (cell-by-cell map comparison) improved from 0.6 to 0.8 and from 0.2 to 0.7 for forest and pasture land use classes respectively. The study shows that the inconsistencies in the land use maps introduce uncertainty in groundwater recharge estimation in a range of 10-30%. The analysis showed that during the period of 1990-2013 the LULC changes were mainly driven by urban expansion. The results show that the resolution at which the spatial analysis is performed is important; the recharge differences using original and corrected CORINE land cover maps increase considerably with increasing spatial resolution. This study indicates

  1. 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.

  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. Developmental trajectories of infants and toddlers with good initial presentation following moderate or severe traumatic brain injury: a pilot clinical assessment project.

    Science.gov (United States)

    Pomerleau, Geneviève; Hurteau, Anne-Marie; Parent, Line; Doucet, Katrine; Corbin-Berrigan, Laurie-Ann; Gagnon, Isabelle

    2012-01-01

    The purpose of this study was to review the feasibility and usefulness of instituting a clinical protocol of scheduled assessments for children after a moderate or severe traumatic brain injury (TBI) sustained before the age of 2 years and showing no immediate deficits at hospital discharge, as well as to explore the early developmental trajectories of these children. Exploratory analytical cohort study. Pediatric Trauma Center Out-patient services. 31 children were followed within the clinical protocol of scheduled assessments. The protocol included an immediate post-injury clinical assessment of infants who sustained a TBI and follow-up assessments at the ages of 9 months, 18 months (if injured prior to that age), 30 months, and 42 months. Domains assessed at each scheduled visit included hearing, speech and language, motor performance, personal social abilities, and adaptive behaviors. Clinicians reported few difficulties with scheduling or administering the assessments, maintaining a 67% participation rate at the end of the follow-up period, thus demonstrating the feasibility of the protocol in this population. Scores on the majority of formal tests showed high variability and 15-20% of children presented with clinically significant motor and/or language delays. By 42 months of age, difficulties with adaptive behavior and personal social abilities were identified in our sample of children when compared to published norms. Qualitative clinical findings from professionals identified between 25-50% of children with potential attentional difficulties throughout the follow-up period. Findings from this study demonstrate the feasibility of implementing a clinical protocol of assessment for infants and toddlers who sustain a TBI before the age of 2 years and present with no impairments at the time of discharge from hospital. Developmental problems in this population appear to be easier to identify later in the toddler years as opposed to immediately following the TBI

  4. 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

  5. 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…

  6. 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

  7. 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.

  8. 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. .

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

    A single air molecule can have a trajectory that can be described with a line, but most meteorologists use single lines to represent the trajectories of air parcels. A single line trajectory has the disadvantage that it is a categorical description of position. Like categorized forecasts it provides no qualification, and no provision for dispersion in case the parcel contains two or more molecules which may take vastly different paths. Diffusion technology has amply demonstrated that an initial aerosol cloud or volume of gas in the atmosphere not only grows larger, but sometimes divides into puffs, each having a different path or swath. Yet, the average meteorologist, faced with the problem of predicting the future motion of a cloud, usually falls back on the line trajectory approach with the explanation that he had no better tool for long range application. In his more rational moments, he may use some arbitrary device to spread his cloud with distance. One such technique has been to separate the trajectory into two or more trajectories, spaced about the endpoint of the original trajectory after a short period of travel, repeating this every so often like a chain reaction. This has the obvious disadvantage of involving a large amount of labor without much assurance of improved accuracy. Another approach is to draw a circle about the trajectory endpoint, to represent either diffusion or error. The problem then is to know what radius to give the circle and also whether to call it diffusion or error. Meteorologists at the Nevada Test Site (NTS) are asked frequently to provide advice which involves trajectory technology, such as prediction of an aerosol cloud path, reconstruction of the motion of a volume of air, indication of the dilution, and the possible trajectory prediction error over great distances. Therefore, we set out, nearly three years ago, to provide some statistical knowledge about the status of our trajectory technology. This report contains some of the

  14. Strengthening the Assessment Trajectory: Engaging Educators in the Policy Process. Making a Measurable Difference: Case Studies from the High-Quality Assessment Project

    Science.gov (United States)

    McClellan, Catherine; Snyder, Rebecca; Woods-Murphy, Maryann; Basset, Katherine

    2018-01-01

    Great teachers recognize great assessments. As policy and education leaders work to make sure state tests are measuring the problem-solving, writing, and critical-thinking skills students need for success, they should convene and rely on teachers to review test quality and help answer the question: Do the questions on our state test reflect…

  15. 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.

  16. 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

  17. Continental-scale assessment of long-term trends in wet deposition trajectories: Role of anthropogenic and hydro-climatic drivers

    Science.gov (United States)

    Park, J.; Gall, H. E.; Niyogi, D.; Rao, S.

    2012-12-01

    The global trend of increased urbanization, and associated increased intensity of energy and material consumption and waste emissions, has contributed to shifts in the trajectories of aquatic, terrestrial, and atmospheric environments. Here, we focus on continental-scale spatiotemporal patterns in two atmospheric constituents (nitrate and sulfate), whose global biogeochemical cycles have been dramatically altered by emissions from mobile and fixed sources in urbanized and industrialized regions. The observed patterns in wet deposition fluxes of nitrate and sulfate are controlled by (1) natural hydro-climatic forcing, and (2) anthropogenic forcing (emissions and regulatory control), both of which are characterized by stochasticity and non-stationarity. We examine long-term wet deposition records in the U.S., Europe, and East Asia to evaluate how anthropogenic and natural forcing factors jointly contributed to the shifting temporal patterns of wet deposition fluxes at continental scales. These data offer clear evidence for successful implementation of regulatory controls and widespread adoption of technologies contributed to improving water quality and mitigation of adverse ecological impacts. We developed a stochastic model to project the future trajectories of wet deposition fluxes in emerging countries with fast growing urban areas. The model generates ellipses within which projected wet deposition flux trajectories are inscribed, similar to the trends in observational data. The shape of the ellipses provides information regarding the relative dominance of anthropogenic (e.g., industrial and urban emissions) versus hydro-climatic drivers (e.g., rainfall patterns, aridity index). Our analysis facilitates projections of the trajectory shift as a result of urbanization and other land-use changes, climate change, and regulatory enforcement. We use these observed data and the model to project likely trajectories for rapidly developing countries (BRIC), with a

  18. 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…

  19. 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

  20. 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.

  1. 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.

  2. IRVE-II Post-Flight Trajectory Reconstruction

    Science.gov (United States)

    O'Keefe, Stephen A.; Bose, David M.

    2010-01-01

    NASA s Inflatable Re-entry Vehicle Experiment (IRVE) II successfully demonstrated an inflatable aerodynamic decelerator after being launched aboard a sounding rocket from Wallops Flight Facility (WFF). Preliminary day of flight data compared well with pre-flight Monte Carlo analysis, and a more complete trajectory reconstruction performed with an Extended Kalman Filter (EKF) approach followed. The reconstructed trajectory and comparisons to an attitude solution provided by NASA Sounding Rocket Operations Contract (NSROC) personnel at WFF are presented. Additional comparisons are made between the reconstructed trajectory and pre and post-flight Monte Carlo trajectory predictions. Alternative observations of the trajectory are summarized which leverage flight accelerometer measurements, the pre-flight aerodynamic database, and on-board flight video. Finally, analysis of the payload separation and aeroshell deployment events are presented. The flight trajectory is reconstructed to fidelity sufficient to assess overall project objectives related to flight dynamics and overall, IRVE-II flight dynamics are in line with expectations

  3. 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

  4. 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

  5. Functional Trajectories, Cognition, and Subclinical Cerebrovascular Disease.

    Science.gov (United States)

    Dhamoon, Mandip S; Cheung, Ying-Kuen; Gutierrez, Jose; Moon, Yeseon P; Sacco, Ralph L; Elkind, Mitchell S V; Wright, Clinton B

    2018-03-01

    Cognition and education influence functional trajectories, but whether associations differ with subclinical brain infarcts (SBI) or white matter hyperintensity volume (WMHV) is unknown. We hypothesized that SBI and WMHV moderated relationships between cognitive performance and education and functional trajectories. A total of 1290 stroke-free individuals underwent brain magnetic resonance imaging and were followed for 7.3 years (mean) with annual functional assessments with the Barthel index (range, 0-100). Magnetic resonance imaging measurements included pathology-informed SBI (PI-SBI) and WMHV (% total cranial volume). Generalized estimating equation models tested associations between magnetic resonance imaging variables and baseline Barthel index and change in Barthel index, adjusting for demographic, vascular, cognitive, and social risk factors, and stroke and myocardial infarction during follow-up. We tested interactions among education level, baseline cognitive performance (Mini-Mental State score), and functional trajectories and ran models stratified by levels of magnetic resonance imaging variables. Mean age was 70.6 (SD, 9.0) years; 19% had PI-SBI, and mean WMHV was 0.68%. Education did not modify associations between cognition and functional trajectories. PI-SBI modified associations between cognition and functional trajectories ( P =0.04) with a significant protective effect of better cognition on functional decline seen only in those without PI-SBI. There was no significant interaction for WMHV ( P =0.8). PI-SBI, and greater WMHV, were associated with 2- to 3-fold steeper functional decline, holding cognition constant. PI-SBI moderated the association between cognition and functional trajectories, with 3-fold greater decline among those with PI-SBI (compared with no PI-SBI) and normal baseline cognition. This highlights the strong and independent association between subclinical markers and patient-centered trajectories over time. © 2018 American Heart

  6. 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

  7. 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.

  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. Local Politics and a Self-assessment of Political Practice. Perspective of a Neighbourhood Leader in Mexico City on their Political Trajectory

    Directory of Open Access Journals (Sweden)

    Hélène Combes

    2018-01-01

    Full Text Available This article analyses politics at the local level through the perspective of a neighbourhood leader in Mexico City. Drawing on the comprehensive sociology approach and the study of a specific career trajectory, it analyses how a neighbourhood leader works to construct beneficiaries for neighbourhood level social programs and broker resources that would not be leveraged without their work. The analysis presents an alternative vision to other analysts who have emphasized the capture of public funds for electoral purposes by neighbourhood leaders. The objective is to invite researchers to rethink the role of the local political ‘broker’ or intermediary and to consider the complexity of this role. The moral and political dilemmas that condition the behaviour of such leaders are also considered. From here, without making a moral judgement, we consider how political brokerage and the activities that it involves combine instrumental considerations with moral and ideological dimensions.

  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. 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.

  12. 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.

  13. In vivo assessment of regional mechanics post-myocardial infarction: A focus on the road ahead.

    Science.gov (United States)

    Romito, Eva; Shazly, Tarek; Spinale, Francis G

    2017-10-01

    Cardiovascular disease, particularly the occurrence of myocardial infarction (MI), remains a leading cause of morbidity and mortality (Go et al., Circulation 127: e6-e245, 2013; Go et al. Circulation 129: e28-e292, 2014). There is growing recognition that a key factor for post-MI outcomes is adverse remodeling and changes in the regional structure, composition, and mechanical properties of the MI region itself. However, in vivo assessment of regional mechanics post-MI can be confounded by the species, temporal aspects of MI healing, as well as size, location, and extent of infarction across myocardial wall. Moreover, MI regional mechanics have been assessed over varying phases of the cardiac cycle, and thus, uniform conclusions regarding the material properties of the MI region can be difficult. This review assesses past studies that have performed in vivo measures of MI mechanics and attempts to provide coalescence on key points from these studies, as well as offer potential recommendations for unifying approaches in terms of regional post-MI mechanics. A uniform approach to biophysical measures of import will allow comparisons across studies, as well as provide a basis for potential therapeutic markers.

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. 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.

  19. 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

  20. 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,

  1. 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.

  2. 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....

  3. 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...

  4. Trajectories of suicidal ideation in patients with first-episode psychosis

    DEFF Research Database (Denmark)

    Madsen, Trine; Karstoft, Karen-Inge; Secher, Rikke Gry

    2016-01-01

    BACKGROUND: Heterogeneity in suicidal ideation over time in patients with first-episode psychosis is expected, but prototypical trajectories of this have not yet been established. We aimed to identify trajectories of suicidal ideation over a 3-year period and to examine how these trajectories...... assessments in a latent growth mixture modelling analysis to empirically identify trajectories of suicidal ideation. Multivariable logistic regression analyses were applied to estimate associations between trajectories and subsequent suicidality. This trial is registered with ClinicalTrials.gov, number NCT...

  5. 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.)

  6. 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.

  7. 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 ...

  8. Is Nigeria losing its natural vegetation and landscape? Assessing the landuse-landcover change trajectories and effects in Onitsha using remote sensing and GIS

    Science.gov (United States)

    Nwaogu, Chukwudi; Okeke, Onyedikachi J.; Fadipe, Olusola O.; Bashiru, Kehinde A.; Pechanec, Vilém

    2017-12-01

    Onitsha is one of the largest commercial cities in Africa with its population growth rate increasing arithmetically for the past two decades. This situation has direct and indirect effects on the natural resources including vegetation and water. The study aimed at assessing land use-land cover (LULC) change and its effects on the vegetation and landscape from 1987 to 2015 using geoinformatics. Supervised and unsupervised classifications including maximum likelihood algorithm were performed using ENVI 4.7 and ArcGIS 10.1 versions. The LULC was classified into 7 classes: built-up areas (settlement), waterbody, thick vegetation, light vegetation, riparian vegetation, sand deposit (bare soil) and floodplain. The result revealed that all the three vegetation types decreased in areas throughout the study period while, settlement, sand deposit and floodplain areas have remarkable increase of about 100% in 2015 when compared with the total in 1987. Number of dominant plant species decreased continuously during the study. The overall classification accuracies in 1987, 2002 and 2015 was 90.7%, 92.9% and 95.5% respectively. The overall kappa coefficient of the image classification for 1987, 2002 and 2015 was 0.98, 0.93 and 0.96 respectively. In general, the average classification was above 90%, a proof that the classification was reliable and acceptable.

  9. Quantifying ataxia: ideal trajectory analysis--a technical note

    Science.gov (United States)

    McPartland, M. D.; Krebs, D. E.; Wall, C. 3rd

    2000-01-01

    We describe a quantitative method to assess repeated stair stepping stability. In both the mediolateral (ML) and anterioposterior (AP) directions, the trajectory of the subject's center of mass (COM) was compared to an ideal sinusoid. The two identified sinusoids were unique in each direction but coupled. Two dimensionless numbers-the mediolateral instability index (IML) and AP instability index (IAP)-were calculated using the COM trajectory and ideal sinusoids for each subject with larger index values resulting from less stable performance. The COM trajectories of nine nonimpaired controls and six patients diagnosed with unilateral or bilateral vestibular labyrinth hypofunction were analyzed. The average IML and IAP values of labyrinth disorder patients were respectively 127% and 119% greater than those of controls (panalysis distinguishes persons with labyrinth disorder from those without. The COM trajectories also identify movement inefficiencies attributable to vestibulopathy.

  10. Simulations of High Speed Fragment Trajectories

    Science.gov (United States)

    Yeh, Peter; Attaway, Stephen; Arunajatesan, Srinivasan; Fisher, Travis

    2017-11-01

    Flying shrapnel from an explosion are capable of traveling at supersonic speeds and distances much farther than expected due to aerodynamic interactions. Predicting the trajectories and stable tumbling modes of arbitrary shaped fragments is a fundamental problem applicable to range safety calculations, damage assessment, and military technology. Traditional approaches rely on characterizing fragment flight using a single drag coefficient, which may be inaccurate for fragments with large aspect ratios. In our work we develop a procedure to simulate trajectories of arbitrary shaped fragments with higher fidelity using high performance computing. We employ a two-step approach in which the force and moment coefficients are first computed as a function of orientation using compressible computational fluid dynamics. The force and moment data are then input into a six-degree-of-freedom rigid body dynamics solver to integrate trajectories in time. Results of these high fidelity simulations allow us to further understand the flight dynamics and tumbling modes of a single fragment. Furthermore, we use these results to determine the validity and uncertainty of inexpensive methods such as the single drag coefficient model.

  11. Trajectories of Social Anxiety during Adolescence and Relations with Cognition, Social Competence, and Temperament

    Science.gov (United States)

    Miers, A. C.; Blote, A. W.; de Rooij, M.; Bokhorst, C. L.; Westenberg, P. M.

    2013-01-01

    This cohort-sequential study examined developmental trajectories of social anxiety in a nonclinical sample (N = 331, 161 girls) aged 9 to 17 years at initial and 12 to 21 years at final assessment. We tested whether variables assessing cognition, social competence, and temperament discriminated between the trajectories. Variables were collected…

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. Puff-trajectory modelling for long-duration releases

    International Nuclear Information System (INIS)

    Underwood, B.Y.

    1988-01-01

    This investigation considers some aspects of the interpretation and application of the puff-trajectory technique which is increasingly being considered for use in accident consequence assessment. It firsthigh lights the problems of applying the straight-line Gaussian model to releases of many hours duration and the drawbacks of using the ad hoc technique of multiple straight-line plumes, thereby pointing to the advantages of allowing curved trajectories. A number of fundamental questions are asked about the conventional puff-trajectory approach such as: what is the justification for using ensemble-average spread parameters (σ values) in constructing particular realizations of the concentration field and to what sampling time should these σ values correspond. These questions are answered in the present work by returning to basics: an interpretation of the puff-trajectory method is developed which establishes a correspondence between the omission of wind-field fluctuations with period below a given value in the generation of trajectories and the achievable spatial resolution of the estimates of time-integrated concentration. In application to accident consequence assessment, this focusses attention on what spatial resolution is necessary for particular consequence types or is implicit in the computational discretization employed

  20. 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

  1. 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

  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. 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.

  4. 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...

  5. 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...

  6. Two-Year Trajectory of Fall Risk in People With Parkinson Disease: A Latent Class Analysis.

    Science.gov (United States)

    Paul, Serene S; Thackeray, Anne; Duncan, Ryan P; Cavanaugh, James T; Ellis, Theresa D; Earhart, Gammon M; Ford, Matthew P; Foreman, K Bo; Dibble, Leland E

    2016-03-01

    To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson disease (PD). Latent class analysis, specifically growth mixture modeling (GMM), of longitudinal fall risk trajectories. Assessments were conducted at 1 of 4 universities. Community-dwelling participants with PD of a longitudinal cohort study who attended at least 2 of 5 assessments over a 2-year follow-up period (N=230). Not applicable. Fall risk trajectory (low, medium, or high risk) and stability of fall risk trajectory (stable or fluctuating). Fall risk was determined at 6 monthly intervals using a simple clinical tool based on fall history, freezing of gait, and gait speed. The GMM optimally grouped participants into 3 fall risk trajectories that closely mirrored baseline fall risk status (P=.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium fall risk trajectories (Pfall risk (posterior probability fall risk trajectories over 2 years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  7. 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.

  8. 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...

  9. Changes in At-Risk American Men's Crime and Substance Use Trajectories following Fatherhood

    Science.gov (United States)

    Kerr, David C. R.; Capaldi, Deborah M.; Owen, Lee D.; Wiesner, Margit; Pears, Katherine C.

    2011-01-01

    Fatherhood can be a turning point in development and in men's crime and substance use trajectories. At-risk boys (N = 206) were assessed annually from ages 12 to 31 years. Crime, arrest, and tobacco, alcohol, and marijuana use trajectories were examined. Marriage was associated with lower levels of crime and less frequent substance use. Following…

  10. Risk and protective factors of different functional trajectories in older persons : Are these the same?

    NARCIS (Netherlands)

    Kempen, G.I.; Ranchor, A.V.; van Sonderen, E.; van Jaarsveld, C.H.; Sanderman, R.

    We examined whether risk and protective factors of different functional trajectories were the same in 1,765 Dutch older persons. We assessed disability in 1993 and reassessed it in 2001. For 2001 as compared with 1993, we distinguished three trajectory groups: substantially poorer, somewhat poorer,

  11. 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

  12. 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

  13. 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...

  14. 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.

  15. MULTI-DIMENSIONAL PATTERN DISCOVERY OF TRAJECTORIES USING CONTEXTUAL INFORMATION

    Directory of Open Access Journals (Sweden)

    M. Sharif

    2017-10-01

    Full Text Available Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

  16. Multi-Dimensional Pattern Discovery of Trajectories Using Contextual Information

    Science.gov (United States)

    Sharif, M.; Alesheikh, A. A.

    2017-10-01

    Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW) method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

  17. Context-aware pattern discovery for moving object trajectories

    Science.gov (United States)

    Sharif, Mohammad; Asghar Alesheikh, Ali; Kaffash Charandabi, Neda

    2018-05-01

    Movement of point objects are highly sensitive to the underlying situations and conditions during the movement, which are known as contexts. Analyzing movement patterns, while accounting the contextual information, helps to better understand how point objects behave in various contexts and how contexts affect their trajectories. One potential solution for discovering moving objects patterns is analyzing the similarities of their trajectories. This article, therefore, contextualizes the similarity measure of trajectories by not only their spatial footprints but also a notion of internal and external contexts. The dynamic time warping (DTW) method is employed to assess the multi-dimensional similarities of trajectories. Then, the results of similarity searches are utilized in discovering the relative movement patterns of the moving point objects. Several experiments are conducted on real datasets that were obtained from commercial airplanes and the weather information during the flights. The results yielded the robustness of DTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80 % accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.

  18. Maternal Metabolic Health Parameters During Pregnancy in Relation to Early Childhood BMI Trajectories.

    Science.gov (United States)

    Montazeri, Parisa; Vrijheid, Martine; Martinez, David; Basterrechea, Mikel; Fernandez-Somoano, Ana; Guxens, Monica; Iñiguez, Carmen; Lertxundi, Aitana; Murcia, Mario; Tardon, Adonina; Sunyer, Jordi; Valvi, Damaskini

    2018-03-01

    The objective of this study was to evaluate the associations between maternal metabolic parameters and early childhood BMI trajectories. Two thousand two hundred fifty-one children born in Spain between 2004 and 2008 were analyzed. Five BMI z score trajectories from birth to age 4 years were identified by using latent class growth analysis. Multinomial regression assessed the associations between maternal metabolic parameters and offspring's BMI trajectories. Children in the reference BMI trajectory had average size at birth followed by a slower BMI gain. Maternal prepregnancy obesity was associated with trajectories of accelerated BMI gain departing from either higher (relative risk ratio [RRR] = 1.77; 95% CI: 1.07-2.91) or lower size at birth (RRR = 1.91; 95% CI: 1.17-3.12). Gestational weight gain (GWG) above clinical guidelines was associated with a trajectory of higher birth size followed by accelerated BMI gain (RRR = 2.14; 95% CI: 1.53-2.97). Maternal serum triglycerides were negatively associated with BMI trajectories departing from lower birth sizes. Gestational diabetes, maternal serum cholesterol, and C-reactive protein were unrelated to children's BMI trajectories. Maternal prepregnancy obesity, GWG, and serum triglycerides are associated with longitudinal BMI trajectories in early childhood that may increase disease risk in later life. Health initiatives should promote healthy weight status before and during pregnancy to improve maternal and child health. © 2018 The Obesity Society.

  19. 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

  20. 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

  1. 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.

  2. ATM4E: A concept for environmentally-optimized aircraft trajectories

    NARCIS (Netherlands)

    Matthes, S; Grewe, V.; Lee, D; Linke, F.; Shine, Keith; Stromatas, Stavros

    2016-01-01

    Trajectory optimisation is one option to reduce air traffic impact on environment. A multidimensional environmental assessment framework is needed to optimize impact on climate, local air quality and noise simultaneously. An interface between flight planning and environmental impact information can

  3. 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...

  4. 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...

  5. 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...

  6. 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.

  7. Trajectories of quality of life among Chinese patients diagnosed with nasopharynegeal cancer.

    Directory of Open Access Journals (Sweden)

    Wendy W T Lam

    Full Text Available OBJECTIVE: This secondary longitudinal analysis describes distinct quality of life trajectories during eight months of radiation therapy (RT among patients with nasopharyngeal cancer (NPC and examines factors differentiating these trajectories. METHODS: 253 Chinese patients with NPC scheduled for RT were assessed at pre-treatment, and 4 months and 8 months later on QoL (Chinese version of the FACT-G, optimism, pain, eating function, and patient satisfaction. Latent growth mixture modelling identified different trajectories within each of four QoL domains: Physical, Emotional, Social/family, and Functional well-being. Multinomial logistic regression compared optimism, pain, eating function, and patient satisfaction by trajectories adjusted for demographic and medical characteristics. RESULTS: We identified three distinct trajectories for physical and emotional QoL domains, four trajectories for social/family, and two trajectories for functional domains. Within each domain most patients (physical (77%, emotional (85%, social/family (55% and functional (63% experienced relatively stable high levels of well-being over the 8-month period. Different Physical trajectory patterns were predicted by pain and optimism, whereas for Emotion-domain trajectories pain, optimism, eating enjoyment, patient satisfaction with information, and gender were predictive. Age, appetite, optimism, martial status, and household income predicted Social/family trajectories; household income, eating enjoyment, optimism, and patient satisfaction with information predicted Functional trajectories. CONCLUSION: Most patients with NPC showed high stable QoL during radiotherapy. Optimism predicted good QoL. Symptom impacts varied by QoL domain. Information satisfaction was protective in emotional and functional well-being, reflecting the importance in helping patients to establish a realistic expectation of treatment impacts.

  8. Long-term future risk of severe exacerbations: Distinct 5-year trajectories of problematic asthma.

    Science.gov (United States)

    Yii, A C A; Tan, J H Y; Lapperre, T S; Chan, A K W; Low, S Y; Ong, T H; Tan, K L; Chotirmall, S H; Sterk, P J; Koh, M S

    2017-09-01

    Assessing future risk of exacerbations is an important component of asthma management. Existing studies have investigated short- but not long-term risk. Problematic asthma patients with unfavorable long-term disease trajectory and persistently frequent severe exacerbations need to be identified early to guide treatment. To identify distinct trajectories of severe exacerbation rates among "problematic asthma" patients and develop a risk score to predict the most unfavorable trajectory. Severe exacerbation rates over five years for 177 "problematic asthma" patients presenting to a specialist asthma clinic were tracked. Distinct trajectories of severe exacerbation rates were identified using group-based trajectory modeling. Baseline predictors of trajectory were identified and used to develop a clinical risk score for predicting the most unfavorable trajectory. Three distinct trajectories were found: 58.5% had rare intermittent severe exacerbations ("infrequent"), 32.0% had frequent severe exacerbations at baseline but improved subsequently ("nonpersistently frequent"), and 9.5% exhibited persistently frequent severe exacerbations, with the highest incidence of near-fatal asthma ("persistently frequent"). A clinical risk score composed of ≥2 severe exacerbations in the past year (+2 points), history of near-fatal asthma (+1 point), body mass index ≥25kg/m 2 (+1 point), obstructive sleep apnea (+1 point), gastroesophageal reflux (+1 point), and depression (+1 point) was predictive of the "persistently frequent" trajectory (area under the receiver operating characteristic curve: 0.84, sensitivity 72.2%, specificity 81.1% using cutoff ≥3 points). The trajectories and clinical risk score had excellent performance in an independent validation cohort. Patients with problematic asthma follow distinct illness trajectories over a period of five years. We have derived and validated a clinical risk score that accurately identifies patients who will have persistently

  9. 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....

  10. 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...

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. Sensor-Based Trajectory Generation for Advanced Driver Assistance System

    Directory of Open Access Journals (Sweden)

    Christopher James Shackleton

    2013-03-01

    Full Text Available This paper investigates the trajectory generation problem for an advanced driver assistance system that could sense the driving state of the vehicle, so that a collision free trajectory can be generated safely. Specifically, the problem of trajectory generation is solved for the safety assessment of the driving state and to manipulate the vehicle in order to avoid any possible collisions. The vehicle senses the environment so as to obtain information about other vehicles and static obstacles ahead. Vehicles may share the perception of the environment via an inter-vehicle communication system. The planning algorithm is based on a visibility graph. A lateral repulsive potential is applied to adaptively maintain a trade-off between the trajectory length and vehicle clearance, which is the greatest problem associated with visibility graphs. As opposed to adaptive roadmap approaches, the algorithm exploits the structured nature of the environment for construction of the roadmap. Furthermore, the mostly organized nature of traffic systems is exploited to obtain orientation invariance, which is another limitation of both visibility graphs and adaptive roadmaps. Simulation results show that the algorithm can successfully solve the problem for a variety of commonly found scenarios.

  16. Developmental Trajectories of Male Physical Violence and Theft

    Science.gov (United States)

    Barker, Edward D.; Séguin, Jean R.; White, Helene Raskin; Bates, Marsha E.; Lacourse, Éric; Carbonneau, René; Tremblay, Richard E.

    2012-01-01

    Context Neurocognitive mechanisms have long been hypothesized to influence developmental trajectories of antisocial behavior. However, studies examining this association tend to aggregate a variety of problem behaviors that may be differently affected by neurocognitive deficits. Objective To describe the developmental trajectories of physical violence and theft from adolescence to adulthood, their associations, and the neurocognitive characteristics of individuals following different patterns of trajectory association. Design Accelerated cohort-sequential, longitudinal design. Setting Rutgers Health and Human Development Project. Participants Six hundred ninety-eight men. Main Outcome Measures Self-reports of physical violence (ages 12–24 years) and theft (ages 12–31 years) were collected across 5 waves. Neurocognitive performance was assessed with executive function and verbal IQ tests between late adolescence and early adulthood. Results The majority (55%) of subjects showed an increased frequency of theft during the study period, while only a minority (13%) evinced an increasing frequency of physical violence. Executive function and verbal IQ performance were negatively related to high frequency of physical violence but positively related to high frequency of theft. Conclusions Developmental trajectories of physical violence and theft during adolescence and early adulthood are different and differently related to neurocognitive functioning. Global indexes of antisocial behavior mask the development of antisocial behavior subtypes and putative causal mechanisms. PMID:17485611

  17. From the trajectory to the density memory

    International Nuclear Information System (INIS)

    Cakir, Rasit; Krokhin, Arkadii; Grigolini, Paolo

    2007-01-01

    In this paper we discuss the connection between trajectory and density memory. The first form of memory is a property of a stochastic trajectory, whose stationary correlation function shows that the fluctuation at a given time depends on the earlier fluctuations. The density memory is a property of a collection of trajectories, whose density time evolution is described by a time convoluted equation showing that the density time evolution depends on its past history. We show that the trajectory memory does not necessarily yields density memory, and that density memory might be compatible with the existence of abrupt jumps resetting to zero the system's memory. We focus our attention on a time-convoluted diffusion equation, when the memory kernel is an inverse power law with (i) negative and (ii) positive tail. In case (i) there exist both renewal trajectories and trajectories with memory, compatible with this equation. Case (ii), which has eluded so far a convincing interpretation in terms of trajectories, is shown to be compatible only with trajectory memory

  18. User oriented trajectory search for trip recommendation

    KAUST Repository

    Shang, Shuo; Ding, Ruogu; Yuan, Bo; Xie, Kexin; Zheng, Kai; Kalnis, Panos

    2012-01-01

    trajectory search by locations (spatial domain only), we consider both spatial and textual domains in the new UOTS query. Given a trajectory data set, the query input contains a set of intended places given by the traveler and a set of textual attributes

  19. Soccer Ball Lift Coefficients via Trajectory Analysis

    Science.gov (United States)

    Goff, John Eric; Carre, Matt J.

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

  20. Complex trajectories in a classical periodic potential

    International Nuclear Information System (INIS)

    Anderson, Alexander G; Bender, Carl M

    2012-01-01

    This paper examines the complex trajectories of a classical particle in the potential V(x) = −cos (x). Almost all the trajectories describe a particle that hops from one well to another in an erratic fashion. However, it is shown analytically that there are two special classes of trajectories x(t) determined only by the energy of the particle and not by the initial position of the particle. The first class consists of periodic trajectories; that is, trajectories that return to their initial position x(0) after some real time T. The second class consists of trajectories for which there exists a real time T such that x(t + T) = x(t) ± 2π. These two classes of classical trajectories are analogous to valence and conduction bands in quantum mechanics, where the quantum particle either remains localized or else tunnels resonantly (conducts) through a crystal lattice. These two special types of trajectories are associated with sets of energies of measure 0. For other energies, it is shown that for long times the average velocity of the particle becomes a fractal-like function of energy. (paper)

  1. Complex trajectories in a classical periodic potential

    Science.gov (United States)

    Anderson, Alexander G.; Bender, Carl M.

    2012-11-01

    This paper examines the complex trajectories of a classical particle in the potential V(x) = -cos (x). Almost all the trajectories describe a particle that hops from one well to another in an erratic fashion. However, it is shown analytically that there are two special classes of trajectories x(t) determined only by the energy of the particle and not by the initial position of the particle. The first class consists of periodic trajectories; that is, trajectories that return to their initial position x(0) after some real time T. The second class consists of trajectories for which there exists a real time T such that x(t + T) = x(t) ± 2π. These two classes of classical trajectories are analogous to valence and conduction bands in quantum mechanics, where the quantum particle either remains localized or else tunnels resonantly (conducts) through a crystal lattice. These two special types of trajectories are associated with sets of energies of measure 0. For other energies, it is shown that for long times the average velocity of the particle becomes a fractal-like function of energy.

  2. Multi Sector Planning Tools for Trajectory-Based Operations

    Science.gov (United States)

    Prevot, Thomas; Mainini, Matthew; Brasil, Connie

    2010-01-01

    This paper discusses a suite of multi sector planning tools for trajectory-based operations that were developed and evaluated in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center. The toolset included tools for traffic load and complexity assessment as well as trajectory planning and coordination. The situation assessment tools included an integrated suite of interactive traffic displays, load tables, load graphs, and dynamic aircraft filters. The planning toolset allowed for single and multi aircraft trajectory planning and data communication-based coordination of trajectories between operators. Also newly introduced was a real-time computation of sector complexity into the toolset that operators could use in lieu of aircraft count to better estimate and manage sector workload, especially in situations with convective weather. The tools were used during a joint NASA/FAA multi sector planner simulation in the AOL in 2009 that had multiple objectives with the assessment of the effectiveness of the tools being one of them. Current air traffic control operators who were experienced as area supervisors and traffic management coordinators used the tools throughout the simulation and provided their usefulness and usability ratings in post simulation questionnaires. This paper presents these subjective assessments as well as the actual usage data that was collected during the simulation. The toolset was rated very useful and usable overall. Many elements received high scores by the operators and were used frequently and successfully. Other functions were not used at all, but various requests for new functions and capabilities were received that could be added to the toolset.

  3. The power of a single trajectory

    Science.gov (United States)

    Schnellbächer, Nikolas D.; Schwarz, Ulrich S.

    2018-03-01

    Random walks are often evaluated in terms of their mean squared displacements, either for a large number of trajectories or for one very long trajectory. An alternative evaluation is based on the power spectral density, but here it is less clear which information can be extracted from a single trajectory. For continuous-time Brownian motion, Krapf et al now have mathematically proven that the one property that can be reliably extracted from a single trajectory is the frequency dependence of the ensemble-averaged power spectral density (Krapf et al 2018 New J. Phys. 20 023029). Their mathematical analysis also identifies the appropriate frequency window for this procedure and shows that the diffusion coefficient can be extracted by averaging over a small number of trajectories. The authors have verified their analytical results both by computer simulations and experiments.

  4. 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.

  5. 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.

  6. 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...

  7. Examining the Weight Trajectory of College Students.

    Science.gov (United States)

    Pope, Lizzy; Hansen, Danielle; Harvey, Jean

    2017-02-01

    To examine the weight trajectory of students over 4 years of college. Anthropometric assessments were completed at the beginning and end of students' freshman year and the end of senior year to calculate body mass index. Questionnaires assessing weight-related behaviors were completed in senior year. Of the original 117 students, 86 remained in the study for 4 years. Body mass index was significantly higher at the end of senior year (mean, 24.84; SD, 4.46) vs the beginning of freshman year (mean, 23.59; SD, 4.01; t[85] = 5.61; P Students' mean weight gain was 4.38 kg and the sample increased from 23% to 41% overweight/obese. No significant associations were found between BMI and lifestyle factors. This study suggests that students gain weight throughout college, which highlights the need for weight control interventions to target more than just freshman college students. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  8. Task Decomposition Module For Telerobot Trajectory Generation

    Science.gov (United States)

    Wavering, Albert J.; Lumia, Ron

    1988-10-01

    A major consideration in the design of trajectory generation software for a Flight Telerobotic Servicer (FTS) is that the FTS will be called upon to perform tasks which require a diverse range of manipulator behaviors and capabilities. In a hierarchical control system where tasks are decomposed into simpler and simpler subtasks, the task decomposition module which performs trajectory planning and execution should therefore be able to accommodate a wide range of algorithms. In some cases, it will be desirable to plan a trajectory for an entire motion before manipulator motion commences, as when optimizing over the entire trajectory. Many FTS motions, however, will be highly sensory-interactive, such as moving to attain a desired position relative to a non-stationary object whose position is periodically updated by a vision system. In this case, the time-varying nature of the trajectory may be handled either by frequent replanning using updated sensor information, or by using an algorithm which creates a less specific state-dependent plan that determines the manipulator path as the trajectory is executed (rather than a priori). This paper discusses a number of trajectory generation techniques from these categories and how they may be implemented in a task decompo-sition module of a hierarchical control system. The structure, function, and interfaces of the proposed trajectory gener-ation module are briefly described, followed by several examples of how different algorithms may be performed by the module. The proposed task decomposition module provides a logical structure for trajectory planning and execution, and supports a large number of published trajectory generation techniques.

  9. 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.

  10. MGA trajectory planning with an ACO-inspired algorithm

    Science.gov (United States)

    Ceriotti, Matteo; Vasile, Massimiliano

    2010-11-01

    Given a set of celestial bodies, the problem of finding an optimal sequence of swing-bys, deep space manoeuvres (DSM) and transfer arcs connecting the elements of the set is combinatorial in nature. The number of possible paths grows exponentially with the number of celestial bodies. Therefore, the design of an optimal multiple gravity assist (MGA) trajectory is a NP-hard mixed combinatorial-continuous problem. Its automated solution would greatly improve the design of future space missions, allowing the assessment of a large number of alternative mission options in a short time. This work proposes to formulate the complete automated design of a multiple gravity assist trajectory as an autonomous planning and scheduling problem. The resulting scheduled plan will provide the optimal planetary sequence and a good estimation of the set of associated optimal trajectories. The trajectory model consists of a sequence of celestial bodies connected by two-dimensional transfer arcs containing one DSM. For each transfer arc, the position of the planet and the spacecraft, at the time of arrival, are matched by varying the pericentre of the preceding swing-by, or the magnitude of the launch excess velocity, for the first arc. For each departure date, this model generates a full tree of possible transfers from the departure to the destination planet. Each leaf of the tree represents a planetary encounter and a possible way to reach that planet. An algorithm inspired by ant colony optimization (ACO) is devised to explore the space of possible plans. The ants explore the tree from departure to destination adding one node at the time: every time an ant is at a node, a probability function is used to select a feasible direction. This approach to automatic trajectory planning is applied to the design of optimal transfers to Saturn and among the Galilean moons of Jupiter. Solutions are compared to those found through more traditional genetic-algorithm techniques.

  11. Developmental trajectories in primary schoolchildren using n-back task

    Directory of Open Access Journals (Sweden)

    Mónica eLópez-Vicente

    2016-05-01

    Full Text Available Background: Neuropsychological instruments to assess cognitive trajectories during childhood in epidemiological studies are needed. This would improve neurodevelopment characterization in order to identify its potential determinants. We aimed to study whether repeated measures of n-back, a working memory task, detect developmental trajectories in schoolchildren during a one-year follow-up.Methods: We administered the n-back task to 2,897 healthy children aged 7-11 years old from 39 schools in Barcelona (Spain. The task consisted of 2 levels of complexity or loads (2- and 3-back and 2 different stimuli (numbers and words. Participants performed the task four times from January 2012 to March 2013. To study the trajectories during the follow-up, we performed linear mixed-effects models including school, individual and age as random effects.Results: We observed improvements related to age in n-back outcomes d’, HRT and accuracy, as well as reduced cognitive growth at older ages in d’ and HRT. Greater improvements in performance were observed at younger ages, in 2-back, in verbal rather than numerical stimuli and in girls compared to boys. Boys responded faster at baseline, while girls showed increased growth in 2-back numbers. Children with ADHD (Attention Deficit and Hyperactivity Disorder symptoms (15% of boys and 6% of girls had a lower working memory at baseline, but they showed similar cognitive growth trajectories in numbers variants of the task, as compared to children without ADHD symptoms. However, the age-related improvement in response speed was not observed in children with ADHD symptoms. Conclusions: Changes in n-back outcomes reflected developmental trajectories in one-year follow-up. The present results suggest that the repeated administration of this task can be used to study the factors that may alter the cognitive development during childhood.

  12. Tracers vs. trajectories in a coastal region

    Science.gov (United States)

    Engqvist, A.; Döös, K.

    2008-12-01

    Two different methods of estimating the water exchange through a Baltic coastal region have been used, consisting of particle trajectories and passive tracers. Water is traced from and to a small discharge region near the coast. The discharge material in this region is treated as zero dimensional particles or tracers with neutral buoyancy. The real discharge material could be a leakage of radio-nuclides through the sea floor from an underground repository of nuclear waste. Water exchange rates between the discharge region and the model domain are estimated using both forward and backward trajectories as well as passive tracers. The Lagrangian trajectories can account for the time evolution of the water exchange while the tracers give one average age per model grid box. Water exchange times such as residence time, age and transient times have been calculated with trajectories but only the average age (AvA) for tracers. The trajectory calculations provide a more detailed time evolution than the tracers. On the other hand the tracers are integrated "on-line" simultaneously in the sea circulation model with the same time step while the Lagrangian trajectories are integrated "off-line" from the stored model velocities with its inherent temporal resolution, presently one hour. The sub-grid turbulence is parameterised as a Laplacian diffusion for the passive tracers and with an extra stochastic velocity for trajectories. The importance of the parameterised sub-grid turbulence for the trajectories is estimated to give an extra diffusion of the same order as the Laplacian diffusion by comparing the Lagrangian dispersions with and without parameterisation. The results of the different methods are similar but depend on the chosen diffusivity coefficient with a slightly higher correlation between trajectories and tracers when integrated with a lower diffusivity coefficient.

  13. Path integrals and geometry of trajectories

    International Nuclear Information System (INIS)

    Blau, M.; Keski-Vakkuri, E.; Niemi, A.J.

    1990-01-01

    A geometrical interpretation of path integrals is developed in the space of trajectories. This yields a supersymmetric formulation of a generic path integral, with the supersymmetry resembling the BRST supersymmetry of a first class constrained system. If the classical equation of motion is a Killing vector field in the space of trajectories, the supersymmetry localizes the path integral to classical trajectories and the WKB approximation becomes exact. This can be viewed as a path integral generalization of the Duistermaat-Heckman theorem, which states the conditions for the exactness of the WKB approximation for integrals in a compact phase space. (orig.)

  14. An Examination of "The Martian" Trajectory

    Science.gov (United States)

    Burke, Laura

    2015-01-01

    This analysis was performed to support a request to examine the trajectory of the Hermes vehicle in the novel "The Martian" by Andy Weir. Weir developed his own tool to perform the analysis necessary to provide proper trajectory information for the novel. The Hermes vehicle is the interplanetary spacecraft that shuttles the crew to and from Mars. It is notionally a Nuclear powered vehicle utilizing VASIMR engines for propulsion. The intent of this analysis was the determine whether the trajectory as it was outlined in the novel is consistent with the rules of orbital mechanics.

  15. Soccer ball lift coefficients via trajectory analysis

    International Nuclear Information System (INIS)

    Goff, John Eric; Carre, Matt J

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  16. Soccer ball lift coefficients via trajectory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goff, John Eric [Department of Physics, Lynchburg College, Lynchburg, VA 24501 (United States); Carre, Matt J, E-mail: goff@lynchburg.ed [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2010-07-15

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  17. Helicopter trajectory planning using optimal control theory

    Science.gov (United States)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1988-01-01

    A methodology for optimal trajectory planning, useful in the nap-of-the-earth guidance of helicopters, is presented. This approach uses an adjoint-control transformation along with a one-dimensional search scheme for generating the optimal trajectories. In addition to being useful for helicopter nap-of-the-earth guidance, the trajectory planning solution is of interest in several other contexts, such as robotic vehicle guidance and terrain-following guidance for cruise missiles and aircraft. A distinguishing feature of the present research is that the terrain constraint and the threat envelopes are incorporated in the equations of motion. Second-order necessary conditions are examined.

  18. Student-teacher relationship trajectories and mental health problems in young children

    OpenAIRE

    Miller-Lewis, Lauren R; Sawyer, Alyssa CP; Searle, Amelia K; Mittinty, Murthy N; Sawyer, Michael G; Lynch, John W

    2014-01-01

    Background This longitudinal study classified groups of children experiencing different trajectories of student-teacher relationship quality over the transition from preschool into school, and determined the strength of the association between different student-teacher relationship trajectories and childhood mental health problems in the second year of primary school. Methods A community sample of 460 Australian children were assessed in preschool (age 4), the first school year (age 5), and s...

  19. CONTROL OF AIRCRAFT TRAJECTORIES IN THE CONDITIONS OF THE NAVIGATION SESSION OPTIMIZATION AT AUTOMATIC DEPENDENT SURVEILLANCE

    Directory of Open Access Journals (Sweden)

    V. V. Erokhin

    2015-01-01

    Full Text Available Algorithms of determination of coordinates of the aircraft in the integrated system of navigation and optimum control of a trajectory are considered. Results of researches of parameters of a navigation session and precision characteristics of an assessment of location showed that application of optimum control of a trajectory allowув to increase the accuracy of navigation definitions in case of incomplete constellation of navigation satellites.

  20. Trajectories of posttraumatic stress symptoms (PTSS) after major war among Palestinian children: Trauma, family- and child-related predictors.

    Science.gov (United States)

    Punamäki, Raija-Leena; Palosaari, Esa; Diab, Marwan; Peltonen, Kirsi; Qouta, Samir R

    2015-02-01

    Research shows great individual variation in changes in posttraumatic stress symptoms (PTSSs) after major traumas of terrorist attacks, military combat, and natural disasters. Earlier studies have identified specific mental health trajectories both in children and adults. This study aimed, first, to identify potential PTSS-related trajectories by using latent class growth analyses among children in a three-wave assessment after the 2008/2009 War on Gaza, Palestine. Second, it analyzed how family- and child related factors (e.g., attachment relations, posttraumatic cognitions (PTCs), guilt, and emotion regulation) associate with the trajectory class membership. The sample consisted of 240 Palestinian children (49.4% girls and 50.6% boys) of 10-13 years of age (M=11.29, SD=0.68), who completed PTSS (CRIES) assessments at 3 (T1), 5 (T2), and 11 (T3) months after the war. Children reported their personal exposure to war trauma, attachment style, cognitive trauma processing, and emotion regulation, and their parents reported family war trauma exposure and attachment style. Results revealed a three-trajectory solution, a majority of children belonging to the Recovery trajectory (n=183), and a minority belonged either to Resistant trajectory (n=29) or to Increasing symptoms trajectory (n=28). Low levels of negative posttraumatic cognitive appraisals, feelings of guilt and emotion regulation were characteristic of children in the Resistant trajectory as compared to Increasing symptoms trajectory. Father׳s attachment security was further associated with the Resistant trajectory membership. Children׳s attachment avoidance and high parental trauma were typical to children in Recovery trajectory (as compared to the Increasing symptoms trajectory). Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Active Transportation Demand Management (ATDM) Trajectory Level Validation

    Data.gov (United States)

    Department of Transportation — The ATDM Trajectory Validation project developed a validation framework and a trajectory computational engine to compare and validate simulated and observed vehicle...

  2. Low Thrust Trajectory Design for GSFC Missions Project

    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...

  3. Assessment of Myocardial Remodeling Using an Elastin/Tropoelastin Specific Agent with High Field Magnetic Resonance Imaging (MRI).

    Science.gov (United States)

    Protti, Andrea; Lavin, Begoña; Dong, Xuebin; Lorrio, Silvia; Robinson, Simon; Onthank, David; Shah, Ajay M; Botnar, Rene M

    2015-08-13

    Well-defined inflammation, proliferation, and maturation phases orchestrate the remodeling of the injured myocardium after myocardial infarction (MI) by controlling the formation of new extracellular matrix. The extracellular matrix consists mainly of collagen but also fractions of elastin. It is thought that elastin is responsible for maintaining elastic properties of the myocardium, thus reducing the risk of premature rupture. An elastin/tropoelastin-specific contrast agent (Gd-ESMA) was used to image tropoelastin and mature elastin fibers for in vivo assessment of extracellular matrix remodeling post-MI. Gd-ESMA enhancement was studied in a mouse model of myocardial infarction using a 7 T MRI scanner and results were compared to those achieved after injection of a nonspecific control contrast agent, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In the infarcted tissue, Gd-ESMA uptake (measured as R1 relaxation rate) steadily increased from day 3 to day 21 as a result of the synthesis of elastin/tropoelastin. R1 values were in good agreement with histological findings. A similar R1 behavior was observed in the remote myocardium. No mature cross-linked elastin was found at any time point. In contrast, Gd-DTPA uptake was only observed in the infarct with no changes in R1 values between 3 and 21 days post-MI. We demonstrate the feasibility of in vivo imaging of extracellular matrix remodeling post-MI using a tropoelastin/elastin binding MR contrast agent, Gd-ESMA. We found that tropoelastin is the main contributor to the increased MRI signal at late stages of MI where its augmentation in areas of infarction was in good agreement with the R1 increase. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  4. Entropic Movement Complexity Reflects Subjective Creativity Rankings of Visualized Hand Motion Trajectories

    Science.gov (United States)

    Peng, Zhen; Braun, Daniel A.

    2015-01-01

    In a previous study we have shown that human motion trajectories can be characterized by translating continuous trajectories into symbol sequences with well-defined complexity measures. Here we test the hypothesis that the motion complexity individuals generate in their movements might be correlated to the degree of creativity assigned by a human observer to the visualized motion trajectories. We asked participants to generate 55 novel hand movement patterns in virtual reality, where each pattern had to be repeated 10 times in a row to ensure reproducibility. This allowed us to estimate a probability distribution over trajectories for each pattern. We assessed motion complexity not only by the previously proposed complexity measures on symbolic sequences, but we also propose two novel complexity measures that can be directly applied to the distributions over trajectories based on the frameworks of Gaussian Processes and Probabilistic Movement Primitives. In contrast to previous studies, these new methods allow computing complexities of individual motion patterns from very few sample trajectories. We compared the different complexity measures to how a group of independent jurors rank ordered the recorded motion trajectories according to their personal creativity judgment. We found three entropic complexity measures that correlate significantly with human creativity judgment and discuss differences between the measures. We also test whether these complexity measures correlate with individual creativity in divergent thinking tasks, but do not find any consistent correlation. Our results suggest that entropic complexity measures of hand motion may reveal domain-specific individual differences in kinesthetic creativity. PMID:26733896

  5. Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

    Science.gov (United States)

    Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

    2014-01-01

    Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P = 0.0002) and a 43% reduction in total mortality (P = 0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

  6. Leveraging Chaos in Continuous Thrust Trajectory Design

    Data.gov (United States)

    National Aeronautics and Space Administration — A trajectory design tool is sought to leverage chaos and nonlinear dynamics present in multi-body gravitational fields to design ultra-low energy transfer...

  7. Age trajectories of stroke case fatality

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  8. Highly Accurate Measurement of Projectile Trajectories

    National Research Council Canada - National Science Library

    Leathem, J

    1997-01-01

    .... The method has been extensively used for free flight testing of weapon models. This report describes the on board instrumentation, the range instrumentation and the experimental procedure used to carry out the trajectory measurements...

  9. Analytical Ballistic Trajectories with Approximately Linear Drag

    Directory of Open Access Journals (Sweden)

    Giliam J. P. de Carpentier

    2014-01-01

    Full Text Available This paper introduces a practical analytical approximation of projectile trajectories in 2D and 3D roughly based on a linear drag model and explores a variety of different planning algorithms for these trajectories. Although the trajectories are only approximate, they still capture many of the characteristics of a real projectile in free fall under the influence of an invariant wind, gravitational pull, and terminal velocity, while the required math for these trajectories and planners is still simple enough to efficiently run on almost all modern hardware devices. Together, these properties make the proposed approach particularly useful for real-time applications where accuracy and performance need to be carefully balanced, such as in computer games.

  10. Trajectory Clustering with Applications to Airspace Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a framework aimed at monitoring the behavior of aircraft in a given airspace. Trajectories that constitute typical operations are determined and...

  11. Trajectory behaviour at different phonemic context sizes

    CSIR Research Space (South Africa)

    Badenhorst, J

    2011-11-01

    Full Text Available The authors propose a piecewise-linear model for the temporal trajectories of Mel Frequency Cepstral Coefficients during phone transitions. As with conventional Hidden Markov Models, the parameters of the model can be estimated for different...

  12. Trajectory tracking control for underactuated stratospheric airship

    Science.gov (United States)

    Zheng, Zewei; Huo, Wei; Wu, Zhe

    2012-10-01

    Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

  13. The existence of trajectories joining critical points

    International Nuclear Information System (INIS)

    Yu Shuxiang.

    1985-01-01

    In this paper, using the notion of an isolating block and the concept of canonical regions, three existence criteria of trajectories connecting a pair of critical points of planar differential equations are given. (author)

  14. 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)

  15. Trajectory averaging for stochastic approximation MCMC algorithms

    KAUST Repository

    Liang, Faming

    2010-01-01

    to the stochastic approximation Monte Carlo algorithm [Liang, Liu and Carroll J. Amer. Statist. Assoc. 102 (2007) 305-320]. The application of the trajectory averaging estimator to other stochastic approximationMCMC algorithms, for example, a stochastic

  16. Quantum dynamics modeled by interacting trajectories

    Science.gov (United States)

    Cruz-Rodríguez, L.; Uranga-Piña, L.; Martínez-Mesa, A.; Meier, C.

    2018-03-01

    We present quantum dynamical simulations based on the propagation of interacting trajectories where the effect of the quantum potential is mimicked by effective pseudo-particle interactions. The method is applied to several quantum systems, both for bound and scattering problems. For the bound systems, the quantum ground state density and zero point energy are shown to be perfectly obtained by the interacting trajectories. In the case of time-dependent quantum scattering, the Eckart barrier and uphill ramp are considered, with transmission coefficients in very good agreement with standard quantum calculations. Finally, we show that via wave function synthesis along the trajectories, correlation functions and energy spectra can be obtained based on the dynamics of interacting trajectories.

  17. Action Recognition Using Discriminative Structured Trajectory Groups

    KAUST Repository

    Atmosukarto, Indriyati

    2015-01-06

    In this paper, we develop a novel framework for action recognition in videos. The framework is based on automatically learning the discriminative trajectory groups that are relevant to an action. Different from previous approaches, our method does not require complex computation for graph matching or complex latent models to localize the parts. We model a video as a structured bag of trajectory groups with latent class variables. We model action recognition problem in a weakly supervised setting and learn discriminative trajectory groups by employing multiple instance learning (MIL) based Support Vector Machine (SVM) using pre-computed kernels. The kernels depend on the spatio-temporal relationship between the extracted trajectory groups and their associated features. We demonstrate both quantitatively and qualitatively that the classification performance of our proposed method is superior to baselines and several state-of-the-art approaches on three challenging standard benchmark datasets.

  18. 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...

  19. DIRECTIONAL WELL TRAJECTORY DESIGN: THE THEORITICAL ...

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... record presentation of a desired complex directional well trajectory, also from which the overall angle change. (dogleg) is observed not to ... example; 23oNE means 23 degrees East from North, .... Azimuth Angles Selection.

  20. 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.

  1. 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.

  2. User Oriented Trajectory Search for Trip Recommendation

    KAUST Repository

    Ding, Ruogu

    2012-07-08

    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 Oriented Trajectory Search (UOTS) query processing. In contrast to conventional trajectory search by locations (spatial domain only), we consider both spatial and textual domains in the new UOTS query. Given a trajectory data set, the query input contains a set of intended places given by the traveler and a set of textual attributes describing the traveler’s preference. If a trajectory is connecting/close to the specified query locations, and the textual attributes of the trajectory are similar to the traveler’s preference, it will be recommended to the traveler. This type of queries can enable many popular applications such as trip planning and recommendation. There are two challenges in UOTS query processing, (i) how to constrain the searching range in two domains and (ii) how to schedule multiple query sources effectively. To overcome the challenges and answer the UOTS query efficiently, a novel collaborative searching approach is developed. Conceptually, the UOTS query processing is conducted in the spatial and textual domains alternately. A pair of upper and lower bounds are devised to constrain the searching range in two domains. In the meantime, a heuristic searching strategy based on priority ranking is adopted for scheduling the multiple query sources, which can further reduce the searching range and enhance the query efficiency notably. Furthermore, the devised collaborative searching approach can be extended to situations where the query locations are ordered. Extensive experiments are conducted on both real and synthetic trajectory data in road networks. Our approach is verified to be effective in reducing both CPU time and disk I/O time.

  3. Mobility Modelling through Trajectory Decomposition and Prediction

    OpenAIRE

    Faghihi, Farbod

    2017-01-01

    The ubiquity of mobile devices with positioning sensors make it possible to derive user's location at any time. However, constantly sensing the position in order to track the user's movement is not feasible, either due to the unavailability of sensors, or computational and storage burdens. In this thesis, we present and evaluate a novel approach for efficiently tracking user's movement trajectories using decomposition and prediction of trajectories. We facilitate tracking by taking advantage ...

  4. 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.

  5. Trajectories of Nutritional Status and Cognitive Impairment among Older Taiwanese with Hip Fracture.

    Science.gov (United States)

    Wang, H P; Liang, J; Kuo, L M; Chen, C Y; Shyu, Y I L

    2017-01-01

    This paper describes the trajectories of nutritional status and cognitive impairment and their correlation among older Taiwanese over 1 year after hip-fracture surgery. Secondary analysis of data from a clinical trial evaluating the effects of three types of post-discharge care for 292 older hip-fracture patients (age >60 years). Nutritional status was assessed by the Mini Nutritional Assessment before and 1, 3, 6, 12 months after hospital discharge. Cognitive function was measured by the Mini-Mental State Examination before surgery, at hospital discharge, 6 and 12 months after discharge. Trajectories of nutritional status and cognitive impairment were depicted by latent class growth modeling, whereas linkages between nutritional-status and cognitive-impairment trajectories were assessed by multinomial logistic regression. Nutritional status in general improved significantly, particularly during the first 3 months after discharge. We identified three trajectories of nutritional status: malnourished (15.4%), at risk for malnutrition (38.9%), and well-nourished (45.7%). In contrast, cognitive changes followed four largely linear but distinct trajectories: moderately impaired (12.2%), mildly impaired (27.8%), borderline impaired (21.8%), and cognitively intact (38.2%). Trajectories of nutritional status were significantly associated with cognitive-function trajectories. For instance, relative to malnourished patients, well-nourished patients were 95% less likely (OR=0.05, CI =0.01-0.24) to be moderately cognitively impaired. A good nutritional-status trajectory after hip fracture was associated with better cognitive function. To treat and care for elderly hip-fractured patients, specific interventions need to target those who are malnourished or at risk of malnutrition to decrease their risk for cognitive impairment.

  6. Identifying Trajectories of Borderline Personality Features in Adolescence: Antecedent and Interactive Risk Factors.

    Science.gov (United States)

    Haltigan, John D; Vaillancourt, Tracy

    2016-03-01

    To examine trajectories of adolescent borderline personality (BP) features in a normative-risk cohort (n = 566) of Canadian children assessed at ages 13, 14, 15, and 16 and childhood predictors of trajectory group membership assessed at ages 8, 10, 11, and 12. Data were drawn from the McMaster Teen Study, an on-going study examining relations among bullying, mental health, and academic achievement. Participants and their parents completed a battery of mental health and peer relations questionnaires at each wave of the study. Academic competence was assessed at age 8 (Grade 3). Latent class growth analysis, analysis of variance, and logistic regression were used to analyze the data. Three distinct BP features trajectory groups were identified: elevated or rising, intermediate or stable, and low or stable. Parent- and child-reported mental health symptoms, peer relations risk factors, and intra-individual risk factors were significant predictors of elevated or rising and intermediate or stable trajectory groups. Child-reported attention-deficit hyperactivity disorder (ADHD) and somatization symptoms uniquely predicted elevated or rising trajectory group membership, whereas parent-reported anxiety and child-reported ADHD symptoms uniquely predicted intermediate or stable trajectory group membership. Child-reported somatization symptoms was the only predictor to differentiate the intermediate or stable and elevated or rising trajectory groups (OR 1.15, 95% CI 1.04 to 1.28). Associations between child-reported reactive temperament and elevated BP features trajectory group membership were 10.23 times higher among children who were bullied, supporting a diathesis-stress pathway in the development of BP features for these youth. Findings demonstrate the heterogeneous course of BP features in early adolescence and shed light on the potential prodromal course of later borderline personality disorder. © The Author(s) 2015.

  7. 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.

  8. 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.

  9. 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.

  10. UAV Trajectory Modeling Using Neural Networks

    Science.gov (United States)

    Xue, Min

    2017-01-01

    Massive small unmanned aerial vehicles are envisioned to operate in the near future. While there are lots of research problems need to be addressed before dense operations can happen, trajectory modeling remains as one of the keys to understand and develop policies, regulations, and requirements for safe and efficient unmanned aerial vehicle operations. The fidelity requirement of a small unmanned vehicle trajectory model is high because these vehicles are sensitive to winds due to their small size and low operational altitude. Both vehicle control systems and dynamic models are needed for trajectory modeling, which makes the modeling a great challenge, especially considering the fact that manufactures are not willing to share their control systems. This work proposed to use a neural network approach for modelling small unmanned vehicle's trajectory without knowing its control system and bypassing exhaustive efforts for aerodynamic parameter identification. As a proof of concept, instead of collecting data from flight tests, this work used the trajectory data generated by a mathematical vehicle model for training and testing the neural network. The results showed great promise because the trained neural network can predict 4D trajectories accurately, and prediction errors were less than 2:0 meters in both temporal and spatial dimensions.

  11. Two-year trajectory of fall risk in people with Parkinson’s disease: a latent class analysis

    Science.gov (United States)

    Paul, Serene S; Thackeray, Anne; Duncan, Ryan P; Cavanaugh, James T; Ellis, Theresa D; Earhart, Gammon M; Ford, Matthew P; Foreman, K Bo; Dibble, Leland E

    2015-01-01

    Objective To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson’s disease (PD). Design Latent class analysis, specifically growth mixture modeling (GMM) of longitudinal fall risk trajectories. Setting Not applicable. Participants 230 community-dwelling PD participants of a longitudinal cohort study who attended at least two of five assessments over a two year period. Interventions Not applicable. Main Outcome Measures Fall risk trajectory (low, medium or high risk) and stability of fall risk trajectory (stable or fluctuating). Fall risk was determined at 6-monthly intervals using a simple clinical tool based on fall history, freezing of gait, and gait speed. Results The GMM optimally grouped participants into three fall risk trajectories that closely mirrored baseline fall risk status (p=.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium risk trajectories (pfall risk (posterior probability fall risk trajectories over two years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD. PMID:26606871

  12. Multivariate trajectories across multiple domains of health-related quality of life in children with new-onset epilepsy.

    Science.gov (United States)

    Sajobi, Tolulope T; Wang, Meng; Ferro, Mark A; Brobbey, Anita; Goodwin, Shane; Speechley, Kathy N; Wiebe, Samuel

    2017-10-01

    The diagnosis of epilepsy in children is known to impact the trajectory of their health-related quality of life (HRQOL) over time. However, there is limited knowledge about variations in longitudinal trajectories across multiple domains of HRQOL. This study aims to characterize the heterogeneity in HRQOL trajectories across multiple HRQOL domains and to evaluate predictors of differences among the identified trajectory groups in children with new-onset epilepsy. Data were obtained from the Health Related Quality of Life in Children with Epilepsy Study (HERQULES), a prospective multi-center study of 373 children newly diagnosed with new-onset epilepsy who were followed up over 2years. Child HRQOL and family factors were reported by parents, and clinical characteristics were reported by neurologists. Group-based multi-trajectory modeling was adopted to characterize longitudinal trajectories of HRQOL as measured by the individual domains of cognitive, emotional, physical, and social functioning in the 55-item Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55). Multinomial logistic regression was used to assess potential factors that explain differences among the identified latent trajectory groups. Three distinct HRQOL trajectory subgroups were identified in children with new-onset epilepsy based on HRQOL scores: "High" (44.7%), "Intermediate" (37.0%), and "Low" (18.3%). While most trajectory groups exhibited increasing scores over time on physical and social domains, both flat and declining trajectories were noted on emotional and cognitive domains. Less severe epilepsy, an absence of cognitive and behavioral problems, lower parental depression scores, better family functioning, and fewer family demands were associated with a "Higher" or "Intermediate" HRQOL trajectory. The course of HRQOL over time in children with new-onset epilepsy appears to follow one of three different trajectories. Addressing the clinical and psychosocial determinants identified

  13. Association between Adolescent Substance Use and Obesity in Young Adulthood: A Group-based Dual Trajectory Analysis

    Science.gov (United States)

    Huang, David Y.C.; Lanza, H. Isabella; Anglin, M. Douglas

    2013-01-01

    Purpose This study investigated whether and how trajectories of substance use in adolescence were associated with obesity trajectories in young adulthood. We hypothesized that: (1) exposure to persistent substance use throughout adolescence may heighten obesity risk in young adulthood; and (2) such associations may differ once gender, ethnicity, socioeconomic status, and obesity status in adolescence, are considered. Methods The study included 5,141 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth and utilized biennial data across the 12 assessments (1986-2008) to examine trajectories of substance use behaviors (i.e., cigarette smoking, alcohol use, and marijuana use) from ages 12 to 18 and obesity trajectories from ages 20 to 24. Group-based dual trajectory modeling was applied to examine sequential associations of trajectories of each type of substance use behavior with obesity trajectories. Results Three distinctive trajectory patterns were respectively identified for cigarette smoking, alcohol use, and marijuana use from ages 12 to 18, as well as for obesity status (BMI ≥ 30) from ages 20 to 24. Taking into account gender, ethnicity, socioeconomic status, and obesity status in adolescence, adolescents with the most problematic smoking trajectory (High-decreasing) were more likely to exhibit a High-obesity trajectory from ages 20 to 24. Also, adolescents with an Increasing marijuana use trajectory were more likely to exhibit an Increased obesity trajectory in young adulthood. Conclusions The current study demonstrates that adolescent substance use is associated with subsequent obesity in young adulthood. The associations appear to differ based on type of substance use and patterns of use. PMID:23899428

  14. Identification of individual coherent sets associated with flow trajectories using coherent structure coloring

    Science.gov (United States)

    Schlueter-Kuck, Kristy L.; Dabiri, John O.

    2017-09-01

    We present a method for identifying the coherent structures associated with individual Lagrangian flow trajectories even where only sparse particle trajectory data are available. The method, based on techniques in spectral graph theory, uses the Coherent Structure Coloring vector and associated eigenvectors to analyze the distance in higher-dimensional eigenspace between a selected reference trajectory and other tracer trajectories in the flow. By analyzing this distance metric in a hierarchical clustering, the coherent structure of which the reference particle is a member can be identified. This algorithm is proven successful in identifying coherent structures of varying complexities in canonical unsteady flows. Additionally, the method is able to assess the relative coherence of the associated structure in comparison to the surrounding flow. Although the method is demonstrated here in the context of fluid flow kinematics, the generality of the approach allows for its potential application to other unsupervised clustering problems in dynamical systems such as neuronal activity, gene expression, or social networks.

  15. Changes in At-Risk American Men’s Crime and Substance Use Trajectories Following Fatherhood

    Science.gov (United States)

    Kerr, David C. R.; Capaldi, Deborah M.; Owen, Lee D.; Wiesner, Margit; Pears, Katherine C.

    2011-01-01

    Fatherhood can be a turning point in development and in men’s crime and substance use trajectories. At-risk boys (N = 206) were assessed annually from ages 12 to 31 years. Crime, arrest, and tobacco, alcohol, and marijuana use trajectories were examined. Marriage was associated with lower levels of crime and less frequent substance use. Following the birth of a first biological child, men’s crime trajectories showed slope decreases, and tobacco and alcohol use trajectories showed level decreases. The older men were when they became fathers, the greater the level decreases were in crime and alcohol use and the less the slope decreases were in tobacco and marijuana use. Patterns are consistent with theories of social control and social timetables. PMID:21984846

  16. NASA Double Asteroid Redirection Test (DART) Trajectory Validation and Robutness

    Science.gov (United States)

    Sarli, Bruno V.; Ozimek, Martin T.; Atchison, Justin A.; Englander, Jacob A.; Barbee, Brent W.

    2017-01-01

    The Double Asteroid Redirection Test (DART) mission will be the first to test the concept of a kinetic impactor. Several studies have been made on asteroid redirection and impact mitigation, however, to this date no mission tested the proposed concepts. An impact study on a representative body allows the measurement of the effects on the target's orbit and physical structure. With this goal, DART's objective is to verify the effectiveness of the kinetic impact concept for planetary defense. The spacecraft uses solar electric propulsion to escape Earth, fly by (138971) 2001 CB21 for impact rehearsal, and impact Didymos-B, the secondary body of the binary (65803) Didymos system. This work focuses on the heliocentric transfer design part of the mission with the validation of the baseline trajectory, performance comparison to other mission objectives, and assessment of the baseline robustness to missed thrust events. Results show a good performance of the selected trajectory for different mission objectives: latest possible escape date, maximum kinetic energy on impact, shortest possible time of flight, and use of an Earth swing-by. The baseline trajectory was shown to be robust to a missed thrust with 1% of fuel margin being enough to recover the mission for failures of more than 14 days.

  17. Benchmarking Foot Trajectory Estimation Methods for Mobile Gait Analysis

    Directory of Open Access Journals (Sweden)

    Julius Hannink

    2017-08-01

    Full Text Available Mobile gait analysis systems based on inertial sensing on the shoe are applied in a wide range of applications. Especially for medical applications, they can give new insights into motor impairment in, e.g., neurodegenerative disease and help objectify patient assessment. One key component in these systems is the reconstruction of the foot trajectories from inertial data. In literature, various methods for this task have been proposed. However, performance is evaluated on a variety of datasets due to the lack of large, generally accepted benchmark datasets. This hinders a fair comparison of methods. In this work, we implement three orientation estimation and three double integration schemes for use in a foot trajectory estimation pipeline. All methods are drawn from literature and evaluated against a marker-based motion capture reference. We provide a fair comparison on the same dataset consisting of 735 strides from 16 healthy subjects. As a result, the implemented methods are ranked and we identify the most suitable processing pipeline for foot trajectory estimation in the context of mobile gait analysis.

  18. Depressed trajectory SLBMs: A technical evaluation and arms control possibilities

    International Nuclear Information System (INIS)

    Gronlund, L.; Wright, D.C.

    1992-01-01

    SLBMs (sea-launched ballistic missiles) flown on depressed trajectories would have short flight times, comparable to escape times of bombers and launch times of ICBMs, thus raising the possibility of short time-of-flight (STOF) nuclear attacks. We assess the depressed trajectory (DT) capability of existing SLBMs by calculating the flight times, atmospheric loading on the booster, reentry heating on the reentry vehicle (RV), and degradation of accuracy for a DT SLBM. We find that current US and CIS SLBMs flown on depressed trajectories would have the capability to attack bomber bases at ranges of up to about 2,000 kilometers, and possibly at ranges up to 3,000 kilometers. To target bombers based furthest inland, a new high-velocity booster might be required, and attacking hardened targets would require a maneuvering RV (MaRV). We conclude that DT capabilities could be effectively controlled by the combination of an apogee restriction on the flight testing of existing SLBMs and bans on the development of high-velocity boosters and MaRVs, and that, in view of their inherent STOF capabilities, deep cuts in the number of SLBMs or their elimination might be desirable for an optimal minimum-deterrent force structure

  19. Trajectories of posttraumatic growth and depreciation after two major earthquakes.

    Science.gov (United States)

    Marshall, Emma M; Frazier, Patricia; Frankfurt, Sheila; Kuijer, Roeline G

    2015-03-01

    This study examined trajectories of posttraumatic growth or depreciation (i.e., positive or negative life change) in personal strength and relationships after 2 major earthquakes in Canterbury, New Zealand using group-based trajectory modeling. Participants completed questionnaires regarding posttraumatic growth or depreciation in personal strength and relationship domains 1 month after the first earthquake in September 2010 (N = 185) and 3 months (n = 156) and 12 months (n = 144) after the more severe February 2011 earthquake. Three classes of growth or depreciation patterns were found for both domains. For personal strength, most of the participants were grouped into a "no growth or depreciation" class and smaller proportions were grouped into either a "posttraumatic depreciation" or "posttraumatic growth" class. The 3 classes for relationships all reported posttraumatic growth, differing only in degree. None of the slopes were significant for any of the classes, indicating that levels of growth or depreciation reported after the first earthquake remained stable when assessed at 2 time points after the second earthquake. Multinomial logistic regression analyses examining pre- and postearthquake predictors of trajectory class membership revealed that those in the "posttraumatic growth" personal strength class were significantly younger and had significantly higher pre-earthquake mental health than those in the "posttraumatic depreciation" class. Sex was the only predictor of the relationship classes: No men were assigned to the "high posttraumatic growth" class. Implications and future directions are discussed. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  20. Mental health trajectories and related factors among perinatal women.

    Science.gov (United States)

    Lin, Pei-Chao; Hung, Chich-Hsiu

    2015-06-01

    To investigate Taiwanese women's mental health trajectories from the third trimester of pregnancy to four weeks postpartum and the correlations of these trajectories with perceived social support and demographic characteristics. Previous studies have reported differences between prenatal and postpartum mental health status. A repeated design study was conducted in a medical hospital in Southern Taiwan. One-hundred and ninety-four Taiwanese women completed the Chinese Health Questionnaire and Social Support Scale at the 36th prenatal week and first and fourth week postpartum. Three linear mental health trajectories for perinatal women were identified. Consistently poor perinatal mental health was reported by 16·0% of the participants. Less social support was associated with lower prenatal mental health scores. Younger age was a risk factor for consistently poor perinatal health. Vaginal delivery was associated with improved mental health after childbirth. Mental health was worse in the third trimester of pregnancy than postpartum. Less social support was associated with lower prenatal mental health scores, and this association was similarly distributed between women with consistently poor and improved mental health after birth. Health care providers should assess women's mental health status and provide timely interventions during the perinatal period. Social support should be provided for pregnant women, especially younger women or those with lower perceived social support. © 2015 John Wiley & Sons Ltd.

  1. Toddler hand preference trajectories predict 3-year language outcome.

    Science.gov (United States)

    Nelson, Eliza L; Gonzalez, Sandy L; Coxe, Stefany; Campbell, Julie M; Marcinowski, Emily C; Michel, George F

    2017-11-01

    A growing body of work suggests that early motor experience affects development in unexpected domains. In the current study, children's hand preference for role-differentiated bimanual manipulation (RDBM) was measured at monthly intervals from 18 to 24 months of age (N = 90). At 3 years of age, children's language ability was assessed using the Preschool Language Scales 5th edition (PLS™-5). Three distinct RDBM hand preference trajectories were identified using latent class growth analysis: (1) children with a left hand preference but a moderate amount of right hand use; (2) children with a right hand preference but a moderate amount of left hand use; and (3) children with a right hand preference and only a mild amount of left hand use. Stability over time within all three trajectories indicated that children did not change hand use patterns from 18 to 24 months. Children with the greatest amount of preferred (i.e., right) hand use demonstrated higher expressive language scores compared to children in both trajectories with moderate levels of non-preferred hand use. Children with the greatest amount of right hand use also had higher scores for receptive language compared to children with a right hand preference but moderate left hand use. Results support that consistency in handedness as measured by the amount of preferred hand use is related to distal language outcomes in development. © 2017 Wiley Periodicals, Inc.

  2. Parental nonstandard work schedules during infancy and children's BMI trajectories

    Directory of Open Access Journals (Sweden)

    Afshin Zilanawala

    2017-09-01

    Full Text Available Background: Empirical evidence has demonstrated adverse associations between parental nonstandard work schedules (i.e., evenings, nights, or weekends and child developmental outcomes. However, there are mixed findings concerning the relationship between parental nonstandard employment and children's body mass index (BMI, and few studies have incorporated information on paternal work schedules. Objective: This paper investigated BMI trajectories from early to middle childhood (ages 3-11 by parental work schedules at 9 months of age, using nationally representative cohort data from the United Kingdom. This study is the first to examine the link between nonstandard work schedules and children's BMI in the United Kingdom. Methods: We used data from the Millennium Cohort Study (2001‒2013, n = 13,021 to estimate trajectories in BMI, using data from ages 3, 5, 7, and 11 years. Joint parental work schedules and a range of biological, socioeconomic, and psychosocial covariates were assessed in the initial interviews at 9 months. Results: Compared to children in two-parent families where parents worked standard shifts, we found steeper BMI growth trajectories for children in two-parent families where both parents worked nonstandard shifts and children in single-parent families whose mothers worked a standard shift. Fathers' shift work, compared to standard shifts, was independently associated with significant increases in BMI. Conclusions: Future public health initiatives focused on reducing the risk of rapid BMI gain in childhood can potentially consider the disruptions to family processes resulting from working nonstandard hours. Contribution: Children in families in which both parents work nonstandard schedules had steeper BMI growth trajectories across the first decade of life. Fathers' nonstandard shifts were independently associated with increases in BMI.

  3. Trajectories and outcomes among children with special health care needs.

    Science.gov (United States)

    Quach, Jon; Jansen, Pauline W; Mensah, Fiona K; Wake, Melissa

    2015-04-01

    Outcomes for children with special health care needs (SHCN) can vary by their patterns and persistence over time. We aimed to empirically establish typical SHCN trajectories throughout childhood and their predictive relationships with child and parent outcomes. The 2 cohorts of the nationally representative Longitudinal Study of Australian Children were recruited in 2004 at ages 0 to 1 (n = 5107, B cohort) and 4 to 5 years (n = 4983, K cohort). The parent-reported Children With SHCN Screener (Short Form) was completed at each of 4 biennial waves. Wave 4 outcomes were parent-reported behavior and health-related quality of life, teacher-reported learning, and directly assessed cognition. Both parents self-reported mental distress. We derived intracohort trajectories by using latent class analysis in Mplus. We compared mean outcome scores across trajectories by using linear regression, adjusting for socioeconomic position. Four distinct SHCN trajectories were replicated in both cohorts: persistent (B 6.8%, K 8.7%), emerging (B 4.1%, K 11.5%), transient (B 7.9%, K 4.2%), and none (B 81.3%, K 75.6%). Every outcome was adversely affected except fathers' mental health. From infancy to age 6 to 7 years, the persistent and emerging groups had similarly poor outcomes. From age 4 and 5 to 10 and 11 years, outcomes were incrementally poorer on moving from none to transient to emerging and to persistent SHCN. Effect sizes were largest for behavior, learning, and psychosocial outcomes. Adverse outcomes are shaped more by cumulative burden than point prevalence of SHCNs. In addition to providing care according to a child's need at any given time, prioritizing care toward persistent SHCNs may have the biggest benefits for children and parents. Copyright © 2015 by the American Academy of Pediatrics.

  4. User oriented trajectory search for trip recommendation

    KAUST Repository

    Shang, Shuo

    2012-01-01

    Trajectory sharing and searching have received significant attentions in recent years. In this paper, we propose and investigate a novel problem called User Oriented Trajectory Search (UOTS) for trip recommendation. In contrast to conventional trajectory search by locations (spatial domain only), we consider both spatial and textual domains in the new UOTS query. Given a trajectory data set, the query input contains a set of intended places given by the traveler and a set of textual attributes describing the traveler\\'s preference. If a trajectory is connecting/close to the specified query locations, and the textual attributes of the trajectory are similar to the traveler\\'e preference, it will be recommended to the traveler for reference. This type of queries can bring significant benefits to travelers in many popular applications such as trip planning and recommendation. There are two challenges in the UOTS problem, (i) how to constrain the searching range in two domains and (ii) how to schedule multiple query sources effectively. To overcome the challenges and answer the UOTS query efficiently, a novel collaborative searching approach is developed. Conceptually, the UOTS query processing is conducted in the spatial and textual domains alternately. A pair of upper and lower bounds are devised to constrain the searching range in two domains. In the meantime, a heuristic searching strategy based on priority ranking is adopted for scheduling the multiple query sources, which can further reduce the searching range and enhance the query efficiency notably. Furthermore, the devised collaborative searching approach can be extended to situations where the query locations are ordered. The performance of the proposed UOTS query is verified by extensive experiments based on real and synthetic trajectory data in road networks. © 2012 ACM.

  5. Shadowing of physical trajectories in chaotic dynamics: Containment and refinement

    International Nuclear Information System (INIS)

    Grebogi, C.; Hammel, S.M.; Yorke, J.A.; Sauer, T.

    1990-01-01

    For a chaotic system, a noisy trajectory diverges rapidly from the true trajectory with the same initial condition. To understand in what sense the noisy trajectory reflects the true dynamics of the actual system, we developed a rigorous procedure to show that some true trajectories remain close to the noisy one for long times. The procedure involves a combination of containment, which establishes the existence of an uncountable number of true trajectories close to the noisy one, and refinement, which produces a less noisy trajectory. Our procedure is applied to noisy chaotic trajectories of the standard map and the driven pendulum

  6. THE DYNAMIC MODEL FOR CONTROL OF STUDENT’S LEARNING INDIVIDUAL TRAJECTORY

    Directory of Open Access Journals (Sweden)

    A. A. Mitsel

    2015-01-01

    Full Text Available In connection with the transition of the educational system to a competence-oriented approach, the problem of learning outcomes assessment and creating an individual learning trajectory of a student has become relevant. Its solution requires the application of modern information technologies. The third generation of Federal state educational standards of higher professional education (FSES HPE defines the requirements for the results of Mastering the basic educational programs (BEP. According to FSES HPE up to 50% of subjects have a variable character, i.e. depend on the choice of a student. It significantly influences on the results of developing various competencies. The problem of forming student’s learning trajectory is analyzed in general and the choice of an individual direction was studied in details. Various methods, models and algorithms of the student’s individual learning trajectory formation were described. The analysis of the model of educational process organization in terms of individual approach makes it possible to develop a decision support system (DSS. DSS is a set of interrelated programs and data used for analysis of situation, development of alternative solutions and selection of the most acceptable alternative. DSSs are often used when building individual learning path, because this task can be considered as a discrete multi-criteria problem, creating a significant burden on the decision maker. A new method of controlling the learning trajectory has been developed. The article discusses problem statement and solution of determining student’s optimal individual educational trajectory as a dynamic model of learning trajectory control, which uses score assessment to construct a sequence of studied subjects. A new model of management learning trajectory is based on dynamic models for tracking the reference trajectory. The task can be converted to an equivalent model of linear programming, for which a reliable solution

  7. Developmental trajectories of irritability and bidirectional associations with maternal depression.

    Science.gov (United States)

    Wiggins, Jillian Lee; Mitchell, Colter; Stringaris, Argyris; Leibenluft, Ellen

    2014-11-01

    Irritability is a dimensional trait in typical development and a common presenting symptom in many psychiatric disorders, including depression. However, little is known about the developmental trajectory of irritability or how child irritability interacts with maternal depression. The present study identifies classes of irritability trajectories from toddlerhood to middle childhood; characterizes maternal depression and other family, social environment, and child variables within each irritability trajectory class; and, as a more exploratory analysis, examines bidirectional associations between maternal depression and child irritability. A total of 4,898 families from the Fragile Families and Child Wellbeing Study reported on irritability symptoms at ages 3, 5, and 9 years, assessed with items from the Child Behavior Checklist. Parental major depressive episode was assessed using the Composite International Diagnostic Interview-Short Form at child ages 1, 3, 5, and 9 years. A latent class growth analysis identified 5 irritability classes: low decreasing; moderate decreasing; high steady; initially very high, then decreasing; and high increasing. Children with more severe irritability trajectories are more likely to have mothers with recurrent depression, and, with the exception of the most severe (high increasing irritability) class, were more likely to have mothers who were exposed to violence. Moreover, paternal depression and alcohol abuse, as well as maternal drug and alcohol abuse, were also risk factors for membership in the more severe irritability classes. A latent auto-regressive cross-lag model showed that child irritability at ages 3 and 5 years is associated with increased mother depression at ages 5 and 9, respectively. Conversely, mother depression at child ages 1 and 3 years is associated with increased child irritability at 3 and 5. Irritability development across toddlerhood and middle childhood has 5 main trajectory types, which differ on maternal

  8. Estimating trajectories of energy intake through childhood and adolescence using linear-spline multilevel models.

    Science.gov (United States)

    Anderson, Emma L; Tilling, Kate; Fraser, Abigail; Macdonald-Wallis, Corrie; Emmett, Pauline; Cribb, Victoria; Northstone, Kate; Lawlor, Debbie A; Howe, Laura D

    2013-07-01

    Methods for the assessment of changes in dietary intake across the life course are underdeveloped. We demonstrate the use of linear-spline multilevel models to summarize energy-intake trajectories through childhood and adolescence and their application as exposures, outcomes, or mediators. The Avon Longitudinal Study of Parents and Children assessed children's dietary intake several times between ages 3 and 13 years, using both food frequency questionnaires (FFQs) and 3-day food diaries. We estimated energy-intake trajectories for 12,032 children using linear-spline multilevel models. We then assessed the associations of these trajectories with maternal body mass index (BMI), and later offspring BMI, and also their role in mediating the relation between maternal and offspring BMIs. Models estimated average and individual energy intake at 3 years, and linear changes in energy intake from age 3 to 7 years and from age 7 to 13 years. By including the exposure (in this example, maternal BMI) in the multilevel model, we were able to estimate the average energy-intake trajectories across levels of the exposure. When energy-intake trajectories are the exposure for a later outcome (in this case offspring BMI) or a mediator (between maternal and offspring BMI), results were similar, whether using a two-step process (exporting individual-level intercepts and slopes from multilevel models and using these in linear regression/path analysis), or a single-step process (multivariate multilevel models). Trajectories were similar when FFQs and food diaries were assessed either separately, or when combined into one model. Linear-spline multilevel models provide useful summaries of trajectories of dietary intake that can be used as an exposure, outcome, or mediator.

  9. Trajectory planning and trajectory tracking for a small-scale helicopter in autorotation

    NARCIS (Netherlands)

    Taamallah, Skander; Bombois, Xavier; Van den Hof, Paul M.J.

    2017-01-01

    The design of a high-performance guidance and control system for a small-scale helicopterUnmanned Aerial Vehicle (UAV), with an engine OFF flight condition (i.e. autorotation), is known to be a challenging task. It is the purpose of this paper to present a Trajectory Planning (TP) and Trajectory

  10. PRESS: A Novel Framework of Trajectory Compression in Road Networks

    OpenAIRE

    Song, Renchu; Sun, Weiwei; Zheng, Baihua; Zheng, Yu

    2014-01-01

    Location data becomes more and more important. In this paper, we focus on the trajectory data, and propose a new framework, namely PRESS (Paralleled Road-Network-Based Trajectory Compression), to effectively compress trajectory data under road network constraints. Different from existing work, PRESS proposes a novel representation for trajectories to separate the spatial representation of a trajectory from the temporal representation, and proposes a Hybrid Spatial Compression (HSC) algorithm ...

  11. 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

  12. 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.

  13. The trajectory control in the SLC linac

    International Nuclear Information System (INIS)

    Hsu, I.C.; Adolphsen, C.E.; Himel, T.M.; Seeman, J.T.

    1991-05-01

    Due to wake field effects, the trajectories of accelerated beams in the Linac should be well maintained to avoid severe beam breakup. In order to maintain a small emittance at the end of the Linac, the tolerance on the trajectory deviations become tighter when the beam intensities increase. The existing two beam trajectory correction method works well when the theoretical model agrees with the real machine lattice. Unknown energy deviations along the linac as well as wake field effects can cause the real lattice to deviate from the model. This makes the trajectory correction difficult. Several automated procedures have been developed to solve these problems. They are: an automated procedure to frequently steer the whole Linac by dividing the Linac into several small regions; an automated procedure to empirically correct the model to fit the real lattice and eight trajectory correcting feedback loops along the linac and steering through the collimator region with restricted corrector strengths and a restricted number of correctors. 6 refs., 2 figs

  14. Spatiotemporal Interpolation Methods for Solar Event Trajectories

    Science.gov (United States)

    Filali Boubrahimi, Soukaina; Aydin, Berkay; Schuh, Michael A.; Kempton, Dustin; Angryk, Rafal A.; Ma, Ruizhe

    2018-05-01

    This paper introduces four spatiotemporal interpolation methods that enrich complex, evolving region trajectories that are reported from a variety of ground-based and space-based solar observatories every day. Our interpolation module takes an existing solar event trajectory as its input and generates an enriched trajectory with any number of additional time–geometry pairs created by the most appropriate method. To this end, we designed four different interpolation techniques: MBR-Interpolation (Minimum Bounding Rectangle Interpolation), CP-Interpolation (Complex Polygon Interpolation), FI-Interpolation (Filament Polygon Interpolation), and Areal-Interpolation, which are presented here in detail. These techniques leverage k-means clustering, centroid shape signature representation, dynamic time warping, linear interpolation, and shape buffering to generate the additional polygons of an enriched trajectory. Using ground-truth objects, interpolation effectiveness is evaluated through a variety of measures based on several important characteristics that include spatial distance, area overlap, and shape (boundary) similarity. To our knowledge, this is the first research effort of this kind that attempts to address the broad problem of spatiotemporal interpolation of solar event trajectories. We conclude with a brief outline of future research directions and opportunities for related work in this area.

  15. 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.

  16. Trajectories of Depressive Symptoms in Older Adults and Risk of Dementia.

    Science.gov (United States)

    Kaup, Allison R; Byers, Amy L; Falvey, Cherie; Simonsick, Eleanor M; Satterfield, Suzanne; Ayonayon, Hilsa N; Smagula, Stephen F; Rubin, Susan M; Yaffe, Kristine

    2016-05-01

    Depression has been identified as a risk factor for dementia. However, most studies have measured depressive symptoms at only one time point, and older adults may show different patterns of depressive symptoms over time. To investigate the association between trajectories of depressive symptoms and risk of dementia in older adults. This was a prospective cohort investigation of black and white community-dwelling older adults in the Health, Aging, and Body Composition study. Participants were enrolled between May 1997 and June 1998 and followed up through 2001-2002. The dates of this analysis were September 2014 to December 2015. The setting was community research centers in Memphis, Tennessee, and Pittsburgh, Pennsylvania. Trajectories of depressive symptoms were assessed from baseline to year 5. Symptoms were measured with the Center for Epidemiologic Studies Depression Scale Short Form, and trajectories were calculated using latent class growth curve analysis. Incident dementia through year 11, determined by dementia medication use, hospital records, or significant cognitive decline (≥1.5 SD race-specific decline on the Modified Mini-Mental State Examination). We examined the association between depressive symptom trajectories and dementia incidence using Cox proportional hazards regression models adjusted for demographics, health factors that differed between groups, and cognition during the depressive symptom assessment period (baseline to year 5). The analytic cohort included 2488 black and white older adults with repeated depressive symptom assessments from baseline to year 5 who were free of dementia throughout that period. Their mean (SD) age at baseline was 74.0 (2.8) years, and 53.1% (n = 1322) were female. The following 3 depressive symptom trajectories were identified: consistently minimal symptoms (62.0% [n = 1542] of participants), moderate and increasing symptoms (32.2% [n = 801] of participants), and high and increasing symptoms (5

  17. Long-term trajectories of positive and negative symptoms in first episode psychosis

    DEFF Research Database (Denmark)

    Austin, Stephen; Mors, Ole; Budtz-Jørgensen, Esben

    2015-01-01

    OBJECTIVE: Knowledge about course of illness can help clinicians to develop effective interventions and improve treatment outcomes. The goal of this study was to construct positive and negative symptom trajectories based on structured clinical assessments collected over 10years within a cohort....... Positive symptoms showed a general pattern of reduction and stabilization over time while negative symptoms typically showed less variation over the ten years. Results have implications for the focus, timing and length of interventions in first episode psychosis....... was assessed using the Scales for Assessment of Positive and Negative Symptoms. Symptom trajectories were constructed using Latent Class Analysis. RESULTS: Five distinct trajectories were identified for positive symptoms (response - 47%, delayed response - 12%, relapse - 15%, non-response - 13% and episodic...

  18. Effective Online Group Discovery in Trajectory Databases

    DEFF Research Database (Denmark)

    Li, Xiaohui; Ceikute, Vaida; Jensen, Christian S.

    2013-01-01

    GPS-enabled devices are pervasive nowadays. Finding movement patterns in trajectory data stream is gaining in importance. We propose a group discovery framework that aims to efficiently support the online discovery of moving objects that travel together. The framework adopts a sampling-independen......GPS-enabled devices are pervasive nowadays. Finding movement patterns in trajectory data stream is gaining in importance. We propose a group discovery framework that aims to efficiently support the online discovery of moving objects that travel together. The framework adopts a sampling......-independent approach that makes no assumptions about when positions are sampled, gives no special importance to sampling points, and naturally supports the use of approximate trajectories. The framework's algorithms exploit state-of-the-art, density-based clustering (DBScan) to identify groups. The groups are scored...

  19. Dual unitarization scheme with several trajectories

    International Nuclear Information System (INIS)

    Chaichiam, M.; Hayashi, M.

    1977-12-01

    Consequences of bootstrap with several input Regge trajectories are investigated. We find that in a formal treatment of bootstrap the consistency requires the intercept of output Pomeron pole in the one-dimensional case to be larger than one: αsub(B)(0) > 1, a situation reminiscent of the one in the Reggeon field theory. Symmetry breakings of the Pomeron couplings are derived. These couplings coincide with those of the f-dominated Pomeron model of Carlitz-Green-Zee in the approximation, when in the unitarity loops only highest Regge trajectories are included. The case when all possible trajectories are exchanged is also discussed. Predictions of dual unitary model for the slopes of differential cross section for diffractive scattering are made which differ from the ones of the CGZ model. Comparison with the experimentally available data is done. (author)

  20. Classical trajectories and quantum field theory

    International Nuclear Information System (INIS)

    Vitiello, Giuseppe; Istituto Nazionale di Fisica Nucleare, Salerno

    2005-01-01

    The density matrix and the Wigner function formalism requires the doubling of the degrees of freedom in quantum mechanics (QM) and quantum field theory (QFT). The doubled degrees of freedom play the role of the thermal bath or environment degrees of freedom and are entangled with the system degrees of freedom. They also account for quantum noise in the fluctuating random forces in the system-environment coupling. The algebraic structure of QFT turns out to be the one of the deformed Hopf algebra. In such a frame, the trajectories in the space of the unitarily inequivalent representations of the canonical commutation relations turn out to be classical trajectories and, under convenient conditions, they may exhibit properties typical of classical chaotic trajectories in nonlinear dynamics. The quantum Brownian motion and the two-slit experiment in QM are discussed in connection with the doubling of the degrees of freedom. (author)

  1. A new trajectory correction technique for linacs

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.; Ruth, R.D.

    1990-06-01

    In this paper, we describe a new trajectory correction technique for high energy linear accelerators. Current correction techniques force the beam trajectory to follow misalignments of the Beam Position Monitors. Since the particle bunch has a finite energy spread and particles with different energies are deflected differently, this causes ''chromatic'' dilution of the transverse beam emittance. The algorithm, which we describe in this paper, reduces the chromatic error by minimizing the energy dependence of the trajectory. To test the method we compare the effectiveness of our algorithm with a standard correction technique in simulations on a design linac for a Next Linear Collider. The simulations indicate that chromatic dilution would be debilitating in a future linear collider because of the very small beam sizes required to achieve the necessary luminosity. Thus, we feel that this technique will prove essential for future linear colliders. 3 refs., 6 figs., 2 tabs

  2. Robot Trajectories Comparison: A Statistical Approach

    Directory of Open Access Journals (Sweden)

    A. Ansuategui

    2014-01-01

    Full Text Available The task of planning a collision-free trajectory from a start to a goal position is fundamental for an autonomous mobile robot. Although path planning has been extensively investigated since the beginning of robotics, there is no agreement on how to measure the performance of a motion algorithm. This paper presents a new approach to perform robot trajectories comparison that could be applied to any kind of trajectories and in both simulated and real environments. Given an initial set of features, it automatically selects the most significant ones and performs a statistical comparison using them. Additionally, a graphical data visualization named polygraph which helps to better understand the obtained results is provided. The proposed method has been applied, as an example, to compare two different motion planners, FM2 and WaveFront, using different environments, robots, and local planners.

  3. Robot Trajectories Comparison: A Statistical Approach

    Science.gov (United States)

    Ansuategui, A.; Arruti, A.; Susperregi, L.; Yurramendi, Y.; Jauregi, E.; Lazkano, E.; Sierra, B.

    2014-01-01

    The task of planning a collision-free trajectory from a start to a goal position is fundamental for an autonomous mobile robot. Although path planning has been extensively investigated since the beginning of robotics, there is no agreement on how to measure the performance of a motion algorithm. This paper presents a new approach to perform robot trajectories comparison that could be applied to any kind of trajectories and in both simulated and real environments. Given an initial set of features, it automatically selects the most significant ones and performs a statistical comparison using them. Additionally, a graphical data visualization named polygraph which helps to better understand the obtained results is provided. The proposed method has been applied, as an example, to compare two different motion planners, FM2 and WaveFront, using different environments, robots, and local planners. PMID:25525618

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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...

  10. Bohmian trajectories for an evaporating blackhole

    Energy Technology Data Exchange (ETDEWEB)

    Acacio de Barros, J. [Departamento de Fisica, Instituto de Ciencias Exatas, Universidade Federal de Juiz de Fora, CEP 36036-330, Juiz de Fora, Minas Gerais (Brazil)]. E-mail: acacio@fisica.ufjf.br; Oliveira-Neto, G. [Departamento de Fisica, Instituto de Ciencias Exatas, Universidade Federal de Juiz de Fora, CEP 36036-330, Juiz de Fora, Minas Gerais (Brazil)]. E-mail: gilneto@fisica.ufjf.br; Vale, T.B. [Departamento de Fisica, Instituto de Ciencias Exatas, Universidade Federal de Juiz de Fora, CEP 36036-330, Juiz de Fora, Minas Gerais (Brazil)]. E-mail: tiberio@fisica.ufjf.br

    2005-03-14

    In this work we apply Bohm's interpretation to the quantized spherically-symmetric blackhole coupled to a massless scalar field. We show that the quantum trajectories for linear combinations of eigenstates of the Wheeler-DeWitt equation form a large set of different curves that cannot be predicted by the standard interpretation of quantum mechanics. Some of them are consistent with the expected value of the time derivative of the mass, whereas other trajectories are not, because they represent blackholes that switch from absorbing to emitting regimes.

  11. Optimization approaches for robot trajectory planning

    Directory of Open Access Journals (Sweden)

    Carlos Llopis-Albert

    2018-03-01

    Full Text Available The development of optimal trajectory planning algorithms for autonomous robots is a key issue in order to efficiently perform the robot tasks. This problem is hampered by the complex environment regarding the kinematics and dynamics of robots with several arms and/or degrees of freedom (dof, the design of collision-free trajectories and the physical limitations of the robots. This paper presents a review about the existing robot motion planning techniques and discusses their pros and cons regarding completeness, optimality, efficiency, accuracy, smoothness, stability, safety and scalability.

  12. On Discovery of Gathering Patterns from Trajectories

    DEFF Research Database (Denmark)

    Zheng, Kai; Zheng, Yu; Yuan, Jing

    2013-01-01

    The increasing pervasiveness of location-acquisition technologies has enabled collection of huge amount of trajectories for almost any kind of moving objects. Discovering useful patterns from their movement behaviours can convey valuable knowledge to a variety of critical applications. In this li......The increasing pervasiveness of location-acquisition technologies has enabled collection of huge amount of trajectories for almost any kind of moving objects. Discovering useful patterns from their movement behaviours can convey valuable knowledge to a variety of critical applications...

  13. 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.

  14. UAV Trajectory Modeling Using Neural Networks

    Science.gov (United States)

    Xue, Min

    2017-01-01

    Large amount of small Unmanned Aerial Vehicles (sUAVs) are projected to operate in the near future. Potential sUAV applications include, but not limited to, search and rescue, inspection and surveillance, aerial photography and video, precision agriculture, and parcel delivery. sUAVs are expected to operate in the uncontrolled Class G airspace, which is at or below 500 feet above ground level (AGL), where many static and dynamic constraints exist, such as ground properties and terrains, restricted areas, various winds, manned helicopters, and conflict avoidance among sUAVs. How to enable safe, efficient, and massive sUAV operations at the low altitude airspace remains a great challenge. NASA's Unmanned aircraft system Traffic Management (UTM) research initiative works on establishing infrastructure and developing policies, requirement, and rules to enable safe and efficient sUAVs' operations. To achieve this goal, it is important to gain insights of future UTM traffic operations through simulations, where the accurate trajectory model plays an extremely important role. On the other hand, like what happens in current aviation development, trajectory modeling should also serve as the foundation for any advanced concepts and tools in UTM. Accurate models of sUAV dynamics and control systems are very important considering the requirement of the meter level precision in UTM operations. The vehicle dynamics are relatively easy to derive and model, however, vehicle control systems remain unknown as they are usually kept by manufactures as a part of intellectual properties. That brings challenges to trajectory modeling for sUAVs. How to model the vehicle's trajectories with unknown control system? This work proposes to use a neural network to model a vehicle's trajectory. The neural network is first trained to learn the vehicle's responses at numerous conditions. Once being fully trained, given current vehicle states, winds, and desired future trajectory, the neural

  15. Long-term trajectories of posttraumatic stress disorder in veterans: the role of social resources.

    Science.gov (United States)

    Karstoft, Karen-Inge; Armour, Cherie; Elklit, Ask; Solomon, Zahava

    2013-12-01

    To (1) identify long-term trajectories of combat-induced posttraumatic stress disorder (PTSD) symptoms over a 20-year period from 1983 to 2002 in veterans with and without combat stress reaction (CSR) and (2) identify social predictors of these trajectories. A latent growth mixture modeling analysis on PTSD symptoms was conducted to identify PTSD trajectories and predictors. PTSD was defined according to DSM-III and assessed through the PTSD Inventory. Israeli male veterans with (n = 369) and without (n = 306) CSR were queried at 1, 2, and 20 years after war about combat exposure, military unit support, family environment, and social reintegration. For both study groups, we identified 4 distinct trajectories with varying prevalence across groups: resilience (CSR = 34.4%, non-CSR = 76.5%), recovery (CSR = 36.3%, non-CSR = 10.5%), delayed onset (CSR = 8.4%, non-CSR = 6.9%), and chronicity (CSR = 20.9%, non-CSR = 6.2%). Predictors of trajectories in both groups included perception of war threat (ORs = 1.59-2.47, P values ≤ .30), and negative social reintegration (ORs = 0.24-0.51, P values ≤ .047). Social support was associated with symptomatology only in the CSR group (ORs = 0.40-0.61, P values ≤ .045), while family coherence was predictive of symptomatology in the non-CSR group (OR = 0.76, P = .015) but not in the CSR group. Findings confirmed heterogeneity of long-term sequelae of combat, revealing 4 trajectories of resilience, recovery, delay, and chronicity in veterans with and without CSR. Symptomatic trajectories were more prevalent for the CSR group, suggesting that acute functional impairment predicts pathological outcomes. Predictors of symptomatic trajectories included perceived threat and social resources at the family, network, and societal levels. © Copyright 2013 Physicians Postgraduate Press, Inc.

  16. Economic Motivations for Master’s Students’ Choice of Educational, Scientific and Professional Trajectories

    Directory of Open Access Journals (Sweden)

    Daniil Gennadyevich Sandler

    2016-06-01

    Full Text Available The article examines the motivations for Master’s students’ choice of individual trajectories. In the course of their studies, the students’ trajectories have educational, scientific and professional aspects. Educational, scientific and professional students’ trajectories determine a system of interaction between master’s students and other people in the context of educational process (teachers, other students and beyond it (employers, research workers from Russian and foreign universities. The authors emphasize the importance of studying the master’s students’ individual trajectories from both scientific (identifying the peculiarities of students’ trajectories formation and development and practical points of view (investments to master’s students to enhance the professional competence in the regional labour market. The authors have analysed the master’s students’ individual trajectories on the basis of monitoring data obtained from the survey carried out in February and December 2014. The master’s students’ assessments allowed to identify what educational experience they were able to get during the education and whether their experience met their expectations. The master’s students’ economic expectations are examined during the implementation of educational and professional trajectories. The analysis of the results has shown that the biggest gap between the expectations and the experience of the master’s students was found according to the criteria related to the student’s scientific trajectory and opportunities to participate in the internationalisation processes. The results of the research may be used to improve the master’s programmes taking into account the revealed master’s students’ expectations, as well as to ensure highly qualified professionals in the labour market and for the effective investments to the human capital by the government authorities

  17. Criminal Trajectories of White-collar Offenders

    NARCIS (Netherlands)

    van Onna, J.; van der Geest, V.R.; Huisman, W.; Denkers, A.J.M.

    2014-01-01

    Objectives:This article analyzes the criminal development and sociodemographic and criminal profile of a sample of prosecuted white-collar offenders. It identifies trajectory groups and describes their profiles based on crime, sociodemographic, and selection offence characteristics.Methods:The

  18. Graphical Method for Determining Projectile Trajectory

    Science.gov (United States)

    Moore, J. C.; Baker, J. C.; Franzel, L.; McMahon, D.; Songer, D.

    2010-01-01

    We present a nontrigonometric graphical method for predicting the trajectory of a projectile when the angle and initial velocity are known. Students enrolled in a general education conceptual physics course typically have weak backgrounds in trigonometry, making inaccessible the standard analytical calculation of projectile range. Furthermore,…

  19. Propositional Optimal Trajectory Programming for Improving Stability ...

    African Journals Online (AJOL)

    Propositional Optimal Trajectory Programming for Improving Stability of Hermite Definite Control System. ... PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ONLINE (AJOL) ... Knowledge of systems operation subjected to heat diffusion constraints is required of systems analysts. In an instance that ...

  20. FEL Trajectory Analysis for the VISA Experiment

    International Nuclear Information System (INIS)

    Nuhn, Heinz-Dieter

    1998-01-01

    The Visual to Infrared SASE Amplifier (VISA) [1] FEL is designed to achieve saturation at radiation wavelengths between 800 and 600 nm with a 4-m pure permanent magnet undulator. The undulator comprises four 99-cm segments each of which has four FODO focusing cells superposed on the beam by means of permanent magnets in the gap alongside the beam. Each segment will also have two beam position monitors and two sets of x-y dipole correctors. The trajectory walk-off in each segment will be reduced to a value smaller than the rms beam radius by means of magnet sorting, precise fabrication, and post-fabrication shimming and trim magnets. However, this leaves possible inter-segment alignment errors. A trajectory analysis code has been used in combination with the FRED3D [2] FEL code to simulate the effect of the shimming procedure and segment alignment errors on the electron beam trajectory and to determine the sensitivity of the FEL gain process to trajectory errors. The paper describes the technique used to establish tolerances for the segment alignment

  1. Academic Trajectories of Newcomer Immigrant Youth

    Science.gov (United States)

    Suarez-Orozco, Carola; Gaytan, Francisco X.; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

    2010-01-01

    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…

  2. 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…

  3. APT: Action localization Proposals from dense Trajectories

    NARCIS (Netherlands)

    van Gemert, J.C.; Jain, M.; Gati, E.; Snoek, C.G.M.; Xie, X.; Jones, M.W.; Tam, G.K.L.

    2015-01-01

    This paper is on action localization in video with the aid of spatio-temporal proposals. To alleviate the computational expensive video segmentation step of existing proposals, we propose bypassing the segmentations completely by generating proposals directly from the dense trajectories used to

  4. 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.

  5. Equilibrium sampling by reweighting nonequilibrium simulation trajectories.

    Science.gov (United States)

    Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin

    2016-03-01

    Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.

  6. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    We present a detailed analysis of the motion of test particle in the gravitational field of cosmic strings in different situations using the Hamilton–Jacobi (H–J) formalism. We have discussed the trajectories near static cosmic string, cosmic string in Brans–Dicke theory and cosmic string in dilaton gravity.

  7. Classical trajectory methods in molecular collisions

    International Nuclear Information System (INIS)

    Porter, R.N.; Raff, L.M.

    1976-01-01

    The discussion of classical trajectory methods in molecular collisions includes classical dynamics, Hamiltonian mechanics, classical scattering cross sections and rate coefficients, statistical averaging, the selection of initial states, integration of equations of motion, analysis of final states, consecutive collisions, and the prognosis for classical molecular scattering calculations. 61 references

  8. Improved transition models for cepstral trajectories

    CSIR Research Space (South Africa)

    Badenhorst, J

    2012-11-01

    Full Text Available We improve on a piece-wise linear model of the trajectories of Mel Frequency Cepstral Coefficients, which are commonly used as features in Automatic Speech Recognition. For this purpose, we have created a very clean single-speaker corpus, which...

  9. Trajectory Optimization for Differential Flat Systems

    OpenAIRE

    Kahina Louadj; Benjamas Panomruttanarug; Alexandre Carlos Brandao Ramos; Felix Mora-Camino

    2016-01-01

    International audience; The purpose of this communication is to investigate the applicability of Variational Calculus to the optimization of the operation of differentially flat systems. After introducingcharacteristic properties of differentially flat systems, the applicability of variational calculus to the optimization of flat output trajectories is displayed. Two illustrative examples are also presented.

  10. 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...

  11. 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

  12. The emergence of an electric mobility trajectory

    NARCIS (Netherlands)

    Dijk, M.; Orsato, R.J.; Kemp, R.P.M.

    2013-01-01

    In this paper, we analyse the emergence of a trajectory of electric mobility. We describe developments in electric vehicles before and after 2005. The central thesis of the paper is that electric mobility has crossed a critical threshold and is benefiting from various developments whose influence

  13. Parallel Aircraft Trajectory Optimization with Analytic Derivatives

    Science.gov (United States)

    Falck, Robert D.; Gray, Justin S.; Naylor, Bret

    2016-01-01

    Trajectory optimization is an integral component for the design of aerospace vehicles, but emerging aircraft technologies have introduced new demands on trajectory analysis that current tools are not well suited to address. Designing aircraft with technologies such as hybrid electric propulsion and morphing wings requires consideration of the operational behavior as well as the physical design characteristics of the aircraft. The addition of operational variables can dramatically increase the number of design variables which motivates the use of gradient based optimization with analytic derivatives to solve the larger optimization problems. In this work we develop an aircraft trajectory analysis tool using a Legendre-Gauss-Lobatto based collocation scheme, providing analytic derivatives via the OpenMDAO multidisciplinary optimization framework. This collocation method uses an implicit time integration scheme that provides a high degree of sparsity and thus several potential options for parallelization. The performance of the new implementation was investigated via a series of single and multi-trajectory optimizations using a combination of parallel computing and constraint aggregation. The computational performance results show that in order to take full advantage of the sparsity in the problem it is vital to parallelize both the non-linear analysis evaluations and the derivative computations themselves. The constraint aggregation results showed a significant numerical challenge due to difficulty in achieving tight convergence tolerances. Overall, the results demonstrate the value of applying analytic derivatives to trajectory optimization problems and lay the foundation for future application of this collocation based method to the design of aircraft with where operational scheduling of technologies is key to achieving good performance.

  14. Understanding adolescent personality pathology from growth trajectories of childhood oddity.

    Science.gov (United States)

    De Clercq, Barbara; Verbeke, Lize; De Caluwé, Elien; Vercruysse, Tom; Hofmans, Joeri

    2017-10-01

    Research on developmental trajectories of early maladaptive features for understanding later personality disorders (PDs) is increasingly recognized as an important study area. The course of early odd features is highly relevant in this regard, as only a few researchers have addressed childhood oddity in the context of emerging PDs. Using latent growth modeling, the current study explores growth parameters of odd features in a mixed sample of Flemish community and referred children (N = 485) across three measurement waves with 1-year time intervals. Personality pathology was assessed at a fourth assessment point in adolescence. Beyond a general declining trend in oddity characteristics, the results demonstrated that both an early onset and an increasing trend of oddity-related characteristics over time are independent predictors of adolescent PDs. Childhood oddity tends to be the most manifest precursor for PDs with a core oddity feature (i.e., the schizotypal and borderline PD), but also appears to predict most of the other DSM-5 PDs. Results are discussed from an overarching developmental framework on PDs (Cicchetti, 2014), specifically focusing on the principle of multifinality. From a clinical perspective, the significance of increasing or steady-high childhood oddity trajectories for adolescent PDs highlights the relevance of systematic screening processes across time.

  15. Trajectory Design for the Transiting Exoplanet Survey Satellite (TESS)

    Science.gov (United States)

    Dichmann, Donald J.; Parker, Joel; Williams, Trevor; Mendelsohn, Chad

    2014-01-01

    The Transiting Exoplanet Survey Satellite (TESS) is a National Aeronautics and Space Administration (NASA) mission launching in 2017. TESS will travel in a highly eccentric orbit around Earth, with initial perigee radius near 17 Earth radii (Re) and apogee radius near 59 Re. The orbit period is near 2:1 resonance with the Moon, with apogee nearly 90 degrees out-of-phase with the Moon, in a configuration that has been shown to be operationally stable. TESS will execute phasing loops followed by a lunar flyby, with a final maneuver to achieve 2:1 resonance with the Moon. The goals of a resonant orbit with long-term stability, short eclipses and limited oscillations of perigee present significant challenges to the trajectory design. To rapidly assess launch opportunities, we adapted the SWM76 launch window tool to assess the TESS mission constraints. To understand the long-term dynamics of such a resonant orbit in the Earth-Moon system we employed Dynamical Systems Theory in the Circular Restricted 3-Body Problem (CR3BP). For precise trajectory analysis we use a high-fidelity model and multiple shooting in the General Mission Analysis Tool (GMAT) to optimize the maneuver delta-V and meet mission constraints. Finally we describe how the techniques we have developed can be applied to missions with similar requirements.

  16. MILP-Based 4D Trajectory Planning for Tactical Trajectory Management, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences proposes to develop specialized algorithms and software decision-aiding tools for four-dimensional (4D) vehicle-centric, tactical trajectory...

  17. Trajectory Design to Benefit Trajectory-Based Surface Operations, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Trajectory-based operations constitute a key mechanism considered by the Joint Planning and Development Office (JPDO) for managing traffic in high-density or...

  18. Trajectory Design to Benefit Trajectory-Based Surface Operations, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Trajectory-based operations constitute a key mechanism considered by the Joint Planning and Development Office (JPDO) for managing traffic in high-density or...

  19. Associations between trajectories of perceived racial discrimination and psychological symptoms among African American adolescents.

    Science.gov (United States)

    Smith-Bynum, Mia A; Lambert, Sharon F; English, Devin; Ialongo, Nicholas S

    2014-11-01

    Many African American adolescents experience racial discrimination, with adverse consequences; however, stability and change in these experiences over time have not been examined. We examined longitudinal patterns of perceived racial discrimination assessed in Grades 7-10 and how these discrimination trajectories related to patterns of change in depressive and anxious symptoms and aggressive behaviors assessed over the same 4-year period. Growth mixture modeling performed on a community epidemiologically defined sample of urban African American adolescents (n = 504) revealed three trajectories of discrimination: increasing, decreasing, and stable low. As predicted, African American boys were more frequent targets for racial discrimination as they aged, and they were more likely to be in the increasing group. The results of parallel process growth mixture modeling revealed that youth in the increasing racial discrimination group were four times more likely to be in an increasing depression trajectory than were youth in the low stable discrimination trajectory. Though youth in the increasing racial discrimination group were nearly twice as likely to be in the high aggression trajectory, results were not statistically significant. These results indicate an association between variation in the growth of perceived racial discrimination and youth behavior and psychological well-being over the adolescent years.

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

    NARCIS (Netherlands)

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

  1. 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

  2. Early Life Growth Predictors of Childhood Adiposity Trajectories and Future Risk for Obesity: Birth to Twenty Cohort.

    Science.gov (United States)

    Munthali, Richard J; Kagura, Juliana; Lombard, Zané; Norris, Shane A

    2017-10-01

    There is growing evidence of variations in adiposity trajectories among individuals, but the influence of early life growth patterns on these trajectories is underresearched in low- and middle-income countries. Therefore, our aim was to examine the association between early life conditional weight gain and childhood adiposity trajectories. We previously identified distinct adiposity trajectories (four for girls and three for boys) in black South African children (boys = 877; girls = 947). The association between the trajectories and early life growth patterns, and future obesity risk was assessed by multivariate linear and multinomial logistic and logistic regressions. Conditional weight gain independent of height was computed for infancy (0-2 years) and early childhood (2-4 years). Conditional weight gain before 5 years of age was significantly associated with early onset of obesity or overweight (excess weight) BMI trajectories in both boys and girls. In girls, greater conditional weight gain in infancy was associated with increased relative risk of being in the early-onset obese to morbid obese trajectory, with relative risk ratios of 2.03 (95% confidence interval: 1.17-3.52) compared to belonging to a BMI trajectory in the normal range. Boys and girls in the early-onset obesity or overweight BMI trajectories were more likely to be overweight or obese in early adulthood. Excessive weight gain in infancy and early childhood, independent of linear growth, predicts childhood and adolescent BMI trajectories toward obesity. These results underscore the importance of early life factors in the development of obesity and other NCDs in later life.

  3. Sensitivity Analysis and Mitigation with Applications to Ballistic and Low-thrust Trajectory Design

    Science.gov (United States)

    Alizadeh, Iman

    The ever increasing desire to expand space mission capabilities within the limited budgets of space industries requires new approaches to the old problem of spacecraft trajectory design. For example, recent initiatives for space exploration involve developing new tools to design low-cost, fail-safe trajectories to visit several potential destinations beyond our celestial neighborhood such as Jupiter's moons, asteroids, etc. Designing and navigating spacecraft trajectories to reach these destinations safely are complex and challenging. In particular, fundamental questions of orbital stability imposed by planetary protection requirements are not easily taken into account by standard optimal control schemes. The event of temporary engine loss or an unexpected missed thrust can indeed quickly lead to impact with planetary bodies or other unrecoverable trajectories. While electric propulsion technology provides superior efficiency compared to chemical engines, the very low-control authority and engine performance degradation can impose higher risk to the mission in strongly perturbed orbital environments. The risk is due to the complex gravitational field and its associated chaotic dynamics which causes large navigation dispersions in a short time if left un-controlled. Moreover, in these situations it can be outside the low-thrust propulsion system capability to correct the spacecraft trajectory in a reasonable time frame. These concerns can lead to complete or partial mission failure or even an infeasible mission concept at the early design stage. The goal of this research is to assess and increase orbital stability of ballistic and low-thrust transfer trajectories in multi-body systems. In particular, novel techniques are presented to characterize sensitivity and improve recovery characteristics of ballistic and low-thrust trajectories in unstable orbital environments. The techniques developed are based on perturbation analysis around ballistic trajectories to

  4. 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

  5. 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 ...

  6. 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…

  7. The impact of group prenatal care on pregnancy and postpartum weight trajectories.

    Science.gov (United States)

    Magriples, Urania; Boynton, Marcella H; Kershaw, Trace S; Lewis, Jessica; Rising, Sharon Schindler; Tobin, Jonathan N; Epel, Elissa; Ickovics, Jeannette R

    2015-11-01

    The objective of the study was to investigate whether group prenatal care (Centering Pregnancy Plus [CP+]) has an impact on pregnancy weight gain and postpartum weight loss trajectories and to determine whether prenatal depression and distress might moderate these trajectories. This was a secondary analysis of a cluster-randomized trial of CP+ in 14 Community Health Centers and hospitals in New York City. Participants were pregnant women aged 14-21 years (n = 984). Medical record review and 4 structured interviews were conducted: in the second and third trimesters and 6 and 12 months postpartum. Longitudinal mixed modeling was utilized to evaluate the weight change trajectories in the control and intervention groups. Prenatal distress and depression were also assessed to examine their impact on weight change. There were no significant differences between the intervention and control groups in baseline demographics. Thirty-five percent of the participants were overweight or obese, and more than 50% had excessive weight gain by Institute of Medicine standards. CP+ was associated with improved weight trajectories compared with controls (P prenatal care gained less weight during pregnancy and lost more weight postpartum. This effect was sustained among women who were categorized as obese based on prepregnancy body mass index (P Prenatal depression and distress were significantly associated with higher antepartum weight gain and postpartum weight retention. Women with the highest levels of depression and prenatal distress exhibited the greatest positive impact of group prenatal care on weight trajectories during pregnancy and through 12 months postpartum. Group prenatal care has a significant impact on weight gain trajectories in pregnancy and postpartum. The intervention also appeared to mitigate the effects of depression and prenatal distress on antepartum weight gain and postpartum weight retention. Targeted efforts are needed during and after pregnancy to improve

  8. Associations between Race and Eating Disorder Symptom Trajectories in Black and White Girls.

    Science.gov (United States)

    Bodell, Lindsay P; Wildes, Jennifer E; Cheng, Yu; Goldschmidt, Andrea B; Keenan, Kate; Hipwell, Alison E; Stepp, Stephanie D

    2018-04-01

    Epidemiological research suggests racial differences in the presentation of eating disorder symptoms. However, no studies have examined associations between race and eating disorder symptom trajectories across youth and adolescence, which is necessary to inform culturally sensitive prevention programs. The purpose of the current study was to examine the trajectories of eating disorder symptoms from childhood to young adulthood and to examine whether race was associated with trajectory group membership. Data were drawn from 2,305 Black and White girls who participated in a community-based longitudinal cohort study (Pittsburgh Girls Study) examining the development of psychopathology. The child and adult versions of the Eating Attitudes Test assessed self-reported eating disorder symptoms at six time points between ages 9 and 21 years. Growth mixture modeling was used to examine developmental trajectories of dieting, bulimia/food preoccupation, and total eating disorder symptom scores. Given potential confounds with race and disordered eating, financial strain (i.e., receiving public assistance) and weight were included as covariates. Four to six distinct developmental patterns were found across eating disorder symptoms, including none, increasing, decreasing, or increasing-decreasing trajectories. Black girls had a greater likelihood of being in the decreasing trajectories for dieting, bulimia/food preoccupation, and total eating disorder symptom scores. White girls were more likely to follow increasing trajectories of dieting and total eating disorder symptom scores compared to Black girls. These results highlight the importance of examining the influence of racial background on eating disorder symptoms and the potential need for differences in the timing and focus of prevention interventions in these groups.

  9. 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.

    2015-01-01

    Objective 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. Method Data were obtained from the Boricua Youth Study, a longitudinal study of 2,491 children and adolescents of Puerto Rican background (three assessments from 2000 to 2004). First, age-specific sensation-seeking levels were characterized. Then, age-adjusted residuals were analyzed using growth mixture models (GMM). Results On average, sensation seeking was stable in childhood (ages 5–10) and increased during adolescence (ages 11–17). Mean scores of sensation seeking were higher in the South Bronx vs. Puerto Rico and among males vs. 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, while 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 vs. Puerto Rico) and gender were predictors of membership in a specific class of sensation-seeking trajectory. Conclusion 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. PMID:26598479

  10. Developmental Growth Trajectories in Understanding of Fraction Magnitude from Fourth through Sixth Grade

    Science.gov (United States)

    Resnick, Ilyse; Jordan, Nancy C.; Hansen, Nicole; Rajan, Vinaya; Rodrigues, Jessica; Siegler, Robert S.; Fuchs, Lynn S.

    2016-01-01

    Development of fraction number line estimation was assessed longitudinally over 5 time points between 4th and 6th grades. Although students showed positive linear growth overall, latent class growth analyses revealed 3 distinct growth trajectory classes: Students who were highly accurate from the start and became even more accurate (n = 154);…

  11. Early Childhood Memory and Attention as Predictors of Academic Growth Trajectories

    Science.gov (United States)

    Stipek, Deborah; Valentino, Rachel A.

    2015-01-01

    Longitudinal data from the children of the National Longitudinal Survey of Youth (NLSY) were used to assess how well measures of short-term and working memory and attention in early childhood predicted longitudinal growth trajectories in mathematics and reading comprehension. Analyses also examined whether changes in memory and attention were more…

  12. Trajectories of Discrimination across Adolescence: Associations with Academic, Psychological, and Behavioral Outcomes

    Science.gov (United States)

    Hughes, Diane; Del Toro, Juan; Harding, Jessica F.; Way, Niobe; Rarick, Jason R. D.

    2016-01-01

    The authors explored trajectories of perceived discrimination over a 6-year period (five assessments in 6th-11th grade) in relation to academic, behavioral, and psychological adjustment in 8th and 11th grades. They distinguished discrimination from adults versus peers in addition to overt versus covert discrimination from peers. The sample…

  13. The Trajectory of Popularity Goal during the Transition to Middle School

    Science.gov (United States)

    Dawes, Molly; Xie, Hongling

    2017-01-01

    The trajectory of early adolescents' popularity goal during the transition to middle school was examined in a diverse sample of 401 students. Popularity goal was assessed at five time points from the spring semester of fifth grade through the spring semester of seventh grade with the transition to middle school occurring between the fifth and…

  14. 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.

  15. 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

  16. Trajectories for Novel and Detailed Traffic Information

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Torp, Kristian

    2012-01-01

    the central metric free-flow speed from trajectories, instead of using point-based measurements such as induction-loops. This free-flow speed is widely used to compute and monitor the congestion level. The paper argues that the actual travel-time is a more accurate metric. The paper suggests a novel approach...... are correctly coordinated, and navigational device manufacturers to advice drivers in real-time on expected behavior of signalized intersections. The main conclusion is that trajectories can provide novel insight into the actual traffic situation that is not possible using existing approaches. Further...... to analyzing individual intersections that enables traffic analysts to compute queue lengths and estimated time to pass an intersection. Finally, the paper uses associative rule mining for evaluating green waves on road stretches. Such information can be used to verify that signalized intersections...

  17. Which Better Predicts Conduct Problems? The Relationship of Trajectories of Conduct Problems with ODD and ADHD Symptoms from Childhood into Adolescence

    Science.gov (United States)

    van Lier, Pol A. C.; van der Ende, Jan; Koot, Hans M.; Verhulst, Frank C.

    2007-01-01

    Background: To assess the co-occurrence in deviant trajectories of parent-rated symptoms of conduct disorder (CD), oppositional defiant disorder (ODD) and attention-deficit/hyperactivity disorder (ADHD) from age 4 to 18 years old in a general population sample of Dutch children. Methods: Developmental trajectories of CD, ODD, and ADHD were…

  18. An Energy-Aware Trajectory Optimization Layer for sUAS

    Science.gov (United States)

    Silva, William A.

    The focus of this work is the implementation of an energy-aware trajectory optimization algorithm that enables small unmanned aircraft systems (sUAS) to operate in unknown, dynamic severe weather environments. The software is designed as a component of an Energy-Aware Dynamic Data Driven Application System (EA-DDDAS) for sUAS. This work addresses the challenges of integrating and executing an online trajectory optimization algorithm during mission operations in the field. Using simplified aircraft kinematics, the energy-aware algorithm enables extraction of kinetic energy from measured winds to optimize thrust use and endurance during flight. The optimization layer, based upon a nonlinear program formulation, extracts energy by exploiting strong wind velocity gradients in the wind field, a process known as dynamic soaring. The trajectory optimization layer extends the energy-aware path planner developed by Wenceslao Shaw-Cortez te{Shaw-cortez2013} to include additional mission configurations, simulations with a 6-DOF model, and validation of the system with flight testing in June 2015 in Lubbock, Texas. The trajectory optimization layer interfaces with several components within the EA-DDDAS to provide an sUAS with optimal flight trajectories in real-time during severe weather. As a result, execution timing, data transfer, and scalability are considered in the design of the software. Severe weather also poses a measure of unpredictability to the system with respect to communication between systems and available data resources during mission operations. A heuristic mission tree with different cost functions and constraints is implemented to provide a level of adaptability to the optimization layer. Simulations and flight experiments are performed to assess the efficacy of the trajectory optimization layer. The results are used to assess the feasibility of flying dynamic soaring trajectories with existing controllers as well as to verify the interconnections between

  19. Sequence trajectory generation for garment handling systems

    OpenAIRE

    Liu, Honghai; Lin, Hua

    2008-01-01

    This paper presents a novel generic approach to the planning strategy of garment handling systems. An assumption is proposed to separate the components of such systems into a component for intelligent gripper techniques and a component for handling planning strategies. Researchers can concentrate on one of the two components first, then merge the two problems together. An algorithm is addressed to generate the trajectory position and a clothes handling sequence of clothes partitions, which ar...

  20. Training trajectories by continuous recurrent multilayer networks.

    Science.gov (United States)

    Leistritz, L; Galicki, M; Witte, H; Kochs, E

    2002-01-01

    This paper addresses the problem of training trajectories by means of continuous recurrent neural networks whose feedforward parts are multilayer perceptrons. Such networks can approximate a general nonlinear dynamic system with arbitrary accuracy. The learning process is transformed into an optimal control framework where the weights are the controls to be determined. A training algorithm based upon a variational formulation of Pontryagin's maximum principle is proposed for such networks. Computer examples demonstrating the efficiency of the given approach are also presented.

  1. 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.

  2. Controlling particle trajectories using oscillating microbubbles

    Science.gov (United States)

    Jalikop, Shreyas; Wang, Cheng; Hilgenfeldt, Sascha

    2010-11-01

    In many applications of microfluidics and biotechnology, such as cytometry and drug delivery, it is vital to manipulate the trajectories of microparticles such as vesicles or cells. On this small scale, inertial or gravitational effects are often too weak to exploit. We propose a mechanism to selectively trap and direct particles based on their size in creeping transport flows (Re1). We employ Rayleigh-Nyborg-Westervelt (RNW) streaming generated by an oscillating microbubble, which in turn generates a streaming flow component around the mobile particles. The result is an attractive interaction that draws the particle closer to the bubble. The impenetrability of the bubble interface destroys time-reversal symmetry and forces the particles onto either narrow trajectory bundles or well-defined closed trajectories, where they are trapped. The effect is dependent on particle size and thus allows for the passive focusing and sorting of selected sizes, on scales much smaller than the geometry of the microfluidic device. The device could eliminate the need for complicated microchannel designs with external magnetic or electric fields in applications such as particle focusing and size-based sorting.

  3. 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

  4. Control system design for UAV trajectory tracking

    Science.gov (United States)

    Wang, Haitao; Gao, Jinyuan

    2006-11-01

    In recent years, because of the emerging requirements for increasing autonomy, the controller of uninhabited air vehicles must be augmented with a very sophisticated autopilot design which is capable of tracking complex and agile maneuvering trajectory. This paper provides a simplified control system framework to solve UAV maneuvering trajectory tracking problem. The flight control system is divided into three subsystems including command generation, transformation and allocation. According to the kinematics equations of the aircraft, flight path angle commands can be generated by desired 3D position from path planning. These commands are transformed to body angular rates through direct nonlinear mapping, which is simpler than common multi-loop method based on time scale separation assumption. Then, by using weighted pseudo-inverse method, the control surface deflections are allocated to follow body angular rates from the previous step. In order to improve the robustness, a nonlinear disturbance observer-based approach is used to compensate the uncertainty of system. A 6DOF nonlinear UAV model is controlled to demonstrate the performance of the trajectory tracking control system. Simulation results show that the control strategy is easy to be realized and the precision of tracking is satisfying.

  5. Trajectories of social isolation in adult survivors of childhood cancer.

    Science.gov (United States)

    Howard, A Fuchsia; Tan de Bibiana, Jason; Smillie, Kirsten; Goddard, Karen; Pritchard, Sheila; Olson, Rob; Kazanjian, Arminee

    2014-03-01

    Long-term childhood cancer survivors may be at increased risk for poor social outcomes as a result of their cancer treatment, as well as physical and psychological health problems. Yet, important challenges, namely social isolation, are not well understood. Moreover, survivors' perspectives of social isolation as well as the ways in which this might evolve through young adulthood have yet to be investigated. The purpose of this research was to describe the trajectories of social isolation experienced by adult survivors of a childhood cancer. Data from 30 in-depth interviews with survivors (9 to 38 years after diagnosis, currently 22 to 43 years of age, 60 % women) were analyzed using qualitative, constant comparative methods. Experiences of social isolation evolved over time as survivors grew through childhood, adolescence and young adulthood. Eleven survivors never experienced social isolation after their cancer treatment, nor to the present day. Social isolation among 19 survivors followed one of three trajectories; (1) diminishing social isolation: it got somewhat better, (2) persistent social isolation: it never got better or (3) delayed social isolation: it hit me later on. Knowledge of when social isolation begins and how it evolves over time for different survivors is an important consideration for the development of interventions that prevent or mitigate this challenge. Assessing and addressing social outcomes, including isolation, might promote comprehensive long-term follow-up care for childhood cancer survivors.

  6. Six years after the wave. Trajectories of posttraumatic stress following a natural disaster.

    Science.gov (United States)

    Johannesson, Kerstin Bergh; Arinell, Hans; Arnberg, Filip K

    2015-12-01

    The characteristics of long-term trajectories of distress after disasters are unclear, since few studies include a comparison group. This study examines trajectories of recovery among survivors in comparison to individuals with indirect exposure. Postal surveys were sent to Swedish tourists, repatriated from the 2004 Indian Ocean tsunami (n=2268), at 1, 3, and 6 years after the tsunami to assess posttraumatic stress (PTS) and poor mental health. Items were used to ascertain high and moderate disaster exposure groups and an indirect exposure comparison group. Long-term PTS trajectories were best characterized by a resilient (72.3%), a severe chronic (4.6%), a moderate chronic (11.2%) and a recovering (11.9%) trajectory. Trajectories reported higher levels of PTS than the comparison group. Exposure severity and bereavement were highly influential risk factors. These findings have implications regarding anticipation of long-term psychological adjustment after natural disasters and need for interventions after a single traumatic event with few secondary stressors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Trajectories of mothers' emotional availability: relations with infant temperament in predicting attachment security.

    Science.gov (United States)

    Kim, Bo-Ram; Chow, Sy-Miin; Bray, Bethany; Teti, Douglas M

    2017-02-01

    The present study examined observations of parenting quality (mothers' emotional availability - EA) during infant bedtimes at 4 points across the infants' first year, assessing relations between levels and trajectories of EA and infant attachment at 12 months and the role of infant temperament in moderating these associations. The sample (N = 128) was predominantly Euro-American (82.5%) and at low socioeconomic risk. Latent growth curve modeling with latent basis coefficients indicated substantial individual differences in initial levels and slopes in EA trajectories across the first year. Both levels of maternal EA and EA trajectories across the first year predicted 12-month infant attachment security. Although maternal EA tended to decrease across the first year in the full sample, EA trajectories that showed a "bounce-back" between 6 and 12 months, suggesting more successful maternal adaptation to an expanding infant developmental repertoire, predicted greater infant security at 12 months. In addition, linkages between latent EA trajectories and 12-month attachment were moderated by 3-month infant temperamental reactivity and regulation. These findings indicate that infant attachment security is sensitive to both static and dynamic aspects of parenting quality across the first year, and that infant temperament can interact with both in predicting infant attachment.

  8. Trajectories of Italian Children's Peer Rejection: Associations with Aggression, Prosocial Behavior, Physical Attractiveness, and Adolescent Adjustment.

    Science.gov (United States)

    Di Giunta, Laura; Pastorelli, Concetta; Thartori, Eriona; Bombi, Anna Silvia; Baumgartner, Emma; Fabes, Richard A; Martin, Carol Lynn; Enders, Craig K

    2017-12-08

    In the present study, the predictors and outcomes associated with the trajectories of peer rejection were examined in a longitudinal sample of Italian children (338 boys, 269 girls) ages 10 to 14 years. Follow-up assessments included 60% of the original sample at age 16-17. Low, medium, and high rejection trajectory groups were identified using growth mixture models. Consistent with previous studies, we found that (a) being less prosocial and more physically aggressive at age 10 was characteristic of those children with the high rejection trajectory; (b) being less attractive was related to higher peer rejection from age 10 to 14; and (c) boys with a high rejection trajectory showed high levels of delinquency and anxiety-depression and low levels of academic aspiration at age 16-17, whereas girls with a high rejection trajectory showed low levels of academic aspiration and social competence at age 16-17. Our findings indicate the detrimental consequences of peer rejection on children's development and adjustment and shed light on the mechanisms that contribute to maintaining or worsening (e.g., being attractive, prosocial, and aggressive) a child's negative status (e.g., being rejected) within his or her peer group over time.

  9. 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.

  10. Periodic trajectories for two-dimensional nonintegrable Hamiltonians

    International Nuclear Information System (INIS)

    Davies, K.T.R.

    1990-02-01

    I want to report on some calculations of classical periodic trajectories in a two-dimensional nonintegrable potential. After a brief introduction, I will present some details of the theory. The main part of this report will be devoted to showing pictures of the various families of trajectories and to discussing the topology (in E-τ space) and branching behavior of these families. Then I will demonstrate the connection between periodic trajectories and ''nearby'' nonperiodic trajectories, which nicely illustrates the relationship of this work to chaos. Finally, I will discuss very briefly how periodic trajectories can be used to calculate tori. 12 refs., 40 figs

  11. 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.

  12. 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

  13. Development of an Integrated Intelligent Multi -Objective Framework for UAV Trajectory Generation

    Science.gov (United States)

    Wilburn, Jennifer Nicole

    This thesis explores a variety of path planning and trajectory generation schemes intended for small, fixed-wing Unmanned Aerial Vehicles. Throughout this analysis, discrete and pose-based methods are investigated. Pose-based methods are the focus of this research due to their increased flexibility and typically lower computational overhead. Path planning in 3 dimensions is also performed. The 3D Dubins methodology presented is an extension of a previously suggested approach and addresses both the mathematical formulation of the methodology, as well as an assessment of numerical issues encountered and the solutions implemented for these. The main contribution of this thesis is a 3-dimensional clothoid trajectory generation algorithm, which produces flyable paths of continuous curvature to ensure a more followable commanded path. This methodology is an extension of the 3D Dubins method and the 2D clothoid method, which have been implemented herein. To ensure flyability of trajectories produced by 3D pose-based trajectory generation methodologies, a set of criteria are specified to limit the possible solutions to only those flyable by the aircraft. Additionally, several assumptions are made concerning the motion of the aircraft in order to simplify the path generation problem. The 2D and 3D clothoid and Dubins trajectory planners are demonstrated through a trajectory tracking performance comparison between first the 2D Dubins and 2D clothoid methods using a position proportional-integral-derivative controller, then the 3D Dubins and 3D clothoid methods using both a position proportional-integral-derivative controller and an outer-loop non-linear dynamic inversion controller, within the WVU UAV Simulation Environment. These comparisons are demonstrated for both nominal and off-nominal conditions, and show that for both 2D and 3D implementations, the clothoid path planners yields paths with better trajectory tracking performance as compared to the Dubins path planners

  14. The ESA's Space Trajectory Analysis software suite

    Science.gov (United States)

    Ortega, Guillermo

    The European Space Agency (ESA) initiated in 2005 an internal activity to develop an open source software suite involving university science departments and research institutions all over the world. This project is called the "Space Trajectory Analysis" or STA. This article describes the birth of STA and its present configuration. One of the STA aims is to promote the exchange of technical ideas, and raise knowledge and competence in the areas of applied mathematics, space engineering, and informatics at University level. Conceived as a research and education tool to support the analysis phase of a space mission, STA is able to visualize a wide range of space trajectories. These include among others ascent, re-entry, descent and landing trajectories, orbits around planets and moons, interplanetary trajectories, rendezvous trajectories, etc. The article explains that STA project is an original idea of the Technical Directorate of ESA. It was born in August 2005 to provide a framework in astrodynamics research at University level. As research and education software applicable to Academia, a number of Universities support this development by joining ESA in leading the development. ESA and Universities partnership are expressed in the STA Steering Board. Together with ESA, each University has a chair in the board whose tasks are develop, control, promote, maintain, and expand the software suite. The article describes that STA provides calculations in the fields of spacecraft tracking, attitude analysis, coverage and visibility analysis, orbit determination, position and velocity of solar system bodies, etc. STA implements the concept of "space scenario" composed of Solar system bodies, spacecraft, ground stations, pads, etc. It is able to propagate the orbit of a spacecraft where orbital propagators are included. STA is able to compute communication links between objects of a scenario (coverage, line of sight), and to represent the trajectory computations and

  15. 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.

  16. Lagrangian Trajectory Modeling of Lunar Dust Particles

    Science.gov (United States)

    Lane, John E.; Metzger, Philip T.; Immer, Christopher D.

    2008-01-01

    Apollo landing videos shot from inside the right LEM window, provide a quantitative measure of the characteristics and dynamics of the ejecta spray of lunar regolith particles beneath the Lander during the final 10 [m] or so of descent. Photogrammetry analysis gives an estimate of the thickness of the dust layer and angle of trajectory. In addition, Apollo landing video analysis divulges valuable information on the regolith ejecta interactions with lunar surface topography. For example, dense dust streaks are seen to originate at the outer rims of craters within a critical radius of the Lander during descent. The primary intent of this work was to develop a mathematical model and software implementation for the trajectory simulation of lunar dust particles acted on by gas jets originating from the nozzle of a lunar Lander, where the particle sizes typically range from 10 micron to 500 micron. The high temperature, supersonic jet of gas that is exhausted from a rocket engine can propel dust, soil, gravel, as well as small rocks to high velocities. The lunar vacuum allows ejected particles to travel great distances unimpeded, and in the case of smaller particles, escape velocities may be reached. The particle size distributions and kinetic energies of ejected particles can lead to damage to the landing spacecraft or to other hardware that has previously been deployed in the vicinity. Thus the primary motivation behind this work is to seek a better understanding for the purpose of modeling and predicting the behavior of regolith dust particle trajectories during powered rocket descent and ascent.

  17. Population assessment of future trajectories in coronary heart disease mortality.

    Directory of Open Access Journals (Sweden)

    Rosa Björk Thorolfsdottir

    Full Text Available BACKGROUND: Coronary heart disease (CHD mortality rates have been decreasing in Iceland since the 1980s, largely reflecting improvements in cardiovascular risk factors. The purpose of this study was to predict future CHD mortality in Iceland based on potential risk factor trends. METHODS AND FINDINGS: The previously validated IMPACT model was used to predict changes in CHD mortality between 2010 and 2040 among the projected population of Iceland aged 25-74. Calculations were based on combining: i data on population numbers and projections (Statistics Iceland, ii population risk factor levels and projections (Refine Reykjavik study, and iii effectiveness of specific risk factor reductions (published meta-analyses. Projections for three contrasting scenarios were compared: (1 If the historical risk factor trends of past 30 years were to continue, the declining death rates of past decades would level off, reflecting population ageing. (2 If recent trends in risk factors (past 5 years continue, this would result in a death rate increasing from 49 to 70 per 100,000. This would reflect a recent plateau in previously falling cholesterol levels and recent rapid increases in obesity and diabetes prevalence. 3 Assuming that in 2040 the entire population enjoys optimal risk factor levels observed in low risk cohorts, this would prevent almost all premature CHD deaths before 2040. CONCLUSIONS: The potential increase in CHD deaths with recent trends in risk factor levels is alarming both for Iceland and probably for comparable Western populations. However, our results show considerable room for reducing CHD mortality. Achieving the best case scenario could eradicate premature CHD deaths by 2040. Public health policy interventions based on these predictions may provide a cost effective means of reducing CHD mortality in the future.

  18. Meteor trajectory estimation from radio meteor observations

    Science.gov (United States)

    Kákona, J.

    2016-01-01

    Radio meteor observation techniques are generally accepted as meteor counting methods useful mainly for meteor flux detection. Due to the technical progress in radio engineering and electronics a construction of a radio meteor detection network with software defined receivers has become possible. These receivers could be precisely time synchronized and could obtain data which provide us with more information than just the meteor count. We present a technique which is able to compute a meteor trajectory from the data recorded by multiple radio stations.

  19. 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

  20. Data Wrangling Within Different Astronomy Career Trajectories

    Science.gov (United States)

    Guillen, Reynal; Gu, D.; Holbrook, J.; Murillo, L.; Traweek, S.

    2012-01-01

    Five kinds of astronomers work with large data sets: cosmologists, data analysts, instrumentation people, observers, and numerical theorists. Each of these career trajectories can diverge and converge in and out of collaborations with each other and perform different kinds of work. Nonetheless, each group defines and wrangles data differently. This poster characterizes their different meanings of data, analytic skills, techniques, and technologies. It also identifies some sites and patterns of convergence. We plot these collaborative relationships in bi-partite graphs. These emergent characteristics of the astronomy workforce have implications for curricula, pedagogies, and the division of labor in research collaborations.

  1. Design of Quiet Rotorcraft Approach Trajectories

    Science.gov (United States)

    Padula, Sharon L.; Burley, Casey L.; Boyd, D. Douglas, Jr.; Marcolini, Michael A.

    2009-01-01

    A optimization procedure for identifying quiet rotorcraft approach trajectories is proposed and demonstrated. The procedure employs a multi-objective genetic algorithm in order to reduce noise and create approach paths that will be acceptable to pilots and passengers. The concept is demonstrated by application to two different helicopters. The optimized paths are compared with one another and to a standard 6-deg approach path. The two demonstration cases validate the optimization procedure but highlight the need for improved noise prediction techniques and for additional rotorcraft acoustic data sets.

  2. Beam trajectories through the upgraded XTU tandem

    International Nuclear Information System (INIS)

    Guan Xialing

    1988-01-01

    The paper deals with a problem applicable to all electrostatic accelerators with inclined field accelerating tubes, how the trajectory of the central beam particle is affected if one of the accelerating gaps must be shorted out due to insulator failure. For the long tube of the Legnaro XTU tandem the effect of each accelerator gap is calculated and a method of compensation either by shorting out an appropriate gap with reversed incline or by appropriately steering the beam into the entrance of the low energy tube is given. (orig.)

  3. Quadrotor trajectory tracking using PID cascade control

    Science.gov (United States)

    Idres, M.; Mustapha, O.; Okasha, M.

    2017-12-01

    Quadrotors have been applied to collect information for traffic, weather monitoring, surveillance and aerial photography. In order to accomplish their mission, quadrotors have to follow specific trajectories. This paper presents proportional-integral-derivative (PID) cascade control of a quadrotor for path tracking problem when velocity and acceleration are small. It is based on near hover controller for small attitude angles. The integral of time-weighted absolute error (ITAE) criterion is used to determine the PID gains as a function of quadrotor modeling parameters. The controller is evaluated in three-dimensional environment in Simulink. Overall, the tracking performance is found to be excellent for small velocity condition.

  4. Religion and psychosis: a common evolutionary trajectory?

    Science.gov (United States)

    Dein, Simon; Littlewood, Roland

    2011-07-01

    In this article we propose that schizophrenia and religious cognition engage cognate mental modules in the over-attribution of agency and the overextension of theory of mind. We argue similarities and differences between assumptions of ultrahuman agents with omniscient minds and certain ''pathological'' forms of thinking in schizophrenia: thought insertion, withdrawal and broadcasting, and delusions of reference. In everyday religious cognition agency detection and theory of mind modules function ''normally,'' whereas in schizophrenia both modules are impaired. It is suggested that religion and schizophrenia have perhaps had a related evolutionary trajectory.

  5. 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

    Exploration Mission 1 (EM-1) will be the first mission to send an uncrewed Orion Multi-Purpose Crew Vehicle (MPCV) to cislunar space in the fall of 2019. EM-1 was originally conceived as a lunar free-return mission, but was later changed to a Distant Retrograde Orbit (DRO) mission as a precursor to the Asteroid Redirect Mission. To understand the required mission performance (i.e., propellant requirement), a series of trajectory optimization runs was conducted using JSC's Copernicus spacecraft trajectory optimization tool. In order for the runs to be done in a timely manner, it was necessary to employ a parallelization approach on a computing cluster using a new trajectory scan tool written in Python. Details of the scan tool are provided and how it is used to perform the scans and post-process the results. Initially, a scan of daily due east launched EM-1 DRO missions in 2018 was made. Valid mission opportunities are ones that do not exceed the useable propellant available to perform the required burns. The initial scan data showed the propellant and delta-V performance patterns for each launch period. As questions were raised from different subsystems (e.g., power, thermal, communications, flight operations, etc.), the mission parameters or data that were of interest to them were added to the scan output data file. The additional data includes: (1) local launch and landing times in relation to sunrise and sunset, (2) length of eclipse periods during the in-space portion of the mission, (3) Earth line of sight from cislunar space, (4) Deep Space Network field of view looking towards cislunar space, and (5) variation of the downrange distance from Earth entry interface to splashdown. Mission design trades can also be performed based on the information that the additional data shows. For example, if the landing is in darkness, but the recovery operations team desires a landing in daylight, then an analysis is performed to determine how to change the mission design

  6. 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....

  7. 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.

  8. 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.

  9. 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

  10. Trajectories of maternal weight from before pregnancy through postpartum and associations with childhood obesity.

    Science.gov (United States)

    Leonard, Stephanie A; Rasmussen, Kathleen M; King, Janet C; Abrams, Barbara

    2017-11-01

    Background: Prepregnancy body mass index [BMI (in kg/m 2 )], gestational weight gain, and postpartum weight retention may have distinct effects on the development of child obesity, but their combined effect is currently unknown. Objective: We described longitudinal trajectories of maternal weight from before pregnancy through the postpartum period and assessed the relations between maternal weight trajectories and offspring obesity in childhood. Design: We analyzed data from 4436 pairs of mothers and their children in the National Longitudinal Survey of Youth 1979 (1981-2014). We used latent-class growth modeling in addition to national recommendations for prepregnancy BMI, gestational weight gain, and postpartum weight retention to create maternal weight trajectory groups. We used modified Poisson regression models to assess the associations between maternal weight trajectory group and offspring obesity at 3 age periods (2-5, 6-11, and 12-19 y). Results: Our analysis using maternal weight trajectories based on either latent-class results or recommendations showed that the risk of child obesity was lowest in the lowest maternal weight trajectory group. The differences in obesity risk were largest after 5 y of age and persisted into adolescence. In the latent-class analysis, the highest-order maternal weight trajectory group consisted almost entirely of women who were obese before pregnancy and was associated with a >2-fold increase in the risk of offspring obesity at ages 6-11 y (adjusted RR: 2.39; 95% CI: 1.97, 2.89) and 12-19 y (adjusted RR: 2.74; 95% CI: 2.13, 3.52). In the analysis with maternal weight trajectory groups based on recommendations, the risk of child obesity was consistently highest for women who were overweight or obese at the beginning of pregnancy. Conclusion: These findings suggest that high maternal weight across the childbearing period increases the risk of obesity in offspring during childhood, but high prepregnancy BMI has a stronger

  11. Dietary Fiber Intake in Relation to Knee Pain Trajectory.

    Science.gov (United States)

    Dai, Zhaoli; Lu, Na; Niu, Jingbo; Felson, David T; Zhang, Yuqing

    2017-09-01

    Dietary fiber may reduce knee pain, in part by lowering body weight and reducing inflammation. In this study, we assessed whether fiber intake was associated with patterns of knee pain development. In a prospective, multicenter cohort of 4,796 men and women ages 45-79 years with or at risk of knee osteoarthritis, participants underwent annual followups for 8 years. Dietary fiber intake was estimated using a validated food frequency questionnaire at baseline. Group-based trajectory modeling was used to identify Western Ontario and McMaster Universities Osteoarthritis Index pain trajectories, which were assessed for associations with dietary fiber intake using polytomous regression models. Of the eligible participants (4,470 persons and 8,940 knees, mean ± SD age 61.3 ± 9.1 years, 58% women), 4.9% underwent knee replacement and were censored at the time of surgery. Four distinct knee pain patterns were identified: no pain (34.5%), mild pain (38.1%), moderate pain (21.2%), and severe pain (6.2%). Dietary total fiber was inversely related to membership in the moderate or severe pain groups (P ≤ 0.006 for trend for both). Subjects in the highest versus those in the lowest quartile of total fiber intake had a lower risk of belonging to the moderate pain pattern group (odds ratio [OR] 0.76 [95% confidence interval (95% CI) 0.61-0.93]) and severe pain pattern group (OR 0.56 [95% CI 0.41-0.78]). Similar results were found with grain fiber and these 2 pain pattern groups. Our findings suggest that a high intake of dietary total or grain fiber, particularly the recommended daily fiber average intake of 25 gm per day, is associated with a lower risk of developing moderate or severe knee pain over time. © 2016, American College of Rheumatology.

  12. Mini-Mental State Examination score trajectories and incident disabling dementia among community-dwelling older Japanese adults.

    Science.gov (United States)

    Taniguchi, Yu; Kitamura, Akihiko; Murayama, Hiroshi; Amano, Hidenori; Shinozaki, Tomohiro; Yokota, Isao; Seino, Satoshi; Nofuji, Yu; Nishi, Mariko; Yokoyama, Yuri; Matsuyama, Yutaka; Fujiwara, Yoshinori; Shinkai, Shoji

    2017-11-01

    The present prospective study used repeated measures analysis to identify potential Mini-Mental State Examination (MMSE) score trajectories and determine whether MMSE trajectory was associated with incident disabling dementia among community-dwelling older Japanese adults. A total of 1724 non-demented adults (mean age 71.4 years [SD 5.7]; 56.7% women) aged 65-90 years participated in annual geriatric health assessments during the period from June 2002 through July 2014. The total number of observations was 6755, and the average number of follow-up assessments was 3.9. A review of municipal databases in the Japanese public long-term care insurance system showed that 205 (11.9%) participants developed disabling dementia through December 2014. We identified three distinct MMSE score trajectory patterns (high, middle and low) in adults aged 65-90 years. After adjusting for important confounders, participants with middle (42.8%) and low (5.1%) MMSE trajectories had hazard ratios of 2.46 (95% confidence interval 1.64-3.68) and 10.73 (95% confidence interval 4.91-23.45), respectively, for incident disabling dementia, as compared with those in the high (52.1%) trajectory group. Approximately half of the participants were classified as having a high MMSE trajectory, whereas 43% and 5% had middle and low MMSE trajectories, respectively, in this population. Individuals with middle and low MMSE trajectories had a higher risk for incident disabling dementia, which suggests that a high-risk approach to dementia prevention should target people with mild and more rapid cognitive decline. Geriatr Gerontol Int 2017; 17: 1928-1935. © 2017 Japan Geriatrics Society.

  13. 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.

  14. Parenting Styles and Body Mass Index Trajectories From Adolescence to Adulthood

    Science.gov (United States)

    Fuemmeler, Bernard F.; Yang, Chongming; Costanzo, Phil; Hoyle, Rick H.; Ph.D.; Siegler, Ilene C.; Williams, Redford B.; Østbye, Truls

    2013-01-01

    Objective Parenting styles such as authoritarian, disengaged, or permissive are thought to be associated with greater adolescent obesity risk than an authoritative style. This study assessed the relationship between parenting styles and changes in body mass index (BMI) from adolescence to young adulthood. Methods The study included self-reported data from adolescents in the National Longitudinal Study of Adolescent Health. Factor mixture modeling, a data-driven approach, was used to classify participants into parenting style groups based on measures of acceptance and control. Latent growth modeling (LGM) identified patterns of developmental changes in BMI. After a number of potential cofounders were controlled for, parenting style variables were entered as predictors of BMI trajectories. Analyses were also conducted for males and females of three racial/ethnic groups (Hispanic, black, white) to assess whether parenting styles were differentially associated with BMI trajectories in these 6 groups. Results Parenting styles were classified into 4 groups: authoritarian, disengaged, permissive, and balanced. Compared with the balanced parenting style, authoritarian and disengaged parenting styles were associated with a less steep average BMI increase (linear slope) over time, but also less leveling off (quadratic) of BMI over time. Differences in BMI trajectories were observed for various genders and races, but the differences did not reach statistical significance. Conclusions Adolescents who reported having parents with authoritarian or disengaged parenting styles had greater increases in BMI as they transitioned to young adulthood despite having a lower BMI trajectory through adolescence. PMID:22545979

  15. Parenting styles and body mass index trajectories from adolescence to adulthood.

    Science.gov (United States)

    Fuemmeler, Bernard F; Yang, Chongming; Costanzo, Phil; Hoyle, Rick H; Siegler, Ilene C; Williams, Redford B; Ostbye, Truls

    2012-07-01

    Parenting styles such as authoritarian, disengaged, or permissive are thought to be associated with greater adolescent obesity risk than an authoritative style. This study assessed the relationship between parenting styles and changes in body mass index (BMI) from adolescence to young adulthood. The study included self-reported data from adolescents in the National Longitudinal Study of Adolescent Health. Factor mixture modeling, a data-driven approach, was used to classify participants into parenting style groups based on measures of acceptance and control. Latent growth modeling (LGM) identified patterns of developmental changes in BMI. After a number of potential confounders were controlled for, parenting style variables were entered as predictors of BMI trajectories. Analyses were also conducted for male and female individuals of 3 racial-ethnic groups (Hispanic, black, white) to assess whether parenting styles were differentially associated with BMI trajectories in these 6 groups. Parenting styles were classified into 4 groups: authoritarian, disengaged, permissive, and balanced. Compared with the balanced parenting style, authoritarian and disengaged parenting styles were associated with a less steep average BMI increase (linear slope) over time, but also less leveling off (quadratic) of BMI over time. Differences in BMI trajectories were observed for various genders and races, but the differences did not reach statistical significance. Adolescents who reported having parents with authoritarian or disengaged parenting styles had greater increases in BMI as they transitioned to young adulthood despite having a lower BMI trajectory through adolescence.

  16. Trajectories of Identity Formation Modes and Their Personality Context in Adolescence.

    Science.gov (United States)

    Topolewska-Siedzik, Ewa; Cieciuch, Jan

    2018-04-01

    Identity formation is a dynamic process during adolescence. Trajectories of identity formation were assessed longitudinally in early and middle adolescents, taking into account the personality underpinnings of this process. Identity formation was conceptualized according to the circumplex of identity formation modes. The model distinguishes basic modes rooted in Marcia's categories of exploration and commitment. Plasticity and stability, the two higher order Big Five meta-traits, were used to assess personality underpinnings. This study includes five measurement waves over 1.5 years and involves 1,839 Polish participants; 914 early adolescents (53.9% girls) and 925 middle adolescents (63.8% girls). The results suggest that (1) the four identity formation modes change dynamically, showing linear and curvilinear growth and that (2) identity formation mode trajectories are more dynamic in middle adolescence than in early adolescence. The results also showed that, in the conditional model, (3) the higher-order personality factors and gender affect the growth factors of identity formation modes. Overall, trajectories of identity formation modes are more linear during early adolescence and more curvilinear during middle adolescence. The initial levels in identity trajectories are influenced by the personality metatraits but only plasticity is related to change among early adolescents.

  17. 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.

  18. Trajectories of Mexican American and mainstream cultural values among Mexican American adolescents.

    Science.gov (United States)

    Knight, George P; Basilio, Camille D; Cham, Heining; Gonzales, Nancy A; Liu, Yu; Umaña-Taylor, Adriana J

    2014-12-01

    Mexican Americans are one of the largest and fastest growing ethnic groups in the United States, yet we have limited knowledge regarding changes (i.e., developmental trajectories) in cultural orientation based upon their exposure to the Mexican American and mainstream cultures. We examined the parallel trajectories of Mexican American and mainstream cultural values in a sample of 749 Mexican American adolescents (49 % female) across assessments during the fifth grade (approximately 11 years of age), the seventh grade (approximately 13 years of age) and the tenth grade (approximately 16 years of age). We expected that these values would change over this developmental period and this longitudinal approach is more appropriate than the often used median split classification to identify distinct types of acculturation. We found four distinct acculturation trajectory groups: two trajectory groups that were increasing slightly with age in the endorsement of mainstream cultural values, one of which was relatively stable in Mexican American cultural values while the other was declining in their endorsement of these values; and two trajectory groups that were declining substantially with age in their endorsement of mainstream cultural values, one of which was also declining in Mexican American cultural values and the other which was stable in these values. These four trajectory groups differed in expected ways on a number of theoretically related cultural variables, but were not highly consistent with the median split classifications. The findings highlight the need to utilize longitudinal data to examine the developmental changes of Mexican American individual's adaptation to the ethnic and mainstream culture in order to understand more fully the processes of acculturation and enculturation.

  19. Longitudinal Trajectories of Suicidal Ideation and Subsequent Suicide Attempts among Adolescent Inpatients

    Science.gov (United States)

    Czyz, E.K.; King, C.A.

    2013-01-01

    Objective A period of particularly high risk for suicide attempts among adolescent inpatients is within 12 months after discharge. However, little is known about longitudinal trajectories of suicidal ideation in this high-risk group and how these relate to post-hospitalization suicide attempts and rehospitalizations. Our objectives were to identify these trajectories and examine their relationships with post-hospitalization psychiatric crises. We also examined predictors of trajectory group membership. Method Participants (N=376; ages 13-17; 72% females) were assessed at hospitalization and 3, 6, and 12 months later. Trajectory groups, and their predictors, were identified with latent class growth modeling. We used logistic regression to examine associations between trajectory groups and likelihood of suicide attempts and rehospitalization, controlling for attempt history. Results Three trajectory groups were identified: (1) subclinical ideators (31.6%); (2) elevated ideators with rapidly declining ideation (57.4%); and (3) chronically elevated ideators (10.9%). Adolescents in the chronically elevated ideation group had 2.29[(CI=1.08,4.85), p=0.03] and 4.15[(CI=1.65,10.44), psuicide and 3.23[(CI=1.37,7.69), p=0.01] and 11.20[(CI=4.33,29.01), psuicidal ideation. Conclusions Results suggest that suicidal ideation severity at hospitalization may not be an adequate marker for subsequent suicidal crises. It is important to identify adolescents vulnerable to persisting suicidal ideation, as they are at highest risk of psychiatric crises. Addressing hopelessness may facilitate faster declines in ideation after hospitalization. Results also highlight a need for consistent monitoring of these adolescents' suicidal ideation after discharge. PMID:24079705

  20. Interpersonal Callousness from Childhood to Adolescence: Developmental Trajectories and Early Risk Factors.

    Science.gov (United States)

    Byrd, Amy L; Hawes, Samuel W; Loeber, Rolf; Pardini, Dustin A

    2018-01-01

    Youth with a callous interpersonal style, consistent with features of adult psychopathy (e.g., lack of guilt, deceitful), are at risk for exhibiting severe and protracted antisocial behaviors. However, no studies have examined changes that occur in interpersonal callousness (IC) from childhood to adolescence, and little is known about the influence of early child, social, and contextual factors on trajectories of IC. The current study examined distinct patterns of IC across childhood and adolescence and associations with early risk factors. Participants were an at-risk sample of 503 boys (56% African American) assessed annually from around ages 7-15. Analyses examined child (anger dysregulation, fearfulness), social (peer, family, maltreatment), and contextual (psychosocial adversity) factors associated with teacher-reported IC trajectories across childhood and adolescence. Using latent class growth analysis, five trajectories of IC were identified (early-onset chronic, childhood-limited, adolescent-onset, moderate, low). Approximately 10% of boys followed an early-onset chronic trajectory, and a roughly equal percent of youth followed childhood-limited trajectory (10%) or an adolescent-onset trajectory (12%) of IC across development. Specifically, half of the boys with high IC in childhood did not continue to exhibit significant levels of these features into adolescence, whereas an equal proportion of youth with low IC in childhood demonstrated increasing levels during the transition to adolescence. Boys in the early-onset chronic group were characterized by the most risk factors and were differentiated from those with childhood-limited and adolescent-onset IC only by higher conduct problems, fearlessness, and emotional abuse/neglect. Findings are discussed in terms of developmental models of IC and several avenues for early targeted interventions.

  1. 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…

  2. Trajectory averaging for stochastic approximation MCMC algorithms

    KAUST Repository

    Liang, Faming

    2010-10-01

    The subject of stochastic approximation was founded by Robbins and Monro [Ann. Math. Statist. 22 (1951) 400-407]. After five decades of continual development, it has developed into an important area in systems control and optimization, and it has also served as a prototype for the development of adaptive algorithms for on-line estimation and control of stochastic systems. Recently, it has been used in statistics with Markov chain Monte Carlo for solving maximum likelihood estimation problems and for general simulation and optimizations. In this paper, we first show that the trajectory averaging estimator is asymptotically efficient for the stochastic approximation MCMC (SAMCMC) algorithm under mild conditions, and then apply this result to the stochastic approximation Monte Carlo algorithm [Liang, Liu and Carroll J. Amer. Statist. Assoc. 102 (2007) 305-320]. The application of the trajectory averaging estimator to other stochastic approximationMCMC algorithms, for example, a stochastic approximation MLE algorithm for missing data problems, is also considered in the paper. © Institute of Mathematical Statistics, 2010.

  3. Experimental nonlocal steering of Bohmian trajectories.

    Science.gov (United States)

    Xiao, Ya; Kedem, Yaron; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

    2017-06-26

    Interpretations of quantum mechanics (QM), or proposals for underlying theories, that attempt to present a definite realist picture, such as Bohmian mechanics, require strong non-local effects. Naively, these effects would violate causality and contradict special relativity. However if the theory agrees with QM the violation cannot be observed directly. Here, we demonstrate experimentally such an effect: we steer the velocity and trajectory of a Bohmian particle using a remote measurement. We use a pair of photons and entangle the spatial transverse position of one with the polarization of the other. The first photon is sent to a double-slit-like apparatus, where its trajectory is measured using the technique of Weak Measurements. The other photon is projected to a linear polarization state. The choice of polarization state, and the result, steer the first photon in the most intuitive sense of the word. The effect is indeed shown to be dramatic, while being easy to visualize. We discuss its strength and what are the conditions for it to occur.

  4. Cosmic ray particle dosimetry and trajectory tracing

    International Nuclear Information System (INIS)

    Cruty, M.R.; Benton, E.V.; Turnbill, C.E.; Philpott, D.E.

    1975-01-01

    Five pocket mice (Perognathus longimembris) were flown on Apollo XVII, each with a solid-state (plastic) nuclear track detector implanted beneath its scalp. The subscalp detectors were sensitive to HZE cosmic ray particles with a LET greater than or approximately equal to 0.15 million electron volts per micrometer (MeV/micron). A critical aspect of the dosimetry of the experiment involved tracing individual particle trajectories through each mouse head from particle tracks registered in the individual subscalp detectors, thereby establishing a one-to-one correspondence between a trajectory location in the tissue and the presence or absence of a lesion. The other major aspect was the identification of each registered particle. An average of 16 particles with Z greater than or equal to 6 and 2.2 particles with Z greater than or equal to 20 were found per detector. The track density, 29 tracks/sq cm, when adjusted for detection volume, was in agreement with the photographic emulsion data from an area dosimeter located next to the flight package

  5. 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.

  6. 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.

  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. 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

  9. 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

  10. Measuring the Distance of Moving Objects from Big Trajectory Data

    Directory of Open Access Journals (Sweden)

    Khaing Phyo Wai

    2017-03-01

    Full Text Available Location-based services have become important in social networking, mobile applications, advertising, traffic monitoring, and many other domains. The growth of location sensing devices has led to the vast generation of dynamic spatial-temporal data in the form of moving object trajectories which can be characterized as big trajectory data. Big trajectory data enables the opportunities such as analyzing the groups of moving objects. To obtain such facilities, the issue of this work is to find a distance measurement method that respects the geographic distance and the semantic similarity for each trajectory. Measurement of similarity between moving objects is a difficult task because not only their position changes but also their semantic features vary. In this research, a method to measure trajectory similarity based on both geographical features and semantic features of motion is proposed. Finally, the proposed methods are practically evaluated by using real trajectory dataset.

  11. A Formally Verified Conflict Detection Algorithm for Polynomial Trajectories

    Science.gov (United States)

    Narkawicz, Anthony; Munoz, Cesar

    2015-01-01

    In air traffic management, conflict detection algorithms are used to determine whether or not aircraft are predicted to lose horizontal and vertical separation minima within a time interval assuming a trajectory model. In the case of linear trajectories, conflict detection algorithms have been proposed that are both sound, i.e., they detect all conflicts, and complete, i.e., they do not present false alarms. In general, for arbitrary nonlinear trajectory models, it is possible to define detection algorithms that are either sound or complete, but not both. This paper considers the case of nonlinear aircraft trajectory models based on polynomial functions. In particular, it proposes a conflict detection algorithm that precisely determines whether, given a lookahead time, two aircraft flying polynomial trajectories are in conflict. That is, it has been formally verified that, assuming that the aircraft trajectories are modeled as polynomial functions, the proposed algorithm is both sound and complete.

  12. 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 ...

  13. 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...

  14. 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 ...

  15. 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.

  16. Algorithms for computing efficient, electric-propulsion, spiralling trajectories

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop techniques for rapidly designing many-revolution, electric-propulsion, spiralling trajectories, including the effects of shadowing, gravity harmonics, and...

  17. A Dropsonde Glider with Adaptive Trajectory Planning, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Dropsondes are one of the primary atmospheric measurement tools available to researchers. Current dropsondes are deployed with a free fall parachute trajectory,...

  18. Towards a Formal Semantics of Flight Plans and Trajectories

    Science.gov (United States)

    Hagen, George E.; Butler, Ricky W.

    2014-01-01

    In the National Airspace System, ight plans are often used only as a planning tool by air trac controllers and aircraft operators. These plans are implicitly translated into trajectories by the pilot or by the ight management system, and subsequently own by the aircraft. This translation process inevitably introduces di erences between the plan and the trajectory. However, given the current intended usage, exact correspondence between the plan and the trajectory is not needed. To achieve greater capacity and eciency, future air trac management concepts are being designed around the use of trajectories where predictability is extremely important. In this paper, a mathematical relationship between ight plans and trajectories is explored with the goal of making feasible, highly accurate predictions of future positions and velocities of aircraft. The goal here is to describe, in mathematically precise detail, a formal language of trajectories, whereby all receivers of the trajectory information will be able to arrive at precisely the same trajectory predication and to do this without having aircraft broadcast a large amount of data. Although even a four-dimensional ight plan is simple in structure, this paper will show that it is inherently ambiguous and will explore these issues in detail. In e ect, we propose that a rigorous semantics for ight plans can be developed and this will serve as an important stepping stone towards trajectory-based operations in the National Airspace System.

  19. Pairwise Trajectory Management (PTM): Concept Description and Documentation

    Science.gov (United States)

    Jones, Kenneth M.; Graff, Thomas J.; Carreno, Victor; Chartrand, Ryan C.; Kibler, Jennifer L.

    2018-01-01

    Pairwise Trajectory Management (PTM) is an Interval Management (IM) concept that utilizes airborne and ground-based capabilities to enable the implementation of airborne pairwise spacing capabilities in oceanic regions. The goal of PTM is to use airborne surveillance and tools to manage an "at or greater than" inter-aircraft spacing. Due to the accuracy of Automatic Dependent Surveillance-Broadcast (ADS-B) information and the use of airborne spacing guidance, the minimum PTM spacing distance will be less than distances a controller can support with current automation systems that support oceanic operations. Ground tools assist the controller in evaluating the traffic picture and determining appropriate PTM clearances to be issued. Avionics systems provide guidance information that allows the flight crew to conform to the PTM clearance issued by the controller. The combination of a reduced minimum distance and airborne spacing management will increase the capacity and efficiency of aircraft operations at a given altitude or volume of airspace. This document provides an overview of the proposed application, a description of several key scenarios, a high level discussion of expected air and ground equipment and procedure changes, a description of a NASA human-machine interface (HMI) prototype for the flight crew that would support PTM operations, and initial benefits analysis results. Additionally, included as appendices, are the following documents: the PTM Operational Services and Environment Definition (OSED) document and a companion "Future Considerations for the Pairwise Trajectory Management (PTM) Concept: Potential Future Updates for the PTM OSED" paper, a detailed description of the PTM algorithm and PTM Limit Mach rules, initial PTM safety requirements and safety assessment documents, a detailed description of the design, development, and initial evaluations of the proposed flight crew HMI, an overview of the methodology and results of PTM pilot training

  20. Trajectories of metabolic syndrome development in young adults.

    Directory of Open Access Journals (Sweden)

    Vivian T W Poon

    Full Text Available Metabolic syndrome (MetS is a constellation of metabolic aberrations that collectively increase the risk for cardiovascular disease and type 2 diabetes. Greater understanding of MetS developments may provide insight into targeted prevention strategies for individuals at greatest risk. The purpose of this study was to i identify distinct patterns of longitudinal MetS development and; ii develop a character profile that differentiates groups by level of MetS risk.Data from the Coronary Artery Risk Development in Young Adults (CARDIA study (n = 3 804; 18-30 y was obtained by limited access application from the National Heart, Lung, and Blood Institute and used for this analysis. MetS, as defined by the Harmonized criteria, was assessed over a 20 year follow-up period. Group-level trajectory analysis identified 4 distinct groups with varying rates of component development [No (23.8% of sample; Low (33.5%; Moderate (35.3%; and High MetS (7.4%]. After adjusting for covariates, individuals in the At-Risk groups (Low, Moderate and High MetS were more likely to be of black ethnicity (1.37, 1.14-1.66, have a family history of cardiovascular disease (1.61, 1.31-1.97 and history of dieting (1.69, 1.20-2.39 when compared to the No Risk trajectory group (No MetS. Conversely, increasing baseline education (0.76, 0.65-0.89 and aerobic fitness (0.55, 0.47-0.64 was inversely associated with At-Risk group membership.Results suggest distinct profiles of MetS development that can be identified by baseline risk factors. Further research is necessary to understand the clinical implication of intermediate MetS development groups with respect to overall cardiometabolic risk.

  1. Trajectory of the Arctic as an integrated system.

    Science.gov (United States)

    Hinzman, Larry D; Deal, Clara J; McGuire, A David; Mernild, Sebastian H; Polyakov, Igor V; Walsh, John E

    2013-12-01

    Although much remains to be learned about the Arctic and its component processes, many of the most urgent scientific, engineering, and social questions can only be approached through a broader system perspective. Here, we address interactions between components of the Arctic system and assess feedbacks and the extent to which feedbacks (1) are now underway in the Arctic and (2) will shape the future trajectory of the Arctic system. We examine interdependent connections among atmospheric processes, oceanic processes, sea-ice dynamics, marine and terrestrial ecosystems, land surface stocks of carbon and water, glaciers and ice caps, and the Greenland ice sheet. Our emphasis on the interactions between components, both historical and anticipated, is targeted on the feedbacks, pathways, and processes that link these different components of the Arctic system. We present evidence that the physical components of the Arctic climate system are currently in extreme states, and that there is no indication that the system will deviate from this anomalous trajectory in the foreseeable future. The feedback for which the evidence of ongoing changes is most compelling is the surface albedo-temperature feedback, which is amplifying temperature changes over land (primarily in spring) and ocean (primarily in autumn-winter). Other feedbacks likely to emerge are those in which key processes include surface fluxes of trace gases, changes in the distribution of vegetation, changes in surface soil moisture, changes in atmospheric water vapor arising from higher temperatures and greater areas of open ocean, impacts of Arctic freshwater fluxes on the meridional overturning circulation of the ocean, and changes in Arctic clouds resulting from changes in water vapor content.

  2. Trajectories of the healthy ageing phenotype among middle-aged and older Britons, 2004-2013.

    Science.gov (United States)

    Tampubolon, Gindo

    2016-06-01

    Since the ageing population demands a response to ensure older people remain healthy and active, we studied the dynamics of a recently proposed healthy ageing phenotype. We drew the phenotype's trajectories and tested whether their levels and rates of change are influenced by health behaviours, comorbidities and socioeconomic positions earlier in the life course. The English Longitudinal Ageing Study, a prospective, nationally representative sample of people aged ≥50 years, measured a set of eight biomarkers which make up the outcome of the healthy ageing phenotype three times over nearly a decade (N2004=5009, N2008=5301, N2013=4455). A cluster of health behaviours, comorbidities and socioeconomic positions were also measured repeatedly. We assessed the phenotype's distribution non-parametrically, then fitted linear mixed models to phenotypic change and further examined time interactions with gender and socioeconomic position. We ran additional analyses to test robustness. Women had a wider distribution of the healthy ageing phenotype than men had. The phenotype declined annually by -0.242 (95% confidence interval [CI]: -0.352, -0.131). However, there was considerable heterogeneity in the levels and rates of phenotypic change. Women started at higher levels, then declined more steeply by -0.293 (CI: -0.403, -0.183) annually, leading to crossover in the trajectories. Smoking and physical activity assessed on the Allied Dunbar scale were strongly associated with the trajectories. Though marked by secular decline, the trajectories of the healthy ageing phenotype showed distinct socioeconomic gradients. The trajectories were also susceptible to variations in health behaviours, strengthening the case for serial interventions to attain healthy and active ageing. Copyright © 2016 The Author. Published by Elsevier Ireland Ltd.. All rights reserved.

  3. 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.

  4. Developmental Trajectories of Peer-Reported Aggressive Behavior: The Role of Friendship Understanding, Friendship Quality, and Friends’ Aggressive Behavior

    Science.gov (United States)

    Malti, Tina; McDonald, Kristina; Rubin, Kenneth H.; Rose-Krasnor, Linda; Booth-LaForce, Cathryn

    2015-01-01

    Objective To investigate developmental trajectories in peer-reported aggressive behavior across the transition from elementary-to-middle school, and whether aggressive behavior trajectories were associated with friendship quality, friends’ aggressive behavior, and the ways in which children think about their friendships. Method Participants included a community sample of 230 5th grade children who were assessed when they made a transition from elementary-to-middle school (6th grade). Peer nominations were used to assess the target child’s and friend’s aggressive behavior. Self- and friend reports were used to measure friendship quality; friendship understanding was assessed via a structured interview. Results General Growth Mixture Modeling (GGMM) revealed three distinct trajectories of peer-reported aggressive behavior across the school transition: low-stable, decreasing, and increasing. Adolescents’ understanding of friendship formation differentiated the decreasing from the low-stable aggressive behavior trajectories, and the understanding of friendship trust differentiated the increasing from the low-stable aggressive and decreasing aggressive behavior trajectories. Conclusions The findings indicated that a sophisticated understanding of friendship may serve as a protective factor for initially aggressive adolescents as they transition into middle school. Promoting a deepened understanding of friendship relations and their role in one’s own and others’ well-being may serve as an important prevention and intervention strategy to reduce aggressive behavior. PMID:26688775

  5. Developmental Trajectories of Peer-Reported Aggressive Behavior: The Role of Friendship Understanding, Friendship Quality, and Friends' Aggressive Behavior.

    Science.gov (United States)

    Malti, Tina; McDonald, Kristina; Rubin, Kenneth H; Rose-Krasnor, Linda; Booth-LaForce, Cathryn

    2015-10-01

    To investigate developmental trajectories in peer-reported aggressive behavior across the transition from elementary-to-middle school, and whether aggressive behavior trajectories were associated with friendship quality, friends' aggressive behavior, and the ways in which children think about their friendships. Participants included a community sample of 230 5 th grade children who were assessed when they made a transition from elementary-to-middle school (6 th grade). Peer nominations were used to assess the target child's and friend's aggressive behavior. Self- and friend reports were used to measure friendship quality; friendship understanding was assessed via a structured interview. General Growth Mixture Modeling (GGMM) revealed three distinct trajectories of peer-reported aggressive behavior across the school transition: low-stable, decreasing, and increasing. Adolescents' understanding of friendship formation differentiated the decreasing from the low-stable aggressive behavior trajectories, and the understanding of friendship trust differentiated the increasing from the low-stable aggressive and decreasing aggressive behavior trajectories. The findings indicated that a sophisticated understanding of friendship may serve as a protective factor for initially aggressive adolescents as they transition into middle school. Promoting a deepened understanding of friendship relations and their role in one's own and others' well-being may serve as an important prevention and intervention strategy to reduce aggressive behavior.

  6. Soft pomeron and lower-trajectory intercepts

    International Nuclear Information System (INIS)

    Cudell, J.R.; Kang, K.

    1999-01-01

    We present a preliminary report on the determination of the intercepts and couplings of the soft pomeron and of the p/ω and f/a trajectories from the largest data set available for all total cross sections and real parts of the hadronic amplitudes. Factorization is reasonably satisfied by the pomeron couplings, which allows us to make predictions on γγ and γp total cross sections. In addition we show that these data cannot discriminate between fits based on a simple Regge pomeron-pole and on an asymptotic log 2 s-type behaviour, implying that the effect of unitarization is negligible. Also we examine the range of validity in energy of the fit, and the bounds that these data lace on the odderon and on the hard pomeron. (author)

  7. 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.

  8. 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.

  9. Bell trajectories for revealing quantum control mechanisms

    International Nuclear Information System (INIS)

    Dennis, Eric; Rabitz, Herschel

    2003-01-01

    The dynamics induced while controlling quantum systems by optimally shaped laser pulses have often been difficult to understand in detail. A method is presented for quantifying the importance of specific sequences of quantum transitions involved in the control process. The method is based on a ''beable'' formulation of quantum mechanics due to John Bell that rigorously maps the quantum evolution onto an ensemble of stochastic trajectories over a classical state space. Detailed mechanism identification is illustrated with a model seven-level system. A general procedure is presented to extract mechanism information directly from closed-loop control experiments. Application to simulated experimental data for the model system proves robust with up to 25% noise

  10. Classical trajectory in non-relativistic scattering

    International Nuclear Information System (INIS)

    Williams, A.C.

    1978-01-01

    With the statistical interpretation of quantum mechanics as a guide, the classical trajectory is incorporated into quantum scattering theory. The Feynman path integral formalism is used as a starting point, and classical transformation theory is applied to the phase of the wave function so derived. This approach is then used to derive an expression for the scattering amplitude for potential scattering. It is found that the amplitude can be expressed in an impact parameter representation similar to the Glauber formalism. Connections are then made to the Glauber approximation and to semiclassical approximations derived from the Feynman path integral formalism. In extending this analysis to projectile-nucleus scattering, an approximation scheme is given with the first term being the same as in Glauber's multiple scattering theory. Higher-order approximations, thus, are found to give corrections to the fixed scatterer form of the impulse approximation inherent in the Glauber theory

  11. The role of locus of control and coping style in predicting longitudinal PTSD-trajectories after combat exposure

    DEFF Research Database (Denmark)

    Karstoft, K. I.; Armour, C.; Elklit, A.

    2015-01-01

    Israeli soldiers with or without combat stress reaction (CSR) from the Lebanon war were assessed 1, 2, and 20 years after the war. Combat exposure, LOC, and coping style were then investigated as covariates of the trajectories of resilience, recovery, delayed onset, and chronicity. Symptomatic...... trajectories in the CSR and the non-CSR group were significantly associated to varying degrees with perceived life threat during combat (ORs: 1.76-2.53), internal LOC (0.77-0.87), emotional coping style (0.28-0.34), and low use of problem-focused coping (2.12-3.11). In conclusion, assessment of LOC and coping...

  12. Camera Trajectory fromWide Baseline Images

    Science.gov (United States)

    Havlena, M.; Torii, A.; Pajdla, T.

    2008-09-01

    Camera trajectory estimation, which is closely related to the structure from motion computation, is one of the fundamental tasks in computer vision. Reliable camera trajectory estimation plays an important role in 3D reconstruction, self localization, and object recognition. There are essential issues for a reliable camera trajectory estimation, for instance, choice of the camera and its geometric projection model, camera calibration, image feature detection and description, and robust 3D structure computation. Most of approaches rely on classical perspective cameras because of the simplicity of their projection models and ease of their calibration. However, classical perspective cameras offer only a limited field of view, and thus occlusions and sharp camera turns may cause that consecutive frames look completely different when the baseline becomes longer. This makes the image feature matching very difficult (or impossible) and the camera trajectory estimation fails under such conditions. These problems can be avoided if omnidirectional cameras, e.g. a fish-eye lens convertor, are used. The hardware which we are using in practice is a combination of Nikon FC-E9 mounted via a mechanical adaptor onto a Kyocera Finecam M410R digital camera. Nikon FC-E9 is a megapixel omnidirectional addon convertor with 180° view angle which provides images of photographic quality. Kyocera Finecam M410R delivers 2272×1704 images at 3 frames per second. The resulting combination yields a circular view of diameter 1600 pixels in the image. Since consecutive frames of the omnidirectional camera often share a common region in 3D space, the image feature matching is often feasible. On the other hand, the calibration of these cameras is non-trivial and is crucial for the accuracy of the resulting 3D reconstruction. We calibrate omnidirectional cameras off-line using the state-of-the-art technique and Mičušík's two-parameter model, that links the radius of the image point r to the

  13. Optimal carbon emissions trajectories when damages depend on the rate or level of global warming

    International Nuclear Information System (INIS)

    Peck, S.C.; Teisberg, T.J.

    1994-01-01

    The authors extend earlier work with the Carbon Emissions Trajectory Assessment model (CETA) to consider a number of issues relating to the nature of optimal carbon emissions trajectories. They first explore model results when warming costs are associated with the rate of temperature rise, rather than with its level, as in earlier work. It is found that optimal trajectories are more strongly affected by the degree of non-linearity in the warming cost function than by whether the cost function is driven by the warming level or the warming rate. The authors briefly explore the implications of simple uncertainty and risk aversion for optimal emissions trajectories to be somewhat lower, but that the effect is not noticeable in the near term and not dramatic in the long term; the long term effect on the shadow price of carbon is more marked, however. Finally, they experiment with scaling up the warming cost functions until optimal policies are approximately the same as a policy of stabilising emissions at the 1990 level. Based on the results of this experiment, it is concluded that damages would have to be very high to justify anything like a stabilization policy; and even in this case, a policy allowing intertemporal variation in emissions would be better. 18 refs., 15 figs

  14. Maximum likelihood-based analysis of photon arrival trajectories in single-molecule FRET

    Energy Technology Data Exchange (ETDEWEB)

    Waligorska, Marta [Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland); Molski, Andrzej, E-mail: amolski@amu.edu.pl [Adam Mickiewicz University, Faculty of Chemistry, Grunwaldzka 6, 60-780 Poznan (Poland)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer We study model selection and parameter recovery from single-molecule FRET experiments. Black-Right-Pointing-Pointer We examine the maximum likelihood-based analysis of two-color photon trajectories. Black-Right-Pointing-Pointer The number of observed photons determines the performance of the method. Black-Right-Pointing-Pointer For long trajectories, one can extract mean dwell times that are comparable to inter-photon times. -- Abstract: When two fluorophores (donor and acceptor) are attached to an immobilized biomolecule, anti-correlated fluctuations of the donor and acceptor fluorescence caused by Foerster resonance energy transfer (FRET) report on the conformational kinetics of the molecule. Here we assess the maximum likelihood-based analysis of donor and acceptor photon arrival trajectories as a method for extracting the conformational kinetics. Using computer generated data we quantify the accuracy and precision of parameter estimates and the efficiency of the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in selecting the true kinetic model. We find that the number of observed photons is the key parameter determining parameter estimation and model selection. For long trajectories, one can extract mean dwell times that are comparable to inter-photon times.

  15. 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.

  16. Rapid Preliminary Design of Interplanetary Trajectories Using the Evolutionary Mission Trajectory Generator

    Science.gov (United States)

    Englander, Jacob

    2016-01-01

    Preliminary design of interplanetary missions is a highly complex process. The mission designer must choose discrete parameters such as the number of flybys, the bodies at which those flybys are performed, and in some cases the final destination. In addition, a time-history of control variables must be chosen that defines the trajectory. There are often many thousands, if not millions, of possible trajectories to be evaluated. This can be a very expensive process in terms of the number of human analyst hours required. An automated approach is therefore very desirable. This work presents such an approach by posing the mission design problem as a hybrid optimal control problem. The method is demonstrated on notional high-thrust chemical and low-thrust electric propulsion missions. In the low-thrust case, the hybrid optimal control problem is augmented to include systems design optimization.

  17. Long-term trajectories of posttraumatic stress disorder in veterans

    DEFF Research Database (Denmark)

    Karstoft, Karen-Inge; Armour, Cherie; Elklit, Ask

    2013-01-01

    OBJECTIVE: To (1) identify long-term trajectories of combat-induced posttraumatic stress disorder (PTSD) symptoms over a 20-year period from 1983 to 2002 in veterans with and without combat stress reaction (CSR) and (2) identify social predictors of these trajectories. METHOD: A latent growth...

  18. Model-based segmentation and classification of trajectories (Extended abstract)

    NARCIS (Netherlands)

    Alewijnse, S.P.A.; Buchin, K.; Buchin, M.; Sijben, S.; Westenberg, M.A.

    2014-01-01

    We present efficient algorithms for segmenting and classifying a trajectory based on a parameterized movement model like the Brownian bridge movement model. Segmentation is the problem of subdividing a trajectory into parts such that each art is homogeneous in its movement characteristics. We

  19. BALCO 6/7-DoF trajectory model

    NARCIS (Netherlands)

    Wey, P.; Corriveau, D.; Saitz, T.A.; Ruijter, W. de; Strömbäck, P.

    2016-01-01

    BALCO is a six- and seven-degree-of-freedom trajectory simulation program based on the mathematical model defined by the NATO Standardization Recommendation 4618. The primary goal of BALCO is to compute high-fidelity trajectories for both conventional and precision-guided projectiles. The 6-DoF

  20. 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.

  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. Initial Concept of Operations for Full Management by Trajectory

    Science.gov (United States)

    Fernandes, Alicia D.; Atkins, Steve; Leiden, Ken; Kaler, Curt; Evans, Mark; Bell, Alan; Kilbourne, Todd; Jackson, Michael

    2017-01-01

    This document describes Management by Trajectory (MBT), a concept for future air traffic management (ATM) in which flights are assigned four-dimensional trajectories (4DTs) through a negotiation process between the Federal Aviation Administration (FAA) and flight operators that respects the flight operator's goals while complying with National Airspace System (NAS) constraints.

  3. 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.

  4. Underwater navigation using diffusion-based trajectory observers

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Opderbecke, Jan

    2007-01-01

    This paper addresses the issue of estimating underwater vehicle trajectories using gyro-Doppler (body-fixed velocities) and acoustic positioning signals (earth-fixed positions). The approach consists of diffusion-based observers processing a whole trajectory segment at a time, allowing the consid...

  5. Optimal Hankel Norm Model Reduction by Truncation of Trajectories

    NARCIS (Netherlands)

    Roorda, B.; Weiland, S.

    2000-01-01

    We show how optimal Hankel-norm approximations of dynamical systems allow for a straightforward interpretation in terms of system trajectories. It is shown that for discrete time single-input systems optimal reductions are obtained by cutting 'balanced trajectories', i.e., by disconnecting the past

  6. 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…

  7. 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])…

  8. Energy-efficient Trajectory Tracking for Mobile Devices

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Bhattacharya, Sourav; Blunck, Henrik

    2011-01-01

    Emergent location-aware applications often require tracking trajectories of mobile devices over a long period of time. To be useful, the tracking has to be energy-efficient to avoid having a major impact on the battery life of the mobile de vice. Furthermore, when trajectory information needs to ...

  9. Integrated trajectory control and collision avoidance for automated driving

    NARCIS (Netherlands)

    Verhaegh, J.; Ploeg, J.; Nunen, E. van; Teerhuis, A.

    2017-01-01

    This paper presents a method for trajectory control, based on feedback linearization to guide an Automatic Guided Vehicle (AGV). The novelty of this work, is the adaptation of a reference trajectory with respect to a desired velocity in real-time to avoid collisions using a time-scaling mechanism.

  10. Trajectory Shape Analysis and Anomaly Detection Utilizing Information Theory Tools

    Directory of Open Access Journals (Sweden)

    Yuejun Guo

    2017-06-01

    Full Text Available In this paper, we propose to improve trajectory shape analysis by explicitly considering the speed attribute of trajectory data, and to successfully achieve anomaly detection. The shape of object motion trajectory is modeled using Kernel Density Estimation (KDE, making use of both the angle attribute of the trajectory and the speed of the moving object. An unsupervised clustering algorithm, based on the Information Bottleneck (IB method, is employed for trajectory learning to obtain an adaptive number of trajectory clusters through maximizing the Mutual Information (MI between the clustering result and a feature set of the trajectory data. Furthermore, we propose to effectively enhance the performance of IB by taking into account the clustering quality in each iteration of the clustering procedure. The trajectories are determined as either abnormal (infrequently observed or normal by a measure based on Shannon entropy. Extensive tests on real-world and synthetic data show that the proposed technique behaves very well and outperforms the state-of-the-art methods.

  11. Complexity Science Applications to Dynamic Trajectory Management: Research Strategies

    Science.gov (United States)

    Sawhill, Bruce; Herriot, James; Holmes, Bruce J.; Alexandrov, Natalia

    2009-01-01

    The promise of the Next Generation Air Transportation System (NextGen) is strongly tied to the concept of trajectory-based operations in the national airspace system. Existing efforts to develop trajectory management concepts are largely focused on individual trajectories, optimized independently, then de-conflicted among each other, and individually re-optimized, as possible. The benefits in capacity, fuel, and time are valuable, though perhaps could be greater through alternative strategies. The concept of agent-based trajectories offers a strategy for automation of simultaneous multiple trajectory management. The anticipated result of the strategy would be dynamic management of multiple trajectories with interacting and interdependent outcomes that satisfy multiple, conflicting constraints. These constraints would include the business case for operators, the capacity case for the Air Navigation Service Provider (ANSP), and the environmental case for noise and emissions. The benefits in capacity, fuel, and time might be improved over those possible under individual trajectory management approaches. The proposed approach relies on computational agent-based modeling (ABM), combinatorial mathematics, as well as application of "traffic physics" concepts to the challenge, and modeling and simulation capabilities. The proposed strategy could support transforming air traffic control from managing individual aircraft behaviors to managing systemic behavior of air traffic in the NAS. A system built on the approach could provide the ability to know when regions of airspace approach being "full," that is, having non-viable local solution space for optimizing trajectories in advance.

  12. Aircraft path planning with the use of smooth trajectories

    Science.gov (United States)

    Belokon', S. A.; Zolotukhin, Yu. N.; Nesterov, A. A.

    2017-01-01

    A simplified method of plane trajectory calculation is proposed for solving the problem of planning a path defined by a sequence of waypoints. The trajectory consists of oriented segments of straight lines joined by clothoids (Cornu spirals). The efficiency of the method is validated by means of numerical simulations in the MATLAB/Simulink environment.

  13. 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…

  14. 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…

  15. 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…

  16. 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....

  17. Rare behavior of growth processes via umbrella sampling of trajectories

    Science.gov (United States)

    Klymko, Katherine; Geissler, Phillip L.; Garrahan, Juan P.; Whitelam, Stephen

    2018-03-01

    We compute probability distributions of trajectory observables for reversible and irreversible growth processes. These results reveal a correspondence between reversible and irreversible processes, at particular points in parameter space, in terms of their typical and atypical trajectories. Thus key features of growth processes can be insensitive to the precise form of the rate constants used to generate them, recalling the insensitivity to microscopic details of certain equilibrium behavior. We obtained these results using a sampling method, inspired by the "s -ensemble" large-deviation formalism, that amounts to umbrella sampling in trajectory space. The method is a simple variant of existing approaches, and applies to ensembles of trajectories controlled by the total number of events. It can be used to determine large-deviation rate functions for trajectory observables in or out of equilibrium.

  18. 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.

  19. Optimal heliocentric trajectories for solar sail with minimum area

    Science.gov (United States)

    Petukhov, Vyacheslav G.

    2018-05-01

    The fixed-time heliocentric trajectory optimization problem is considered for planar solar sail with minimum area. Necessary optimality conditions are derived, a numerical method for solving the problem is developed, and numerical examples of optimal trajectories to Mars, Venus and Mercury are presented. The dependences of the minimum area of the solar sail from the date of departure from the Earth, the time of flight and the departing hyperbolic excess of velocity are analyzed. In particular, for the rendezvous problem (approaching a target planet with zero relative velocity) with zero departing hyperbolic excess of velocity for a flight duration of 1200 days it was found that the minimum area-to-mass ratio should be about 12 m2/kg for trajectory to Venus, 23.5 m2/kg for the trajectory to Mercury and 25 m2/kg for trajectory to Mars.

  20. 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.

  1. Interpersonal Problems and Developmental Trajectories of Binge Eating Disorder

    Science.gov (United States)

    Blomquist, Kerstin K.; Ansell, Emily B.; White, Marney A.; Masheb, Robin M.; Grilo, Carlos M.

    2012-01-01

    Objective To explore associations between specific interpersonal constructs and the developmental progression of behaviors leading to binge eating disorder (BED). Method Eighty-four consecutively evaluated, treatment-seeking obese (BMI ≥ 30) men and women with BED were assessed with structured diagnostic and clinical interviews and completed a battery of established measures to assess the current and developmental eating- and weight-related variables as well as interpersonal functioning. Results Using the interpersonal circumplex structural summary method, amplitude, elevation, the affiliation dimension, and the quadratic coefficient for the dominance dimension were associated with eating and weight-related developmental variables. The amplitude coefficient and more extreme interpersonal problems on the dominance dimension (quadratic)—i.e., problems with being extremely high (domineering) or low in dominance (submissive)—were significantly associated with ayounger age at onset of binge eating, BED, and overweight as well as accounted for significant variance in age at binge eating, BED, and overweight onset. Greater interpersonal problems with having an overly affiliative interpersonal style were significantly associated with, and accounted for significant variance in, ayounger age at diet onset. Discussion Findings provide further support for the importance of interpersonal problems among adults with BED and converge with recent work highlighting the importance of specific types of interpersonal problems for understanding heterogeneity and different developmental trajectories of individuals with BED. PMID:22727087

  2. Developmental Trajectory of Motor Deficits in Preschool Children with ADHD.

    Science.gov (United States)

    Sweeney, Kristie L; Ryan, Matthew; Schneider, Heather; Ferenc, Lisa; Denckla, Martha Bridge; Mark Mahone, E

    2018-05-14

    Motor deficits persisting into childhood (>7 years) are associated with increased executive and cognitive dysfunction, likely due to parallel neural circuitry. This study assessed the longitudinal trajectory of motor deficits in preschool children with ADHD, compared to typically developing (TD) children, in order to identify individuals at risk for anomalous neurological development. Participants included 47 children (21 ADHD, 26 TD) ages 4-7 years who participated in three visits (V1, V2, V3), each one year apart (V1=48-71 months, V2=60-83 months, V3=72-95 months). Motor variables assessed included speed (finger tapping and sequencing), total overflow, and axial movements from the Revised Physical and Neurological Examination for Subtle Signs (PANESS). Effects for group, visit, and group-by-visit interaction were examined. There were significant effects for group (favoring TD) for finger tapping speed and total axial movements, visit (performance improving with age for all 4 variables), and a significant group-by-visit interaction for finger tapping speed. Motor speed (repetitive finger tapping) and quality of axial movements are sensitive markers of anomalous motor development associated with ADHD in children as young as 4 years. Conversely, motor overflow and finger sequencing speed may be less sensitive in preschool, due to ongoing wide variations in attainment of these milestones.

  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. Trajectories of quality of life, life satisfaction, and psychological adjustment after prostate cancer.

    Science.gov (United States)

    Chambers, Suzanne K; Ng, Shu Kay; Baade, Peter; Aitken, Joanne F; Hyde, Melissa K; Wittert, Gary; Frydenberg, Mark; Dunn, Jeff

    2017-10-01

    To describe trajectories of health-related quality of life (QoL), life satisfaction, and psychological adjustment for men with prostate cancer over the medium to long term and identify predictors of poorer outcomes using growth mixture models. One-thousand sixty-four (82.4% response) men diagnosed with prostate cancer were recruited close to diagnosis and assessed over a 72-month (6-year) period with self-report assessment of health-related QoL, life satisfaction, cancer-related distress, and prostate specific antigen anxiety. Urinary, bowel, and sexual function were also assessed using validated questionnaires. Poorer physical QOL was predicted by older age, lower education, lower income, comorbidities, and receiving hormone therapy. Lower life satisfaction was related to younger age, lower income, not being partnered, and comorbidities. Poorer psychological trajectories were predicted by younger age, lower income, comorbidities, and receiving radical prostatectomy or brachytherapy. Better urinary, bowel, and sexual function were related to better global outcomes over time. Anxiety about prostate specific antigen testing was rare. Distinct trajectories exist for medium- to long-term QoL, life satisfaction, and psychological adjustment after prostate cancer; with age and socioeconomic deprivation playing a differential role in men's survivorship profile and the impact of functional status on outcomes increasing over time. These results reinforce the need for an appraisal of men's life course in addition to treatment side effects when planning survivorship care after cancer. © 2016 The Authors. Psycho-Oncology Published by John Wiley & Sons Ltd.

  5. Validity of the Type D personality construct in Danish post-MI patients and healthy controls

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Denollet, Johan

    2004-01-01

    Type D personality has been associated with increased risk of depression, vital exhaustion, social alienation, a higher number of reinfarctions, and higher mortality rates in patients with established coronary artery disease (CAD) independent of traditional biomedical risk factors. The construct ...

  6. 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

  7. Cannabis use and psychotic-like experiences trajectories during early adolescence: the coevolution and potential mediators.

    Science.gov (United States)

    Bourque, Josiane; Afzali, Mohammad H; O'Leary-Barrett, Maeve; Conrod, Patricia

    2017-12-01

    The authors sought to model the different trajectories of psychotic-like experiences (PLE) during adolescence and to examine whether the longitudinal relationship between cannabis use and PLE is mediated by changes in cognitive development and/or change in anxiety or depression symptoms. A total of 2,566 youths were assessed every year for 4-years (from 13- to 16-years of age) on clinical, substance use and cognitive development outcomes. Latent class growth models identified three trajectories of PLE: low decreasing (83.9%), high decreasing (7.9%), and moderate increasing class (8.2%). We conducted logistic regressions to investigate whether baseline levels and growth in cannabis use were associated with PLE trajectory membership. Then, we examined the effects of potential mediators (growth in cognition and anxiety/depression) on the relationship between growth in cannabis use and PLE trajectory. A steeper growth in cannabis use from 13- to 16-years was associated with a higher likelihood of being assigned to the moderate increasing trajectory of PLE [odds ratio, 2.59; 95% confidence interval (CI), 1.11-6.03], when controlling for cumulative cigarette use. Growth in depression symptoms, not anxiety or change in cognitive functioning, mediated the relationship between growth in cannabis use and the PLE moderate increasing group (indirect effect: 0.07; 95% CI, 0.03-0.11). Depression symptoms partially mediated the longitudinal link between cannabis use and PLE in adolescents, suggesting that there may be a preventative effect to be gained from targeting depression symptoms, in addition to attempting to prevent cannabis use in youth presenting increasing psychotic experiences. © 2017 Association for Child and Adolescent Mental Health.

  8. Cigarette Smoking Trajectories From Sixth to Twelfth Grade: Associated Substance Use and High School Dropout.

    Science.gov (United States)

    Orpinas, Pamela; Lacy, Beth; Nahapetyan, Lusine; Dube, Shanta R; Song, Xiao

    2016-02-01

    The purpose of this longitudinal study was to identify distinct trajectories of cigarette smoking from sixth to twelfth grade and to characterize these trajectories by use of other drugs and high school dropout. The diverse sample for this analysis consisted of a cohort of 611 students from Northeast Georgia who participated in the Healthy Teens Longitudinal Study (2003-2009). Students completed seven yearly assessments from sixth through twelfth grade. We used semi-parametric, group-based modeling to identify groups of students whose smoking behavior followed a similar progression over time. Current smoking (past 30 day) increased from 6.9% among sixth graders to 28.8% among twelfth graders. Four developmental trajectories of cigarette smoking were identified: Abstainers/Sporadic Users (71.5% of the sample), Late Starters (11.3%), Experimenters (9.0%), and Continuous Users (8.2%). The Abstainer/Sporadic User trajectory was composed of two distinct groups: those who never reported any tobacco use (True Abstainers) and those who reported sporadic, low-level use (Sporadic Users). The True Abstainers reported significantly less use of alcohol and other drugs and lower dropout rates than students in all other trajectories, and Sporadic Users had worse outcomes than True Abstainers. Experimenters and Continuous Users reported the highest drug use. Over one-third of Late Starters (35.8%) and almost half of Continuous Users (44.4%) dropped out of high school. Cigarette smoking was associated with behavioral and academic problems. Results support early and continuous interventions to reduce use of tobacco and other drugs and prevent high school dropout. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. 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

  10. Disordered gambling: etiology, trajectory, and clinical considerations.

    Science.gov (United States)

    Shaffer, Howard J; Martin, Ryan

    2011-01-01

    Gambling-related research has advanced rapidly during the past 20 years. As a result of expanding interest in pathological gambling (PG), stakeholders (e.g., clinicians, regulators, and policy makers) have a better understanding of excessive gambling, including its etiology (e.g., neurobiological/neurogenetic, psychological, and sociological factors) and trajectory (e.g., initiation, course, and adaptation to gambling exposure). In this article, we examine these advances in PG-related research and then consider some of the clinical implications of these advances. We consider criteria changes for PG recently proposed by the DSM-V Impulse Control Work Group for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). We also review how clinicians can more accurately and efficiently diagnose clients seeking help for gambling-related problems by utilizing brief screens. Finally, we consider the importance of future research that can identify behavioral markers for PG. We suggest that identifying these markers will allow clinicians to make earlier diagnoses, recommend targeted treatments, and advance secondary prevention efforts. © 2011 by Annual Reviews. All rights reserved

  11. Assisted reproductive travel: UK patient trajectories.

    Science.gov (United States)

    Hudson, Nicky; Culley, Lorraine

    2011-11-01

    Media reporting of 'fertility tourism' tends to portray those who travel as a cohesive group, marked by their desperation and/or selfishness and propensity towards morally questionable behaviour. However, to date little has been known about the profile of those leaving the UK for treatment. This paper discusses the first UK-based study of patient assisted reproduction travel that was designed to explore individual travel trajectories. It is argued that existing ways of conceptualizing cross-border reproductive care as 'fertility or reproductive tourism' are in danger of essentializing what the data suggest are diverse, complex and often ambiguous motivations for reproductive travel. The concept of seriality is used to suggest that, whilst 'reproductive tourists' share some characteristics, they also differ in significant ways. This paper argues that, through an examination of the personal landscapes of fertility travel, the diverse processes involved in reproductive travel can be better understood and policymakers can be assisted to avoid what might be regarded as simplistic responses to cross-border reproductive care. Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  12. Synchronized Trajectories in a Climate "Supermodel"

    Science.gov (United States)

    Duane, Gregory; Schevenhoven, Francine; Selten, Frank

    2017-04-01

    Differences in climate projections among state-of-the-art models can be resolved by connecting the models in run-time, either through inter-model nudging or by directly combining the tendencies for corresponding variables. Since it is clearly established that averaging model outputs typically results in improvement as compared to any individual model output, averaged re-initializations at typical analysis time intervals also seems appropriate. The resulting "supermodel" is more like a single model than it is like an ensemble, because the constituent models tend to synchronize even with limited inter-model coupling. Thus one can examine the properties of specific trajectories, rather than averaging the statistical properties of the separate models. We apply this strategy to a study of the index cycle in a supermodel constructed from several imperfect copies of the SPEEDO model (a global primitive-equation atmosphere-ocean-land climate model). As with blocking frequency, typical weather statistics of interest like probabilities of heat waves or extreme precipitation events, are improved as compared to the standard multi-model ensemble approach. In contrast to the standard approach, the supermodel approach provides detailed descriptions of typical actual events.

  13. Primordial spectra from sudden turning trajectory

    Science.gov (United States)

    Noumi, Toshifumi; Yamaguchi, Masahide

    2013-12-01

    Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the potential, the following two effects are generically induced: deformation of the inflationary background spacetime and conversion interactions between adiabatic and isocurvature perturbations, both of which can affect the primordial density perturbations. In this paper, we calculate primordial spectra in inflationary models with sudden turning potentials taking into account both of the two effects appropriately. We find that there are some non-trivial correlations between the two effects in the power spectrum and, as a consequence, the primordial scalar power spectrum has a peak around the scale exiting the horizon at the turn. Though both effects can induce parametric resonance amplifications, they are shown to be canceled out for the case with the canonical kinetic terms. The peak feature and the scale dependence of bispectra are also discussed.

  14. Pairwise Trajectory Management (PTM): Concept Overview

    Science.gov (United States)

    Jones, Kenneth M.; Graff, Thomas J.; Chartrand, Ryan C.; Carreno, Victor; Kibler, Jennifer L.

    2017-01-01

    Pairwise Trajectory Management (PTM) is an Interval Management (IM) concept that utilizes airborne and ground-based capabilities to enable the implementation of airborne pairwise spacing capabilities in oceanic regions. The goal of PTM is to use airborne surveillance and tools to manage an "at or greater than" inter-aircraft spacing. Due to the precision of Automatic Dependent Surveillance-Broadcast (ADS-B) information and the use of airborne spacing guidance, the PTM minimum spacing distance will be less than distances a controller can support with current automation systems that support oceanic operations. Ground tools assist the controller in evaluating the traffic picture and determining appropriate PTM clearances to be issued. Avionics systems provide guidance information that allows the flight crew to conform to the PTM clearance issued by the controller. The combination of a reduced minimum distance and airborne spacing management will increase the capacity and efficiency of aircraft operations at a given altitude or volume of airspace. This paper provides an overview of the proposed application, description of a few key scenarios, high level discussion of expected air and ground equipment and procedure changes, overview of a potential flight crew human-machine interface that would support PTM operations and some initial PTM benefits results.

  15. Trajectories entropy in dynamical graphs with memory

    Directory of Open Access Journals (Sweden)

    Francesco eCaravelli

    2016-04-01

    Full Text Available In this paper we investigate the application of non-local graph entropy to evolving and dynamical graphs. The measure is based upon the notion of Markov diffusion on a graph, and relies on the entropy applied to trajectories originating at a specific node. In particular, we study the model of reinforcement-decay graph dynamics, which leads to scale free graphs. We find that the node entropy characterizes the structure of the network in the two parameter phase-space describing the dynamical evolution of the weighted graph. We then apply an adapted version of the entropy measure to purely memristive circuits. We provide evidence that meanwhile in the case of DC voltage the entropy based on the forward probability is enough to characterize the graph properties, in the case of AC voltage generators one needs to consider both forward and backward based transition probabilities. We provide also evidence that the entropy highlights the self-organizing properties of memristive circuits, which re-organizes itself to satisfy the symmetries of the underlying graph.

  16. Self Conservation Trajectory in Nursing Homes

    Directory of Open Access Journals (Sweden)

    Ângela Simões

    2017-04-01

    Full Text Available Objectives: This article intends to present some of the results obtained during the research on the Promotion and Preservation of Dignity in the context of care in nursing homes, carried out in the context of the PhD in Nursing of the University of Lisbon. Methodology: Within the interpretative paradigm, Grounded Theory (GT was adopted as methodology. Data were collected through participant observation and interviews at an Nursing Home (IPSS with about 350 residents distributed through three residential structures in the county of Castelo Branco for 21 months, with residents, nurses and direct acting helpers as participants. The constant comparative analysis of the data occurred simultaneously, using the software NVivo 10® and NVivo 11®. From the data analysis it was possible to construct a middle-range theory - Promotion and Preservation of Dignity in Nursing Homes: Self Conservation. Results: A complex, unforeseen phenomenon, exposed to variability and multiple, constructed, deconstructed and reconstructed in the daily rhythms, in a continuous, systematic and dynamic manner. It follows a two-dimensional route that was called the Self Conservation Trajectory. On the one hand a personal, individual, although accompanied and promoted. On the other hand a profoundly social path. Is the first dimension of this route that will be presented in this article.

  17. Trajectories of parenting behavior and maternal depression.

    Science.gov (United States)

    Azak, Schale; Raeder, Sabine

    2013-06-01

    This study investigated trajectories of maternal parenting behavior across the infants' first 18 months of life in relation to maternal depression. Furthermore, predictors of the quality of the mother-infant relationship at 18 months were examined. Participants consisted of three types of mother-infant dyads: mothers with comorbid depression and anxiety (n=19), mothers with depression (n=7) and nondepressed mothers (n=24). Maternal behaviors and the quality of relationship were rated on a global scale (NICHD) from video-taped mother-infant interactions. Maternal behaviors rated at six, 12 and 18 months were collapsed into a composite variable maternal style. The quality of the relationship captured as dyadic mutuality was rated at 18 months. Comorbid and depressed mothers showed lower quality in maternal style compared with the nondepressed mothers at six months. Over the follow-up the comorbid mothers were lower in maternal style compared to the nondepressed mothers, but the comorbid mothers increased significantly in maternal style despite elevated depression symptoms. Mean maternal style and infant cognitive skills predicted the quality in relationship at 18 months suggesting that the mother-toddler relationship depends on contributions from the mother and the child. Higher growth in maternal style despite of depression symptoms among comorbid mothers was interpreted against the background that the majority of the comorbid mother-infant dyads received several treatments. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Trajectories of Behavioural Disturbances Across Dementia Types.

    Science.gov (United States)

    Linds, Alexandra B; Kirstein, Alana B; Freedman, Morris; Verhoeff, Nicolaas P L G; Wolf, Uri; Chow, Tiffany W

    2015-11-01

    To replicate a previous finding that the trajectory of the Neuropsychiatric Inventory (NPI) shifts in the sixth year of behavioural variant frontotemporal dementia (bvFTD). We evaluated longitudinal tracking with both the Frontal Behavioural Inventory (FBI) and NPI, comparing bvFTD against other dementias. Chart reviews over two to five years for patients with bvFTD (n=30), primary progressive aphasia (PPA, n=13) and Alzheimer's disease (AD, n=118) at an urban Canadian tertiary clinic specializing in dementia. Linear regressions of the longitudinal data tested predictors of annualized rates of change (ROC) in NPI and FBI total and subscales for apathy and disinhibition among dementia groups. The mode of the overall sample for the most advanced duration of illness observed was 5 years, with the median at 7 years. We did not find a crescendo-decrescendo pattern in scores although, for bvFTD and AD, high initial scores correlated with ensuing downward ROCs on the NPI and FBI. Educational level showed an influence on disinhibition ROCs. The FBI was no more revealing than the NPI for apathy and disinhibition scores in these dementias. A cognitive reserve effect on behavioural disturbance was supported but it may take longer than our 4 years of observing the clinical sample to record inflection points in the behavioural and psychiatric symptoms seen in bvFTD. The current data only imply that both apathy and disinhibition will diminish over the course of dementia.

  19. Programs To Optimize Spacecraft And Aircraft Trajectories

    Science.gov (United States)

    Brauer, G. L.; Petersen, F. M.; Cornick, D.E.; Stevenson, R.; Olson, D. W.

    1994-01-01

    POST/6D POST is set of two computer programs providing ability to target and optimize trajectories of powered or unpowered spacecraft or aircraft operating at or near rotating planet. POST treats point-mass, three-degree-of-freedom case. 6D POST treats more-general rigid-body, six-degree-of-freedom (with point masses) case. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Applications include computation of performance or capability of vehicle in ascent, or orbit, and during entry into atmosphere, simulation and analysis of guidance and flight-control systems, dispersion-type analyses and analyses of loads, general-purpose six-degree-of-freedom simulation of controlled and uncontrolled vehicles, and validation of performance in six degrees of freedom. Written in FORTRAN 77 and C language. Two machine versions available: one for SUN-series computers running SunOS(TM) (LAR-14871) and one for Silicon Graphics IRIS computers running IRIX(TM) operating system (LAR-14869).

  20. The emergence of an electric mobility trajectory

    International Nuclear Information System (INIS)

    Dijk, Marc; Orsato, Renato J.; Kemp, René

    2013-01-01

    In this paper, we analyse the emergence of a trajectory of electric moblity. We describe developments in electric vehicles before and after 2005. The central thesis of the paper is that electric mobility has crossed a critical threshold and is benefitting from various developments whose influence can be expected to grow in importance: high oil prices, carbon constraints, and rise of organised car sharing and intermodality. We find that the development of vehicle engine technology depends on changes in (fueling) infrastructure, changes in mobility, changes in the global car market, evolution of energy prices, climate policy, and changes in the electricity sector. Special attention is given to interaction of technological alternatives: how these work out for the future of battery electric vehicles, hybrid electric vehicles and hydrogen fuel cell vehicles. - Highlights: ► A socio-technical analysis of the recent history of electric vehicles. ► An exploration of the future of electric vehicles. ► We highlight the interaction of vehicle technology and mobility patterns.

  1. Trajectory Control of Rendezvous with Maneuver Target Spacecraft

    Science.gov (United States)

    Zhou, Zhinqiang

    2012-01-01

    In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

  2. VISUAL UAV TRAJECTORY PLAN SYSTEM BASED ON NETWORK MAP

    Directory of Open Access Journals (Sweden)

    X. L. Li

    2012-07-01

    Full Text Available The base map of the current software UP-30 using in trajectory plan for Unmanned Aircraft Vehicle is vector diagram. UP-30 draws navigation points manually. But in the field of operation process, the efficiency and the quality of work is influenced because of insufficient information, screen reflection, calculate inconveniently and other factors. If we do this work in indoor, the effect of external factors on the results would be eliminated, the network earth users can browse the free world high definition satellite images through downloading a client software, and can export the high resolution image by standard file format. This brings unprecedented convenient of trajectory plan. But the images must be disposed by coordinate transformation, geometric correction. In addition, according to the requirement of mapping scale ,camera parameters and overlap degree we can calculate exposure hole interval and trajectory distance between the adjacent trajectory automatically . This will improve the degree of automation of data collection. Software will judge the position of next point according to the intersection of the trajectory and the survey area and ensure the position of point according to trajectory distance. We can undertake the points artificially. So the trajectory plan is automatic and flexible. Considering safety, the date can be used in flying after simulating flight. Finally we can export all of the date using a key

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Visual Uav Trajectory Plan System Based on Network Map

    Science.gov (United States)

    Li, X. L.; Lin, Z. J.; Su, G. Z.; Wu, B. Y.

    2012-07-01

    The base map of the current software UP-30 using in trajectory plan for Unmanned Aircraft Vehicle is vector diagram. UP-30 draws navigation points manually. But in the field of operation process, the efficiency and the quality of work is influenced because of insufficient information, screen reflection, calculate inconveniently and other factors. If we do this work in indoor, the effect of external factors on the results would be eliminated, the network earth users can browse the free world high definition satellite images through downloading a client software, and can export the high resolution image by standard file format. This brings unprecedented convenient of trajectory plan. But the images must be disposed by coordinate transformation, geometric correction. In addition, according to the requirement of mapping scale ,camera parameters and overlap degree we can calculate exposure hole interval and trajectory distance between the adjacent trajectory automatically . This will improve the degree of automation of data collection. Software will judge the position of next point according to the intersection of the trajectory and the survey area and ensure the position of point according to trajectory distance. We can undertake the points artificially. So the trajectory plan is automatic and flexible. Considering safety, the date can be used in flying after simulating flight. Finally we can export all of the date using a key

  9. 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.

  10. 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.

  11. Adaptive density trajectory cluster based on time and space distance

    Science.gov (United States)

    Liu, Fagui; Zhang, Zhijie

    2017-10-01

    There are some hotspot problems remaining in trajectory cluster for discovering mobile behavior regularity, such as the computation of distance between sub trajectories, the setting of parameter values in cluster algorithm and the uncertainty/boundary problem of data set. As a result, based on the time and space, this paper tries to define the calculation method of distance between sub trajectories. The significance of distance calculation for sub trajectories is to clearly reveal the differences in moving trajectories and to promote the accuracy of cluster algorithm. Besides, a novel adaptive density trajectory cluster algorithm is proposed, in which cluster radius is computed through using the density of data distribution. In addition, cluster centers and number are selected by a certain strategy automatically, and uncertainty/boundary problem of data set is solved by designed weighted rough c-means. Experimental results demonstrate that the proposed algorithm can perform the fuzzy trajectory cluster effectively on the basis of the time and space distance, and obtain the optimal cluster centers and rich cluster results information adaptably for excavating the features of mobile behavior in mobile and sociology network.

  12. Quantum trajectories for time-dependent adiabatic master equations

    Science.gov (United States)

    Yip, Ka Wa; Albash, Tameem; Lidar, Daniel A.

    2018-02-01

    We describe a quantum trajectories technique for the unraveling of the quantum adiabatic master equation in Lindblad form. By evolving a complex state vector of dimension N instead of a complex density matrix of dimension N2, simulations of larger system sizes become feasible. The cost of running many trajectories, which is required to recover the master equation evolution, can be minimized by running the trajectories in parallel, making this method suitable for high performance computing clusters. In general, the trajectories method can provide up to a factor N advantage over directly solving the master equation. In special cases where only the expectation values of certain observables are desired, an advantage of up to a factor N2 is possible. We test the method by demonstrating agreement with direct solution of the quantum adiabatic master equation for 8-qubit quantum annealing examples. We also apply the quantum trajectories method to a 16-qubit example originally introduced to demonstrate the role of tunneling in quantum annealing, which is significantly more time consuming to solve directly using the master equation. The quantum trajectories method provides insight into individual quantum jump trajectories and their statistics, thus shedding light on open system quantum adiabatic evolution beyond the master equation.

  13. 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

  14. Drug use trajectory patterns among older drug users

    Directory of Open Access Journals (Sweden)

    Tyndall B

    2011-05-01

    Full Text Available Miriam Boeri, Thor Whalen, Benjamin Tyndall, Ellen BallardKennesaw State University, Department of Sociology and Criminal Justice, Kennesaw GA, USAAbstract: To better understand patterns of drug use trajectories over time, it is essential to have standard measures of change. Our goal here is to introduce measures we developed to quantify change in drug use behaviors. A secondary goal is to provide effective visualizations of these trajectories for applied use. We analyzed data from a sample of 92 older drug users (ages 45 to 65 to identify transition patterns in drug use trajectories across the life course. Data were collected for every year since birth using a mixed methods design. The community-drawn sample of active and former users were 40% female, 50% African American, and 60% reporting some college or greater. Their life histories provided retrospective longitudinal data on the diversity of paths taken throughout the life course and changes in drug use patterns that occurred over time. Bayesian analysis was used to model drug trajectories displayed by innovative computer graphics. The mathematical techniques and visualizations presented here provide the foundation for future models using Bayesian analysis. In this paper we introduce the concepts of transition counts, transition rates and relapse/remission rates, and we describe how these measures can help us better understand drug use trajectories. Depicted through these visual tools, measurements of discontinuous patterns provide a succinct view of individual drug use trajectories. The measures we use on drug use data will be further developed to incorporate contextual influences on the drug trajectory and build predictive models that inform rehabilitation efforts for drug users. Although the measures developed here were conceived to better examine drug use trajectories, the applications of these measures can be used with other longitudinal datasets.Keywords: drug use, trajectory patterns

  15. 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.

  16. Irritability Trajectories, Cortical Thickness, and Clinical Outcomes in a Sample Enriched for Preschool Depression.

    Science.gov (United States)

    Pagliaccio, David; Pine, Daniel S; Barch, Deanna M; Luby, Joan L; Leibenluft, Ellen

    2018-05-01

    Cross-sectional, longitudinal, and genetic associations exist between irritability and depression. Prior studies have examined developmental trajectories of irritability, clinical outcomes, and associations with child and familial depression. However, studies have not integrated neurobiological measures. The present study examined developmental trajectories of irritability, clinical outcomes, and cortical structure among preschoolers oversampled for depressive symptoms. Beginning at 3 to 5 years old, a sample of 271 children enriched for early depressive symptoms were assessed longitudinally by clinical interview. Latent class mixture models identified trajectories of irritability severity. Risk factors, clinical outcomes, and cortical thickness were compared across trajectory classes. Cortical thickness measures were extracted from 3 waves of magnetic resonance imaging at 7 to 12 years of age. Three trajectory classes were identified among these youth: 53.50% of children exhibited elevated irritability during preschool that decreased longitudinally, 30.26% exhibited consistently low irritability, and 16.24% exhibited consistently elevated irritability. Compared with other classes, the elevated irritability class exhibited higher rates of maternal depression, early life adversity, later psychiatric diagnoses, and functional impairment. Further, elevated baseline irritability predicted later depression beyond adversity and personal and maternal depression history. The elevated irritability class exhibited a thicker cortex in the left superior frontal and temporal gyri and the right inferior parietal lobule. Irritability manifested with specific developmental trajectories in this sample enriched for early depression. Persistently elevated irritability predicted poor psychiatric outcomes, higher risk for later depression, and decreased overall function later in development. Greater frontal, temporal, and parietal cortical thickness also was found, providing neural

  17. 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

  18. Anatomical variability in the trajectory of the inside-out transobturator vaginal tape technique (TVT-O)

    NARCIS (Netherlands)

    Hinoul, Piet; Vanormelingen, Linda; Roovers, Jan-Paul; de Jonge, Eric; Smajda, Stéfan

    2007-01-01

    An experimental surgical study on human cadavers was undertaken to assess variability in the trajectory followed by the needle during application of the inside-out transobturator tape suspension (TVT-O) technique. The TVT-O surgical procedures were performed on six fresh female cadavers according to

  19. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    Science.gov (United States)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  20. PARALLEL SPATIOTEMPORAL SPECTRAL CLUSTERING WITH MASSIVE TRAJECTORY DATA

    Directory of Open Access Journals (Sweden)

    Y. Z. Gu

    2017-09-01

    Full Text Available Massive trajectory data contains wealth useful information and knowledge. Spectral clustering, which has been shown to be effective in finding clusters, becomes an important clustering approaches in the trajectory data mining. However, the traditional spectral clustering lacks the temporal expansion on the algorithm and limited in its applicability to large-scale problems due to its high computational complexity. This paper presents a parallel spatiotemporal spectral clustering based on multiple acceleration solutions to make the algorithm more effective and efficient, the performance is proved due to the experiment carried out on the massive taxi trajectory dataset in Wuhan city, China.

  1. 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.

  2. ANALYTiC: An Active Learning System for Trajectory Classification.

    Science.gov (United States)

    Soares Junior, Amilcar; Renso, Chiara; Matwin, Stan

    2017-01-01

    The increasing availability and use of positioning devices has resulted in large volumes of trajectory data. However, semantic annotations for such data are typically added by domain experts, which is a time-consuming task. Machine-learning algorithms can help infer semantic annotations from trajectory data by learning from sets of labeled data. Specifically, active learning approaches can minimize the set of trajectories to be annotated while preserving good performance measures. The ANALYTiC web-based interactive tool visually guides users through this annotation process.

  3. Efficient One-click Browsing of Large Trajectory Sets

    DEFF Research Database (Denmark)

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

    2014-01-01

    presents a novel query type called sheaf, where users can browse trajectory data sets using a single mouse click. Sheaves are very versatile and can be used for location-based advertising, travel-time analysis, intersection analysis, and reachability analysis (isochrones). A novel in-memory trajectory...... index compresses the data by a factor of 12.4 and enables execution of sheaf queries in 40 ms. This is up to 2 orders of magnitude faster than existing work. We demonstrate the simplicity, versatility, and efficiency of sheaf queries using a real-world trajectory set consisting of 2.7 million...

  4. Fractional dynamics using an ensemble of classical trajectories

    Science.gov (United States)

    Sun, Zhaopeng; Dong, Hao; Zheng, Yujun

    2018-01-01

    A trajectory-based formulation for fractional dynamics is presented and the trajectories are generated deterministically. In this theoretical framework, we derive a new class of estimators in terms of confluent hypergeometric function (F11) to represent the Riesz fractional derivative. Using this method, the simulation of free and confined Lévy flight are in excellent agreement with the exact numerical and analytical results. In addition, the barrier crossing in a bistable potential driven by Lévy noise of index α is investigated. In phase space, the behavior of trajectories reveal the feature of Lévy flight in a better perspective.

  5. Diverging volumetric trajectories following pediatric traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Emily L. Dennis

    2017-01-01

    Full Text Available Traumatic brain injury (TBI is a significant public health concern, and can be especially disruptive in children, derailing on-going neuronal maturation in periods critical for cognitive development. There is considerable heterogeneity in post-injury outcomes, only partially explained by injury severity. Understanding the time course of recovery, and what factors may delay or promote recovery, will aid clinicians in decision-making and provide avenues for future mechanism-based therapeutics. We examined regional changes in brain volume in a pediatric/adolescent moderate-severe TBI (msTBI cohort, assessed at two time points. Children were first assessed 2–5 months post-injury, and again 12 months later. We used tensor-based morphometry (TBM to localize longitudinal volume expansion and reduction. We studied 21 msTBI patients (5 F, 8–18 years old and 26 well-matched healthy control children, also assessed twice over the same interval. In a prior paper, we identified a subgroup of msTBI patients, based on interhemispheric transfer time (IHTT, with significant structural disruption of the white matter (WM at 2–5 months post injury. We investigated how this subgroup (TBI-slow, N = 11 differed in longitudinal regional volume changes from msTBI patients (TBI-normal, N = 10 with normal WM structure and function. The TBI-slow group had longitudinal decreases in brain volume in several WM clusters, including the corpus callosum and hypothalamus, while the TBI-normal group showed increased volume in WM areas. Our results show prolonged atrophy of the WM over the first 18 months post-injury in the TBI-slow group. The TBI-normal group shows a different pattern that could indicate a return to a healthy trajectory.

  6. Reliability-based trajectory optimization using nonintrusive polynomial chaos for Mars entry mission

    Science.gov (United States)

    Huang, Yuechen; Li, Haiyang

    2018-06-01

    This paper presents the reliability-based sequential optimization (RBSO) method to settle the trajectory optimization problem with parametric uncertainties in entry dynamics for Mars entry mission. First, the deterministic entry trajectory optimization model is reviewed, and then the reliability-based optimization model is formulated. In addition, the modified sequential optimization method, in which the nonintrusive polynomial chaos expansion (PCE) method and the most probable point (MPP) searching method are employed, is proposed to solve the reliability-based optimization problem efficiently. The nonintrusive PCE method contributes to the transformation between the stochastic optimization (SO) and the deterministic optimization (DO) and to the approximation of trajectory solution efficiently. The MPP method, which is used for assessing the reliability of constraints satisfaction only up to the necessary level, is employed to further improve the computational efficiency. The cycle including SO, reliability assessment and constraints update is repeated in the RBSO until the reliability requirements of constraints satisfaction are satisfied. Finally, the RBSO is compared with the traditional DO and the traditional sequential optimization based on Monte Carlo (MC) simulation in a specific Mars entry mission to demonstrate the effectiveness and the efficiency of the proposed method.

  7. The influence of pre-deployment cognitive ability on post-traumatic stress disorder symptoms and trajectories

    DEFF Research Database (Denmark)

    Sørensen, Holger J; Andersen, Søren B; Karstoft, Karen-Inge

    2016-01-01

    (based on logical, verbal, numerical and spatial reasoning) were converted to a mean of 100 and with a standard deviation of 15. Results Higher pre-deployment cognitive ability scores were associated with lower risk of PTSD symptoms as assessed by the Posttraumatic Stress Disorder Checklist......-Civilian Version (PCL-C) 2.5 years post-deployment (OR=0.97; 95% CI 0.95-1.00) after adjustment for educational length, baseline PCL-C score and perceived war-zone stress. Compared to a resilient trajectory, a non-resilient relieved-worsening trajectory (high baseline mental symptoms, being symptom free during...

  8. Fatigue trajectories during the first 8 months after breast cancer diagnosis

    DEFF Research Database (Denmark)

    Bødtcher, Hanne; Bidstrup, Pernille Envold; Andersen, Ingelise

    2015-01-01

    Purpose The objective of this study was to identify distinct groups of fatigue trajectories among women with breast cancer and to evaluate whether age, anxiety symptoms, physical activity, and type of treatment were associated with belonging to the most adverse fatigue group. Methods Women...... scheduled for breast cancer surgery at Copenhagen University Hospital, Denmark, were consecutively invited to participate in the study (n = 424), resulting in 290 women included in the analyses. Semiparametric group-based mixture modeling was used to identify distinct trajectories of fatigue assessed......-fatigue group. Conclusions The results show that one-fifth of women with breast cancer experience continuously high fatigue up to 8 months after surgery and may have been more anxious and physically inactive. This knowledge is important in targeting interventions to women with fatigue throughout their treatment...

  9. Trajectories of Patient-Reported Health Status in Patients With an Implantable Cardioverter Defibrillator

    DEFF Research Database (Denmark)

    Mastenbroek, Mirjam H; Denollet, Johan; Versteeg, Henneke

    2015-01-01

    , no use of ACE inhibitors, psychotropic medication, negative affectivity, and type D personality were identified as independent determinants of poorer mental health status. In conclusion, the population with an ICD seems to be heterogeneous in terms of patient-reported physical and mental health status......To date, no study has assessed the course of patient-reported health status in patients with an implantable cardioverter defibrillator (ICD). Studying health status trajectories and their baseline determinants would permit the identification of patients at risk for poor health outcomes after ICD...... implantation. A combined cohort of 1,222 patients with an ICD (79% men; age = 61.4 [11.2] years) completed the 12-Item Short-Form Health Survey at baseline and 2 to 3 months and 12 to 14 months after implantation. Latent class analyses were used to identify trajectories and predictors of health status over...

  10. Paternal psychopathology and maternal depressive symptom trajectory during the first year postpartum

    Directory of Open Access Journals (Sweden)

    Randal G. Ross

    2013-02-01

    Full Text Available Understanding parental psychopathology interaction is important in preventing negative family outcomes. This study investigated the effect of paternal psychiatric history on maternal depressive symptom trajectory from birth to 12 months postpartum. Maternal Edinburgh Postpartum Depression screens were collected at 1, 6 and 12 months and fathers’ psychiatric diagnoses were assessed with the Structured Clinical Interview for DSM-IV from 64 families. There was not a significant difference in the trajectory of maternal depressive symptoms between mothers with partners with history of or a current psychiatric condition or those without a condition. However, mothers with partners with substance abuse history had higher levels of depressive symptoms relative to those affected by mood/anxiety disorders or those without a disorder. Our results call for a closer look at paternal history of substance abuse when treating postpartum maternal depression.

  11. Paternal psychopathology and maternal depressive symptom trajectory during the first year postpartum.

    Science.gov (United States)

    D'Anna-Hernandez, Kimberly L; Zerbe, Gary O; Hunter, Sharon K; Ross, Randal G

    2013-02-11

    Understanding parental psychopathology interaction is important in preventing negative family outcomes. This study investigated the effect of paternal psychiatric history on maternal depressive symptom trajectory from birth to 12 months postpartum. Maternal Edinburgh Postpartum Depression screens were collected at 1, 6 and 12 months and fathers' psychiatric diagnoses were assessed with the Structured Clinical Interview for DSM-IV from 64 families. There was not a significant difference in the trajectory of maternal depressive symptoms between mothers with partners with history of or a current psychiatric condition or those without a condition. However, mothers with partners with substance abuse history had higher levels of depressive symptoms relative to those affected by mood/anxiety disorders or those without a disorder. Our results call for a closer look at paternal history of substance abuse when treating postpartum maternal depression.

  12. Narcissism and newlywed marriage: Partner characteristics and marital trajectories.

    Science.gov (United States)

    Lavner, Justin A; Lamkin, Joanna; Miller, Joshua D; Campbell, W Keith; Karney, Benjamin R

    2016-04-01

    Despite narcissism's relation with interpersonal dysfunction, surprisingly little empirical research has been devoted to understanding narcissism's effect on intimate relationships in general or marital relationships in particular. The current study addressed this gap using longitudinal data from a community sample of 146 newlywed couples assessed 6 times over the first 4 years of marriage. First, we examined partner characteristics associated with higher levels of narcissism to determine the degree to which couples were matched on narcissism and related traits. Second, we examined how narcissism predicted the trajectory of marital quality over time, testing narcissism's association with initial levels of relationship functioning (the intercept) and changes in relationship functioning (the slope). Results indicated a small degree of homophily but otherwise no clear pattern of partner characteristics for individuals higher in narcissism. Hierarchical linear modeling indicated that wives' total narcissism and entitlement/exploitativeness scores predicted the slope of marital quality over time, including steeper declines in marital satisfaction and steeper increases in marital problems. Husbands' narcissism scores generally had few effects on their own marital quality or that of their wives. These findings are notable in indicating that the effects of personality characteristics on marital functioning may take some time to manifest themselves, even if they were present from early in the marriage. Future research into the mediating psychological and interpersonal processes that link wives' narcissism with poorer marital functioning over time would be valuable. (c) 2016 APA, all rights reserved).

  13. Contextual Risk Profiles and Trajectories of Adolescent Dating Violence Perpetration.

    Science.gov (United States)

    Reyes, H Luz McNaughton; Foshee, Vangie A; Markiewitz, Nathan; Chen, May S; Ennett, Susan T

    2018-04-09

    Social ecological and developmental system perspectives suggest that interactions among factors within and across multiple contexts (e.g., neighborhood, peer, family) must be considered in explaining dating violence perpetration. Yet, to date, most extant research on dating violence has focused on individual, rather than contextual predictors, and used variable-centered approaches that fail to capture the configurations of factors that may jointly explain involvement in dating violence. The current study used a person-centered approach, latent profile analysis, to identify key configurations (or profiles) of contextual risk and protective factors for dating violence perpetration across the neighborhood, school, friend and family contexts. We then examine the longitudinal associations between these contextual risk profiles, assessed during middle school, and trajectories of psychological and physical dating violence perpetration across grades 8 through 12. Five contextual risk profiles were identified: school, neighborhood, and family risk; school and family risk; school and friend risk; school and neighborhood risk; and low risk. The highest levels of psychological and physical perpetration across grades 8 through 12 were among adolescents in the profile characterized by high levels of school, neighborhood, and family risk. Results suggest that early interventions to reduce violence exposure and increase social regulation across multiple social contexts may be effective in reducing dating violence perpetration across adolescence.

  14. Chaotic Bohmian trajectories for stationary states

    International Nuclear Information System (INIS)

    Cesa, Alexandre; Martin, John; Struyve, Ward

    2016-01-01

    In Bohmian mechanics, the nodes of the wave function play an important role in the generation of chaos. However, so far, most of the attention has been on moving nodes; little is known about the possibility of chaos in the case of stationary nodes. We address this question by considering stationary states, which provide the simplest examples of wave functions with stationary nodes. We provide examples of stationary wave functions for which there is chaos, as demonstrated by numerical computations, for one particle moving in three spatial dimensions and for two and three entangled particles in two dimensions. Our conclusion is that the motion of the nodes is not necessary for the generation of chaos. What is important is the overall complexity of the wave function. That is, if the wave function, or rather its phase, has a complex spatial variation, it will lead to complex Bohmian trajectories and hence to chaos. Another aspect of our work concerns the average Lyapunov exponent, which quantifies the overall amount of chaos. Since it is very hard to evaluate the average Lyapunov exponent analytically, which is often computed numerically, it is useful to have simple quantities that agree well with the average Lyapunov exponent. We investigate possible correlations with quantities such as the participation ratio and different measures of entanglement, for different systems and different families of stationary wave functions. We find that these quantities often tend to correlate to the amount of chaos. However, the correlation is not perfect, because, in particular, these measures do not depend on the form of the basis states used to expand the wave function, while the amount of chaos does. (paper)

  15. Depressive vulnerabilities predict depression status and trajectories of depression over 1 year in persons with acute coronary syndrome.

    Science.gov (United States)

    Doyle, Frank; McGee, Hannah; Delaney, Mary; Motterlini, Nicola; Conroy, Ronán

    2011-01-01

    Depression is prevalent in patients hospitalized with acute coronary syndrome (ACS). We determined whether theoretical vulnerabilities for depression (interpersonal life events, reinforcing events, cognitive distortions, Type D personality) predicted depression, or depression trajectories, post-hospitalization. We followed 375 ACS patients who completed depression scales during hospital admission and at least once during three follow-up intervals over 1 year (949 observations). Questionnaires assessing vulnerabilities were completed at baseline. Logistic regression for panel/longitudinal data predicted depression status during follow-up. Latent class analysis determined depression trajectories. Multinomial logistic regression modeled the relationship between vulnerabilities and trajectories. Vulnerabilities predicted depression status over time in univariate and multivariate analysis, even when controlling for baseline depression. Proportions in each depression trajectory category were as follows: persistent (15%), subthreshold (37%), never depressed (48%). Vulnerabilities independently predicted each of these trajectories, with effect sizes significantly highest for the persistent depression group. Self-reported vulnerabilities - stressful life events, reduced reinforcing events, cognitive distortions, personality - measured during hospitalization can identify those at risk for depression post-ACS and especially those with persistent depressive episodes. Interventions should focus on these vulnerabilities. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Health-related quality of life and life satisfaction in colorectal cancer survivors: trajectories of adjustment.

    Science.gov (United States)

    Dunn, Jeff; Ng, Shu Kay; Breitbart, William; Aitken, Joanne; Youl, Pip; Baade, Peter D; Chambers, Suzanne K

    2013-03-14

    This longitudinal study describes the five year trajectories of health-related quality of life (HR-QOL) and life satisfaction in long term colorectal cancer survivors. A population-based sample of 1966 colorectal cancer survivors were surveyed at six time points from five months to five years post-diagnosis. Predictor variables were: socio-demographic variables, optimism; cancer threat appraisal; perceived social support. Quality of life was assessed with the Functional Assessment of Cancer Therapy-Colorectal (HR-QOL); and the Satisfaction with Life Scale. Growth mixture models were applied to identify trajectory classes and their predictors. Distinct adjustment trajectories were identified for HR-QOL and life satisfaction. Lower optimism, poorer social support, a more negative cognitive appraisal, and younger age were associated with poorer life satisfaction, while survivors with less than 8 years of education had higher life satisfaction. This pattern was similar for overall HR-QOL except that educational level was not a significant predictor and later stage disease and female gender emerged as related to poorer outcomes. One in five survivors reported poorer constant HR-QOL (19.2%) and a small group had poor life satisfaction (7.2%); 26.2% reported constant high HR-QOL and 48.8% had high constant life satisfaction. Socioeconomic disadvantage and remoteness of residence uniquely predicted poorer outcomes in the colorectal cancer specific HR-QOL sub domain. Although HR-QOL and subjective cognitive QOL share similar antecedents their trajectory patterns suggested they are distinct adjustment outcomes; with life satisfaction emerging as temporally stable phenomenon. Unique patterns of risk support suggest the need to account for heterogeneity in adjustment in longitudinal QOL studies with cancer survivors.

  17. Store separation trajectory predictions for maritime Search and Rescue (SAR)

    CSIR Research Space (South Africa)

    Akroyd, G

    2017-06-01

    Full Text Available tunnel testing, Computational Fluid Dynamics (CFD) nor Six Degree-of-Freedom (SDOF) trajectory simulations prior to flight testing. This might have been since the released stores were relatively light weight, the airspeeds low, and incidental contact...

  18. Probabilistic Modeling of Aircraft Trajectories for Dynamic Separation Volumes

    Science.gov (United States)

    Lewis, Timothy A.

    2016-01-01

    With a proliferation of new and unconventional vehicles and operations expected in the future, the ab initio airspace design will require new approaches to trajectory prediction for separation assurance and other air traffic management functions. This paper presents an approach to probabilistic modeling of the trajectory of an aircraft when its intent is unknown. The approach uses a set of feature functions to constrain a maximum entropy probability distribution based on a set of observed aircraft trajectories. This model can be used to sample new aircraft trajectories to form an ensemble reflecting the variability in an aircraft's intent. The model learning process ensures that the variability in this ensemble reflects the behavior observed in the original data set. Computational examples are presented.

  19. 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.

  20. Trajectory Clustering and an Application to Airspace Monitoring

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a framework aimed at monitoring the behavior of aircraft in a given airspace. Trajectories that constitute typical operations are determined and...

  1. GALILEO ORBITER V POS VENUS TRAJECTORY V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Galileo Orbiter 60 second sampled trajectory data from the Venus flyby in Venus Solar Orbital (VSO) coordinates. These data cover the interval 1990-02-09 00:00 to...

  2. 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.

  3. Neural Dynamic Trajectory Design for Reentry Vehicles (Preprint)

    National Research Council Canada - National Science Library

    Verma, Ajay; Xu, Peng; Vadakkeveedu, Kalyan; Mayer, Rick

    2007-01-01

    The next generation of reentry vehicles is envisioned to have onboard autonomous capability of real-time trajectory planning to provide capability of responsive launch and delivering payload anywhere...

  4. 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.

  5. 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.

  6. Trajectory Optimization Based on Multi-Interval Mesh Refinement Method

    Directory of Open Access Journals (Sweden)

    Ningbo Li

    2017-01-01

    Full Text Available In order to improve the optimization accuracy and convergence rate for trajectory optimization of the air-to-air missile, a multi-interval mesh refinement Radau pseudospectral method was introduced. This method made the mesh endpoints converge to the practical nonsmooth points and decreased the overall collocation points to improve convergence rate and computational efficiency. The trajectory was divided into four phases according to the working time of engine and handover of midcourse and terminal guidance, and then the optimization model was built. The multi-interval mesh refinement Radau pseudospectral method with different collocation points in each mesh interval was used to solve the trajectory optimization model. Moreover, this method was compared with traditional h method. Simulation results show that this method can decrease the dimensionality of nonlinear programming (NLP problem and therefore improve the efficiency of pseudospectral methods for solving trajectory optimization problems.

  7. A new trajectory concept for exploring the earth's geomagnetic tail

    Science.gov (United States)

    Farquhar, R. W.; Dunham, D. W.

    1981-01-01

    An innovative trajectory technique for a magnetotail mapping mission is described which can control the apsidal rotation of an elliptical earth orbit and keep its apogee segment inside the tail region. The required apsidal rotation rate of approximately 1 deg/day is achieved by using the moon to carry out a prescribed sequence of gravity-assist maneuvers. Apogee distances are alternately raised and lowered by the lunar-swingby maneuvers; several categories of the 'sun-synchronous' swingby trajectories are identified. The strength and flexibility of the new trajectory concept is demonstrated by using real-world simulations showing that a large variety of trajectory shapes can be used to explore the earth's geomagnetic tail between 60 and 250 R sub E.

  8. Computational Appliance for Rapid Prediction of Aircraft Trajectories, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Next generation air traffic management systems will be based to a greater degree on predicted trajectories of aircraft. Due to the iterative nature of future air...

  9. Parametric Approach to Trajectory Tracking Control of Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Shijie Zhang

    2013-01-01

    Full Text Available The mathematic description of the trajectory of robot manipulators with the optimal trajectory tracking problem is formulated as an optimal control problem, and a parametric approach is proposed for the optimal trajectory tracking control problem. The optimal control problem is first solved as an open loop optimal control problem by using a time scaling transform and the control parameterization method. Then, by virtue of the relationship between the optimal open loop control and the optimal closed loop control along the optimal trajectory, a practical method is presented to calculate an approximate optimal feedback gain matrix, without having to solve an optimal control problem involving the complex Riccati-like matrix differential equation coupled with the original system dynamics. Simulation results of 2-link robot manipulator are presented to show the effectiveness of the proposed method.

  10. A Framework for Autonomous Trajectory-Based Operations, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation proposed is a framework for autonomous Traffic Flow Management (TFM) under Trajectory Based Operations (TBO) for Unmanned Aerial Systems (UAS). The...

  11. A Method of Trajectory Design for Manned Asteroids Exploration

    Science.gov (United States)

    Gan, Q. B.; Zhang, Y.; Zhu, Z. F.; Han, W. H.; Dong, X.

    2014-11-01

    A trajectory optimization method of the nuclear propulsion manned asteroids exploration is presented. In the case of launching between 2035 and 2065, based on the Lambert transfer orbit, the phases of departure from and return to the Earth are searched at first. Then the optimal flight trajectory in the feasible regions is selected by pruning the flight sequences. Setting the nuclear propulsion flight plan as propel-coast-propel, and taking the minimal mass of aircraft departure as the index, the nuclear propulsion flight trajectory is separately optimized using a hybrid method. With the initial value of the optimized local parameters of each three phases, the global parameters are jointedly optimized. At last, the minimal departure mass trajectory design result is given.

  12. Real-Time Trajectory Generation for Autonomous Nonlinear Flight Systems

    National Research Council Canada - National Science Library

    Larsen, Michael; Beard, Randal W; McLain, Timothy W

    2006-01-01

    ... to mobile threats such as radar, jammers, and unfriendly aircraft. In Phase 1 of this STTR project, real-time path planning and trajectory generation techniques for two dimensional flight were developed and demonstrated in software simulation...

  13. Trajectory Planning and Walking Pattern Generation of Humanoid Robot Motion

    Directory of Open Access Journals (Sweden)

    Saeed Abdolshah

    2014-12-01

    Full Text Available Walking trajectory generation for a humanoid robot is a challenging control  issue. In this paper, a walking cycle has been recognized considering human motion, and nine simple steps were distinguished in a full step of walking which form motion trajectory, and generates a simplified ZMP motion formulation. This system was used in humanoid robot simulation motion and is achievable easily in walking steps of robot. A minimum DOFs humanoid robot has been considered and geometrical relationships between the robot links were presented by the Denavit-Hartenberg method. The inverse kinematics equations have been solved regarding to extracted ZMP trajectory formula, and constraints in different steps. As a result; angular velocity, acceleration and power of motors were obtained using the relationships and Jacobin. At each step, extracted data were applied on simulated robot in Matlab, and Visual Nastran software. Zero moment point trajectory was evaluated in simulation environment.

  14. Trajectory planning and optimal tracking for an industrial mobile robot

    Science.gov (United States)

    Hu, Huosheng; Brady, J. Michael; Probert, Penelope J.

    1994-02-01

    This paper introduces a unified approach to trajectory planning and tracking for an industrial mobile robot subject to non-holonomic constraints. We show (1) how a smooth trajectory is generated that takes into account the constraints from the dynamic environment and the robot kinematics; and (2) how a general predictive controller works to provide optimal tracking capability for nonlinear systems. The tracking performance of the proposed guidance system is analyzed by simulation.

  15. Sliding Mode Control for Trajectory Tracking of an Intelligent Wheelchair

    Directory of Open Access Journals (Sweden)

    Razvan SOLEA

    2009-12-01

    Full Text Available This paper deal with a robust sliding-mode trajectory tracking controller, fornonholonomic wheeled mobile robots and its experimental evaluation by theimplementation in an intelligent wheelchair (RobChair. The proposed control structureis based on two nonlinear sliding surfaces ensuring the tracking of the three outputvariables, with respect to the nonholonomic constraint. The performances of theproposed controller for the trajectory planning problem with comfort constraint areverified through the real time acceleration provided by an inertial measurement unit.

  16. Optimal Lunar Landing Trajectory Design for Hybrid Engine

    OpenAIRE

    Cho, Dong-Hyun; Kim, Donghoon; Leeghim, Henzeh

    2015-01-01

    The lunar landing stage is usually divided into two parts: deorbit burn and powered descent phases. The optimal lunar landing problem is likely to be transformed to the trajectory design problem on the powered descent phase by using continuous thrusters. The optimal lunar landing trajectories in general have variety in shape, and the lunar lander frequently increases its altitude at the initial time to obtain enough time to reduce the horizontal velocity. Due to the increment in the altitude,...

  17. Lunar Landing Trajectory Design for Onboard Hazard Detection and Avoidance

    Science.gov (United States)

    Paschall, Steve; Brady, Tye; Sostaric, Ron

    2009-01-01

    The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project is developing the software and hardware technology needed to support a safe and precise landing for the next generation of lunar missions. ALHAT provides this capability through terrain-relative navigation measurements to enhance global-scale precision, an onboard hazard detection system to select safe landing locations, and an Autonomous Guidance, Navigation, and Control (AGNC) capability to process these measurements and safely direct the vehicle to a landing location. This paper focuses on the key trajectory design issues relevant to providing an onboard Hazard Detection and Avoidance (HDA) capability for the lander. Hazard detection can be accomplished by the crew visually scanning the terrain through a window, a sensor system imaging the terrain, or some combination of both. For ALHAT, this hazard detection activity is provided by a sensor system, which either augments the crew s perception or entirely replaces the crew in the case of a robotic landing. Detecting hazards influences the trajectory design by requiring the proper perspective, range to the landing site, and sufficient time to view the terrain. Following this, the trajectory design must provide additional time to process this information and make a decision about where to safely land. During the final part of the HDA process, the trajectory design must provide sufficient margin to enable a hazard avoidance maneuver. In order to demonstrate the effects of these constraints on the landing trajectory, a tradespace of trajectory designs was created for the initial ALHAT Design Analysis Cycle (ALDAC-1) and each case evaluated with these HDA constraints active. The ALHAT analysis process, described in this paper, narrows down this tradespace and subsequently better defines the trajectory design needed to support onboard HDA. Future ALDACs will enhance this trajectory design by balancing these issues and others in an overall system

  18. 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.

  19. Trajectories in higher education: ProUni in focus

    OpenAIRE

    Felicetti,Vera Lucia; Cabrera,Alberto F.

    2017-01-01

    Abstract Trajectories in higher education and the University for All Program (ProUni) are the central theme of this paper. The research question was: To what extent were some factors experienced during university difficulties in the academic trajectory of ProUni and non-ProUni graduates? The approach was quantitative with an explanatory goal. Descriptive and inferential statistics were used in the data analysis. The research subjects were 197 higher education graduates from a Southern Brazil ...

  20. Calculation of trajectory parameters of long pass in basketball.

    Directory of Open Access Journals (Sweden)

    Charikova K.M.

    2011-08-01

    Full Text Available Values of a ball's flight trajectory parameters depending on a distance of long pass, a corner of a ball's start and height of a throwing point are submitted in article. Coordinates of reference points installation for training to long pass with an optimum trajectory of a ball's flight are designed. Requirements to simulators design are determined. Corners of ball's long pass performance in various game situations are recommended.

  1. 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.

  2. 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

  3. Illness trajectories in patients with amyotrophic lateral sclerosis: How illness progression is related to life narratives and interpersonal relationships.

    Science.gov (United States)

    Cipolletta, Sabrina; Gammino, Giorgia Rosamaria; Palmieri, Arianna

    2017-12-01

    To identify illness trajectories in amyotrophic lateral sclerosis by analysing personal, social and functional dimensions related to amyotrophic lateral sclerosis progression. Previous studies have considered some psychological distinct variables that may moderate illness progression, but no research has combined an extensive qualitative understanding of amyotrophic lateral sclerosis patients' psychological characteristics and illness progression. A mixed-methods approach was used to combine quantitative and qualitative measures. Illness progression was assessed through a longitudinal design. Eighteen patients with amyotrophic lateral sclerosis attending a Neurology Department in northern Italy participated in the study. Semi-structured interviews to explore personal experience, and dependency grids to assess the distribution of dependency; ALSFRS-R and neuropsychological screening were, respectively, used to measure physical and cognitive impairment. To assess the progression of the disease, ALSFRS-R was re-administered after 8 months and mortality rate was considered. Data were analysed using the grounded theory approach. Illness progression changed according to the perception of the disease, the trust placed in medical care, self-construction and the distribution of dependency. Based on these categories, cases that had similar experiences were grouped, and four illness trajectories were identified: aggressiveness, threat, constriction and guilt. The findings suggest that it is possible to identify different illness trajectories in amyotrophic lateral sclerosis. Personalised intervention strategies may be construed based on the different trajectories identified. © 2017 John Wiley & Sons Ltd.

  4. 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.

  5. 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.

  6. Quantum trajectory analysis of multimode subsystem-bath dynamics.

    Science.gov (United States)

    Wyatt, Robert E; Na, Kyungsun

    2002-01-01

    The dynamics of a swarm of quantum trajectories is investigated for systems involving the interaction of an active mode (the subsystem) with an M-mode harmonic reservoir (the bath). Equations of motion for the position, velocity, and action function for elements of the probability fluid are integrated in the Lagrangian (moving with the fluid) picture of quantum hydrodynamics. These fluid elements are coupled through the Bohm quantum potential and as a result evolve as a correlated ensemble. Wave function synthesis along the trajectories permits an exact description of the quantum dynamics for the evolving probability fluid. The approach is fully quantum mechanical and does not involve classical or semiclassical approximations. Computational results are presented for three systems involving the interaction on an active mode with M=1, 10, and 15 bath modes. These results include configuration space trajectory evolution, flux analysis of the evolving ensemble, wave function synthesis along trajectories, and energy partitioning along specific trajectories. These results demonstrate the feasibility of using a small number of quantum trajectories to obtain accurate quantum results on some types of open quantum systems that are not amenable to standard quantum approaches involving basis set expansions or Eulerian space-fixed grids.

  7. Creating drag and lift curves from soccer trajectories

    Science.gov (United States)

    Goff, John Eric; Kelley, John; Hobson, Chad M.; Seo, Kazuya; Asai, Takeshi; Choppin, S. B.

    2017-07-01

    Trajectory analysis is an alternative to using wind tunnels to measure a soccer ball’s aerodynamic properties. It has advantages over wind tunnel testing such as being more representative of game play. However, previous work has not presented a method that produces complete, speed-dependent drag and lift coefficients. Four high-speed cameras in stereo-calibrated pairs were used to measure the spatial co-ordinates for 29 separate soccer trajectories. Those trajectories span a range of launch speeds from 9.3 to 29.9 m s-1. That range encompasses low-speed laminar flow of air over a soccer ball, through the drag crises where air flow is both laminar and turbulent, and up to high-speed turbulent air flow. Results from trajectory analysis were combined to give speed-dependent drag and lift coefficient curves for the entire range of speeds found in the 29 trajectories. The average root mean square error between the measured and modelled trajectory was 0.028 m horizontally and 0.034 m vertically. The drag and lift crises can be observed in the plots of drag and lift coefficients respectively.

  8. Solar sail time-optimal interplanetary transfer trajectory design

    International Nuclear Information System (INIS)

    Gong Shengpin; Gao Yunfeng; Li Junfeng

    2011-01-01

    The fuel consumption associated with some interplanetary transfer trajectories using chemical propulsion is not affordable. A solar sail is a method of propulsion that does not consume fuel. Transfer time is one of the most pressing problems of solar sail transfer trajectory design. This paper investigates the time-optimal interplanetary transfer trajectories to a circular orbit of given inclination and radius. The optimal control law is derived from the principle of maximization. An indirect method is used to solve the optimal control problem by selecting values for the initial adjoint variables, which are normalized within a unit sphere. The conditions for the existence of the time-optimal transfer are dependent on the lightness number of the sail and the inclination and radius of the target orbit. A numerical method is used to obtain the boundary values for the time-optimal transfer trajectories. For the cases where no time-optimal transfer trajectories exist, first-order necessary conditions of the optimal control are proposed to obtain feasible solutions. The results show that the transfer time decreases as the minimum distance from the Sun decreases during the transfer duration. For a solar sail with a small lightness number, the transfer time may be evaluated analytically for a three-phase transfer trajectory. The analytical results are compared with previous results and the associated numerical results. The transfer time of the numerical result here is smaller than the transfer time from previous results and is larger than the analytical result.

  9. 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.

  10. 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.

  11. Variation in narrative identity is associated with trajectories of mental health over several years.

    Science.gov (United States)

    Adler, Jonathan M; Turner, Ariana F; Brookshier, Kathryn M; Monahan, Casey; Walder-Biesanz, Ilana; Harmeling, Luke H; Albaugh, Michelle; McAdams, Dan P; Oltmanns, Thomas F

    2015-03-01

    This article presents 2 longitudinal studies designed to assess the relationship between variability in narrative identity and trajectories of mental health over several years. In Study 1, core scenes from 89 late-mid-life adults' life stories were assessed for several narrative themes. Participants' mental health and physical health were assessed concurrently with the narratives and annually for the subsequent 4 years. Concurrent analyses indicated that the themes of agency, redemption, and contamination were significantly associated with mental health. Longitudinal analyses indicated that these same 3 themes were significantly associated with participants' trajectories of mental health over the course of 4 years. Exploratory analyses indicated that narratives of challenging experiences may be central to this pattern of results. In Study 2, similar longitudinal analyses were conducted on a sample of 27 late-mid-life adults who received a major physical illness diagnosis between the baseline assessment and 6 months later and a matched sample of 27 control participants who remained healthy throughout the study. Participants' mental health and physical health were assessed every 6 months for 2 years. In this study, the themes of agency, communion, redemption, and contamination in participants' life narratives collected at baseline (before any participant became sick) were significantly associated with mental health in the group of participants who went on to receive a medical diagnosis, but not in the control group. Taken together, the results of these 2 studies indicate that the way an individual constructs personal narratives may impact his or her trajectory of mental health over time. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  12. Variation in Narrative Identity is Associated with Trajectories of Mental Health over Several Years

    Science.gov (United States)

    Adler, Jonathan M.; Turner, Ariana F.; Brookshier, Kathryn M.; Monahan, Casey; Walder-Biesanz, Ilana; Harmeling, Luke H.; Albaugh, Michelle; McAdams, Dan P.; Oltmanns, Thomas F.

    2015-01-01

    This paper presents two longitudinal studies designed to assess the relationship between variability in narrative identity and trajectories of mental health over several years. In Study 1, core scenes from 89 late-mid-life adults’ life stories were assessed for several narrative themes. Participants’ mental health and physical health were assessed concurrently with the narratives and once a year for the subsequent four years. Concurrent analyses indicated that the themes of agency, redemption, and contamination were significantly associated with mental (but not physical) health. Longitudinal analyses indicated that these same three themes were significantly associated with participants’ trajectories of mental health over the course of four years. Exploratory analyses indicated that narratives of challenging experiences may be central to this pattern of results. In Study 2, similar longitudinal analyses were conducted on a sample of 27 late-mid-life adults who received a major physical illness diagnosis between the baseline assessment and six months later and a matched sample of 27 control participants who remained healthy throughout the study. Participants’ mental health and physical health were assessed every six months for two years. In this tightly controlled study, the themes of agency, communion, redemption, and contamination in participants’ life narratives collected at Baseline (before any participant got sick) were significantly positively associated with mental health in the group of participants who went on to receive a medical diagnosis, but not in the control group. Taken together, the results of these two studies indicate that the way an individual constructs personal narratives may impact his or her trajectory of mental health over time. PMID:25751718

  13. 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

  14. Lattice QCD Thermodynamics First 5000 Trajectories

    International Nuclear Information System (INIS)

    Soltz, R; Gupta, R

    2007-01-01

    These results represent the first LQCD analysis for approximately 5000 trajectories with each of the p4rhmc and milc codes, with some of the lower temperature runs having fewer. Both runs were for lattice dimensions of 32 3 x8. Some 32 4 T=0 jobs were also run for p4rhmc. The p4 calculation was performed with v2.0 QMP( ) MPI.X (semi-optimized p4 code using qmp over mpi) and milc version of the su3 rhmc susc eos executable dated Mar 1, 2007 on ubgl in the /usr/gapps/hip/qcd/milc/bin subdirectory (svn revision 28). As with previous runs, calculations were performed along lines of constant physics, with the light quark masses 2-3 times their physics values and the strange quark mass set by m ud = 0.1m s . Job submissions were performed using a new subSet.pl job submission script that locates current jobs and submits additional jobs with the same beta value as pending. Note that after reaching a limit of about 35 jobs subsequent submissions are delayed and will not be submitted directly from that state. The job submission script was used to submit revised versions of the milc and p4rhmc csh scripts. Initial thermalized lattices for each code were also for milc (taken from the firstPhys runs), but the p4rhmc runs include thermalization. The only modifications for running on BG/L were to the directory names and the mT parameter which determines job durations (24 hrs on BG/L vs. 4 hrs on ubgl). All finite temperature jobs were submitted to the 512 node partitions, and all T=0 runs were submitted to 2048 node partitions. The set of runs was plagued by filesystem errors on lscratch1 and lscratcH 2 . Many jobs had to be reset (deleting the most recent output file for milc and/or lattice for p4) and resubmitted. The analysis was performed with a new set of scripts that produced a more condensed output for scanning. All scans were verified with checksums, which have been retained in the output along with the line numbers. All lattices, log files, and job submission scripts

  15. Depression symptom trajectories and associated risk factors among adolescents in Chile.

    Directory of Open Access Journals (Sweden)

    Lexine A Stapinski

    Full Text Available Adolescence is a key period for studying the development of depression, with studies in Europe and North America showing a pattern of elevated risk that begins in early adolescence and continues to increase as adolescents age. Few studies have examined the course of adolescent depression and associated risk factors in low and middle-income countries. This longitudinal cohort study examined depression symptom trajectories and risk factors in a sample of socio-economically disadvantaged adolescents in Chile (n = 2,508. Data were collected over an 18-month period as part of a clinical trial for secondary students aged 12 to 18 (median age 14. Clinical levels of depression were prevalent in this sample at baseline (35% for girls and 28% for boys; yet latent growth models of symptom trajectories revealed a pattern of decreasing symptoms over time. There was evidence of an anxiety-depression developmental pathway for girls, with elevated anxiety levels initially predicting poorer depression outcomes later on. Poor problem-solving skills were associated with initial depression levels but did not predict the course of depressive symptoms. Critically, the declining symptom trajectories raise important methodological issues regarding the effects of repeated assessment in longitudinal studies.

  16. Attention Deficit Hyperactivity Disorder symptoms and smoking trajectories: race and gender differences.

    Science.gov (United States)

    Lee, Chien-Ti; Clark, Trenette T; Kollins, Scott H; McClernon, F Joseph; Fuemmeler, Bernard F

    2015-03-01

    This study examined the influence of Attention Deficit Hyperactivity Disorder (ADHD) symptoms severity and directionality (hyperactive-impulsive symptoms relative to inattentive symptoms) on trajectories of the probability of current (past month) smoking and the number of cigarettes smoked from age 13 to 32. Racial and gender differences in the relationship of ADHD symptoms and smoking trajectories were also assessed. A subsample of 9719 youth (54.5% female) was drawn from the National Longitudinal Study of Adolescent to Adult Health (Add Health). Cohort sequential design and zero-inflated Poisson (ZIP) latent growth modeling were used to estimate the relationship between ADHD directionality and severity on smoking development. ADHD severity's effect on the likelihood of ever smoking cigarettes at the intercept (age 13) had a greater impact on White males than other groups. ADHD severity also had a stronger influence on the initial number of cigarettes smoked at age 13 among Hispanic participants. The relationships between ADHD directionality (hyperactive-impulsive symptoms relative to inattentive symptoms) and a higher number of cigarettes smoked at the intercept were stronger among Hispanic males than others. Gender differences manifested only among Whites. ADHD severity and directionality had unique effects on smoking trajectories. Our results also highlight that the risk of ADHD symptoms may differ by race and gender. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Depression symptom trajectories and associated risk factors among adolescents in Chile.

    Science.gov (United States)

    Stapinski, Lexine A; Montgomery, Alan A; Heron, Jon; Jerrim, John; Vignoles, Anna; Araya, Ricardo

    2013-01-01

    Adolescence is a key period for studying the development of depression, with studies in Europe and North America showing a pattern of elevated risk that begins in early adolescence and continues to increase as adolescents age. Few studies have examined the course of adolescent depression and associated risk factors in low and middle-income countries. This longitudinal cohort study examined depression symptom trajectories and risk factors in a sample of socio-economically disadvantaged adolescents in Chile (n = 2,508). Data were collected over an 18-month period as part of a clinical trial for secondary students aged 12 to 18 (median age 14). Clinical levels of depression were prevalent in this sample at baseline (35% for girls and 28% for boys); yet latent growth models of symptom trajectories revealed a pattern of decreasing symptoms over time. There was evidence of an anxiety-depression developmental pathway for girls, with elevated anxiety levels initially predicting poorer depression outcomes later on. Poor problem-solving skills were associated with initial depression levels but did not predict the course of depressive symptoms. Critically, the declining symptom trajectories raise important methodological issues regarding the effects of repeated assessment in longitudinal studies.

  18. U.S. Immigration Policy Regimes and Physical Disability Trajectories Among Mexico-U.S. Immigrants.

    Science.gov (United States)

    Mueller, Collin W; Bartlett, Bryce J

    2017-03-21

    Although immigration policies have shifted dramatically over the course of U.S. history, few have examined their role as a source of health heterogeneity among immigrants. We address this gap by evaluating whether exposure to U.S. Immigration Policy Regimes (IPRs) corresponds with later-life disability disparities among Mexico-U.S. migrant women and men, and assess the degree to which observed differences may also be associated with immigration policies and occupational composition. We analyze 8 waves of data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly (3,044 individuals and 14,474 observations from 1993/1994-2013). Using hierarchical linear models, we estimate trajectories of physical disability associated with gender, occupation, and IPR. We find differences in disability trajectories by IPR. Associations are not different between men and women, and are not mediated by occupational composition. We also observe an additive effect for certain occupations among women, but not among men. Findings demonstrate that exposure to different IPRs is associated with disparate disability trajectories among Mexico-U.S. migrants. Future research is needed to contextualize the role of IPRs amid other mechanisms of gendered racialization that powerfully contribute to cumulative health differences across the life course. © The Author 2017. 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.

  19. Differences in center of pressure trajectory between normal and steppage gait

    Science.gov (United States)

    Jamshidi, Nima; Rostami, Mostafa; Najarian, Siamak; Menhaj, Mohammad Bagher; Saadatnia, Mohammad; Salami, Firooz

    2010-01-01

    BACKGROUND: This pilot study aimed to assess the differences in center of pressure trajectory in neuropathic patients with steppage gait. Steppage gait has previously been evaluated by several biomechanical methods, but plantar pressure distribution has been much less studied. The purpose of this study was to analyze the changes in center of pressure trajectory using a force plate. METHODS: The steppage gait group was selected from the patients using drop foot brace (25 male) and the control group was selected from Isfahan university students (20 male). They walked at self- selected speed at a mean of ten trials (+2) to collect the center of pressure using a force plate. Center of pressure patterns were categorized into four patterns based on the center of pressure displacement magnitude (spatial features) through time (temporal features) when the longitudinal axis of the insole was plotted as the Y- axis and the transverse axis of the insole as X- axis during stance phase. RESULTS: The horizontal angle measured from center of pressure linear regression was positive in the control group (4.6 ± 2.4) (p < 0.005), but negative in the patient group (- 2.3 ± 1.6) (p < 0.005). CONCLUSIONS: The finding of this research measured center of pressure trajectory in steppage gait over time, which is useful for designing better shoe sole and also orthopaedic device and better understanding of stability in patients with drop foot. PMID:21526056

  20. Eye movements and manual interception of ballistic trajectories: effects of law of motion perturbations and occlusions.

    Science.gov (United States)

    Delle Monache, Sergio; Lacquaniti, Francesco; Bosco, Gianfranco

    2015-02-01

    Manual interceptions are known to depend critically on integration of visual feedback information and experience-based predictions of the interceptive event. Within this framework, coupling between gaze and limb movements might also contribute to the interceptive outcome, since eye movements afford acquisition of high-resolution visual information. We investigated this issue by analyzing subjects' head-fixed oculomotor behavior during manual interceptions. Subjects moved a mouse cursor to intercept computer-generated ballistic trajectories either congruent with Earth's gravity or perturbed with weightlessness (0 g) or hypergravity (2 g) effects. In separate sessions, trajectories were either fully visible or occluded before interception to enforce visual prediction. Subjects' oculomotor behavior was classified in terms of amounts of time they gazed at different visual targets and of overall number of saccades. Then, by way of multivariate analyses, we assessed the following: (1) whether eye movement patterns depended on targets' laws of motion and occlusions; and (2) whether interceptive performance was related to the oculomotor behavior. First, we found that eye movement patterns depended significantly on targets' laws of motion and occlusion, suggesting predictive mechanisms. Second, subjects coupled differently oculomotor and interceptive behavior depending on whether targets were visible or occluded. With visible targets, subjects made smaller interceptive errors if they gazed longer at the mouse cursor. Instead, with occluded targets, they achieved better performance by increasing the target's tracking accuracy and by avoiding gaze shifts near interception, suggesting that precise ocular tracking provided better trajectory predictions for the interceptive response.

  1. Modeling the Nature of Grammar and Vocabulary Trajectories From Prekindergarten to Third Grade.

    Science.gov (United States)

    Jiang, Hui; Logan, Jessica A; Jia, Rongfang

    2018-04-17

    This study investigated the longitudinal development of 2 important contributors to reading comprehension, grammar, and vocabulary skills. The primary interest was to examine the trajectories of the 2 skill areas from preschool to 3rd grade. The study involved a longitudinal sample of 420 children from 4 sites. Language skills, including grammar and vocabulary, were assessed annually with multiple measures. Multivariate latent growth curve modeling was used to examine the developmental trajectories of grammar and vocabulary, to test the correlation between the 2 domains, and to investigate the effects of demographic predictors on language growth. Results showed that both grammar and vocabulary exhibited decelerating growth from preschool to Grade 2. In Grade 3, grammar growth further flattened, whereas vocabulary continued to grow stably. Growth of vocabulary and grammar were positively correlated. Demographic characteristics, such as child gender and family socioeconomic status, were found to predict the intercept but not the slope of the growth trajectories. Children's growth in grammar skills is differentiated in a number of important ways from their growth in vocabulary skills. Results of this study suggest the need to differentiate these dimensions of language when seeking to closely examine growth from preschool to primary grades.

  2. Lifecourse socioeconomic position and 16 year body mass index trajectories: differences by race and sex.

    Science.gov (United States)

    Insaf, Tabassum Z; Shaw, Benjamin A; Yucel, Recai M; Chasan-Taber, Lisa; Strogatz, David S

    2014-10-01

    The aim of this study is to evaluate the association between lifecourse socioeconomic position (SEP) and changes in body mass index (BMI), and assess disparities in these associations across racial/ethnic groups. With longitudinal data from 4 waves of the Americans' Changing Lives Study (1986-2002), we employed mixed-effects modeling to estimate BMI trajectories for 1174 Blacks and 2323 White adults. We also estimated associations between these trajectories and lifecourse SEP variables, including father's education, perceived childhood SEP, own education, income, wealth, and financial security. Blacks had higher baseline BMIs, and steeper increases in BMI, compared to Whites. Childhood SEP, as measured by high father's education, was associated with lower baseline BMI among Whites. High education was associated with a lower baseline BMI within both race and sex categories. Income had contrasting effects among men and women. Higher income was associated with higher BMI only among males. Associations between indicators of SEP and BMI trajectories were only found for Whites. Our study demonstrates that lifecourse SEP may influence adult BMI differently within different racial and sex groups. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Differences in center of pressure trajectory between normal and steppage gait

    Directory of Open Access Journals (Sweden)

    Nima Jamshidi

    2010-01-01

    Full Text Available Background: This pilot study aimed to assess the differences in center of pressure trajectory in neuropathic patients with steppage gait. Steppage gait has previously been evaluated by several biomechanical methods, but plantar pressure distribution has been much less studied. The purpose of this study was to analyze the changes in center of pressure tra-jectory using a force plate. Methods: The steppage gait group was selected from the patients using drop foot brace (25 male and the control group was selected from Isfahan university students (20 male. They walked at self- selected speed at a mean of ten tri-als (+2 to collect the center of pressure using a force plate. Center of pressure patterns were categorized into four pat-terns based on the center of pressure displacement magnitude (spatial features through time (temporal features when the longitudinal axis of the insole was plotted as the Y- axis and the transverse axis of the insole as X- axis during stance phase. Results: The horizontal angle measured from center of pressure linear regression was positive in the control group (4.6 ± 2.4 (p < 0.005, but negative in the patient group (- 2.3 ± 1.6 (p < 0.005. Conclusions: The finding of this research measured center of pressure trajectory in steppage gait over time, which is useful for designing better shoe sole and also orthopaedic device and better understanding of stability in patients with drop foot.

  4. Developmental trajectories of resting EEG power: an endophenotype of autism spectrum disorder.

    Directory of Open Access Journals (Sweden)

    Adrienne L Tierney

    Full Text Available Current research suggests that autism spectrum disorder (ASD is characterized by asynchronous neural oscillations. However, it is unclear whether changes in neural oscillations represent an index of the disorder or are shared more broadly among both affected and unaffected family members. Additionally, it remains unclear how early these differences emerge in development and whether they remain constant or change over time. In this study we examined developmental trajectories in spectral power in infants at high- or low-risk for ASD. Spectral power was extracted from resting EEG recorded over frontal regions of the scalp when infants were 6, 9, 12, 18 and 24 months of age. We used multilevel modeling to assess change over time between risk groups in the delta, theta, low alpha, high alpha, beta, and gamma frequency bands. The results indicated that across all bands, spectral power was lower in high-risk infants as compared to low-risk infants at 6-months of age. Furthermore high-risk infants showed different trajectories of change in spectral power in the subsequent developmental window indicating that not only are the patterns of change different, but that group differences are dynamic within the first two years of life. These findings remained the same after removing data from a subset of participants who displayed ASD related behaviors at 24 or 36 months. These differences in the nature of the trajectories of EEG power represent important endophenotypes of ASD.

  5. Trajectories of dating violence: Differences by sexual minority status and gender.

    Science.gov (United States)

    Martin-Storey, Alexa; Fromme, Kim

    2016-06-01

    The purpose of this study was to examine how sexual minority status (as assessed using both identity and behavior) was associated with trajectories of dating violence. University students from a large Southwestern university completed questions on their sexual minority identity, the gender of their sexual partners, and about experiences of dating violence for six consecutive semesters (N = 1942). Latent growth curve modeling indicated that generally, trajectories of dating violence were stable across study participation. Sexual minority identity was associated with higher initial levels of dating violence at baseline, but also with greater decreases in dating violence across time. These differences were mediated by number of sexual partners. Having same and other-sex sexual partners was associated with higher levels of dating violence at baseline, and persisted in being associated with higher levels over time. No significant gender difference was observed regarding trajectories of dating violence. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  6. Body Mass Index Trajectories and Healthcare Utilization in Young and Middle-aged Adults.

    Science.gov (United States)

    Elrashidi, Muhamad Y; Jacobson, Debra J; St Sauver, Jennifer; Fan, Chun; Lynch, Brian A; Rutten, Lila J Finney; Ebbert, Jon O

    2016-01-01

    The obesity epidemic is a significant public health issue with adverse impact on health and costs. Applying a life-course perspective to obesity may advance our understanding of the influence of obesity over time on patterns of healthcare utilization in young and middle-aged United States (US) adults.We identified baseline body mass index (BMI) and BMI trajectories, and assessed their association with outpatient visits, emergency department (ED) visits, and hospitalizations in a well-defined population of young and middle-aged US adults.Using the Rochester Epidemiology Project resources, we conducted a retrospective cohort study of adults (N = 23,254) aged 18 to 44 years, with at least 3 BMI measurements, residing in Olmsted County, MN from January 1, 2005 through December 31, 2012.We observed that 27.5% of the population was obese. Four BMI trajectories were identified. Compared to under/normal weight, obese class III adults had higher risk of outpatient visits (adjusted rate ratio [RR], 1.86; 95% confidence intervals [CIs], 1.67-2,08), ED visits (adjusted RR, 3.02; 95% CI, 2.74-3.34), and hospitalizations (adjusted RR, 1.67; 95% CI, 1.59-1.75). BMI trajectory was positively associated with ED visits after adjustment for age, sex, race, and Charlson Comorbidity Index (P young and middle-aged US adults, baseline BMI is positively associated with outpatient visits, ED visits, and hospitalizations, while BMI trajectory is positively associated with ED visits. These findings extend our understanding of the longitudinal influence of obesity on healthcare utilization in early to mid-adulthood.

  7. Trajectory optimization for dynamic couch rotation during volumetric modulated arc radiotherapy

    Science.gov (United States)

    Smyth, Gregory; Bamber, Jeffrey C.; Evans, Philip M.; Bedford, James L.

    2013-11-01

    Non-coplanar radiation beams are often used in three-dimensional conformal and intensity modulated radiotherapy to reduce dose to organs at risk (OAR) by geometric avoidance. In volumetric modulated arc radiotherapy (VMAT) non-coplanar geometries are generally achieved by applying patient couch rotations to single or multiple full or partial arcs. This paper presents a trajectory optimization method for a non-coplanar technique, dynamic couch rotation during VMAT (DCR-VMAT), which combines ray tracing with a graph search algorithm. Four clinical test cases (partial breast, brain, prostate only, and prostate and pelvic nodes) were used to evaluate the potential OAR sparing for trajectory-optimized DCR-VMAT plans, compared with standard coplanar VMAT. In each case, ray tracing was performed and a cost map reflecting the number of OAR voxels intersected for each potential source position was generated. The least-cost path through the cost map, corresponding to an optimal DCR-VMAT trajectory, was determined using Dijkstra’s algorithm. Results show that trajectory optimization can reduce dose to specified OARs for plans otherwise comparable to conventional coplanar VMAT techniques. For the partial breast case, the mean heart dose was reduced by 53%. In the brain case, the maximum lens doses were reduced by 61% (left) and 77% (right) and the globes by 37% (left) and 40% (right). Bowel mean dose was reduced by 15% in the prostate only case. For the prostate and pelvic nodes case, the bowel V50 Gy and V60 Gy were reduced by 9% and 45% respectively. Future work will involve further development of the algorithm and assessment of its performance over a larger number of cases in site-specific cohorts.

  8. Nestedness and successional trajectories of macroinvertebrate assemblages in man-made wetlands.

    Science.gov (United States)

    Ruhí, Albert; Boix, Dani; Gascón, Stéphanie; Sala, Jordi; Quintana, Xavier D

    2013-02-01

    Current successional models, primarily those based on floral succession, propose several distinct trajectories based on the integration of two key hypotheses from succession theory: convergence versus divergence in species composition among successional sites, and progression towards versus deviation from a desired reference state. We applied this framework to faunal succession, including differential colonization between active and passive dispersers, and the nested patterns generated as a consequence of this peculiarity. Nine man-made wetlands located in three different areas, from 0-3 years from wetland creation, were assessed. In addition, 91 wetlands distributed throughout the region were used as references for natural macroinvertebrate communities. We predicted the following: (1) highly nested structures in pioneering assemblages will decrease to lower mid-term values due to a shift from active pioneering taxa to passive disperser ones; (2) passive idiosyncratic taxa will elicit divergent successional trajectories among areas; (3) the divergent trajectories will provoke lower local and higher regional diversity values in the mid-term assemblages than in pioneer assemblages. Our results were largely congruent with hypotheses (1) and (2), diverging from the anticipated patterns only in the case of the temporary wetlands area. However, overall diversity trends based on hypothesis (3) did not follow the expected pattern. The divergent successional trajectories did not compensate for regional biodiversity losses that occurred as a consequence of pioneering colonizer decline over time. Consequently, we suggest reconsidering wetland construction for mitigation purposes within mid-term time frames (≤ 3 years). Wetlands may not offset, within this temporal scenario, regional biodiversity loss because the ecosystem may not support idiosyncratic taxa from natural wetlands.

  9. Effect of Sibling Birth on BMI Trajectory in the First 6 Years of Life.

    Science.gov (United States)

    Mosli, Rana H; Kaciroti, Niko; Corwyn, Robert F; Bradley, Robert H; Lumeng, Julie C

    2016-04-01

    This study examined the longitudinal association between birth of a sibling and changes in body mass index z-score (BMIz) trajectory during the first 6 years of life. Children (n = 697) were recruited across 10 sites in the United States at the time of birth. Sibship composition was assessed every 3 months. Anthropometry was completed when the child was age 15 months, 24 months, 36 months, 54 months, and in first grade. Children were classified based on the timing of their sibling's birth. A piecewise quadratic regression model adjusted for potential confounders examined the association of the birth of a sibling with subsequent BMIz trajectory. Children whose sibling was born when they were 24 to 36 months or 36 to 54 months old, compared with children who did not experience the birth of a sibling by first grade, had a lower subsequent BMIz trajectory and a significantly lower BMIz at first grade (0.27 vs 0.51, P value = 0.04 and 0.26 vs 0.51, P value = 0.03, respectively). Children who did not experience the birth of a sibling by the time they were in first grade had 2.94 greater odds of obesity (P value = 0.046) at first grade compared with children who experienced the birth of a sibling when they were between 36 to 54 months old. A birth of a sibling when the child is 24 to 54 months old is associated with a healthier BMIz trajectory. Identifying the underlying mechanism of association can help inform intervention programs. Copyright © 2016 by the American Academy of Pediatrics.

  10. Exploring the complexity of quantum control optimization trajectories.

    Science.gov (United States)

    Nanduri, Arun; Shir, Ofer M; Donovan, Ashley; Ho, Tak-San; Rabitz, Herschel

    2015-01-07

    The control of quantum system dynamics is generally performed by seeking a suitable applied field. The physical objective as a functional of the field forms the quantum control landscape, whose topology, under certain conditions, has been shown to contain no critical point suboptimal traps, thereby enabling effective searches for fields that give the global maximum of the objective. This paper addresses the structure of the landscape as a complement to topological critical point features. Recent work showed that landscape structure is highly favorable for optimization of state-to-state transition probabilities, in that gradient-based control trajectories to the global maximum value are nearly straight paths. The landscape structure is codified in the metric R ≥ 1.0, defined as the ratio of the length of the control trajectory to the Euclidean distance between the initial and optimal controls. A value of R = 1 would indicate an exactly straight trajectory to the optimal observable value. This paper extends the state-to-state transition probability results to the quantum ensemble and unitary transformation control landscapes. Again, nearly straight trajectories predominate, and we demonstrate that R can take values approaching 1.0 with high precision. However, the interplay of optimization trajectories with critical saddle submanifolds is found to influence landscape structure. A fundamental relationship necessary for perfectly straight gradient-based control trajectories is derived, wherein the gradient on the quantum control landscape must be an eigenfunction of the Hessian. This relation is an indicator of landscape structure and may provide a means to identify physical conditions when control trajectories can achieve perfect linearity. The collective favorable landscape topology and structure provide a foundation to understand why optimal quantum control can be readily achieved.

  11. 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

  12. Automated trajectory planning for multiple-flyby interplanetary missions

    Science.gov (United States)

    Englander, Jacob

    Many space mission planning problems may be formulated as hybrid optimal control problems (HOCP), i.e. problems that include both real-valued variables and categorical variables. In interplanetary trajectory design problems the categorical variables will typically specify the sequence of planets at which to perform flybys, and the real-valued variables will represent the launch date, ight times between planets, magnitudes and directions of thrust, flyby altitudes, etc. The contribution of this work is a framework for the autonomous optimization of multiple-flyby interplanetary trajectories. The trajectory design problem is converted into a HOCP with two nested loops: an "outer-loop" that finds the sequence of flybys and an "inner-loop" that optimizes the trajectory for each candidate yby sequence. The problem of choosing a sequence of flybys is posed as an integer programming problem and solved using a genetic algorithm (GA). This is an especially difficult problem to solve because GAs normally operate on a fixed-length set of decision variables. Since in interplanetary trajectory design the number of flyby maneuvers is not known a priori, it was necessary to devise a method of parameterizing the problem such that the GA can evolve a variable-length sequence of flybys. A novel "null gene" transcription was developed to meet this need. Then, for each candidate sequence of flybys, a trajectory must be found that visits each of the flyby targets and arrives at the final destination while optimizing some cost metric, such as minimizing ▵v or maximizing the final mass of the spacecraft. Three different classes of trajectory are described in this work, each of which requireda different physical model and optimization method. The choice of a trajectory model and optimization method is especially challenging because of the nature of the hybrid optimal control problem. Because the trajectory optimization problem is generated in real time by the outer-loop, the inner

  13. Comparison of Trajectories Generated by the NOAA Oil Spill Model to Trajectories Produced Using HF Radar-Derived Curents in Monterey Bay

    National Research Council Canada - National Science Library

    Smith, Margaret

    1997-01-01

    .... Trajectories produced by the NOAA/HAZMAT On-Scene Spill Model, using different combinations of surface currents and winds, were compared to trajectories generated using HF radar-derived surface currents...

  14. Trajectories of psychological distress after prison release: implications for mental health service need in ex-prisoners.

    Science.gov (United States)

    Thomas, E G; Spittal, M J; Heffernan, E B; Taxman, F S; Alati, R; Kinner, S A

    2016-02-01

    Understanding individual-level changes in mental health status after prison release is crucial to providing targeted and effective mental health care to ex-prisoners. We aimed to describe trajectories of psychological distress following prison discharge and compare these trajectories with mental health service use in the community. The Kessler Psychological Distress Scale (K10) was administered to 1216 sentenced adult prisoners in Queensland, Australia, before prison release and approximately 1, 3 and 6 months after release. We used group-based trajectory modeling to identify K10 trajectories after release. Contact with community mental health services in the year following release was assessed via data linkage. We identified five trajectory groups, representing consistently low (51.1% of the cohort), consistently moderate (29.8%), high increasing (11.6%), high declining (5.5%) and consistently very high (1.9%) psychological distress. Mood disorder, anxiety disorder, history of self-harm and risky drug use were risk factors for the high increasing, very high and high declining trajectory groups. Women were over-represented in the high increasing and high declining groups, but men were at higher risk of very high psychological distress. Within the high increasing and very high groups, 25% of participants accessed community mental health services in the first year post-release, for a median of 4.4 contact hours. For the majority of prisoners with high to very high psychological distress, distress persists after release. However, contact with mental health services in the community appears low. Further research is required to understand barriers to mental health service access among ex-prisoners.

  15. Comorbidity amplifies the effects of post-9/11 posttraumatic stress disorder trajectories on health-related quality of life.

    Science.gov (United States)

    Li, Jiehui; Zweig, Kimberly Caramanica; Brackbill, Robert M; Farfel, Mark R; Cone, James E

    2018-03-01

    The present study aims to examine the impact of physical and mental health comorbidities on the association between post-9/11 posttraumatic stress disorder (PTSD) trajectories over 10 years and health-related quality of life (HRQOL) among 9/11-exposed persons. 30,002 responding adult World Trade Center Health Registry enrollees reporting no pre-9/11 PTSD were studied. PTSD trajectories (chronic, delayed, remitted, no PTSD) were defined based on a 17-item PTSD Checklist-Specific to 9/11 across three waves of survey data. Three indicators of poor HRQOL were defined based on CDC HRQOL-4 measures. We computed age-adjusted prevalence of physical and mental health comorbidity (depression/anxiety) by PTSD trajectory and used modified Poisson regression to assess the effect of PTSD trajectory on poor HRQOL prevalence, accounting for comorbidity. Age-adjusted prevalence of overall comorbid conditions was 95.8 and 61.4% among the chronic and no-PTSD groups, respectively. Associations between 9/11-related PTSD trajectories and poor HRQOL were significant and became greater when comorbidity was included. Adjusted prevalence ratios were elevated for fair/poor health status (APR 7.3, 95% CI 6.5, 8.2), ≥ 14 unhealthy days (4.7; 95% CI 4.4, 5.1), and ≥ 14 activity limitation days during the last 30 days (9.6; 95% CI 8.1, 11.4) in the chronic PTSD group with physical and mental health comorbidity compared to those without PTSD and comorbidity; similar associations were observed for delayed PTSD. Ten years post-9/11 physical and mental health comorbidities have a substantial impact on the PTSD trajectories and HRQOL association. The need for early identification and treatment of PTSD and comorbidity should be emphasized to potentially improve HRQOL.

  16. NAVIGATION AIDS AS TOOLS TO SUPPORT THE DEVELOPMENT OF COMPETENCES IN THE CONDITIONS OF REALIZATION OF INDIVIDUAL EDUCATIONAL TRAJECTORY

    Directory of Open Access Journals (Sweden)

    E. F. Zeer

    2017-01-01

    Full Text Available Introduction. Continuing education or «education through all life» is required of the person by modern realities of the information, quickly changing society; thus, continuing education is carried out on a development trajectory, individual for each person. Maintenance of such educational process needs effective tools. The relevance of its development caused the research presented in the publication.The aim is to show the possibilities of navigation aids during realization of individual routes of the training conforming to federal state educational standards and considering the purposes and interests of each separately taken personality.Methodology and research methods. The leading methodological basis is personality-oriented approach in the implementation of individual educational trajectory. Logical-pedagogical analysis of students’ individual educational trajectory progress is used.Results and scientific novelty. The interrelation of the concepts «individual educational trajectory» and «individual educational route» is revealed. The conceptual model of maintenance of an individual educational trajectory as a set of reference points of mastering of competences necessary for the expert is offered. Navigators of educational process and cases of individual educational achievements assessment act as didactic means in model. It is shown whence application of components of models allows to: organize the professional orientation actions more effectively; exercise entrance control of knowledge prior to training; control actions during vocational training; correlate an individual trajectory of training to the standard; have a guide when studying disciplines of various cycles, when passing educational and production training, protection of final qualification work; finally, it is possible for a pupil to carry out self-estimation of the acquired competences.Practical significance. The materials of the present publication will be useful to

  17. Using machine learning and surface reconstruction to accurately differentiate different trajectories of mood and energy dysregulation in youth.

    Science.gov (United States)

    Versace, Amelia; Sharma, Vinod; Bertocci, Michele A; Bebko, Genna; Iyengar, Satish; Dwojak, Amanda; Bonar, Lisa; Perlman, Susan B; Schirda, Claudiu; Travis, Michael; Gill, Mary Kay; Diwadkar, Vaibhav A; Sunshine, Jeffrey L; Holland, Scott K; Kowatch, Robert A; Birmaher, Boris; Axelson, David; Frazier, Thomas W; Arnold, L Eugene; Fristad, Mary A; Youngstrom, Eric A; Horwitz, Sarah M; Findling, Robert L; Phillips, Mary L

    2017-01-01

    Difficulty regulating positive mood and energy is a feature that cuts across different pediatric psychiatric disorders. Yet, little is known regarding the neural mechanisms underlying different developmental trajectories of positive mood and energy regulation in youth. Recent studies indicate that machine learning techniques can help elucidate the role of neuroimaging measures in classifying individual subjects by specific symptom trajectory. Cortical thickness measures were extracted in sixty-eight anatomical regions covering the entire brain in 115 participants from the Longitudinal Assessment of Manic Symptoms (LAMS) study and 31 healthy comparison youth (12.5 y/o;-Male/Female = 15/16;-IQ = 104;-Right/Left handedness = 24/5). Using a combination of trajectories analyses, surface reconstruction, and machine learning techniques, the present study aims to identify the extent to which measures of cortical thickness can accurately distinguish youth with higher (n = 18) from those with lower (n = 34) trajectories of manic-like behaviors in a large sample of LAMS youth (n = 115; 13.6 y/o; M/F = 68/47, IQ = 100.1, R/L = 108/7). Machine learning analyses revealed that widespread cortical thickening in portions of the left dorsolateral prefrontal cortex, right inferior and middle temporal gyrus, bilateral precuneus, and bilateral paracentral gyri and cortical thinning in portions of the right dorsolateral prefrontal cortex, left ventrolateral prefrontal cortex, and right parahippocampal gyrus accurately differentiate (Area Under Curve = 0.89;p = 0.03) youth with different (higher vs lower) trajectories of positive mood and energy dysregulation over a period up to 5years, as measured by the Parent General Behavior Inventory-10 Item Mania Scale. Our findings suggest that specific patterns of cortical thickness may reflect transdiagnostic neural mechanisms associated with different temporal trajectories of positive mood and energy dysregulation in youth. This approach has

  18. Development of three-dimensional trajectory model for detecting source region of the radioactive materials released into the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kyung Suk; Park, Ki Hyun; Min, Byung Il; Kim, Sora; Yang, Byung Mo [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-05-15

    It is necessary to consider the overall countermeasure for analysis of nuclear activities according to the increase of the nuclear facilities like nuclear power and reprocessing plants in the neighboring countries including China, Taiwan, North Korea, Japan and South Korea. South Korea and comprehensive nuclear-test-ban treaty organization (CTBTO) are now operating the monitoring instruments to detect radionuclides released into the air. It is important to estimate the origin of radionuclides measured using the detection technology as well as the monitoring analysis in aspects of investigation and security of the nuclear activities in neighboring countries. A three-dimensional forward/backward trajectory model has been developed to estimate the origin of radionuclides for a covert nuclear activity. The developed trajectory model was composed of forward and backward modules to track the particle positions using finite difference method. A three-dimensional trajectory model was validated using the measured data at Chernobyl accident. The calculated results showed a good agreement by using the high concentration measurements and the locations where was near a release point. The three-dimensional trajectory model had some uncertainty according to the release time, release height and time interval of the trajectory at each release points. An atmospheric dispersion model called long-range accident dose assessment system (LADAS), based on the fields of regards (FOR) technique, was applied to reduce the uncertainties of the trajectory model and to improve the detective technology for estimating the radioisotopes emission area. The detective technology developed in this study can evaluate in release area and origin for covert nuclear activities based on measured radioisotopes at monitoring stations, and it might play critical tool to improve the ability of the nuclear safety field.

  19. Using machine learning and surface reconstruction to accurately differentiate different trajectories of mood and energy dysregulation in youth.

    Directory of Open Access Journals (Sweden)

    Amelia Versace

    Full Text Available Difficulty regulating positive mood and energy is a feature that cuts across different pediatric psychiatric disorders. Yet, little is known regarding the neural mechanisms underlying different developmental trajectories of positive mood and energy regulation in youth. Recent studies indicate that machine learning techniques can help elucidate the role of neuroimaging measures in classifying individual subjects by specific symptom trajectory. Cortical thickness measures were extracted in sixty-eight anatomical regions covering the entire brain in 115 participants from the Longitudinal Assessment of Manic Symptoms (LAMS study and 31 healthy comparison youth (12.5 y/o;-Male/Female = 15/16;-IQ = 104;-Right/Left handedness = 24/5. Using a combination of trajectories analyses, surface reconstruction, and machine learning techniques, the present study aims to identify the extent to which measures of cortical thickness can accurately distinguish youth with higher (n = 18 from those with lower (n = 34 trajectories of manic-like behaviors in a large sample of LAMS youth (n = 115; 13.6 y/o; M/F = 68/47, IQ = 100.1, R/L = 108/7. Machine learning analyses revealed that widespread cortical thickening in portions of the left dorsolateral prefrontal cortex, right inferior and middle temporal gyrus, bilateral precuneus, and bilateral paracentral gyri and cortical thinning in portions of the right dorsolateral prefrontal cortex, left ventrolateral prefrontal cortex, and right parahippocampal gyrus accurately differentiate (Area Under Curve = 0.89;p = 0.03 youth with different (higher vs lower trajectories of positive mood and energy dysregulation over a period up to 5years, as measured by the Parent General Behavior Inventory-10 Item Mania Scale. Our findings suggest that specific patterns of cortical thickness may reflect transdiagnostic neural mechanisms associated with different temporal trajectories of positive mood and energy dysregulation in youth. This

  20. Sequence-to-Sequence Prediction of Vehicle Trajectory via LSTM Encoder-Decoder Architecture

    OpenAIRE

    Park, Seong Hyeon; Kim, ByeongDo; Kang, Chang Mook; Chung, Chung Choo; Choi, Jun Won

    2018-01-01

    In this paper, we propose a deep learning based vehicle trajectory prediction technique which can generate the future trajectory sequence of surrounding vehicles in real time. We employ the encoder-decoder architecture which analyzes the pattern underlying in the past trajectory using the long short-term memory (LSTM) based encoder and generates the future trajectory sequence using the LSTM based decoder. This structure produces the $K$ most likely trajectory candidates over occupancy grid ma...