WorldWideScience

Sample records for dynamics correction terms

  1. Moduli Corrections to D-term Inflation

    CERN Document Server

    Brax, P; Davis, S C; De van Bruck, C; Jeannerot, R; Postma, M; Brax, Ph.; Davis, Stephen C.

    2007-01-01

    We present a D-term hybrid inflation model, embedded in supergravity with moduli stabilisation. Its novel features allow us to overcome the serious challenges of combining D-term inflation and moduli fields within the same string-motivated theory. One salient point of the model is the positive definite uplifting D-term arising from the moduli stabilisation sector. By coupling this D-term to the inflationary sector, we generate an effective Fayet-Iliopoulos term. Moduli corrections to the inflationary dynamics are also obtained. Successful inflation is achieved for a range of parameter values with spectral index compatible with the WMAP3 data. Cosmic D-term strings are also formed at the end of inflation; these are no longer BPS objects. The properties of the strings are studied.

  2. Dynamic term structure models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Meldrum, Andrew

    This paper studies whether dynamic term structure models for US nominal bond yields should enforce the zero lower bound by a quadratic policy rate or a shadow rate specification. We address the question by estimating quadratic term structure models (QTSMs) and shadow rate models with at most four...

  3. Transition-state theory and dynamical corrections

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing

    2002-01-01

    . The correction factor due to non-adiabatic dynamics is considered in relation to the non-activated dissociative sticking of N-2 on Fe(111). For this process, conventional transition-state theory gives a sticking probability which is about 10 times too large (at T = 300 K). We estimate that the sticking......We consider conventional transition-state theory, and show how quantum dynamical correction factors can be incorporated in a simple fashion, as a natural extension of the fundamental formulation. Corrections due to tunneling and non-adiabatic dynamics are discussed, with emphasis on the latter...

  4. Relativistic corrections to molecular dynamic dipole polarizabilities

    DEFF Research Database (Denmark)

    Kirpekar, Sheela; Oddershede, Jens; Jensen, Hans Jørgen Aagaard

    1995-01-01

    Using response function methods we report calculations of the dynamic isotropic polarizability of SnH4 and PbH4 and of the relativistic corrections to it in the random phase approximation and at the correlated multiconfigurational linear response level of approximation. All relativistic corrections...

  5. The main beam correction term in kinetic energy release from metastable peaks.

    Science.gov (United States)

    Petersen, Allan Christian

    2017-08-26

    The correction term for the precursor ion signal width in determination of kinetic energy release is reviewed and the correction term is formally derived. The derived correction term differs from the traditionally applied term. An experimental finding substantiates the inaccuracy in the latter. The application of the 'T-value' to study kinetic energy release is found preferable to kinetic energy release distributions when the metastable peaks are slim and simple Gaussians. For electronically predissociated systems a 'borderline zero' kinetic energy release can be directly interpreted in terms of reaction dynamics with strong curvature in the reaction coordinate. This article is protected by copyright. All rights reserved.

  6. A novel method of dynamic correction in the time domain

    Science.gov (United States)

    Hessling, J. P.

    2008-07-01

    The dynamic error of measured signals is sometimes unacceptably large. If the dynamic properties of the measurement system are known, the true physical signal may to some extent be re-constructed. With a parametrized characterization of the system and sampled signals, time-domain digital filters may be utilized for correction. In the present work a general method for synthesizing such correction filters is developed. It maps the dynamic parameters of the measurement system directly on to the filter coefficients and utilizes time reversed filtering. This avoids commonly used numerical optimization in the filter synthesis. The method of correction is simple with absolute repeatability and stability, and results in a low residual error. Explicit criteria to control both the horizontal (time) and vertical (amplitude) discretization errors are presented in terms of the utilization of bandwidth and noise gain, respectively. To evaluate how close to optimal the correction is, these errors are also formulated in relation to the signal-to-noise ratio of the original measurement system. For purposes of illustration, typical mechanical and piezo-electric transducer systems for measuring force, pressure or acceleration are simulated and dynamically corrected with such dedicated digital filters.

  7. Correction terms for the thermodynamics of a black Saturn

    Energy Technology Data Exchange (ETDEWEB)

    Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Pourhassan, Behnam, E-mail: b.pourhassan@du.ac.ir [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of)

    2015-12-17

    In this paper, we will analyze the effects of thermal fluctuations on the stability of a black Saturn. The entropy of the black Saturn will get corrected due to these thermal fluctuations. We will demonstrate that the correction term generated by these thermal fluctuations is a logarithmic term. Then we will use this corrected value of the entropy to obtain bounds for various parameters of the black Saturn. We will also analyze the thermodynamical stability of the black Saturn in presence of thermal fluctuations, using this corrected value of the entropy.

  8. Direct anharmonic correction method by molecular dynamics

    Science.gov (United States)

    Liu, Zhong-Li; Li, Rui; Zhang, Xiu-Lu; Qu, Nuo; Cai, Ling-Cang

    2017-04-01

    The quick calculation of accurate anharmonic effects of lattice vibrations is crucial to the calculations of thermodynamic properties, the construction of the multi-phase diagram and equation of states of materials, and the theoretical designs of new materials. In this paper, we proposed a direct free energy interpolation (DFEI) method based on the temperature dependent phonon density of states (TD-PDOS) reduced from molecular dynamics simulations. Using the DFEI method, after anharmonic free energy corrections we reproduced the thermal expansion coefficients, the specific heat, the thermal pressure, the isothermal bulk modulus, and the Hugoniot P- V- T relationships of Cu easily and accurately. The extensive tests on other materials including metal, alloy, semiconductor and insulator also manifest that the DFEI method can easily uncover the rest anharmonicity that the quasi-harmonic approximation (QHA) omits. It is thus evidenced that the DFEI method is indeed a very efficient method used to conduct anharmonic effect corrections beyond QHA. More importantly it is much more straightforward and easier compared to previous anharmonic methods.

  9. Dynamic Correction Algorithm of Rolling Force in Plate Rolling

    Institute of Scientific and Technical Information of China (English)

    QIU Hong-lei; WANG Jun; HU Xian-lei; WANG Zhao-dong; WANG Guo-dong

    2005-01-01

    Based on the Shougang plat mill project, an on-line dynamic correction algorithm was analyzed. This algorithm can adjust model coefficients better because the reasonable correction is based on the measured and calculated rolling force. The results of application on site show that this on-line dynamic correction algorithm is effective.

  10. Assessing atmospheric bias correction for dynamical consistency using potential vorticity

    Science.gov (United States)

    Rocheta, Eytan; Evans, Jason P.; Sharma, Ashish

    2014-12-01

    Correcting biases in atmospheric variables prior to impact studies or dynamical downscaling can lead to new biases as dynamical consistency between the ‘corrected’ fields is not maintained. Use of these bias corrected fields for subsequent impact studies and dynamical downscaling provides input conditions that do not appropriately represent intervariable relationships in atmospheric fields. Here we investigate the consequences of the lack of dynamical consistency in bias correction using a measure of model consistency—the potential vorticity (PV). This paper presents an assessment of the biases present in PV using two alternative correction techniques—an approach where bias correction is performed individually on each atmospheric variable, thereby ignoring the physical relationships that exists between the multiple variables that are corrected, and a second approach where bias correction is performed directly on the PV field, thereby keeping the system dynamically coherent throughout the correction process. In this paper we show that bias correcting variables independently results in increased errors above the tropopause in the mean and standard deviation of the PV field, which are improved when using the alternative proposed. Furthermore, patterns of spatial variability are improved over nearly all vertical levels when applying the alternative approach. Results point to a need for a dynamically consistent atmospheric bias correction technique which results in fields that can be used as dynamically consistent lateral boundaries in follow-up downscaling applications.

  11. Proton Radius, Darwin-Foldy Term and Radiative Corrections

    CERN Document Server

    Jentschura, U D

    2010-01-01

    We discuss the role of the so-called Darwin-Foldy term in the evaluation of the proton and deuteron charge radii from atomic hydrogen spectroscopy and nuclear scattering data. The question of whether this term should be included or excluded from the nuclear radius has been controversially discussed in the literature. We attempt to clarify which literature values correspond to which conventions. A detailed discussion of the conventions appears useful because a recent experiment [R. Pohl et al., Nature vol. 466, p. 213 (2010)] has indicated that there is a discrepancy between the proton charge radii inferred from ordinary ("electronic") atomic hydrogen and muonic hydrogen. We also investigate the role of quantum electrodynamic radiative corrections in the determination of nuclear radii from scattering data, and propose a definition of the nuclear self energy which is compatible with the subtraction of the radiative corrections in scattering experiments.

  12. Global Intensity Correction in Dynamic Scenes

    NARCIS (Netherlands)

    Withagen, P.J.; Schutte, K.; Groen, F.C.A.

    2010-01-01

    Changing image intensities causes problems for many computer vision applications operating in unconstrained environments. We propose generally applicable algorithms to correct for global differences in intensity between images recorded with a static or slowly moving camera, regardless of the cause o

  13. Dynamical Casimir effect and loop corrections

    Science.gov (United States)

    Akhmedov, E. T.; Alexeev, S. O.

    2017-09-01

    We calculate quantum loop corrections to the stress-energy flux caused by moving mirrors. We consider massless, self-interacting, ϕ4, real scalar theory. In these calculations we encounter new and quite unexpected subtleties due to the absence of global hyperbolicity in the presence of mirrors. We attempt to clearly phrase as many hidden assumptions and complications as possible that appear while solving the problem in question. On top of that, we find that quantum loop corrections to the stress-energy flux grow with time and are not suppressed in comparison with the semiclassical contributions. Thus, we observe the breakdown of the perturbation theory, and we discuss its physical origin and ways to deal with such a situation. As a byproduct, we observe a similarity of the problem in question with that for the minimally coupled, massless scalar field in de Sitter space.

  14. Maintenance performance improvement with System Dynamics: A Corrective Maintenance showcase

    NARCIS (Netherlands)

    Deenen, R.E.M.; Van Daalen, C.E.; Koene, E.G.C.

    2008-01-01

    This paper presents a case study of an analysis of a Corrective Maintenance process to realize performance improvement. The Corrective Maintenance process is supported by SAP, which has indicated the performance realisation problem. System Dynamics is used in a Group Model Building process to

  15. GPS dynamic cycle slip detection and correction with baseline constraint

    Institute of Scientific and Technical Information of China (English)

    Liu Zhenkun; Huang Ahunji

    2009-01-01

    When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable to the dynamic measurement using GPS carrier phase: the cycle slips detection is first achieved by triple difference observables, then the cycle slips correction is performed with baseline length constraint. The simulation results show that the proposed method is effective to the dynamic cycle slips problem.

  16. Multi-view video color correction using dynamic programming

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Color inconsistency between views is an important problem to be solved in multi-view video systems. A multi-view video color correction method using dynamic programming is proposed. Three-dimensional histograms are constructed with sequential conditional probability in HSI color space. Then, dynamic programming is used to seek the best color mapping relation with the minimum cost path between target image histogram and source image histogram. Finally, video tracking technique is performed to correct multi-view video. Experimental results show that the proposed method can obtain better subjective and objective performance in color correction.

  17. Software for Correcting the Dynamic Error of Force Transducers

    Directory of Open Access Journals (Sweden)

    Naoki Miyashita

    2014-07-01

    Full Text Available Software which corrects the dynamic error of force transducers in impact force measurements using their own output signal has been developed. The software corrects the output waveform of the transducers using the output waveform itself, estimates its uncertainty and displays the results. In the experiment, the dynamic error of three transducers of the same model are evaluated using the Levitation Mass Method (LMM, in which the impact forces applied to the transducers are accurately determined as the inertial force of the moving part of the aerostatic linear bearing. The parameters for correcting the dynamic error are determined from the results of one set of impact measurements of one transducer. Then, the validity of the obtained parameters is evaluated using the results of the other sets of measurements of all the three transducers. The uncertainties in the uncorrected force and those in the corrected force are also estimated. If manufacturers determine the correction parameters for each model using the proposed method, and provide the software with the parameters corresponding to each model, then users can obtain the waveform corrected against dynamic error and its uncertainty. The present status and the future prospects of the developed software are discussed in this paper.

  18. DYNAMIC CORRECTION OF ROUGHNESS IN THE HYDRODYNAMIC MODEL

    Institute of Scientific and Technical Information of China (English)

    BAO Wei-min; ZHANG Xiao-qin; QU Si-min

    2009-01-01

    Based on the hydrodynamic model and the Xinanjiang model, the river stage forecasting model has been proposed. But its performance is not satisfactory as applied to estuary areas. River roughness is a sensitive parameter in the hydrodynamic model, and its value is related to some substantial uncertainties in the tidal river. According to roughness tests, a new method of roughness dynamic correction was developed to improve the performance of the stage model. The method was focused on the usage of observed data for the studied section, and its parameters were analyzed. Nested with the dynamic correction of roughness, the stage model was applied to the tidal reach of the Caoe River. The results demonstrate that the roughness dynamic correction can improve the simulation accuracy of the stage model, and especially has the capacity of reducing the errors at peak stages.

  19. Predictor-based error correction method in short-term climate prediction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In terms of the basic idea of combining dynamical and statistical methods in short-term climate prediction, a new prediction method of predictor-based error correction (PREC) is put forward in order to effectively use statistical experiences in dynamical prediction. Analyses show that the PREC can reasonably utilize the significant correlations between predictors and model prediction errors and correct prediction errors by establishing statistical prediction model. Besides, the PREC is further applied to the cross-validation experiments of dynamical seasonal prediction on the operational atmosphere-ocean coupled general circulation model of China Meteorological Administration/National Climate Center by selecting the sea surface temperature index in Ni(n)o3 region as the physical predictor that represents the prevailing ENSO-cycle mode of interannual variability in climate system. It is shown from the prediction results of summer mean circulation and total precipitation that the PREC can improve predictive skills to some extent. Thus the PREC provides a new approach for improving short-term climate prediction.

  20. An Equilibrium-Correction Model for Dynamic Network Data

    NARCIS (Netherlands)

    D.J. Dekker (David); Ph.H.B.F. Franses (Philip Hans); D. Krackhardt (David)

    2001-01-01

    textabstractWe propose a two-stage MRQAP to analyze dynamic network data, within the framework of an equilibrium-correction (EC) model. Extensive simulation results indicate practical relevance of our method and its improvement over standard OLS. An empirical illustration additionally shows that the

  1. An equilibrium-correction model for dynamic network data

    NARCIS (Netherlands)

    R. Dekker (Rommert); Ph.H.B.F. Franses (Philip Hans); D. Krackhardt (David)

    2003-01-01

    textabstractWe propose a two-stage MRQAP to analyze dynamic network data, within the framework of an equilibrium-correction (EC) model. Extensive simulation results indicate practical relevance of our method and its improvement over standard OLS. An empirical illustration additionally shows that the

  2. Localised distributions and criteria for correctness in complex Langevin dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Aarts, Gert, E-mail: g.aarts@swan.ac.uk [Department of Physics, College of Science, Swansea University, Swansea (United Kingdom); Giudice, Pietro, E-mail: p.giudice@uni-muenster.de [Department of Physics, College of Science, Swansea University, Swansea (United Kingdom); Seiler, Erhard, E-mail: ehs@mppmu.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München (Germany)

    2013-10-15

    Complex Langevin dynamics can solve the sign problem appearing in numerical simulations of theories with a complex action. In order to justify the procedure, it is important to understand the properties of the real and positive distribution, which is effectively sampled during the stochastic process. In the context of a simple model, we study this distribution by solving the Fokker–Planck equation as well as by brute force and relate the results to the recently derived criteria for correctness. We demonstrate analytically that it is possible that the distribution has support in a strip in the complexified configuration space only, in which case correct results are expected. -- Highlights: •Characterisation of the equilibrium distribution sampled in complex Langevin dynamics. •Connection between criteria for correctness and breakdown. •Solution of the Fokker–Planck equation in the case of real noise. •Analytical determination of support in complexified space.

  3. A Correction Method Suitable for Dynamical Seasonal Prediction

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; LIN Zhaohui

    2006-01-01

    Based on the hindcast results of summer rainfall anomalies over China for the period 1981-2000 by the Dynamical Climate Prediction System (IAP-DCP) developed by the Institute of Atmospheric Physics,a correction method that can account for the dependence of model's systematic biases on SST anomalies is proposed. It is shown that this correction method can improve the hindcast skill of the IAP-DCP for summer rainfall anomalies over China, especially in western China and southeast China, which may imply its potential application to real-time seasonal prediction.

  4. Long-term dynamics simulation: Modeling requirements

    Energy Technology Data Exchange (ETDEWEB)

    Morched, A.S.; Kar, P.K.; Rogers, G.J.; Morison, G.K. (Ontario Hydro, Toronto, ON (Canada))

    1989-12-01

    This report details the required performance and modelling capabilities of a computer program intended for the study of the long term dynamics of power systems. Following a general introduction which outlines the need for long term dynamic studies, the modelling requirements for the conduct of such studies is discussed in detail. Particular emphasis is placed on models for system elements not normally modelled in power system stability programs, which will have a significant impact in the long term time frame of minutes to hours following the initiating disturbance. The report concludes with a discussion of the special computational and programming requirements for a long term stability program. 43 refs., 36 figs.

  5. Beam dynamics in rf guns and emittance correction techniques

    Science.gov (United States)

    Serafini, Luca

    1994-02-01

    In this paper we present a general review of beam dynamics in a laser-driven rf gun. The peculiarity of such an accelerating structure versus other conventional multi-cell linac structures is underlined on the basis of the Panofsky-Wenzel theorem, which is found to give a theoretical background for the well known Kim's model. A basic explanation for some proposed methods to correct rf induced emittance growth is also derived from the theorem. We also present three emittance correction techniques for the recovery of space-charge induced emittance growth, namely the optimum distributed disk-like bunch technique, the use of rf spatial harmonics to correct spherical aberration induced by space charge forces and the technique of emittance filtering by clipping the electron beam. The expected performances regarding the beam quality achievable with different techniques, as predicted by scaling laws and simulations, are analyzed, and, where available, compared to experimental results.

  6. Statistical Correction for Short-term Wind Forecasting

    Science.gov (United States)

    Jiang, J.; Tambke, J.; Heinemann, D.

    2009-04-01

    The uncertainty of wind speed forecasts from Numerical Weather Predictions (NWP) is a main source of errors in wind power forecasts. Despite increased accuracy of wind power forecasts in the last years, large wind power forecast errors still occur due to local weather and/or synoptic systems that either develop locally or that are phase-shifted relative to the forecast. The main error sources of NWP are, amongst others, inaccurate initial and/or lateral boundary conditions and inadequate representation of local forcing. Wind measurements in the WMEP program and the wind field forecasts of DWD-LM(German Weather Service - Local Model) in 2004 and from Sept. to Dec. of 2006 are used for correcting DWD-LM wind forecasts. In order to remove systematic error, phase error, or local-scale error in wind forecasts, three kinds of methods, bias correction, phase correction and Cressman technique are applied. Using bias increments changing with wind direction, the wind forecasts are modified. After bias correction, RMSE ( Root Mean Square Error ) of corrected forecasts decrease 0.1m/s to 0.4m/s. Diurnal or seasonal change of bias is also important. In addition, with optimum phase-shift vectors, the phase-shift correction is applied. It reduces the RMSE about 0.1m/s to 0.5m/s at different time steps. Moreover, statistical Cressman correction increments were obtained by Cressman technique and used to correct wind forecasts. After Cressman correction, the RMSE of wind forecasts decreases 0.1m/s to 0.2m/s. The results show that bias correction, phase correction and Cressman scheme do, to some extent, improve wind speed forecasts. That contributes to the improvement of wind power forecasts. As part of the new EU-project "SafeWind", we are continuing that study with NWP-data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and wind speed observations over Europe.

  7. Correction terms to Newton law due to induced gravity in AdS background

    CERN Document Server

    Ito, M

    2003-01-01

    We calculate small correction terms to gravitational potential on Randall-Sundrum brane with an induced Einstein term. The behaviors of the correction terms depend on the magnitudes of $AdS$ radius $k^{-1}$ and a characteristic length scale $\\l$ of model. We present the gravitational potential for arbitrary $k$ and $\\l$ at all distances.

  8. Observation-based correction of dynamical models using thermostats

    Science.gov (United States)

    Frank, Jason; Leimkuhler, Benedict

    2017-01-01

    Models used in simulation may give accurate short-term trajectories but distort long-term (statistical) properties. In this work, we augment a given approximate model with a control law (a ‘thermostat’) that gently perturbs the dynamical system to target a thermodynamic state consistent with a set of prescribed (possibly evolving) observations. As proof of concept, we provide an example involving a point vortex fluid model on the sphere, for which we show convergence of equilibrium quantities (in the stationary case) and the ability of the thermostat to dynamically track a transient state. PMID:28265197

  9. A Phillips curve interpretation of error-correction models of the wage and price dynamics

    DEFF Research Database (Denmark)

    Harck, Søren H.

    -correction setting, which actually seems to capture the wage and price dynamics of many large- scale econometric models quite well, is fully compatible with the notion of an old-fashioned Phillips curve with finite slope. It is shown how the steady-state impact of various shocks to the model can be profitably...... conceived of and interpreted in terms of (and to some extent even calculated by means of) this long-run Phillips curve.    ...

  10. Failure of random matrix theory to correctly describe quantum dynamics.

    Science.gov (United States)

    Kottos, T; Cohen, D

    2001-12-01

    Consider a classically chaotic system that is described by a Hamiltonian H(0). At t=0 the Hamiltonian undergoes a sudden change (H)0-->H. We consider the quantum-mechanical spreading of the evolving energy distribution, and argue that it cannot be analyzed using a conventional random-matrix theory (RMT) approach. Conventional RMT can be trusted only to the extent that it gives trivial results that are implied by first-order perturbation theory. Nonperturbative effects are sensitive to the underlying classical dynamics, and therefore the Planck's over 2 pi-->0 behavior for effective RMT models is strikingly different from the correct semiclassical limit.

  11. Dynamical D-terms in supergravity

    Directory of Open Access Journals (Sweden)

    Valerie Domcke

    2015-02-01

    Full Text Available Most phenomenological models of supersymmetry breaking rely on nonzero F-terms rather than nonzero D-terms. An important reason why D-terms are often neglected is that it turns out to be very challenging to realize D-terms at energies parametrically smaller than the Planck scale in supergravity. As we demonstrate in this paper, all conventional difficulties may, however, be overcome if the generation of the D-term is based on strong dynamics. To illustrate our idea, we focus on a certain class of vector-like SUSY breaking models that enjoy a minimal particle content and which may be easily embedded into more complete scenarios. We are then able to show that, upon gauging a global flavor symmetry, an appropriate choice of Yukawa couplings readily allows to dynamically generate a D-term at an almost arbitrary energy scale. This includes in particular the natural and consistent realization of D-terms around, above and below the scale of grand unification in supergravity, without the need for fine-tuning of any model parameters. Our construction might therefore bear the potential to open up a new direction for model building in supersymmetry and early universe cosmology.

  12. Correction

    DEFF Research Database (Denmark)

    Pinkevych, Mykola; Cromer, Deborah; Tolstrup, Martin

    2016-01-01

    [This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.].......[This corrects the article DOI: 10.1371/journal.ppat.1005000.][This corrects the article DOI: 10.1371/journal.ppat.1005740.][This corrects the article DOI: 10.1371/journal.ppat.1005679.]....

  13. The Dynamics of Terms in Accounting

    DEFF Research Database (Denmark)

    Fuertes-Olivera, Pedro A.; Nielsen, Sandro

    2011-01-01

    European accounting terminology is dynamic as term creation and formation occurs on national, European Union and international levels. Although English is the lingua franca of accounting, international accounting standards in English exist on a par with their translations into other languages....... However, an analysis of online dictionaries shows that these cannot cope with the dynamic nature of accounting terminology. We discuss a network of internet dictionaries in English, Danish, and Spanish that was compiled using the functional approach to specialised lexicography. We show how terminologists...... can work in subject fields where culture and context play a key role in the development of nationally accepted and internationally recommended terms, and propose ways to remedy deficiencies identified in the dictionaries examined. Finally, we discuss strategies for translating English metaphorical...

  14. Long term changes of altimeter range and geophysical corrections at altimetry calibration sites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Cheng, Yongcun; Pascal Willis

    2013-01-01

    Accurate sea level trend determination is fundamentally related to calibration of both the instrument as well as to investigate if there are linear trends in the set of standard geophysical and range corrections applied to the sea level observations. Long term changes in range corrections can leak...... trends in the sum of range corrections are found for the calibrations sites both for local scales (within 50km around the selected site) and for regional scales (within 300km). However, the geophysical corrections accounting for atmospheric pressure loading and high frequency sea level variations...

  15. The Dynamics of Terms in Accounting

    DEFF Research Database (Denmark)

    Fuertes-Olivera, Pedro A.; Nielsen, Sandro

    2011-01-01

    can work in subject fields where culture and context play a key role in the development of nationally accepted and internationally recommended terms, and propose ways to remedy deficiencies identified in the dictionaries examined. Finally, we discuss strategies for translating English metaphorical....... However, an analysis of online dictionaries shows that these cannot cope with the dynamic nature of accounting terminology. We discuss a network of internet dictionaries in English, Danish, and Spanish that was compiled using the functional approach to specialised lexicography. We show how terminologists...

  16. From M-theory higher curvature terms to α′ corrections in F-theory

    Directory of Open Access Journals (Sweden)

    Thomas W. Grimm

    2016-02-01

    Full Text Available We perform a Kaluza–Klein reduction of eleven-dimensional supergravity on a Calabi–Yau fourfold including terms quartic and cubic in the Riemann curvature and determine the induced corrections to the three-dimensional two-derivative N=2 effective action. We focus on the effective Einstein–Hilbert term and the kinetic terms for vectors. Dualizing the vectors into scalars, we derive the resulting Kähler potential and complex coordinates. The classical expressions for the Kähler coordinates are non-trivially modified by terms containing the third Chern form of the background Calabi–Yau fourfold, while the functional form of the Kähler potential is shown to be uncorrected. We omit terms proportional to the non-harmonic part of the third Chern form. For elliptically fibered Calabi–Yau fourfolds the corrections can be uplifted to a four-dimensional F-theory compactification. We argue that also the four-dimensional N=1 Kähler coordinates receive non-trivial corrections. We find a simple expression for the induced corrections for different Abelian and non-Abelian seven-brane configurations by scanning over many Calabi–Yau fourfolds with resolved singularities. The interpretation of this expression leads us to conjecture that the higher-curvature corrections correspond to α′2 corrections that arise from open strings at the self-intersection of seven-branes.

  17. From M-theory higher curvature terms to α‧ corrections in F-theory

    Science.gov (United States)

    Grimm, Thomas W.; Keitel, Jan; Savelli, Raffaele; Weissenbacher, Matthias

    2016-02-01

    We perform a Kaluza-Klein reduction of eleven-dimensional supergravity on a Calabi-Yau fourfold including terms quartic and cubic in the Riemann curvature and determine the induced corrections to the three-dimensional two-derivative N = 2 effective action. We focus on the effective Einstein-Hilbert term and the kinetic terms for vectors. Dualizing the vectors into scalars, we derive the resulting Kähler potential and complex coordinates. The classical expressions for the Kähler coordinates are non-trivially modified by terms containing the third Chern form of the background Calabi-Yau fourfold, while the functional form of the Kähler potential is shown to be uncorrected. We omit terms proportional to the non-harmonic part of the third Chern form. For elliptically fibered Calabi-Yau fourfolds the corrections can be uplifted to a four-dimensional F-theory compactification. We argue that also the four-dimensional N = 1 Kähler coordinates receive non-trivial corrections. We find a simple expression for the induced corrections for different Abelian and non-Abelian seven-brane configurations by scanning over many Calabi-Yau fourfolds with resolved singularities. The interpretation of this expression leads us to conjecture that the higher-curvature corrections correspond to α‧2 corrections that arise from open strings at the self-intersection of seven-branes.

  18. Transition State Theory: Variational Formulation, Dynamical Corrections, and Error Estimates

    Science.gov (United States)

    vanden-Eijnden, Eric

    2009-03-01

    Transition state theory (TST) is discussed from an original viewpoint: it is shown how to compute exactly the mean frequency of transition between two predefined sets which either partition phase space (as in TST) or are taken to be well separate metastable sets corresponding to long-lived conformation states (as necessary to obtain the actual transition rate constants between these states). Exact and approximate criterions for the optimal TST dividing surface with minimum recrossing rate are derived. Some issues about the definition and meaning of the free energy in the context of TST are also discussed. Finally precise error estimates for the numerical procedure to evaluate the transmission coefficient κS of the TST dividing surface are given, and it shown that the relative error on κS scales as 1/√κS when κS is small. This implies that dynamical corrections to the TST rate constant can be computed efficiently if and only if the TST dividing surface has a transmission coefficient κS which is not too small. In particular the TST dividing surface must be optimized upon (for otherwise κS is generally very small), but this may not be sufficient to make the procedure numerically efficient (because the optimal dividing surface has maximum κS, but this coefficient may still be very small).

  19. Motion correction of dynamic contrast enhanced MRI of the liver

    Science.gov (United States)

    Jansen, Mariëlle J. A.; Veldhuis, Wouter B.; van Leeuwen, Maarten S.; Pluim, Josien P. W.

    2017-02-01

    Motion correction of dynamic contrast enhanced magnetic resonance images (DCE-MRI) is a challenging task, due to changes in image appearance. In this study a groupwise registration, using a principle component analysis (PCA) based metric, is evaluated for clinical DCE MRI of the liver. The groupwise registration transforms the images to a common space, rather than to a reference volume as conventional pairwise methods do, and computes the similarity metric on all volumes simultaneously. This groupwise registration method is compared to a pairwise approach using a mutual information metric. Clinical DCE MRI of the abdomen of eight patients were included. Per patient one lesion in the liver was manually segmented in all temporal images (N=16). The registered images were compared for accuracy, spatial and temporal smoothness after transformation, and lesion volume change. Compared to a pairwise method or no registration, groupwise registration provided better alignment. In our recently started clinical study groupwise registered clinical DCE MRI of the abdomen of nine patients were scored by three radiologists. Groupwise registration increased the assessed quality of alignment. The gain in reading time for the radiologist was estimated to vary from no difference to almost a minute. A slight increase in reader confidence was also observed. Registration had no added value for images with little motion. In conclusion, the groupwise registration of DCE MR images results in better alignment than achieved by pairwise registration, which is beneficial for clinical assessment.

  20. Dynamical parton distributions from DGLAP equations with nonlinear corrections

    CERN Document Server

    Wang, Rong

    2016-01-01

    Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two different nonperturbative inputs. One is the naive three valence quarks input and the other is three valence quarks with flavor-asymmetric sea components input. Basically, both data sets are compatible with the experimental measurements at high scale ($Q^2>2$ GeV$^2$). Furthermore, our analysis shows that the input with flavor-asymmetric sea components better reproduce the structure functions at high $Q^2$. Generally, the obtained parton distribution functions, especially the gluon distribution functions, are the good options of inputs for simulations of high energy scattering processes. The analysis is performed under the fixed-flavor number scheme for $n_f=$ 3, 4, 5 and uses the $\\overline{\\text MS}$ scheme for the running coupling $\\alpha_s$ and the heavy-quark masses. Both d...

  1. From M-theory higher curvature terms to α' corrections in F-theory

    NARCIS (Netherlands)

    Grimm, Thomas W.; Keitel, Jan; Savelli, Raffaele; Weissenbacher, Matthias

    2016-01-01

    We perform a Kaluza-Klein reduction of eleven-dimensional supergravity on a Calabi-Yau fourfold including terms quartic and cubic in the Riemann curvature and determine the induced corrections to the three-dimensional N=2 effective action. We focus on the effective Einstein-Hilbert term and the

  2. A PREDICT-CORRECT NUMERICAL INTEGRATION SCHEME FOR SOLVING NONLINEAR DYNAMIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    Fan Jianping; Huang Tao; Tang Chak-yin; Wang Cheng

    2006-01-01

    A new numerical integration scheme incorporating a predict-correct algorithm for solving the nonlinear dynamic systems was proposed in this paper. A nonlinear dynamic system governed by the equaton (v) = F(v, t) was transformed into the form as (v) = Hv+ f(v, t). The nonlinear part f(v, t) was then expanded by Taylor series and only the first-order term retained in the polynomial. Utilizing the theory of linear differential equation and the precise time-integration method, an exact solution for linearizing equation was obtained. In order to find the solution of the original system, a third-order interpolation polynomial of v was used and an equivalent nonlinear ordinary differential equation was regenerated. With a predicted solution as an initial value and an iteration scheme, a corrected result was achieved. Since the error caused by linearization could be eliminated in the correction process, the accuracy of calculation was improved greatly. Three engineering scenarios were used to assess the accuracy and reliability of the proposed method and the results were satisfactory.

  3. The dynamic correction of collimation errors of CT slicing pictures

    Institute of Scientific and Technical Information of China (English)

    LIU Ya-xiong; Sekou Sing-are; LI Di-chen; LU Bing-heng

    2006-01-01

    To eliminate the motion artifacts of CT images caused by patient motions and other related errors,two kinds of correctors (A type and U type) are proposed to monitor the scanning process and correct the motion artifacts of the original images via reverse geometrical transformation such as reverse scaling,moving,rotating and offsetting.The results confirm that the correction method with any of the correctors can improve the accuracy and reliability of CT images,which facilitates in eliminating or decreasing the motion artifacts and correcting other static errors and image processing errors.This provides a foundation for the 3D reconstruction and accurate fabrication of the customized implants.

  4. Local Dynamic Reactive Power for Correction of System Voltage Problems

    Energy Technology Data Exchange (ETDEWEB)

    Kueck, John D [ORNL; Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Xu, Yan [ORNL; Li, Huijuan [University of Tennessee, Knoxville (UTK); Adhikari, Sarina [ORNL; Irminger, Philip [ORNL

    2008-12-01

    Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

  5. A dynamic compensation strategy to correct patient-positioning errors in conformal prostate radiotherapy.

    Science.gov (United States)

    Lauve, A D; Siebers, J V; Crimaldi, A J; Hagan, M P; Kealla, P J

    2006-06-01

    Traditionally, pretreatment detected patient-positioning errors have been corrected by repositioning the couch to align the patient to the treatment beam. We investigated an alternative strategy: aligning the beam to the patient by repositioning the dynamic multileaf collimator and adjusting the beam weights, termed dynamic compensation. The purpose of this study was to determine the geometric range of positioning errors for which the dynamic compensation method is valid in prostate cancer patients treated with three-dimensional conformal radiotherapy. Twenty-five previously treated prostate cancer patients were replanned using a four-field technique to deliver 72 Gy to 95% of the planning target volume (PTV). Patient-positioning errors were introduced by shifting the patient reference frame with respect to the treatment isocenter. Thirty-six randomly selected isotropic displacements with magnitudes of 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 cm were sampled for each patient, for a total of 5400 errors. Dynamic compensation was used to correct each of these errors by conforming the beam apertures to the new target position and adjusting the monitor units using inverse-square and off-axis factor corrections. The dynamic compensation plans were then compared with the original treatment plans via dose-volume histogram (DVH) analysis. Changes of more than 5% of the prescription dose, 3.6 Gy, were deemed significant. Compared with the original treatment plans, dynamic compensation produced small discrepancies in isodose distributions and DVH analyses. These differences increased with the magnitudes of the initial patient-positioning errors. Coverage of the PTV was excellent: D95 and Dmean were not increased or decreased by more than 5% of the prescription dose, and D5 was not decreased by more than 5% of the prescription dose for any of the 5400 simulated positioning errors. D5 was increased by more than 5% of the prescription dose in only three of the 5400 positioning errors

  6. Long-term dynamics of Typha populations

    Science.gov (United States)

    Grace, J.B.; Wetzel, R.G.

    1998-01-01

    The zonation of Typha populations in an experimental pond in Michigan was re-examined 15 years after the original sampling to gain insight into the long-term dynamics. Current distributions of Typha populations were also examined in additional experimental ponds at the site that have been maintained for 23 years. The zonation between T. latifolia and T. angustifolia in the previously studied pond 15 years after the initial sampling revealed that the density and distribution of shoots had not changed significantly. Thus, it appears that previously reported results (based on 7- year old populations) have remained consistent over time. Additional insight into the interaction between these two taxa was sought by comparing mixed and monoculture stands in five experimental ponds that have remained undisturbed for their 23-year history. The maximum depth of T. latifolia, the shallow- water species, was not significantly reduced when growing in the presence of the more flood tolerant T. angustifolia. In contrast, the minimum depth of T. angustifolia was reduced from 0 to 37 cm when in the presence of T. latifolia. When total populations were compared between monoculture and mixed stands, the average density of T. angustifolia shoots was 59.4 percent lower in mixed stands while the density of T. latifolia was 32 percent lower, with T. angustifolia most affected at shallow depths (reduced by 92 percent) and T. latifolia most affected at the deepest depths (reduced by 60 percent). These long-term observations indicate that competitive displacement between Typha taxa has remained stable over time.

  7. One loop graviton corrections to dynamical photons in de Sitter

    CERN Document Server

    Glavan, D; Prokopec, Tomislav; Woodard, R P

    2016-01-01

    We employ a recent, general gauge computation of the one loop graviton contribution to the vacuum polarization on de Sitter to solve for one loop corrections to the photon mode function. The vacuum polarization takes the form of a gauge independent, spin 2 contribution and a gauge dependent, spin 0 contribution. We show that the leading secular corrections derive entirely from the spin 2 contribution.

  8. Cosmic dynamics with entropy corrected holographic dark energy

    CERN Document Server

    Sadjadi, H Mohseni

    2010-01-01

    We investigate the model of holographic dark energy with logarithmic correction to its energy density. This modification is motivated from the loop quantum gravity corrections to the entropy-area law. We also consider an interaction between dark energy and dark matter. The behavior of the Hubble parameter (specially in the late time) is studied. Besides, conditions under which an accelerated universe can decelerate and also successive acceleration-deceleration phases can be occurred in the evolution of the universe is investigated.

  9. Analogue Correction Method of Errors by Combining Statistical and Dynamical Methods

    Institute of Scientific and Technical Information of China (English)

    REN Hongli; CHOU Jifan

    2006-01-01

    Based on the atmospheric analogy principle, the inverse problem that the information of historical analogue data is utilized to estimate model errors is put forward and a method of analogue correction of errors (ACE) of model is developed in this paper. The ACE can combine effectively statistical and dynamical methods, and need not change the current numerical prediction models. The new method not only adequately utilizes dynamical achievements but also can reasonably absorb the information of a great many analogues in historical data in order to reduce model errors and improve forecast skill.Furthermore, the ACE may identify specific historical data for the solution of the inverse problem in terms of the particularity of current forecast. The qualitative analyses show that the ACE is theoretically equivalent to the principle of the previous analogue-dynamical model, but need not rebuild the complicated analogue-deviation model, so has better feasibility and operational foreground. Moreover, under the ideal situations, when numerical models or historical analogues are perfect, the forecast of the ACE would transform into the forecast of dynamical or statistical method, respectively.

  10. Correction

    CERN Document Server

    2002-01-01

    Tile Calorimeter modules stored at CERN. The larger modules belong to the Barrel, whereas the smaller ones are for the two Extended Barrels. (The article was about the completion of the 64 modules for one of the latter.) The photo on the first page of the Bulletin n°26/2002, from 24 July 2002, illustrating the article «The ATLAS Tile Calorimeter gets into shape» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.

  11. [Ventral and dorsal correcting and stabilizing methods in idiopathic scoliosis. Long-term outcome].

    Science.gov (United States)

    Halm, H

    2000-06-01

    The age of standardized instrumented scoliosis correction and stabilization began with Harrington instrumentation (HI). With HI, satisfactory long-term correction of the frontal plane averaged approximately 50%, but without notable derotational capabilities. The distraction of the concavity leads to reduction of the sagittal contour of the spine (flat back), which is biomechanically disadvantageous. The newer multisegmentally attached implant systems avoid this disadvantage. The first prototypes of these systems were Luque- (SSI) Cotrel-Dubousset instrumentation. Ideal indications for posterior instrumented curve correction are structural idiopathic double major curves and flexible single curves. However, even with these newer doublerod systems derotation is low, because derotation is, without any doubt, related to anterior release and thus decoupling of the segments by means of disc resection. The optimum method of correction and stabilization of scoliosis using the anterior approach is the ventral derotation spondylodesis (VDS), according to Zielke, who considers it to be a major improvement over Dwyer instrumentation. VDS is the first implant system with which true three-dimensional, segmental curve correction was made possible. Long term correction of the frontal plane and derotation averages approximately 70% and 50%, respectively. Ideal indications are single lumbar, thoracolumbar and thoracic curves. In our experience, the so-called kyphogenic effect of VDS due to anterior convex compression, can be counteracted by derotation and preserving disc space height with weight bearing bone grafts or cages. The low internal stabilizing capabilities with the risk of rod fracture and pseudarthrosis are unfavorable. They make long term cast or brace treatment necessary postoperatively. Meanwhile, the disadvantage of the low internal stabilizing capabilities of VDS has been overcome with the development of the primary stable Halm-Zielke instrumentation and other primary

  12. On Subextensive Corrections to Fluid Dynamics from Gravity

    CERN Document Server

    Lópes-Cardoso, G; Grass, V

    2010-01-01

    We use the fluid-gravity correspondence to compute subextensive corrections, proportional to the shear tensor, to the energy-momentum tensor of fluids on three-spheres. The dual configurations we consider are charged black hole solutions of N = 2 gauged supergravity theories in five dimensions.

  13. Correction

    CERN Multimedia

    2002-01-01

    The photo on the second page of the Bulletin n°48/2002, from 25 November 2002, illustrating the article «Spanish Visit to CERN» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.   The Spanish delegation, accompanied by Spanish scientists at CERN, also visited the LHC superconducting magnet test hall (photo). From left to right: Felix Rodriguez Mateos of CERN LHC Division, Josep Piqué i Camps, Spanish Minister of Science and Technology, César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology), Juan Antonio Rubio, ETT Division Leader at CERN, Manuel Aguilar-Benitez, Spanish Delegate to Council, Manuel Delfino, IT Division Leader at CERN, and Gonzalo León, Secretary-General of Scientific Policy to the Minister.

  14. Correction

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Regarding Gorelik, G., & Shackelford, T.K. (2011. Human sexual conflict from molecules to culture. Evolutionary Psychology, 9, 564–587: The authors wish to correct an omission in citation to the existing literature. In the final paragraph on p. 570, we neglected to cite Burch and Gallup (2006 [Burch, R. L., & Gallup, G. G., Jr. (2006. The psychobiology of human semen. In S. M. Platek & T. K. Shackelford (Eds., Female infidelity and paternal uncertainty (pp. 141–172. New York: Cambridge University Press.]. Burch and Gallup (2006 reviewed the relevant literature on FSH and LH discussed in this paragraph, and should have been cited accordingly. In addition, Burch and Gallup (2006 should have been cited as the originators of the hypothesis regarding the role of FSH and LH in the semen of rapists. The authors apologize for this oversight.

  15. Non linear field correction effects on the dynamic aperture of the FCC-hh

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00361058; Seryi, Andrei; Maclean, Ewen Hamish; Martin, Roman; Tomas Garcia, Rogelio

    2017-01-01

    The Future Circular Collider (FCC) design study aims to develop the designs of possible circular colliders in the post LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. Given the large beta functions and integrated length of the quadrupoles of the final focus triplet the effect of systematic and random non linear errors in the magnets are expected to have a severe impact on the stability of the beam. Following the experience on the HL-LHC this work explores the implementation of non-linear correctors to minimize the resonance driving terms arising from the errors of the triplet. Dynamic aperture studies are then performed to study the impact of this correction.

  16. Correction

    Directory of Open Access Journals (Sweden)

    2014-01-01

    Full Text Available Regarding Tagler, M. J., and Jeffers, H. M. (2013. Sex differences in attitudes toward partner infidelity. Evolutionary Psychology, 11, 821–832: The authors wish to correct values in the originally published manuscript. Specifically, incorrect 95% confidence intervals around the Cohen's d values were reported on page 826 of the manuscript where we reported the within-sex simple effects for the significant Participant Sex × Infidelity Type interaction (first paragraph, and for attitudes toward partner infidelity (second paragraph. Corrected values are presented in bold below. The authors would like to thank Dr. Bernard Beins at Ithaca College for bringing these errors to our attention. Men rated sexual infidelity significantly more distressing (M = 4.69, SD = 0.74 than they rated emotional infidelity (M = 4.32, SD = 0.92, F(1, 322 = 23.96, p < .001, d = 0.44, 95% CI [0.23, 0.65], but there was little difference between women's ratings of sexual (M = 4.80, SD = 0.48 and emotional infidelity (M = 4.76, SD = 0.57, F(1, 322 = 0.48, p = .29, d = 0.08, 95% CI [−0.10, 0.26]. As expected, men rated sexual infidelity (M = 1.44, SD = 0.70 more negatively than they rated emotional infidelity (M = 2.66, SD = 1.37, F(1, 322 = 120.00, p < .001, d = 1.12, 95% CI [0.85, 1.39]. Although women also rated sexual infidelity (M = 1.40, SD = 0.62 more negatively than they rated emotional infidelity (M = 2.09, SD = 1.10, this difference was not as large and thus in the evolutionary theory supportive direction, F(1, 322 = 72.03, p < .001, d = 0.77, 95% CI [0.60, 0.94].

  17. A method of dynamic chromatic aberration correction in low-voltage scanning electron microscopes.

    Science.gov (United States)

    Khursheed, Anjam

    2005-07-01

    A time-of-flight concept that dynamically corrects for chromatic aberration effects in scanning electron microscopes (SEMs) is presented. The method is predicted to reduce the microscope's chromatic aberration by an order of magnitude. The scheme should significantly improve the spatial resolution of low-voltage scanning electron microscopes (LVSEMs). The dynamic means of correcting for chromatic aberration also allows for the possibility of obtaining high image resolution from electron guns that have relatively large energy spreads.

  18. Correction.

    Science.gov (United States)

    2015-10-01

    In the article by Quintavalle et al (Quintavalle C, Anselmi CV, De Micco F, Roscigno G, Visconti G, Golia B, Focaccio A, Ricciardelli B, Perna E, Papa L, Donnarumma E, Condorelli G, Briguori C. Neutrophil gelatinase–associated lipocalin and contrast-induced acute kidney injury. Circ Cardiovasc Interv. 2015;8:e002673. DOI: 10.1161/CIRCINTERVENTIONS.115.002673.), which published online September 2, 2015, and appears in the September 2015 issue of the journal, a correction was needed. On page 1, the institutional affiliation for Elvira Donnarumma, PhD, “SDN Foundation,” has been changed to read, “IRCCS SDN, Naples, Italy.” The institutional affiliation for Laura Papa, PhD, “Institute for Endocrinology and Experimental Oncology, National Research Council, Naples, Italy,” has been changed to read, “Institute of Genetics and Biomedical Research, Milan Unit, Milan, Italy” and “Humanitas Research Hospital, Rozzano, Italy.” The authors regret this error.

  19. Standard Model-like corrections to Dilatonic Dynamics

    DEFF Research Database (Denmark)

    Antipin, Oleg; Krog, Jens; Mølgaard, Esben

    2013-01-01

    We examine the effects of standard model-like interactions on the near-conformal dynamics of a theory featuring a dilatonic state identified with the standard model-like Higgs. As template for near-conformal dynamics we use a gauge theory with fermionic matter and elementary mesons possessing...... the same non-abelian global symmetries as a technicolor-like theory with matter in a complex representation of the gauge group. We then embed the electroweak gauge group within the global flavor structure and add also ordinary quark-like states to mimic the effects of the top. We find that the standard...

  20. Does Human Milk Modulate Body Composition in Late Preterm Infants at Term-Corrected Age?

    Science.gov (United States)

    Giannì, Maria Lorella; Consonni, Dario; Liotto, Nadia; Roggero, Paola; Morlacchi, Laura; Piemontese, Pasqua; Menis, Camilla; Mosca, Fabio

    2016-10-23

    (1) Background: Late preterm infants account for the majority of preterm births and are at risk of altered body composition. Because body composition modulates later health outcomes and human milk is recommended as the normal method for infant feeding, we sought to investigate whether human milk feeding in early life can modulate body composition development in late preterm infants; (2) Methods: Neonatal, anthropometric and feeding data of 284 late preterm infants were collected. Body composition was evaluated at term-corrected age by air displacement plethysmography. The effect of human milk feeding on fat-free mass and fat mass content was evaluated using multiple linear regression analysis; (3) Results: Human milk was fed to 68% of the infants. According to multiple regression analysis, being fed any human milk at discharge and at  term-corrected and being fed exclusively human milk at term-corrected age were positively associated with fat-free mass content(β = -47.9, 95% confidence interval (CI) = -95.7; -0.18; p = 0.049; β = -89.6, 95% CI = -131.5; -47.7; p milk feeding appears to be associated with fat-free mass deposition in late preterm infants. Healthcare professionals should direct efforts toward promoting and supporting breastfeeding in these vulnerable infants.

  1. Does Human Milk Modulate Body Composition in Late Preterm Infants at Term-Corrected Age?

    Directory of Open Access Journals (Sweden)

    Maria Lorella Giannì

    2016-10-01

    Full Text Available (1 Background: Late preterm infants account for the majority of preterm births and are at risk of altered body composition. Because body composition modulates later health outcomes and human milk is recommended as the normal method for infant feeding, we sought to investigate whether human milk feeding in early life can modulate body composition development in late preterm infants; (2 Methods: Neonatal, anthropometric and feeding data of 284 late preterm infants were collected. Body composition was evaluated at term-corrected age by air displacement plethysmography. The effect of human milk feeding on fat-free mass and fat mass content was evaluated using multiple linear regression analysis; (3 Results: Human milk was fed to 68% of the infants. According to multiple regression analysis, being fed any human milk at discharge and at  term-corrected and being fed exclusively human milk at term-corrected age were positively associated with fat-free mass content(β = −47.9, 95% confidence interval (CI = −95.7; −0.18; p = 0.049; β = −89.6, 95% CI = −131.5; −47.7; p < 0.0001; β = −104.1, 95% CI = −151.4; −56.7, p < 0.0001; (4 Conclusion: Human milk feeding appears to be associated with fat-free mass deposition in late preterm infants. Healthcare professionals should direct efforts toward promoting and supporting breastfeeding in these vulnerable infants.

  2. Long-term patient satisfaction after surgical correction of penile curvature via tunical plication

    Directory of Open Access Journals (Sweden)

    Alvaro Paez

    2007-08-01

    Full Text Available OBJECTIVE: To assess patient satisfaction and functional results at long term follow-up after surgical correction for Peyronie's disease (PD and congenital penile curvature (CPC with the technique of tunical plication. MATERIALS AND METHODS: One hundred and two men operated for PD (n = 76 or CPC (n = 26 in four different departments of urology in public hospitals agreed to answer a six-question telephone questionnaire about treatment satisfaction. Tunica albuginea plication procedures represented the standard surgical approach. Subjects under investigation were correction of the deformity, feeling of bumps under the skin, pain during erection, penile sensory changes, development of erectile dysfunction (ED and postoperative ability for complete vaginal intromission. Subjective response rates were compared using the chi square test on the basis of the etiology of the disease (CPC or PD. RESULTS: Significant differences (p < 0.05 between patients with CPC and PD were noticed in the prevalence of postoperative penile deformity, sensory changes, ED and ability to complete vaginal intromission, PD patients always showing a more pessimistic view. No significant differences (p = ns were detected in terms of unpleasant nodes under the penile skin or pain during erection. CONCLUSIONS: Long-term outcome after surgical correction for PD and CPC with the technique of tunical plication can be poor. Probably patient expectations are above the real performance of surgical techniques. Preoperative information should be more exhaustive.

  3. Understanding the dynamics of correct and error responses in free recall: evidence from externalized free recall.

    Science.gov (United States)

    Unsworth, Nash; Brewer, Gene A; Spillers, Gregory J

    2010-06-01

    The dynamics of correct and error responses in a variant of delayed free recall were examined in the present study. In the externalized free recall paradigm, participants were presented with lists of words and were instructed to subsequently recall not only the words that they could remember from the most recently presented list, but also any other words that came to mind during the recall period. Externalized free recall is useful for elucidating both sampling and postretrieval editing processes, thereby yielding more accurate estimates of the total number of error responses, which are typically sampled and subsequently edited during free recall. The results indicated that the participants generally sampled correct items early in the recall period and then transitioned to sampling more erroneous responses. Furthermore, the participants generally terminated their search after sampling too many errors. An examination of editing processes suggested that the participants were quite good at identifying errors, but this varied systematically on the basis of a number of factors. The results from the present study are framed in terms of generate-edit models of free recall.

  4. Quantum measurement corrections to chemically induced dynamic nuclear polarization

    CERN Document Server

    Kominis, I K

    2013-01-01

    Chemically induced dynamic nuclear polarization has emerged as a universal signature of spin order in photosynthetic reaction centers. Such polarization, significantly enhanced above thermal equilibrium, is known to result from the nuclear spin sorting inherent in the radical pair mechanism underlying long-lived charge-separated states in photosynthetic reaction centers. We will here show that the recently understood fundamental quantum dynamics of radical-ion-pair reactions open up a new and completely unexpected venue towards obtaining CIDNP signals. The fundamental decoherence mechanism inherent in the recombination process of radical pairs is shown to produce nuclear spin polarizations on the order of $10^4$ times or more higher than thermal equilibrium values at low fields relevant to natural photosynthesis in earth's magnetic field. This opens up the possibility of a fundamentally new exploration of the biological significance of high nuclear polarizations in photosynthesis.

  5. Fetal cardiac cine imaging using highly accelerated dynamic MRI with retrospective motion correction and outlier rejection.

    Science.gov (United States)

    van Amerom, Joshua F P; Lloyd, David F A; Price, Anthony N; Kuklisova Murgasova, Maria; Aljabar, Paul; Malik, Shaihan J; Lohezic, Maelene; Rutherford, Mary A; Pushparajah, Kuberan; Razavi, Reza; Hajnal, Joseph V

    2017-04-03

    Development of a MRI acquisition and reconstruction strategy to depict fetal cardiac anatomy in the presence of maternal and fetal motion. The proposed strategy involves i) acquisition and reconstruction of highly accelerated dynamic MRI, followed by image-based ii) cardiac synchronization, iii) motion correction, iv) outlier rejection, and finally v) cardiac cine reconstruction. Postprocessing entirely was automated, aside from a user-defined region of interest delineating the fetal heart. The method was evaluated in 30 mid- to late gestational age singleton pregnancies scanned without maternal breath-hold. The combination of complementary acquisition/reconstruction and correction/rejection steps in the pipeline served to improve the quality of the reconstructed 2D cine images, resulting in increased visibility of small, dynamic anatomical features. Artifact-free cine images successfully were produced in 36 of 39 acquired data sets; prolonged general fetal movements precluded processing of the remaining three data sets. The proposed method shows promise as a motion-tolerant framework to enable further detail in MRI studies of the fetal heart and great vessels. Processing data in image-space allowed for spatial and temporal operations to be applied to the fetal heart in isolation, separate from extraneous changes elsewhere in the field of view. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  6. Fermionic corrections to fluid dynamics from BTZ black hole

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, L.G.C. [DISIT, Università del Piemonte Orientale,via T. Michel, 11, Alessandria, 15120 (Italy); Dipartimento di Fisica “Galileo Galilei”,Università di Padova, via Marzolo 8, 35131 Padova (Italy); INFN - Sezione di Padova,via Marzolo 8, 35131, Padova (Italy); Grassi, P.A. [DISIT, Università del Piemonte Orientale,via T. Michel, 11, Alessandria, 15120 (Italy); INFN - Gruppo Collegato di Alessandria, Sezione di Torino,Alessandria (Italy); PH-TH Department, CERN,CH-1211 Geneva 23 (Switzerland); Mezzalira, A. [Dipartimento di Fisica Teorica, Università di Torino,via P. Giuria, 1, Torino, 10125 (Italy); INFN - Gruppo Collegato di Alessandria, Sezione di Torino,Alessandria (Italy)

    2015-11-23

    We reconstruct the complete fermionic orbit of the non-extremal BTZ black hole by acting with finite supersymmetry transformations. The solution satisfies the exact supergravity equations of motion to all orders in the fermonic expansion and the final result is given in terms of fermionic bilinears. By fluid/gravity correspondence, we derive linearized Navier-Stokes equations and a set of new differential equations from Rarita-Schwinger equation. We compute the boundary energy-momentum tensor and we interpret the result as a perfect fluid with a modified definition of fluid velocity. Finally, we derive the modified expression for the entropy of the black hole in terms of the fermionic bilinears.

  7. Long-Term Dynamics of Autonomous Fractional Differential Equations

    Science.gov (United States)

    Liu, Tao; Xu, Wei; Xu, Yong; Han, Qun

    This paper aims to investigate long-term dynamic behaviors of autonomous fractional differential equations with effective numerical method. The long-term dynamic behaviors predict where systems are heading after long-term evolution. We make some modification and transplant cell mapping methods to autonomous fractional differential equations. The mapping time duration of cell mapping is enlarged to deal with the long memory effect. Three illustrative examples, i.e. fractional Lotka-Volterra equation, fractional van der Pol oscillator and fractional Duffing equation, are studied with our revised generalized cell mapping method. We obtain long-term dynamics, such as attractors, basins of attraction, and saddles. Compared with some existing stability and numerical results, the validity of our method is verified. Furthermore, we find that the fractional order has its effect on the long-term dynamics of autonomous fractional differential equations.

  8. Analog VLSI Circuits for Short-Term Dynamic Synapses

    Directory of Open Access Journals (Sweden)

    Shih-Chii Liu

    2003-06-01

    Full Text Available Short-term dynamical synapses increase the computational power of neuronal networks. These synapses act as additional filters to the inputs of a neuron before the subsequent integration of these signals at its cell body. In this work, we describe a model of depressing and facilitating synapses derived from a hardware circuit implementation. This model is equivalent to theoretical models of short-term synaptic dynamics in network simulations. These circuits have been added to a network of leaky integrate-and-fire neurons. A cortical model of direction-selectivity that uses short-term dynamic synapses has been implemented with this network.

  9. The Effect of Dynamic Written Corrective Feedback on Iranian Elementary Learners’ Writing

    Directory of Open Access Journals (Sweden)

    Amaneh Kamalian

    2014-09-01

    Full Text Available Error correction is probably the most widely used technique for responding to students’ writing. Although many studies have attempted to investigate the efficacy of providing error correction through different types of written corrective feedback (WCF, there has been relatively little research on any one new approach to writing pedagogy in foreign language learning which is called dynamic WCF. The purpose of the current research was to test the effect of WCF on the improvement of writing abilities of EFL learners. Two groups of EFL students who were learning English as a foreign language participated in this study. Both groups (A and B were given treatments. Core components of the treatment included having the students to write a composition every session (twice a week and the teacher providing the students with feedbacks (dynamic WCF or direct WCF on their writing tasks. Group A (n=24 was instructed through dynamic WCF because it was intended to improve L2 writing ability in general by raising linguistic awareness of learners through the error corrections performed by the teacher.  On the other hand, group B (n= 22 received direct WCF on their writings. Four essential characteristics were taken into consideration for the error correction, i.e. feedback needed to be manageable, meaningful, timely and constant. The data obtained for Group A and Group B was analyzed using paired sample test and the results indicated that both groups had improved on their writing abilities. Also, administrating an independent sample T-test the findings revealed that Group A which received dynamic WCF could outperform Group B. Keywords: corrective feedback; dynamic written corrective feedback; direct error correction

  10. An Analog Gamma Correction Scheme for High Dynamic Range CMOS Logarithmic Image Sensors

    Directory of Open Access Journals (Sweden)

    Yuan Cao

    2014-12-01

    Full Text Available In this paper, a novel analog gamma correction scheme with a logarithmic image sensor dedicated to minimize the quantization noise of the high dynamic applications is presented. The proposed implementation exploits a non-linear voltage-controlled-oscillator (VCO based analog-to-digital converter (ADC to perform the gamma correction during the analog-to-digital conversion. As a result, the quantization noise does not increase while the same high dynamic range of logarithmic image sensor is preserved. Moreover, by combining the gamma correction with the analog-to-digital conversion, the silicon area and overall power consumption can be greatly reduced. The proposed gamma correction scheme is validated by the reported simulation results and the experimental results measured for our designed test structure, which is fabricated with 0.35 μm standard complementary-metal-oxide-semiconductor (CMOS process.

  11. Leading-order cross term correction of three-dimensional parabolic equation models.

    Science.gov (United States)

    Sturm, Frédéric

    2016-01-01

    The issue of handling a leading-order cross-multiplied term in three-dimensional (3D) parabolic equation (PE) based models is addressed. In particular, numerical results obtained incorporating a leading-order cross-term correction in an existing 3D PE model, written in cylindrical coordinates, based on higher-order Padé approximations in both depth and azimuth, and a splitting operator technique are reported. Note that the numerical algorithm proposed in this paper could be used in the future to update any 3D PE codes that neglect cross terms and use a splitting numerical technique. The 3D penetrable wedge benchmark problem is chosen to illustrate the accuracy of the now-fully wide-angle enhanced 3D PE model. The comparisons with a 3D reference solution based on the image source clearly show that handling the leading-order cross term in the 3D PE computation is sufficient to remove the phase errors inherent to any 3D PE models that neglect cross terms in their formulations.

  12. Object image correction using an X-ray dynamical diffraction Fraunhofer hologram.

    Science.gov (United States)

    Balyan, Minas K

    2014-03-01

    Taking into account background correction and using Fourier analysis, a numerical method of an object image correction using an X-ray dynamical diffraction Fraunhofer hologram is presented. An example of the image correction of a cylindrical beryllium wire is considered. A background correction of second-order iteration leads to an almost precise reconstruction of the real part of the amplitude transmission coefficient and improves the imaginary part compared with that without a background correction. Using Fourier analysis of the reconstructed transmission coefficient, non-physical oscillations can be avoided. This method can be applied for the determination of the complex amplitude transmission coefficient of amplitude as well as phase objects, and can be used in X-ray microscopy.

  13. A Phillips curve interpretation of error-correction models of the wage and price dynamics

    DEFF Research Database (Denmark)

    Harck, Søren H.

     This paper presents a model of employment, distribution and inflation in which a modern error correction specification of the nominal wage and price dynamics (referring to claims on income by workers and firms) occupies a prominent role. It is brought out, explicitly, how this rather typical error......-correction setting, which actually seems to capture the wage and price dynamics of many large- scale econometric models quite well, is fully compatible with the notion of an old-fashioned Phillips curve with finite slope. It is shown how the steady-state impact of various shocks to the model can be profitably...

  14. A Phillips curve interpretation of error-correction models of the wage and price dynamics

    DEFF Research Database (Denmark)

    Harck, Søren H.

    2009-01-01

    This paper presents a model of employment, distribution and inflation in which a modern error correction specification of the nominal wage and price dynamics (referring to claims on income by workers and firms) occupies a prominent role. It is brought out, explicitly, how this rather typical error......-correction setting, which actually seems to capture the wage and price dynamics of many large- scale econometric models quite well, is fully compatible with the notion of an old-fashioned Phillips curve with finite slope. It is shown how the steady-state impact of various shocks to the model can be profitably...

  15. Dynamical corrections to the anomalous holographic soft-wall model: the pomeron and the odderon

    Energy Technology Data Exchange (ETDEWEB)

    Capossoli, Eduardo Folco [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Colegio Pedro II, Departamento de Fisica, Rio de Janeiro, RJ (Brazil); Li, Danning [Institute of Theoretical Physics, Chinese Academy of Science (ITP, CAS), Beijing (China); Boschi-Filho, Henrique [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2016-06-15

    In this work we use the holographic soft-wall AdS/QCD model with anomalous dimension contributions coming from two different QCD beta functions to calculate the masses of higher spin glueball states for both even and odd spins and their Regge trajectories, related to the pomeron and the odderon, respectively. We further investigate this model taking into account dynamical corrections due to a dilaton potential consistent with the Einstein equations in five dimensions. The results found in this work for the Regge trajectories within the anomalous soft-wall model with dynamical corrections are consistent with those present in the literature. (orig.)

  16. The generation algorithm of arbitrary polygon animation based on dynamic correction

    Directory of Open Access Journals (Sweden)

    Hou Ya Wei

    2016-01-01

    Full Text Available This paper, based on the key-frame polygon sequence, proposes a method that makes use of dynamic correction to develop continuous animation. Firstly we use quadratic Bezier curve to interpolate the corresponding sides vector of polygon sequence consecutive frame and realize the continuity of animation sequences. And then, according to Bezier curve characteristic, we conduct dynamic regulation to interpolation parameters and implement the changing smoothness. Meanwhile, we take use of Lagrange Multiplier Method to correct the polygon and close it. Finally, we provide the concrete algorithm flow and present numerical experiment results. The experiment results show that the algorithm acquires excellent effect.

  17. Dynamical corrections to the anomalous holographic softwall model: the pomeron and the odderon

    CERN Document Server

    Capossoli, Eduardo Folco; Boschi-Filho, Henrique

    2016-01-01

    In this work we use the holographic softwall AdS/QCD model with anomalous dimension contributions coming from two different QCD beta functions to calculate the masses of higher spin glueball states for both even and odd spins and its respective Regge trajectories, related to the pomeron and the odderon, respectively. We further investigate this model taking into account dynamical corrections due to a dilaton potential consistent with Einstein equations in 5 dimensions. The results found in this work for the Regge trajectories within the anomalous softwall model with dynamical corrections are consistent with those presented in the literature.

  18. Long Term Incentives for Residential Customers Using Dynamic Tariff

    DEFF Research Database (Denmark)

    Huang, Shaojun; Wu, Qiuwei; Nielsen, Arne Hejde

    2015-01-01

    This paper reviews several grid tariff schemes, including flat tariff, time-of-use, time-varying tariff, demand charge and dynamic tariff (DT), from the perspective of the long term incentives. The long term incentives can motivate the owners of flexible demands to change their energy consumption...

  19. Effects of Quantum Correction on Dynamical Phase Transition in a Single Species Bosonic Josephson Junction

    Institute of Scientific and Technical Information of China (English)

    TIAN Jing; QIU Hai-Bo

    2013-01-01

    In this paper,by employing Bogliubov backreaction method,we investigate quantum correction effects on dynamical phase transition in a single species bosonic Josephson junction induced by increasing nonlinear interaction.Compared with mean field theory results,we find that the transition point is shifted.The dynamical phase transition is accompanied by a change of the entanglement entropy,which is found to reach a maximum at the transition point of the mean field theory.

  20. Aphakia correction with retropupillary fixated iris-claw lens (Artisan – long-term results

    Directory of Open Access Journals (Sweden)

    Schallenberg M

    2013-12-01

    Full Text Available Maurice Schallenberg,1,2 Dirk Dekowski,1 Angela Hahn,1 Thomas Laube,1,3 Klaus-Peter Steuhl,1 Daniel Meller11Department of Ophthalmology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; 2HELIOS Klinikum Wuppertal, Wuppertal, Germany; 3Zentrum für Augenheilkunde PD Dr Laube, Düsseldorf, GermanyPurpose: To evaluate the technique, safety, and efficacy of the retropupillary implantation of iris-claw intraocular lenses in a long-term follow-up study.Patients and methods: This retrospective study included 31 eyes of 31 patients who underwent an Artisan aphakic intraocular lens implantation between January 2006 and February 2011 at the University Hospital Essen, Essen, Germany and at the Zentrum für Augenheilkunde PD Dr Laube, Düsseldorf, Germany. Preoperative data collected included demographics, etiology of aphakia, previous surgeries, preoperative eye pathology, intraocular pressure, clinical signs of endothelial cell loss, and best corrected visual acuity. Operative data and postoperative outcomes included the best corrected visual acuity, lens position, intraocular pressure, pigment dispersion, clinical signs of endothelial cell loss, development of macular edema, and other complications.Results: Thirty-one patients were included. The mean follow-up was 25.2 months (range: 4–48 months. The mean best corrected visual acuity postoperatively was 0.64 logarithm of the minimum angle of resolution (logMAR and varied from 0 logMAR to 3 logMAR. Some patients had a low visual acuity preoperatively because of preoperative eye pathologies. In 22 patients the visual acuity improved, in two patients the visual acuity remained unchanged, and seven patients showed a decreased visual acuity. Complications were peaked pupils (n=10 and retinal detachment in one case. Four patients showed an iris atrophy and high intraocular pressure was observed only in one patient. Subluxation of the intraocular lens, endothelial cell loss, and

  1. Error suppression and error correction in adiabatic quantum computation: non-equilibrium dynamics

    Science.gov (United States)

    Sarovar, Mohan; Young, Kevin C.

    2013-12-01

    While adiabatic quantum computing (AQC) has some robustness to noise and decoherence, it is widely believed that encoding, error suppression and error correction will be required to scale AQC to large problem sizes. Previous works have established at least two different techniques for error suppression in AQC. In this paper we derive a model for describing the dynamics of encoded AQC and show that previous constructions for error suppression can be unified with this dynamical model. In addition, the model clarifies the mechanisms of error suppression and allows the identification of its weaknesses. In the second half of the paper, we utilize our description of non-equilibrium dynamics in encoded AQC to construct methods for error correction in AQC by cooling local degrees of freedom (qubits). While this is shown to be possible in principle, we also identify the key challenge to this approach: the requirement of high-weight Hamiltonians. Finally, we use our dynamical model to perform a simplified thermal stability analysis of concatenated-stabilizer-code encoded many-body systems for AQC or quantum memories. This work is a companion paper to ‘Error suppression and error correction in adiabatic quantum computation: techniques and challenges (2013 Phys. Rev. X 3 041013)’, which provides a quantum information perspective on the techniques and limitations of error suppression and correction in AQC. In this paper we couch the same results within a dynamical framework, which allows for a detailed analysis of the non-equilibrium dynamics of error suppression and correction in encoded AQC.

  2. [The effectiveness of dynamic proprioceptive correction in patients with cerebral palsy with cognitive impairment].

    Science.gov (United States)

    Nemkova, S A; Maslova, O I

    2013-01-01

    One hundred and sixty-seven patients with cerebral palsy (CP), aged 11-16 years, with spastic diplegia (n=87) and hemiparetic forms (n=80), with subgroups of mental retardation (MR) or intellectual delay (ID) have been studied. Standard treatment and application of a method of dynamic proprioceptive correction (MDPC) in the complex rehabilitation with the use of a medical and loading Adeli suit were used. Cognitive deficit in patients was characterized by the relative integrity of short-term nonverbal memory and marked impairment of verbal memory, verbal and nonverbal intellect. CP patients with intellectual delay demonstrated the predominant impairment of verbal functions. CP patients with mental retardation have the deficiency of both verbal and non-verbal cognitive functions. An individual profile of brain functional asymmetry in patients with CP was more lateralized than in healthy peers that can represent a mechanism for irregular development of cognitive functions in CP. Implementing the MDPC into comprehensive rehabilitation promotes the improvement of postural regulation and cognitive functions in children with CP compared to traditional methods of treatment. This is accompanied by the changes in functioning of the associative brain areas and hemispheric interaction.

  3. Static and Dynamic Parameters in Patients With Degenerative Flat Back and Change After Corrective Fusion Surgery.

    Science.gov (United States)

    Lee, Jung Hwan; Lee, Sang-Ho

    2016-08-01

    To evaluate characteristics of static and dynamic parameters in patients with degenerative flat back (DFB) and to compare degree of their improvement between successful and unsuccessful surgical outcome groups. Forty-seven patients with DFB were included who took whole spine X-ray and three-dimensional motion analysis before and 6 months after corrective surgery. Forty-four subjects were selected as a control group. As static parameters, thoracic kyphosis (TK), thoracolumbar junction (TLJ), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured. As dynamic parameters, maximal and minimal angle of pelvic tilt, lower limb joints, and thoracic and lumbar vertebrae column (dynamic TK and LL) in sagittal plane were obtained. The DFB group showed smaller TK and larger LL, pelvic posterior tilt, hip flexion, knee flexion, and ankle dorsiflexion than the control group. Most of these parameters were significantly corrected by fusion surgery. Dynamic spinal parameters correlated with static spinal parameters. The successful group obtained significant improvement in maximal and minimal dynamic LL than the unsuccessful group. The DFB group showed characteristic lower limb and spinal angles in dynamic and static parameters. Correlation between static and dynamic parameters was found in spinal segment. Dynamic LL was good predictor of successful surgical outcomes.

  4. A Hierarchical Bayes Error Correction Model to Explain Dynamic Effects of Price Changes

    NARCIS (Netherlands)

    D. Fok (Dennis); R. Paap (Richard); C. Horváth (Csilla); Ph.H.B.F. Franses (Philip Hans)

    2005-01-01

    textabstractThe authors put forward a sales response model to explain the differences in immediate and dynamic effects of promotional prices and regular prices on sales. The model consists of a vector autoregression rewritten in error-correction format which allows to disentangle the immediate

  5. The dynamics of entry, exit and profitability: an error correction approach for the retail industry

    NARCIS (Netherlands)

    M.A. Carree (Martin); A.R. Thurik (Roy)

    1994-01-01

    textabstractWe develop a two equation error correction model to investigate determinants of and dynamic interaction between changes in profits and number of firms in retailing. An explicit distinction is made between the effects of actual competition among incumbants, new firms competition and poten

  6. A Hierarchical Bayes Error Correction Model to Explain Dynamic Effects of Price Changes

    NARCIS (Netherlands)

    D. Fok (Dennis); R. Paap (Richard); C. Horváth (Csilla); Ph.H.B.F. Franses (Philip Hans)

    2005-01-01

    textabstractThe authors put forward a sales response model to explain the differences in immediate and dynamic effects of promotional prices and regular prices on sales. The model consists of a vector autoregression rewritten in error-correction format which allows to disentangle the immediate effec

  7. Long-term outcome of surgical Class III correction as a function of age at surgery

    Science.gov (United States)

    Bailey, L'Tanya J.; Phillips, Ceib; Proffit, William R.

    2009-01-01

    Introduction In this study, we assessed whether the likelihood of a positive overjet 5 to 10 years after Class III surgery was affected by age at the surgery or the type of surgery and evaluated the amount and pattern of postsurgical growth. Methods Cephalometric measurements including overjet were evaluated from immediately postsurgery and long-term recall cephalograms of 104 patients who had had surgical Class III correction and at least 5-year recalls. The patients were classified as younger (term changes in overjet and other cephalometric characteristics in the younger and the older patients were similar. No patients in the sample had negative overjet in the long term, but zero overjet (<1 mm) was observed in some patients in all groups. Patients who had mandibular setback at any age were 2.6 times more likely to have zero overjet in the long term (P = .003) than those with maxillary surgery alone. For the younger patients, the likelihood of zero overjet in the long term was not significantly different from patients who were treated later (P = .87), with or without mandibular surgery. Conclusions The data support the use of serial cephalometric radiographs, with surgery deferred until little or no mandibular growth is observed, to determine the timing of Class III surgery in younger patients. PMID:18331934

  8. Deepbite correction with incisor intrusion in adults: a long-term cephalometric study.

    Science.gov (United States)

    Kale Varlık, Selin; Onur Alpakan, Ödül; Türköz, Çağrı

    2013-09-01

    The purpose of this study was to investigate the long-term stability of deep overbite correction with mandibular incisor intrusion with utility arches in adult patients. Pretreatment, posttreatment, and 5-years postretention lateral cephalograms of 31 patients (mean age, 26.8 years; range, 24.1-30.9 years) with Class II Division 1 malocclusion and deepbite, treated by maxillary first premolar extraction and mandibular incisor intrusion, were traced and measured. Significant decreases in overjet and overbite (6.4 ± 1.2 and 3.9 ± 0.7 mm, respectively), significant retroclination (17° ± 1.9°) and retraction (3.8 ± 1.1 mm) of the maxillary incisors, and significant increases in protrusion (0.8 ± 1.5 mm), proclination (0.6° ± 0.9°), and intrusion (2.6 ± 1.4 mm) of the mandibular incisors were observed at posttreatment. At postretention, there were statistically significant but clinically unimportant increases in overjet and overbite (0.4 ± 0.2 and 0.8 ± 0.4 mm, respectively) and extrusion of the mandibular incisors (0.8 ± 1.1 mm). Correction of deepbite in nongrowing patients by mandibular incisor intrusion with a utility arch can be considered effective and stable. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  9. Cosmological dynamics of scalar fields with kinetic corrections: Beyond the exponential potential

    CERN Document Server

    Dutta, Jibitesh; Tamanini, Nicola

    2016-01-01

    We expand the dynamical systems investigation of cosmological scalar fields characterised by kinetic corrections presented in [N. Tamanini, Phys. Rev. D 89 (2014) 083521]. In particular we do not restrict the analysis to exponential potentials only, but we consider arbitrary scalar field potentials and derive general results regarding the corresponding cosmological dynamics. Two specific potentials are then used as examples to show how these models can be employed not only to describe dark energy, but also to achieve dynamical crossing of the phantom barrier at late times. Stability and viability issues at the classical level are also discussed.

  10. A novel energy conversion based method for velocity correction in molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hanhui [School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027 (China); Collaborative Innovation Center of Advanced Aero-Engine, Hangzhou 310027 (China); Liu, Ningning [School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027 (China); Ku, Xiaoke, E-mail: xiaokeku@zju.edu.cn [School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027 (China); Fan, Jianren [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China)

    2017-05-01

    Molecular dynamics (MD) simulation has become an important tool for studying micro- or nano-scale dynamics and the statistical properties of fluids and solids. In MD simulations, there are mainly two approaches: equilibrium and non-equilibrium molecular dynamics (EMD and NEMD). In this paper, a new energy conversion based correction (ECBC) method for MD is developed. Unlike the traditional systematic correction based on macroscopic parameters, the ECBC method is developed strictly based on the physical interaction processes between the pair of molecules or atoms. The developed ECBC method can apply to EMD and NEMD directly. While using MD with this method, the difference between the EMD and NEMD is eliminated, and no macroscopic parameters such as external imposed potentials or coefficients are needed. With this method, many limits of using MD are lifted. The application scope of MD is greatly extended.

  11. Conformal optical design with combination of static and dynamic aberration corrections

    Institute of Scientific and Technical Information of China (English)

    Li Yan; Li Lin; Huang Yi-Fan; Liu Jia-Guo

    2009-01-01

    Conformal domes that are shaped to meet aerodynamic requirements can increase range and speed for the host platform. Because these domes typically deviate greatly from spherical surface descriptions, a variety of aberrations are induced which vary with the field-of-regard (FOR) angle. A system for correcting optical aberrations created by a conformal dome has an outer surface and an inner surface. Optimizing the inner surface is regard as static aberration correction. A deformable mirror is placed at the position of the secondary mirror in the two-mirror all reflective imaging system, which is the dynamic aberration correction. An ellipsoidal MgF2 conformal dome with a fineness ratio of 1.0 is designed as an example. The FOR angle is 00°-30°, and the design wavelength is 4 μm. After the optimization at 7zoom positions by using the design tools Code V, the root-mean-square (RMS) spot size is reduced to approximately 0.99 to 1.48 times the diffraction limit. The design results show that the performances of the conformal optical systems can be greatly improved by the combination of the static correction and the dynamic correction.

  12. Formulation of quantized Hamiltonian dynamics in terms of natural variables.

    Science.gov (United States)

    Akimov, Alexey V; Prezhdo, Oleg V

    2012-12-14

    We present a formulation of quantized Hamiltonian dynamics (QHD) using variables that arise naturally from the Heisenberg equation of motion. The QHD equations are obtained and solved either directly in terms of these generalized variables, or by employing a wavefunction ansatz. The approach avoids a Taylor expansion and other approximations to the potential, leading to more stable dynamics and a higher precision of the calculated quantities. The proposed formulation is also amenable to for analytic and numerical implementations, thus facilitating its use in molecular dynamics simulation.

  13. On the non-Gaussian corrections in the self dynamics of semi-quantum fluids

    Energy Technology Data Exchange (ETDEWEB)

    Colognesi, D., E-mail: daniele.colognesi@isc.cnr.it [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Bafile, U.; Celli, M. [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Neumann, M. [Fakultät für Physik der Universität Wien, Strudlhofgasse 4, A-1090 Wien (Austria)

    2015-01-13

    Highlights: • We study the Gaussian approximation in the self dynamics of semi-quantum liquids. • Correction scheme for the self intermediate scattering function is proposed. • Deviations from the Gaussian approximation are calculated in liquid H{sub 2}. • Experimental data confirm our approach and show that corrections are necessary. - Abstract: This paper is devoted to the study of the limits of the well-known Gaussian approximation in the self dynamics of quantum systems. After introducing the basic formalism and shortly reviewing the methods used in classical systems to apply corrections to the Gaussian approximation, an extension to quantum fluids is devised, with a particular interest in the so-called semi-quantum fluids, i.e. those in which the single particle momentum distribution approximately retains its Maxwellian form (but not its classical width). In this case a detailed correction scheme for both the short- and the long-time behaviors of the intermediate scattering function is proposed. Subsequently, a practical test of this approach is performed on a high resolution neutron scattering spectrum derived from liquid parahydrogen at T=14.1 K. Extracting the spectral deviations from the Gaussian approximation with the help of an accurate centroid molecular dynamics simulation, we are able to describe them precisely and to derive the first two correction coefficients in this system by means of a simple fitting procedure. These experimental findings confirm the validity of our approach and show that a description of the self dynamics beyond the Gaussian approximation is necessary even in simple liquids affected by mild quantum effects.

  14. [Long-term results of two temporalis muscle transfer procedures in correction of paralytic lagophthalmos].

    Science.gov (United States)

    Qian, Jiange; Yan, Liangbin; Zhang, Guocheng

    2004-11-01

    To compare the long-term results and possible complications of a modified temporalis muscle transfer (TMT) with the Johnson's procedure in correction of paralytic lagophthalmos. From September 1997 to March 2000, paralytic lagophthalmos due to leprosy in 92 patients were corrected with TMT. The 89 cases (127 to eyes including 51 unilateral and 38 bilateral) followed up 3 years after operation were analyzed. There were 69 males and 20 females with ages ranging from 18 to 65 years (52 years on average). The duration of lagophthalmos was 1-22 years with an average of 8.2 years. And 36 eyes were complicated with lower eyelid ectropion. Sixty-five eyes were corrected with Johnson's procedure (Johnson's TMT group), 62 with the modified TMT procedure (modified TMT group). The modifications were as follows: (1) omitting the fascial strip in the lower eyelid to avoid postoperative ectropion. (2) fixing the fascial strip of the upper eyelid to the middle or inner margin of the tarsal palate depending on the degree of the lagophthalmos to avoid possible ptosis of the upper eyelid. In Johnson's TMT group, the mean lid gap on light closure was reduced to 3.1 mm postoperatively from 7.7 mm preoperatively; and the mean lid gap on tight closure was reduced to 0.5 mm postoperatively from 6.1 mm preoperatively. The symptoms of redness (73.7%) and tearing (63.7%) disappeared or were improved postoperatively. However, ectropion and ptosis occurred in 24 eyes and 9 eyes respectively. The overall excellent and good rate was 58.5%. In the modified TMT group, the mean lid gap on light closure was reduced to 3.3 mm postoperatively from 7.5 mm preoperatively; and the mean lid gap on tight closure was reduced to 0. 6 mm postoperatively from 6. 3 mm preoperatively. The symptoms of redness (90.9%) and tearing (71.0%) disappeared or were improved postoperatively, and no ectropion or ptosis was found except one ectropion. The overall excellent and good rate was 87.1%, which was significantly

  15. Quintessence dynamics with two scalar fields and mixed kinetic terms

    CERN Document Server

    van de Bruck, Carsten

    2009-01-01

    The dynamical properties of a model of dark energy in which two scalar fields are coupled by a non-canonical kinetic term are studied. We show that overall the addition of the coupling has only minor effects on the dynamics of the two-field system for both potentials studied, even preserving many of the features of the assisted quintessence scenario. The coupling of the kinetic terms enlarges the regions of stability of the critical points. When the potential is of an additive form, we find the kinetic coupling has an interesting effect on the dynamics of the fields as they approach the inflationary attractor, with the result that the combined equation of state of the scalar fields can approach -1 during the transition from a matter dominated universe to the recent period of acceleration.

  16. Shepherd's Crook Deformity of Polyostotic Fibrous Dysplasia Treated with Corrective Osteotomy and Dynamic Hip Screw

    Directory of Open Access Journals (Sweden)

    Wei-Jen Chen

    2005-07-01

    Full Text Available Fibrous dysplasia, a condition in which the skeleton fails to develop normally, is characterized by fibroblastic stroma and immature bone. Bowing of the long bones occurs frequently in the polyostotic form, and stress fractures often result. Shepherd's crook deformity is a characteristic feature of fibrous dysplasia. The goal of its treatment is to obtain normal walking ability and relieve pain due to pathologic fracture secondary to the deformity; however, correction of the deformity is a surgical challenge. We present 2 cases of shepherd's crook deformity treated with corrective osteotomy and a dynamic hip screw. Both cases showed good bone healing and no recurrent deformity. The gross deformities were corrected, and both patients were pain-free after operation.

  17. Efficient dynamical correction of the transition state theory rate estimate for a flat energy barrier.

    Science.gov (United States)

    Mökkönen, Harri; Ala-Nissila, Tapio; Jónsson, Hannes

    2016-09-07

    The recrossing correction to the transition state theory estimate of a thermal rate can be difficult to calculate when the energy barrier is flat. This problem arises, for example, in polymer escape if the polymer is long enough to stretch between the initial and final state energy wells while the polymer beads undergo diffusive motion back and forth over the barrier. We present an efficient method for evaluating the correction factor by constructing a sequence of hyperplanes starting at the transition state and calculating the probability that the system advances from one hyperplane to another towards the product. This is analogous to what is done in forward flux sampling except that there the hyperplane sequence starts at the initial state. The method is applied to the escape of polymers with up to 64 beads from a potential well. For high temperature, the results are compared with direct Langevin dynamics simulations as well as forward flux sampling and excellent agreement between the three rate estimates is found. The use of a sequence of hyperplanes in the evaluation of the recrossing correction speeds up the calculation by an order of magnitude as compared with the traditional approach. As the temperature is lowered, the direct Langevin dynamics simulations as well as the forward flux simulations become computationally too demanding, while the harmonic transition state theory estimate corrected for recrossings can be calculated without significant increase in the computational effort.

  18. Efficient dynamical correction of the transition state theory rate estimate for a flat energy barrier

    Science.gov (United States)

    Mökkönen, Harri; Ala-Nissila, Tapio; Jónsson, Hannes

    2016-09-01

    The recrossing correction to the transition state theory estimate of a thermal rate can be difficult to calculate when the energy barrier is flat. This problem arises, for example, in polymer escape if the polymer is long enough to stretch between the initial and final state energy wells while the polymer beads undergo diffusive motion back and forth over the barrier. We present an efficient method for evaluating the correction factor by constructing a sequence of hyperplanes starting at the transition state and calculating the probability that the system advances from one hyperplane to another towards the product. This is analogous to what is done in forward flux sampling except that there the hyperplane sequence starts at the initial state. The method is applied to the escape of polymers with up to 64 beads from a potential well. For high temperature, the results are compared with direct Langevin dynamics simulations as well as forward flux sampling and excellent agreement between the three rate estimates is found. The use of a sequence of hyperplanes in the evaluation of the recrossing correction speeds up the calculation by an order of magnitude as compared with the traditional approach. As the temperature is lowered, the direct Langevin dynamics simulations as well as the forward flux simulations become computationally too demanding, while the harmonic transition state theory estimate corrected for recrossings can be calculated without significant increase in the computational effort.

  19. On the Accuracy of the GN-Model and on Analytical Correction Terms to Improve It

    CERN Document Server

    Carena, A; Curri, V; Jiang, Y; Poggiolini, P; Forghieri, F

    2014-01-01

    The GN-model has been proposed to provide an approximate but sufficiently accurate tool for predicting uncompensated optical system performance, in realistic scenarios. For this specific use, the GN-model has enjoyed substantial validation, both simulative and experimental. Recently, however, it has been pointed out that its predictions, when used to obtain a detailed physical picture of non-linear noise accumulation along a link, may be affected by substantial error. In addition, it has been pointed out that part of the non-linear interference (NLI) noise variance that it predicts may be ascribed to long-correlation phase noise rather than quasi-additive Gaussian noise. We analyze in detail the GN-model errors and the analytical correction terms that have been proposed to remove them. We extend such analytical results to single-channel non-linearity, and provide integral formulas for both single and cross-channel effects. We carry out a simulative in-depth characterization of phase noise in realistic links. ...

  20. Long-term dynamical evolution of dusty ejecta from Deimos

    Science.gov (United States)

    Makuch, Martin; Krivov, Alexander V.; Spahn, Frank

    2005-04-01

    We re-assess expected properties of the presumed dust belt of Mars formed by impact ejecta from Deimos. Previous studies have shown that dynamics of Deimos particles are dominated by two perturbing forces: radiation pressure (RP) and Mars' oblateness (J2). At the same time, they have demonstrated that lifetimes of particles, especially of grains about ten of micrometers in size, may reach more than 104 years. On such timescales, the Poynting-Robertson drag (PR) becomes important. Here we provide a study of the dynamics under the combined action of all three perturbing forces. We show that a PR decay of the semimajor axes leads to an adiabatic decrease of amplitudes and periods of oscillations in orbital inclinations predicted in the framework of the underlying RP+J2 problem. Furthermore, we show that smallest of the long-lived Deimos grains (radius≈5- 10μm) may reach a chaotic regime, resulting in unpredictable and abrupt changes of their dynamics. The particles just above that size ( ≈10- 15μm) should be the most abundant in the Deimos torus. Our dynamical analysis, combined with a more accurate study of the particle lifetimes, provides corrections to earlier predictions about the dimensions and geometry of the Deimos torus. In addition to a population, appreciably inclined and shifted towards the Sun, the torus should contain a more contracted, less asymmetric, and less tilted component between the orbits of Phobos and Deimos.

  1. Identifying influential nodes in dynamic social networks based on degree-corrected stochastic block model

    Science.gov (United States)

    Wang, Tingting; Dai, Weidi; Jiao, Pengfei; Wang, Wenjun

    2016-05-01

    Many real-world data can be represented as dynamic networks which are the evolutionary networks with timestamps. Analyzing dynamic attributes is important to understanding the structures and functions of these complex networks. Especially, studying the influential nodes is significant to exploring and analyzing networks. In this paper, we propose a method to identify influential nodes in dynamic social networks based on identifying such nodes in the temporal communities which make up the dynamic networks. Firstly, we detect the community structures of all the snapshot networks based on the degree-corrected stochastic block model (DCBM). After getting the community structures, we capture the evolution of every community in the dynamic network by the extended Jaccard’s coefficient which is defined to map communities among all the snapshot networks. Then we obtain the initial influential nodes of the dynamic network and aggregate them based on three widely used centrality metrics. Experiments on real-world and synthetic datasets demonstrate that our method can identify influential nodes in dynamic networks accurately, at the same time, we also find some interesting phenomena and conclusions for those that have been validated in complex network or social science.

  2. Long term charge retention dynamics of SONOS cells

    Science.gov (United States)

    Arreghini, A.; Akil, N.; Driussi, F.; Esseni, D.; Selmi, L.; van Duuren, M. J.

    2008-09-01

    We present a model for charge retention dynamics in SONOS non volatile memory cells which accounts for the space and energy distributions of the trapped charge in the silicon nitride, self consistently with the potential. Long term retention measurements (beyond 106 s) versus temperature allowed us to decouple two charge loss mechanisms, to calibrate the model parameters and then to reproduce a large set of measurements on devices featuring different gate stacks, initial threshold voltages (including negative ones) and operation temperatures. A detailed analysis has been also carried out to compare the retention dynamics of cells featuring thin or thick tunnel oxide barriers.

  3. A long-term/short-term model for daily electricity prices with dynamic volatility

    Energy Technology Data Exchange (ETDEWEB)

    Schlueter, Stephan

    2010-09-15

    In this paper we introduce a new stochastic long-term/short-term model for short-term electricity prices, and apply it to four major European indices, namely to the German, Dutch, UK and Nordic one. We give evidence that all time series contain certain periodic (mostly annual) patterns, and show how to use the wavelet transform, a tool of multiresolution analysis, for filtering purpose. The wavelet transform is also applied to separate the long-term trend from the short-term oscillation in the seasonal-adjusted log-prices. In all time series we find evidence for dynamic volatility, which we incorporate by using a bivariate GARCH model with constant correlation. Eventually we fit various models from the existing literature to the data, and come to the conclusion that our approach performs best. For the error distribution, the Normal Inverse Gaussian distribution shows the best fit. (author)

  4. Characterizing and correcting for the effect of sensor noise in the dynamic mode decomposition

    CERN Document Server

    Dawson, Scott T M; Williams, Matthew O; Rowley, Clarence W

    2015-01-01

    Dynamic mode decomposition (DMD) provides a practical means of extracting insightful dynamical information from fluids datasets. Like any data processing technique, DMD's usefulness is limited by its ability to extract real and accurate dynamical features from noise-corrupted data. Here we show analytically that DMD is biased to sensor noise, and quantify how this bias depends on the size and noise level of the data. We present three modifications to DMD that can be used to remove this bias: (i) a direct correction of the identified bias using known noise properties, (ii) combining the results of performing DMD forwards and backwards in time, and (iii) a total least-squares-inspired algorithm. We discuss the relative merits of each algorithm, and demonstrate the performance of these modifications on a range of synthetic, numerical, and experimental datasets. We further compare our modified DMD algorithms with other variants proposed in recent literature.

  5. Direct Parametric Reconstruction With Joint Motion Estimation/Correction for Dynamic Brain PET Data.

    Science.gov (United States)

    Jiao, Jieqing; Bousse, Alexandre; Thielemans, Kris; Burgos, Ninon; Weston, Philip S J; Schott, Jonathan M; Atkinson, David; Arridge, Simon R; Hutton, Brian F; Markiewicz, Pawel; Ourselin, Sebastien

    2017-01-01

    Direct reconstruction of parametric images from raw photon counts has been shown to improve the quantitative analysis of dynamic positron emission tomography (PET) data. However it suffers from subject motion which is inevitable during the typical acquisition time of 1-2 hours. In this work we propose a framework to jointly estimate subject head motion and reconstruct the motion-corrected parametric images directly from raw PET data, so that the effects of distorted tissue-to-voxel mapping due to subject motion can be reduced in reconstructing the parametric images with motion-compensated attenuation correction and spatially aligned temporal PET data. The proposed approach is formulated within the maximum likelihood framework, and efficient solutions are derived for estimating subject motion and kinetic parameters from raw PET photon count data. Results from evaluations on simulated [(11)C]raclopride data using the Zubal brain phantom and real clinical [(18)F]florbetapir data of a patient with Alzheimer's disease show that the proposed joint direct parametric reconstruction motion correction approach can improve the accuracy of quantifying dynamic PET data with large subject motion.

  6. GA-based dynamical correction of dispersion coefficients in Lagrangian puff model

    Institute of Scientific and Technical Information of China (English)

    马元巍; 王德忠; 吉志龙

    2015-01-01

    In atmospheric dispersion models of nuclear accident, the dispersion coefficients were usually obtained by tracer experiment, which are constant in different atmospheric stability classifications. In fact, the atmospheric wind field is complex and unstable. The dispersion coefficients change even in the same atmospheric stability, hence the great errors brought in. According to the regulation, the air concentration of nuclides around nuclear power plant should be monitored during an accident. The monitoring data can be used to correct dispersion coefficients dynamically. The error can be minimized by correcting the coefficients. This reverse problem is nonlinear and sensitive to initial value. The property of searching the optimal solution of Genetic Algorithm (GA) is suitable for complex high-dimensional situation. In this paper, coupling with Lagrange dispersion model, GA is used to estimate the coefficients. The simulation results show that GA scheme performs well when the error is big. When the correcting process is used in the experiment data, the GA-estimated results are numerical instable. The success rate of estimation is 5%lower than the one without correction. Taking into account the continuity of the dispersion coefficient, Savitzky-Golay filter is used to smooth the estimated parameters. The success rate of estimation increases to 75.86%. This method can improve the accuracy of atmospheric dispersion simulation.

  7. A Novel Dynamic Bandwidth Allocation Algorithm with Correction-based the Multiple Traffic Prediction in EPON

    Directory of Open Access Journals (Sweden)

    Ziyi Fu

    2012-10-01

    Full Text Available According to the upstream TDM in the system of Ethernet passive optical network (EPON, this paper proposes a novel dynamic bandwidth allocation algorithm which supports the mechanism with correction-based the multiple services estimation. To improve the real-time performance of the bandwidth allocation, this algorithm forecasts the traffic of high priority services, and then pre-allocate bandwidth for various priority services is corrected according to Gaussian distribution characteristics, which will make traffic prediction closer to the real traffic. The simulation results show that proposed algorithm is better than the existing DBA algorithm. Not only can it meet the delay requirement of high priority services, but also control the delay abnormity of low priority services. In addition, with rectification scheme, it obviously improves the bandwidth utilization.

  8. Dynamic Black-Level Correction and Artifact Flagging for Kepler Pixel Time Series

    Science.gov (United States)

    Kolodziejczak, J. J.; Clarke, B. D.; Caldwell, D. A.

    2011-01-01

    Methods applied to the calibration stage of Kepler pipeline data processing [1] (CAL) do not currently use all of the information available to identify and correct several instrument-induced artifacts. These include time-varying crosstalk from the fine guidance sensor (FGS) clock signals, and manifestations of drifting moire pattern as locally correlated nonstationary noise, and rolling bands in the images which find their way into the time series [2], [3]. As the Kepler Mission continues to improve the fidelity of its science data products, we are evaluating the benefits of adding pipeline steps to more completely model and dynamically correct the FGS crosstalk, then use the residuals from these model fits to detect and flag spatial regions and time intervals of strong time-varying black-level which may complicate later processing or lead to misinterpretation of instrument behavior as stellar activity.

  9. Dynamic graded subtraction: a simple method to background correct and display multicompartmental radiopharmaceutical scintigrams

    Energy Technology Data Exchange (ETDEWEB)

    Tuscan, M.J.; Wahl, R.L.; Botti, J.

    1985-09-01

    A common procedure to enhance the localization of a poorly localized radiopharmaceutical is to mimic and subtract its undesirable component with a second radionuclide of a different photopeak that is physiologic nonspecific. Determination of the exact amount of the nonspecific radionuclide to subtract in a single step, however, is difficult. The authors describe the use of a simple method to enhance an image of a poorly localized radiopharmaceutical by incrementally subtracting another image of a specific radiopharmaceutical that mimics the objectionable image data and displays the corrected image series in cinematic mode. This method of image correction and dynamic display may be useful for a variety of procedures in which there is a significant nonspecific component of the radiotracer such as in radiolabeled antibodies, or to perform selective compartmental or organ subtraction in the case of a mixed specificity radiopharmaceutical.

  10. Classifying genes to the correct Gene Ontology Slim term in Saccharomyces cerevisiae using neighbouring genes with classification learning

    Directory of Open Access Journals (Sweden)

    Tsatsoulis Costas

    2010-05-01

    Full Text Available Abstract Background There is increasing evidence that gene location and surrounding genes influence the functionality of genes in the eukaryotic genome. Knowing the Gene Ontology Slim terms associated with a gene gives us insight into a gene's functionality by informing us how its gene product behaves in a cellular context using three different ontologies: molecular function, biological process, and cellular component. In this study, we analyzed if we could classify a gene in Saccharomyces cerevisiae to its correct Gene Ontology Slim term using information about its location in the genome and information from its nearest-neighbouring genes using classification learning. Results We performed experiments to establish that the MultiBoostAB algorithm using the J48 classifier could correctly classify Gene Ontology Slim terms of a gene given information regarding the gene's location and information from its nearest-neighbouring genes for training. Different neighbourhood sizes were examined to determine how many nearest neighbours should be included around each gene to provide better classification rules. Our results show that by just incorporating neighbour information from each gene's two-nearest neighbours, the percentage of correctly classified genes to their correct Gene Ontology Slim term for each ontology reaches over 80% with high accuracy (reflected in F-measures over 0.80 of the classification rules produced. Conclusions We confirmed that in classifying genes to their correct Gene Ontology Slim term, the inclusion of neighbour information from those genes is beneficial. Knowing the location of a gene and the Gene Ontology Slim information from neighbouring genes gives us insight into that gene's functionality. This benefit is seen by just including information from a gene's two-nearest neighbouring genes.

  11. Classifying genes to the correct Gene Ontology Slim term in Saccharomyces cerevisiae using neighbouring genes with classification learning.

    Science.gov (United States)

    Amthauer, Heather A; Tsatsoulis, Costas

    2010-05-28

    There is increasing evidence that gene location and surrounding genes influence the functionality of genes in the eukaryotic genome. Knowing the Gene Ontology Slim terms associated with a gene gives us insight into a gene's functionality by informing us how its gene product behaves in a cellular context using three different ontologies: molecular function, biological process, and cellular component. In this study, we analyzed if we could classify a gene in Saccharomyces cerevisiae to its correct Gene Ontology Slim term using information about its location in the genome and information from its nearest-neighbouring genes using classification learning. We performed experiments to establish that the MultiBoostAB algorithm using the J48 classifier could correctly classify Gene Ontology Slim terms of a gene given information regarding the gene's location and information from its nearest-neighbouring genes for training. Different neighbourhood sizes were examined to determine how many nearest neighbours should be included around each gene to provide better classification rules. Our results show that by just incorporating neighbour information from each gene's two-nearest neighbours, the percentage of correctly classified genes to their correct Gene Ontology Slim term for each ontology reaches over 80% with high accuracy (reflected in F-measures over 0.80) of the classification rules produced. We confirmed that in classifying genes to their correct Gene Ontology Slim term, the inclusion of neighbour information from those genes is beneficial. Knowing the location of a gene and the Gene Ontology Slim information from neighbouring genes gives us insight into that gene's functionality. This benefit is seen by just including information from a gene's two-nearest neighbouring genes.

  12. A Long-Term Wind Speed Ensemble Forecasting System with Weather Adapted Correction

    Directory of Open Access Journals (Sweden)

    Yiqi Chu

    2016-10-01

    Full Text Available Wind forecasting is critical in the wind power industry, yet forecasting errors often exist. In order to effectively correct the forecasting error, this study develops a weather adapted bias correction scheme on the basis of an average bias-correction method, which considers the deviation of estimated biases associated with the difference in weather type within each unit of the statistical sample. This method is tested by an ensemble forecasting system based on the Weather Research and Forecasting (WRF model. This system provides high resolution wind speed deterministic forecasts using 40 members generated by initial perturbations and multi-physical schemes. The forecasting system outputs 28–52 h predictions with a temporal resolution of 15 min, and is evaluated against collocated anemometer towers observations at six wind fields located on the east coast of China. Results show that the information contained in weather types produces an improvement in the forecast bias correction.

  13. Can dispersion corrections annihilate the dispersion-driven nano-aggregation of non-polar groups? An ab initio molecular dynamics study of ionic liquid systems.

    Science.gov (United States)

    Firaha, Dzmitry S; Thomas, Martin; Hollóczki, Oldamur; Korth, Martin; Kirchner, Barbara

    2016-11-28

    In this study, we aim at understanding the influence of dispersion correction on the ab initio molecular dynamics simulations of ionic liquid (IL) systems. We investigated a large bulk system of the 1-butyl-3-methylimidazolium triflate IL and a small cluster system of ethylamine in ethylammonium nitrate both under periodic boundary conditions. The large system displays several changes upon neglect of dispersion correction, the most striking one is the surprising decrease of the well-known microheterogeneity which is accompanied by an increase of side chain hydrogen atom-anion interplay. For the diffusion coefficient, we observe a correction towards experimental behavior in terms of the cation becoming faster than the anion with dispersion correction. Changes in the electronic structure upon dispersion correction are reflected in larger/smaller dipole moments for anions/cations also seen in the calculated IR spectrum. The energetics of different ion pair dimer subsystems (polar and non-polar) are in accordance with the analysis of the trajectories: A detailed balance in the ionic liquid system determines its particular behavior. While the overall interaction terms for dispersion-corrected calculations are higher, the decrease in microheterogeneity upon inclusion of dispersion interaction becomes obvious due to the relation between all contributions to polar-polar terms. For the small system, we clearly observe the well known behavior that the hybrid functionals show higher reaction barriers than the pure generalized gradient approximation (GGA) functionals. The correction of dispersion reduces the discrepancies in some cases. Accounting for the number of jumps, we observe that dispersion correction reduces the discrepancies from 50% to less than 10%.

  14. Can dispersion corrections annihilate the dispersion-driven nano-aggregation of non-polar groups? An ab initio molecular dynamics study of ionic liquid systems

    Science.gov (United States)

    Firaha, Dzmitry S.; Thomas, Martin; Hollóczki, Oldamur; Korth, Martin; Kirchner, Barbara

    2016-11-01

    In this study, we aim at understanding the influence of dispersion correction on the ab initio molecular dynamics simulations of ionic liquid (IL) systems. We investigated a large bulk system of the 1-butyl-3-methylimidazolium triflate IL and a small cluster system of ethylamine in ethylammonium nitrate both under periodic boundary conditions. The large system displays several changes upon neglect of dispersion correction, the most striking one is the surprising decrease of the well-known microheterogeneity which is accompanied by an increase of side chain hydrogen atom-anion interplay. For the diffusion coefficient, we observe a correction towards experimental behavior in terms of the cation becoming faster than the anion with dispersion correction. Changes in the electronic structure upon dispersion correction are reflected in larger/smaller dipole moments for anions/cations also seen in the calculated IR spectrum. The energetics of different ion pair dimer subsystems (polar and non-polar) are in accordance with the analysis of the trajectories: A detailed balance in the ionic liquid system determines its particular behavior. While the overall interaction terms for dispersion-corrected calculations are higher, the decrease in microheterogeneity upon inclusion of dispersion interaction becomes obvious due to the relation between all contributions to polar-polar terms. For the small system, we clearly observe the well known behavior that the hybrid functionals show higher reaction barriers than the pure generalized gradient approximation (GGA) functionals. The correction of dispersion reduces the discrepancies in some cases. Accounting for the number of jumps, we observe that dispersion correction reduces the discrepancies from 50% to less than 10%.

  15. Modeling and estimating change in temporal networks via a dynamic degree corrected stochastic block model

    CERN Document Server

    Wilson, James D; Woodall, William H

    2016-01-01

    In many applications it is of interest to identify anomalous behavior within a dynamic interacting system. Such anomalous interactions are reflected by structural changes in the network representation of the system. We propose and investigate the use of a dynamic version of the degree corrected stochastic block model (DCSBM) as a means to model and monitor dynamic networks that undergo a significant structural change. Our model provides a means to simulate a variety of local and global changes in a time-varying network. Furthermore, one can efficiently detect such changes using the maximum likelihood estimates of the parameters that characterize the DCSBM. We assess the utility of the dynamic DCSBM on both simulated and real networks. Using a simple monitoring strategy on the DCSBM, we are able to detect significant changes in the U.S. Senate co-voting network that reflects both times of cohesion and times of polarization among Republican and Democratic members. Our analysis suggests that the dynamic DCSBM pr...

  16. On-line Dynamic Model Correction Based Fault Diagnosis in Chemical Processes

    Institute of Scientific and Technical Information of China (English)

    田文德; 孙素莉

    2007-01-01

    A novel fault detection and diagnosis method was proposed,using dynamic simulation to monitor chemical process and identify faults when large tracking deviations occur.It aims at parameter failures,and the parameters are updated via on-line correction.As it can predict the trend of process and determine the existence of malfunctions simultaneously,this method does not need to design problem-specific observer to estimate unmeasured state variables.Application of the proposed method is presented on one water tank and one aromatization reactor,and the results are compared with those from the traditional method.

  17. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics

    Science.gov (United States)

    Dong, Bing; Li, Yan; Han, Xin-li; Hu, Bin

    2016-01-01

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10−5 in optimized correction and is 1.427 × 10−5 in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method. PMID:27598161

  18. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics.

    Science.gov (United States)

    Dong, Bing; Li, Yan; Han, Xin-Li; Hu, Bin

    2016-09-02

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10(-5) in optimized correction and is 1.427 × 10(-5) in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method.

  19. Study on the influence of stochastic properties of correction terms on the reliability of instantaneous network RTK

    Science.gov (United States)

    Próchniewicz, Dominik

    2014-03-01

    The reliability of precision GNSS positioning primarily depends on correct carrier-phase ambiguity resolution. An optimal estimation and correct validation of ambiguities necessitates a proper definition of mathematical positioning model. Of particular importance in the model definition is the taking into account of the atmospheric errors (ionospheric and tropospheric refraction) as well as orbital errors. The use of the network of reference stations in kinematic positioning, known as Network-based Real-Time Kinematic (Network RTK) solution, facilitates the modeling of such errors and their incorporation, in the form of correction terms, into the functional description of positioning model. Lowered accuracy of corrections, especially during atmospheric disturbances, results in the occurrence of unaccounted biases, the so-called residual errors. The taking into account of such errors in Network RTK positioning model is possible by incorporating the accuracy characteristics of the correction terms into the stochastic model of observations. In this paper we investigate the impact of the expansion of the stochastic model to include correction term variances on the reliability of the model solution. In particular the results of instantaneous solution that only utilizes a single epoch of GPS observations, is analyzed. Such a solution mode due to the low number of degrees of freedom is very sensitive to an inappropriate mathematical model definition. Thus the high level of the solution reliability is very difficult to achieve. Numerical tests performed for a test network located in mountain area during ionospheric disturbances allows to verify the described method for the poor measurement conditions. The results of the ambiguity resolution as well as the rover positioning accuracy shows that the proposed method of stochastic modeling can increase the reliability of instantaneous Network RTK performance.

  20. Molecular dynamics of large systems with quantum corrections for the nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Bing; Garashchuk, Sophya, E-mail: garashchuk@sc.edu [Department of Chemistry & Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

    2015-12-31

    This paper describes an approximate approach to quantum dynamics based on the quantum trajectory formulation of the Schrödinger equation. The quantum-mechanical effects are incorporated through the quantum potential of the mean-field type, acting on a trajectory ensemble in addition to the classical potential. Efficiency for large systems is achieved by using the quantum corrections for selected degrees of freedom and introduction of empirical friction into the ground-state energy calculations. The classical potential, if needed, can be computed on-the-fly using the Density Functional Tight Binding method of electronic structure merged with the quantum trajectory dynamics code. The approach is practical for a few hundred atoms. Applications include a study of adsorption of quantum hydrogen colliding with the graphene model, C{sub 37}H{sub 15} and a calculation of the ground state of solid {sup 4}He simulated by a cell 180-atoms.

  1. Quantum corrected Langevin dynamics for adsorbates on metal surfaces interacting with hot electrons

    DEFF Research Database (Denmark)

    Olsen, Thomas; Schiøtz, Jakob

    2010-01-01

    quantum mechanical probabilities from the classical phase space distributions resulting from the dynamics. At short time scales, classical and quasiclassical initial conditions lead to wrong results and only correctly quantized initial conditions give a close agreement with an inherently quantum......We investigate the importance of including quantized initial conditions in Langevin dynamics for adsorbates interacting with a thermal reservoir of electrons. For quadratic potentials the time evolution is exactly described by a classical Langevin equation and it is shown how to rigorously obtain...... mechanical master equation approach. With CO on Cu(100) as an example, we demonstrate the effect for a system with ab initio frictional tensor and potential energy surfaces and show that quantizing the initial conditions can have a large impact on both the desorption probability and the distribution...

  2. Habitable Planets: Interior Dynamics and Long-Term Evolution

    Science.gov (United States)

    Tackley, Paul J.; Ammann, Michael M.; Brodholt, John P.; Dobson, David P.; Valencia, Diana

    2014-04-01

    Here, the state of our knowledge regarding the interior dynamics and evolution of habitable terrestrial planets including Earth and super-Earths is reviewed, and illustrated using state-of-the-art numerical models. Convection of the rocky mantle is the key process that drives the evolution of the interior: it causes plate tectonics, controls heat loss from the metallic core (which generates the magnetic field) and drives long-term volatile cycling between the atmosphere/ocean and interior. Geoscientists have been studying the dynamics and evolution of Earth's interior since the discovery of plate tectonics in the late 1960s and on many topics our understanding is very good, yet many first-order questions remain. It is commonly thought that plate tectonics is necessary for planetary habitability because of its role in long-term volatile cycles that regulate the surface environment. Plate tectonics is the surface manifestation of convection in the 2900-km deep rocky mantle, yet exactly how plate tectonics arises is still quite uncertain; other terrestrial planets like Venus and Mars instead have a stagnant lithosphere- essentially a single plate covering the entire planet. Nevertheless, simple scalings as well as more complex models indicate that plate tectonics should be easier on larger planets (super-Earths), other things being equal. The dynamics of terrestrial planets, both their surface tectonics and deep mantle dynamics, change over billions of years as a planet cools. Partial melting is a key process influencing solid planet evolution. Due to the very high pressure inside super-Earths' mantles the viscosity would normally be expected to be very high, as is also indicated by our density function theory (DFT) calculations. Feedback between internal heating, temperature and viscosity leads to a superadiabatic temperature profile and self-regulation of the mantle viscosity such that sluggish convection still occurs.

  3. Correct block artifacts by differential projection for a dynamic computed tomography system

    Science.gov (United States)

    Xiao, Yongshun; Han, Fangda; Chen, Zhiqiang

    2017-09-01

    In the aero-engine industry, it is important to carry out regular and effective tests on engines in service. However, current detection methods often have problems such as a limitation on materials characteristics or geometry structures. Recently, a novel dynamic computed tomography (CT) system was proposed to provide highly efficient CT inspection for rotating parts, in particular the blades of aero-engines in operation. However, one problem exists in the proposed system in that some components remain static when the engine is in operation. These static parts will appear as strip artifacts in projection and ultimately as ring artifacts in the reconstructed image, which are called block artifacts. In this paper, we put forward a differential projection correction method to correct block artifacts and reconstruct the blades of the aero-engine. The method makes use of the distribution of the blades and the static parts to remove the artifacts. The experiment results show that the proposed method can effectively remove the block artifacts while maintaining the grayscale and geometry structure of the blades, furthermore, we also verify its ability to detect defects using numerical experiments. The differential projection correction method makes the system more practicable for in situ inspection of aero-engines.

  4. A Dynamical Resolution of the Sigma Term Puzzle

    CERN Document Server

    Ball, R D; Tigg, J; Ball, Richard D.; Forte, Stefano; Tigg, Jason

    1994-01-01

    We propose a resolution of the puzzle posed by the discrepancy between the pion-nucleon sigma term inferred from pion-nucleon scattering, and that deduced from baryon mass splittings using the Zweig rule. We show that there is a significant hypercharge-dependent dynamical contribution to baryon masses, not hitherto included in the analysis, which may be estimated using the scale Ward identity, and computed by solution of the Schwinger-Dyson equation for the quark self-energy. We find that the discrepancy is completely resolved without the need for any Zweig rule violation.

  5. Long-term dynamics of high mass ratio multiples

    Science.gov (United States)

    Li, Gongjie

    This thesis presents a series of studies on the dynamics of high mass ratio multiples, with applications to planetary systems orbiting stars and stellar systems orbiting supermassive black holes (SMBHs). Almost two thousand exoplanetary systems have recently been discovered, and their configurations gave rise to new puzzles to planetary formation theories. We studied the dynamics of planetary systems aiming to understand how the configuration of planetary system is sculptured and to probe the origin of planetary systems. First, we discussed hierarchical three-body dynamics, which can be applied to planets that are orbiting a star while perturbed by a planet or a star that is farther away. The perturbation from the farther object can flip the planetary orbits and produce counter orbiting hot Jupiters, which cannot be formed in the classical planetary formation theory. In addition, we have studied the scatter encounter of planetary systems in clusters, which produce eccentric and inclined planets. Moreover, we investigated the obliquity variation of planets, which can be applied to exoplanetary systems. The obliquity variation is important to the habitability of the exoplanets. The long term dynamics is also important to stellar systems orbiting SMBHs. SMBHs are common in the center of galaxies and lead to rich dynamical interactions with nearby stars. At the same time, dynamical features of the nearby stars reveal important properties of the SMBHs. The aforementioned hierarchical three-body dynamics can be applied to stars near SMBH binaries, which are natural consequences of galaxy mergers. We found that the distribution of stars surrounding one of the SMBHs results in a shape of torus due to the perturbation from the other SMBH, and the dynamical interactions contribute to an enhancement of tidal disruption rates, which can help identify the SMBH binaries. In addition, we investigated the heating of stars near SMBHs, where the heating of stars due to gravitational

  6. The dynamics of accounting terms in a globalized environment

    DEFF Research Database (Denmark)

    Fuertes-Olivera, Pedro A.; Nielsen, Sandro

    2014-01-01

    European accounting terminology is dynamic as term creation occurs on national, European Union and international levels. English is the lingua franca of accounting, which influences terminologies in other languages, usually through the work of translators, e.g. the translation of existing...... international accounting standards. The combined influence of these forces is discussed in this chapter that explains the existence of a globalized trend towards a kind of cultural uniformity. This manifests itself in many ways, two of which are: the translation of English multiword accounting terms...... into Spanish; and the presence of novel metaphors in Spanish accounting. The data used in the discussion are taken from the accounting dictionaries, a collection of online dictionaries in three languages: Danish, English and Spanish....

  7. Analytic corrections to AdS by scalar matter and curvature squared term

    CERN Document Server

    Joshi, Lata Kh

    2016-01-01

    We revisit the background solution for scalar matter coupled higher derivative gravity originally reported in arXiv: 1409.8019[hep-th]. In this letter, we choose a convenient ansatz for metric which determines the first order perturbative corrections to scalar as well as geometry.

  8. QCD in terms of gauge-invariant dynamical variables

    CERN Document Server

    Pavel, Hans-Peter

    2013-01-01

    For a complete description of the physical properties of low-energy QCD, it might be advantageous to first reformulate QCD in terms of gauge-invariant dynamical variables, before applying any approximation schemes. Using a canonical transformation of the dynamical variables, which Abelianises the non-Abelian Gauss-law constraints to be implemented, such a reformulation can be achieved for QCD. The exact implementation of the Gauss laws reduces the colored spin-1 gluons and spin-1/2 quarks to unconstrained colorless spin-0, spin-1, spin-2 and spin-3 glueball fields and colorless Rarita-Schwinger fields respectively. The obtained physical Hamiltonian can then be rewritten into a form, which separates the rotational from the scalar degrees of freedom, and admits a systematic strong-coupling expansion in powers of lambda=g^{-2/3}, equivalent to an expansion in the number of spatial derivatives. The leading-order term in this expansion corresponds to non-interacting hybrid-glueballs, whose low-lying masses can be ...

  9. Distinguishing the Noise and image structures for detecting the correction term and filtering the noise by using fuzzy rules

    Directory of Open Access Journals (Sweden)

    Sridevi.Ravada,

    2011-07-01

    Full Text Available A fuzzy filter is constructed from a set of fuzzy IF-THEN rules, these fuzzy rules come either from human experts or by matching input-output pairs .in this paper we propose a new fuzzy filter for the noise reduction of images corrupted with additive noise. here in this approach ,initially fuzzy derivatives for all eight directions that is N,E,W,S, NE,NW,SE,SW are calculated using “fuzzy IF-THEN rules “ and membership functions . Further the fuzzy derivative values obtained are used in the fuzzy smoothing for determining the correction term. Finally correction term can be added to the processed pixel value. Iteratively apply the fuzzy filter to reduce the noise and at each and every iteration membership function iscalculated based on the remaining noise level. A statistical model for the noise distribution can be incorporated to relate the homogeneity to the adaptation scheme of the membership functions.

  10. [Physiotherapy in correction of proatherogenic shifts in long-term administration of beta-blockers and thiazide diuretics].

    Science.gov (United States)

    Razumov, A N; Kniazeva, T A; Badtieva, V A

    2002-01-01

    A physiotherapeutic complex (laser therapy, dry carbon dioxide and iodine-bromine baths) addition to a course treatment with beta-blockers and thiazide diuretics produced positive changes in the levels of triglicerides, total cholesterol, beta- and alpha-cholesterol, lipid peroxidation in patients with proatherogenic shifts in the lipid spectrum and lipid peroxidation system secondary to long-term therapy with beta-blockers and thiazide diuretics, and therefore can be used for partial correction and prevention of the above shifts.

  11. Medium-term dynamics of a middle Adriatic barred beach

    Directory of Open Access Journals (Sweden)

    M. Postacchini

    2017-09-01

    Full Text Available In recent years, attention has been paid to beach protection by means of soft and hard defenses. Along the Italian coast of the Adriatic Sea, sandy beaches are the most common landscape feature and around 70 % of the Marche region's coast (central Adriatic is protected by defense structures. The longest free-from-obstacle nearshore area in the region includes the beach of Senigallia, frequently monitored in the last decades and characterized by a multiple bar system, which represents a natural beach defense. The bathymetries surveyed in 2006, 2010, 2011, 2012 and 2013 show long-term stability, confirmed by a good adaptation of an analyzed stretch of the beach to the Dean-type equilibrium profile, though a strong short- to medium-term variability of the wave climate has been observed during the monitored periods. The medium-term dynamics of the beach, which deal with the evolution of submerged bars and are of the order of years or seasons, have been related to the wave climate collected, during the analyzed temporal windows, by a wave buoy located about 40 km off Senigallia. An overall interpretation of the hydrodynamics, sediment characteristics and seabed morphology suggests that the wave climate is fundamental for the morphodynamic changes of the beach in the medium term. These medium-term time ranges during which waves mainly come from NNE/ESE are characterized by a larger/smaller steepness and by a larger/smaller relative wave height, and seem to induce seaward/shoreward bar migration as well as bar smoothing/steepening. Moving southeastward, the bar dimension increases, while the equilibrium profile shape suggests the adaptation to a decreasing sediment size in the submerged beach. This is probably due to the presence of both the harbor jetty and river mouth north of the investigated area.

  12. First-order correction terms in the weak-field asymptotic theory of tunneling ionization in many-electron systems

    Science.gov (United States)

    Trinh, Vinh H.; Tolstikhin, Oleg I.; Morishita, Toru

    2016-10-01

    The many-electron weak-field asymptotic theory of tunneling ionization including the first-order correction terms in the asymptotic expansion of the ionization rate in field strength was highlighted in our recent fast track communication (Trinh et al 2015 J. Phys. B: At. Mol. Opt. Phys. 48 061003) by demonstrating its performance for two-electron atoms. Here we present a thorough derivation of the first-order terms omitted in the previous publication and provide additional numerical illustrations of the theory.

  13. Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

    Science.gov (United States)

    Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

    2007-01-01

    The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

  14. Benign anatomical mistakes: the correct anatomical term for the recurrent laryngeal nerve.

    Science.gov (United States)

    Mirilas, Petros; Skandalakis, John E

    2002-01-01

    The term recurrent laryngeal nerve has been adopted by Nomina Anatomica (1989) and Terminologia Anatomica (1998) to describe this vagus branch from its origin, its turn dorsally around the subclavian artery and the aortic arch, and its cranial pathway until it reaches its terminal organs in the neck. However, there is still much confusion, and either the terms inferior and recurrent laryngeal nerve are used interchangeably or inferior laryngeal nerve is considered the terminal branch of the recurrent laryngeal nerve. We hereby feel that it is necessary to reassess the term and we propose the term inferior laryngeal nerve for the entire nerve under consideration, from its origin from the vagus nerve to its destinations, including tracheal, esophageal, and pharyngeal branches. If the term superior laryngeal nerve is a given, standard and accepted term in the anatomical terminology, then logically the term inferior laryngeal nerve should also be accepted, as opposed to it. Of course the upward travel of the inferior laryngeal nerve is "recurrent". When nonrecurrence is encountered together with an arteria lusoria, a retroesophageal right subclavian artery or a right aortic arch, we consider that the term nonrecurrent inferior laryngeal nerve should be used to describe the deviation from the normal.

  15. Laboratory comparison of coronagraphic concepts under dynamical seeing and high-order adaptive optics correction

    CERN Document Server

    Martinez, P; Kasper, M; Boccaletti, A; Dorrer, C; Baudrand, J

    2011-01-01

    The exoplanetary science through direct imaging and spectroscopy will largely expand with the forthcoming development of new instruments at the VLT (SPHERE), Gemini (GPI), Subaru (HiCIAO), and Palomar (Project 1640) observatories. All these ground-based adaptive optics instruments combine extremely high performance adaptive optics (XAO) systems correcting for the atmospheric turbulence with advanced starlight-cancellation techniques such as coronagraphy to deliver contrast ratios of about 10-6 to 10-7. While the past fifteen years have seen intensive research and the development of high-contrast coronagraph concepts, very few concepts have been tested under dynamical seeing conditions (either during sky observation or in a realistic laboratory environment). In this paper, we discuss the results obtained with four different coronagraphs -- phase and amplitude types -- on the High-Order Testbench (HOT), the adaptive optics facility developed at ESO. This facility emphasizes realistic conditions encountered at a...

  16. Scatter correction in planar imaging and SPECT by constrained factor analysis of dynamic structures (FADS)

    Energy Technology Data Exchange (ETDEWEB)

    Mas, J.; Younes, R.B.; Bellaton, B.; Bidet, R. (Centre Hospitalier Universitaire Jean Minjoz, 25 - Besancon (France). Lab. de Biophysique et de Medecine Nucleaire); Hannequin, P. (Centre d' Imagerie Nucleaire, 74 -Annecy (France))

    1990-11-01

    A new approach to Compton scatter correction based on factor analysis of dynamic structures (FADS) is presented in this study. The innovation is the use of a constrained photopeak factor. This novel algorithm is evaluated both on planar imaging and SPECT data using Monte Carlo simulations and real phantoms. A comparison with the modified method of Jaszczak is also presented. Different parameters are significantly improved with the authors' recombination method in SPECT studies; particularly after attenuation compensation by the iterative method of Chang. Compared with the subtraction method the contrast is increased by 1.5 for planar Monte Carlo simulations and the scatter fraction is reduced four times with the recombination method. (author).

  17. Faster dynamic imaging of speech with field inhomogeneity corrected spiral fast low angle shot (FLASH) at 3 T.

    Science.gov (United States)

    Sutton, Bradley P; Conway, Charles A; Bae, Youkyung; Seethamraju, Ravi; Kuehn, David P

    2010-11-01

    To evaluate the impact of magnetic field inhomogeneity correction on achievable imaging speeds for magnetic resonance imaging (MRI) of articulating oropharyngeal structures during speech and to determine if sufficient acquisition speed is available for visualizing speech structures with real-time MRI. We designed a spiral fast low angle shot (FLASH) sequence that combines several acquisition techniques with an advanced image reconstruction approach that includes magnetic field inhomogeneity correction. A simulation study was performed to examine the interaction between imaging speed, image quality, number of spiral shots, and field inhomogeneity correction. Six volunteer subjects were scanned to demonstrate adequate visualization of articulating structures during simple speech samples. The simulation study confirmed that magnetic field inhomogeneity correction improves the available tradeoff between image quality and speed. Our optimized sequence co-acquires magnetic field maps for image correction and achieves a dynamic imaging rate of 21.4 frames per second, significantly faster than previous studies. Improved visualization of anatomical structures, such as the soft palate, was also seen from the field-corrected reconstructions in data acquired on volunteer subjects producing simple speech samples. Adequate temporal resolution of articulating oropharyngeal structures during speech can be obtained by combining outer volume suppression, multishot spiral imaging, and magnetic field corrected image reconstruction. Correcting for the large, dynamic magnetic field variation in the oropharyngeal cavity improves image quality and allows for higher temporal resolution. © 2010 Wiley-Liss, Inc.

  18. Analysis and Correction of Dynamic Geometric Misalignment for Nano-Scale Computed Tomography at BSRF.

    Directory of Open Access Journals (Sweden)

    Jian Fu

    Full Text Available Due to its high spatial resolution, synchrotron radiation x-ray nano-scale computed tomography (nano-CT is sensitive to misalignments in scanning geometry, which occurs quite frequently because of mechanical errors in manufacturing and assembly or from thermal expansion during the time-consuming scanning. Misalignments degrade the imaging results by imposing artifacts on the nano-CT slices. In this paper, the geometric misalignment of the synchrotron radiation nano-CT has been analyzed by partial derivatives on the CT reconstruction algorithm and a correction method, based on cross correlation and least-square sinusoidal fitting, has been reported. This work comprises a numerical study of the method and its experimental verification using a dataset measured with the full-field transmission x-ray microscope nano-CT at the beamline 4W1A of the Beijing Synchrotron Radiation Facility. The numerical and experimental results have demonstrated the validity of the proposed approach. It can be applied for dynamic geometric misalignment and needs neither phantom nor additional correction scanning. We expect that this method will simplify the experimental operation of synchrotron radiation nano-CT.

  19. Dynamic Black-Level Correction and Artifact Flagging in the Kepler Data Pipeline

    Science.gov (United States)

    Clarke, B. D.; Kolodziejczak, J. J.; Caldwell, D. A.

    2013-01-01

    Instrument-induced artifacts in the raw Kepler pixel data include time-varying crosstalk from the fine guidance sensor (FGS) clock signals, manifestations of drifting moiré pattern as locally correlated nonstationary noise and rolling bands in the images which find their way into the calibrated pixel time series and ultimately into the calibrated target flux time series. Using a combination of raw science pixel data, full frame images, reverse-clocked pixel data and ancillary temperature data the Keplerpipeline models and removes the FGS crosstalk artifacts by dynamically adjusting the black level correction. By examining the residuals to the model fits, the pipeline detects and flags spatial regions and time intervals of strong time-varying blacklevel (rolling bands ) on a per row per cadence basis. These flags are made available to downstream users of the data since the uncorrected rolling band artifacts could complicate processing or lead to misinterpretation of instrument behavior as stellar. This model fitting and artifact flagging is performed within the new stand-alone pipeline model called Dynablack. We discuss the implementation of Dynablack in the Kepler data pipeline and present results regarding the improvement in calibrated pixels and the expected improvement in cotrending performances as a result of including FGS corrections in the calibration. We also discuss the effectiveness of the rolling band flagging for downstream users and illustrate with some affected light curves.

  20. Efficient dynamical correction of the transition state theory rate estimate for a flat energy barrier

    CERN Document Server

    Mökkönen, Harri; Jónsson, Hannes

    2016-01-01

    The recrossing correction to the transition state theory estimate of a thermal rate can be difficult to calculate when the energy barrier is flat. This problem arises, for example, in polymer escape if the polymer is long enough to stretch between the initial and final state energy wells while the polymer beads undergo diffusive motion back and forth over the barrier. We present an efficient method for evaluating the correction factor by constructing a sequence of hyperplanes starting at the transition state and calculating the probability that the system advances from one hyperplane to another towards the product. This is analogous to what is done in forward flux sampling except that there the hyperplane sequence starts at the initial state. The method is applied to the escape of polymers with up to 64 beads from a potential well. For high temperature, the results are compared with direct Langevin dynamics simulations as well as forward flux sampling and excellent agreement between the three rate estimates i...

  1. Color correction for high dynamic range images using a chromatic adaptation method

    Science.gov (United States)

    Yun, Byoung-Ju; Park, Jinhyung; Kim, Seunghae; Kim, Hyun-Deok; Choi, Ho-Hyoung

    2013-01-01

    In the image capturing process using a camera, poor illumination has an influence on the image quality, especially in regards to the contrast and details in the dark regions. Generally, high dynamic range (HDR) imaging techniques are used to match the quality between the real scene and the displayed image. However, in images using the multi-exposure technique or regular photography, the images are limited by the veiling glare, which is scene-, exposure-, lens-, aperture-, and camera-dependent. This study mainly addressed images using the multi-exposure technique and developed a color correction scheme that uses a chromatic adaptation method. In the tone mapping using a Gaussian pyramid, the adaptation level is obtained based on a linear Gaussian filter. The resulting image is then processed through the developed tone-mapping function. This allows the chromatic adaptation method to address the mismatches between the real world and the displayed image. The experiment results show that the proposed method yields a better color correction performance compared to conventional methods.

  2. Arrival time correction for dynamic susceptibility contrast MR permeability imaging in stroke patients.

    Directory of Open Access Journals (Sweden)

    Richard Leigh

    Full Text Available PURPOSE: To determine if applying an arrival time correction (ATC to dynamic susceptibility contrast (DSC based permeability imaging will improve its ability to identify contrast leakage in stroke patients for whom the shape of the measured curve may be very different due to hypoperfusion. MATERIALS AND METHODS: A technique described in brain tumor patients was adapted to incorporate a correction for delayed contrast delivery due to perfusion deficits. This technique was applied to the MRIs of 9 stroke patients known to have blood-brain barrier (BBB disruption on T1 post contrast imaging. Regions of BBB damage were compared with normal tissue from the contralateral hemisphere. Receiver operating characteristic (ROC analysis was performed to compare the detection of BBB damage before and after ATC. RESULTS: ATC improved the area under the curve (AUC of the ROC from 0.53 to 0.70. The sensitivity improved from 0.51 to 0.67 and the specificity improved from 0.57 to 0.66. Visual inspection of the ROC curve revealed that the performance of the uncorrected analysis was worse than random guess at some thresholds. CONCLUSIONS: The ability of DSC permeability imaging to identify contrast enhancing tissue in stroke patients improved considerably when an ATC was applied. Using DSC permeability imaging in stroke patients without an ATC may lead to false identification of BBB disruption.

  3. Average hydrodynamic correction for the Brownian dynamics calculation of flocculation rates in concentrated dispersions

    Science.gov (United States)

    Urbina-Villalba, German; García-Sucre, Máximo; Toro-Mendoza, Jhoan

    2003-12-01

    In order to account for the hydrodynamic interaction (HI) between suspended particles in an average way, Honig et al. [J. Colloid Interface Sci. 36, 97 (1971)] and more recently Heyes [Mol. Phys. 87, 287 (1996)] proposed different analytical forms for the diffusion constant. While the formalism of Honig et al. strictly applies to a binary collision, the one from Heyes accounts for the dependence of the diffusion constant on the local concentration of particles. However, the analytical expression of the latter approach is more complex and depends on the particular characteristics of each system. Here we report a combined methodology, which incorporates the formula of Honig et al. at very short distances and a simple local volume-fraction correction at longer separations. As will be shown, the flocculation behavior calculated from Brownian dynamics simulations employing the present technique, is found to be similar to that of Batchelor’s tensor [J. Fluid. Mech. 74, 1 (1976); 119, 379 (1982)]. However, it corrects the anomalous coalescence found in concentrated systems as a result of the overestimation of many-body HI.

  4. First-order correction terms in the weak-field asymptotic theory of tunneling ionization

    DEFF Research Database (Denmark)

    Trinh, Vinh H.; Tolstikhin, Oleg I.; Madsen, Lars Bojer

    2013-01-01

    The weak-field asymptotic theory (WFAT) of tunneling ionization in a static electric field is developed to the next order in field. The first-order corrections to the ionization rate and transverse momentum distribution of the ionized electrons are derived. This extends the region of applicability...... of the WFAT at the quantitative level toward stronger fields, practically up to the boundary between tunneling and over-the-barrier regimes of ionization. The results apply to any atom or molecule treated in the single-active-electron and frozen-nuclei approximations. The theory is illustrated by calculations...... for hydrogen and noble-gas atoms....

  5. First-order correction terms in the weak-field asymptotic theory of tunneling ionization

    DEFF Research Database (Denmark)

    Trinh, Vinh H.; Tolstikhin, Oleg I.; Madsen, Lars Bojer;

    2013-01-01

    The weak-field asymptotic theory (WFAT) of tunneling ionization in a static electric field is developed to the next order in field. The first-order corrections to the ionization rate and transverse momentum distribution of the ionized electrons are derived. This extends the region of applicability...... of the WFAT at the quantitative level toward stronger fields, practically up to the boundary between tunneling and over-the-barrier regimes of ionization. The results apply to any atom or molecule treated in the single-active-electron and frozen-nuclei approximations. The theory is illustrated by calculations...

  6. Unclassified Source Term and Radionuclide Data for Corrective Action Unit 98: Frenchman Flat Nevada Test Site, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    Farnham, Irene

    2005-09-01

    Frenchman Flat is one of several areas of the Nevada Test Site (NTS) used for underground nuclear testing (Figure 1-1). These nuclear tests resulted in groundwater contamination in the vicinity of the underground test areas. As a result, the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) is currently conducting a corrective action investigation (CAI) of the Frenchman Flat underground test areas. Since 1996, the Nevada Division of Environmental Protection (NDEP) has regulated NNSA/NSO corrective actions through the ''Federal Facility Agreement and Consent Order'' ([FFACO], 1996). Appendix VI of the FFACO agreement, ''Corrective Action Strategy'', was revised on December 7, 2000, and describes the processes that will be used to complete corrective actions, including those in the Underground Test Area (UGTA) Project. The individual locations covered by the agreement are known as corrective action sites (CASs), which are grouped into corrective action units (CAUs). The UGTA CASs are grouped geographically into five CAUs: Frenchman Flat, Central Pahute Mesa, Western Pahute Mesa, Yucca Flat/Climax Mine, and Rainier Mesa/Shoshone Mountain (Figure 1-1). These CAUs have distinctly different contaminant source, geologic, and hydrogeologic characteristics related to their location (FFACO, 1996). The Frenchman Flat CAU consists of 10 CASs located in the northern part of Area 5 and the southern part of Area 11 (Figure 1-1). This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for Frenchman Flat, CAU 98. The methodology used to estimate hydrologic source terms (HSTs) for the Frenchman Flat CAU is also documented. The HST of an underground nuclear test is the portion of the total inventory of radionuclides that is released over time into the groundwater following the test. The total residual inventory

  7. AAV-based neonatal gene therapy for hemophilia A: long-term correction and avoidance of immune responses in mice.

    Science.gov (United States)

    Hu, C; Lipshutz, G S

    2012-12-01

    Hemophilia A gene therapy has been hampered by immune responses to vector-associated antigens and by neutralizing antibodies or inhibitors against the factor VIII (FVIII) protein; these 'inhibitors' more commonly affect hemophilia A patients than those with hemophilia B. A gene replacement strategy beginning in the neonatal period may avoid the development of these immune responses and lead to prolonged expression with correction of phenotype, thereby avoiding long-term consequences. A serotype rh10 adeno-associated virus (AAV) was developed splitting the FVIII coding sequence into heavy and light chains with the chicken β-actin promoter/CMV enhancer for dual recombinant adeno-associated viral vector delivery. Virions of each FVIII chain were co-injected intravenously into mice on the second day of life. Mice express sustained levels of FVIII antigen ≥5% up to 22 months of life without development of antibodies against FVIII. Phenotypic correction was manifest in all AAV-FVIII-treated mice as demonstrated by functional assay and reduction in bleeding time. This study demonstrates the use of AAV in a gene replacement strategy in neonatal mice that establishes both long-term phenotypic correction of hemophilia A and lack of antibody development against FVIII in this disease model where AAV is administered shortly after birth. These studies support the consideration of gene replacement therapy for diseases that are diagnosed in utero or in the early neonatal period.

  8. Long-term sex-biased correction of circulating propionic acidemia disease markers by adeno-associated virus vectors.

    Science.gov (United States)

    Guenzel, Adam J; Collard, Renata; Kraus, Jan P; Matern, Dietrich; Barry, Michael A

    2015-03-01

    Propionic academia (PA) occurs because of mutations in the PCCA or PCCB genes encoding the two subunits of propionyl-CoA carboxylase, a pivotal enzyme in the breakdown of certain amino acids and odd-chain fatty acids. There is no cure for PA, but dietary protein restriction and liver transplantation can attenuate its symptoms. We show here that a single intravenous injection of adeno-associated virus 2/8 (AAV8) or AAVrh10 expressing PCCA into PA hypomorphic mice decreased systemic propionylcarnitine and methyl citrate for up to 1.5 years. However, long-term phenotypic correction was always better in male mice. AAV-mediated PCCA expression was similar in most tissues in males and females at early time points and differed only in the liver. Over 1.5 years, luciferase and PCCA expression remained elevated in cardiac tissue for both sexes. In contrast, transgene expression in the liver and skeletal muscles of female, but not male, mice waned—suggesting that these tissues were major sinks for systemic phenotypic correction. These data indicate that single systemic intravenous therapy by AAV vectors can mediate long-term phenotype correction for PA. However, tissue-specific loss of expression in females reduces efficacy when compared with males. Whether similar sex-biased AAV effects occur in human gene therapy remains to be determined.

  9. Correction of Dynamic Errors of a Gas Sensor Based on a Parametric Method and a Neural Network Technique

    Directory of Open Access Journals (Sweden)

    Jerzy Roj

    2016-08-01

    Full Text Available The paper presents two methods of dynamic error correction applied to transducers used for the measurement of gas concentration. One of them is based on a parametric model of the transducer dynamics, and the second one uses the artificial neural network (ANN technique. This article describes research of the dynamic properties of the gas concentration measuring transducer with a typical sensor based on tin dioxide. Its response time is about 8 min, which may be not acceptable in many applications. On the basis of these studies, a parametric model of the transducer dynamics and an adequate correction algorithm has been developed. The results obtained in the research of the transducer were also used for learning and testing ANN, which were implemented in the dynamic correction task. Despite the simplicity of the used models, both methods allowed a significant reduction of the transducer’s response time. For the algorithm based on the parametric model the response time was shorter by approximately eight-fold (reduced up to 40–80 s, i.e., about 2–4 sample periods, whereas with the use of an ANN the output signal was practically fixed after a time equal to one sampling period, i.e., 20 s. In addition, the use of ANN has allowed reducing the impact of the transducer dynamic non-linearity on the correction effectiveness.

  10. Von Bertalanffy's dynamics under a polynomial correction: Allee effect and big bang bifurcation

    Science.gov (United States)

    Leonel Rocha, J.; Taha, A. K.; Fournier-Prunaret, D.

    2016-02-01

    In this work we consider new one-dimensional populational discrete dynamical systems in which the growth of the population is described by a family of von Bertalanffy's functions, as a dynamical approach to von Bertalanffy's growth equation. The purpose of introducing Allee effect in those models is satisfied under a correction factor of polynomial type. We study classes of von Bertalanffy's functions with different types of Allee effect: strong and weak Allee's functions. Dependent on the variation of four parameters, von Bertalanffy's functions also includes another class of important functions: functions with no Allee effect. The complex bifurcation structures of these von Bertalanffy's functions is investigated in detail. We verified that this family of functions has particular bifurcation structures: the big bang bifurcation of the so-called “box-within-a-box” type. The big bang bifurcation is associated to the asymptotic weight or carrying capacity. This work is a contribution to the study of the big bang bifurcation analysis for continuous maps and their relationship with explosion birth and extinction phenomena.

  11. Analytical correction of an extension of the "MU Fraction Approximation" for Varian enhanced dynamic wedges.

    Science.gov (United States)

    Gossman, Michael S; Sharma, Subhash C

    2010-04-01

    The most common method to determine enhanced dynamic wedge factors begins with the use of segmented treatment tables. These segmental dose delivery values set as a function of upper jaw position are the backbone of a calculation process coined the "MU Fraction Approximation." Analytical and theoretical attempts have been made to extend and alter the mathematics for this approximation for greater accuracy. A set of linear equations in the form of a matrix are introduced here which correct one published extension of the MU Fraction Approximation as it applies to both symmetric and asymmetric photon fields. The matrix results are compared to data collected from a commissioned Varian Eclipse Treatment Planning System and previously published research for Varian linear accelerators. A total enhanced dynamic wedge factor with excellent accuracy was achieved in comparison to the most accurate previous research found. The deviation seen here is only 0.4% and 1.0% for symmetric and asymmetric fields respectively, for both 6MV and 18MV photon beams.

  12. Extending the Dynamic Range in Metabolomics Experiments by Automatic Correction of Peaks Exceeding the Detection Limit.

    Science.gov (United States)

    Lisec, Jan; Hoffmann, Friederike; Schmitt, Clemens; Jaeger, Carsten

    2016-08-02

    Metabolomics, the analysis of potentially all small molecules within a biological system, has become a valuable tool for biomarker identification and the elucidation of biological processes. While metabolites are often present in complex mixtures at extremely different concentrations, the dynamic range of available analytical methods to capture this variance is generally limited. Here, we show that gas chromatography coupled to atmospheric pressure chemical ionization mass spectrometry (GC-APCI-MS), a state of the art analytical technology applied in metabolomics analyses, shows an average linear range (LR) of 2.39 orders of magnitude for a set of 62 metabolites from a representative compound mixture. We further developed a computational tool to extend this dynamic range on average by more than 1 order of magnitude, demonstrated with a dilution series of the compound mixture, using robust and automatic reconstruction of intensity values exceeding the detection limit. The tool is freely available as an R package (CorrectOverloadedPeaks) from CRAN ( https://cran.r-project.org/ ) and can be incorporated in a metabolomics data processing pipeline facilitating large screening assays.

  13. Correction: Long-Term Soft Denture Lining Materials. Materials 2014, 7(8, 5816-5842

    Directory of Open Access Journals (Sweden)

    Grzegorz Chladek

    2015-06-01

    Full Text Available In the published manuscript “Long-Term Soft Denture Lining Materials. Materials 2014, 7(8, 5816-5842” [1] we detected that in three places reference numbers were inserted incorrectly due to an error in the editing. [...

  14. Comparative merits of the memory function and dynamic local field correction of the classical one-component plasma

    CERN Document Server

    Mithen, James P; Gregori, G

    2011-01-01

    The complementarity of the liquid and plasma descriptions of the classical one-component plasma (OCP) is explored by studying wavevector and frequency dependent dynamical quantities: the dynamical structure factor (DSF), and the dynamic local field correction (LFC). Accurate Molecular Dynamics (MD) simulations are used to validate/test models of the DSF and LFC. Our simulations, which span the entire fluid regime ($\\Gamma = 0.1 - 175$), show that the DSF is very well represented by a simple and well known memory function model of generalized hydrodynamics. On the other hand, the LFC, which we have computed using MD for the first time, is not well described by existing models.

  15. Intersegmental dynamics are controlled by sequential anticipatory, error correction, and postural mechanisms.

    Science.gov (United States)

    Sainburg, R L; Ghez, C; Kalakanis, D

    1999-03-01

    The purpose of this study is to examine the mechanisms underlying control of intersegmental dynamics during reaching movements. Two experiments were conducted to determine the relative contributions of anticipatory and somatosensory feedback mechanisms in controlling intersegmental dynamics and whether adaptation to novel intersegmental dynamics generalizes across a range of movement directions. The mechanisms used to control interaction torques were examined by altering the inertial load of the forearm. Movements were restricted to the shoulder and elbow and supported on a horizontal plane by a frictionless air-jet system. Subjects made rapid out-and-back movements over a target line presented on a computer screen. The screen cursor disappeared at movement onset, and hand paths were displayed after each movement. After subjects adapted to a novel inertial configuration, the position of an attached mass was changed on pseudorandom trials. During these "surprise" trials, movements were initiated with the torque patterns appropriate to the previously learned inertial condition. As a result, characteristic errors in initial movement direction were predicted by an open-looped forward simulation. After these errors occurred, feedback mediated changes in torque emerged that, surprisingly, further decreased the accuracy of movement reversals. Nevertheless at the end of movement, the hand consistently returned to the starting position. It is plausible that the final position was determined completely by feedback-mediated changes in torque. In a second experiment, adaptation to a novel inertial load during movements made in a single direction showed limited transfer across a range of directions. These findings support and extend those of previous reports, which indicated combined anticipatory and postural mechanisms to coordinate rapid reaching movements. The current results indicate a three-stage control system that sequentially links anticipatory, error correction, and

  16. Numerical studies of relativistic corrections to Fermion dynamics and the Aharonov-Casher effect

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Filho, L.G. [Universidade do Estado, Resende, RJ (Brazil). Faculdade de Tecnologia]. E-mail: gonzaga@fat.uerj.br; Helayel-Neto, J.A.; Murga, J.L.C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mail: helayel@cbpf.br

    2004-05-01

    Dirac equation with minimal electromagnetic coupling yields, in the weakly relativistic regime, the Pauli equation for two-component minimally-interacting electron endowed with magnetic moment coupling and the right value of the Lande g-factor, g=2. On the other hand, another remarkable feature associated with spinning particles is the coupling of the magnetic dipole moment to an electric field, which gives rise to the so-called Aharonov-Casher phase for the wave function of the test particle. This phase shift shows up even though there is no force acting on the particle, just as in the familiar case of the Aharonov-Bohm effect. The most accurate experimental measurements of the spin-electric field interaction are carried out with atomic systems. This work sets out to investigate how the Aharonov-Casher effect may be related to the relativistic regime: in practical terms, how it may appear by means of relativistic corrections to the Schroedinger equation, once an external electromagnetic field is switched on. One should understand at which order of velocities the Aharonov-Casher shift arises, either by adding up higher-order gradient terms to the Schroedinger equation or by carrying out the non-relativistic limit of Dirac equation with higher-derivative terms. The latter has very interesting consequences whenever adjoined to the Dirac equation, leading to a rich excitation spectrum and inducing interesting couplings in the low-energy regime. In view of the calculational complexity inherent to the task of finding solutions to these higher-derivatives partial differential equations, wave-function solutions and phase shifts have to be searched for with the help of numerical methods and computer-algebra software. (author)

  17. Short-Term Dynamical Interactions Among Extrasolar Planets

    Science.gov (United States)

    Laughlin, Gregory; Chambers, John E.; DiVincenzi, Donald (Technical Monitor)

    2001-01-01

    We show that short-term perturbations among massive planets in multiple planet systems can result in radial velocity variations of the central star which differ substantially from velocity variations derived assuming the planets are executing independent Keplerian motions. We discuss two alternate fitting methods which can lead to an improved dynamical description of multiple planet systems. In the first method, the osculating orbital elements are determined via a Levenberg-Marquardt minimization scheme driving an N-body integrator. The second method is an improved analytic model in which orbital elements such as the periods and longitudes of periastron are allowed to vary according to a simple model for resonant interactions between the planets. Both of these methods can potentially determine the true masses for the planets by eliminating the sin(i) degeneracy inherent in fits that assume independent Keplerian motions. As more radial velocity data is accumulated from stars such as GJ876, these methods should allow for unambiguous determination of the planetary masses and relative inclinations.

  18. Study of Fusion Dynamics Using Skyrme Energy Density Formalism with Different Surface Corrections

    Institute of Scientific and Technical Information of China (English)

    Ishwar Dutt; Narinder K. Dhiman

    2010-01-01

    @@ Within the framework of Skyrme energy density formalism, we investigate the role of surface corrections on the fusion of colliding nuclei. The coefficient of surface correction is varied between 1/36 and 4/36, and its impact is studied on about 180 reactions. The detailed investigations indicate a linear relationship between the fusion barrier heights and strength of the surface corrections. Our analysis of the fusion barriers advocate the strength of surface correction of 1/36.

  19. Main corrective measures in an early phase of nuclear power plants’ preparation for safe long term operation

    Energy Technology Data Exchange (ETDEWEB)

    Krivanek, Robert, E-mail: r.krivanek@iaea.org [International Atomic Energy Agency (IAEA), Department of Nuclear Safety and Security, Operational Safety Section, Vienna 1400 (Austria); Fiedler, Jan, E-mail: fiedler@fme.vutbr.cz [University of Technology Brno, Faculty of Mechanical Engineering, Energy Institute, Technická 2896/2, 616 69 Brno (Czech Republic)

    2017-05-15

    Highlights: • Results of SALTO missions provide the most important issues for safe long term operation (LTO) of nuclear power plants. • The most important technical corrective measures in an early phase of preparation for safe LTO are described. • Their satisfactory resolution creates a basis for further activities to demonstrate preparedness for safe LTO. - Abstract: This paper presents the analysis of main technical deficiencies of nuclear power plants (NPPs) in preparedness for safe long term operation (LTO) and the main corrective measures in an early phase of preparation for safe LTO of NPPs. It focuses on technical aspects connected with management of physical ageing of NPP structures, systems and components (SSCs). It uses as a basis results of IAEA SALTO missions performed between 2005 and 2016 (see also paper NED8805 in Nuclear Engineering and Design in May 2016) and the personal experiences of the authors with preparation of NPPs for safe LTO. This paper does not discuss other important aspects of safe LTO of NPPs, e.g. national nuclear energy policies, compliance of NPPs with the latest international requirements on design, obsolescence, environmental impact and economic aspects of LTO. Chapter 1 provides a brief introduction of the current status of the NPP’ fleet in connection with LTO. Chapter 2 provides an overview of SALTO peer review service results with a focus on deficiencies related to physical ageing of safety SSCs and a demonstration that SSCs will perform their safety function during the intended period of LTO. Chapter 3 discusses the main corrective measures which NPPs typically face during the preparation for demonstration of safe LTO. Chapter 4 summarizes the current status of the NPP’ fleet in connection with LTO and outlines further steps needed in preparation for safe LTO.

  20. Correction of static axial alignment in children with knee varus or valgus deformities through guided growth: Does it also correct dynamic frontal plane moments during walking?

    Science.gov (United States)

    Böhm, Harald; Stief, Felix; Sander, Klaus; Hösl, Matthias; Döderlein, Leonhard

    2015-09-01

    Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, pknee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed.

  1. Error correction in multi-fidelity molecular dynamics simulations using functional uncertainty quantification

    Science.gov (United States)

    Reeve, Samuel Temple; Strachan, Alejandro

    2017-04-01

    We use functional, Fréchet, derivatives to quantify how thermodynamic outputs of a molecular dynamics (MD) simulation depend on the potential used to compute atomic interactions. Our approach quantifies the sensitivity of the quantities of interest with respect to the input functions as opposed to its parameters as is done in typical uncertainty quantification methods. We show that the functional sensitivity of the average potential energy and pressure in isothermal, isochoric MD simulations using Lennard-Jones two-body interactions can be used to accurately predict those properties for other interatomic potentials (with different functional forms) without re-running the simulations. This is demonstrated under three different thermodynamic conditions, namely a crystal at room temperature, a liquid at ambient pressure, and a high pressure liquid. The method provides accurate predictions as long as the change in potential can be reasonably described to first order and does not significantly affect the region in phase space explored by the simulation. The functional uncertainty quantification approach can be used to estimate the uncertainties associated with constitutive models used in the simulation and to correct predictions if a more accurate representation becomes available.

  2. Long-term outcome of correction of tetralogy of Fallot in 56 adult patients

    Institute of Scientific and Technical Information of China (English)

    ZHENG Da-wei; SHAO Guo-feng; FENG Qiang; NI Yi-ming

    2013-01-01

    Background Although most patients with tetralogy of Fallot undergo radical repair during infancy and childhood,patients that remain undiagnosed and untreated until adulthood can still be treated.This study aimed to evaluate longterm outcomes of adult patients with tetralogy of Fallot who were treated surgically,and to determine the predictors of postoperative pulmonary regurgitation.Methods Fifty-six adult patients underwent complete surgical repair.Forty-three patients (76.8%) required a transannular patch.Systolic,diastolic,and mean pressure in the main pulmonary artery were measured after repair.Results The early mortality rate was 3.6%.The 16-year survival rate was (84.4±11.5)%.Late echocardiography revealed 41 patients with transannular patch who had pulmonary regurgitation,consisting of mild pulmonary regurgitation in 28 patients,moderate in eight,and severe regurgitation in five patients.In addition,there was right ventricular outflow tract stenosis in nine patients,moderate/severe tricuspid valve regurgitation in seven,and residual ventricular septal defect in five.Logistic regression analysis demonstrated that the mean pulmonary pressure measured just after repair predicted late pulmonary regurgitation.Conclusions The long-term survival of surgically treated adult patients with tetralogy of Fallot is acceptable.The mean pressure >20 mmHg in the main pulmonary artery measured right after surgical repair may be a feasible reference to time the reconstruction of the pulmonary valve.

  3. Long-term Correction in Sleep Disturbance Is Sustained After Arthroscopic Rotator Cuff Repair.

    Science.gov (United States)

    Horneff, John G; Tjoumakaris, Fotios; Wowkanech, Charles; Pepe, Matthew; Tucker, Bradford; Austin, Luke

    2017-06-01

    Sleep disturbance is a major complaint of patients with rotator cuff disease that often leads them to seek treatment. The authors previously reported a prospective analysis of patients who underwent rotator cuff repair and found that sleep disturbance significantly improved at 3 months after surgery. That improvement in sleep was maintained at 6 months. In the current study, the authors sought to gain medium-term data on this same population at greater than 2 years. The hypotheses were that improvement in sleep disturbance after arthroscopic rotator cuff repair is maintained at 2-year follow-up and that the continued use of narcotic pain medication has a negative effect on sleep quality at 2-year follow-up. Case series; Level of evidence, 4. The original cohort of patients was contacted at a minimum of 24 months after their surgery. Thirty-seven of the 56 patients (66%) involved in the original study were available. Patient outcomes were scored using the Pittsburgh Sleep Quality Index (PSQI), Simple Shoulder Test (SST), visual analog scale (VAS) for pain, and Single Assessment Numeric Evaluation (SANE). The newly obtained scores were compared with prior scores, which ranged from preoperatively to 6 months postoperatively. The statistically significant improvement of the PSQI score demonstrated in our prior analysis at 6 months postoperatively was maintained, with a mean PSQI score of 5.5 for the 37 patients followed beyond 24 months. Of those patients, 41% still had a PSQI score >5, indicative of sleep disturbance. However, even those patients in our study with a PSQI score >5, indicative of sleep disturbance, had an improved mean score of 9.3 at greater than 24 months compared with those patients with a PSQI score >5 at 6 months, who had a mean PSQI score of 11.5 ( P = .13). Both the SST and VAS scores displayed continued improvement at greater than 24 months, with both displaying moderate strength correlation to the PSQI score (VAS: Spearman rho = 0.479, P < .001

  4. Examining the limits of time reweighting and Kramers' rate theory to obtain correct kinetics from accelerated molecular dynamics.

    Science.gov (United States)

    Xin, Yao; Doshi, Urmi; Hamelberg, Donald

    2010-06-14

    Accelerated molecular dynamics simulations are routinely being used to recover the correct canonical probability distributions corresponding to the original potential energy landscape of biomolecular systems. However, the limits of time reweighting, based on transition state theory, in obtaining true kinetic rates from accelerated molecular dynamics for biomolecular systems are less obvious. Here, we investigate this issue by studying the kinetics of cis-trans isomerization of peptidic omega bond by accelerated molecular dynamics. We find that time reweighting is valid for obtaining true kinetics when the original potential is not altered at the transition state regions, as expected. When the original potential landscape is modified such that the applied boost potential alters the transition state regions, time reweighting fails to reproduce correct kinetics and the reweighted rate is much slower than the true rate. By adopting the overdamped limit of Kramers' rate theory, we are successful in recovering correct kinetics irrespective of whether or not the transition state regions are modified. Furthermore, we tested the validity of the acceleration weight factor from the path integral formalism for obtaining the correct kinetics of cis-trans isomerization. It was found that this formulation of the weight factor is not suitable for long time scale processes such as cis-trans isomerization with high energy barriers.

  5. Long-term changes of physicochemical parameters and benthos in Lake Qarun (Egypt: Can we make a correct forecast of ecosystem future?

    Directory of Open Access Journals (Sweden)

    Shadrin N. V.

    2016-01-01

    Full Text Available Biotic changes and a salinity increase (from 13 to 40 g.L-1 occurred in Lake Qarun (Egypt since 1901. Was salinity increasing a cause of observed biotic changes? To answer this question we used benthos as a model group. Benthos and water sampling was conducted in different seasons (2008–2013. Comparing our and literature data, we discuss the long-term trends and possible causes of benthos changes. Salinity reached 3 g.L-1 in middle of 19th century; and biotic changes caused by this were started. From middle 19th century to 1928 a biotic transformation was driven by the salinity increase; after 1928 a regular alien species introduction caused that a marine community formed. In 1970–2000 eutrophication played a main role in species composition changes. In 2014 ctenophore Mnemiopsis leidyi introduced in the lake; eutrophication, chemical pollution, and a population dynamics of this ctenophore may be main drivers of the ecosystem change now. Benthos biomass gradually decreased during interval 1975–2013 without any correlation with salinity change. A variety of other factors than salinity may be significant in determining the structure and dynamics of communities, and we conclude that we have a small chance to make a correct forecast of possible future ecosystem changes in Lake Qarun.

  6. On one-loop corrections to matching conditions of lattice HQET including 1/m{sub b} terms

    Energy Technology Data Exchange (ETDEWEB)

    Korcyl, Piotr [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2013-12-15

    HQET is an effective theory for QCD with N{sub f} light quarks and a massive valence quark if the mass of the latter is much bigger than LQCD. As any effective theory, HQET is predictive only when a set of parameters has been determined through a process called matching. The non-perturbative matching procedure including 1/m{sub b} terms, developed by the ALPHA collaboration, consists of 19 carefully chosen observables which are precisely computable in lattice QCD as well as in lattice HQET. The matching conditions are then a set of 19 equations which relate the QCD and HQET values of these observables. We present a study of one-loop corrections to two generic matching observables involving correlation function with an insertion of the A{sub 0} operator. Our results enable us to quantify the quality of the relevant observables in view of the envisaged nonperturbative implementation of this matching procedure.

  7. Mid- to long-term outcome of 96 corrective hindfoot fusions in 84 patients with rigid flatfoot deformity.

    Science.gov (United States)

    Röhm, J; Zwicky, L; Horn Lang, T; Salentiny, Y; Hintermann, B; Knupp, M

    2015-05-01

    Talonavicular and subtalar joint fusion through a medial incision (modified triple arthrodesis) has become an increasingly popular technique for treating symptomatic flatfoot deformity caused by posterior tibial tendon dysfunction. The purpose of this study was to look at its clinical and radiological mid- to long-term outcomes, including the rates of recurrent flatfoot deformity, nonunion and avascular necrosis of the dome of the talus. A total of 84 patients (96 feet) with a symptomatic rigid flatfoot deformity caused by posterior tibial tendon dysfunction were treated using a modified triple arthrodesis. The mean age of the patients was 66 years (35 to 85) and the mean follow-up was 4.7 years (1 to 8.3). Both clinical and radiological outcomes were analysed retrospectively. In 86 of the 95 feet (90.5%) for which radiographs were available, there was no loss of correction at final follow-up. In all, 14 feet (14.7%) needed secondary surgery, six for nonunion, two for avascular necrosis, five for progression of the flatfoot deformity and tibiotalar arthritis and one because of symptomatic overcorrection. The mean American Orthopaedic Foot and Ankle Society Hindfoot score (AOFAS score) at final follow-up was 67 (between 16 and 100) and the mean visual analogue score for pain 2.4 points (between 0 and 10). In conclusion, modified triple arthrodesis provides reliable correction of deformity and a good clinical outcome at mid- to long-term follow-up, with nonunion as the most frequent complication. Avascular necrosis of the talus is a rare but serious complication of this technique.

  8. The Efficacy of Dynamic Written Corrective Feedback for University-Matriculated ESL Learners

    Science.gov (United States)

    Evans, Norman W.; Hartshorn, K. James; Strong-Krause, Diane

    2011-01-01

    Truscott's (1996) indictment on error correction in second-language (L2) writing has ignited much discussion and research on the appropriateness of written corrective feedback (WCF) in L2 contexts. Out of this has emerged a body of research that suggests that WCF can positively impact the linguistic accuracy of student writing. However, these…

  9. Constraint Stabilization and One-Step Correction Method for Dynamical Systems

    Institute of Scientific and Technical Information of China (English)

    SHANG Mei; CHEN Xiang-wei; MEI Feng-xiang

    2007-01-01

    A computational method of constraint stabilization and correction is introduced.The method is based on the Baumgart's one-step method.Constraint conditions are addressed to stabilize and correct the solution.Two examples are given to illustrate the results of the method.

  10. On the simple random-walk models of ion-channel gate dynamics reflecting long-term memory.

    Science.gov (United States)

    Wawrzkiewicz, Agata; Pawelek, Krzysztof; Borys, Przemyslaw; Dworakowska, Beata; Grzywna, Zbigniew J

    2012-06-01

    Several approaches to ion-channel gating modelling have been proposed. Although many models describe the dwell-time distributions correctly, they are incapable of predicting and explaining the long-term correlations between the lengths of adjacent openings and closings of a channel. In this paper we propose two simple random-walk models of the gating dynamics of voltage and Ca(2+)-activated potassium channels which qualitatively reproduce the dwell-time distributions, and describe the experimentally observed long-term memory quite well. Biological interpretation of both models is presented. In particular, the origin of the correlations is associated with fluctuations of channel mass density. The long-term memory effect, as measured by Hurst R/S analysis of experimental single-channel patch-clamp recordings, is close to the behaviour predicted by our models. The flexibility of the models enables their use as templates for other types of ion channel.

  11. Disturbance Dynamics and Ecological Response: The Contribution of Long-Term Ecological Research.

    Science.gov (United States)

    MONICA G. TURNER; SCOTT L. COLLINS; ARIEL L. LUGO; JOHN J. MAGNUSON; T. SCOTT RUPP; FREDERICK J. SWANSON

    2003-01-01

    Long-term ecological research is particularly valuable for understanding disturbance dynamics over long time periods and placing those dynamics in a regional context.We highlighted three case studies from Long Term Ecological Research (LTER) Network sites that have contributed to understanding the causes and consequences of disturbance in ecological systems. The LTER...

  12. Improved UTE-based attenuation correction for cranial PET-MR using dynamic magnetic field monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, A. P.; Giese, D.; Tsoumpas, C.; Schleyer, P.; Kozerke, S.; Prieto, C.; Schaeffter, T., E-mail: Tobias.Schaeffter@kcl.ac.uk [Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, King' s Health Partners, St. Thomas Hospital, London SE1 7EH (United Kingdom)

    2014-01-15

    Purpose: Ultrashort echo time (UTE) MRI has been proposed as a way to produce segmented attenuation maps for PET, as it provides contrast between bone, air, and soft tissue. However, UTE sequences require samples to be acquired during rapidly changing gradient fields, which makes the resulting images prone to eddy current artifacts. In this work it is demonstrated that this can lead to misclassification of tissues in segmented attenuation maps (AC maps) and that these effects can be corrected for by measuring the true k-space trajectories using a magnetic field camera. Methods: The k-space trajectories during a dual echo UTE sequence were measured using a dynamic magnetic field camera. UTE images were reconstructed using nominal trajectories and again using the measured trajectories. A numerical phantom was used to demonstrate the effect of reconstructing with incorrect trajectories. Images of an ovine leg phantom were reconstructed and segmented and the resulting attenuation maps were compared to a segmented map derived from a CT scan of the same phantom, using the Dice similarity measure. The feasibility of the proposed method was demonstrated inin vivo cranial imaging in five healthy volunteers. Simulated PET data were generated for one volunteer to show the impact of misclassifications on the PET reconstruction. Results: Images of the numerical phantom exhibited blurring and edge artifacts on the bone–tissue and air–tissue interfaces when nominal k-space trajectories were used, leading to misclassification of soft tissue as bone and misclassification of bone as air. Images of the tissue phantom and thein vivo cranial images exhibited the same artifacts. The artifacts were greatly reduced when the measured trajectories were used. For the tissue phantom, the Dice coefficient for bone in MR relative to CT was 0.616 using the nominal trajectories and 0.814 using the measured trajectories. The Dice coefficients for soft tissue were 0.933 and 0.934 for the

  13. Surviving in changing seascapes : Sediment dynamics as bottleneck for long-term seagrass presence

    NARCIS (Netherlands)

    Suykerbuyk, Wouter; Bouma, Tjeerd J.; Govers, Laura L.; Giesen, Kris; de Jong, Dick J.; Herman, Peter; Hendriks, Jan; van Katwijk, Marieke M.

    2016-01-01

    Changes in the seascape often result in altered hydrodynamics that lead to coinciding changes in sediment dynamics. Little is known on how altered sediment dynamics affect long-term seagrass persistence. We studied the thresholds of sediment dynamics in relation to seagrass presence by comparing sed

  14. Surviving in Changing Seascapes: Sediment Dynamics as Bottleneck for Long-Term Seagrass Presence

    NARCIS (Netherlands)

    Suykerbuyk, W.; Bouma, T.J.; Govers, L.L.; Giesen, K.; de Jong, D.J.; Herman, P.M.J.; Hendriks, J.; van Katwijk, M.M.

    2016-01-01

    Changes in the seascape often result in altered hydrodynamics that lead to coinciding changes in sediment dynamics. Little is known on how altered sediment dynamics affect long-term seagrass persistence. We studied the thresholds of sediment dynamics in relation to seagrass presence by comparing sed

  15. Quantum Corrections to Classical Molecular Dynamics Simulations of Water and Ice.

    Science.gov (United States)

    Waheed, Qaiser; Edholm, Olle

    2011-09-13

    Classical simulations of simple water models reproduce many properties of the liquid and ice but overestimate the heat capacity by about 65% at ordinary temperatures and much more for low temperature ice. This is due to the fact that the atomic vibrations are quantum mechanical. The application of harmonic quantum corrections to the molecular motion results in good heat capacities for the liquid and for ice at low temperatures but a successively growing positive deviation from experimental results for ice above 200 K that reaches 15% just below melting. We suggest that this deviation is due to the lack of quantum corrections to the anharmonic motions. For the liquid, the anharmonicities are even larger but also softer and thus in less need of quantum correction. Therefore, harmonic quantum corrections to the classically calculated liquid heat capacities result in agreement with the experimental values. The classical model underestimates the heat of melting by 15%, while the application of quantum corrections produces fair agreement. On the other hand, the heat of vaporization is overestimated by 10% in the harmonically corrected classical model.

  16. Dynamics of a Parametrically Excited System with Two Forcing Terms

    Directory of Open Access Journals (Sweden)

    Anastasia Sofroniou

    2014-09-01

    Full Text Available Motivated by the dynamics of a trimaran, an investigation of the dynamic behaviour of a double forcing parametrically excited system is carried out. Initially, we provide an outline of the stability regions, both numerically and analytically, for the undamped linear, extended version of the Mathieu equation. This paper then examines the anticipated form of response of our proposed nonlinear damped double forcing system, where periodic and quasiperiodic routes to chaos are graphically demonstrated and compared with the case of the single vertically-driven pendulum.

  17. Fixed versus dynamic co-occurrence windows in TextRank term weights for information retrieval

    DEFF Research Database (Denmark)

    Lu, Wei; Cheng, Qikai; Lioma, Christina

    2012-01-01

    TextRank is a variant of PageRank typically used in graphs that represent documents, and where vertices denote terms and edges denote relations between terms. Quite often the relation between terms is simple term co-occurrence within a fixed window of k terms. The output of TextRank when applied...... iteratively is a score for each vertex, i.e. a term weight, that can be used for information retrieval (IR) just like conventional term frequency based term weights. So far, when computing TextRank term weights over co-occurrence graphs, the window of term co-occurrence is always fixed. This work departs from...... this, and considers dynamically adjusted windows of term co-occurrence that follow the document structure on a sentence- and paragraph-level. The resulting TextRank term weights are used in a ranking function that re-ranks 1000 initially returned search results in order to improve the precision...

  18. [Morphological changes of peripheral nerve rats under chronic micromercurialism and its pharmacological correction in different terms after injury

    Directory of Open Access Journals (Sweden)

    Shamalо S.N.

    2015-09-01

    Full Text Available Background. Search for new pharmacological agents that activate processes of traumatized nerve regeneration at the condition of mercurial intoxication remains urgent. Objective. The aim of this study was a comparative morphometric analysis of rat peripheral nerve under micromercurialism using antioxidant drug without pharmacotherapy. Methods. Experimental model of sciatic nerve trauma under conditions of chronic micromercurialism was investigated in experiments on two groups of white rats. Micromercurialism was modeled by intraperitoneal injection of mercuric chloride during 10 weeks before sciatic nerve trauma. The rats of the first group received no pharmacological drugs in postoperative period. The second group of animals received 100 μg/kg solution of Thiotriazolinum intraperitoneally daily during 2 weeks after operation. The morphological organization and morphometric data of regenerative neuroma and adjoining parts (proximal and distal of sciatic nerve were studied in 6 and 12 weeks after damage using morphometric and statistic methods. Results. Basing on the results of the second group of animals the average angle of axon deviation from the axis of the nerve in the neuroma sufficiently decreases and distribution density of neuron fibers in distal part increases comparing with the first group. Conclusion. Taken together these data evidence that Thiotriazolinum improves the process of traumatized nerve regeneration. Citation: Shamalо SN. [Morphological changes of peripheral nerve rats under chronic micromercurialism and its pharmacological correction in different terms after injury]. Morphologia. 2015;9(3:95-8. Ukrainian.

  19. Hydrological modelling of alpine headwaters using centurial glacier evolution, snow and long-term discharge dynamics

    Science.gov (United States)

    Kohn, Irene; Vis, Marc; Freudiger, Daphné; Seibert, Jan; Weiler, Markus; Stahl, Kerstin

    2016-04-01

    The response of alpine streamflows to long-term climate variations is highly relevant for the supply of water to adjacent lowlands. A key challenge in modelling high-elevation catchments is the complexity and spatial variability of processes, whereas data availability is rather often poor, restricting options for model calibration and validation. Glaciers represent a long-term storage component that changes over long time-scales and thus introduces additional calibration parameters into the modelling challenge. The presented study aimed to model daily streamflow as well as the contributions of ice and snow melt for all 49 of the River Rhine's glaciated headwater catchments over the long time-period from 1901 to 2006. To constrain the models we used multiple data sources and developed an adapted modelling framework based on an extended version of the HBV model that also includes a time-variable glacier change model and a conceptual representation of snow redistribution. In this study constraints were applied in several ways. A water balance approach was applied to correct precipitation input in order to avoid calibration of precipitation; glacier area change from maps and satellite products and information on snow depth and snow covered area were used for the calibration of each catchment model; and finally, specific seasonal and dynamic aspects of discharge were used for calibration. Additional data like glacier mass balances were used to evaluate the model in selected catchments. The modelling experiment showed that the long-term development of the coupled glacier and streamflow change was particularly important to constrain the model through an objective function incorporating three benchmarks of glacier retreat during the 20th Century. Modelling using only streamflow as calibration criteria had resulted in disproportionate under and over estimation of glacier retreat, even though the simulated and observed streamflow agreed well. Also, even short discharge time

  20. Long-term 4D Geoelectrical Imaging of Moisture Dynamics in an Active Landslide

    Science.gov (United States)

    Uhlemann, S.; Chambers, J. E.; Wilkinson, P. B.; Maurer, H.; Meldrum, P.; Gunn, D.; Smith, A.; Dijkstra, T.

    2016-12-01

    Landslides are a major natural hazard, endangering communities and infrastructure worldwide. Mitigating landslide risk relies on understanding causes and triggering processes, which are often linked to moisture dynamics in slopes causing material softening and elevated pore water pressures. Geoelectrical monitoring is frequently applied to study landslide hydrology. However, its sensitivity to sensor movements has been a challenge for long-term studies on actively failing slopes. Although 2D data acquisition has previously been favoured, it provides limited resolution and relatively poor representation of important 3D landslide structures. We present a novel methodology to incorporate electrode movements into a time-lapse 3D inversion workflow, resulting in a virtually artefact-free time-series of resistivity models. Using temperature correction and laboratory hydro-geophysical relationships, resistivity models are translated into models of moisture content. The data span more than three years, enabling imaging of processes pre- and post landslide reactivation. In the two years before reactivation, the models showed surficial wetting and drying, drainage pathways, and deeper groundwater dynamics. During reactivation, exceptionally high moisture contents were imaged throughout the slope, which was confirmed by independent measurements. Preferential flow was imaged that stabilized parts of the landslide by diverting moisture, and thus dissipating pore pressures, from the slip surface. The results highlight that moisture levels obtained from resistivity monitoring may provide a better activity threshold than rainfall intensity. Based on this work, pro-active remediation measures could be designed and effective early-warning systems implemented. Eventually, resistivity monitoring that can account for moving electrodes may provide a new means for pro-active mitigation of landslide risk, especially for communities and critical infrastructure.

  1. Correcting sequencing errors in DNA coding regions using a dynamic programming approach.

    Science.gov (United States)

    Xu, Y; Mural, R J; Uberbacher, E C

    1995-04-01

    This paper presents an algorithm for detecting and 'correcting' sequencing errors that occur in DNA coding regions. The types of sequencing errors addressed are insertions and deletions (indels) of DNA bases. The goal is to provide a capability which makes single-pass or low-redundancy sequence data more informative, reducing the need for high-redundancy sequencing for gene identification and characterization purposes. This would permit improved sequencing efficiency and reduce genome sequencing costs. The algorithm detects sequencing errors by discovering changes in the statistically preferred reading frame within a putative coding region and then inserts a number of 'neutral' bases at a perceived reading frame transition point to make the putative exon candidate frame consistent. We have implemented the algorithm as a front-end subsystem of the GRAIL DNA sequence analysis system to construct a version which is very error tolerant and also intend to use this as a testbed for further development of sequencing error-correction technology. Preliminary test results have shown the usefulness of this algorithm and also exhibited some of its weakness, providing possible directions for further improvement. On a test set consisting of 68 human DNA sequences with 1% randomly generated indels in coding regions, the algorithm detected and corrected 76% of the indels. The average distance between the position of an indel and the predicted one was 9.4 bases. With this subsystem in place, GRAIL correctly predicted 89% of the coding messages with 10% false message on the 'corrected' sequences, compared to 69% correctly predicted coding messages and 11% falsely predicted messages on the 'corrupted' sequences using standard GRAIL II method (version 1.2).(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Long term structural dynamics of mechanical systems with local nonlinearities

    NARCIS (Netherlands)

    Fey, R.H.B.; Campen, D.H. van; Kraker, A. de

    1996-01-01

    This paper deals with the long term behavior of periodically excited mechanical systems consisting of linear components and local nonlinearities. The number of degrees of freedom of the linear components is reduced by applying a component mode synthesis technique. Lyapunov exponents are used to iden

  3. Multi-atlas attenuation correction supports full quantification of static and dynamic brain PET data in PET-MR

    Science.gov (United States)

    Mérida, Inés; Reilhac, Anthonin; Redouté, Jérôme; Heckemann, Rolf A.; Costes, Nicolas; Hammers, Alexander

    2017-04-01

    In simultaneous PET-MR, attenuation maps are not directly available. Essential for absolute radioactivity quantification, they need to be derived from MR or PET data to correct for gamma photon attenuation by the imaged object. We evaluate a multi-atlas attenuation correction method for brain imaging (MaxProb) on static [18F]FDG PET and, for the first time, on dynamic PET, using the serotoninergic tracer [18F]MPPF. A database of 40 MR/CT image pairs (atlases) was used. The MaxProb method synthesises subject-specific pseudo-CTs by registering each atlas to the target subject space. Atlas CT intensities are then fused via label propagation and majority voting. Here, we compared these pseudo-CTs with the real CTs in a leave-one-out design, contrasting the MaxProb approach with a simplified single-atlas method (SingleAtlas). We evaluated the impact of pseudo-CT accuracy on reconstructed PET images, compared to PET data reconstructed with real CT, at the regional and voxel levels for the following: radioactivity images; time-activity curves; and kinetic parameters (non-displaceable binding potential, BPND). On static [18F]FDG, the mean bias for MaxProb ranged between 0 and 1% for 73 out of 84 regions assessed, and exceptionally peaked at 2.5% for only one region. Statistical parametric map analysis of MaxProb-corrected PET data showed significant differences in less than 0.02% of the brain volume, whereas SingleAtlas-corrected data showed significant differences in 20% of the brain volume. On dynamic [18F]MPPF, most regional errors on BPND ranged from -1 to  +3% (maximum bias 5%) for the MaxProb method. With SingleAtlas, errors were larger and had higher variability in most regions. PET quantification bias increased over the duration of the dynamic scan for SingleAtlas, but not for MaxProb. We show that this effect is due to the interaction of the spatial tracer-distribution heterogeneity variation over time with the degree of accuracy of the attenuation maps. This

  4. An Improved Dynamical Downscaling Method with GCM Bias Corrections and Its Validation with 30 Years of Climate Simulations

    KAUST Repository

    Xu, Zhongfeng

    2012-09-01

    An improved dynamical downscaling method (IDD) with general circulation model (GCM) bias corrections is developed and assessed over North America. A set of regional climate simulations is performed with the Weather Research and Forecasting Model (WRF) version 3.3 embedded in the National Center for Atmospheric Research\\'s (NCAR\\'s) Community Atmosphere Model (CAM). The GCM climatological means and the amplitudes of interannual variations are adjusted based on the National Centers for Environmental Prediction (NCEP)-NCAR global reanalysis products (NNRP) before using them to drive WRF. In this study, the WRF downscaling experiments are identical except the initial and lateral boundary conditions derived from the NNRP, original GCM output, and bias-corrected GCM output, respectively. The analysis finds that the IDD greatly improves the downscaled climate in both climatological means and extreme events relative to the traditional dynamical downscaling approach (TDD). The errors of downscaled climatological mean air temperature, geopotential height, wind vector, moisture, and precipitation are greatly reduced when the GCM bias corrections are applied. In the meantime, IDD also improves the downscaled extreme events characterized by the reduced errors in 2-yr return levels of surface air temperature and precipitation. In comparison with TDD, IDD is also able to produce a more realistic probability distribution in summer daily maximum temperature over the central U.S.-Canada region as well as in summer and winter daily precipitation over the middle and eastern United States. © 2012 American Meteorological Society.

  5. Dynamic-analogue correction of the decadal change of East Asian summer precipitation in the late 1990s

    Science.gov (United States)

    Gong, Zhiqiang; Li, Shangfeng; Hu, Po; Shen, Baizhu; Feng, Guolin

    2016-06-01

    This paper systematically evaluates the deviations that appear in the hindcasts of the East Asian summer precipitation (EASP) decadal change in the late 1990s in two global coupled models (BCC_CGCM and BCC_CSM). The possible causes for the deviations between the model hindcasts and observations are analyzed. The results show that the hindcasts of EASP by BCC_CGCM and BCC_CSM deviate from observations, with the anomaly correlation coefficient (ACC) being -0.01 and -0.09 for the two models, respectively. The SST anomalies in North and West Pacific and the SST index values predicted by the two models also deviate from the observations, indicating that inconsistent SST fields may be the key factor leading to the deviation in the prediction of the EASP decadal shift. Thus, a dynamic-analogue scheme is proposed to correct the precipitation hindcasts by using SSTs, where SST and EASP are highly correlated, to select historical analogue cases. Cross validations show that the average ACC of the temporal-latitude distribution of the EASP between the corrected hindcasts and observations is 0.18 for BCC_CGCM and 0.02 for BCC_CSM; both are much higher than the uncorrected hindcasts. Applying the dynamic-analogue correction scheme in both models successfully improves prediction of the EASP decadal change in the late 1990s.

  6. Bias Correction in the Dynamic Panel Data Model with a Nonscalar Disturbance Covariance Matrix

    NARCIS (Netherlands)

    Bun, M.J.G.

    2003-01-01

    Approximation formulae are developed for the bias of ordinary and generalized Least Squares Dummy Variable (LSDV) estimators in dynamic panel data models. Results from Kiviet [Kiviet, J. F. (1995), on bias, inconsistency, and efficiency of various estimators in dynamic panel data models, J.

  7. Long-Term Monitoring of Water Dynamics in the Sahel Region Using the Multi-Sar

    Science.gov (United States)

    Bertram, A.; Wendleder, A.; Schmitt, A.; Huber, M.

    2016-06-01

    Fresh water is a scarce resource in the West-African Sahel region, seasonally influenced by droughts and floods. Particularly in terms of climate change, the importance of wetlands increases for flora, fauna, human population, agriculture, livestock and fishery. Hence, access to open water is a key factor. Long-term monitoring of water dynamics is of great importance, especially with regard to the spatio-temporal extend of wetlands and drylands. It can predict future trends and facilitate the development of adequate management strategies. Lake Tabalak, a Ramsar wetland of international importance, is one of the most significant ponds in Niger and a refuge for waterbirds. Nevertheless, human population growth increased the pressure on this ecosystem, which is now degrading for all uses. The main objective of the study is a long-term monitoring of the Lake Tabalak's water dynamics to delineate permanent and seasonal water bodies, using weather- and daytime-independent multi-sensor and multi-temporal Synthetic Aperture Radar (SAR) data available for the study area. Data of the following sensors from 1993 until 2016 are used: Sentinel-1A, TerraSARX, ALOS PALSAR-1/2, Envisat ASAR, RADARSAT-1/2, and ERS-1/2. All SAR data are processed with the Multi-SAR-System, unifying the different characteristics of all above mentioned sensors in terms of geometric, radiometric and polarimetric resolution to a consistent format. The polarimetric representation in Kennaugh elements allows fusing single-polarized data acquired by older sensors with multi-polarized data acquired by current sensors. The TANH-normalization guarantees a consistent and therefore comparable description in a closed data range in terms of radiometry. The geometric aspect is solved by projecting all images to an earth-fixed coordinate system correcting the brightness by the help of the incidence angle. The elevation model used in the geocoding step is the novel global model produced by the TanDEM-X satellite

  8. Dynamic noise correction for IVUS quantitative volume blood flow: methods and numerical validation.

    NARCIS (Netherlands)

    Lupotti, F.A.; Korte, C.L. de; Mastik, F.; Steen, A.F.W. van der

    2002-01-01

    In recent years, a new method to measure transverse blood flow based on the decorrelation of the radio-frequency (RF) signals, has been developed. Transverse blood flow estimation may be influenced by noise. In this paper, we investigated a new correlation-based method for noise correction. The deco

  9. Short-Term Dynamical Interactions Among Extrasolar Planets

    CERN Document Server

    Chambers, J E

    2001-01-01

    We show that short-tem perturbations among massive planets in multiple planet systems can result in radial velocity variations of the central star which differ substantially from velocity variations derived assuming the planets are executing independent Keplerian motions. We discuss two alternate fitting methods which can lead to an improved dynamical description of multiple planet systems. In the first method, the osculating orbital elements are determined via a Levenberg-Marquardt minimization scheme driving an N-body integrator. The second method is an improved analytic model in which orbital elements such as the periods and longitudes of periastron are allowed to vary according to a simple model for resonant interactions between the planets. Both of these methods can potentially determine the true masses for the planets by eliminating the sin(i) degeneracy inherent in fits that assume independent Keplerian motions. As more radial velocity data is accumulated from stars such as GJ 876, these methods should...

  10. [A dynamic model of the extravehicular (correction of extravehicuar) activity space suit].

    Science.gov (United States)

    Yang, Feng; Yuan, Xiu-gan

    2002-12-01

    Objective. To establish a dynamic model of the space suit base on the particular configuration of the space suit. Method. The mass of the space suit components, moment of inertia, mobility of the joints of space suit, as well as the suit-generated torques, were considered in this model. The expressions to calculate the moment of inertia were developed by simplifying the geometry of the space suit. A modified Preisach model was used to mathematically describe the hysteretic torque characteristics of joints in a pressurized space suit, and it was implemented numerically basing on the observed suit parameters. Result. A dynamic model considering mass, moment of inertia and suit-generated torques was established. Conclusion. This dynamic model provides some elements for the dynamic simulation of the astronaut extravehicular activity.

  11. Optimization of nonimaging focusing heliostat in dynamic correction of astigmatism for a wide range of incident angles.

    Science.gov (United States)

    Chong, Kok-Keong

    2010-05-15

    To overcome astigmatism has always been a great challenge in designing a heliostat capable of focusing the sunlight on a small receiver throughout the year. In this Letter, a nonimaging focusing heliostat with a dynamic adjustment of facet mirrors in a group manner has been analyzed for optimizing the astigmatic correction in a wide range of incident angles. This what is to the author's knowledge a new heliostat is not only designed to serve the purpose of concentrating sunlight to several hundreds of suns, but also to significantly reduce the variation of the solar flux distribution with the incident angle.

  12. Explaining Macroeconomic and Term Structure Dynamics Jointly in a Non-linear DSGE Model

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller

    This paper shows how a standard DSGE model can be extended to reproduce the dynamics in the 10 year yield curve for the post-war US economy with a similar degree of precision as in reduced form term structure models. At the same time, we are able to reproduce the dynamics of four key macro...

  13. Estimation of the Rotational Terms of the Dynamic Response Matrix

    Directory of Open Access Journals (Sweden)

    D. Montalvão

    2004-01-01

    Full Text Available The dynamic response of a structure can be described by both its translational and rotational receptances. The latter ones are frequently not considered because of the difficulties in applying a pure moment excitation or in measuring rotations. However, in general, this implies a reduction up to 75% of the complete model. On the other hand, if a modification includes a rotational inertia, the rotational receptances of the unmodified system are needed. In one method, more commonly found in the literature, a so called T-block is attached to the structure. Then, a force, applied to an arm of the T-block, generates a moment together with a force at the connection point. The T-block also allows for angular displacement measurements. Nevertheless, the results are often not quite satisfactory. In this work, an alternative method based upon coupling techniques is developed, in which rotational receptances are estimated without the need of applying a moment excitation. This is accomplished by introducing a rotational inertia modification when rotating the T-block. The force is then applied in its centroid. Several numerical and experimental examples are discussed so that the methodology can be clearly described. The advantages and limitations are identified within the practical application of the method.

  14. Correction of the static-dynamic posture's violation of junior schoolchildren with impaired vision during the process of physical education

    Directory of Open Access Journals (Sweden)

    Yurchenko A.A.

    2012-11-01

    Full Text Available An analysis of special scientific and methodological literature about the importance of researching the static-dynamic posture of junior schoolchildren with impaired vision is present. The study involved 23 children with impaired vision 7-10 years old and 60 healthy peers. Conducting ascertaining pedagogical experiment allowed determine the features of static-dynamic posture's violations of visually impaired junior schoolchildren, as an important component of the individual features of the motor skills development. The results were compared with results of healthy peers. Identified the indicators for which results of junior schoolchildren with impaired vision were significantly lower than those of healthy peers. It was developed practical recommendations for correcting and preventing specific drawbacks. It was shown the effectiveness of training with the proposed complex of physical exercises at 25-30% higher than common program for children 7-10 years old.

  15. Topologically correct quantum nonadiabatic formalism for on-the-fly dynamics

    CERN Document Server

    Joubert-Doriol, Loic; Ryabinkin, Ilya G; Izmaylov, Artur F

    2016-01-01

    On-the-fly quantum nonadiabatic dynamics for large systems greatly benefits from the adiabatic representation readily available from the electronic structure programs. However, frequently occurring in this representation conical intersections introduce non-trivial geometric or Berry phases which require a special treatment for adequate modelling of the nuclear dynamics. We analyze two approaches for nonadiabatic dynamics using the time-dependent variational principle and the adiabatic representation. The first approach employs adiabatic electronic functions with global parametric dependence on the nuclear coordinates. The second approach uses adiabatic electronic functions obtained only at the centres of moving localized nuclear basis functions (e.g. frozen-width Gaussians). Unless a gauge transformation is used to enforce single-valued boundary conditions, the first approach fails to capture the geometric phase. In contrast, the second approach accounts for the geometric phase naturally because of the absenc...

  16. Topologically Correct Quantum Nonadiabatic Formalism for On-the-Fly Dynamics.

    Science.gov (United States)

    Joubert-Doriol, Loïc; Sivasubramanium, Janakan; Ryabinkin, Ilya G; Izmaylov, Artur F

    2017-01-19

    On-the-fly quantum nonadiabatic dynamics for large systems greatly benefits from the adiabatic representation readily available from electronic structure programs. However, conical intersections frequently occurring in this representation introduce nontrivial geometric or Berry phases which require a special treatment for adequate modeling of the nuclear dynamics. We analyze two approaches for nonadiabatic dynamics using the time-dependent variational principle and the adiabatic representation. The first approach employs adiabatic electronic functions with global parametric dependence on the nuclear coordinates. The second approach uses adiabatic electronic functions obtained only at the centers of moving localized nuclear basis functions (e.g., frozen-width Gaussians). Unless a gauge transformation is used to enforce single-valued boundary conditions, the first approach fails to capture the geometric phase. In contrast, the second approach accounts for the geometric phase naturally because of the absence of the global nuclear coordinate dependence in the electronic functions.

  17. Non-Hamiltonian dynamics in optical microcavities resulting from wave-inspired corrections to geometric optics

    Science.gov (United States)

    Altmann, E. G.; DelMagno, G.; Hentschel, M.

    2008-10-01

    We introduce and investigate billiard systems with an adjusted ray dynamics that accounts for modifications of the conventional reflection of rays due to universal wave effects. We show that even small modifications of the specular reflection law have dramatic consequences on the phase space of classical billiards. These include the creation of regions of non-Hamiltonian dynamics, the breakdown of symmetries, and changes in the stability and morphology of periodic orbits. Focusing on optical microcavities, we show that our adjusted dynamics provides the missing ray counterpart to previously observed wave phenomena and we describe how to observe its signatures in experiments. Our findings also apply to acoustic and ultrasound waves and are important in all situations where wavelengths are comparable to system sizes, an increasingly likely situation considering the systematic reduction of the size of electronic and photonic devices.

  18. Non-Hamiltonian dynamics in optical microcavities resulting from wave-inspired corrections to geometric optics

    CERN Document Server

    Altmann, Eduardo G; Hentschel, Martina

    2008-01-01

    We introduce and investigate billiard systems with an adjusted ray dynamics that accounts for modifications of the conventional reflection of rays due to universal wave effects. We show that even small modifications of the specular reflection law have dramatic consequences on the phase space of classical billiards. These include the creation of regions of non-Hamiltonian dynamics, the breakdown of symmetries, and changes in the stability and morphology of periodic orbits. Focusing on optical microcavities, we show that our adjusted dynamics provides the missing ray counterpart to previously observed wave phenomena and we describe how to observe its signatures in experiments. Our findings also apply to acoustic and ultrasound waves and are important in all situations where wavelengths are comparable to system sizes, an increasingly likely situation considering the systematic reduction of the size of electronic and photonic devices.

  19. Long-term dynamics of the hemiparasite Rhinanthus angustifolius and its relationship with vegetation structure

    NARCIS (Netherlands)

    Ameloot, Els; Verheyen, Kris; Bakker, Jan P.; De Vries, Yzaak; Hermy, Martin

    2006-01-01

    Questions: 1. How are the long-term dynamics of the root hemiparasite Rhinanthus angustifolius related to vegetation structure, grassland management and climate? 2. Does R. angustifolius have a long-term impact on standing crop and community composition? Location: A formerly fertilized grassland,

  20. Resistive magnetohydrodynamic reconnection: Resolving long-term, chaotic dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Keppens, R.; Restante, A. L.; Lapenta, G. [Centre for mathematical Plasma-Astrophysics, Department of Mathematics, KU Leuven (Belgium); Porth, O. [Department of Applied Mathematics, The University of Leeds, Leeds LS2 9JT (United Kingdom); Galsgaard, K.; Frederiksen, J. T. [The Niels Bohr Institute, University of Copenhagen, København K (Denmark); Parnell, C. [School of Mathematics and Statistics, University of St. Andrews, Fife (United Kingdom)

    2013-09-15

    In this paper, we address the long-term evolution of an idealised double current system entering reconnection regimes where chaotic behavior plays a prominent role. Our aim is to quantify the energetics in high magnetic Reynolds number evolutions, enriched by secondary tearing events, multiple magnetic island coalescence, and compressive versus resistive heating scenarios. Our study will pay particular attention to the required numerical resolutions achievable by modern (grid-adaptive) computations, and comment on the challenge associated with resolving chaotic island formation and interaction. We will use shock-capturing, conservative, grid-adaptive simulations for investigating trends dominated by both physical (resistivity) and numerical (resolution) parameters, and confront them with (visco-)resistive magnetohydrodynamic simulations performed with very different, but equally widely used discretization schemes. This will allow us to comment on the obtained evolutions in a manner irrespective of the adopted discretization strategy. Our findings demonstrate that all schemes used (finite volume based shock-capturing, high order finite differences, and particle in cell-like methods) qualitatively agree on the various evolutionary stages, and that resistivity values of order 0.001 already can lead to chaotic island appearance. However, none of the methods exploited demonstrates convergence in the strong sense in these chaotic regimes. At the same time, nonperturbed tests for showing convergence over long time scales in ideal to resistive regimes are provided as well, where all methods are shown to agree. Both the advantages and disadvantages of specific discretizations as applied to this challenging problem are discussed.

  1. Dynamic Hybrid Model for Short-Term Electricity Price Forecasting

    Directory of Open Access Journals (Sweden)

    Marin Cerjan

    2014-05-01

    Full Text Available Accurate forecasting tools are essential in the operation of electric power systems, especially in deregulated electricity markets. Electricity price forecasting is necessary for all market participants to optimize their portfolios. In this paper we propose a hybrid method approach for short-term hourly electricity price forecasting. The paper combines statistical techniques for pre-processing of data and a multi-layer (MLP neural network for forecasting electricity price and price spike detection. Based on statistical analysis, days are arranged into several categories. Similar days are examined by correlation significance of the historical data. Factors impacting the electricity price forecasting, including historical price factors, load factors and wind production factors are discussed. A price spike index (CWI is defined for spike detection and forecasting. Using proposed approach we created several forecasting models of diverse model complexity. The method is validated using the European Energy Exchange (EEX electricity price data records. Finally, results are discussed with respect to price volatility, with emphasis on the price forecasting accuracy.

  2. [Albumin corrected anion gap is an independent risk factor for long-term mortality of patients with sepsis].

    Science.gov (United States)

    He, Xiaoli; Liao, Xuelian; Xie, Zhichao; Jiang, Chao; Kang, Yan

    2017-02-01

    To explore whether albumin corrected anion gap (ACAG) is associated with long-term mortality of sepsis patients. Adult patients with a diagnosis of sepsis within the first 24 hours (from December 2013 to December 2014) admitted to the intensive care unit (ICU) were included via the Sepsis database of West China Hospital Sichuan University. To record their long-term survival, patients were followed up by telephone interview one year after enrollment. ACAG was calculated according to the anion gap (AG) level within the first 24 hours admitted to ICU, and patients were divided into normal ACAG group (ACAG 12-20 mmol/L) and high ACAG group (ACAG > 20 mmol/L), and clinical characteristics and 1-year mortality were compared between groups. Patients were also divided into survivors and non-survivors according to the 1-year survival outcome, and multivariate logistic regression analysis was conducted to find independent risk factors for long-term mortality of sepsis patients. A total of 296 sepsis patients were enrolled in the study, with 191 (64.5%) in the high ACAG group and 105 (35.5%) in the normal ACAG group. There were no significant differences in age, gender, acute physiology and chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), Charlson cormobidity index (CCI) and other background variables between groups. Compared with the normal ACAG group, patients who suffered from multiple organ dysfunction syndrome (MODS) in the high ACAG group were more prone to develop renal and gastrointestinal injury (43.5% vs. 25.7%, 52.9% vs. 33.3%, respectively), had significantly higher serum creatinine [SCr (μmol/L): 89.0 (61.0, 148.0) vs. 67.1 (48.0, 86.0)], greater need for continuous renal replacement therapy (CRRT, 16.8% vs. 6.7%), and significantly shorter length of ICU stay and hospital stay [days: 11 (5, 22) vs. 16 (18, 31), 21 (14, 39) vs. 28 (20, 47)], with statistically significant differences (all P year cumulative survival for the

  3. On the relative importance of second-order terms in relativistic dissipative fluid dynamics

    CERN Document Server

    Molnár, E; Denicol, G S; Rischke, D H

    2013-01-01

    In Denicol et al., Phys. Rev. D 85, 114047 (2012), the equations of motion of relativistic dissipative fluid dynamics were derived from the relativistic Boltzmann equation. These equations contain a multitude of terms of second order in Knudsen number, in inverse Reynolds number, or their product. Terms of second order in Knudsen number give rise to non-hyperbolic (and thus acausal) behavior and must be neglected in (numerical) solutions of relativistic dissipative fluid dynamics. The coefficients of the terms which are of the order of the product of Knudsen and inverse Reynolds numbers have been explicitly computed in the above reference, in the limit of a massless Boltzmann gas. Terms of second order in inverse Reynolds number arise from the collision term in the Boltzmann equation, upon expansion to second order in deviations from the single-particle distribution function in local thermodynamical equilibrium. In this work, we compute these second-order terms for a massless Boltzmann gas with constant scatt...

  4. Interaction of short-term depression and firing dynamics in shaping single neuron encoding

    Directory of Open Access Journals (Sweden)

    Ashutosh eMohan

    2013-04-01

    Full Text Available We investigated how the two properties short-term synaptic depression of afferent input and postsynaptic firing dynamics combine to determine the operating mode of a neuron. While several computational roles have been ascribed to either, their interaction has not been studied. We considered two types of short-term synaptic dynamics (release-dependent and release-independent depression and two classes of firing dynamics (regular firing and firing with spike-frequency adaptation. The input-output transformation of the four possible combinations of pre- and postsynaptic dynamics was characterized. Adapting neurons receiving input from release-dependent synapses functioned largely as coincidence detectors. The other three configurations showed properties consistent with integrators, each with distinct features. These results suggest that the operating mode of a neuron is determined by both the pre- and postsynaptic dynamics and that studying them together is necessary to understand emergent properties and their implications for neuronal coding.

  5. Dynamical Response of Catalytic Systems in a CS Corrected Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Dunin-Borkowski, Rafal E.; Boothroyd, Chris

    2010-01-01

    the final state of the catalyst. For fundamental studies of sintering, we used a model system consisting of gold nanoparticles on a boron nitride support. Boron nitride powder was deposited onto a lacey carbon film on a copper grid and sputter coated with 0.7 nm of gold. The Au film readily formed......-vacuum pressures has not been fully bridged, progress has been made towards observing materials in their working environment. Many catalytically active materials consist of metals or metal alloys, which are deposited onto a support material as nanoparticles to optimize the exposed active surface area...... nanoparticles up to 20nm in size. The particles were exposed to 1.3 mbar of H2 gas at 410°C in an image CS corrected FEI Titan 80-300 ETEM. Image sequences were acquired at 2 frames/s. Under these conditions, mobility of the particles was clearly visible, while maintaining lattice resolution of both the BN...

  6. High-accuracy current measurement with low-cost shunts by means of dynamic error correction

    OpenAIRE

    Weßkamp, Patrick; Melbert, Joachim

    2016-01-01

    Measurement of electrical current is often performed by using shunt resistors. Thermal effects due to self-heating and ambient temperature variation limit the achievable accuracy, especially if low-cost shunt resistors with increased temperature coefficients are utilized. In this work, a compensation method is presented which takes static and dynamic temperature drift effects into account and provides a significant reduction of measurement error. A thermal model of the shunt...

  7. Dynamic optical aberration correction with adaptive coded apertures techniques in conformal imaging

    Science.gov (United States)

    Li, Yan; Hu, Bin; Zhang, Pengbin; Zhang, Binglong

    2015-02-01

    Conformal imaging systems are confronted with dynamic aberration in optical design processing. In classical optical designs, for combination high requirements of field of view, optical speed, environmental adaption and imaging quality, further enhancements can be achieved only by the introduction of increased complexity of aberration corrector. In recent years of computational imaging, the adaptive coded apertures techniques which has several potential advantages over more traditional optical systems is particularly suitable for military infrared imaging systems. The merits of this new concept include low mass, volume and moments of inertia, potentially lower costs, graceful failure modes, steerable fields of regard with no macroscopic moving parts. Example application for conformal imaging system design where the elements of a set of binary coded aperture masks are applied are optimization designed is presented in this paper, simulation results show that the optical performance is closely related to the mask design and the reconstruction algorithm optimization. As a dynamic aberration corrector, a binary-amplitude mask located at the aperture stop is optimized to mitigate dynamic optical aberrations when the field of regard changes and allow sufficient information to be recorded by the detector for the recovery of a sharp image using digital image restoration in conformal optical system.

  8. On the dynamical generation of the Maxwell term and scale invariance

    CERN Document Server

    Rabinovici, Eliezer

    2011-01-01

    Gauge theories with no Maxwell term are investigated in various setups. The dynamical generation of the Maxwell term is correlated to the scale invariance properties of the system. This is discussed mainly in the cases where the gauge coupling carries dimensions. The term is generated when the theory contains a scale explicitly, when it is asymptotically free and in particular also when the scale invariance is spontaneously broken. The terms are not generated when the scale invariance is maintained. Examples studied include the large $N$ limit of the $CP^{N-1}$ model in $(2+\\epsilon)$ dimensions, a 3D gauged $\\phi^6$ vector model and its supersymmetric extension. In the latter case the generation of the Maxwell term at a fixed point is explored. The phase structure of the $d=3$ case is investigated in the presence of a Chern-Simons term as well. In the supersymmetric $\\phi^6$ model the emergence of the Maxwell term is accompanied by the dynamical generation of the Chern-Simons term and its multiplet and dynam...

  9. Interplay between relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics of Xe atoms

    Science.gov (United States)

    Toyota, Koudai; Son, Sang-Kil; Santra, Robin

    2017-04-01

    In this paper, we theoretically study x-ray multiphoton ionization dynamics of heavy atoms taking into account relativistic and resonance effects. When an atom is exposed to an intense x-ray pulse generated by an x-ray free-electron laser (XFEL), it is ionized to a highly charged ion via a sequence of single-photon ionization and accompanying relaxation processes, and its final charge state is limited by the last ionic state that can be ionized by a single-photon ionization. If x-ray multiphoton ionization involves deep inner-shell electrons in heavy atoms, energy shifts by relativistic effects play an important role in ionization dynamics, as pointed out in Phys. Rev. Lett. 110, 173005 (2013), 10.1103/PhysRevLett.110.173005. On the other hand, if the x-ray beam has a broad energy bandwidth, the high-intensity x-ray pulse can drive resonant photoexcitations for a broad range of ionic states and ionize even beyond the direct one-photon ionization limit, as first proposed in Nat. Photon. 6, 858 (2012), 10.1038/nphoton.2012.261. To investigate both relativistic and resonance effects, we extend the xatom toolkit to incorporate relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics calculations. Charge-state distributions are calculated for Xe atoms interacting with intense XFEL pulses at a photon energy of 1.5 keV and 5.5 keV, respectively. For both photon energies, we demonstrate that the role of resonant excitations in ionization dynamics is altered due to significant shifts of orbital energy levels by relativistic effects. Therefore, it is necessary to take into account both effects to accurately simulate multiphoton multiple ionization dynamics at high x-ray intensity.

  10. 3-Step dynamical downscaling with empirical correction of sea-surface conditions: application to a CORDEX Africa simulation

    Science.gov (United States)

    Hernández-Díaz, Leticia; Laprise, René; Nikiéma, Oumarou; Winger, Katja

    2016-06-01

    Dynamical downscaling of climate projections over a limited-area domain using a Regional Climate Model (RCM) requires boundary conditions (BC) from a Coupled Global Climate Model (CGCM) simulation. Biases in CGCM-generated BC can have detrimental effects in RCM simulations, so attempts to improve the BC used to drive the RCM simulations are worth exploring. It is in this context that an empirical method involving the bias correction of the sea-surface conditions (SSCs; sea-surface temperature and sea-ice concentration) simulated by a CGCM has been developed: The 3-step dynamical downscaling approach. The SSCs from a CGCM simulation are empirically corrected and used as lower BC over the ocean for an atmosphere-only global climate model (AGCM) simulation, which in turn provides the atmospheric lateral BC to drive the RCM simulation. We analyse the impact of this strategy on the simulation of the African climate, with a special attention to the West African Monsoon (WAM) precipitation, using the fifth-generation Canadian Regional Climate Model (CRCM5) over the CORDEX-Africa domain. The Earth System Model of the Max-Planck-Institut für Meteorologie (MPI-ESM-LR) is used as CGCM and a global version of CRCM5 is used as AGCM. The results indicate that the historical climate is much improved, approaching the skill of reanalysis-driven hindcast simulations. The most remarkable effect of this approach is the positive impact on the simulation of all aspects of the WAM precipitation, mainly due to the correction of SSCs. In fact, our results show that proper sea surface temperature (SST) in the Gulf of Guinea is a necessary condition for an adequate simulation of WAM precipitation, especially over the equatorial region of West Africa. It was found that the climate-change projections under RCP4.5 scenario obtained with the 3-step approach are substantially different from those obtained with usual downscaling approach in which the RCM is directly driven by the CGCM output; in

  11. Relativistic corrections for non-Born-Oppenheimer molecular wave functions expanded in terms of complex explicitly correlated Gaussian functions

    Science.gov (United States)

    Bubin, Sergiy; Stanke, Monika; Adamowicz, Ludwik

    2017-06-01

    In our previous work S. Bubin et al., Chem. Phys. Lett. 647, 122 (2016), 10.1016/j.cplett.2016.01.056, it was established that complex explicitly correlated one-center all-particle Gaussian functions (CECGs) provide effective basis functions for very accurate nonrelativistic molecular non-Born-Oppenheimer calculations. In this work, we advance the molecular CECGs approach further by deriving and implementing algorithms for calculating the leading relativistic corrections within this approach. The algorithms are tested in the calculations of the corrections for all 23 bound pure vibrational states of the HD+ ion.

  12. Semiclassical Tunneling Corrections for Classical Dynamics of Unimolecular Reactions in Polyatomic Molecules.

    Science.gov (United States)

    Qin, Yue

    Scope and method of study. The tunneling effects in isomerization of HONO and HSiOH have been studied by using classical trajectories with semiclassical tunneling corrections. The potential energy surfaces were constructed by using the available ab initio, spectroscopic and thermodynamic data. A constrained classical trajectory method was employed to study the roles of the various vibrational modes and molecular rotation in intramolecular energy transfer in cis trans HONO. Findings and conclusions. The results show that the rate constants for cisto trans are generally larger than transto cis for HONO isomerizations. Excitations of the OH and N=O stretches yield the smallest rate constants while the N -O stretch excitation gives the largest rate for both cis to trans and transto cis. The rate of energy transfer from bath modes to the torsional mode is found to be a dominant factor for determining the tunneling rate. Similar behaviors are found in the isomerization of HSiOH. The Si-O stretch excitation gives the largest rate constants and the OH stretch excitation yields the smallest rate constants for both cisto trans and transto cis isomerizations. The ratio of the decay rate with tunneling correction to that without tunneling increases with decreasing total energy of the system. Furthermore, the rate difference between the cisto trans and trans to cis decreases with increasing the excitation energy. The values of the effective mass along the tunneling coordinate can facilitate or hinder the tunneling probability. We find that tunneling effects plays an important role in the isomerization of HSiOH. Our results also elucidate that the ONO bending and torsional modes are important for the relaxation of the excited OH stretch. Removing the torsional motion eliminates the influence of rotation on the intramolecular vibrational energy relaxation. The effects of constraining the ONO bending plays a much smaller role than does constraining the HON bending for decreasing

  13. Pedagogical terms of correction of motive sphere of persons of ripe years with the purchased blindness by facilities of playing activity

    Directory of Open Access Journals (Sweden)

    Kemkina V.I.

    2011-12-01

    Full Text Available The problem of correction of motive sphere of adults blind facilities of playing activity is considered. The pedagogical terms of correction of motive sphere of adults with the purchased blindness are considered. In experiment took part blind adults at the age 22-35 years. It is set that correction-developing teaching the motive actions of blind adults must be concertedly with the level of their development and the differentiated individual approach is foreseen. It is recommended to be oriented on the level of general development of these people, exposure of their potential and actual motive possibilities. It is well-proven that systematic application of facilities of motive activity is provided by the valuable mastering of vitally important motions, development of motive capabilities and capacity for an orientation in space.

  14. DYNAMICS OF THE ANXIETY DISORDERS IN THE COURSE OF SHORT-TERM PSYCHOTHERAPY

    Directory of Open Access Journals (Sweden)

    T.N. Hmylova

    2008-06-01

    Full Text Available The tendency of psychotherapy modern concepts referring to the short-term forms having been taken into account, we carried out the research aimed at the study of short-term form personality-oriented psychotherapy effect on the anxiety disorder dynamics. 103 patients with neurotic disorders were examined in the neurosis and psychotherapy department of the Bekhterev Psychoneurological Research Institute. The findings revealed the situational and personal anxiety level to be objectively decreased in the short-term group psychotherapy course. The short-term group psychotherapy was proved to bean effective method in anxiety disorders treatment considering indications and limitations.

  15. Polynomial scaling approximations and dynamic correlation corrections to doubly occupied configuration interaction wave functions.

    Science.gov (United States)

    Van Raemdonck, Mario; Alcoba, Diego R; Poelmans, Ward; De Baerdemacker, Stijn; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E; Van Neck, Dimitri; Bultinck, Patrick

    2015-09-14

    A class of polynomial scaling methods that approximate Doubly Occupied Configuration Interaction (DOCI) wave functions and improve the description of dynamic correlation is introduced. The accuracy of the resulting wave functions is analysed by comparing energies and studying the overlap between the newly developed methods and full configuration interaction wave functions, showing that a low energy does not necessarily entail a good approximation of the exact wave function. Due to the dependence of DOCI wave functions on the single-particle basis chosen, several orbital optimisation algorithms are introduced. An energy-based algorithm using the simulated annealing method is used as a benchmark. As a computationally more affordable alternative, a seniority number minimising algorithm is developed and compared to the energy based one revealing that the seniority minimising orbital set performs well. Given a well-chosen orbital basis, it is shown that the newly developed DOCI based wave functions are especially suitable for the computationally efficient description of static correlation and to lesser extent dynamic correlation.

  16. Students' Comparison of Their Trigonometric Answers with the Answers of a Computer Algebra System in Terms of Equivalence and Correctness

    Science.gov (United States)

    Tonisson, Eno; Lepp, Marina

    2015-01-01

    The answers offered by computer algebra systems (CAS) can sometimes differ from those expected by the students or teachers. The comparison of the students' answers and CAS answers could provide ground for discussion about equivalence and correctness. Investigating the students' comparison of the answers gives the possibility to study different…

  17. Error correction in multi-fidelity molecular dynamics simulations using functional uncertainty quantification

    CERN Document Server

    Reeve, Samuel

    2016-01-01

    We use functional, Fr\\'echet, derivatives to quantify how thermodynamic outputs of a molecular dynamics (MD) simulation depend on the potential used to compute atomic interactions. Our approach quantifies the sensitivity of the quantities of interest with respect to the input functions as opposed to its parameters as is done in typical uncertainty quantification methods. We show that the functional sensitivity of the average potential energy and pressure in isothermal, isochoric MD simulations using Lennard-Jones two-body interactions can be used to accurately predict those properties for other interatomic potentials (with different functional forms) without re-running the simulations. This is demonstrated under three different thermodynamic conditions, namely a crystal at room temperature, a liquid at ambient pressure, and a high pressure liquid. The method provides accurate predictions as long as the change in potential does not significantly affect the region in phase space explored by the simulation. The ...

  18. Sensitivity of train stochastic dynamics to long-term evolution of track irregularities

    Science.gov (United States)

    Lestoille, N.; Soize, C.; Funfschilling, C.

    2016-05-01

    The influence of the track geometry on the dynamic response of the train is of great concern for the railway companies, because they have to guarantee the safety of the train passengers in ensuring the stability of the train. In this paper, the long-term evolution of the dynamic response of the train on a stretch of the railway track is studied with respect to the long-term evolution of the track geometry. The characterisation of the long-term evolution of the train response allows the railway companies to start off maintenance operations of the track at the best moment. The study is performed using measurements of the track geometry, which are carried out very regularly by a measuring train. A stochastic model of the studied stretch of track is created in order to take into account the measurement uncertainties in the track geometry. The dynamic response of the train is simulated with a multibody software. A noise is added in output of the simulation to consider the uncertainties in the computational model of the train dynamics. Indicators on the dynamic response of the train are defined, allowing to visualize the long-term evolution of the stability and the comfort of the train, when the track geometry deteriorates.

  19. Bodily tides near the 1:1 spin-orbit resonance: correction to Goldreich's dynamical model

    Science.gov (United States)

    Williams, James G.; Efroimsky, Michael

    2012-12-01

    Spin-orbit coupling is often described in an approach known as " the MacDonald torque", which has long become the textbook standard due to its apparent simplicity. Within this method, a concise expression for the additional tidal potential, derived by MacDonald (Rev Geophys 2:467-541, 1994), is combined with a convenient assumption that the quality factor Q is frequency-independent (or, equivalently, that the geometric lag angle is constant in time). This makes the treatment unphysical because MacDonald's derivation of the said formula was, very implicitly, based on keeping the time lag frequency-independent, which is equivalent to setting Q scale as the inverse tidal frequency. This contradiction requires the entire MacDonald treatment of both non-resonant and resonant rotation to be rewritten. The non-resonant case was reconsidered by Efroimsky and Williams (Cel Mech Dyn Astron 104:257-289, 2009), in application to spin modes distant from the major commensurabilities. In the current paper, we continue this work by introducing the necessary alterations into the MacDonald-torque-based model of falling into a 1-to-1 resonance. (The original version of this model was offered by Goldreich (Astron J 71:1-7, 1996). Although the MacDonald torque, both in its original formulation and in its corrected version, is incompatible with realistic rheologies of minerals and mantles, it remains a useful toy model, which enables one to obtain, in some situations, qualitatively meaningful results without resorting to the more rigorous (and complicated) theory of Darwin and Kaula. We first address this simplified model in application to an oblate primary body, with tides raised on it by an orbiting zero-inclination secondary. (Here the role of the tidally-perturbed primary can be played by a satellite, the perturbing secondary being its host planet. A planet may as well be the perturbed primary, its host star acting as the tide-raising secondary). We then extend the model to a

  20. The dynamic effect of exchange-rate volatility on Turkish exports: Parsimonious error-correction model approach

    Directory of Open Access Journals (Sweden)

    Demirhan Erdal

    2015-01-01

    Full Text Available This paper aims to investigate the effect of exchange-rate stability on real export volume in Turkey, using monthly data for the period February 2001 to January 2010. The Johansen multivariate cointegration method and the parsimonious error-correction model are applied to determine long-run and short-run relationships between real export volume and its determinants. In this study, the conditional variance of the GARCH (1, 1 model is taken as a proxy for exchange-rate stability, and generalized impulse-response functions and variance-decomposition analyses are applied to analyze the dynamic effects of variables on real export volume. The empirical findings suggest that exchangerate stability has a significant positive effect on real export volume, both in the short and the long run.

  1. Vapor pressures and heats of sublimation of crystalline β-cellobiose from classical molecular dynamics simulations with quantum mechanical corrections.

    Science.gov (United States)

    Wohlert, Jakob

    2014-05-22

    In this paper, we report the calculation of the enthalpy of sublimation, Δ(sub)H, as a function of temperature of crystalline β-cellobiose from molecular dynamics (MD) simulations, using two popular carbohydrate force fields. Together with the entropy difference between the solid and the vapor, ΔS, evaluated at atmospheric pressure, Δ(sub)H gives the vapor pressure of cellobiose over the solid phase as a function of T. It is found that when quantum mechanical corrections to the enthalpy calculated from the distribution of normal modes is applied both force fields give Δ(sub)H close to experiments. The entropy change, ΔS, which is calculated within a harmonic approximation becomes too small, leading to vapor pressures that are too low. These findings are relevant to MD simulations of crystalline carbohydrates in general, e.g., native cellulose.

  2. Adaptive Correction from Virtually Complex Dynamic Libraries: The Role of Noncovalent Interactions in Structural Selection and Folding.

    Science.gov (United States)

    Lafuente, Maria; Atcher, Joan; Solà, Jordi; Alfonso, Ignacio

    2015-11-16

    The hierarchical self-assembling of complex molecular systems is dictated by the chemical and structural information stored in their components. This information can be expressed through an adaptive process that determines the structurally fittest assembly under given environmental conditions. We have set up complex disulfide-based dynamic covalent libraries of chemically and topologically diverse pseudopeptidic compounds. We show how the reaction evolves from very complex mixtures at short reaction times to the almost exclusive formation of a major compound, through the establishment of intramolecular noncovalent interactions. Our experiments demonstrate that the systems evolve through error-check and error-correction processes. The nature of these interactions, the importance of the folding and the effects of the environment are also discussed.

  3. Gyroscopic corrections improve wearable sensor data prior to measuring dynamic sway in the gait of people with Multiple Sclerosis.

    Science.gov (United States)

    Brodie, Matthew A D; Psarakis, Michael; Hoang, Phu

    2016-09-01

    Accelerometers are incorporated into many consumer devices providing new ways to monitor gait, mobility, and fall risk. However, many health benefits have not been realised because of issues with data quality that results from gravitational 'cross-talk' when the wearable device is tilted. Here we present an adaptive filter designed to improve the quality of accelerometer data prior to measuring dynamic pelvic sway patterns during a six minute walk test in people with and without Multiple Sclerosis (MS). Optical motion capture was used as the gold standard. Improved wearable device accuracy (≤4.4% NRMSE) was achieved using gyroscopic corrections and scaling filter thresholds by step frequency. The people with MS presented significantly greater pelvis sway range to compensate for their lower limb weaknesses and joint contractures. The visualisation of asymmetric pelvic sway in people with MS illustrates the potential to better understand their mobility impairments for reducing fall risk.

  4. Effect of water chemistry upsets on the dynamics of corrective reagent dosing systems at thermal power stations

    Science.gov (United States)

    Voronov, V. N.; Yegoshina, O. V.; Bolshakova, N. A.; Yarovoi, V. O.; Latt, Aie Min

    2016-12-01

    Typical disturbances in the dynamics of a corrective reagent dosing system under unsteady-state conditions during the unsatisfactory operation of a chemical control system with some water chemistry upsets at thermal and nuclear power stations are considered. An experimental setup representing a physical model for the water chemistry control system is described. The two disturbances, which are most frequently encountered in water chemistry control practice, such as a breakdown or shutdown of temperature compensation during pH measurement and an increase in the heat-transfer fluid flow rate, have been modeled in the process of study. The study of the effect produced by the response characteristics of chemical control analyzers on the operation of a reagent dosing system under unsteady-state conditions is important for the operative control of a water chemistry regime state. The effect of temperature compensation during pH measurement on the dynamics of an ammonia-dosing system in the manual and automatic cycle chemistry control modes has been studied. It has been demonstrated that the reading settling time of a pH meter in the manual ammonia- dosing mode grows with a breakdown in temperature compensation and a simultaneous increase in the temperature of a heat-transfer fluid sample. To improve the efficiency of water chemistry control, some systems for the quality control of a heat-transfer fluid by a chemical parameter with the obligatory compensation of a disturbance in its flow rate have been proposed for use. Experimental results will possibly differ from industrial data due to a great length of sampling lines. For this reason, corrective reagent dosing systems must be adapted to the conditions of a certain power-generating unit in the process of their implementation.

  5. Explaining Macroeconomic and Term Structure Dynamics Jointly in a Non-linear DSGE Model

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller

    This paper shows how a standard DSGE model can be extended to reproduce the dynamics in the 10 year yield curve for the post-war US economy with a similar degree of precision as in reduced form term structure models. At the same time, we are able to reproduce the dynamics of four key macro...... variables almost perfectly. Our extension of a standard DSGE model is to introduce three non-stationary shocks which allow us to explain interest rates with medium and long maturities without distorting the dynamics of the macroeconomy....

  6. Correction of vibrational broadening in molecular dynamics clusters with the normal mode optimization method.

    Science.gov (United States)

    Hudecová, Jana; Hopmann, Kathrin H; Bouř, Petr

    2012-01-12

    Vibrational properties of solutions are frequently simulated with clusters of a solute and a few solvent molecules obtained during molecular dynamics (MD) simulations. The raw cluster geometries, however, often provide unrealistic vibrational band broadening, for both ab initio and empirical force fields. In this work, partial optimization in normal-mode coordinates is used on empirical basis to reduce the broadening. The origin of the error is discussed on a simplified two-dimensional system, which indicates that the problem is caused by the anharmonic MD potential, mode coupling, and neglect of quantum effects. Then the procedure of partial geometry optimization on Raman and Raman optical activity (ROA) spectra is applied and analyzed for the solvated lactamide molecule. Comparison to experiment demonstrates that the normal-mode partial optimization technique with a suitable frequency limit can significantly reduce the broadening error. For lactamide, experimental and simulated vibrational bandwidths are compared; the most realistic theoretical spectra are obtained for partially optimized clusters with the vibrational wavenumber cutoff of about 200 cm(-1).

  7. Coordinated approaches to quantify long-term ecosystem dynamics in response to global change

    DEFF Research Database (Denmark)

    Liu, Y.; Melillo, J.; Niu, S.

    2011-01-01

    Many serious ecosystem consequences of climate change will take decades or even centuries to emerge. Long-term ecological responses to global change are strongly regulated by slow processes, such as changes in species composition, carbon dynamics in soil and by long-lived plants, and accumulation...

  8. Long-term effects of climate change on vegetation and carbon dynamics in peat bogs

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Mauquoy, D.; van Geel, B.; Berendse, F.

    2008-01-01

    Questions: What are the long-term effects of climate change on the plant species composition and carbon sequestration in peat bogs? Methods: We developed a bog ecosystem model that includes vegetation, carbon, nitrogen and water dynamics. Two groups of vascular plant species and three groups of Spha

  9. Incorporating Short Term Dynamic Psychotherapy Principles into Career Counseling: A Theoretical and Practical Approach.

    Science.gov (United States)

    Nevo, Ofra; Wiseman, Hadas

    2002-01-01

    The Developmental Career Counseling model incorporates the following principles of Short-Term Dynamic Psychotherapy: life-span approach, limited time, working alliance, rapid and early assessment, central focus, active and directive counselor participation, therapeutic flexibility, and termination issues. The model enables career and personal…

  10. Long-term pigment dynamics and diatom survival in dark sediment

    NARCIS (Netherlands)

    Veuger, B.; Van Oevelen, D.

    2011-01-01

    In order to investigate survival of diatoms and long-term pigment dynamics in dark sediment, we incubated samples of homogenized, sieved, tidal-flat sediment for 1 yr in darkness. Microscopic observations revealed that some diatoms survived the full year in darkness and retained their pigments.

  11. Long-term pigment dynamics and diatom survival in dark sediment

    NARCIS (Netherlands)

    Veuger, B.; Van Oevelen, D.

    2011-01-01

    In order to investigate survival of diatoms and long-term pigment dynamics in dark sediment, we incubated samples of homogenized, sieved, tidal-flat sediment for 1 yr in darkness. Microscopic observations revealed that some diatoms survived the full year in darkness and retained their pigments. Conc

  12. Short-term synaptic depression and stochastic vesicle dynamics reduce and shape neuronal correlations.

    Science.gov (United States)

    Rosenbaum, Robert; Rubin, Jonathan E; Doiron, Brent

    2013-01-01

    Correlated neuronal activity is an important feature in many neural codes, a neural correlate of a variety of cognitive states, as well as a signature of several disease states in the nervous system. The cellular and circuit mechanics of neural correlations is a vibrant area of research. Synapses throughout the cortex exhibit a form of short-term depression where increased presynaptic firing rates deplete neurotransmitter vesicles, which transiently reduces synaptic efficacy. The release and recovery of these vesicles are inherently stochastic, and this stochasticity introduces variability into the conductance elicited by depressing synapses. The impact of spiking and subthreshold membrane dynamics on the transfer of neuronal correlations has been studied intensively, but an investigation of the impact of short-term synaptic depression and stochastic vesicle dynamics on correlation transfer is lacking. We find that short-term synaptic depression and stochastic vesicle dynamics can substantially reduce correlations, shape the timescale over which these correlations occur, and alter the dependence of spiking correlations on firing rate. Our results show that short-term depression and stochastic vesicle dynamics need to be taken into account when modeling correlations in neuronal populations.

  13. Exploring Euclidean Dynamical Triangulations with a Non-trivial Measure Term

    CERN Document Server

    Coumbe, Daniel

    2014-01-01

    We investigate a nonperturbative formulation of quantum gravity defined via Euclidean dynamical triangulations (EDT) with a non-trivial measure term in the path integral. We are motivated to revisit this older formulation of dynamical triangulations by hints from renormalization group approaches that gravity may be asymptotically safe and by the emergence of a semiclassical phase in causal dynamical triangulations (CDT). We study the phase diagram of this model and identify the two phases that are well known from previous work: the branched polymer phase and the collapsed phase. We verify that the order of the phase transition dividing the branched polymer phase from the collapsed phase is almost certainly first-order. The nontrivial measure term enlarges the phase diagram, allowing us to explore a region of the phase diagram that has been dubbed the crinkled region. Although the collapsed and branched polymer phases have been studied extensively in the literature, the crinkled region has not received the sam...

  14. Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

    Science.gov (United States)

    Fujiwara, Takahisa; Suzuki, Yoshihisa; Yoshizaki, Izumi; Tsukamoto, Katsuo; Murayama, Kenta; Fukuyama, Seijiro; Hosokawa, Kouhei; Oshi, Kentaro; Ito, Daisuke; Yamazaki, Tomoya; Tachibana, Masaru; Miura, Hitoshi

    2015-08-01

    The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution.

  15. Long-term results of clear lens extraction combined with piggyback intraocular lens implantation to correct high hyperopia

    Directory of Open Access Journals (Sweden)

    Xia Hua

    2013-10-01

    Full Text Available AIM: To assess the refractive outcome of clear lensectomy combined with piggyback intraocular lens implantation in highly hyperopic patients.METHODS: This case review included 19 eyes of 10 patients with high hyperopia and axial length less than 21mm. Intraocular lens power was calculated for emmetropia using the Holladay II formula in 17 eyes, and SRK/T formula in 2 eyes following clear lens extraction and piggyback intraocular lens implantation. Patients were examined periodically over 24 months for visual acuity and spherical equivalent (SE.RESULTS: The mean postoperative SE at 24 months was 0.20±1.39D (range, -3.00 to 2.50D, better than preoperative 9.81±2.62D (range, +6.00 to +14.50D (PPP=0.34. Twelve eyes maintained and 1 gained 1 or more Snellen line of BCVA, 4 eyes lost 1 line, and 2 eyes lost 2 lines at 24 postoperative months. Twelve eyes best-corrected near visual acuity (BCNVA achieved J1 at postoperative 24 months compared to preoperative 7 eyes and the other 7 eyes better than J3.CONCLUSION: Clear lens extraction combined piggyback intraocular lens implantation appears to be an effective procedure to correct high hyperopia but mild overcorrection and intralenticular opacification may require secondary procedure.

  16. Dynamics and BPS states of AdS5 supergravity with a Gauss-Bonnet term

    CERN Document Server

    Miskovic, O; Zanelli, J; Miskovic, Olivera; Troncoso, Ricardo; Zanelli, Jorge

    2006-01-01

    Some dynamical aspects of five-dimensional supergravity as a Chern-Simons theory for the SU(2,2|N) group, are analyzed. The gravitational sector is described by the Einstein-Hilbert action with negative cosmological constant and a Gauss-Bonnet term with a fixed coupling. The interaction between matter and gravity is characterized by intricate couplings which give rise to dynamical features not present in standard theories. Depending on the location in phase space, the dynamics can possess different number of propagating degrees of freedom, including purely topological sectors. This inhomogeneity of phase space requires special care in the analysis. Background solutions in the canonical sectors, which have regular dynamics with maximal number of degrees of freedom, are shown to exist. Within this class, explicit solutions given by locally AdS spacetimes with nontrivial gauge fields are constructed, and BPS states are identified. It is shown that the charge algebra acquires a central extension due to the presen...

  17. Investigating existence of chaos in short and long term dynamics of Moroccan exchange rates

    Science.gov (United States)

    Lahmiri, Salim

    2017-01-01

    This paper proposes a new methodology to investigate presence of chaos in exchange rate time series by combining wavelet transform and Lyapunov exponent estimation. In particular, stationary wavelet transform (SWT) is applied to exchange rate original time series for decomposition purpose. As a result, approximation and details coefficients are extracted. They are used to represent long and short term dynamics of the original exchange rate time series. Then, largest Lyapunov exponent is estimated for each type of dynamics to check for presence of chaos. Our methodology is applied to several Moroccan exchange rate time series. The empirical results show that, in general, the hypothesis of chaotic structure is accepted for currency levels but it is rejected for currency returns on both long and short dynamics. In addition, long and short dynamics exhibit different chaotic patterns in some exchange rate time series. Our approach may be useful to understand chaotic behaviour in original exchange rate time series.

  18. Crown lengthening procedure following intentional endodontic therapy for correction of supra-erupted posterior teeth: Case series with long-term follow-up

    Directory of Open Access Journals (Sweden)

    Shruti Arun Patil

    2016-01-01

    Full Text Available Context: The crown lengthening procedure (CLP is routinely carried out to correct gingival levels and achieve esthetic contours and adequate crown lengths for restorative purposes. Though the short-term outcomes have been found to be stable, long-term results are not much reported. Aims: To evaluate the long-term stability of the marginal bone levels, gingival levels, and the status of the teeth, which underwent endodontic therapy, followed by CLP and final restorations. Settings and Design: Institutional setting, long-term case series. Materials and Methods: Case records of the patients who underwent CLP and endodontic therapy for corrections of the supra-erupted teeth to regain the lost interocclusal spaces were retrieved, and the cases with complete set of the clinical and radiographs were taken. All the cases were recalled and bone levels on the radiographs, bleeding on probing, probing pocket depths, and changes in the soft tissue margins were evaluated. Statistical Analysis Used: Descriptive analysis. Results: A total of 25 teeth had undergone CLP and endodontic therapy and final restorations for a minimum of 24 months. The mean post-restorative duration was 50.8 ± 22.48 months (range 24–96 months. All the teeth were functional and asymptomatic with 100% survival. Interdental bone loss of 1 mm, probing pockets of 5 mm, and 1 mm buccal recession were observed in 16% of the sites. The amount of interocclusal space regained was adequate to restore the missing teeth in the opposing arch. Conclusions: The CLP is a predictive procedure for correction of supra-erupted teeth. The survival of the teeth that underwent the procedure in the present study was 100% over 24–96 months.

  19. Self-correcting Multigrid Solver

    Energy Technology Data Exchange (ETDEWEB)

    Jerome L.V. Lewandowski

    2004-06-29

    A new multigrid algorithm based on the method of self-correction for the solution of elliptic problems is described. The method exploits information contained in the residual to dynamically modify the source term (right-hand side) of the elliptic problem. It is shown that the self-correcting solver is more efficient at damping the short wavelength modes of the algebraic error than its standard equivalent. When used in conjunction with a multigrid method, the resulting solver displays an improved convergence rate with no additional computational work.

  20. Exploring the dynamics of balance data - movement variability in terms of drift and diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Gottschall, Julia [Institute of Physics, University of Oldenburg, D-26111 Oldenburg (Germany)], E-mail: julia.gottschall@uni-oldenburg.de; Peinke, Joachim [Institute of Physics, University of Oldenburg, D-26111 Oldenburg (Germany)], E-mail: peinke@uni-oldenburg.de; Lippens, Volker [Department of Human Movement, University of Hamburg, Moller Street 10, D-20148 Hamburg (Germany)], E-mail: vlippens@uni-hamburg.de; Nagel, Volker [Department of Human Movement, University of Hamburg, Moller Street 10, D-20148 Hamburg (Germany)

    2009-02-23

    We introduce a method to analyze postural control on a balance board by reconstructing the underlying dynamics in terms of a Langevin model. Drift and diffusion coefficients are directly estimated from the data and fitted by a suitable parametrization. The governing parameters are utilized to evaluate balance performance and the impact of supra-postural tasks on it. We show that the proposed method of analysis gives not only self-consistent results but also provides a plausible model for the reconstruction of balance dynamics.

  1. Long-term social dynamics drive loss of function in pathogenic bacteria

    DEFF Research Database (Denmark)

    Breum Andersen, Sandra; Marvig, Rasmus Lykke; Molin, Søren;

    2015-01-01

    Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly...... social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung...

  2. Exploring the dynamics of balance data — movement variability in terms of drift and diffusion

    Science.gov (United States)

    Gottschall, Julia; Peinke, Joachim; Lippens, Volker; Nagel, Volker

    2009-02-01

    We introduce a method to analyze postural control on a balance board by reconstructing the underlying dynamics in terms of a Langevin model. Drift and diffusion coefficients are directly estimated from the data and fitted by a suitable parametrization. The governing parameters are utilized to evaluate balance performance and the impact of supra-postural tasks on it. We show that the proposed method of analysis gives not only self-consistent results but also provides a plausible model for the reconstruction of balance dynamics.

  3. Synaptic scaling enables dynamically distinct short- and long-term memory formation.

    Directory of Open Access Journals (Sweden)

    Christian Tetzlaff

    2013-10-01

    Full Text Available Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling - a slow process usually associated with the maintenance of activity homeostasis - combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The interaction between plasticity and scaling provides also an explanation for an established paradox where memory consolidation critically depends on the exact order of learning and recall. These results indicate that scaling may be fundamental for stabilizing memories, providing a dynamic link between early and late memory formation processes.

  4. Synaptic scaling enables dynamically distinct short- and long-term memory formation.

    Science.gov (United States)

    Tetzlaff, Christian; Kolodziejski, Christoph; Timme, Marc; Tsodyks, Misha; Wörgötter, Florentin

    2013-10-01

    Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling - a slow process usually associated with the maintenance of activity homeostasis - combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The interaction between plasticity and scaling provides also an explanation for an established paradox where memory consolidation critically depends on the exact order of learning and recall. These results indicate that scaling may be fundamental for stabilizing memories, providing a dynamic link between early and late memory formation processes.

  5. Methods of Correcting Intestine Dysbiosis and Their Influence on the Dynamics of Clinical Manifestations of Hepatic Encephalopathy among Patients with Liver Cirrhosis

    Directory of Open Access Journals (Sweden)

    YE.S. SIRCHAK

    2014-06-01

    Full Text Available Here are given the results of a complex survey of 169 patients with liver cirrhosis having signs of liver encephalopathy. We found more significant positive dynamics of clinical manifestations of liver encephalopathy in patients (n = 70, for whom for correcting microbiocenosis of the colon we prescribed in complex therapy not only prebiotics, but also probiotics.

  6. Development of a baseline-temperature correction methodology for electrochemical sensors and its implications for long-term stability

    Science.gov (United States)

    Popoola, Olalekan A. M.; Stewart, Gregor B.; Mead, Mohammed I.; Jones, Roderic L.

    2016-12-01

    Recent studies have shown that (three-electrode) electrochemical sensors can be utilised for air quality monitoring and exposure assessment. The long-term performance of these sensors is however, often limited by the effects of ambient meteorological parameters on the sensor baseline, in particular temperature. If electrochemical (EC) sensors are to be adopted for air quality measurement over extended periods (months), this effect must be accounted for. Recent long-term, ambient measurements of CO, NO and NO2 using EC sensors have revealed that temperature (and relative humidity (RH)) had an effect on the baseline which was more pronounced in the case of NO sensors with coefficient of determination, R2 of 0.9 when compared to CO and NO2 with R2 air quality gases at the parts per billion volume (ppb) mixing ratio level typical of ambient conditions in the urban environment.

  7. Classifying genes to the correct Gene Ontology Slim term in Saccharomyces cerevisiae using neighbouring genes with classification learning

    OpenAIRE

    Tsatsoulis Costas; Amthauer Heather A

    2010-01-01

    Abstract Background There is increasing evidence that gene location and surrounding genes influence the functionality of genes in the eukaryotic genome. Knowing the Gene Ontology Slim terms associated with a gene gives us insight into a gene's functionality by informing us how its gene product behaves in a cellular context using three different ontologies: molecular function, biological process, and cellular component. In this study, we analyzed if we could classify a gene in Saccharomyces ce...

  8. Leakage correction estimate for electret ion chamber dielectric material used for long-term environmental gamma monitoring.

    Science.gov (United States)

    Jones, David F; Paulus, L R

    2008-05-01

    The Idaho Department of Environmental Quality INL Oversight Program (DEQ-INL) operates an environmental gamma radiation detection network consisting of a series of high-pressure ion chambers to provide real-time ambient radiation measurements and a series of passive environmental electret ion chambers to increase coverage area and measure cumulative dose over a calendar quarter. DEQ-INL has identified a consistent over-response of approximately 40% by the electret ion chambers with respect to co-located high-pressure ion chambers since 1998. DEQ-INL conducted a series of three investigations to quantify this over-response. The over-response is likely attributable to a number of factors, including inherent voltage loss by the electret material not due to ionization within the chamber. One aspect of the investigation verified the manufacturer's calibration factor used to convert decrease in voltage to exposure. Additional investigations were performed that identified an average electret voltage loss of 0.2 V d(-1). When this voltage correction was applied to historical environmental data, electret ion chamber response was within 10% of the co-located high-pressure ion chamber response.

  9. Long-term social dynamics drive loss of function in pathogenic bacteria

    DEFF Research Database (Denmark)

    Breum Andersen, Sandra; Marvig, Rasmus Lykke; Molin, Søren

    2015-01-01

    social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find that Pseudomonas aeruginosa bacteria, causing lung......Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly...... in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ....

  10. Modeling the Interest Rate Term Structure: Derivatives Contracts Dynamics and Evaluation

    Directory of Open Access Journals (Sweden)

    Pedro L. Valls Pereira

    2005-06-01

    Full Text Available This article deals with a model for the term structure of interest rates and the valuation of derivative contracts directly dependent on it. The work is of a theoretical nature and deals, exclusively, with continuous time models, making ample use of stochastic calculus results and presents original contributions that we consider relevant to the development of the fixed income market modeling. We develop a new multifactorial model of the term structure of interest rates. The model is based on the decomposition of the yield curve into the factors level, slope, curvature, and the treatment of their collective dynamics. We show that this model may be applied to serve various objectives: analysis of bond price dynamics, valuation of derivative contracts and also market risk management and formulation of operational strategies which is presented in another article.

  11. Stiffening hydrogels to probe short- and long-term cellular responses to dynamic mechanics.

    Science.gov (United States)

    Guvendiren, Murat; Burdick, Jason A

    2012-04-24

    Biological processes are dynamic in nature, and growing evidence suggests that matrix stiffening is particularly decisive during development, wound healing and disease; yet, nearly all in vitro models are static. Here we introduce a step-wise approach, addition then light-mediated crosslinking, to fabricate hydrogels that stiffen (for example, ~3-30 kPa) in the presence of cells, and investigated the short-term (minutes-to-hours) and long-term (days-to-weeks) cell response to dynamic stiffening. When substrates are stiffened, adhered human mesenchymal stem cells increase their area from ~500 to 3,000 μm(2) and exhibit greater traction from ~1 to 10 kPa over a timescale of hours. For longer cultures up to 14 days, human mesenchymal stem cells selectively differentiate based on the period of culture, before or after stiffening, such that adipogenic differentiation is favoured for later stiffening, whereas osteogenic differentiation is favoured for earlier stiffening.

  12. Complex dynamics of osteoclast formation and death in long-term cultures.

    Directory of Open Access Journals (Sweden)

    Timur Akchurin

    Full Text Available BACKGROUND: Osteoclasts, cells responsible for bone resorption, contribute to the development of degenerative, metabolic and neoplastic bone diseases, which are often characterized by persistent changes in bone microenvironment. We aimed to investigate the dynamics of osteoclast formation and death in cultures that considerably exceeded the length of standard protocol and to design a mathematical model describing osteoclastogenesis. METHODOLOGY/PRINCIPAL FINDINGS: RAW 264.7 monocytic cells fuse to form multinucleated osteoclasts upon treatment with pro-resorptive cytokine RANKL. We have found that in long-term experiments (15-26 days, the dynamics of changes in osteoclast numbers was remarkably complex and qualitatively variable in different experiments. Whereas 19 of 46 experiments exhibited single peak of osteoclast formation, in 27 experiments we observed development of successive waves of osteoclast formation and death. Periodic changes in osteoclast numbers were confirmed in long-term cultures of mouse bone marrow cells treated with M-CSF and RANKL. Because the dynamics of changes in osteoclast numbers was found to be largely independent of monocytes, a two-species model of ordinary differential equations describing the changes in osteoclasts and monocytes was ineffective in recapitulating the oscillations in osteoclast numbers. Following experimental observation that medium collected from mature osteoclasts inhibited osteoclastogenesis in fresh cultures, we introduced a third variable, factor f, to describe osteoclast-derived inhibitor. This model allowed us to simulate the oscillatory changes in osteoclasts, which were coupled to oscillatory changes in the factor f, whereas monocytes changed exponentially. Importantly, to achieve the experimentally observed oscillations with increasing amplitude, we also had to assume that osteoclast presence stimulates osteoclast formation. CONCLUSIONS/SIGNIFICANCE: This study identifies the critical

  13. An efficient approach to the evaluation of mid-term dynamic processes in power systems

    Energy Technology Data Exchange (ETDEWEB)

    Zivanovic, R.M. (Pretoria Technikon (South Africa)); Popovic, D.P. (Nikola Tesla Inst., Belgrade (Yugoslavia). Power System Dept.)

    1993-01-01

    This paper presents some improvements in the methodology for analysing mid-term dynamic processes in power systems. These improvements are: an efficient application of the hierarchical clustering algorithm to adaptive identification of coherent generator groups and a significant reduction of the mathematical model, on the basis of monitoring the state of only one generator in one of the established coherent groups. This enables a flexible, simple and fast transformation from the full to the reduced model and vice versa, a significant acceleration of the simulation while keeping the desired accuracy and the automatic use in continual dynamic analysis. Verification of the above mentioned contributions was performed on examples of the dynamic analysis of New England and Yugoslav power systems. (author)

  14. Long-term boreal forest dynamics and disturbances: a multi-proxy approach

    Science.gov (United States)

    Stivrins, Normunds; Aakala, Tuomas; Kuuluvainen, Timo; Pasanen, Leena; Ilvonen, Liisa; Holmström, Lasse; Seppä, Heikki

    2017-04-01

    The boreal forest provides a variety of ecosystem services that are threatened under the ongoing climate warming. Along with the climate, there are several factors (fire, human-impact, pathogens), which influence boreal forest dynamics. Combination of short and long-term studies allowing complex assessment of forest response to natural abiotic and biotic stress factors is necessary for sustainable management of the boreal forest now and in the future. The ongoing EBOR (Ecological history and long-term dynamics of the boreal forest ecosystem) project integrates forest ecological and palaeoecological approaches to study boreal forest dynamics and disturbances. Using pollen, non-pollen palynomorphs, micro- and macrocharcoal, tree rings and fire scars, we analysed forest dynamics at stand-scale by sampling small forest hollows (small paludified depressions) and the surrounding forest stands in Finland and western Russia. Using charcoal data, we estimated a fire return interval of 320 years for the Russian sites, and, based on the fungi Neurospora that can grow on charred tree bark after a low-intensity fire, we were able to distinguish low- and high-intensity fire-events. In addition to the influence of fire events and/or fire regime changes, we further assessed potential relationships between tree species and herbivore presence and pathogens. As an example of such a relationship, our preliminary findings indicated a negative relationship between Picea and fungi Lasiosphaeria (caudata), which occurred during times of Picea decline.

  15. Long-term successional forest dynamics: species and community responses to climatic variability

    Energy Technology Data Exchange (ETDEWEB)

    Kardol, Paul [ORNL; Todd Jr, Donald E [ORNL; Hanson, Paul J [ORNL; Mulholland, Patrick J [ORNL

    2010-01-01

    Question: Are tree dynamics sensitive to climatic variability, and do tree species differ in their responses to climatic variability? Hence, is vulnerability of forest communities to climatic variability depending on stand composition? Location: Mixed young forest at Walker Branch Watershed near Oak Ridge, East-Tennessee, USA. Methods: Using a long-term data set (1967-2006), we analyzed temporal forest dynamics at the tree and species level, and we analyzed community dynamics for forest stands that different in their initial species composition (i.e., Chestnut Oak, Oak-Hickory, Pine, and Yellow poplar stands). Using summer drought and growing season temperature as defined climate drivers, we evaluated relationships between forest dynamics and climate across levels of organization. Results: Over the 4-decade studied period, forest communities underwent successional change and substantially increased their biomass. Variation in summer drought and growing season temperature contributed to temporal biomass dynamics for some tree species, but not for others. Stand-level responses to climatic variability were shown to be related to responses of specific component species; however, not for Pine stands. Pinus echinata, the dominant species in stands initially identified as Pine stands, decreased over time due to periodical outbreaks of the pine bark beetle (Dendroctonus frontalis). The outbreaks on Walker Branch could not be directly related to climatic conditions. Conclusions: Our results imply that vulnerability of developing forests to predicted climate conditions is stand-type dependent, and hence, is a function of species composition. Autogenic successional processes (or insect outbreaks) were found to prevail over climatic variability in determining long-term forest dynamics for stands dominated by sensitive species, emphasizing the importance of studying interactions between forest succession and climate change.

  16. Extended-Term Dynamic Simulations with High Penetrations of Photovoltaic Generation.

    Energy Technology Data Exchange (ETDEWEB)

    Concepcion, Ricky James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Elliott, Ryan Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Donnelly, Matt [Montana Tech., Butte, MT (United States); Sanchez-Gasca, Juan [GE Energy, Schenectady, NY (United States)

    2016-01-01

    The uncontrolled intermittent availability of renewable energy sources makes integration of such devices into today's grid a challenge. Thus, it is imperative that dynamic simulation tools used to analyze power system performance are able to support systems with high amounts of photovoltaic (PV) generation. Additionally, simulation durations expanding beyond minutes into hours must be supported. This report aims to identify the path forward for dynamic simulation tools to accom- modate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for po- tential problems. We present a study of fixed time step, explicit numerical integration schemes that may be more suitable for these goals, based on identified requirements for simulating high PV penetration systems. We also present the alternative of variable time step integration. To help determine the characteristics of systems with high PV generation, we performed small signal sta- bility studies and time domain simulations of two representative systems. Along with feedback from stakeholders and vendors, we identify the current gaps in power system modeling including fast and slow dynamics and propose a new simulation framework to improve our ability to model and simulate longer-term dynamics.

  17. Mapping the structure and dynamics of genomics-related MeSH terms complex networks.

    Science.gov (United States)

    Siqueiros-García, Jesús M; Hernández-Lemus, Enrique; García-Herrera, Rodrigo; Robina-Galatas, Andrea

    2014-01-01

    It has been proposed that the history and evolution of scientific ideas may reflect certain aspects of the underlying socio-cognitive frameworks in which science itself is developing. Systematic analyses of the development of scientific knowledge may help us to construct models of the collective dynamics of science. Aiming at scientific rigor, these models should be built upon solid empirical evidence, analyzed with formal tools leading to ever-improving results that support the related conclusions. Along these lines we studied the dynamics and structure of the development of research in genomics as represented by the entire collection of genomics-related scientific papers contained in the PubMed database. The analyzed corpus consisted in more than 49,000 articles published in the years 1987 (first appearance of the term Genomics) to 2011, categorized by means of the Medical Subheadings (MeSH) content-descriptors. Complex networks were built where two MeSH terms were connected if they are descriptors of the same article(s). The analysis of such networks revealed a complex structure and dynamics that to certain extent resembled small-world networks. The evolution of such networks in time reflected interesting phenomena in the historical development of genomic research, including what seems to be a phase-transition in a period marked by the completion of the first draft of the Human Genome Project. We also found that different disciplinary areas have different dynamic evolution patterns in their MeSH connectivity networks. In the case of areas related to science, changes in topology were somewhat fast while retaining a certain core-structure, whereas in the humanities, the evolution was pretty slow and the structure resulted highly redundant and in the case of technology related issues, the evolution was very fast and the structure remained tree-like with almost no overlapping terms.

  18. Mapping the structure and dynamics of genomics-related MeSH terms complex networks.

    Directory of Open Access Journals (Sweden)

    Jesús M Siqueiros-García

    Full Text Available It has been proposed that the history and evolution of scientific ideas may reflect certain aspects of the underlying socio-cognitive frameworks in which science itself is developing. Systematic analyses of the development of scientific knowledge may help us to construct models of the collective dynamics of science. Aiming at scientific rigor, these models should be built upon solid empirical evidence, analyzed with formal tools leading to ever-improving results that support the related conclusions. Along these lines we studied the dynamics and structure of the development of research in genomics as represented by the entire collection of genomics-related scientific papers contained in the PubMed database. The analyzed corpus consisted in more than 49,000 articles published in the years 1987 (first appearance of the term Genomics to 2011, categorized by means of the Medical Subheadings (MeSH content-descriptors. Complex networks were built where two MeSH terms were connected if they are descriptors of the same article(s. The analysis of such networks revealed a complex structure and dynamics that to certain extent resembled small-world networks. The evolution of such networks in time reflected interesting phenomena in the historical development of genomic research, including what seems to be a phase-transition in a period marked by the completion of the first draft of the Human Genome Project. We also found that different disciplinary areas have different dynamic evolution patterns in their MeSH connectivity networks. In the case of areas related to science, changes in topology were somewhat fast while retaining a certain core-structure, whereas in the humanities, the evolution was pretty slow and the structure resulted highly redundant and in the case of technology related issues, the evolution was very fast and the structure remained tree-like with almost no overlapping terms.

  19. Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction

    Science.gov (United States)

    Lüdemann, L.; Sreenivasa, G.; Michel, R.; Rosner, C.; Plotkin, M.; Felix, R.; Wust, P.; Amthauer, H.

    2006-06-01

    Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 ± 52.0%) and lower partition coefficients (-31.6 ± 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

  20. Influence of precipitation pulses on long-term Prosopis ferox dynamics in the Argentinean intermontane subtropics.

    Science.gov (United States)

    Morales, Mariano S; Villalba, Ricardo

    2012-02-01

    Biological processes in arid communities are associated with episodic precipitation pulses. We postulate that annual to decadal-scale precipitation pulses modulate the dynamics of the intermontane Prepuna woodlands. To study this hypothesis, we have assessed the influence of precipitation pulses on the rates of growth and survival of Prosopis ferox in the Prepuna woodlands during the past century. Tree ages from several P. ferox stands were used to reconstruct the establishment patterns at each sampling site. Ring-width chronologies provided the basis to assess the influence of annual versus multiannual precipitation pulses on radial growth and establishment over time. Both the radial growth and the stand dynamics of P. ferox at the regional scale were found to be largely modulated by climate, with precipitation the dominant factor influencing interannual variations in P. ferox ring-widths. Our analysis of dendrochronological dating data on 885 individuals of P. ferox revealed a period of abundant establishment from the mid-1970s to beginning of 1990 s, which is coincident with an interval of remarkable above-average precipitation. However, tree-growth and establishment patterns at the local scale in the Prepuna also reflected land-use changes, particularly long-term variations in livestock intensity. The P. ferox dynamics documented here substantiates the hierarchical concept of "resource-pulse" in dry ecosystems, with precipitation pulses of different lengths modulating distinct dynamic processes in the P. ferox woodlands. Interannual variations in precipitation influence year-to-year patterns of P. ferox radial growth, whereas multiannual oscillations in rainfall influence episodic events of tree establishment. The long-term interval considered in this study enabled us to disentangle the roles of natural versus human controls on P. ferox dynamics in the region.

  1. Long-term outcome of patients with multiple [corrected] myeloma-related advanced renal failure following auto-SCT.

    Science.gov (United States)

    Glavey, S V; Gertz, M A; Dispenzieri, A; Kumar, S; Buadi, F; Lacy, M; Hayman, S R; Kapoor, P; Dingli, D; McCurdy, A; Hogan, W J; Gastineau, D A; Leung, N

    2013-11-01

    Renal failure commonly complicates multiple myeloma (MM) and is associated with reduced survival. It is not clear whether auto-SCT results in improved renal function or attainment of independence from dialysis in patients with advanced renal impairment due to MM. We conducted a retrospective cohort study of all patients who underwent auto-SCT for MM complicated by advanced renal failure at our institution over a 10-year period (2000-2010). We aimed to assess the association between auto-SCT and renal outcome in patients with serum creatinine (SCr) over 3 mg/dL, attributable to MM, including those who were dialysis dependent. Thirty patients (2.8% of all auto-SCT patients) met inclusion criteria. Fourteen of 15 patients who were dialysis dependent before auto-SCT remained dialysis dependent in the long term despite hematological response (HR). Of the remaining 15 patients with SCr >3 mg/dL, an improvement in glomerular filtration rate (GFR) from 15 to 19.4 mL/min/1.73 m(2) was noted post auto-SCT (P=0.035); however, neither HR post auto-SCT or pre-existing renal function were independently associated with renal outcome. Auto-SCT was not associated with independence from dialysis in patients with renal failure due to MM at our institution. Although auto-SCT was associated with an improvement in GFR in patients with SCr >3 mg/dL, this improvement was not related to HR.

  2. Unclassified Source Term and Radionuclide Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    McCord, John

    2004-08-01

    This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for Central and Western Pahute Mesa: Corrective Action Units (CAUs) 101 and 102.

  3. The effect of nonlinear thermo-fluid-dynamic terms on free-piston Stirling machine stability

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, G. [Univ. of Genoa (Italy). Dipt. di Ingegneria Navale; Monte, F. de [Univ. of L`Aquila (Italy). Dipt. de Energetica

    1996-12-31

    In this work a new linearization technique of the dynamic balance equations of a free-piston Stirling machine is developed. It takes into account the nonlinear thermo-fluid-dynamic terms inherent in the machine, although keeping the linearity of the differential dynamic equations. This allows the equations of motion to be solved still analytically and, therefore, useful algebraic relations (already established by the authors in past studies) linking together the various machine parameters to be used. The advantages related to the proposed linearization methodology are the following: (1) it gives a right interpretation of the machine working when the operational parameters vary, because the considered nonlinear terms have a stabilizing effect; (2) it can be used to predict the machine performance not only with more accuracy, but especially in a more exhaustive way, allowing to estimate also the piston stroke and, therefore, the delivered power; (3) it enables to design the machine in such a way to enhance its stability, thus eliminating the necessity of power control systems.

  4. DMPD: Type I interferon [corrected] gene induction by the interferon regulatory factorfamily of transcription factors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16979567 Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...ng) (.svg) (.html) (.csml) Show Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...orrected] gene induction by the interferon regulatory factorfamily of transcription factors. Authors Honda K

  5. Frontal Theta Dynamics during Response Conflict in Long-Term Mindfulness Meditators.

    Science.gov (United States)

    Jo, Han-Gue; Malinowski, Peter; Schmidt, Stefan

    2017-01-01

    Mindfulness meditators often show greater efficiency in resolving response conflicts than non-meditators. However, the neural mechanisms underlying the improved behavioral efficiency are unclear. Here, we investigated frontal theta dynamics-a neural mechanism involved in cognitive control processes-in long-term mindfulness meditators. The dynamics of EEG theta oscillations (4-8 Hz) recorded over the medial frontal cortex (MFC) were examined in terms of their power (MFC theta power) and their functional connectivity with other brain areas (the MFC-centered theta network). Using a flanker-type paradigm, EEG data were obtained from 22 long-term mindfulness meditators and compared to those from 23 matched controls without meditation experience. Meditators showed more efficient cognitive control after conflicts, evidenced by fewer error responses irrespective of response timing. Furthermore, meditators exhibited enhanced conflict modulations of the MFC-centered theta network shortly before the response, in particular for the functional connection between the MFC and the motor cortex. In contrast, MFC theta power was comparable between groups. These results suggest that the higher behavioral efficiency after conflicts in mindfulness meditators could be a function of increased engagement to control the motor system in association with the MFC-centered theta network.

  6. Climate Effects and Feedback Structure Determining Weed Population Dynamics in a Long-Term Experiment

    Science.gov (United States)

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements. PMID:22272362

  7. Climate effects and feedback structure determining weed population dynamics in a long-term experiment.

    Science.gov (United States)

    Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

    2012-01-01

    Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements.

  8. Climate effects and feedback structure determining weed population dynamics in a long-term experiment.

    Directory of Open Access Journals (Sweden)

    Mauricio Lima

    Full Text Available Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors. Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements.

  9. Short- and long-term variations in non-linear dynamics of heart rate variability

    DEFF Research Database (Denmark)

    Kanters, J K; Højgaard, M V; Agner, E;

    1996-01-01

    OBJECTIVES: The purpose of the study was to investigate the short- and long-term variations in the non-linear dynamics of heart rate variability, and to determine the relationships between conventional time and frequency domain methods and the newer non-linear methods of characterizing heart rate...... variability. METHODS: Twelve healthy subjects were investigated by 3-h ambulatory ECG recordings repeated on 3 separate days. Correlation dimension, non-linear predictability, mean heart rate, and heart rate variability in the time and frequency domains were measured and compared with the results from...... corresponding surrogate time series. RESULTS: A small significant amount of non-linear dynamics exists in heart rate variability. Correlation dimensions and non-linear predictability are relatively specific parameters for each individual examined. The correlation dimension is inversely correlated to the heart...

  10. Long-Term Dynamics and the Orbital Inclinations of the Classical Kuiper Belt Objects

    CERN Document Server

    Kuchner, M J; Holman, M; Kuchner, Marc J.; Brown, Michael E.; Holman, Matthew

    2002-01-01

    We numerically integrated the orbits of 1458 particles in the region of the classical Kuiper Belt (41 AU < a < 47 AU) to explore the role of dynamical instabilities in sculpting the inclination distribution of the classical Kuiper Belt Objects (KBOs). We find that the selective removal of low-inclination objects by overlapping secular resonances (nu_17 and nu_18) acts to raise the mean inclination of the surviving population of particles over 4 billion years of interactions with Jupiter, Saturn, Uranus and Neptune, though these long-term dynamical effects do not themselves appear to explain the discovery of KBOs with inclinations near 30 degrees. Our integrations also imply that after 3 billion years of interaction with the massive planets, high inclination KBOs more efficiently supply Neptune-encountering objects, the likely progenitors of short-period comets, Centaurs, and scattered KBOs. The secular resonances at low inclinations may indirectly cause this effect by weeding out objects unprotected by ...

  11. Modeling short-term dynamics and variability for realistic interactive facial animation.

    Science.gov (United States)

    Stoiber, Nicolas; Breton, Gaspard; Seguier, Renaud

    2010-01-01

    Modern modeling and rendering techniques have produced nearly photorealistic face models, but truly expressive digital faces also require natural-looking movements. Virtual characters in today's applications often display unrealistic facial expressions. Indeed, facial animation with traditional schemes such as keyframing and motion capture demands expertise. Moreover, the traditional schemes aren't adapted to interactive applications that require the real-time generation of context-dependent movements. A new animation system produces realistic expressive facial motion at interactive speed. The system relies on a set of motion models controlling facial-expression dynamics. The models are fitted on captured motion data and therefore retain the dynamic signature of human facial expressions. They also contain a nondeterministic component that ensures the variety of the long-term visual behavior. This system can efficiently animate any synthetic face. The video illustrates interactive use of a system that generates facial-animation sequences.

  12. The Role Of The Aquatic Reservoir In Long-Term Cholera Dynamics

    Science.gov (United States)

    Righetto, L.; Bertuzzo, E.; Mari, L.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2010-12-01

    A novel class of models for Cholera epidemics is described, where the dynamics of the water volume defining the aquatic reservoir of pathogens accessible to a given local community is explicitly considered. In particular, we study how the hydrologic dynamics affects the fluctuations of Vibrio cholerae concentrations in the local reservoir thus driving the evolution of the epidemics at local scales. The novelty of the approach lies in the coupling of an input-output hydrologic dynamics with an epidemiological model which tracks susceptibles, infected and recovered individuals, jointly with bacterial concentrations. Reservoir volumes fluctuating over time indeed control the concentrations of Vibrio cholerae: one of the most common mechanisms of cholera insurgence in endemic regions is, in fact, spring water drought. Here we consider a spatially implicit framework, in order to distinguish the contribution of local dynamics to cholera insurgence at community scales. Our main goal is to investigate the relation between yearly water volume oscillations and long-term trajectories of cholera infection. To this end we take into account a monsoonal fluctuation, with one summer peak in the water input. This simple addition allows us to derive relationships between hydrologic regimes and the epidemiological behavior of the system. Since most of the numerical values of model parameters can be reliably drawn from the literature on the subject, this method allows us to concentrate on significant but still uncertain quantities and associate different ranges of parameter values to different model behaviors which need to be clearly differentiated . Our analysis provides information on the characteristic value of the model parameters for real case studies, comparing simulations and real time series. The model can be very useful in particular for the inference of the intensity of the disease, expressed in terms of the basic reproductive number.

  13. Local competition and metapopulation processes drive long-term seagrass-epiphyte population dynamics.

    Science.gov (United States)

    Lobelle, Delphine; Kenyon, Emma J; Cook, Kevan J; Bull, James C

    2013-01-01

    It is well known that ecological processes such as population regulation and natural enemy interactions potentially occur over a range of spatial scales, and there is a substantial body of literature developing theoretical understanding of the interplay between these processes. However, there are comparatively few studies quantifying the long-term effects of spatial scaling in natural ecosystems. A key challenge is that trophic complexity in real-world biological communities quickly obscures the signal from a focal process. Seagrass meadows provide an excellent opportunity in this respect: in many instances, seagrasses effectively form extensive natural monocultures, in which hypotheses about endogenous dynamics can be formulated and tested. We present amongst the longest unbroken, spatially explict time series of seagrass abundance published to date. Data include annual measures of shoot density, total above-ground abundance, and associated epiphyte cover from five Zostera marina meadows distributed around the Isles of Scilly, UK, from 1996 to 2011. We explore empirical patterns at the local and metapopulation scale using standard time series analysis and develop a simple population dynamic model, testing the hypothesis that both local and metapopulation scale feedback processes are important. We find little evidence of an interaction between scales in seagrass dynamics but that both scales contribute approximately equally to observed local epiphyte abundance. By quantifying the long-term dynamics of seagrass-epiphyte interactions we show how measures of density and extent are both important in establishing baseline information relevant to predicting responses to environmental change and developing management plans. We hope that this study complements existing mechanistic studies of physiology, genetics and productivity in seagrass, whilst highlighting the potential of seagrass as a model ecosystem. More generally, this study provides a rare opportunity to test

  14. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    Science.gov (United States)

    Domaizon, I.; Savichtcheva, O.; Debroas, D.; Arnaud, F.; Villar, C.; Pignol, C.; Alric, B.; Perga, M. E.

    2013-06-01

    While picocyanobacteria (PC) are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes). In particular, we investigated the long-term (100 yr) diversity and dynamics of Synechococcus,, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided the ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction) results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria). The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and the following internally transcribed spacer (ITS). Up to 23 different OTUs (based on 16S rRNA), which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, the study of ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (in temperature and phosphorus concentration) affected Synechococcus, community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus, clusters. Providing such novel insights into the

  15. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    Directory of Open Access Journals (Sweden)

    M. E. Perga

    2013-02-01

    Full Text Available While picocyanobacteria (PC are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes. We particularly investigated the long-term (100 yr diversity and dynamics of Synechococcus, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus (fraction of Synechococcus in total cyanobacteria. The diversity of Synechococcus in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and internal transcribed spacer (ITS. Up to 23 different OTUs (based on 16S rRNA, which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, study of the ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (here, in temperature and phosphorus concentration affected Synechococcus community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus clusters. Providing such novel insights into the long-term history of an important group of

  16. Atomic structure under external confinement: effect of plasma on the spin orbit splitting, relativistic mass correction and Darwin term for hydrogen-like ions

    Science.gov (United States)

    Chaudhuri, Supriya K.; Mukherjee, Prasanta K.; Fricke, Burkhard

    2017-03-01

    The effect of Debye and quantum plasma environment on the structural properties such as spin orbit splitting, relativistic mass correction and Darwin term for a few iso-electronic members of hydrogen viz. C5 +, O7 +, Ne9 +, Mg11 +, Si13 +, S15 +, Ar17 +, Ca19 + and Ti21 + has been analysed systematically for the first time for a range of coupling strengths of the plasma. The Debye plasma environment has been treated under a standard screened Coulomb potential (SCP) while the quantum plasma has been treated under an exponential cosine screened Coulomb potential (ECSCP). Estimation of the spin orbit splitting under SCP and ECSCP plasma is restricted to the lowest two dipole allowed states while for the other two properties, the ground state as well as the first two excited states have been chosen. Calculations have been extended to nuclear charges for which appreciable relativistic corrections are noted. In all cases calculations have been extended up to such screening parameters for which the respective excitation energies tend towards their stability limit determined by the ionisation potential at that screening parameter. Interesting behavior of the respective properties with respect to the plasma coupling strength has been noted.

  17. Effects of long-term hormone replacement therapy on QT and corrected QT dispersion during resting and peak exercise electrocardiography in post-menopausal women.

    Science.gov (United States)

    Altunkeser, Bülent B; Ozdemir, Kurtulus; Içli, Abdullah; Celik, Cetin; Akyürek, Cemalettin; Gök, Hasan

    2002-01-01

    It is known that the QT interval is longer in women than men. Estrogen is reported to account for the QT interval prolongation in several studies conducted with hormone replacement therapy (HRT) in postmenopausal women. Along with this, there are conflicting data as regards the effects of HRT on QT interval and dispersion. Moreover, there is no evidence about the effect of HRT on exercise QT parameters. We compared QT parameters obtained from surface electrocardiograms during resting and peak exercise before and after 6 months of HRT consisting of estrogen plus progesterone in healthy postmenopausal women. Twenty-four healthy postmenopausal women were given 0.625 mg/day conjugated estrogens and 2.5 mg/day medroxyprogesterone acetate for 6 months. Exercise stress testing using the Bruce protocol was performed before and after HRT. QT maximum, minimum, dispersion and corrected QT maximum, minimum and dispersion were calculated during resting and peak exercise. HRT resulted in a significant increase in estradiol plasma levels from 24+/-10 pg/mL to 117+/-66 pg/mL (Pexercise (20+/-7 versus 25+/-10 ms; Pexercise QT parameters were unchanged. The resting QT parameters are not affected by long term HRT consisting of estrogen plus progesterone, which leads to an increase in QT dispersion and corrected QT dispersion during peak exercise.

  18. Investigations on control algorithm of steady-state cornering and control strategy for dynamical correction in a steer-by-wire system

    Institute of Scientific and Technical Information of China (English)

    Ying XU; Chang-fu ZONG; Hsiao-hsiang NA; Lei LIU

    2009-01-01

    To improve the handling performance of a steer-by-wire (SBW) vehicle, a series of control logics are proposed. Firstly,an algorithm for enhancing the maneuvering in steady-state cornering is presented. On this basis, two categories of control strategies are used to dynamically correct and compensate the transient state steering responses and vehicle behaviors. Simulator tests including subjective evaluations and virtual field tests are both conducted to make comprehensive investigations on the series of control logics. The subjective evaluations demonstrate that the SBW vehicle with a specifically selected value of steering sensitivity tends to be more desirable for driving than a conventional one in which a fixed steering ratio exists. The virtual field tests indicate that the control strategies for dynamical correction and compensation could effectively improve the handling performances of an SBW vehicle by reducing the work load of drivers, enhancing the track-holding performance, and improving steering response properties.

  19. Short-Term Plasticity of a Thalamocortical Pathway Dynamically Modulated by Behavioral State

    Science.gov (United States)

    Castro-Alamancos, Manuel A.; Connors, Barry W.

    1996-04-01

    The neocortex receives information about the environment and the rest of the brain through pathways from the thalamus. These pathways have frequency-dependent properties that can strongly influence their effect on the neocortex. In 1943 Morison and Dempsey described "augmenting responses," a form of short-term plasticity in some thalamocortical pathways that is triggered by 8- to 15-hertz activation. Results from anesthetized rats showed that the augmenting response is initiated by pyramidal cells in layer V. The augmenting response was also observed in awake, unrestrained animals and was found to be dynamically modulated by their behavioral state.

  20. An exact representation of the fermion dynamics in terms of Poisson processes

    CERN Document Server

    Beccaria, M; De Angelis, G F; Jona-Lasinio, G; Beccaria, Matteo; Presilla, Carlo; Angelis, Gian Fabrizio De; Jona-Lasinio, Giovanni

    1999-01-01

    We present a simple derivation of a Feynman-Kac type formula to study fermionic systems. In this approach the real time or the imaginary time dynamics is expressed in terms of the evolution of a collection of Poisson processes. A computer implementation of this formula leads to a family of algorithms parametrized by the values of the jump rates of the Poisson processes. From these an optimal algorithm can be chosen which coincides with the Green Function Monte Carlo (GFMC) method in the limit when the latter becomes exact.

  1. Regulatory competence and social communication in term and preterm infants at 12 months corrected age. Results from a randomized controlled trial.

    Science.gov (United States)

    Olafsen, Kåre S; Rønning, John A; Handegård, Bjørn Helge; Ulvund, Stein Erik; Dahl, Lauritz Bredrup; Kaaresen, Per Ivar

    2012-02-01

    Temperamental regulatory competence and social communication in term and preterm infants at 12 months corrected age was studied in a randomized controlled intervention trial aimed at enhancing maternal sensitive responsiveness. Surviving infants competence was measured with the Infant Behavior Questionnaire, and social communication with the Early Social Communication Scales. Preterm intervention infants with low regulatory competence had higher responding to joint attention than preterm control infants. A sensitizing intervention may moderate the association between temperament and social communication, and thus allow an alternative functional outlet for preterm infants low in regulatory competence. The finding may have implications for conceptualizations of the role of early sensitizing interventions in promoting important developmental outcomes for premature infants. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Dynamic stability of communities of amphibians in short-term-flooded forest ecosystems

    Directory of Open Access Journals (Sweden)

    O. V. Zhukov

    2015-09-01

    Full Text Available The estimation of stability of amphibian populations on the basis of data of population dynamics is given. The paper shows an attempt to estimate the direction of dynamic changes of amphibian populations, and defines the rate of the system deviation from the stationary state due to possible influence of the environmental factors by using concepts such as reactivity, degree of reactivity and flexibility of the system when using their indexes. It is found that populations of amphibians are quite stable with regard to quantifying these species. Characteristic feature is the elasticity of the system. It is confirmed by the elasticity of the system species Bufo bufo (Linnaeus, 1758. TypePelobates fuscus (Laurenti, 1768 is defined as a factor of stability of the system in quantitative terms. Dependenceof dynamics of the population on its size is established using the regression equation. Dynamics of groups depends on the action of possible predictors in response to which the population of B. bufo is not changed. The ecosystem is characterized as a place of interaction between biotic factors and factors of abiotic origin, which are due to the external action. Internal factor of the ecosystem stability is the influence of some amphibian populations on the other ones. The system features sustainable and relatively stable number of B. bufo, which does not affect the level of its stability. Stationary state of the grouping is unstable due to dynamic matrix, which describes the behavior of the group in the vicinity of the first stationary state. The second steady state is stableone, and the system returns to the stationary state with the help of wave-like dynamics. On the basis of our study it is established that the number of groups of amphibians remains stable, the systems behave differently, and dynamics of their return to the stationary state is elastic or reactive one. Еcosystems within lime-ash oak forests in the Central floodplain of the Samarariver

  3. Long-term memory contribution as applied to the motion of discrete dynamical systems

    Science.gov (United States)

    Stanislavsky, A. A.

    2006-12-01

    We consider the evolution of logistic maps under long-term memory. The memory effects are characterized by one parameter, α. If it equals to zero, any memory is absent. This leads to the ordinary discrete dynamical systems. For α =1 the memory becomes full, and each subsequent state of the corresponding discrete system accumulates all past states with the same weight just as the ordinary integral of first order does in the continuous space. The case with 0fractional integral depending on time, and the parameter α is equivalent to the order index of the fractional integral. We study the evolution of the bifurcation diagram among α =0 and α =0.15. The main result of this work is that the long-term memory effects make difficulties for developing the chaos motion in such logistic maps. The parameter α resembles a governing parameter for the bifurcation diagram. For α >0.15 the memory effects win over chaos.

  4. Can the dynamics of the term structure of petroleum futures be forecasted? Evidence from major markets

    Energy Technology Data Exchange (ETDEWEB)

    Skiadopoulos, George [University of Piraeus, Department of Banking and Financial Management (Greece); Financial Options Research Centre, Warwick Business School, University of Warwick (United Kingdom); Chantziara, Thalia

    2008-05-15

    We investigate whether the daily evolution of the term structure of petroleum futures can be forecasted. To this end, the principal components analysis is employed. The retained principal components describe the dynamics of the term structure of futures prices parsimoniously and are used to forecast the subsequent daily changes of futures prices. Data on the New York Mercantile Exchange (NYMEX) crude oil, heating oil, gasoline, and the International Petroleum Exchange (IPE) crude oil futures are used. We find that the retained principal components have small forecasting power both in-sample and out-of-sample. Similar results are obtained from standard univariate and vector autoregression models. Spillover effects between the four petroleum futures markets are also detected. (author)

  5. Limitless capacity: A dynamic object-oriented approach to short-term memory

    Directory of Open Access Journals (Sweden)

    Bill eMacken

    2015-03-01

    Full Text Available The notion of capacity-limited processing systems is a core element of cognitive accounts of limited and variable performance, enshrined within the short-term memory construct. We begin with a detailed critical analysis of the conceptual bases of this view and argue that there are fundamental problems – ones that go to the heart of cognitivism more generally – that render it untenable. In place of limited capacity systems, we propose a framework for explaining performance that focuses on the dynamic interplay of three aspects of any given setting: the particular task that must be accomplished, the nature and form of the material upon which the task must be performed, and the repertoire of skills and perceptual-motor functions possessed by the participant. We provide empirical examples of the applications of this framework in areas of performance typically accounted for by reference to capacity-limited short-term memory processes.

  6. Limitless capacity: a dynamic object-oriented approach to short-term memory.

    Science.gov (United States)

    Macken, Bill; Taylor, John; Jones, Dylan

    2015-01-01

    The notion of capacity-limited processing systems is a core element of cognitive accounts of limited and variable performance, enshrined within the short-term memory construct. We begin with a detailed critical analysis of the conceptual bases of this view and argue that there are fundamental problems - ones that go to the heart of cognitivism more generally - that render it untenable. In place of limited capacity systems, we propose a framework for explaining performance that focuses on the dynamic interplay of three aspects of any given setting: the particular task that must be accomplished, the nature and form of the material upon which the task must be performed, and the repertoire of skills and perceptual-motor functions possessed by the participant. We provide empirical examples of the applications of this framework in areas of performance typically accounted for by reference to capacity-limited short-term memory processes.

  7. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping

    2014-10-01

    Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase

  8. Mechanism for Corrective Action on Budget Imbalances

    Directory of Open Access Journals (Sweden)

    Ion Lucian CATRINA

    2014-02-01

    Full Text Available The European Fiscal Compact sets the obligation for the signatory states to establish an automatic mechanism for taking corrective action on budget imbalances. Nevertheless, the European Treaty says nothing about the tools that should be used in order to reach the desired equilibrium of budgets, but only that it should aim at correcting deviations from the medium-term objective or the adjustment path, including their cumulated impact on government debt dynamics. This paper is aiming at showing that each member state has to build the correction mechanism according to the impact of the chosen tools on economic growth and on general government revenues. We will also emphasize that the correction mechanism should be built not only exacerbating the corrective action through spending/ tax based adjustments, but on a high quality package of economic policies as well.

  9. Subsurface ecosystem resilience: long-term attenuation of subsurface contaminants supports a dynamic microbial community

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, J.M.; Neuhauser, E.F.; Ripp, J.A.; Mauro, D.M.; Madsen, E.L. [Cornell University, Ithaca, NY (United States). Dept. of Microbiology

    2010-01-15

    The propensity for groundwater ecosystems to recover from contamination by organic chemicals (in this case, coal-tar waste) is of vital concern for scientists and engineers who manage polluted sites. The microbially mediated cleanup processes are also of interest to ecologists because they are an important mechanism for the resilience of ecosystems. In this study we establish the long-term dynamic nature of a coal-tar waste-contaminated site and its microbial community. We present 16 years of chemical monitoring data, tracking responses of a groundwater ecosystem to organic contamination (naphthalene, xylenes, toluene, 2-methyl naphthalene and acenaphthylene) associated with coal-tar waste. In addition, we analyzed small-subunit (SSU) ribosomal RNA (rRNA) genes from two contaminated wells at multiple time points over a 2-year period. Principle component analysis of community rRNA fingerprints (terminal-restriction fragment length polymorphism (T-RFLP)) showed that the composition of native microbial communities varied temporally, yet remained distinctive from well to well. After screening and analysis of 1178 cloned SSU rRNA genes from Bacteria, Archaea and Eukarya, we discovered that the site supports a robust variety of eukaryotes (for example, alveolates (especially anaerobic and predatory ciliates), stramenopiles, fungi, even the small metazoan flatworm, Suomina) that are absent from an uncontaminated control well. This study links the dynamic microbial composition of a contaminated site with the long-term attenuation of its subsurface contaminants.

  10. Long-term morpho-dynamics in special type of estuary

    Institute of Scientific and Technical Information of China (English)

    吴超羽; 周蒂

    2001-01-01

    Thousands of rocky hills and islands scattered in the Pearl River delta plain and the adjacent coastal waters in South China have been or will be acted as deposition nucleus during the evolution process of the delta. The Huangmaohai estuarine complex consists of two of the eight major outlets of the Pearl River estuarine system. Since sea level reached the present level approximately 6000 years ago, especially in the last 250 years, the Huangmaohai estuarine complex has progressed to the sea by filling up the sea inlets formed between these rocky islands and between mainland and islands. This ’filling up’ process left deep imprints on the long-term mor-pho-dynamic equilibrium in the estuaries. The present paper reveals that the long-term mor-pho-dynamic relation originating from this ’filling up’ process in the Huangmaohai estuarine complex is different from that in many coastal plain estuaries in several aspects: (1) longitudinal variation of estuary width, (2) longitudinal variation of tidal range, (3)

  11. Computation of methodology-independent single-ion solvation properties from molecular simulations. III. Correction terms for the solvation free energies, enthalpies, entropies, heat capacities, volumes, compressibilities, and expansivities of solvated ions.

    Science.gov (United States)

    Reif, Maria M; Hünenberger, Philippe H

    2011-04-14

    The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions (finite or periodic system, system or box size) and treatment of electrostatic interactions (Coulombic, lattice-sum, or cutoff-based) used during these simulations. However, as shown by Kastenholz and Hünenberger [J. Chem. Phys. 124, 224501 (2006)], correction terms can be derived for the effects of: (A) an incorrect solvent polarization around the ion and an incomplete or/and inexact interaction of the ion with the polarized solvent due to the use of an approximate (not strictly Coulombic) electrostatic scheme; (B) the finite-size or artificial periodicity of the simulated system; (C) an improper summation scheme to evaluate the potential at the ion site, and the possible presence of a polarized air-liquid interface or of a constraint of vanishing average electrostatic potential in the simulated system; and (D) an inaccurate dielectric permittivity of the employed solvent model. Comparison with standard experimental data also requires the inclusion of appropriate cavity-formation and standard-state correction terms. In the present study, this correction scheme is extended by: (i) providing simple approximate analytical expressions (empirically-fitted) for the correction terms that were evaluated numerically in the above scheme (continuum-electrostatics calculations); (ii) providing correction terms for derivative thermodynamic single-ion solvation properties (and corresponding partial molar variables in solution), namely, the enthalpy, entropy, isobaric heat capacity, volume, isothermal compressibility, and isobaric expansivity (including appropriate standard-state correction terms). The ability of the correction scheme to produce methodology-independent single-ion solvation free energies based on atomistic simulations is tested in the case of Na(+) hydration, and the nature and magnitude of the correction terms for

  12. Dynamical prediction and pattern mapping in short-term load forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Luis Antonio; Rodrigues, Daniela D.; Lima, Silvio T. [Departamento de Engenharia Eletronica, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG (Brazil); Martinez, Carlos Barreira [Departamento de Engenharia Hidraulica e Recursos Hidricos, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG (Brazil)

    2008-01-15

    This work will not put forward yet another scheme for short-term load forecasting but rather will provide evidences that may improve our understanding about fundamental issues which underlay load forecasting problems. In particular, load forecasting will be decomposed into two main problems, namely dynamical prediction and pattern mapping. It is argued that whereas the latter is essentially static and becomes nonlinear when weekly features in the data are taken into account, the former might not be deterministic at all. In such cases there is no determinism (serial correlations) in the data apart from the average cycle and the best a model can do is to perform pattern mapping. Moreover, when there is determinism in addition to the average cycle, the underlying dynamics are sometimes linear, in which case there is no need to resort to nonlinear models to perform dynamical prediction. Such conclusions were confirmed using real load data and surrogate data analysis. In a sense, the paper details and organizes some general beliefs found in the literature on load forecasting. This sheds some light on real model-building and forecasting problems and helps understand some apparently conflicting results reported in the literature. (author)

  13. Soil Organic Matter Dynamics in the Rothamsted Long-term Experiments

    Science.gov (United States)

    MacDonald, A.; Poulton, P.

    2009-04-01

    Soil science research at Rothamsted dates from 1843 when John Bennet Lawes and Joseph Henry Gilbert started the first of a series of what became long-term field experiments. The main object of these experiments was to examine the effect of inorganic and organic fertilisers and manures on crop yield and soil fertility. These "Classical Field Experiments" included studies on winter wheat (Broadbalk 1843), spring barley (Hoos Barley 1852) and permanent grassland (Park Grass 1856). Additional experiments were established in the 20th century to examine the value of ley-arable cropping, including the Highfield and Fosters Ley-arable experiments (1948) and the Woburn Ley-arable experiment (1938). More recently, the effects of incorporating organic manures and cereal straw have been examined. Early results quickly showed the benefits of inorganic N and P fertilisers on crop production, but the effects of contrasting land uses and management practices on soil properties emerged more slowly. Measurements of soil organic carbon (C) and nitrogen (N) in soils taken at intervals from the long-term experiments indicate that the rate of soil organic matter (SOM) accumulation is controlled largely by the balance between the rate of organic matter inputs and its oxidation rate, and that these are strongly influenced by land use and management, soil texture (especially clay content) and climate. A recent examination of soil organic C data from two long-term grassland experiments in the UK (including Park Grass) indicates that any changes observed in soil organic C under long-term grasslands over the past 40 years are more likely to be due to changes in land use and management rather than climate change. Data from the Rothamsted Long-term experiments have been used to develop and test biogeochemical models of C and N dynamics. In particular, the Roth-C model has successfully simulated soil C dynamics in the long-term experiments at Rothamsted and elsewhere. This model uses several

  14. [Degradation dynamics of POPs atrazine in soils under long-term located fertilization conditions].

    Science.gov (United States)

    Wang, Jun; Zhu, Lu-sheng; Xie, Hui; Song, Yan; Sun, Rui-lian; Zhang, Fu-dao

    2007-12-01

    To evaluate the difference of POPs atrazine degradation dynamics in soils under different fertilization conditions, we set up an analysis method of the atrazine residue in soils and studied residue dynamics of atrazine in soils under a long-term located fertilization conditions. After extracted by surging with acetone, liquid-liquid partition and eluted through florisil, the residue of atrazine in soils was detected by gas chromatogram with 63Ni-ECD. The minimum detectable quantity of atrazine is 6.4 x 10(-12) g and the minimum detectable concentration is 6.4 x 10(-9) g x kg(-1) in the soil. The spiked recoveries of atrazine with the three concentration of 0.11, 1.1, 11.0 mg x kg(-1) in soils are 91.41% +/- 4.36%, 93.58% +/- 4.54%, 90.35% +/- 3.59%, according with the request of pesticide residue analysis. The degradation of atrazine in soil under a long-term located fertilization conditions was studied. The results show the degradation of atrazine follows stair dynamic equation, and the degradation half-life of atrazine in soils fertilized with CK, NPK, NPK + M, NPK + S are 20.6, 23.0, 28.5, 33.2 d, respectively. Subjected to analysis of LSR, NPK and organic fertilizers are obviously propitious to the degradation of atrazine. The separate regression and stepwise regression analysis prove the degradation half-life of atrazine in soils is well related with the content of alkaline nitrogen, organic matter and total nitrogen, and the coefficients are 0.9983, 0.9826 and 0.9521, respectively. Maybe the reason is that these soil nutrient substance offers enough the element carbon and nitrogen for action of microbe, and the higher action of microbe quickens the degradation of atrazine in soils.

  15. STUDY OF UNCONVENTIONAL TEXTILES USED AS INSERTION FOR CLOTHES IN TERMS OF ITS DYNAMIC TENSILE STREGHT

    Directory of Open Access Journals (Sweden)

    OANA Dorina

    2015-05-01

    Full Text Available Unconventional textiles are manufactured different from those obtained by the classic spinning weaving and knitting. They are obtained by mechanical or chemical consolidation of a textile backing up of fibrous layers or combinations of layers of fiber and yarn, fabrics and yarns, fabrics or knitted fabrics and fibers. For the apparel industry has expanded the use of unconventional fabrics especially in auxiliary materials they replace traditional materials such as woven tassel and buckram. Application of reinforcement layers have very important role in increasing the stability of form and material exploitation basic characteristics. Using unconventional fabrics used as insertions for clothing presents a desosibit advantage in terms of possible replacement joints bonded by heat sealed seam, thus saving time and using technology more accessible. For unconventional fabrics used as auxiliaries in the apparel industry is usually determined flexural stiffness, tensile strength, resistance to repeated stretches but more efficient in terms of proximity to the real conditions of the clothing is dynamic tensile resistance. Unconventional textile materials have a certain anisotropy in terms of the performed measurements. So, we followed the conducted research to highlight the anisotropy of several samples and characterization of best of unconventional materials in this regard, to be used under conditions effective as clothing industry.

  16. Frontal Theta Dynamics during Response Conflict in Long-Term Mindfulness Meditators

    Science.gov (United States)

    Jo, Han-Gue; Malinowski, Peter; Schmidt, Stefan

    2017-01-01

    Mindfulness meditators often show greater efficiency in resolving response conflicts than non-meditators. However, the neural mechanisms underlying the improved behavioral efficiency are unclear. Here, we investigated frontal theta dynamics—a neural mechanism involved in cognitive control processes—in long-term mindfulness meditators. The dynamics of EEG theta oscillations (4–8 Hz) recorded over the medial frontal cortex (MFC) were examined in terms of their power (MFC theta power) and their functional connectivity with other brain areas (the MFC-centered theta network). Using a flanker-type paradigm, EEG data were obtained from 22 long-term mindfulness meditators and compared to those from 23 matched controls without meditation experience. Meditators showed more efficient cognitive control after conflicts, evidenced by fewer error responses irrespective of response timing. Furthermore, meditators exhibited enhanced conflict modulations of the MFC-centered theta network shortly before the response, in particular for the functional connection between the MFC and the motor cortex. In contrast, MFC theta power was comparable between groups. These results suggest that the higher behavioral efficiency after conflicts in mindfulness meditators could be a function of increased engagement to control the motor system in association with the MFC-centered theta network. PMID:28638334

  17. Long-term spatio-temporal dynamics of the mosquito Aedes aegypti in temperate Argentina.

    Science.gov (United States)

    Fischer, S; De Majo, M S; Quiroga, L; Paez, M; Schweigmann, N

    2017-04-01

    Buenos Aires city is located near the southern limit of the distribution of Aedes aegypti (Diptera: Culicidae). This study aimed to assess long-term variations in the abundance of Ae. aegypti in Buenos Aires in relation to changes in climatic conditions. Ae. aegypti weekly oviposition activity was analyzed and compared through nine warm seasons from 1998 to 2014, with 200 ovitraps placed across the whole extension of the city. The temporal and spatial dynamics of abundances were compared among seasons, and their relation with climatic variables were analyzed. Results showed a trend to higher peak abundances, a higher number of infested sites, and longer duration of the oviposition season through subsequent years, consistent with a long-term colonization process. In contrast, thermal favorability and rainfall pattern did not show a consistent trend of changes. The long-term increase in abundance, and the recently documented expansion of Ae. aegypti to colder areas of Buenos Aires province suggest that local populations might be adapting to lower temperature conditions. The steadily increasing abundances may have implications on the risk of dengue transmission.

  18. Dynamic analysis of long-term seismicity effects on the Piz Dora DSGSD (E Switzerland)

    Science.gov (United States)

    Riva, Federico; Agliardi, Federico; Battista Crosta, Giovanni; Zanchi, Andrea; Scotti, Riccardo

    2016-04-01

    validate a series of continuum 2D FEM dynamic simulations, set up starting from the signal characterization of a real earthquake occurred in 1999 few kilometers from the slope in a similar litho-structural seismo-tectonic setting. Available seismic hazard maps were used to scale in terms of PGA the dynamic input and describe events with specified return time. These were applied at the model base before, during and after slope deglaciation history, constrained by relative post-LGM paleoclimatic evidence. Comparison between static and dynamic simulations suggests a notable contribution of repeated seismic events to strain accumulation in different slope sectors, promoting the onset of DSGSD in marginally stable deglaciating alpine rock slopes.

  19. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    Directory of Open Access Journals (Sweden)

    I. Domaizon

    2013-06-01

    Full Text Available While picocyanobacteria (PC are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes. In particular, we investigated the long-term (100 yr diversity and dynamics of Synechococcus,, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided the ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria. The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and the following internally transcribed spacer (ITS. Up to 23 different OTUs (based on 16S rRNA, which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, the study of ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (in temperature and phosphorus concentration affected Synechococcus, community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus, clusters. Providing such novel

  20. Long-term dynamics of adaptive evolution in a globally important phytoplankton species to ocean acidification

    Science.gov (United States)

    Schlüter, Lothar; Lohbeck, Kai T.; Gröger, Joachim P.; Riebesell, Ulf; Reusch, Thorsten B. H.

    2016-01-01

    Marine phytoplankton may adapt to ocean change, such as acidification or warming, because of their large population sizes and short generation times. Long-term adaptation to novel environments is a dynamic process, and phenotypic change can take place thousands of generations after exposure to novel conditions. We conducted a long-term evolution experiment (4 years = 2100 generations), starting with a single clone of the abundant and widespread coccolithophore Emiliania huxleyi exposed to three different CO2 levels simulating ocean acidification (OA). Growth rates as a proxy for Darwinian fitness increased only moderately under both levels of OA [+3.4% and +4.8%, respectively, at 1100 and 2200 μatm partial pressure of CO2 (Pco2)] relative to control treatments (ambient CO2, 400 μatm). Long-term adaptation to OA was complex, and initial phenotypic responses of ecologically important traits were later reverted. The biogeochemically important trait of calcification, in particular, that had initially been restored within the first year of evolution was later reduced to levels lower than the performance of nonadapted populations under OA. Calcification was not constitutively lost but returned to control treatment levels when high CO2–adapted isolates were transferred back to present-day control CO2 conditions. Selection under elevated CO2 exacerbated a general decrease of cell sizes under long-term laboratory evolution. Our results show that phytoplankton may evolve complex phenotypic plasticity that can affect biogeochemically important traits, such as calcification. Adaptive evolution may play out over longer time scales (>1 year) in an unforeseen way under future ocean conditions that cannot be predicted from initial adaptation responses. PMID:27419227

  1. Dynamics of Hippocampal Protein Expression During Long-term Spatial Memory Formation.

    Science.gov (United States)

    Borovok, Natalia; Nesher, Elimelech; Levin, Yishai; Reichenstein, Michal; Pinhasov, Albert; Michaelevski, Izhak

    2016-02-01

    Spatial memory depends on the hippocampus, which is particularly vulnerable to aging. This vulnerability has implications for the impairment of navigation capacities in older people, who may show a marked drop in performance of spatial tasks with advancing age. Contemporary understanding of long-term memory formation relies on molecular mechanisms underlying long-term synaptic plasticity. With memory acquisition, activity-dependent changes occurring in synapses initiate multiple signal transduction pathways enhancing protein turnover. This enhancement facilitates de novo synthesis of plasticity related proteins, crucial factors for establishing persistent long-term synaptic plasticity and forming memory engrams. Extensive studies have been performed to elucidate molecular mechanisms of memory traces formation; however, the identity of plasticity related proteins is still evasive. In this study, we investigated protein turnover in mouse hippocampus during long-term spatial memory formation using the reference memory version of radial arm maze (RAM) paradigm. We identified 1592 proteins, which exhibited a complex picture of expression changes during spatial memory formation. Variable linear decomposition reduced significantly data dimensionality and enriched three principal factors responsible for variance of memory-related protein levels at (1) the initial phase of memory acquisition (165 proteins), (2) during the steep learning improvement (148 proteins), and (3) the final phase of the learning curve (123 proteins). Gene ontology and signaling pathways analysis revealed a clear correlation between memory improvement and learning phase-curbed expression profiles of proteins belonging to specific functional categories. We found differential enrichment of (1) neurotrophic factors signaling pathways, proteins regulating synaptic transmission, and actin microfilament during the first day of the learning curve; (2) transcription and translation machinery, protein

  2. Long-Term Engagement with Health-Management Technology: a Dynamic Process in Diabetes.

    Science.gov (United States)

    Klasnja, Predrag; Kendall, Logan; Pratt, Wanda; Blondon, Katherine

    2015-01-01

    Diabetes management is a complex, dynamic process that is largely incumbent on patient choices and behavior. We explore how health-management needs-and the needs for technological support-change over time for individuals with diabetes. Through interviews and a focus group, we found that after initial diagnosis, individuals face acute information needs and chiefly turn to mobile applications and Internet resources to help understand the diabetes-specific factors that affect their health. Over time their focus shifts from highly regimented routines to more flexible ones that enable them to maintain a quality of life. Our results suggest that long-term engagement with health technology does not necessarily require continuous, sustained use: routine disease management could lead to a decrease in use, until a new event occurs. Our findings point to a need for tools that help patients with diabetes to effectively manage their health as their bodies, treatment and circumstances change over time.

  3. Dynamical Generation of mu-terms and Yukawa Couplings in Intersecting D-brane Models

    CERN Document Server

    Kitazawa, N

    2004-01-01

    We construct a supersymmetric composite model from type IIA T^6/(Z_2 x Z_2) orientifolds with intersecting D6-branes. All the three generations of quarks and leptons are naturally emerged as composite fields at low energies. Two pairs of light electroweak Higgs doublets can be obtained with realistic values of mu-terms. The hierarchical Yukawa couplings for the quark-lepton mass can be generated by the interplay between the string-level higher dimensional interactions among "preons" and the dynamics of the confinement of "preons". The model is not perfectly realistic in some points: some exotic particles, one additional U(1) gauge symmetry, no explicit mechanism for supersymmetry breaking, and so on.

  4. Investigation of Vegetation Dynamics using Long-Term Normalized Difference Vegetation Index Time-Series

    Directory of Open Access Journals (Sweden)

    Tamara Bellone

    2009-01-01

    Full Text Available Problem statement: The Normalized Difference Vegetation Index (NDVI is the most extensively used satellite-derived index of vegetation health and density. Since climate is one of the most important factors affecting vegetation condition, satellite-derived vegetation indexes have been often used to evaluate climatic and environmental changes at regional and global scale. The proposed study attempted to investigate the temporal vegetation dynamics in the whole Africa using historical NDVI time-series. Approach: For this aim, 15 day maximum value NDVI composites at 8 km spatial resolution produced from the NASA Global Inventory Mapping and Monitoring System (GIMMS had been used. They were derived from data collected daily by NOAA AVHRR satellites. The AVHRR NDVI GIMMS dataset was freely available and gives global coverage over an extensive time period. First of all, the selected NDVI base data had been geometrically pre-processed and organized into a historical database implemented in order to grant their spatial integration. Starting from this archive, monthly and yearly NDVI historical time-series, extended from 1982-2006, had been then developed and analysed on a pixel basis. Several routines hade been developed in IDL (Interactive Data Language programming tool with the purpose of applying suitable statistical analysis techniques to the historical information in the database in order to identify the long-term trend components of generated NDVI time-series and extract vegetation dynamics. Specific tests had been then considered in order to define the validity of results. Results: The existence of clear regional trends of NDVI, both decreasing and increasing had been showed, which helped to highlight areas subject, respectively to reduction or increase in vegetation greenness. Conclusion: As the relationship between the NDVI and vegetation productivity was well established, these estimated long-term trend components may be also, with much more

  5. Development of novel short-term heating angioplasty: thermal denaturation dynamics of collagen in artery wall

    Science.gov (United States)

    Shimazaki, N.; Tokunaga, H.; Katou, Y.; Hayashi, T.; Arai, T.

    2009-02-01

    We have studied to develop the new thermal angioplasty methodology, photo-thermo dynamic balloon angioplasty (PTDBA), which provides artery dilatation with short-term (collagen in artery media may be the important factor to attain sufficient artery dilatation for the PTDBA. In order to predict the optimum heating condition i.e. the balloon temperature and heating duration, we investigated the thermal denaturation dynamics of artery collagen in ex vivo. The extracted fresh porcine carotid artery was used. The temperature-dependent light scattering property and mechanical property of the artery specimen were simultaneously measured during artery temperature rising by specially made setup to assess the denaturation of arterial collagen. The change rate of the backscattered light intensity from the artery specimen; I(T)/I0 with 633nm was measured to evaluate the artery scattering property change with the thermal denaturation. The artery specimen was heated from 25°C to 80°C with constant temperature rising rate of 3°C/min. The measured I(T)/I0 was suddenly increased over 48°C. This boundary temperature might be the initiation temperature of the arterial collagen denaturation. We defined the variation of the I(T)/I0 as the collagen denaturation ratio, and calculated the reactive enthalpy by the chemical equilibrium theory. Since the calculated enthalpy was similar to the enthalpy in literature report, the variety of I(T)/I0 during the temperature rising might be attributed to the collagen conformational change due to the denaturation. In terms of the artery internal force measurement, the artery force was decreased with increasing of the artery temperature up to 65°C (i.e. softening), and increased over 65°C (i.e. shrinkage). We confirmed that the changes of the backscattered light (at 633nm in wavelength) from the artery might represent the artery collagen thermal denaturation degree.

  6. A wearable wireless ECG monitoring system with dynamic transmission power control for long-term homecare.

    Science.gov (United States)

    Wang, Yishan; Doleschel, Sammy; Wunderlich, Ralf; Heinen, Stefan

    2015-03-01

    This paper presents a wearable wireless ECG monitoring system based on novel 3-Lead electrode placements for long-term homecare. The experiment for novel 3-Lead electrode placements is carried out, and the results show that the distance between limb electrodes can be significantly reduced. Based on the new electrode position, a small size sensor node, which is powered by a rechargeable battery, is designed to detect, amplify, filter and transmit the ECG signals. The coordinator receives the data and sends it to PC. Finally the signals are displayed on the GUI. In order to control the power consumption of sensor node, a dynamic power adjustment method is applied to automatically adjust the transmission power of the sensor node according to the received signal strength indicator (RSSI), which is related to the distance and obstacle between sensor node and coordinator. The system is evaluated when the user, who wears the sensor, is walking and running. A promising performance is achieved even under body motion. The power consumption can be significantly reduced with this dynamic power adjustment method.

  7. Long term dynamics of the high luminosity Large Hadron Collider with crab cavities

    Science.gov (United States)

    Barranco García, J.; De Maria, R.; Grudiev, A.; Tomás García, R.; Appleby, R. B.; Brett, D. R.

    2016-10-01

    The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 200 - 300 fb-1 per year, including the contribution from the upgrade of the injector chain. For the HL-LHC the larger crossing angle together with a smaller beta function at the collision point would result in more than 70% luminosity loss due to the incomplete geometric overlap of colliding bunches. To recover head-on collisions at the high-luminosity particle-physics detectors ATLAS and CMS and benefit from the very low β* provided by the Achromatic Telescopic Squeezing (ATS) optics, a local crab cavity scheme provides transverse kicks to the proton bunches. The tight space constraints at the location of these cavities leads to designs which are axially non-symmetric, giving rise to high order multipoles components of the main deflecting mode and, since these kicks are harmonic in time, we expand them in a series of multipoles in a similar fashion as is done for static field magnets. In this work we calculate, for the first time, the higher order multipoles and their impact on beam dynamics for three different crab cavity prototypes. Different approaches to calculate the multipoles are presented. Furthermore, we perform the first calculation of their impact on the long term stability of the machine using the concept of dynamic aperture.

  8. Communication: dynamical embedding: correct quantum response from coupling TDDFT for a small cluster with classical near-field electrodynamics for an extended region.

    Science.gov (United States)

    Gao, Yi; Neuhauser, Daniel

    2013-05-14

    We show how to obtain the correct electronic response of a large system by embedding; a small region is propagated by TDDFT (time-dependent density functional theory) simultaneously with a classical electrodynamics evolution using the Near-Field method over a larger external region. The propagations are coupled through a combined time-dependent density yielding a common Coulomb potential. We show that the embedding correctly describes the plasmonic response of a Mg(0001) slab and its influence on the dynamical charge transfer between an adsorbed H2O molecule and the substrate, giving the same spectral shape as full TDDFT (similar plasmon peak and molecular-dependent differential spectra) with much less computational effort. The results demonstrate that atomistic embedding electrodynamics is promising for nanoplasmonics and nanopolaritonics.

  9. The long-term reliability of static and dynamic Quantitative Sensory Testing in healthy individuals.

    Science.gov (United States)

    Marcuzzi, Anna; Wrigley, Paul J; Dean, Catherine M; Adams, Roger; Hush, Julia M

    2017-03-21

    Quantitative sensory tests (QST) have been increasingly used to investigate alterations in somatosensory function in a wide range of painful conditions. The interpretation of these findings is based on the assumption that the measures are stable and reproducible. To date, reliability of QST has been investigated for short test-retest intervals. The aim of this study was to investigate the long-term reliability of a multimodal QST assessment in healthy people, with testing conducted on three occasions over 4-months. Forty-two healthy people were enrolled in the study. Static and dynamic tests were performed, including cold and heat pain threshold (CPT, HPT), mechanical wind up (WUR), pressure pain threshold (PPT), two-point discrimination (TPD) and conditioned pain modulation (CPM). Systematic bias, relative reliability and agreement were analysed using repeated measure ANOVA, intraclass correlation coefficients (ICCs3,1) and standard error of the measurement (SEM), respectively. Static QST (CPT, HPT, PPT and TPD) showed good to excellent reliability (ICCs: 0.68 to 0.90). Dynamic QST (WUR and CPM) showed poor to good reliability (ICCs: 0.35 to 0.61). A significant linear decrease over time was observed for mechanical QST at the back (PPT and TPD) and for CPM (p<0.01). Static QST were stable over a period of 4 months; however, a small systematic decrease over time has been observed for mechanical QST. Dynamic QST showed considerable variability over time; in particular, CPM using PPT as the test stimulus did not show adequate reliability, suggesting that this test paradigm may be less useful for monitoring individuals over time.

  10. Long-term and seasonal dynamics of dengue in Iquitos, Peru.

    Directory of Open Access Journals (Sweden)

    Steven T Stoddard

    2014-07-01

    Full Text Available Long-term disease surveillance data provide a basis for studying drivers of pathogen transmission dynamics. Dengue is a mosquito-borne disease caused by four distinct, but related, viruses (DENV-1-4 that potentially affect over half the world's population. Dengue incidence varies seasonally and on longer time scales, presumably driven by the interaction of climate and host susceptibility. Precise understanding of dengue dynamics is constrained, however, by the relative paucity of laboratory-confirmed longitudinal data.We studied 10 years (2000-2010 of laboratory-confirmed, clinic-based surveillance data collected in Iquitos, Peru. We characterized inter and intra-annual patterns of dengue dynamics on a weekly time scale using wavelet analysis. We explored the relationships of case counts to climatic variables with cross-correlation maps on annual and trimester bases.Transmission was dominated by single serotypes, first DENV-3 (2001-2007 then DENV-4 (2008-2010. After 2003, incidence fluctuated inter-annually with outbreaks usually occurring between October and April. We detected a strong positive autocorrelation in case counts at a lag of ∼ 70 weeks, indicating a shift in the timing of peak incidence year-to-year. All climatic variables showed modest seasonality and correlated weakly with the number of reported dengue cases across a range of time lags. Cases were reduced after citywide insecticide fumigation if conducted early in the transmission season.Dengue case counts peaked seasonally despite limited intra-annual variation in climate conditions. Contrary to expectations for this mosquito-borne disease, no climatic variable considered exhibited a strong relationship with transmission. Vector control operations did, however, appear to have a significant impact on transmission some years. Our results indicate that a complicated interplay of factors underlie DENV transmission in contexts such as Iquitos.

  11. Long-term dynamics of dissolved organic carbon: implications for drinking water supply.

    Science.gov (United States)

    Ledesma, José L J; Köhler, Stephan J; Futter, Martyn N

    2012-08-15

    Surface waters are the main source of drinking water in many regions. Increasing organic carbon concentrations are a cause for concern in Nordic countries since both dissolved and particulate organic carbon can transport contaminants and adversely affect drinking water treatment processes. We present a long-term study of dynamics of total (particulate and dissolved) organic carbon (TOC) concentrations in the River Fyris. This river supplies drinking water to approximately 200000 people in Uppsala, Sweden. The River Fyris is a main tributary to Lake Mälaren, which supplies drinking water to approximately 2 million people in the greater Stockholm area. Utilities responsible for drinking water supply in both Uppsala and Stockholm have expressed concerns about possible increases in TOC. We evaluate organic carbon dynamics within the Fyris catchment by calculating areal mass exports using observed TOC concentrations and modeled flows and by modeling dissolved organic carbon (as a proxy for TOC) using the dynamic, process based INCA-C model. Exports of TOC from the catchment ranged from 0.8 to 5.8 g m(-2) year(-1) in the period 1995-2010. The variation in annual exports was related to climatic variability which influenced seasonality and amount of runoff. Exports and discharge uncoupled at the end of 2008. A dramatic increase in TOC concentrations was observed in 2009, which gradually declined in 2010-2011. INCA-C successfully reproduced the intra- and inter-annual variation in concentrations during 1996-2008 and 2010-2011 but failed to capture the anomalous increase in 2009. We evaluated a number of hypotheses to explain the anomaly in 2009 TOC values, ultimately none proved satisfactory. We draw two main conclusions: there is at least one unknown or unmeasured process controlling or influencing surface water TOC and INCA-C can be used as part of the decision-making process for current and future use of rivers for drinking water supply.

  12. A minimalistic approach to static and dynamic electron correlations: Amending generalized valence bond method with extended random phase approximation correlation correction

    Science.gov (United States)

    Chatterjee, Koushik; Pastorczak, Ewa; Jawulski, Konrad; Pernal, Katarzyna

    2016-06-01

    A perfect-pairing generalized valence bond (GVB) approximation is known to be one of the simplest approximations, which allows one to capture the essence of static correlation in molecular systems. In spite of its attractive feature of being relatively computationally efficient, this approximation misses a large portion of dynamic correlation and does not offer sufficient accuracy to be generally useful for studying electronic structure of molecules. We propose to correct the GVB model and alleviate some of its deficiencies by amending it with the correlation energy correction derived from the recently formulated extended random phase approximation (ERPA). On the examples of systems of diverse electronic structures, we show that the resulting ERPA-GVB method greatly improves upon the GVB model. ERPA-GVB recovers most of the electron correlation and it yields energy barrier heights of excellent accuracy. Thanks to a balanced treatment of static and dynamic correlation, ERPA-GVB stays reliable when one moves from systems dominated by dynamic electron correlation to those for which the static correlation comes into play.

  13. Short-term dynamics of thalamocortical and intracortical synapses onto layer 6 neurons in neocortex.

    Science.gov (United States)

    Beierlein, Michael; Connors, Barry W

    2002-10-01

    Layer 6 is the main source of neocortical connections back to specific thalamic nuclei. Corticothalamic (CT) systems play an important role in shaping sensory input, but little is known about the functional circuitry that generates CT activity. We recorded from the two main types of neurons in layer 6, regular-spiking (RS; pyramidal neurons) and fast-spiking (FS; inhibitory interneurons) cells and compared the physiological properties of different excitatory inputs. Thalamic stimulation evoked two monosynaptic inputs with distinct properties: suspected thalamocortical (TC) synaptic events had short latencies, short-term synaptic depression, and paired-pulse responses that suggested subnormal axonal conduction. A second group of synaptic responses likely originated from intracortical collaterals of CT cells that were antidromically activated from the thalamus. These intracortical responses had longer latencies, short-term synaptic facilitation, and were transmitted by axons with supernormal conduction. Suspected TC inputs to FS cells had significantly larger amplitudes than those onto RS cells. Dual recordings from neighboring neurons in layer 6 revealed both facilitating and depressing synaptic connections; the depressing synapses were probably formed by layer 6 cells that do not project to the thalamus, and thus were not sampled by thalamic stimulation. We conclude that layer 6 neurons integrate a variety of inputs with distinct temporal dynamics that are determined by the presynaptic cell type.

  14. Long-term dynamics of buried organic carbon in colluvial soils

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2013-08-01

    Full Text Available Colluvial soils are enriched in soil organic carbon (SOC in comparison to the soils of upslope areas due to the deposition and subsurface burial of SOC. It has been suggested that the burial of SOC has important implications for the global carbon cycle, but the long-term dynamics of buried SOC remains poorly constrained. We address this issue by determining the SOC burial efficiency (i.e., the fraction of originally deposited SOC that is preserved in colluvial deposits of buried SOC as well as the SOC stability in colluvial soils. We quantify the turnover rate of deposited SOC by establishing sediment and SOC burial chronologies. The SOC stability is derived from soil incubation experiments and the δ13C values of SOC. The C burial efficiency was found to decrease exponentially with time reaching a constant ratio of approximately 17%. This exponential decrease is attributed to the increasing recalcitrance of buried SOC with time and a less favourable environment for SOC decomposition with increasing depth. Buried SOC is found to be more stable and degraded in comparison to SOC sampled at the same depth at a stable site. This is due to preferential mineralization of the labile fraction of deposited SOC resulting in enrichment of more degraded and recalcitrant SOC in colluvial soils. In order to better understand the long-term effects of soil erosion for the global C cycle, the temporal variation of deposited SOC and its controlling factors need to be characterized and quantified.

  15. SU-E-QI-03: Compartment Modeling of Dynamic Brain PET - The Effect of Scatter and Random Corrections On Parameter Errors

    Energy Technology Data Exchange (ETDEWEB)

    Häggström, I; Karlsson, M; Larsson, A [Umeå University, Umeå (Sweden); Schmidtlein, C [Memorial Sloan Kettering Cancer Center, NY, NY (United States)

    2014-06-15

    Purpose: To investigate the effects of corrections for random and scattered coincidences on kinetic parameters in brain tumors, by using ten Monte Carlo (MC) simulated dynamic FLT-PET brain scans. Methods: The GATE MC software was used to simulate ten repetitions of a 1 hour dynamic FLT-PET scan of a voxelized head phantom. The phantom comprised six normal head tissues, plus inserted regions for blood and tumor tissue. Different time-activity-curves (TACs) for all eight tissue types were used in the simulation and were generated in Matlab using a 2-tissue model with preset parameter values (K1,k2,k3,k4,Va,Ki). The PET data was reconstructed into 28 frames by both ordered-subset expectation maximization (OSEM) and 3D filtered back-projection (3DFBP). Five image sets were reconstructed, all with normalization and different additional corrections C (A=attenuation, R=random, S=scatter): Trues (AC), trues+randoms (ARC), trues+scatters (ASC), total counts (ARSC) and total counts (AC). Corrections for randoms and scatters were based on real random and scatter sinograms that were back-projected, blurred and then forward projected and scaled to match the real counts. Weighted non-linearleast- squares fitting of TACs from the blood and tumor regions was used to obtain parameter estimates. Results: The bias was not significantly different for trues (AC), trues+randoms (ARC), trues+scatters (ASC) and total counts (ARSC) for either 3DFBP or OSEM (p<0.05). Total counts with only AC stood out however, with an up to 160% larger bias. In general, there was no difference in bias found between 3DFBP and OSEM, except in parameter Va and Ki. Conclusion: According to our results, the methodology of correcting the PET data for randoms and scatters performed well for the dynamic images where frames have much lower counts compared to static images. Generally, no bias was introduced by the corrections and their importance was emphasized since omitting them increased bias extensively.

  16. Energy balance during intense and super-intense magnetic storms using an Akasofu ɛ parameter corrected by the solar wind dynamic pressure

    Science.gov (United States)

    de Lucas, A.; Gonzalez, W. D.; Echer, E.; Guarnieri, F. L.; Dal Lago, A.; da Silva, M. R.; Vieira, L. E. A.; Schuch, N. J.

    2007-11-01

    Geomagnetic storms are large disturbances in the Earth's magnetosphere caused by enhanced solar wind magnetosphere energy transfer. One of the main manifestations of a geomagnetic storm is the ring current enhancement. It is responsible for the decrease in the geomagnetic field observed at ground stations. In this work, we study the ring current dynamics during two different levels of magnetic storms. Thirty-three events are selected during the period 1981 2004. Eighteen out of 33 events are very intense (or super-intense) magnetic storms (Dst ⩽-250 nT) and the remaining are intense magnetic storms (-250ISEE-3) and geomagnetic indices (Dst and Sym-H) are analyzed. Our aim is to evaluate the interplanetary characteristics (interplanetary dawn dusk electric field, interplanetary magnetic field component BS), the ɛ parameter, and the total energy input into the magnetosphere (Wɛ) for these two classes of magnetic storms. Two corrections on the ɛ energy coupling function are made: the first one is an already known correction in the magnetopause radius to take into account the variation in the solar wind pressure. The second correction on the Akasofu parameter, first proposed in this work, accounts for the reconnection efficiency as a function of the solar wind ram pressure. Geomagnetic data/indices are also employed to study the ring current dynamics and to search for the differences in the storm evolution during these events. Our corrected ɛ parameter is shown to be more adequate to explain storm energy balance because the energy input and the energy dissipated in the ring current are in better agreement with modern estimates as compared with previous works. For super-intense storms, the correction of the Akasofu ɛ is on average a scaling factor of 3.7, whilst for intense events, this scaling factor is on average 3.4. The injected energy during the main phase using corrected ɛ can be considered a criterion to separate intense from very intense storms. Other

  17. Dynamic response of land use and river nutrient concentration to long-term climatic changes.

    Science.gov (United States)

    Bussi, Gianbattista; Janes, Victoria; Whitehead, Paul G; Dadson, Simon J; Holman, Ian P

    2017-03-10

    The combined indirect and direct impacts of land use change and climate change on river water quality were assessed. A land use allocation model was used to evaluate the response of the catchment land use to long-term climatic changes. Its results were used to drive a water quality model and assess the impact of climatic alterations on freshwater nitrate and phosphorus concentrations. Climatic projections were employed to estimate the likelihood of such response. The River Thames catchment (UK) was used as a case-study. If land use is considered as static parameter, according to the model results, climate change alone should reduce the average nitrate concentration, although just by a small amount, by the 2050s in the Lower Thames, due to reduced runoff (and lower export of nitrate from agricultural soils) and increased instream denitrification, and should increase the average phosphorus concentration by 12% by the 2050s in the Lower Thames, due to a reduction of the effluent dilution capacity of the river flow. However, the results of this study also show that these long-term climatic alterations are likely to lead to a reduction in the arable land in the Thames, replaced by improved grassland, due to a decrease in agriculture profitability in the UK. Taking into account the dynamic co-evolution of land use with climate, the average nitrate concentration is expected to be decreased by around 6% by the 2050s in both the upper and the lower Thames, following the model results, and the average phosphorus concentration increased by 13% in the upper Thames and 5% in the lower Thames. On the long term (2080s), nitrate is expected to decrease by 9% and 8% (upper and lower Thames respectively) and phosphorus not to change in the upper thames and increase by 5% in the lower Thames.

  18. Sci-Fri AM: Imaging - 09: Serial estimation of cross-talk for correction in dual-isotope imaging with dynamic tracers.

    Science.gov (United States)

    Wells, R G; Lockwood, J; Wei, L; Duan, D; Fernando, P; Bensimon, C; Ruddy, T D

    2012-07-01

    The recent radioisotope shortage has led to interest in non-Tc99m-based tracers. We have developed a novel I-123-labelled myocardial perfusion imaging tracer. We compare the I123-tracer to the clinical standard of Tc99m tetrofosmin in vivo in a rat model using a small-animal SPECT/CT camera. SPECT distinguishes different isotopes based on the different energies of the emitted gamma rays and thus allows simultaneous comparison of two tracer distributions in the same animal. Dual-isotope imaging is complicated by cross-talk between the energy windows of the isotopes. Standard energy-window-based correction methods are difficult to employ because of the proximity in energy of Tc99m (140keV) and I123 (159keV). Imaging the second tracer's energy window prior to its injection provides an estimate of the cross-talk. However, this estimate is only accurate if the tracer distribution is static. We use serial imaging prior to the introduction of the second tracer to estimate the dynamics of the first tracer and interpolate the cross-talk images to provide a more accurate correction. We used rat models of myocardial disease (n=3). I123 tracer was injected and imaged for one hour at 20min intervals. The Tc99m tetrofosmin was then injected and 30min later, a dual-isotope image was obtained. The impact of this approach is assessed by comparing the differences in the Tc99m-tetrofosmin image using this method with correction by simple correction for physical decay. The interpolative approach improves the accuracy of the correction by 2%-5% and thereby enhances the comparison of the two tracers. © 2012 American Association of Physicists in Medicine.

  19. The steps that can take us miles: Examining the short-term dynamics of long-term daily goal pursuit.

    Science.gov (United States)

    Wilkowski, Benjamin M; Ferguson, Elizabeth Louise

    2016-04-01

    Cybernetic models suggest that to achieve one's long-term goals, one must create specific plans, enact these plan, monitor progress toward the goal, and resist temptations. Although many studies have examined these proposals in laboratory settings, few studies have examined such processes in daily life. This was the explicit purpose of the current investigation. Participants identified 4 long-term goals during an orientation session. They then completed a diary protocol in which they reported on these self-regulatory processes. The results were largely consistent with predictions. Of the 20 hypotheses examined, 17 were significant in the expected direction. For example, testing led to the initiation of long-term goal operations, which in turn led to goal progress. Likewise, temptations led to self-control operations, which in turn led to the successful resistance of temptations. The investigation thus suggests that cybernetic principles have broad relevance to understanding goal pursuit in daily life.

  20. Effect of accelerated corneal crosslinking combined with transepithelial photorefractive keratectomy on dynamic corneal response parameters and biomechanically corrected intraocular pressure measured with a dynamic Scheimpflug analyzer in healthy myopic patients.

    Science.gov (United States)

    Lee, Hun; Roberts, Cynthia J; Ambrósio, Renato; Elsheikh, Ahmed; Kang, David Sung Yong; Kim, Tae-Im

    2017-07-01

    To evaluate the effect of accelerated corneal crosslinking (CXL) combined with transepithelial photorefractive keratectomy (PRK) on changes in new dynamic corneal response parameters and the biomechanically corrected intraocular pressure (IOP) measured using a dynamic Scheimpflug analyzer (Corvis ST). Yonsei University College of Medicine and Eyereum Eye Clinic, Seoul, South Korea. Retrospective case series. Medical records of eyes of healthy myopic patients having transepithelial PRK or transepithelial PRK with CXL were examined. Main outcome variables were the biomechanically corrected IOP and new dynamic corneal response parameters including the deformation amplitude ratio at 1.0 mm (DAR1) and at 2.0 mm (DAR2), stiffness at first applanation and at highest concavity, and the integrated inverse radius preoperatively and 6 months postoperatively. The study comprised 69 eyes (69 patients); 35 had transepithelial PRK and 34, transepithelial PRK with CXL. The DAR1, DAR2, and integrated inverse radius significantly increased, while stiffness at first applanation and at highest concavity decreased postoperatively in both groups. Changes in the DAR2 and integrated inverse radius in the transepithelial PRK group were significantly larger than in the transepithelial PRK with CXL group without and with analysis of covariance with the spherical equivalent change or corneal thickness change as a covariate. No significant differences in the biomechanically corrected IOP occurred preoperatively or postoperatively in either group. Results indicate that prophylactic CXL combined with transepithelial PRK has a role in reducing the change in corneal biomechanical properties. The dynamic Scheimpflug analyzer showed stable biomechanically corrected IOP measurements preoperatively and postoperatively. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. Long-term Carbon and Nitrogen Dynamics at SPRUCE Revealed through Stable Isotopes in Peat Profiles

    Science.gov (United States)

    Hobbie, E. A.

    2015-12-01

    Carbon and nitrogen turnover in peatlands is of considerable interest because peat is a large reservoir of stored carbon that could emit greenhouse gases in response to climate change. Because peat cores preserve a long-term record of system carbon and nitrogen dynamics, it is possible to use stable isotopes as markers of changes in carbon (C) and nitrogen (N) dynamics over time. Here, we used δ15N and δ13C patterns throughout the depth profile of peat cores to understand controls over C-N cycling in the Marcell S1 forested bog in northern Minnesota. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, %C, %N, and each other. Negative correlation of δ15N with %N presumably reflected removal of 15N-depleted N via denitrification, diffusion, or plant N transfer via mycorrhizal fungi. A step increase in the depth coefficient for δ15N of ~3‰ from -25 cm to -35 cm suggested that the N removal process primarily operates at a discrete depth corresponding to the juncture between aerobic and anaerobic layers defined by the water table. Higher δ15N and lower δ13C in plots closer to uplands may reflect distinct hydrology and accompanying shifts in C and N dynamics in the lagg area fringing the bog. The Suess effect (declining δ13CO2 since the Industrial Revoluation) and aerobic decomposition lowered δ13C in recent surficial samples. Small increases in δ13C at -112 cm (4300 calibrated years BP) and -85 cm (3800 calibrated years BP) may reflect C dynamics during a suspected transitional fen stage (based on paleoecology at a nearby bog), when reduced methanotrophy retained less 13C-depleted carbon derived from methane than in later periods. The C/N decreased until about -85 cm and thereafter remained steady, suggesting that the active zone of aerobic processing during drought may extend to this depth. The inflection point in calculated carbon accumulation rates at this depth supports this conclusion.

  2. Identification of long-term trends in vegetation dynamics in the Guinea savannah region of Nigeria

    Science.gov (United States)

    Osunmadewa, Babatunde A.; Wessollek, Christine; Karrasch, Pierre

    2014-10-01

    The availability of newly generated data from Advanced Very High Resolution Radiometer (AVHRR) covering the last three decades has broaden our understanding of vegetation dynamics (greening) from global to regional scale through quantitative analysis of seasonal trends in vegetation time series and climatic variability especially in the Guinea savannah region of Nigeria where greening trend is inconsistent. Due to the impact of changes in global climate and sustainability of means of human livelihood, increasing interest on vegetation productivity has become important. The aim of this study is to examine association between NDVI and rainfall using remotely sensed data, since vegetation dynamics (greening) has a high degree of association with weather parameters. This study therefore analyses trends in regional vegetation dynamics in Kogi state, Nigeria using bi-monthly AVHRR GIMMS 3g (Global Inventory Modelling and Mapping Studies) data and TAMSAT (Tropical Applications of Meteorology Satellite) monthly data both from 1983 to 2011 to identify changes in vegetation greenness over time. Analysis of changes in the seasonal variation of vegetation greenness and climatic drivers was conducted for selected locations to further understand the causes of observed interannual changes in vegetation dynamics. For this study, Mann-Kendall (MK) monotonic method was used to analyse long-term inter-annual trends of NDVI and climatic variable. The Theil-Sen median slope was used to calculate the rate of change in slopes between all pair wise combination and then assessing the median over time. Trends were also analysed using a linear model method, after seasonality had been removed from the original NDVI and rainfall data. The result of the linear model are statistically significant (p <0.01) in all the study location which can be interpreted as increase in vegetation trend over time (greening). Also the result of the NDVI trend analysis using Mann-Kendall test shows an increasing

  3. Long-term variations of the Black Sea dynamics and their impact on the marine ecosystem

    Science.gov (United States)

    Kubryakov, Arseny A.; Stanichny, Sergey V.; Zatsepin, Andrey G.; Kremenetskiy, Viacheslav V.

    2016-11-01

    Satellite altimetry data are used to study the long-term dynamics variability of the Black Sea from 1993 to 2013, its dependence on wind forcing and its impact on the marine ecosystem. Basin-scale dynamics have significant interseasonal and interannual variability. The most distinctly observed feature of the interannual dynamics variability is an almost twofold increase of the current kinetic energy from 2002 to 2012, based on anomaly weak values from 1998 to 2001. The amplitudes of a seasonal cycle of current velocity variability from 2002 to 2102 were two times higher than the amplitudes from 1998 to 2001. The seasonal variability of the current Mean Kinetic Energy (MKE) significantly varies among the years. Although usually maximal values of MKE are observed in winter and minimal values are observed in summer, the seasonal variability may exhibit two distinct peaks in spring and autumn, or even can be opposite with maximum values observed in warm period of a year. The variability of wind stress curl (or the Ekman pumping velocity) averaged over the basin is the main factor for the observed changes in the Black Sea dynamics. The analysis shows that the integral effect of the cyclonic wind curl causes water divergence in the centre of the basin, rising sea level gradients and Rim current intensification. The mean kinetic energy of the Black Sea currents follows the variability of Ekman pumping on seasonal and interannual time scales with a time delay of approximately two weeks. This lag is consistent with the estimated time that is required for water particles to drift from the central part to the basin periphery due to rising Ekman divergence. We employ an eddy-identification method to show that the interannual variability of the number of mesoscale eddies in the basin and their energy are opposite to the variability of the mean kinetic energy of the Black Sea currents and Ekman pumping over the basin. The number of eddies and their total energy decreased after

  4. Error Correction in Classroom

    Institute of Scientific and Technical Information of China (English)

    Dr. Grace Zhang

    2000-01-01

    Error correction is an important issue in foreign language acquisition. This paper investigates how students feel about the way in which error correction should take place in a Chinese-as-a foreign-language classroom, based on empirical data of a large scale. The study shows that there is a general consensus that error correction is necessary. In terms of correction strategy, the students preferred a combination of direct and indirect corrections, or a direct only correction. The former choice indicates that students would be happy to take either so long as the correction gets done.Most students didn't mind peer correcting provided it is conducted in a constructive way. More than halfofthe students would feel uncomfortable ifthe same error they make in class is corrected consecutively more than three times. Taking these findings into consideration, we may want to cncourage peer correcting, use a combination of correction strategies (direct only if suitable) and do it in a non-threatening and sensitive way. It is hoped that this study would contribute to the effectiveness of error correction in a Chinese language classroom and it may also have a wider implication on other languages.

  5. Pole Inflation - Shift Symmetry and Universal Corrections

    CERN Document Server

    Broy, Benedict J; Roest, Diederik; Westphal, Alexander

    2015-01-01

    An appealing explanation for the Planck data is provided by inflationary models with a non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large field values by including higher-order poles. We show that the resulting corrections to the inflationary dynamics and predictions are universal at lowest order, and can induce power loss at large angular scales. At lowest order there are no corrections from a pole of one order higher; this is referred to as extended no-scale in string theory and we explain why this is a general phenomenon. Finally, we outline which other corrections may arise as string loop corrections.

  6. A Kalman Filter Based Correction Model for Short-Term Wind Power Prediction%卡尔曼滤波修正的风电场短期功率预测模型

    Institute of Scientific and Technical Information of China (English)

    赵攀; 戴义平; 夏俊荣; 盛迎新

    2011-01-01

    A Kalman filter based correction model for short-term wind power prediction was proposed to solve the problem of wind energy prediction accuracy constraint induced by the systematic errors in meteorological parameters from the numerical weather prediction (NWP) model. The wind speed data from NWP were corrected dynamically by using the Kalman filter algorithm and the improved NWP set used for wind power prediction was formed by combining the corrected wind speed data with other meteorological data. The original neural network prediction model and the corrected neural network prediction model were trained by using the raw NWP set and the improved NWP set, respectively. The analysis on the comparison between the simulation data and the measured data in a same time interval shows that, the corrected wind speed series by the Kalman filter are very close to observed wind speed; the mean error and the mean absolute error are smaller; the root mean square error decreases from 17. 73% to 11.32%. It seems that the wind power prediction model proposed has a clearly higher accuracy.%针对数值天气预报模型输出的气象参数存在系统误差而导致风电场功率预测精度受到制约的问题,提出了一种基于卡尔曼滤波修正的风电场短期功率预测模型.使用卡尔曼滤波算法对数值天气预报输出的风速数据进行动态修正,并结合其他气象数据形成新的用于风电功率预测的修正气象数据集合;根据原始气象数据和修正气象数据这2个训练集分别建立了风电场功率输出的原始神经网络、修正神经网络的预测模型.经同一时间区间内的实测数据与模型分析数据的对比分析表明:通过卡尔曼滤波修正的风速数据能够很好地跟踪实际风速数据的变化趋势,平均误差与绝对平均误差比较小;所提模型能够显著降低预测结果的均方根误差,使其从未修正前的17.73%降低至11.32%,证明预测精度得到了明显提高.

  7. Long-term Dynamical Behavior of Highly Perturbed Natural and Artificial Celestial Bodies

    Science.gov (United States)

    Rosengren, Aaron J.

    This thesis explores the dynamical evolution of celestial bodies, both natural and artificial, which are strongly perturbed by solar radiation pressure---a non-gravitational force that has played an increasingly important role in celestial mechanics since the early 1900s. The particular focus is on the high area-to-mass ratio (HAMR) space debris discovered in near geosynchronous Earth orbit (GEO) through optical observations in 2004, and on micron-sized circumplanetary dust particles in the outer Saturnian system. The formalism developed can also be applied to---and, indeed, was unquestionably influenced by---the orbital motion of spacecraft about small bodies (asteroids and comets). The chief difficulties which arise in getting an accurate understanding of the motion of such bodies in highly perturbed dynamical environments come, in part, from the nonlinearity of the dynamical system, but more so from the inadequacy of the classical approaches and methods. While modern formulations based on numerical integrations can give "precise" solutions for specific initial conditions, these afford little insight into the nature of the problem or the essential dependence of the perturbed motion on the system parameters. The predominant perturbations acting on HAMR objects and circumplanetary dust grains are solar radiation pressure, planetary oblateness, and third-body gravitational interactions induced by the Sun and nearby natural satellites. We developed first-order averaged models, based on the Milankovitch formulation of perturbation theory, which govern the long-term evolution of orbits subject to these perturbing forces. The unexpectedly rich results obtained by the use of this vector formalism are due to certain important circumstances in celestial and quantum mechanics which gave rise to its origin and development. An attempt has been made to trace these historical developments and to put them into the perspective of the present. The averaged equations of motion hold

  8. Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations

    Science.gov (United States)

    Kalicinsky, Christoph; Knieling, Peter; Koppmann, Ralf; Offermann, Dirk; Steinbrecht, Wolfgang; Wintel, Johannes

    2016-12-01

    We present the analysis of annual average OH* temperatures in the mesopause region derived from measurements of the Ground-based Infrared P-branch Spectrometer (GRIPS) at Wuppertal (51° N, 7° E) in the time interval 1988 to 2015. The new study uses a temperature time series which is 7 years longer than that used for the latest analysis regarding the long-term dynamics. This additional observation time leads to a change in characterisation of the observed long-term dynamics. We perform a multiple linear regression using the solar radio flux F10.7 cm (11-year cycle of solar activity) and time to describe the temperature evolution. The analysis leads to a linear trend of (-0.089 ± 0.055) K year-1 and a sensitivity to the solar activity of (4.2 ± 0.9) K (100 SFU)-1 (r2 of fit 0.6). However, one linear trend in combination with the 11-year solar cycle is not sufficient to explain all observed long-term dynamics. In fact, we find a clear trend break in the temperature time series in the middle of 2008. Before this break point there is an explicit negative linear trend of (-0.24 ± 0.07) K year-1, and after 2008 the linear trend turns positive with a value of (0.64 ± 0.33) K year-1. This apparent trend break can also be described using a long periodic oscillation. One possibility is to use the 22-year solar cycle that describes the reversal of the solar magnetic field (Hale cycle). A multiple linear regression using the solar radio flux and the solar polar magnetic field as parameters leads to the regression coefficients Csolar = (5.0 ± 0.7) K (100 SFU)-1 and Chale = (1.8 ± 0.5) K (100 µT)-1 (r2 = 0.71). The second way of describing the OH* temperature time series is to use the solar radio flux and an oscillation. A least-square fit leads to a sensitivity to the solar activity of (4.1 ± 0.8) K (100 SFU)-1, a period P = (24.8 ± 3.3) years, and an amplitude Csin = (1.95 ± 0.44) K of the oscillation (r2 = 0.78). The most important finding here is that using this

  9. How Dynamic Consumer Response, Competitor Response, Company Support, and Company Inertia Shape Long-Term Marketing Effectiveness

    OpenAIRE

    Koen Pauwels

    2004-01-01

    Long-term marketing effectiveness is a high-priority research topic for managers, and emerges from the complex interplay among dynamic reactions of several market players. This paper introduces restricted policy simulations to distinguish four dynamic forces: consumer response, competitor response, company inertia, and company support. A rich marketing dataset allows the analysis of price, display, feature, advertising, and product-line extensions. The first finding is that consumer response ...

  10. Long-term population dynamics of a managed burrowing owl colony

    Science.gov (United States)

    Barclay, John H.; Korfanta, Nicole M.; Kauffman, Matthew J.

    2011-01-01

    We analyzed the population dynamics of a burrowing owl (Athene cunicularia) colony at Mineta San Jose International Airport in San Jose, California, USA from 1990-2007. This colony was managed by using artificial burrows to reduce the occurrence of nesting owls along runways and within major airport improvement projects during the study period. We estimated annual reproduction in natural and artificial burrows and age-specific survival rates with mark-recapture techniques, and we estimated the relative contribution of these vital rates to population dynamics using a life table response experiment. The breeding colony showed 2 distinct periods of change: high population growth from 7 nesting pairs in 1991 to 40 pairs in 2002 and population decline to 17 pairs in 2007. Reproduction was highly variable: annual nesting success (pairs that raised =1 young) averaged 79% and ranged from 36% to 100%, whereas fecundity averaged 3.36 juveniles/pair and ranged from 1.43 juveniles/pair to 4.54 juveniles/pair. We estimated annual adult survival at 0.710 during the period of colony increase from 1996 to 2001 and 0.465 during decline from 2002 to 2007, but there was no change in annual survival of juveniles between the 2 time periods. Long-term population growth rate (lambda) estimated from average vital rates was lambdaa=1.072 with lambdai=1.288 during colony increase and lambdad=0.921 (DELTA lambda=0.368) during decline. A life table response experiment showed that change in adult survival rate during increasing and declining phases explained more than twice the variation in growth rate than other vital rates. Our findings suggest that management and conservation of declining burrowing owl populations should address factors that influence adult survival.

  11. Predicting Agricultural Management Influence on Long-Term Soil Organic Carbon Dynamics: Implications for Biofuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Gollany, H. T. [USDA ARS; Rickman, R. W. [USDA ARS; Albrecht, S. L. [USDA ARS; Liang, Y. [University of Arkansas; Kang, Shujiang [ORNL; Machado, S. [Oregon State University, Corvallis

    2011-01-01

    Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1 19 C), precipitation (402 973 mm), and SOC (5.89 33.58 g SOC kg 1) at the LTE sites were significantly related (r 2 = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks

  12. Rebuilding after collapse: evidence for long-term cohort dynamics in the native Hawaiian rain forest

    Science.gov (United States)

    Boehmer, Hans Juergen; Wagner, Helene H.; Jacobi, James D.; Gerrish, Grant C.; Mueller-Dombois, Dieter

    2013-01-01

    Questions: Do long-term observations in permanent plots confirm the conceptual model of Metrosideros polymorpha cohort dynamics as postulated in 1987? Do regeneration patterns occur independently of substrate age, i.e. of direct volcanic disturbance impact? Location: The windward mountain slopes of the younger Mauna Loa and the older Mauna Kea volcanoes (island of Hawaii, USA). Methods: After widespread forest decline (dieback), permanent plots were established in 1976 in 13 dieback and 13 non-dieback patches to monitor the population structure of M. polymorpha at ca. 5-yr intervals. Within each plot of 20 × 20 m, all trees with DBH >2.5 cm were individually tagged, measured and tree vigour assessed; regeneration was quantified in 16 systematically placed subplots of 3 × 5 m. Data collected in the subplots included the total number of M. polymorpha seedlings and saplings (five stem height classes). Here we analyse monitoring data from six time steps from 1976 to 2003 using repeated measures ANOVA to test specific predictions derived from the 1987 conceptual model. Results: Regeneration was significantly different between dieback and non-dieback plots. In dieback plots, the collapse in the 1970s was followed by a ‘sapling wave’ that by 2003 led to new cohort stands of M. polymorpha. In non-dieback stands, seedling emergence did not result in sapling waves over the same period. Instead, a ‘sapling gap’ (i.e. very few or no M. polymorpha saplings) prevailed as typical for mature stands. Canopy dieback in 1976, degree of recovery by 2003 and the number of living trees in 2003 were unrelated to substrate age. Conclusions: Population development of M. polymorpha supports the cohort dynamics model, which predicts rebuilding of the forest with the same canopy species after dieback. The lack of association with substrate age suggests that the long-term maintenance of cohort structure in M. polymorpha does not depend on volcanic disturbance but may be related to

  13. Long-Term Bacterial Dynamics in a Full-Scale Drinking Water Distribution System

    KAUST Repository

    Prest, E. I.

    2016-10-28

    Large seasonal variations in microbial drinking water quality can occur in distribution networks, but are often not taken into account when evaluating results from short-term water sampling campaigns. Temporal dynamics in bacterial community characteristics were investigated during a two-year drinking water monitoring campaign in a full-scale distribution system operating without detectable disinfectant residual. A total of 368 water samples were collected on a biweekly basis at the water treatment plant (WTP) effluent and at one fixed location in the drinking water distribution network (NET). The samples were analysed for heterotrophic plate counts (HPC), Aeromonas plate counts, adenosine-tri-phosphate (ATP) concentrations, and flow cytometric (FCM) total and intact cell counts (TCC, ICC), water temperature, pH, conductivity, total organic carbon (TOC) and assimilable organic carbon (AOC). Multivariate analysis of the large dataset was performed to explore correlative trends between microbial and environmental parameters. The WTP effluent displayed considerable seasonal variations in TCC (from 90 × 103 cells mL-1 in winter time up to 455 × 103 cells mL-1 in summer time) and in bacterial ATP concentrations (<1–3.6 ng L-1), which were congruent with water temperature variations. These fluctuations were not detected with HPC and Aeromonas counts. The water in the network was predominantly influenced by the characteristics of the WTP effluent. The increase in ICC between the WTP effluent and the network sampling location was small (34 × 103 cells mL-1 on average) compared to seasonal fluctuations in ICC in the WTP effluent. Interestingly, the extent of bacterial growth in the NET was inversely correlated to AOC concentrations in the WTP effluent (Pearson’s correlation factor r = -0.35), and positively correlated with water temperature (r = 0.49). Collecting a large dataset at high frequency over a two year period enabled the characterization of previously

  14. Long-Term Bacterial Dynamics in a Full-Scale Drinking Water Distribution System.

    Science.gov (United States)

    Prest, E I; Weissbrodt, D G; Hammes, F; van Loosdrecht, M C M; Vrouwenvelder, J S

    2016-01-01

    Large seasonal variations in microbial drinking water quality can occur in distribution networks, but are often not taken into account when evaluating results from short-term water sampling campaigns. Temporal dynamics in bacterial community characteristics were investigated during a two-year drinking water monitoring campaign in a full-scale distribution system operating without detectable disinfectant residual. A total of 368 water samples were collected on a biweekly basis at the water treatment plant (WTP) effluent and at one fixed location in the drinking water distribution network (NET). The samples were analysed for heterotrophic plate counts (HPC), Aeromonas plate counts, adenosine-tri-phosphate (ATP) concentrations, and flow cytometric (FCM) total and intact cell counts (TCC, ICC), water temperature, pH, conductivity, total organic carbon (TOC) and assimilable organic carbon (AOC). Multivariate analysis of the large dataset was performed to explore correlative trends between microbial and environmental parameters. The WTP effluent displayed considerable seasonal variations in TCC (from 90 × 103 cells mL-1 in winter time up to 455 × 103 cells mL-1 in summer time) and in bacterial ATP concentrations (water temperature variations. These fluctuations were not detected with HPC and Aeromonas counts. The water in the network was predominantly influenced by the characteristics of the WTP effluent. The increase in ICC between the WTP effluent and the network sampling location was small (34 × 103 cells mL-1 on average) compared to seasonal fluctuations in ICC in the WTP effluent. Interestingly, the extent of bacterial growth in the NET was inversely correlated to AOC concentrations in the WTP effluent (Pearson's correlation factor r = -0.35), and positively correlated with water temperature (r = 0.49). Collecting a large dataset at high frequency over a two year period enabled the characterization of previously undocumented seasonal dynamics in the distribution

  15. Soil organic carbon dynamics under long-term fertilizations in arable land of northern China

    Science.gov (United States)

    Zhang, W. J.; Wang, X. J.; Xu, M. G.; Huang, S. M.; Liu, H.; Peng, C.

    2010-02-01

    Soil carbon sequestration is a complex process influenced by agricultural practices, climate and soil conditions. This paper reports a study of long-term fertilization impacts on soil organic carbon (SOC) dynamic from six long-term experiments. The experiment sites are located from warm-temperate zone with a double-cropping system of corn (Zea mays L.) - wheat (Triticum Aestivium L.) rotation, to mild-temperate zones with mono-cropping systems of continuous corn, or a three-year rotation of corn-wheat-wheat. Mineral fertilizer applications result in an increasing trend in SOC except in the arid and semi-arid areas with the mono-cropping systems. Additional manure application is important to maintain SOC level in the arid and semi-arid areas. Carbon conversion rate is significant lower in the warm-temperate zone with double cropping system (6.8%-7.7%) than that in the mild-temperate areas with mono-cropping systems (15.8%-31.0%). The conversion rate is significantly correlated with annual precipitation and active accumulative temperature, i.e., higher conversion rate under lower precipitation and/or temperature conditions. Moreover, soil high in clay content has higher conversion rate than soils low in clay content. Soil carbon sequestration rate ranges from 0.07 to 1.461 t ha-1 year-1 in the upland of northern China. There is significantly linear correlation between soil carbon sequestration and carbon input at most sites, indicating that these soils are not carbon-saturated thus have potential to migrate more CO2 from atmosphere.

  16. Simulating the Effects of Short-Term Synaptic Plasticity on Postsynaptic Dynamics in the Globus Pallidus

    Directory of Open Access Journals (Sweden)

    Moran eBrody

    2013-08-01

    Full Text Available The rat globus pallidus (GP is one of the nuclei of the basal ganglia and plays an important role in a variety of motor and cognitive processes. In vivo studies have shown that repetitive stimulation evokes complex modulations of GP activity. In vitro and computational studies have suggested that short-term synaptic plasticity (STP could be one of the underlying mechanisms. The current study used simplified single compartment modeling to explore the possible effect of STP on the activity of GP neurons during low and high frequency stimulation. To do this we constructed a model of a GP neuron connected to a small network of neurons from the three major input sources to GP neurons: striatum (Str, subthalamic nucleus (STN and GP collaterals. All synapses were implemented with a kinetic model of STP. The in vitro recordings of responses to low frequency repetitive stimulation were highly reconstructed, including rate changes and locking to the stimulus. Mainly involved were fast forms of plasticity which have been found at these synapses. . The simulations were qualitatively compared to a data set previously recorded in vitro in our lab. Reconstructions of experimental responses to high frequency stimulation required adding slower forms of plasticity to the STN and GP collateral synapses, as well as adding metabotropic receptors to the STN-GP synapses. These finding suggest the existence of as yet unreported slower short-term dynamics in the GP. The computational model made additional predictions about GP activity during low and high frequency stimulation that may further our understanding of the mechanisms underlying repetative stimulation of the GP.

  17. Long-Term Forest Dynamics and Land-Use Abandonment in the Mediterranean Mountains, Corsica, France

    Directory of Open Access Journals (Sweden)

    Almudena San Roman Sanz

    2013-06-01

    Full Text Available Human practices have had an impact on Mediterranean ecosystems for millennia, particularly through agricultural and pastoral activities. Since the mid-19th century, land-use abandonment has led to the expansion of shrubland and forest, especially in the mountainous areas of the northern Mediterranean basin. Knowledge of these factors is vital to understanding present forest patterns and predicting future forest dynamics in the Mediterranean mountains. We aimed to analyze and understand how land-use abandonment affected spatial modifications of landscapes in two study areas, 44,000 ha and 60,000 ha, located on the island of Corsica, France, representing a typical Mediterranean environment with chestnut forests. Our approach used land-cover archive documents from 1774, 1913, 1975, and 2000, and human population history, 1770 to present day, to describe landscape patterns following land-use abandonment. This research showed that dramatic changes in landscape at the two study areas were caused by the suspension of human influence and the interruption of traditional farming practices. Over the study period, both study sites showed significant reforestation of shrubland and cultivated areas marked by the presence of Quercus ilex forests (+3.40% yr-1 between 1975 and 2000 and by Pinus pinaster (+3.00% yr-1 between 1975 and 2000 at one study site that had experienced heavy rural exodus. At the same time, areas containing chestnut forests decreased by 50% between 1774 and 2000 (-0.09% yr-1 between 1774 and 1975 and -1.42% yr-1 between 1975 and 2000. Shrubland expansion remained limited at both study sites. Our study highlights the value of small-scale approaches for understanding the ecological consequences of land-use abandonment and present and future land-management decisions. Discussion concludes on the importance of working with long-term series for studies on resilience in social-ecological systems and on the consequences in terms of provision of

  18. [Posttraumatic disturbances in patients with light craniocerebral injury and their correction via various variants of dynamic magnetotherapy].

    Science.gov (United States)

    Cherevashchenko, L A; Moliavchikova, O V; Zhuravlev, M E

    2008-01-01

    Examination of 90 patients in intermediate period of slight craniocerebral injury before and after use of curative technologies with including of dynamic magnetotherapy suboccipitally or transcranially. It is established, that choosing rehabilitation methods, it is necessary to take into consideration clinical manifestation of disease, state of cerebral blood circulation, vegetative nervous system, bioelectrogenesis of cerebrum.

  19. Fixed versus dynamic co-occurrence windows in textrank term weights for information retrieval

    DEFF Research Database (Denmark)

    Lu, Wei; Cheng, Qikai; Lioma, Christina

    2012-01-01

    iteratively is a score for each vertex, i.e. a term weight, that can be used for information retrieval (IR) just like conventional term frequency based term weights. So far, when computing TextRank term weights over co-occurrence graphs, the window of term co-occurrence is always fixed. This work departs from...

  20. Local-scale and short-term herbivore-plant spatial dynamics reflect influences of large-scale climate

    DEFF Research Database (Denmark)

    Forchhammer, Mads Cedergreen; Post, Eric; Berg, Thomas B. G.

    2005-01-01

    The balance of evidence strongly indicates that the ecological repercussions of climatic changes are already apparent in the dynamics of animal and plant populations throughout terrestrial, marine, and aquatic ecosystems. However, while considerable progress has been made in quantifying effects...... of climate change for population and community dynamics. Using comprehensive, spatially replicated data on seasonal plant growth dynamics and seasonal distribution of muskoxen over a seven-year period, we show that interannual variations in the North Atlantic Oscillation affect the seasonal spatial dynamics...... of such climate change on spatiotemporal shifts in distribution, density, and phenology, subtle effects such as intra-annual variation in behavior have been ignored. Yet individual-based assessments of short-term dynamics of species interactions may be critical to improving our understanding of the implications...

  1. Long-Term Dynamic Monitoring of the Historical Masonry FAÇADE: the Case of Palazzo Ducale in Venice, Italy

    Science.gov (United States)

    Noh, J.; Russo, S.

    2017-08-01

    Long-term dynamic monitoring of the masonry façade of Palazzo Ducale known as Doge's palace in Venice, Italy was performed from September 2010 to October 2012. This article demonstrates the results of preliminary analysis on the data set of the first 12-month long monitoring campaign for out-of-plumb dynamic responses of the medieval façade of the monument. The aim of the analysis of the dynamic signals is to validate the data set and investigate dynamic characteristics of the vibration signature of the historical masonry wall in the long-term. Palazzo Ducale is a heavily visited heritage due to its high cultural importance and architectural value. Nevertheless, little is known about the dynamic behaviour of the double-leaf masonry façade. In this study, the dynamic properties of the structure are presented by dynamic identification carried out with the effect of the ambient vibration measured at four different locations on the façade and portico level. The trend and intensity of the vibration at each measurement locations are identified over the year. In addition, the issue on eliminating the noise blended in the signals for reliable analysis are also discussed.

  2. The metabolic dynamics of cartilage explants over a long-term culture period

    Directory of Open Access Journals (Sweden)

    E.K Moo

    2011-01-01

    Full Text Available INTRODUCTION: Although previous studies have been performed on cartilage explant cultures, the generalized dynamics of cartilage metabolism after extraction from the host are still poorly understood due to differences in the experimental setups across studies, which in turn prevent building a complete picture. METHODS: In this study, we investigated the response of cartilage to the trauma sustained during extraction and determined the time needed for the cartilage to stabilize. Explants were extracted aseptically from bovine metacarpal-phalangeal joints and cultured for up to 17 days. RESULTS: The cell viability, cell number, proteoglycan content, and collagen content of the harvested explants were analyzed at 0, 2, 10, and 17 days after explantation. A high percentage of the cartilage explants were found to be viable. The cell density initially increased significantly but stabilized after two days. The proteoglycan content decreased gradually over time, but it did not decrease to a significant level due to leakage through the distorted peripheral collagen network and into the bathing medium. The collagen content remained stable for most of the culture period until it dropped abruptly on day 17. CONCLUSION: Overall, the tested cartilage explants were sustainable over long-term culture. They were most stable from day 2 to day 10. The degradation of the collagen on day 17 did not reach diseased levels, but it indicated the potential of the cultures to develop into degenerated cartilage. These findings have implications for the application of cartilage explants in pathophysiological fields.

  3. Effect of Long—Term Straw Incorporation on Soil Microbial Biomass and C and N Dynamics

    Institute of Scientific and Technical Information of China (English)

    SHENRENFANG; P.C.BROOKES; 等

    1997-01-01

    A study was performed on the long-term effect of straw incorporation on soil microbial biomass C contents,C and N dynamics in both Rothamsted and Woburn soils.The results showed that for both soils,the microbial biomass C contents were significantly different among all the treatments,and followed the sequence in treatments of straw chopped and incorporated into 10 cm(CI10)>straw burnt and incorporated into 10 cm(BI10)>staw chopped and incorporated into 20 cm(CI20)>straw burnt and incorporated into 20 cm(BI20).Laboratory incubation of soils showed that the cumulative CO2 evolution was closely related to the soil microbial biomass C content ,Carbon dioxide evolution rates(CO2-C,μg(g.d)-1)decreased rapidly in the first two weeks' incubation,then decreased more slowly,The initial K2SO4-extractable NH4-N and NO33-N contents were low and similar in all the treatments,and all increased gradually with the incubation time ,However,net N immobiliztion was oberved in chopped treatments for Rothamsted soils durig the first 4 weeks ,Nevertheless,more N mineralization occurred in Treatment CI10 than any other treatment at the end of incubation for both soils .The Woburn soils ,could more easily suffer from the leaching of nitrate because the soils were more pemeable and more N was mineralized during the incubation compared to the Rothamsted soils.

  4. The long-term dynamical evolution of disc-fragmented multiple systems in the Solar Neighborhood

    CERN Document Server

    Li, Yun; Stamatellos, D; Goodwin, S P

    2016-01-01

    The origin of very low-mass hydrogen-burning stars, brown dwarfs, and planetary-mass objects at the low-mass end of the initial mass function is not yet fully understood. Gravitational fragmentation of circumstellar discs provides a possible mechanism for the formation of such low-mass objects. The kinematic and binary properties of very low-mass objects formed through disc fragmentation at early times (< 10 Myr) were discussed in Li et al. (2015). In this paper we extend the analysis by following the long-term evolution of disc-fragmented systems, up to an age of 10 Gyr, covering the ages of the stellar and substellar population in the Galactic field. We find that the systems continue to decay, although the rates at which companions escape or collide with each other are substantially lower than during the first 10 Myr, and that dynamical evolution is limited beyond 1 Gyr. By t = 10 Gyr, about one third of the host stars is single, and more than half have only one companion left. Most of the other systems ...

  5. Effects of long-term variability on projections of twenty-first century dynamic sea level

    Science.gov (United States)

    Bordbar, Mohammad H.; Martin, Thomas; Latif, Mojib; Park, Wonsun

    2015-04-01

    Sea-level rise is one of the most pressing aspects of anthropogenic global warming with far-reaching consequences for coastal societies. However, sea-level rise did and will strongly vary from coast to coast. Here we investigate the long-term internal variability effects on centennial projections of dynamic sea level (DSL), the local departure from the globally averaged sea level. A large ensemble of global warming integrations has been conducted with a climate model, where each realization was forced by identical CO2 increase but started from different atmospheric and oceanic initial conditions. In large parts of the mid- and high latitudes, the ensemble spread of the projected centennial DSL trends is of the same order of magnitude as the globally averaged steric sea-level rise, suggesting that internal variability cannot be ignored when assessing twenty-first-century DSL trends. The ensemble spread is considerably reduced in the mid- to high latitudes when only the atmospheric initial conditions differ while keeping the oceanic initial state identical; indicating that centennial DSL projections are strongly dependent on ocean initial conditions.

  6. Long-Term Internal Variability Effects on Centennial Dynamic Sea Level Projections

    Science.gov (United States)

    Hadi Bordbar, Mohammad; Martin, Thomas; Park, Wonsun; Latif, Mojib

    2015-04-01

    The Earth's surface is warming in response to anthropogenic emissions of greenhouse gases, especially carbon dioxide (CO2). Sea level rise is one of the most pressing aspects of global warming with far-reaching consequences for coastal societies. However, sea level rise did and will strongly vary from coast to coast. Here we investigate the long-term internal variability effects on centennial projections of dynamic sea level (DSL), the local departure from the globally averaged sea level. A large ensemble of global warming integrations was conducted with a climate model, where each ensemble member was forced by identical CO2-increase but started from different atmospheric and oceanic initial conditions taken from an unforced millennial control run. In large parts of the mid- and high latitudes, the ensemble spread of the projected centennial DSL trends is of the same order of magnitude as the globally averaged steric sea level rise, suggesting internal variability cannot be ignored when assessing 21st century DSL changes. This conclusion is also supported by analyzing projections with other climate models. The ensemble spread is strongly reduced in the mid- to high latitudes if only the atmospheric initial conditions are perturbed; suggesting uncertainty in the projected centennial DSL trends there is largely due to the lack of ocean information. Thus climate model projections of regional sea level would benefit from ocean initialization.

  7. Numerical investigation of long-term planform dynamics and stability of river meandering on fluvial floodplains

    Science.gov (United States)

    Xu, Dong; Bai, Yuchuan; Ma, Jianmin; Tan, Yan

    2011-09-01

    A mathematical model for river meandering and floodplain development is presented under the assumption of constant channel width, which combined Johanneson and Parker (1989) linear theory for flows in river bends and a conceptual depositional model from Howard (1992). A new bank erosion model is also developed, which takes into consideration of the nonlinearity in near-bank velocity and the outer bank height. Simulations reproduce the long-term behavior of river meandering and floodplain evolution in a way very similar to their natural processes. Based on the simulation results, stability of river meandering dynamics is discussed and the concept of filtration effect is introduced to highlight meandering rivers' capability to filter out arbitrarily applied planform disturbance. Simulations are also carried out to investigate the influence of the velocity nonlinearity and the outer bank height in bank erosion model, as well as their combinations. Results show that the consideration of velocity nonlinearity in bank erosion model leads to highly upstream-skewing geometry of fully developed river meanders, as well as a slower downstream migration of meander trains. The influence of nonlinearity in bank erosion model is much smaller than the influence of bank height, which reduces the bank migration rate exponentially in the newly introduced bank erosion model. The outer bank height consideration tends to decelerate the downstream migration rate of river meanders and accelerate lateral expansion of the floodplain as well. Consequently, a broader floodplain is generated compared with simulations without bank height considerations.

  8. Patient affect experiencing following therapist interventions in short-term dynamic psychotherapy.

    Science.gov (United States)

    Town, Joel M; Hardy, Gillian E; McCullough, Leigh; Stride, Chris

    2012-01-01

    The aim of this research was to examine the relationship between therapist interventions and patient affect responses in Short-Term Dynamic Psychotherapy (STDP). The Affect Experiencing subscale from the Achievement of Therapeutic Objectives Scale (ATOS) was adapted to measure individual immediate affect experiencing (I-AES) responses in relation to therapist interventions coded within the preceding speaking turn, using the Psychotherapy Interaction Coding (PIC) system. A hierarchical linear modelling procedure was used to assess the change in affect experiencing and the relationship between affect experiencing and therapist interventions within and across segments of therapy. Process data was taken from six STDP cases; in total 24 hours of video-taped sessions were examined. Therapist interventions were found to account for a statistically significant amount of variance in immediate affect experiencing. Higher levels of immediate affect experiencing followed the therapist's use of Confrontation, Clarification and Support compared to Questions, Self-disclosure and Information interventions. Therapist Confrontation interventions that attempted to direct pressure towards either the visceral experience of affect or a patient's defences against feelings led to the highest levels of immediate affect experiencing. The type of therapist intervention accounts for a small but significant amount of the variation observed in a patient's immediate emotional arousal. Empirical findings support clinical theory in STDP that suggests strategic verbal responses promote the achievement of this specific therapeutic objective.

  9. An exponential correction to Starobinsky's inflationary model

    CERN Document Server

    Fabris, Júlio C; Piattella, Oliver F

    2016-01-01

    We analyse $f(R)$ theories of gravity from a dynamical system perspective, showing how the $R^2$ correction in Starobinsky's model plays a crucial role from the viewpoint of the inflationary paradigm. Then, we propose a modification of Starobinsky's model by adding an exponential term in the $f(R)$ Lagrangian. We show how this modification could allow to test the robustness of the model by means of the predictions on the scalar spectral index $n_s$.

  10. Implementing a generic method for bias correction in statistical models using random effects, with spatial and population dynamics examples

    DEFF Research Database (Denmark)

    Thorson, James T.; Kristensen, Kasper

    2016-01-01

    Statistical models play an important role in fisheries science when reconciling ecological theory with available data for wild populations or experimental studies. Ecological models increasingly include both fixed and random effects, and are often estimated using maximum likelihood techniques...... abundance relative to the conventional plug-in estimator, and also gives essentially identical estimates to a sample-based bias-correction estimator. The epsilon-method has been implemented by us as a generic option in the open-source Template Model Builder software, and could be adapted within other....... Quantities of biological or management interest ("derived quantities") are then often calculated as nonlinear functions of fixed and random effect estimates. However, the conventional "plug-in" estimator for a derived quantity in a maximum likelihood mixed-effects model will be biased whenever the estimator...

  11. Adherence and satisfaction of rheumatoid arthritis patients with a long-term intensive dynamic exercise program (RAPIT program).

    NARCIS (Netherlands)

    Munneke, M.; Jong, Z. de; Zwinderman, A.H.; Jansen, A.; Ronday, H.K.; Peter, W.F.H.; Boonman, D.C.G.; Ende, C.H.M. van den; Vliet Vlieland, T.P.M.; Hazes, J.M.W.

    2003-01-01

    OBJECTIVE: To evaluate adherence and satisfaction of patients with rheumatoid arthritis (RA) in a long-term intensive dynamic exercise program. METHODS: A total of 146 RA patients started an intensive (strength and endurance training for 75 minutes, twice a week, for 2 years) exercise program (Rheum

  12. Nonparametric modeling of US interest rate term structure dynamics and implications on the prices of derivative securities

    NARCIS (Netherlands)

    Jiang, GJ

    1998-01-01

    This paper develops a nonparametric model of interest rate term structure dynamics based an a spot rate process that permits only positive interest rates and a market price of interest rate risk that precludes arbitrage opportunities. Both the spot rate process and the market price of interest rate

  13. The SR Approach: a new Estimation Method for Non-Linear and Non-Gaussian Dynamic Term Structure Models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Bent Jesper

    This paper suggests a new and easy approach to estimate linear and non-linear dynamic term structure models with latent factors. We impose no distributional assumptions on the factors and they may therefore be non-Gaussian. The novelty of our approach is to use many observables (yields or bonds p...

  14. Nonparametric modeling of US interest rate term structure dynamics and implications on the prices of derivative securities

    NARCIS (Netherlands)

    Jiang, GJ

    1998-01-01

    This paper develops a nonparametric model of interest rate term structure dynamics based an a spot rate process that permits only positive interest rates and a market price of interest rate risk that precludes arbitrage opportunities. Both the spot rate process and the market price of interest rate

  15. Long-term dynamics in land resource use and the driving forces in the Beressa watershed, highlands of Ethiopia

    NARCIS (Netherlands)

    Amsalu Taye, A.; Stroosnijder, L.; Graaff, de J.

    2007-01-01

    Land degradation in the Ethiopian highlands is considered to be one of the major problems threatening agricultural development and food security in the country. However, knowledge about the forces driving the long-term dynamics in land resources use is limited. This research integrates biophysical i

  16. Numerical Analysis of the Dynamic Behavior of a High Power Salient Pole Synchronous Machine by using a Corrected Model

    Directory of Open Access Journals (Sweden)

    CAMPEANU, A.

    2012-02-01

    Full Text Available In the paper is shown that, by using the circuit theory which operates with lumped parameters, it is possible to derive mathematical models of a high power salient pole synchronous machine (SPSM, that can take into account the basic processes of the machine. It offers results regarding the electromagnetic and mechanical stresses for a given practical application. The quantitative determinations were performed on an 8000 kW synchronous motor. The results of quantitative determinations are of essential interest in the designing stage, for dynamic characteristics and parameters derivation and for constructive solutions to be chosen.

  17. Dephasing of Single-Photon Orbital Angular Momentum Qudit States in Fiber: Limits to Correction via Dynamical Decoupling

    Science.gov (United States)

    Gupta, Manish K.; Dowling, Jonathan P.

    2016-06-01

    We analytically derive a decoherence model for orbital angular momentum states of a photon in a multimode optical fiber and show that the rate of decoherence scales approximately exponentially with l2, where l is the azimuthal mode order. We also show numerically that for large values of l the orbital angular momentum photon state completely dephases. However, for lower values of l the decoherence can be minimized by using dynamical decoupling to allow for qudit high-bandwidth quantum communication and similar applications.

  18. Long-term disturbance dynamics and resilience of tropical peat swamp forests.

    Science.gov (United States)

    Cole, Lydia E S; Bhagwat, Shonil A; Willis, Katherine J

    2015-01-01

    1. The coastal peat swamp forests of Sarawak, Malaysian Borneo, are undergoing rapid conversion, predominantly into oil palm plantations. This wetland ecosystem is assumed to have experienced insignificant disturbance in the past, persisting under a single ecologically-stable regime. However, there is limited knowledge of the past disturbance regime, long-term functioning and fundamentally the resilience of this ecosystem to changing natural and anthropogenic perturbations through time. 2. In this study, long-term ecological data sets from three degraded peatlands in Sarawak were collected to shed light on peat swamp forest dynamics. Fossil pollen and charcoal were counted in each sedimentary sequence to reconstruct vegetation and investigate responses to past environmental disturbance, both natural and anthropogenic. 3. Results demonstrate that peat swamp forest taxa have dominated these vegetation profiles throughout the last c. 2000-year period despite the presence of various drivers of disturbance. Evidence for episodes of climatic variability, predominantly linked to ENSO events, and wildfires is present throughout. However, in the last c. 500 years, burning and indicators of human disturbance have elevated beyond past levels at these sites, concurrent with a reduction in peat swamp forest pollen. 4. Two key insights have been gained through this palaeoecological analysis: (i) peat swamp forest vegetation has demonstrated resilience to disturbance caused by burning and climatic variability in Sarawak in the late Holocene, however (ii) coincident with increased fire combined with human impact c. 500 years ago, these communities started to decline. 5.Synthesis. Sarawak's coastal peat swamps have demonstrated resilience to past natural disturbances, with forest vegetation persisting through episodes of fire and climatic variability. However, palaeoecological data presented here suggest that recent, anthropogenic disturbances are of a greater magnitude, causing

  19. Single-step transepithelial ASLA (SCHWIND with mitomycin-C for the correction of high myopia: long term follow-up

    Directory of Open Access Journals (Sweden)

    Aslanides IM

    2014-12-01

    Full Text Available Ioannis M Aslanides, Panagiotis N Georgoudis, Vasilis D Selimis, Achyut N Mukherjee Emmetropia Mediterranean Eye Institute, Heraklion, Crete, Greece Purpose: We wanted to compare the outcomes of single-step modified transepithelial photorefractive keratectomy (tPRK termed a SCHWIND all surface laser ablation (ASLA versus conventional alcohol-assisted photorefractive keratectomy (PRK and laser-assisted in situ keratomileusis (LASIK for the correction of higher myopia of 6.00 diopters (D or more, in an area with high risk of haze due to high intensity of sunlight.Methods: We used a prospective interventional cohort with matched retrospective control groups. Patients with >6 D myopia and <3.5 D of astigmatism were included. All treatments were performed with the SCHWIND Amaris system using aspheric ablation profiles. Mitomycin C was used in all PRK and ASLA cases. Outcomes were postoperative refraction, visual acuity, stability, and complications. The follow-up period was up to 12 months.Results: In total, 101 eyes were included after exclusions. Mean preoperative spherical equivalent refraction was −7.9 D, −8.2 D, and −7.4 D in the ASLA (n=41, PRK (n=29, and LASIK (n=31 groups. Mean postoperative spherical equivalent at 12 months postoperatively was −0.1 (standard deviation [SD]: 0.34, −0.2 (SD: 0.59, and −0.08 (SD: 0.36 in the ASLA, PRK, and LASIK groups, with 91.4%, 85.7%, and 83.9% within 0.5 D of target, respectively. Refractive outcomes and regression at 12 months did not vary among groups (P>0.05. Mean logMAR (logarithm of the minimum angle of resolution uncorrected distance visual acuity at 12 months was 0.00 (SD: 0.05, 0.06 (SD: 0.1, and 0.05 (SD: 0.09 in the ASLA, PRK, and LASIK groups, with significantly better vision in the tPRK group versus LASIK (P=0.01 and PRK (P=0.01 groups.Conclusion: ASLA (SCHWIND tPRK with mitomycin C for high myopia demonstrates comparable refractive outcomes to LASIK and PRK, with relatively

  20. Dynamic temporal change of cerebral microbleeds: long-term follow-up MRI study.

    Directory of Open Access Journals (Sweden)

    Seung-Hoon Lee

    Full Text Available BACKGROUND: Cerebral microbleeds (MBs are understood as an important radiologic marker of intracerebral hemorrhage. We sought to investigate the temporal changes of MBs and clinical factors associated with the changes using long-term follow-up MRI. METHODS/PRINCIPAL FINDINGS: From October 2002 to July 2006, we prospectively enrolled patients with stroke or transient ischemic attack, and followed-up their brain MRIs with an interval >12 mo. We compared demographic factors, vascular risk factors, laboratory findings, and radiologic factors according to the presence or changes of MBs. A total of 224 patients successfully completed the follow-up examinations (mean, 27 months. Newly developed MBs were noted in 10 patients (6.8% among those without MBs at baseline (n = 148, and in those with MBs at baseline (n = 76, the MB count had decreased in 11 patients (14.5%, and increased in 41 patients (53.9%. The estimated annual rate of change of MB numbers was 0.80 lesions per year in all patients, a value which became greater in those patients who exhibited MBs at baseline (MBs≥5, 5.43 lesions per year. Strokes due to small vessel occlusion and intracerebral hemorrhage, as well as white matter lesions were independently associated with an increased MB count, whereas the highest quartile of low-density lipoprotein (LDL cholesterol was associated with a decreased MB count. CONCLUSION: During the follow-up period, most of MBs showed dynamic temporal change. Symptomatic or asymptomatic small vessel diseases appear to act as risk factors while in contrast, a high level of LDL cholesterol may act as a protective factor against MB increase.

  1. The solenoidal transport option: IFE drivers, near term research facilities, and beam dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.P. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Briggs, R.J. [Science Applications International Corp., Pleasanton, CA (United States)

    1997-09-01

    Solenoidal magnets have been used as the beam transport system in all the high current electron induction accelerators that have been built in the past several decades. They have also been considered for the front end transport system for heavy ion accelerators for Inertial Fusion Energy (IFE) drivers, but this option has received very little attention in recent years. The analysis reported here was stimulated mainly by the recent effort to define an affordable {open_quotes}Integrated Research Experiment{close_quotes} (IRE) that can meet the near term needs of the IFE program. The 1996 FESAC IFE review panel agreed that an integrated experiment is needed to fully resolve IFE heavy ion driver science and technology issues; specifically, {open_quotes}the basic beam dynamics issues in the accelerator, the final focusing and transport issues in a reactor-relevant beam parameter regime, and the target heating phenomenology{close_quotes}. The development of concepts that can meet these technical objectives and still stay within the severe cost constraints all new fusion proposals will encounter is a formidable challenge. Solenoidal transport has a very favorable scaling as the particle mass is decreased (the main reason why it is preferred for electrons in the region below 50 MeV). This was recognized in a recent conceptual study of high intensity induction linac-based proton accelerators for Accelerator Driven Transmutation Technologies, where solenoidal transport was chosen for the front end. Reducing the ion mass is an obvious scaling to exploit in an IRE design, since the output beam voltage will necessarily be much lower than that of a full scale driver, so solenoids should certainly be considered as one option for this experiment as well.

  2. Nonlinear and long-term beam dynamics in low energy storage rings

    Science.gov (United States)

    Papash, A. I.; Smirnov, A. V.; Welsch, C. P.

    2013-06-01

    Electrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged biomolecules, opening up unique research opportunities. However, earlier measurements have shown strong limitations in maximum beam intensity, fast decay of the stored ion current, and reduced beam lifetime. The nature of these effects has not been fully understood and an improved understanding of the physical processes influencing beam motion and stability in such rings is needed. In this paper, a comprehensive study into nonlinear and long-term beam dynamics studies is presented on the examples of a number of existing and planned electrostatic storage rings using the BETACOOL, OPERA-3D, and MAD-X simulation software. A detailed investigation into ion kinetics, under consideration of effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target, is carried out and yields a consistent explanation of the physical effects in a whole class of storage rings. The lifetime, equilibrium momentum spread, and equilibrium lateral spread during collisions with the target are estimated. In addition, the results from experiments at the Test Storage Ring, where a low-intensity beam of CF+ ions at 93keV/u has been shrunk to extremely small dimensions, are reproduced. Based on these simulations, the conditions for stable ring operation with an extremely low-emittance beam are presented. Finally, results from studies into the interaction of 3-30 keV ions with a gas jet target are summarized.

  3. Short-term temporal dynamics of yeast abundance on the tall fescue phylloplane.

    Science.gov (United States)

    Nix, Shannon S; Burpee, Leon L; Jackson, Kimberly L; Buck, James W

    2008-04-01

    Six replicate trials were conducted to determine the short-term temporal dynamics and the effects of foliar applications of nutrients on the phylloplane yeast community of tall fescue (Festuca arundinacea Schreb.). In each trial, 2% sucrose + 0.5% yeast extract solution or sterile deionized water (control) was applied to the experiment plots. Twelve hours post-treatment (at 0600 hours), leaf samples were collected and yeast colony-forming units (cfu) were enumerated by dilution plating. This process was repeated at 1200, 1800, and 2400 hours in each trial. Significant differences were observed between the number of yeast cfu and the time at which the samples were collected. On average, the number of yeast cfu recovered was significantly less at 1800 hours and significantly greatest at 2400 hours when compared with all other sampling times. Averaged over all time intervals, we observed a trend of increased yeast abundance in turf treated with the nutrient solution compared with control treatments. In a separate investigation, atmospheric yeast abundance above the canopy of tall fescue was assessed in the morning (0900) and in the afternoon (1500) using a Thermo Andersen single stage viable particle sampler. In 5 of the 6 trials of this experiment, atmospheric yeast abundance was significantly greater in the morning than in the afternoon. Results suggest the following colonization model: phylloplane yeasts on tall fescue reproduce during the late evening and early morning, stabilize during the late morning and early afternoon through exchange of immigrants and emigrants, and decline during the late afternoon and (or) early evening.

  4. Long term picoplankton dynamics in a warm-monomictic, tropical high altitude lake

    Directory of Open Access Journals (Sweden)

    Alfonso LUGO VÁZQUEZ

    2009-08-01

    Full Text Available Long term analyses of the microbial loop, centred on the picoplankton dynamics, were carried out over a five-year (1998 to 2002 period in Lake Alchichica (Puebla, Mexico, a high altitude tropical athalassohaline lake. The hydrodynamics of the lake followed a warm-monomictic pattern with mixing at a minimum temperature during the early dry season while the stratification was pronounced in the late dry season and throughout the rainy season; anoxic conditions in the hypolimnion lasted <9 months. The annual mean concentrations of chlorophyll-a were below 4 μg L-1 in 1998, 1999 and 2001, however, 6.1 and 5.2 μg L-1 in 2000 and 2002, respectively. Total picoplankton, TPP, displayed a temporal pattern that followed the mixing-stratification cycle. The highest TPP values (the whole water column ≥5×106 cells mL-1 were found during mixing and early stratification (January-March. The minimum numbers were present during late stratification (October-November. The maximum TPP numbers were observed within the layer 0-20 m, which corresponded to the epilimnion during the stratification period. Neither the thermocline nor the deep chlorophyll maximum showed an elevated TPP concentration. In the hypolimnion, TPP numbers were low (frequently <1×106 cells mL-1 apparently as a result of the long period of anoxia. Notwithstanding autotrophic picoplankton (APP contributed even ≥30% of TPP (2001 to 2002; no significant correlation was found between TPP and chlorophyll-a.

  5. Nonlinear and long-term beam dynamics in low energy storage rings

    Directory of Open Access Journals (Sweden)

    A. I. Papash

    2013-06-01

    Full Text Available Electrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged biomolecules, opening up unique research opportunities. However, earlier measurements have shown strong limitations in maximum beam intensity, fast decay of the stored ion current, and reduced beam lifetime. The nature of these effects has not been fully understood and an improved understanding of the physical processes influencing beam motion and stability in such rings is needed. In this paper, a comprehensive study into nonlinear and long-term beam dynamics studies is presented on the examples of a number of existing and planned electrostatic storage rings using the BETACOOL, OPERA-3D, and MAD-X simulation software. A detailed investigation into ion kinetics, under consideration of effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target, is carried out and yields a consistent explanation of the physical effects in a whole class of storage rings. The lifetime, equilibrium momentum spread, and equilibrium lateral spread during collisions with the target are estimated. In addition, the results from experiments at the Test Storage Ring, where a low-intensity beam of CF^{+} ions at 93  keV/u has been shrunk to extremely small dimensions, are reproduced. Based on these simulations, the conditions for stable ring operation with an extremely low-emittance beam are presented. Finally, results from studies into the interaction of 3–30 keV ions with a gas jet target are summarized.

  6. Quantum Error-Correction-Enhanced Magnetometer Overcoming the Limit Imposed by Relaxation.

    Science.gov (United States)

    Herrera-Martí, David A; Gefen, Tuvia; Aharonov, Dorit; Katz, Nadav; Retzker, Alex

    2015-11-13

    When incorporated in quantum sensing protocols, quantum error correction can be used to correct for high frequency noise, as the correction procedure does not depend on the actual shape of the noise spectrum. As such, it provides a powerful way to complement usual refocusing techniques. Relaxation imposes a fundamental limit on the sensitivity of state of the art quantum sensors which cannot be overcome by dynamical decoupling. The only way to overcome this is to utilize quantum error correcting codes. We present a superconducting magnetometry design that incorporates approximate quantum error correction, in which the signal is generated by a two qubit Hamiltonian term. This two-qubit term is provided by the dynamics of a tunable coupler between two transmon qubits. For fast enough correction, it is possible to lengthen the coherence time of the device beyond the relaxation limit.

  7. Space-based passive microwave soil moisture retrievals and the correction for a dynamic open water fraction

    Directory of Open Access Journals (Sweden)

    B. T. Gouweleeuw

    2012-06-01

    Full Text Available The large observation footprint of low-frequency satellite microwave emissions complicates the interpretation of near-surface soil moisture retrievals. While the effect of sub-footprint lateral heterogeneity is relatively limited under unsaturated conditions, open water bodies (if not accounted for cause a strong positive bias in the satellite-derived soil moisture retrieval. This bias is generally assumed static and associated with large, continental lakes and coastal areas. Temporal changes in the extent of smaller water bodies as small as a few percent of the sensor footprint size, however, can cause significant and dynamic biases. We analysed the influence of such small open water bodies on near-surface soil moisture products derived from actual (non-synthetic data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E for three areas in Oklahoma, USA. Differences between on-ground observations, model estimates and AMSR-E retrievals were related to dynamic estimates of open water fraction, one retrieved from a global daily record based on higher frequency AMSR-E data, a second derived from the Moderate Resolution Imaging Spectroradiometer (MODIS and a third through inversion of the radiative transfer model, used to retrieve soil moisture. The comparison demonstrates the presence of relatively small areas (<0.05 of open water in or near the sensor footprint, possibly in combination with increased, below-critical vegetation density conditions (optical density <0.8, which contribute to seasonally varying biases in excess of 0.2 (m3 m−3 soil water content. These errors need to be addressed, either through elimination or accurate characterisation, if the soil moisture retrievals are to be used effectively in a data assimilation scheme.

  8. Linear versus Nonlinear Filtering with Scale-Selective Corrections for Balanced Dynamics in a Simple Atmospheric Model

    KAUST Repository

    Subramanian, Aneesh C.

    2012-11-01

    This paper investigates the role of the linear analysis step of the ensemble Kalman filters (EnKF) in disrupting the balanced dynamics in a simple atmospheric model and compares it to a fully nonlinear particle-based filter (PF). The filters have a very similar forecast step but the analysis step of the PF solves the full Bayesian filtering problem while the EnKF analysis only applies to Gaussian distributions. The EnKF is compared to two flavors of the particle filter with different sampling strategies, the sequential importance resampling filter (SIRF) and the sequential kernel resampling filter (SKRF). The model admits a chaotic vortical mode coupled to a comparatively fast gravity wave mode. It can also be configured either to evolve on a so-called slow manifold, where the fast motion is suppressed, or such that the fast-varying variables are diagnosed from the slow-varying variables as slaved modes. Identical twin experiments show that EnKF and PF capture the variables on the slow manifold well as the dynamics is very stable. PFs, especially the SKRF, capture slaved modes better than the EnKF, implying that a full Bayesian analysis estimates the nonlinear model variables better. The PFs perform significantly better in the fully coupled nonlinear model where fast and slow variables modulate each other. This suggests that the analysis step in the PFs maintains the balance in both variables much better than the EnKF. It is also shown that increasing the ensemble size generally improves the performance of the PFs but has less impact on the EnKF after a sufficient number of members have been used.

  9. Objective evaluation of the correction by non-rigid registration of abdominal organ motion in low-dose 4D dynamic contrast-enhanced CT

    Science.gov (United States)

    Piper, Jim; Ikeda, Yoshihiro; Fujisawa, Yasuko; Ohno, Yoshiharu; Yoshikawa, Takeshi; O'Neil, Alison; Poole, Ian

    2012-03-01

    We objectively evaluate a straightforward registration method for correcting respiration-induced movement of abdominal organs in CT perfusion studies by measuring the distributions of alignment errors between corresponding landmark pairs. We introduce the concept and describe the advantages of using the surface-normal component of distance between pairs of corresponding landmarks selected so that their surface normal is in one of the three coordinate axis directions, and show that such landmarks can be precisely placed with respect to the surface normal. Using a large population of landmark pairs on a substantial quantity of 4D dynamic contrast-enhanced CT volume data, we quantify the average alignment errors of abdominal organs that remain uncorrected by registration.

  10. The accurate calculation of the band gap of liquid water by means of GW corrections applied to plane-wave density functional theory molecular dynamics simulations.

    Science.gov (United States)

    Fang, Changming; Li, Wun-Fan; Koster, Rik S; Klimeš, Jiří; van Blaaderen, Alfons; van Huis, Marijn A

    2015-01-07

    Knowledge about the intrinsic electronic properties of water is imperative for understanding the behaviour of aqueous solutions that are used throughout biology, chemistry, physics, and industry. The calculation of the electronic band gap of liquids is challenging, because the most accurate ab initio approaches can be applied only to small numbers of atoms, while large numbers of atoms are required for having configurations that are representative of a liquid. Here we show that a high-accuracy value for the electronic band gap of water can be obtained by combining beyond-DFT methods and statistical time-averaging. Liquid water is simulated at 300 K using a plane-wave density functional theory molecular dynamics (PW-DFT-MD) simulation and a van der Waals density functional (optB88-vdW). After applying a self-consistent GW correction the band gap of liquid water at 300 K is calculated as 7.3 eV, in good agreement with recent experimental observations in the literature (6.9 eV). For simulations of phase transformations and chemical reactions in water or aqueous solutions whereby an accurate description of the electronic structure is required, we suggest to use these advanced GW corrections in combination with the statistical analysis of quantum mechanical MD simulations.

  11. [Microalbuminuria as a marker of endothelial dysfunction in the long-term follow-up patients after surgical correction of aortic coarctation].

    Science.gov (United States)

    Volkova, N I; Lazoryshynets, V V

    2013-06-01

    1170 patients after surgical correction of aortic coarctation during the period from 1988 to 2002 were studied. The median period of medical supervision after coarctation repair was 13,8 years, maximum age - 24 years. For diagnostics of the Microalbuminuria (MAU) it were used the special test-strings Microalbu PHAN (PLIVA-Lachema Diagnostica). MAU were discovered in 62.6% of and 34.9% of normotesive patients. Credible decrease of MAU of hypertensive patients with corrected coarctation of the aorta were defined after 3 months-long treatment by Losartan.

  12. Long-term Soil C and N Dynamics in Response to Enhanced Wind Erosion in Semiarid Grassland, Using CENTURY Model

    Science.gov (United States)

    Li, J.; Okin, G. S.; Alavrez, L.; Epstein, H.

    2007-12-01

    Recent studies show that enhanced wind erosion changes soil carbon (C) and nitrogen (N) cycling in desert grasslands of southern New Mexico. However, long-term effects at the scale of decades to centuries are less known, especially under the conditions of drought, directional changes in climate, and land use pressures. Additionally, previous studies have focused on the isolated response of soil C and N, with little understanding of their interactions and differential response of other sub-pools. Using CENTURY, a process-based biogeochemical model, we evaluate the potential impacts of enhanced wind erosion on the long-term dynamics of C and N in the Jornada Experimental Range, southern New Mexico. We find that enhanced wind erosion does have a significant effect on long-term dynamics of C and N that are similar to the short-term dynamics observed in a field experiment at Jornada. The relationships between pools of C and N, levels of wind erosion and vegetation cover reduction as well as the mechanisms by which wind erosion changes C and N cycling in desert grasslands are discussed.

  13. Construction of diabatic Hamiltonian matrix from ab initio calculated molecular symmetry adapted nonadiabatic coupling terms and nuclear dynamics for the excited states of Na3 cluster.

    Science.gov (United States)

    Mukherjee, Saikat; Bandyopadhyay, Sudip; Paul, Amit Kumar; Adhikari, Satrajit

    2013-04-25

    We present the molecular symmetry (MS) adapted treatment of nonadiabatic coupling terms (NACTs) for the excited electronic states (2(2)E' and 1(2)A1') of Na3 cluster, where the adiabatic potential energy surfaces (PESs) and the NACTs are calculated at the MRCI level by using an ab initio quantum chemistry package (MOLPRO). The signs of the NACTs at each point of the configuration space (CS) are determined by employing appropriate irreducible representations (IREPs) arising due to MS group, and such terms are incorporated into the adiabatic to diabatic transformation (ADT) equations to obtain the ADT angles. Since those sign corrected NACTs and the corresponding ADT angles demonstrate the validity of curl condition for the existence of three-state (2(2)E' and 1(2)A1') sub-Hilbert space, it becomes possible to construct the continuous, single-valued, symmetric, and smooth 3 × 3 diabatic Hamiltonian matrix. Finally, nuclear dynamics has been carried out on such diabatic surfaces to explore whether our MS-based treatment of diabatization can reproduce the pattern of the experimental spectrum for system B of Na3 cluster.

  14. Bodily Tides near the 1:1 Spin-Orbit Resonance: Correction to Goldreich’s Dynamical Model

    Science.gov (United States)

    2012-01-01

    Efroimsky 2012a,b) to read as U (r) = −GM∗sec ∞∑ l=2 kl R 2l+1 r l+1 r ∗ l+1 l∑ m=0 (l − m)! (l + m)! (2− δ0m) Plm (sin φ) Plm (sin φ ∗) cosm(λ− λ∗), (1...associated Legendre functions Plm (x) (termed associated Legendre polynomials when their argument is sine or cosine of some angle) are introduced as in Kaula...for a nonnegative m, as Plm (x) = ( 1 − x2 )m/2 dm dxm Pl (x) and P m l (x) = (−1)m ( 1 − x2 )m/2 dm dxm Pl (x), so that Plm (x) = (−1)m Pml (x). The

  15. Is correction necessary when clinically determining quantitative cerebral perfusion parameters from multi-slice dynamic susceptibility contrast MR studies?

    Science.gov (United States)

    Salluzzi, M.; Frayne, R.; Smith, M. R.

    2006-01-01

    Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies. Preliminary results associated with this paper were presented at ISMRM 12th Scientific Meeting and Exhibition, Kyoto, Japan, 2004.

  16. Is correction necessary when clinically determining quantitative cerebral perfusion parameters from multi-slice dynamic susceptibility contrast MR studies?

    Science.gov (United States)

    Salluzzi, M; Frayne, R; Smith, M R

    2006-01-21

    Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies.

  17. Minor long-term effects of ultraviolet-B radiation on methane dynamics of a subarctic fen in Northern Finland

    DEFF Research Database (Denmark)

    Mörsky, Sami K.; Haapala, Jaana K.; Rinnan, Riikka;

    2012-01-01

    The effects of elevated ultraviolet-B (UVB) radiation on methane dynamics was studied in a natural fen in Northern Finland for three growing seasons (2003–2005). This is the first in situ study on the effects of elevated UV-B radiation on methane dynamics in a natural fen. The experimental setup....... The results emphasize the need for long-term field studies under moderately enhanced exposures to estimate whether the function and feedbacks of mire ecosystems change under increased UV-B radiation....

  18. The response of future projections of the North American monsoon when combining dynamical downscaling and bias correction of CCSM4 output

    Science.gov (United States)

    Meyer, Jonathan D. D.; Jin, Jiming

    2016-09-01

    A 20-km regional climate model (RCM) dynamically downscaled the Community Climate System Model version 4 (CCSM4) to compare 32-year historical and future "end-of-the-century" climatologies of the North American Monsoon (NAM). CCSM4 and other phase 5 Coupled Model Intercomparison Project models have indicated a delayed NAM and overall general drying trend. Here, we test the suggested mechanism for this drier NAM where increasing atmospheric static stability and reduced early-season evapotranspiration under global warming will limit early-season convection and compress the mature-season of the NAM. Through our higher resolution RCM, we found the role of accelerated evaporation under a warmer climate is likely understated in coarse resolution models such as CCSM4. Improving the representation of mesoscale interactions associated with the Gulf of California and surrounding topography produced additional surface evaporation, which overwhelmed the convection-suppressing effects of a warmer troposphere. Furthermore, the improved land-sea temperature gradient helped drive stronger southerly winds and greater moisture transport. Finally, we addressed limitations from inherent CCSM4 biases through a form of mean bias correction, which resulted in a more accurate seasonality of the atmospheric thermodynamic profile. After bias correction, greater surface evaporation from average peak GoC SSTs of 32 °C compared to 29 °C from the original CCSM4 led to roughly 50 % larger changes to low-level moist static energy compared to that produced by the downscaled original CCSM4. The increasing destabilization of the NAM environment produced onset dates that were one to 2 weeks earlier in the core of the NAM and northern extent, respectively. Furthermore, a significantly more vigorous NAM signal was produced after bias correction, with >50 mm month-1 increases to the June-September precipitation found along east and west coasts of Mexico and into parts of Texas. A shift towards more

  19. Calculation of radar signal delays in the vicinity of the Sun due to the contribution of a Yukawa correction term in the gravitational potential

    Science.gov (United States)

    Haranas, Ioannis; Ragos, Omiros

    2011-07-01

    There has been a renewed interest in the recent years in the possibility of deviations from the predictions of Newton's "inverse-square law" of universal gravitation. One of the reasons for renewing this interest lies in various theoretical attempts to construct a unified elementary particle theory, in which there is a natural prediction of new forces over macroscopic distances. Therefore the existence of such a force would only coexist with gravity, and in principle could only be detected as a deviation from the inverse square law, or in the "universality of free fall" experiments. New experimental techniques such that of Sagnac interferometry can help explore the range of the Yukawa correction λ≥1014 m where such forces might be present. It may be, that future space missions might be operating in this range which has been unexplored for very long time. To study the effect of the Yukawa correction to the gravitational potential and its corresponding signal delay in the vicinity of the Sun, we use a spherically symmetric modified space time metric where the Yukawa correction its added to the gravitational potential. Next, the Yukawa correction contribution to the signal delay is evaluated. In the case where the distance of closest approach is much less than the range λ, it results to a signal time delay that satisfies the relation t( b< λ)≅37.7 t( b= λ).

  20. Disturbance frequency and vertical distribution of seeds affect long-term population dynamics: a mechanistic seed bank model.

    Science.gov (United States)

    Eager, Eric Alan; Haridas, Chirakkal V; Pilson, Diana; Rebarber, Richard; Tenhumberg, Brigitte

    2013-08-01

    Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.

  1. Shape-based motion correction in dynamic contrast-enhanced MRI for quantitative assessment of renal function.

    Science.gov (United States)

    Liu, Wenyang; Sung, Kyunghyun; Ruan, Dan

    2014-12-01

    To incorporate a newly developed shape-based motion estimation scheme into magnetic resonance urography (MRU) and verify its efficacy in facilitating quantitative functional analysis. The authors propose a motion compensation scheme in MRU that consists of three sequential modules: MRU image acquisition, motion compensation, and quantitative functional analysis. They designed two sets of complementary experiments to evaluate the performance of the proposed method. In the first experiment, dynamic contrast enhanced (DCE) MR images were acquired from three sedated subjects, from which clinically valid estimates were derived and served as the "ground truth." Physiologically sound motion was then simulated to synthesize image sequences influenced by respiratory motion. Quantitative assessment and comparison were performed on functional estimates of Patlak number, glomerular filtration rate, and Patlak differential renal function without and with motion compensation against the ground truth. In the second experiment, the authors acquired a temporal series of noncontrast MR images under free breathing from a healthy adult subject. The performance of the proposed method on compensating real motion was evaluated by comparing the standard deviation of the obtained temporal intensity curves before and after motion compensation. On DCE-MR images with simulated motion, the generated relative enhancement curves exhibited large perturbations and the Patlak numbers of the left and right kidney were significantly underestimated up to 35% and 34%, respectively, compared with the ground truth. After motion compensation, the relative enhancement curves exhibited much less perturbations and Patlak estimation errors reduced within 3% and 4% for the left and right kidneys, respectively. On clinical free-breathing MR images, the temporal intensity curves exhibited significantly reduced variations after motion compensation, with standard deviation decreased from 30.3 and 38.2 to 8.3 and

  2. Short term outcome of posterior dynamic stabilization system in degenerative lumbar diseases

    Directory of Open Access Journals (Sweden)

    Mingyuan Yang

    2014-01-01

    Conclusion: Dynamic stabilization system treating lumbar degenerative disease showed clinical benefits with motion preservation of the operated segments, but does not have the significant advantage on motion preservation at adjacent segments, to avoid the degeneration of adjacent intervertebral disk.

  3. Study on Dynamic Response Measurement of the Submarine Pipeline by Full-Term FBG Sensors

    Directory of Open Access Journals (Sweden)

    Jinghai Zhou

    2014-01-01

    Full Text Available The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement.

  4. Hematopoietic stem cell gene therapy for adenosine deaminase-deficient severe combined immunodeficiency leads to long-term immunological recovery and metabolic correction.

    Science.gov (United States)

    Gaspar, H Bobby; Cooray, Samantha; Gilmour, Kimberly C; Parsley, Kathryn L; Zhang, Fang; Adams, Stuart; Bjorkegren, Emma; Bayford, Jinhua; Brown, Lucinda; Davies, E Graham; Veys, Paul; Fairbanks, Lynette; Bordon, Victoria; Petropoulou, Theoni; Petropolou, Theoni; Kinnon, Christine; Thrasher, Adrian J

    2011-08-24

    Genetic defects in the purine salvage enzyme adenosine deaminase (ADA) lead to severe combined immunodeficiency (SCID) with profound depletion of T, B, and natural killer cell lineages. Human leukocyte antigen-matched allogeneic hematopoietic stem cell transplantation (HSCT) offers a successful treatment option. However, individuals who lack a matched donor must receive mismatched transplants, which are associated with considerable morbidity and mortality. Enzyme replacement therapy (ERT) for ADA-SCID is available, but the associated suboptimal correction of immunological defects leaves patients susceptible to infection. Here, six children were treated with autologous CD34-positive hematopoietic bone marrow stem and progenitor cells transduced with a conventional gammaretroviral vector encoding the human ADA gene. All patients stopped ERT and received mild chemotherapy before infusion of gene-modified cells. All patients survived, with a median follow-up of 43 months (range, 24 to 84 months). Four of the six patients recovered immune function as a result of engraftment of gene-corrected cells. In two patients, treatment failed because of disease-specific and technical reasons: Both restarted ERT and remain well. Of the four reconstituted patients, three remained off enzyme replacement. Moreover, three of these four patients discontinued immunoglobulin replacement, and all showed effective metabolic detoxification. All patients remained free of infection, and two cleared problematic persistent cytomegalovirus infection. There were no adverse leukemic side effects. Thus, gene therapy for ADA-SCID is safe, with effective immunological and metabolic correction, and may offer a viable alternative to conventional unrelated donor HSCT.

  5. 动力触探杆长适应性及其修正试验%Adaptation and Correction of Dynamic Penetration Rod Length

    Institute of Scientific and Technical Information of China (English)

    李会中; 郭飞; 傅少君; 郝文忠; 李志

    2016-01-01

    西部地区河床深厚覆盖层勘探取样及工程特性是水电工程地质勘察中常遇技术难题,动力触探(dynamic penetration test, DPT)因操作简单、适用土类多而成为西部地区河床覆盖层原位测试首选方法。现行规范仅给出了20 m 杆长范围的修正方法,但对超此范围重型、超重型动力触探杆长适用性及修正问题,长期以来业内则颇多争议却少有研究。鉴于此,利用现场试验与数值模拟相结合,通过对动力触探试验杆上各测点应变现场实测并得到各测点应力分布,再利用 LS-DYNA 软件进行反演分析并确定相关计算参数,而后进行杆长25 m、40 m、60 m、80 m、120 m 的数值模拟计算得到了杆长适用范围及修正系数。试验研究方法及成果可供类似问题研究与深厚覆盖层地区工程勘察借鉴或参考。%In the geotechnical investigation of hydropower projects in western China,exploratory sampling and engineering property research are challenging on account of the thick overburden on the riverbed.The dynamic penetration test(DPT)has become the preferred method of in-situ tests for the river overburden layers in western China due to its simple operation and ap-plicability for different soil types.The current standard only provides a correction method for the rod length within 20 m.For the problems of adaptation and correction of heavy and extra-heavy dynamic penetration rod length,there is always much con-troversy but rare research for a long time.To address this issue,a study is conducted,involving the following procedures. Firstly,combined with the field test and numerical simulation,the stress value of each monitoring point is obtained by monito-ring the rod of field DPT.Then,LS-DYNA software is used for inverse analysis and relevant parameters are determinined. Lastly,different rod lengths of DPT,such as 25 m,40 m,60 m,80 m and 120 m,are simulated,and the adaptation and cor-rection of rod length are

  6. Long-term dynamic behavior of monopile supported offshore wind turbines in sand

    Directory of Open Access Journals (Sweden)

    Lu-Qing Yu

    2015-03-01

    Full Text Available The complexity of the loads acting on the offshore wind turbines (OWTs structures and the significance of investigation on structure dynamics are explained. Test results obtained from a scaled wind turbine model are also summarized. The model is supported on monopile, subjected to different types of dynamic loading using an innovative out of balance mass system to apply cyclic/dynamic loads. The test results show the natural frequency of the wind turbine structure increases with the number of cycles, but with a reduced rate of increase with the accumulation of soil strain level. The change is found to be dependent on the shear strain level in the soil next to the pile which matches with the expectations from the element tests of the soil. The test results were plotted in a non-dimensional manner in order to be scaled to predict the prototype consequences using element tests of a soil using resonant column apparatus.

  7. Origin and Dynamical Evolution of Neptune Trojans - II: Long Term Evolution

    CERN Document Server

    Lykawka, Patryk Sofia; Jones, Barrie W; Mukai, Tadashi

    2010-01-01

    We present results examining the fate of the Trojan clouds produced in our previous work. We find that the stability of Neptunian Trojans seems to be strongly correlated to their initial post-migration orbital elements, with those objects that survive as Trojans for billions of years displaying negligible orbital evolution. The great majority of these survivors began the integrations with small eccentricities (e 20{\\deg}. Dynamical integrations of the currently observed Trojans show that five out of the seven are dynamically stable on 4 Gyr timescales, while 2001 QR322, exhibits significant dynamical instability. The seventh Trojan object, 2008 LC18, has such large orbital uncertainties that only future studies will be able to determine its stability.

  8. Differentiation of brain abscesses from glioblastomas and metastatic brain tumors: comparisons of diagnostic performance of dynamic susceptibility contrast-enhanced perfusion MR imaging before and after mathematic contrast leakage correction.

    Directory of Open Access Journals (Sweden)

    Cheng Hong Toh

    Full Text Available PURPOSE: To compare the diagnostic performance of dynamic susceptibility contrast-enhanced perfusion MRI before and after mathematic contrast leakage correction in differentiating pyogenic brain abscesses from glioblastomas and/or metastatic brain tumors. MATERIALS AND METHODS: Cerebral blood volume (CBV, leakage-corrected CBV and leakage coefficient K2 were measured in enhancing rims, perifocal edema and contralateral normal appearing white matter (NAWM of 17 abscesses, 19 glioblastomas and 20 metastases, respectively. The CBV and corrected CBV were normalized by dividing the values in the enhancing rims or edema to those of contralateral NAWM. For each study group, a paired t test was used to compare the K2 of the enhancing rims or edema with those of NAWM, as well as between CBV and corrected CBV of the enhancing rims or edema. ANOVA was used to compare CBV, corrected CBV and K2 among three lesion types. The diagnostic performance of CBV and corrected CBV was assessed with receiver operating characteristic (ROC curve analysis. RESULTS: The CBV and correction CBV of enhancing rim were 1.45±1.17 and 1.97±1.01 for abscesses, 3.85±2.19 and 4.39±2.33 for glioblastomas, and 2.39±0.90 and 2.97±0.78 for metastases, respectively. The CBV and corrected CBV in the enhancing rim of abscesses were significantly lower than those of glioblastomas and metastases (P = 0.001 and P = 0.007, respectively. In differentiating abscesses from glioblastomas and metastases, the AUC values of corrected CBV (0.822 were slightly higher than those of CBV (0.792. CONCLUSIONS: Mathematic leakage correction slightly increases the diagnostic performance of CBV in differentiating pyogenic abscesses from necrotic glioblastomas and cystic metastases. Clinically, DSC perfusion MRI may not need mathematic leakage correction in differentiating abscesses from glioblastomas and/or metastases.

  9. 带旋转修正的弹簧-TFI混合动网格方法%Spring-TFI Hybrid Dynamic Mesh Method with Rotation Correction

    Institute of Scientific and Technical Information of China (English)

    张兵; 韩景龙

    2011-01-01

    Problems of orthogonal properties become more serious when the traditional transfinite interpolation (TFI) dynamic mesh method is employed for large deformations. Based on an analysis of the geometric relationship and interpolation features, an improvement for the present TFI method is proposed with a rotation correction. A new spring-TFI hybrid dynamic mesh method is developed for a structured mesh. First, each block of the computation domain is divided into several sub-blocks. Then, a spring network which connects the corners of all sub-blocks is established to smooth the mesh by means of spring analysis. Finally, a modified TFI method is used for calculating the inner deformations of the sub-blocks. Computational results of typical two and three dimensional viscous grids indicate that good orthogonal and smoothing properties can be achieved by rotation correction for large mesh deformations. In addition, the computational efficiency is slightly decreased than the traditional TFI method, but improved by 1 or 2 orders of magnitude when compared with the spring analogy method.%网格存在大变形时,传统的超限插值(TFI)动网格方法易于引起网格正交性问题.依据几何关系并考虑其插值特点,提出了一种带旋转修正的TFI动网格方法.对结构网格块进行分块,在子块角点间建立弹簧元,并基于弹簧类比法计算角点位移;子网格内部结点位移采用修正后的TFI动网格方法进行计算,从而形成具有弹簧-TFI混合特征的动网格新方法.以典型二维及三维黏性网格为例进行方法的有效性研究.结果表明,在显著大变形情况下,引入旋转修正得到了正交性和光顺性良好的变形网格.另外,该方法的计算效率较传统TFI动网格方法有所降低,但相比弹簧方法提高1到2个量级.

  10. Field estimates of gravity terrain corrections and Y2K-compatible method to convert from gravity readings with multiple base stations to tide- and long-term drift-corrected observations

    Science.gov (United States)

    Plouff, Donald

    2000-01-01

    Gravity observations are directly made or are obtained from other sources by the U.S. Geological Survey in order to prepare maps of the anomalous gravity field and consequently to interpret the subsurface distribution of rock densities and associated lithologic or geologic units. Observations are made in the field with gravity meters at new locations and at reoccupations of previously established gravity "stations." This report illustrates an interactively-prompted series of steps needed to convert gravity "readings" to values that are tied to established gravity datums and includes computer programs to implement those steps. Inasmuch as individual gravity readings have small variations, gravity-meter (instrument) drift may not be smoothly variable, and acommodations may be needed for ties to previously established stations, the reduction process is iterative. Decision-making by the program user is prompted by lists of best values and graphical displays. Notes about irregularities of topography, which affect the value of observed gravity but are not shown in sufficient detail on topographic maps, must be recorded in the field. This report illustrates ways to record field notes (distances, heights, and slope angles) and includes computer programs to convert field notes to gravity terrain corrections. This report includes approaches that may serve as models for other applications, for example: portrayal of system flow; style of quality control to document and validate computer applications; lack of dependence on proprietary software except source code compilation; method of file-searching with a dwindling list; interactive prompting; computer code to write directly in the PostScript (Adobe Systems Incorporated) printer language; and high-lighting the four-digit year on the first line of time-dependent data sets for assured Y2K compatibility. Computer source codes provided are written in the Fortran scientific language. In order for the programs to operate, they first

  11. The Behavioral Type of a Top Predator Drives the Short-Term Dynamic of Intraguild Predation.

    Science.gov (United States)

    Michalko, Radek; Pekár, Stano

    2017-03-01

    Variation in behavior among individual top predators (i.e., the behavioral type) can strongly shape pest suppression in intraguild predation (IGP). However, the effect of a top predator's behavioral type-namely, foraging aggressiveness (number of killed divided by prey time) and prey choosiness (preference degree for certain prey type)-on the dynamic of IGP may interact with the relative abundances of top predator, mesopredator, and pest. We investigated the influence of the top predator's behavioral type on the dynamic of IGP in a three-species system with a top predator spider, a mesopredator spider, and a psyllid pest using a simulation model. The model parameters were estimated from laboratory experiments and field observations. The top predator's behavioral type altered the food-web dynamics in a context-dependent manner. The system with an aggressive/nonchoosy top predator, without prey preferences between pest and mesopredator, suppressed the pest more when the top predator to mesopredator abundance ratio was high. In contrast, the system with a timid/choosy top predator that preferred the pest to the mesopredator was more effective when the ratio was low. Our results show that the behavioral types and abundances of interacting species need to be considered together when studying food-web dynamics, because they evidently interact. To improve biocontrol efficiency of predators, research on the alteration of their behavioral types is needed.

  12. Port-Based Modeling of Dynamic Systems in Terms of Bond Graphs

    NARCIS (Netherlands)

    Breedveld, Peter C.; Troch, I.; Breitenecker, F.

    2006-01-01

    Port-based modeling of dynamic systems is the topic of the first chapter of the book that will be one of the main results of the European project ‘Geometric Network Modeling and Control of Complex Physical Systems’ (GEOPLEX, IST-2001-34166, Key Action, Action line KAIV: Essential Technologies and In

  13. Long-term dynamics of Coxiella burnetii in farmed red deer (Cervus elaphus

    Directory of Open Access Journals (Sweden)

    David eGonzález-Barrio

    2015-12-01

    Full Text Available Several aspects of the dynamics of Coxiella burnetii that are relevant for the implementation of control strategies in ruminant herds with endemic Q-fever are unknown. We designed a longitudinal study to monitor the dynamics of exposure to C. burnetii in a red deer herd with endemic infection in order to allow the design of Q fever specific control approaches. Other relevant aspects of the dynamics of C. burnetii - the effect of herd immune status, age, season and early infection on exposure, the average half-life of antibodies, the presence and duration of maternal humoral immunity and the age of first exposure - were analysed. The dynamics of C. burnetii in deer herds seems to be modulated by host herd and host individual factors and by particular host life history traits. Red deer females become exposed to C. burnetii at the beginning of their second year since maternal antibodies protect them after birth and during the main pathogen shedding season - at the end of spring-early summer. Infection pressure varies between years, probably associated to herd immunity effects, determining inter-annual variation in the risk of exposure. These results suggest that any strategy applied to control C. burnetii in deer herds should be designed to induce immunity in their first year of life immediately after losing maternal antibodies. The short average life of C. burnetii antibodies suggests that any protection based upon humoral immunity would require re-vaccination every 6 months.

  14. Short-term motor learning of dynamic balance control in children with probable Developmental Coordination Disorder

    NARCIS (Netherlands)

    Jelsma, Dorothee; Ferguson, Gilian D.; Smits-Engelsman, Bouwien C.M.; Geuze, Reint H.

    2015-01-01

    Purpose: To explore the differences in learning a dynamic balance task between children with and without probable Developmental Coordination Disorder (p-DCD) from different cultural backgrounds. Participants: Twenty-eight Dutch children with DCD (p-DCD-NL), a similar group of 17 South African childr

  15. Field theory of bicritical and tetracritical points. IV. Critical dynamics including reversible terms.

    Science.gov (United States)

    Folk, R; Holovatch, Yu; Moser, G

    2012-02-01

    This article concludes a series of papers [Folk, Holovatch, and Moser, Phys. Rev. E 78, 041124 (2008); 78, 041125 (2008); 79, 031109 (2009)] where the tools of the field theoretical renormalization group were employed to explain and quantitatively describe different types of static and dynamic behavior in the vicinity of multicritical points. Here we give the complete two-loop calculation and analysis of the dynamic renormalization-group flow equations at the multicritical point in anisotropic antiferromagnets in an external magnetic field. We find that the time scales of the order parameters characterizing the parallel and perpendicular ordering with respect to the external field scale in the same way. This holds independent whether the Heisenberg fixed point or the biconical fixed point in statics is the stable one. The nonasymptotic analysis of the dynamic flow equations shows that due to cancellation effects the critical behavior is described, in distances from the critical point accessible to experiments, by the critical behavior qualitatively found in one-loop order. Although one may conclude from the effective dynamic exponents (taking almost their one-loop values) that weak scaling for the order parameter components is valid, the flow of the time-scale ratios is quite different, and they do not reach their asymptotic values.

  16. Development of a (13)C NMR Chemical Shift Prediction Procedure Using B3LYP/cc-pVDZ and Empirically Derived Systematic Error Correction Terms: A Computational Small Molecule Structure Elucidation Method.

    Science.gov (United States)

    Xin, Dongyue; Sader, C Avery; Chaudhary, Om; Jones, Paul-James; Wagner, Klaus; Tautermann, Christofer S; Yang, Zheng; Busacca, Carl A; Saraceno, Reginaldo A; Fandrick, Keith R; Gonnella, Nina C; Horspool, Keith; Hansen, Gordon; Senanayake, Chris H

    2017-05-19

    An accurate and efficient procedure was developed for performing (13)C NMR chemical shift calculations employing density functional theory with the gauge invariant atomic orbitals (DFT-GIAO). Benchmarking analysis was carried out, incorporating several density functionals and basis sets commonly used for prediction of (13)C NMR chemical shifts, from which the B3LYP/cc-pVDZ level of theory was found to provide accurate results at low computational cost. Statistical analyses from a large data set of (13)C NMR chemical shifts in DMSO are presented with TMS as the calculated reference and with empirical scaling parameters obtained from a linear regression analysis. Systematic errors were observed locally for key functional groups and carbon types, and correction factors were determined. The application of this process and associated correction factors enabled assignment of the correct structures of therapeutically relevant compounds in cases where experimental data yielded inconclusive or ambiguous results. Overall, the use of B3LYP/cc-pVDZ with linear scaling and correction terms affords a powerful and efficient tool for structure elucidation.

  17. Long-term energy-balance modeling of interannual snow and ice in Wyoming using the dynamic equilibrium concept

    Science.gov (United States)

    Johnson, Ryan J.

    Many snow models in the field of hydrologic engineering do not incorporate the long-term effects of the interannual snow storage such as glaciers because glacier dynamics have a much longer timescale than river flow and seasonal snowmelt. This study proposes an appropriate treatment for inland glaciers as systems in dynamic equilibrium that remain constant under a static climate condition. This new method considers the vertical movement of snow/ice from high elevation areas to valleys as the equilibrating factor of the glacier system. The vertical movement of snow/ice occurs by means of wind re-distribution, avalanches, and glaciation. This paper introduces and discusses the physically-based modeling of such a dynamic equilibrium snow system for long-term snow simulation at a regional scale. We apply the regional snow model (RegSnow) to a domain containing the entire state of Wyoming and couple the model to the Weather Research and Forecasting (WRF) model to compute the snow surface energy-balance. RegSnow predicted that 82.2% of interannual snow and ice storage in Wyoming may disappear by 2100 using temperature increases projected by CMIP5 GCMs, under the RCP4.5 emission scenario.

  18. ERROR ESTIMATE FOR INFLUENCE OF MODEL REDUCTION OF NONLINEAR DISSIPATIVE AUTONOMOUS DYNAMICAL SYSTEM ON LONG-TERM BEHAVIOURS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jia-zhong; LIU Yan; CHEN Dang-min

    2005-01-01

    From viewpoint of nonlinear dynamics, the model reduction and its influence on the long-term behaviours of a class of nonlinear dissipative autonomous dynamical system with higher dimension are investigated theoretically under some assumptions. The system is analyzed in the state space with an introduction of a distance definition which can be used to describe the distance between the full system and the reduced system, and the solution of the full system is then projected onto the complete space spanned by the eigenvectors of the linear operator of the governing equations. As a result, the influence of mode series tnncation on the long-term behaviours and the error estimate are derived, showing that the error is dependent on the first products of frequencies and damping ratios in the subspace spanned by the eigenvectors with higher modal damping. Furthermore, the fundamental understanding for the topological change of the solution due to the application of different model reduction is interpreted in a mathematically precise way, using the qualitative theory of nonlinear dynamics.

  19. The relation between short-term emotion dynamics and psychological well-being: A meta-analysis.

    Science.gov (United States)

    Houben, Marlies; Van Den Noortgate, Wim; Kuppens, Peter

    2015-07-01

    Not only how good or bad people feel on average, but also how their feelings fluctuate across time is crucial for psychological health. The last 2 decades have witnessed a surge in research linking various patterns of short-term emotional change to adaptive or maladaptive psychological functioning, often with conflicting results. A meta-analysis was performed to identify consistent relationships between patterns of short-term emotion dynamics-including patterns reflecting emotional variability (measured in terms of within-person standard deviation of emotions across time), emotional instability (measured in terms of the magnitude of consecutive emotional changes), and emotional inertia of emotions over time (measured in terms of autocorrelation)-and relatively stable indicators of psychological well-being or psychopathology. We determined how such relationships are moderated by the type of emotional change, type of psychological well-being or psychopathology involved, valence of the emotion, and methodological factors. A total of 793 effect sizes were identified from 79 articles (N = 11,381) and were subjected to a 3-level meta-analysis. The results confirmed that overall, low psychological well-being co-occurs with more variable (overall ρ̂ = -.178), unstable (overall ρ̂ = -.205), but also more inert (overall ρ̂ = -.151) emotions. These effect sizes were stronger when involving negative compared with positive emotions. Moreover, the results provided evidence for consistency across different types of psychological well-being and psychopathology in their relation with these dynamical patterns, although specificity was also observed. The findings demonstrate that psychological flourishing is characterized by specific patterns of emotional fluctuations across time, and provide insight into what constitutes optimal and suboptimal emotional functioning. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  20. The Dynamic Relationship between Growth and Profitability under Long-Term Recession: The Case of Korean Construction Companies

    Directory of Open Access Journals (Sweden)

    Seungkyu Yoo

    2015-12-01

    Full Text Available We conducted an empirical analysis of the dynamic relationship between growth and profitability for small- and medium-sized construction companies that faced long-term economic stagnation in Korea. The period of the analysis spanned 2000 to 2014, and the full period was divided into two halves: before the 2008 global financial crisis and after it. Our empirical model was based on the system generalized method of moments model, and 264 construction companies were used as the study sample. The results of the empirical analysis are as follows. (1 A profitability-driven management strategy limits company growth, thus prolonging the economic downturn; (2 When the macroeconomic environment is relatively stable, high growth in the previous period fosters profitability in the current period. This implies that the phenomenon of dynamic increasing returns is present in the Korean construction industry, and learning through growth enhances productivity and profitability. Consequentially, a strategy oriented towards short-term profitability (popular with small- and medium-sized Korean construction companies makes the corporate management less resilient, causing them to select “de-growth” during the long-term stagnation by decreasing their scale of operations. Accordingly, it is important for companies to maintain the balance between growth and profitability.

  1. Dynamic self-regulating prosthesis (protesi autoregolantesi dinamica): the long-term results in the treatment of primary inguinal hernias.

    Science.gov (United States)

    Valenti, Gabriele; Baldassarre, Emanuele; Testa, Alessandro; Arturi, Alessandro; Torino, Giovanni; Campisi, Costantino; Capuano, Giorgio

    2006-03-01

    The dynamic self-regulating prosthesis (protesi autoregolantesi dinamica, PAD) is a double-layered prosthesi, in use since 1992 in inguinal hernia repair. In 1999, we published the short-term results on 500 patients and herein we report the long-term follow-up. Five hundred eighty-five PAD procedures were performed on 500 adult male, unselected patients. Hernias were unilateral in 415 patients, were bilateral in 85 patients, were direct in 197 patients (33.7%), were indirect in 269 patients (46.0%), and were combined in 119 patients (20.3%). Four hundred sixty-four patients were alive at the follow-up period of minimum 5 years, whereas 36 died (7.2%) of causes unrelated to the hernia. No information was available on 73 patients (14.6%). Therefore, the follow-up was consisted of 391 patients (78.2%) with 469 hernias. The recurrence and testicular atrophy rates were nil. Three patients (0.77%) presented chronic pain and 18 (4.6%) suffered persistent discomfort or paresthesia. A hydrocoele was observed in one patient (0.2%). The long-term data confirm the efficacy of the dynamic self-regulating posthesis hernioplasty. We propose it as a standard of care in all cases of primary inguinal hernia in adult males, retaining it as a definitive and comfortable solution.

  2. THE DYNAMIC FRICTION TERM IN THE SPRING-BLOCK MODELS FOR EARTHQUAKES: A CONSTRAINT FROM SEISMIC MOMENT AND ENERGY CATALOGUE

    Institute of Scientific and Technical Information of China (English)

    吴忠良

    2001-01-01

    In the spring-block models of earthquakes, one of the key factors is the dynamic friction term which determines the complexity of the faulting process. Generally, two kinds of friction, namely velocity-dependent friction and slipdependent friction, are used in the modelling. But until now there has still been a lack of information on which kind of friction term is more suitable for modelling the phenomenology of earthquakes. Based on the numerical studies of Shaw (1998 Bull. Seismol. Soc. Am. 88 1457), we have examined the ratio of the broadband radiated energy and the scalar seismic moment of shallow earthquakes worldwide from 1987 to 1998. The result shows that for earthquakes with strike-slip mechanisms, velocity-dependent friction seems to be predominant, while for thrust and normal events,slip-dependent friction seems predominant. This suggests that in the spring-block models for earthquakes, the type of focal mechanism has to be accounted for, and different types of earthquakes require different dynamic friction terms in the corresponding spring-block model.

  3. Climate change and population dynamics at the tree line: the importance of long-term studies

    Directory of Open Access Journals (Sweden)

    Anfodillo T

    2007-01-01

    Full Text Available Temperature-limited ecosystems are believed to be extremely sensitive to global warming and the upward treeline migration is one of the most relevant phenomenon. Long term monitoring of demographic trends appears essential in order to understand possible effects of higher temperatures on cold ecosystems. Long-term monitoring of natality and mortality of a Pinus sylvestris population in the Swedish Scandes from 1973 to 2005 (Kullman 2007 showed that number of trees increased in the study plots due to higher natality rate, especially in the last decade. This reverses a natural trend of treeline decline and recession occurred in the past.

  4. The dynamical structure of the MEO region: long-term stability, chaos, and transport

    CERN Document Server

    Daquin, Jerome; Deleflie, Florent; Alessi, Elisa Maria; Valsecchi, Giovanni B; Rossi, Alessandro

    2015-01-01

    It has long been suspected that the Global Navigation Satellite Systems exist in a background of complex resonances and chaotic motion; yet, the precise dynamical character of these phenomena remains elusive. Recent studies have shown that the occurrence and nature of the resonances driving these dynamics depend chiefly on the frequencies of nodal and apsidal precession and the rate of regression of the Moon's nodes. Woven throughout the inclination and eccentricity phase space is an exceedingly complicated web-like structure of lunisolar secular resonances, which become particularly dense near the inclinations of the navigation satellite orbits. A clear picture of the physical significance of these resonances is of considerable practical interest for the design of disposal strategies for the four constellations. Here we present analytical and semi-analytical models that accurately reflect the true nature of the resonant interactions, and trace the topological organization of the manifolds on which the chaoti...

  5. Partial dynamical symmetry in quantum Hamiltonians with higher-order terms

    CERN Document Server

    García-Ramos, J E; Van Isacker, P

    2008-01-01

    A generic procedure is proposed to construct many-body quantum Hamiltonians with partial dynamical symmetry. It is based on a tensor decomposition of the Hamiltonian and allows the construction of a hierarchy of interactions that have selected classes of solvable states. The method is illustrated in the SO(6) limit of the interacting boson model of atomic nuclei and applied to the nucleus $^{196}$Pt.

  6. Partial dynamical symmetry in quantum Hamiltonians with higher-order terms.

    Science.gov (United States)

    García-Ramos, J E; Leviatan, A; Van Isacker, P

    2009-03-20

    A generic procedure is proposed to construct many-body quantum Hamiltonians with partial dynamical symmetry. It is based on a tensor decomposition of the Hamiltonian and allows the construction of a hierarchy of interactions that have selected classes of solvable states. The method is illustrated in the SO(6) limit of the interacting boson model of atomic nuclei and applied to the nucleus 196Pt.

  7. Common Terms

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen Common Terms Below is a list of diabetes-related ... a skin condition characterized by darkened skin patches; common in people whose body is not responding correctly ...

  8. Short-Term Dynamics Reveals Seasonality in a Subtropical Heliconius Butterfly

    Directory of Open Access Journals (Sweden)

    Thadeu Sobral-Souza

    2015-01-01

    Full Text Available Although tropical insect populations are generally regarded as constant and stable over time, some of these tropical populations, including butterflies, may fluctuate according to precipitation and temperature variation, specialized feeding patterns, and density-dependent factors. Heliconiini butterfly populations are generally regarded as stable over time because of the presence of host-plants and absence of diapause. However, peaks of abundance occur in subtropical Heliconius populations, and opposite trends concerning stability are found in the literature. Here we further investigate the dynamics of subtropical Heliconius butterflies by assessing a population of the species Heliconius sara apseudes from southeastern Brazil. We estimated individual apparent survival probability and population growth rate while accounting for the imperfect detectability of individuals using mark-recapture models to evaluate the population dynamics. Adult males presented slightly higher weekly survival estimates than females. Contrary to the common pattern described in the literature for Heliconius populations we observed a rapid decline on the adult population by the end of the mating season, possibly leading to local extinction. We discuss the potential drivers for such dynamics.

  9. The Analysis of the Dynamics of the Marketing Services Market in Terms of Strategic Management of Crisis

    Directory of Open Access Journals (Sweden)

    Ivanova Natalya

    2016-12-01

    Full Text Available The aim of the study is to determine the basic modern marketing services according to the dynamics data of the media market of Ukraine. Thus, marketing services are considered as tools that provide crisis man-agement in strategic business development perspective. Scientific and practical significance of the study lies in the results of trend analysis of the dynamics of the media market of Ukraine and its components, the results of which led to the conclusion about the importance of Internet advertising as a modern marketing tool in terms of anti-crisis policy. The study predicted the values of the obtained volumes and market share of Internet advertising in the media market structure in Ukraine for the next period.

  10. [Dynamics of microbial biomass C in a black soil under long-term fertilization and related affecting factors].

    Science.gov (United States)

    Li, Dongpo; Wu, Zhijie; Chen, Lijun; Zhu, Ping; Ren, Jun; Peng, Chang; Liang, Chenghua

    2004-08-01

    The effect of long-term fertilization on the dynamics of microbial biomass C in a typical black soil of Northeastern China was studied in a field trail treated by different fertilizations. The results showed that the amount of soil microbial biomass C under different fertilizations varied significantly with growth stages. It was the highest in farmyard manure (M2 and M4) treatments, with a less seasonal fluctuation, second in NPK treatment, the peak at sowing period, and the lowest in CK, the peak at wax maturity stage. No significant correlation was found between the dynamic changes of soil microbial biomass C and soil biological, physical and chemical properties in all treatments, but the correlation of soil microbial biomass C with the contents of N, P and K in plants and that of crude protein in grain was significantly positive.

  11. Integrated modeling of long-term vegetation and hydrologic dynamics in Rocky Mountain watersheds

    Science.gov (United States)

    Robert Steven Ahl

    2007-01-01

    Changes in forest structure resulting from natural disturbances, or managed treatments, can have negative and long lasting impacts on water resources. To facilitate integrated management of forest and water resources, a System for Long-Term Integrated Management Modeling (SLIMM) was developed. By combining two spatially explicit, continuous time models, vegetation...

  12. Analyzing Crude Oil Spot Price Dynamics versus Long Term Future Prices: A Wavelet Analysis Approach

    Directory of Open Access Journals (Sweden)

    Josué M. Polanco-Martínez

    2016-12-01

    Full Text Available The West Texas Intermediate (WTI spot price shows high volatility and in 2014 and 2015 when quoted prices declined sharply, long-term prices in future markets were less volatile. These prices are different and diverge depending on how they process fundamental and transitory factors. US tight oil production has been a major innovation with significant macroeconomic effects. In this paper we use WTI spot prices and long-term futures prices, the latter calculated as the expected value with a stochastic model calibrated with the futures quotes of each sample day. These long-term prices are the long-term equilibrium value under risk neutral measurement. In order to analyze potential time-scale relationships between spots and future, we perform a wavelet cross-correlation analysis using a novel wavelet graphical tool recently proposed. To check the direction of the causality, we apply non-linear causality tests to raw data and log returns as well as to the wavelet transform of the spot and futures prices. Our results show that in the spot and futures markets for the period 24 February 2006–2 April 2016 there is a bi-directional causality effect for most time scales (from intra-week to biannual. This suggests that spot and futures prices react simultaneously to new information.

  13. Dynamic Management of Digital Rights for Long-term Preservation:the Expert System Approach

    Institute of Scientific and Technical Information of China (English)

    Frédéric MARTIN

    2008-01-01

    This presentation focuses on the complex issue of managing digital rights for long-term preservation.It describes the strategy and the methodology adopted within the SPAR project(French National Library),which rely on a special kind of knowledge-based system.

  14. Short- and long-term tannin induced carbon, nitrogen and phosphorus dynamics in Corsican pine litter

    NARCIS (Netherlands)

    Nierop, K.G.J.; Verstraten, J.M.; Tietema, A.; Westerveld, J.W.; Wartenbergh, P.E.

    2006-01-01

    Pine litter amended with either tannic acid (TA) or condensed tannins (CTs) was studied to assess the effects on C, N and P mineralization in relation to the fate of tannins by incubation experiments during various time intervals. TA induced a rapid short-term effect resulting in high C respiration

  15. Behavior control in the sensorimotor loop with short-term synaptic dynamics induced by self-regulating neurons

    Directory of Open Access Journals (Sweden)

    Hazem eToutounji

    2014-05-01

    Full Text Available The behavior and skills of living systems depend on the distributed control provided by specialized and highly recurrent neural networks. Learning and memory in these systems is mediated by a set of adaptation mechanisms, known collectively as neuronal plasticity. Translating principles of recurrent neural control and plasticity to artificial agents has seen major strides, but is usually hampered by the complex interactions between the agent's body and its environment. One of the important standing issues is for the agent to support multiple stable states of behavior, so that its behavioral repertoire matches the requirements imposed by these interactions. The agent also must have the capacity to switch between these states in time scales that are comparable to those by which sensory stimulation varies. Achieving this requires a mechanism of short-term memory that allows the neurocontroller to keep track of the recent history of its input, which finds its biological counterpart in short-term synaptic plasticity. This issue is approached here by deriving synaptic dynamics in recurrent neural networks. Neurons are introduced as self-regulating units with a rich repertoire of dynamics. They exhibit homeostatic properties for certain parameter domains, which result in a set of stable states and the required short-term memory. They can also operate as oscillators, which allow them to surpass the level of activity imposed by their homeostatic operation conditions. Neural systems endowed with the derived synaptic dynamics can be utilized for the neural behavior control of autonomous mobile agents. The resulting behavior depends also on the underlying network structure, which is either engineered, or developed by evolutionary techniques. The effectiveness of these self-regulating units is demonstrated by controlling locomotion of a hexapod with eighteen degrees of freedom, and obstacle-avoidance of a wheel-driven robot.

  16. Behavior control in the sensorimotor loop with short-term synaptic dynamics induced by self-regulating neurons

    Science.gov (United States)

    Toutounji, Hazem; Pasemann, Frank

    2014-01-01

    The behavior and skills of living systems depend on the distributed control provided by specialized and highly recurrent neural networks. Learning and memory in these systems is mediated by a set of adaptation mechanisms, known collectively as neuronal plasticity. Translating principles of recurrent neural control and plasticity to artificial agents has seen major strides, but is usually hampered by the complex interactions between the agent's body and its environment. One of the important standing issues is for the agent to support multiple stable states of behavior, so that its behavioral repertoire matches the requirements imposed by these interactions. The agent also must have the capacity to switch between these states in time scales that are comparable to those by which sensory stimulation varies. Achieving this requires a mechanism of short-term memory that allows the neurocontroller to keep track of the recent history of its input, which finds its biological counterpart in short-term synaptic plasticity. This issue is approached here by deriving synaptic dynamics in recurrent neural networks. Neurons are introduced as self-regulating units with a rich repertoire of dynamics. They exhibit homeostatic properties for certain parameter domains, which result in a set of stable states and the required short-term memory. They can also operate as oscillators, which allow them to surpass the level of activity imposed by their homeostatic operation conditions. Neural systems endowed with the derived synaptic dynamics can be utilized for the neural behavior control of autonomous mobile agents. The resulting behavior depends also on the underlying network structure, which is either engineered or developed by evolutionary techniques. The effectiveness of these self-regulating units is demonstrated by controlling locomotion of a hexapod with 18 degrees of freedom, and obstacle-avoidance of a wheel-driven robot. PMID:24904403

  17. Unclassified Source Term and Radionuclide Data for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Peter Martian

    2009-05-01

    This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for CAU 97: Yucca Flat/Climax Mine. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. The hydrologic source term (HST) of an underground nuclear test is the portion of the total RST that is released into the groundwater over time following the test. In this report, the HST represents radionuclide release some time after the explosion and does not include the rapidly evolving mechanical, thermal, and chemical processes during the explosion. The CAU 97: Yucca Flat/Climax Mine has many more detonations and a wider variety of settings to consider compared to other CAUs. For instance, the source term analysis and evaluation performed for CAUs 101 and 102: Central and Western Pahute Mesa and CAU 98: Frenchman Flat did not consider vadose zone attenuation because many detonations were located near or below the water table. However, the large number of Yucca Flat/Climax Mine tests and the location of many tests above the water table warrant a more robust analysis of the unsaturated zone.

  18. A fast network solution by the decoupled procedure during short-term dynamic processes in power systems

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, D.P.; Stefanovic, M.D. (Nikola Tesla Inst., Belgrade (YU). Power System Dept.)

    1990-01-01

    A simple, fast and reliable decoupled procedure for solving the network problems during short-term dynamic processes in power systems is presented. It is based on the Newton-Raphson method applied to the power balance equations, which include the effects of generator saliency and non-impedance loads, with further modifications resulting from the physical properties of the phenomena under study. The good convergence characteristics of the developed procedure are demonstrated, and a comparison is made with the traditional method based on the current equation and the triangularized admittance matrix, using the example of stability analysis of the Yugoslav power grid. (author).

  19. An exact representation of the fermion dynamics in terms of Poisson processes and its connection with Monte Carlo algorithms

    Science.gov (United States)

    Beccaria, M.; Presilla, C.; DeAngelis, G. F.; Jona-Lasinio, G.

    1999-11-01

    We present a simple derivation of a Feynman-Kac type formula to study fermionic systems. In this approach the real time or the imaginary time dynamics is expressed in terms of the evolution of a collection of Poisson processes. This formula leads to a family of algorithms parametrized by the values of the jump rates of the Poisson processes. From these an optimal algorithm can be chosen which coincides with the Green Function Monte Carlo method in the limit when the latter becomes exact.

  20. Towards self-correcting quantum memories

    Science.gov (United States)

    Michnicki, Kamil

    This thesis presents a model of self-correcting quantum memories where quantum states are encoded using topological stabilizer codes and error correction is done using local measurements and local dynamics. Quantum noise poses a practical barrier to developing quantum memories. This thesis explores two types of models for suppressing noise. One model suppresses thermalizing noise energetically by engineering a Hamiltonian with a high energy barrier between code states. Thermalizing dynamics are modeled phenomenologically as a Markovian quantum master equation with only local generators. The second model suppresses stochastic noise with a cellular automaton that performs error correction using syndrome measurements and a local update rule. Several ways of visualizing and thinking about stabilizer codes are presented in order to design ones that have a high energy barrier: the non-local Ising model, the quasi-particle graph and the theory of welded stabilizer codes. I develop the theory of welded stabilizer codes and use it to construct a code with the highest known energy barrier in 3-d for spin Hamiltonians: the welded solid code. Although the welded solid code is not fully self correcting, it has some self correcting properties. It has an increased memory lifetime for an increased system size up to a temperature dependent maximum. One strategy for increasing the energy barrier is by mediating an interaction with an external system. I prove a no-go theorem for a class of Hamiltonians where the interaction terms are local, of bounded strength and commute with the stabilizer group. Under these conditions the energy barrier can only be increased by a multiplicative constant. I develop cellular automaton to do error correction on a state encoded using the toric code. The numerical evidence indicates that while there is no threshold, the model can extend the memory lifetime significantly. While of less theoretical importance, this could be practical for real

  1. Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles

    Science.gov (United States)

    Hobbie, Erik A.; Chen, Janet; Hanson, Paul J.; Iversen, Colleen M.; McFarlane, Karis J.; Thorp, Nathan R.; Hofmockel, Kirsten S.

    2017-05-01

    Peatlands encode information about past vegetation dynamics, climate, and microbial processes. Here, we used δ15N and δ13C patterns from 16 peat profiles to deduce how the biogeochemistry of the Marcell S1 forested bog in northern Minnesota responded to environmental and vegetation change over the past ˜ 10 000 years. In multiple regression analyses, δ15N and δ13C correlated strongly with depth, plot location, C / N, %N, and each other. Correlations with %N, %C, C / N, and the other isotope accounted for 80 % of variance for δ15N and 38 % of variance for δ13C, reflecting N and C losses. In contrast, correlations with depth and topography (hummock or hollow) reflected peatland successional history and climate. Higher δ15N in plots closer to uplands may reflect upland-derived DON inputs and accompanying shifts in N dynamics in the lagg drainage area surrounding the bog. The Suess effect (declining δ13CO2 since the Industrial Revolution) lowered δ13C in recent surficial samples. High δ15N from -35 to -55 cm probably indicated the depth of ectomycorrhizal activity after tree colonization of the peatland over the last 400 years, as confirmed by the occasional presence of wood down to -35 cm depth. High δ13C at ˜ 4000 years BP (-65 to -105 cm) could reflect a transition at that time to slower rates of peat accumulation, when 13C discrimination during peat decomposition may increase in importance. Low δ13C and high δ15N at -213 and -225 cm ( ˜ 8500 years BP) corresponded to a warm period during a sedge-dominated rich fen stage. The above processes appear to be the primary drivers of the observed isotopic patterns, whereas there was no clear evidence for methane dynamics influencing δ13C patterns.

  2. Prediction of Settlements of Soft Clay Subjected to Long-Term Dynamic Load

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    -Presented is the numerical analysis of settlements of soft soil by a 2-D dynamic effective stress FEM method. The model based on the results of cyclic triaxial tests on the reconstituted soft Ariake clay is used to predict the wave induced excess pore water pressure and residual strain of soft clay. The settlements of two types of breakwaters on the soft clay under ocean wave load, a low embankment subjected to traffic load and the tunnel surrounded by soft clay in Shanghai subjected to locomotive load are calculated as examples.

  3. Short-term Prediction and Detection of Dynamic Atmospheric Effects by Microwave Radiometer

    Directory of Open Access Journals (Sweden)

    P. Dvorak

    2012-12-01

    Full Text Available Specific utilization of a microwave radiometer for online monitoring, detection and, especially, prediction of particular dynamic atmospheric effects such as precipitation and cloudiness is proposed in the paper. The ground-based microwave radiometer and meteorological stations were incorporated into the measurement campaign in order to observe actual brightness temperature changes. The characteristics of atmospheric parameters recorded over a period of 14 months were evaluated and new applications for rain forecasting and cloud detection, based on signal variance, were proposed and validated.

  4. Soil heavy metal dynamics and risk assessment under long-term land use and cultivation conversion.

    Science.gov (United States)

    Wang, Xuelei; Xu, Yiming

    2015-01-01

    Long-term agricultural development and cultivation conversions affect soil heavy metal balance and the regional environmental safety. In this study, heavy metal parameters were used to identify changes in soil properties in response to land use and cultivation conversions. The integrated soil quality index, which involves seven heavy metal indices, was proposed to assess the environmental risk of long-term human activities in Northeast China. We used the remote sensing and geographical data for the four-term land use distribution from 1979 to 2009 to identify the spatial patterns of regional land use conversions. Then, 41 samples from the top 20 cm of the soil at sites corresponding to these seven types of conversions were collected (permanent dry land, dry land converted from wetland, dry land converted from forest, permanent wetland, permanent forest, paddy land converted from dry land, and paddy land converted from wetland). Based on the local soil properties and tillage practices, the following seven heavy metal parameters were employed: Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn). The conversion of farmland from wetland resulted in an increase in the concentration of Pb and Cr in the soil. In contrast, the concentrations of Zn, Cu, Ni, and Cd decreased when wetland was converted into farmland because the tillage practices washed these heavy metals away. During the conversion of dry land and paddy land to wetland, the levels of Pb increased by approximately 28.6% and 24.7%, respectively. Under the same conditions, the concentration of As increased by 32.5% and 14.1%, respectively. The integrated index also demonstrated that the farmlands were not contaminated by the heavy metals during long-term agricultural development.

  5. A dynamic nonstationary spatio-temporal model for short term prediction of precipitation

    OpenAIRE

    Sigrist, Fabio; Künsch, Hans R.; Stahel, Werner A.

    2011-01-01

    Precipitation is a complex physical process that varies in space and time. Predictions and interpolations at unobserved times and/or locations help to solve important problems in many areas. In this paper, we present a hierarchical Bayesian model for spatio-temporal data and apply it to obtain short term predictions of rainfall. The model incorporates physical knowledge about the underlying processes that determine rainfall, such as advection, diffusion and convection. It...

  6. Unclassified Sources Term and Radionuclide Data for Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    Peter Martian

    2009-08-01

    This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for CAU 97: Yucca Flat/Climax Mine. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. The hydrologic source term (HST) of an underground nuclear test is the portion of the total RST that is released into the groundwater over time following the test. In this report, the HST represents radionuclide release some time after the explosion and does not include the rapidly evolving mechanical, thermal, and chemical processes during the explosion. The CAU 97: Yucca Flat/Climax Mine has many more detonations and a wider variety of settings to consider compared to other CAUs. For instance, the source term analysis and evaluation performed for CAUs 101 and 102: Central and Western Pahute Mesa and CAU 98: Frenchman Flat did not consider vadose zone attenuation because many detonations were located near or below the water table. However, the large number of Yucca Flat/Climax Mine tests and the location of many tests above the water table warrant a more robust analysis of the unsaturated zone. The purpose of this report is to develop and document conceptual models of the Yucca Flat/Climax Mine HST for use in implementing source terms for the Yucca Flat/Climax Mine models. This document presents future plans to incorporate the radionuclide attenuation mechanisms due to unsaturated/multiphase flow and transport within the Yucca Flat CAU scale modeling. The important processes that influence radionuclide migration for the unsaturated and saturated tests in alluvial, volcanic, and carbonate settings are identified. Many different flow and transport models developed by Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), including original

  7. Simulations of long-term community dynamics in coral reefs--how perturbations shape trajectories.

    Directory of Open Access Journals (Sweden)

    Andreas Kubicek

    Full Text Available Tropical coral reefs feature extraordinary biodiversity and high productivity rates in oligotrophic waters. Due to increasing frequencies of perturbations--anthropogenic and natural--many reefs are under threat. Such perturbations often have devastating effects on these unique ecosystems and especially if they occur simultaneously and amplify each other's impact, they might trigger a phase shift and create irreversible conditions.We developed a generic, spatially explicit, individual-based model in which competition drives the dynamics of a virtual benthic reef community--comprised of scleractinian corals and algae--under different environmental settings. Higher system properties, like population dynamics or community composition arise through self-organization as emergent properties. The model was parameterized for a typical coral reef site at Zanzibar, Tanzania and features coral bleaching and physical disturbance regimes as major sources of perturbations. Our results show that various types and modes (intensities and frequencies of perturbations create diverse outcomes and that the switch from high diversity to single species dominance can be evoked by small changes in a key parameter. Here we extend the understanding of coral reef resilience and the identification of key processes, drivers and respective thresholds, responsible for changes in local situations. One future goal is to provide a tool which may aid decision making processes in management of coral reefs.

  8. Understanding the dynamics of rings in the melt in terms of the annealed tree model.

    Science.gov (United States)

    Smrek, Jan; Grosberg, Alexander Y

    2015-02-18

    The dynamical properties of a long polymer ring in a melt of unknotted and unconcatenated rings are calculated. We re-examine and generalize the well known model of a ring confined to a lattice of topological obstacles in light of the recently developed Flory theory of untangled rings which maps every ring on an annealed branched polymer and establishes that the backbone associated with each ring follows self-avoiding rather than Gaussian random walk statistics. We find the scaling of the ring relaxation time and diffusion coefficient with ring length, as well as the time dependence of stress relaxation modulus, zero shear viscosity and the mean square averaged displacements of both individual monomers and the ring's mass centre. Our results agree within error bars with all available experimental and simulation data of the ring melt, although the quality of the data so far is insufficient to make a definitive judgement for or against the annealed tree theory. At the end we review briefly the relation between our findings and experimental data on chromatin dynamics.

  9. Munc18-1 is a dynamically regulated PKC target during short-term enhancement of transmitter release.

    Science.gov (United States)

    Genc, Ozgür; Kochubey, Olexiy; Toonen, Ruud F; Verhage, Matthijs; Schneggenburger, Ralf

    2014-02-11

    Transmitter release at synapses is regulated by preceding neuronal activity, which can give rise to short-term enhancement of release like post-tetanic potentiation (PTP). Diacylglycerol (DAG) and Protein-kinase C (PKC) signaling in the nerve terminal have been widely implicated in the short-term modulation of transmitter release, but the target protein of PKC phosphorylation during short-term enhancement has remained unknown. Here, we use a gene-replacement strategy at the calyx of Held, a large CNS model synapse that expresses robust PTP, to study the molecular mechanisms of PTP. We find that two PKC phosphorylation sites of Munc18-1 are critically important for PTP, which identifies the presynaptic target protein for the action of PKC during PTP. Pharmacological experiments show that a phosphatase normally limits the duration of PTP, and that PTP is initiated by the action of a 'conventional' PKC isoform. Thus, a dynamic PKC phosphorylation/de-phosphorylation cycle of Munc18-1 drives short-term enhancement of transmitter release during PTP. DOI: http://dx.doi.org/10.7554/eLife.01715.001.

  10. Bioengineered coagulation factor VIII enables long-term correction of murine hemophilia A following liver-directed adeno-associated viral vector delivery

    Directory of Open Access Journals (Sweden)

    Harrison C Brown

    2014-01-01

    Full Text Available Clinical data support the feasibility and safety of adeno-associated viral (AAV vectors in gene therapy applications. Despite several clinical trials of AAV-based gene transfer for hemophilia B, a unique set of obstacles impede the development of a similar approach for hemophilia A. These include (i the size of the factor VIII (fVIII transgene, (ii humoral immune responses to fVIII, (iii inefficient biosynthesis of human fVIII, and (iv AAV vector immunity. Through bioengineering approaches, a novel fVIII molecule, designated ET3, was developed and shown to improve biosynthetic efficiency 10- to 100-fold. In this study, the utility of ET3 was assessed in the context of liver-directed, AAV-mediated gene transfer into hemophilia A mice. Due to the large size of the expression cassette, AAV-ET3 genomes packaged into viral particles as partial genome fragments. Despite this potential limitation, a single peripheral vein administration of AAV-ET3 into immune-competent hemophilia A mice resulted in correction of the fVIII deficiency at lower vector doses than previously reported for similarly oversized AAV-fVIII vectors. Therefore, ET3 appears to improve vector potency and mitigate at least one of the critical barriers to AAV-based clinical gene therapy for hemophilia A.

  11. Bianchi I model in terms of non-standard LQC: Classical dynamics

    CERN Document Server

    Dzierzak, Piotr

    2009-01-01

    The cosmological singularities of the Bianchi I universe are analyzed in the setting of loop geometry underlying the loop quantum cosmology. We solve the Hamiltonian constraint of the theory and find the Lie algebra of elementary observables. Physical compound observables are defined in terms of elementary ones. Modification of classical theory by holonomy around a loop removes the singularities. However, our model has a free parameter that cannot be determined within our method. Testing the model by the data of observational cosmology may be possible after quantization of our modified classical theory.

  12. Long-Term Sediment Dynamics in a Tidal Salt Marsh, North Inlet, South Carolina

    Science.gov (United States)

    Murphy, S.; Voulgaris, G.

    2001-05-01

    The salt marshes along the southeastern U.S. coast are in a delicate balance between rates of sediment accretion and relative sea level rise. Short-term sediment flux studies in the region indicate a net export of suspended sediment out of salt marsh systems despite the necessity for these marshes to import sediment in order to keep pace with relative sea level rise. Long-term suspended sediment concentration data collected daily through the Long-Term Ecological Research Program (LTER) are utilized in this study. The objective of this study is to identify the relative importance of different processes including tidal range, rainfall, winds, water temperature and river discharge in effecting suspended sediment concentrations in salt marsh channels. The study area is a small {\\Spartina}- and {\\Juncus}-dominated salt marsh located at North Inlet, South Carolina. Suspended sediment concentrations were collected daily at 3 sites in the marsh basin at approximately 1000 hrs EST for a period of 10 to 15 years. The determination of how suspended sediment concentrations vary with respect to the tidal cycle required identification of the phase within the cycle that the sample was collected. This was achieved predicting tidal phases using sea surface elevation data. Suspended sediment concentrations collected during periods of different rainfall, tidal ranges, wind conditions, water temperatures and freshwater discharge were used to develop "representative" tidal cycles for each of the aforementioned forcings. Mean suspended sediment concentrations were found to be highest during the ebb tide while the lowest concentrations were found following high and low slack water. These concentrations vary spatially throughout the marsh with the highest concentrations located at the most landward site and lowest at the site nearest the inlet. A seasonal bias of suspended sediment concentrations was observed with highest concentrations in the summer months. Import of sediment in the

  13. Recent seismic activity at Cephalonia island (Greece): a study through candidate electromagnetic precursors in terms of nonlinear dynamics

    Science.gov (United States)

    Potirakis, S. M.; Contoyiannis, Y.; Melis, N. S.; Kopanas, J.; Antonopoulos, G.; Balasis, G.; Kontoes, C.; Nomicos, C.; Eftaxias, K.

    2015-12-01

    The preparation process of two recent earthquakes (EQs) occurred in Cephalonia (Kefalonia) island, Greece, (38.22° N, 20.53° E), 26 January 2014, Mw =6.0, depth =21 km, and (38.25° N, 20.39° E), 3 February 2014, Mw =5.9, depth =10 km, respectively, is studied in terms of the critical dynamics revealed in observables of the involved non-linear processes. Specifically, we show, by means of the method of critical fluctuations (MCF), that signatures of critical, as well as tricritical, dynamics were embedded in the fracture-induced electromagnetic emissions (EME) recorded by two stations in locations near the epicenters of these two EQs. It is worth noting that both, the MHz EME recorded by the telemetric stations on the island of Cephalonia and the neighboring island of Zante (Zakynthos), reached simultaneously critical condition a few days before the occurrence of each earthquake. The critical characteristics embedded in the EME signals were further verified using the natural time (NT) method. Moreover, we show, in terms of the NT method, that the foreshock seismic activity also presented critical characteristics before each one of these events. Importantly, the revealed critical process seems to be focused on the area corresponding to the west Cephalonia zone, following the seismotectonic and hazard zoning of the Ionian Islands area near Cephalonia.

  14. Recent seismic activity at Cephalonia (Greece): a study through candidate electromagnetic precursors in terms of non-linear dynamics

    Science.gov (United States)

    Potirakis, Stelios M.; Contoyiannis, Yiannis; Melis, Nikolaos S.; Kopanas, John; Antonopoulos, George; Balasis, Georgios; Kontoes, Charalampos; Nomicos, Constantinos; Eftaxias, Konstantinos

    2016-08-01

    The preparation process of two recent earthquakes (EQs) that occurred in Cephalonia (Kefalonia), Greece, ((38.22° N, 20.53° E), 26 January 2014, Mw = 6.0, depth ˜ 20 km) and ((38.25° N, 20.39° E), 3 February 2014, Mw = 5.9, depth ˜ 10 km), respectively, is studied in terms of the critical dynamics revealed in observables of the involved non-linear processes. Specifically, we show, by means of the method of critical fluctuations (MCF), that signatures of critical, as well as tricritical, dynamics were embedded in the fracture-induced electromagnetic emissions (EMEs) recorded by two stations in locations near the epicentres of these two EQs. It is worth noting that both the MHz EMEs recorded by the telemetric stations on the island of Cephalonia and the neighbouring island of Zante (Zakynthos) reached a simultaneously critical condition a few days before the occurrence of each earthquake. The critical characteristics embedded in the EME signals were further verified using the natural time (NT) method. Moreover, we show, in terms of the NT method, that the foreshock seismic activity also presented critical characteristics before each event. Importantly, the revealed critical process seems to be focused on the area corresponding to the western Cephalonia zone, following the seismotectonic and hazard zoning of the Ionian Islands area near Cephalonia.

  15. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    Science.gov (United States)

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu.

  16. Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu: Responses to nutrient enrichment and meteorological factors

    Science.gov (United States)

    Shi, Kun; Zhang, Yunlin; Zhou, Yongqiang; Liu, Xiaohan; Zhu, Guangwei; Qin, Boqiang; Gao, Guang

    2017-01-01

    We developed and validated an empirical model for estimating chlorophyll a concentrations (Chla) in Lake Taihu to generate a long-term Chla and algal bloom area time series from MODIS-Aqua observations for 2003 to 2013. Then, based on the long-term time series data, we quantified the responses of cyanobacterial dynamics to nutrient enrichment and climatic conditions. Chla showed substantial spatial and temporal variability. In addition, the annual mean cyanobacterial surface bloom area exhibited an increasing trend across the entire lake from 2003 to 2013, with the exception of 2006 and 2007. High air temperature and phosphorus levels in the spring can prompt cyanobacterial growth, and low wind speeds and low atmospheric pressure levels favor cyanobacterial surface bloom formation. The sensitivity of cyanobacterial dynamics to climatic conditions was found to vary by region. Our results indicate that temperature is the most important factor controlling Chla inter-annual variability followed by phosphorus and that air pressure is the most important factor controlling cyanobacterial surface bloom formation followed by wind speeds in Lake Taihu. PMID:28074871

  17. Dynamics of ecological and biological characteristics of soddy-podzolic soils under long-term oil pollution

    Science.gov (United States)

    Petrov, A. M.; Versioning, A. A.; Karimullin, L. K.; Akaikin, D. V.; Tarasov, O. Yu.

    2016-07-01

    The dynamics of respiratory and enzyme activities and toxicological properties of loamy-sandy and loamy soddy-podzolic soils (Retisols) under the long-term influence of oil pollution were studied. The concentrations of the pollutant, at which the activity (the ability of self-purification) of the indigenous soil microflora is preserved, were determined. The dynamics of the decrease of oil product content and the time of elimination of the toxic effects on higher plants at the initial pollutant contents were revealed. The parameters of the respiratory and enzyme activities in the course of the 365-day experiment showed that the microbial community of the loamy-sandy soil was more sensitive to oil pollution. The phytotoxic characteristics of the oil-containing loamy-sandy and loamy soils did not correlate with their respiratory and enzyme activities. This fact testifies to some differences in the mechanisms of their influence on living organisms with different organizational levels and to the necessity of taking into account a complex of parameters when assessing the state of the soils under the long-term effects of oil and its products.

  18. Recent seismic activity at Cephalonia island (Greece: a study through candidate electromagnetic precursors in terms of nonlinear dynamics

    Directory of Open Access Journals (Sweden)

    S. M. Potirakis

    2015-12-01

    Full Text Available The preparation process of two recent earthquakes (EQs occurred in Cephalonia (Kefalonia island, Greece, (38.22° N, 20.53° E, 26 January 2014, Mw =6.0, depth =21 km, and (38.25° N, 20.39° E, 3 February 2014, Mw =5.9, depth =10 km, respectively, is studied in terms of the critical dynamics revealed in observables of the involved non-linear processes. Specifically, we show, by means of the method of critical fluctuations (MCF, that signatures of critical, as well as tricritical, dynamics were embedded in the fracture-induced electromagnetic emissions (EME recorded by two stations in locations near the epicenters of these two EQs. It is worth noting that both, the MHz EME recorded by the telemetric stations on the island of Cephalonia and the neighboring island of Zante (Zakynthos, reached simultaneously critical condition a few days before the occurrence of each earthquake. The critical characteristics embedded in the EME signals were further verified using the natural time (NT method. Moreover, we show, in terms of the NT method, that the foreshock seismic activity also presented critical characteristics before each one of these events. Importantly, the revealed critical process seems to be focused on the area corresponding to the west Cephalonia zone, following the seismotectonic and hazard zoning of the Ionian Islands area near Cephalonia.

  19. GPS station short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2016-07-01

    Full Text Available Continuous observation data from 24 GPS stations are selected in the area (33.0°N–41.0°N, 95.0°E–105.0°E for this study (the period is from Jan. 1, 2015 to Jan. 20, 2016. Three components, NS, EW and UD, of the daily solutions are filtered by the Hilbert–Huang transform (HHT with frequency band of 5.787 × 10−7–7.716 × 10−8 Hz (20–150 days in period. And short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake are studied by using the temporal dependencies and cross spectrum analysis. The results show that before the earthquake the horizontal undulatory motions are higher than the average level in the series data which indicate the disturbance feature of regional stress before the earthquake. Three GPS stations on Qinghai-Tibet Plateau with their setting perpendicular to the seismogenic fault have consistent movement. The increase of amplitude of the horizontal micro motion observed before the quake is conducive to the earthquake occurrence. However, we could not be sure if the undulatory motion triggered the earthquake. It is quite necessary to build more GPS continuous observation stations and optimize the monitoring network so as to improve the understanding of the short-term dynamic crustal variation before earthquake.

  20. Long-term agricultural non-point source pollution loading dynamics and correlation with outlet sediment geochemistry

    Science.gov (United States)

    Ouyang, Wei; Jiao, Wei; Li, Xiaoming; Giubilato, Elisa; Critto, Andrea

    2016-09-01

    Some agricultural non-point source (NPS) pollutants accumulate in sediments in the outlet sections of watersheds. It is crucial to evaluate the historical interactions between sediment properties and watershed NPS loading. Therefore, a sediment core from the outlet of an agricultural watershed was collected. The core age was dated using the 210Pb method, and sedimentation rates were determined using the constant rate of supply (CRS) model. The total nitrogen (TN), total phosphorus (TP), Cd, Pb, Cu, Ni and Cr accumulations in the sediment generally showed fluctuating increases, with the highest sedimentation fluxes all occurring in approximately 1998. The measurement of specific mass sedimentation rates reflected a record of watershed soil erosion dynamics. Using SWAT (Soil and Water Assessment Tool) to simulate long-term watershed agricultural NPS pollution loadings, the historical interactions between sediment properties and NPS loadings were further evaluated. The N leaching process weakened these interactions, but the historical accumulations of TP and heavy metals in sediments generally correlated well with watershed NPS TP loading. The regression analysis suggested that Pb and Cr were the most suitable indexes for assessing long-term NPS TN and TP pollution, respectively. Assessing the NPS loading dynamics using the vertical characteristics of sediment geochemistry is a new method.

  1. Feedbacks between subglacial dynamics and long-term glacial landscape evolution

    DEFF Research Database (Denmark)

    Brædstrup, Christian; Egholm, D.L.; Ugelvig, Sofie Vej;

    , but also on the details of the bed topography and the regional variations in ice flow velocity. As glaciers erode their beds and modify the morphology of glaciated valleys, the subglacial dynamics therefore change with important implications for the sliding patterns and the continued erosion rates. We...... landforms has so far mostly been explored using phenomenological models that simply link the subglacial erosion rate to sliding or ice discharge. In order to improve our understanding of the causal links between the glacial landforms and the physics of the subglacial environment, we have performed...... focus this presentation on feedbacks between the evolving bed topography and the subglacial erosion patterns. We have performed our experiments with different sliding and erosion laws, including highly non-linear rules representing coulomb-type slip at the bed (Schoof, 2010) and a quarrying model...

  2. THE BASIC LAWS AND FEATURES OF CYTOKINE DYNAMICS IN PROCESS AND EARLY TERMS AFTER CARDIOPULMONARY BYPASS

    Directory of Open Access Journals (Sweden)

    S. I. Suskov

    2011-01-01

    Full Text Available The basic variants of cytokines reactions defining type of organ dysfunctions are revealed in the course of car- diopulmonary bypass and in the early postoperative period. Their character and expression, depends on gravity preoperative an immunodeficiency and initial degree of heart insufficiency. Diphasic dynamics of development of system inflammatory reaction is confirmed after cardiopulmonary bypass: increase of levels proinflammatory cytokines is in the first phase and anti-inflammatory cytokines with development immunodepression and cellular anergy in is the second phase. Also, key role IL-1Ra is revealed in restraint of hyperactivation of system inflam- matory reaction. Blood whey levels IL-6, IL-8, G-CSF, TNF-α and IL-1Ra should be defined to cardiopulmonary bypass, in 10–12 hours, 24 hours and 3 days after cardiopulmonary bypass and may be used as prognostic criteria of development of postoperative complications. 

  3. Carbon, nitrogen and heavy metal dynamics in long-term wastewater irrigated Mexican soils.

    Science.gov (United States)

    Herre, A; Siebe, C; Kaupenjohann, M

    2000-01-01

    In column experiments of Mexican wastewater irrigated soils the effects of changing water quality (untreated = UT, primary = PT and tertiary treated = TT wastewater) on carbon, nitrogen and heavy metal dynamics were investigated. In the column effluents the nitrate concentrations varied between 141-683 mg l-1. The total amount of leached TOC decreased in the order UT > PT > TT. Outflow concentrations of Pb ranged from 31.6-166.5 micrograms l-1 and of Cu from 31.2-146.8 micrograms l-1. Irrigation water quality influenced the Pb but not the Cu efflux. Cu seemed to be co-transported with TOC by preferential flow whereas there was no correlation of Pb and TOC concentrations in the effluents. The possibility of Pb transport through preferential flow paths is discussed.

  4. Short-term poverty dynamics of rural households: Evidence from Central Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Stefan Schwarze

    2011-12-01

    Full Text Available The understanding of poverty dynamics is crucial for the design of appropriate poverty reduction strategies. Taking the case of Central Sulawesi, we investigate the determinants of both chronic and transitory poverty using data from 264 randomly selected households interviewed in 2005 and 2007. Regarding the US 1$/day poverty line, the headcount index declined from 19.3% in 2005 to 18.2% in 2007. However, we observed an increasing number of people living on less than US 2$/day expressed in purchasing power parity (PPP. The results of the estimated multinomial logit model applied in this study indicate that a lack of non-agricultural employment opportunities and low endowment of social capital are major determinants of chronic as well as transitory poverty in this province of Indonesia. These results are used to draw policy conclusions with respect to the alleviation of transitory and chronic poverty in Central Sulawesi.

  5. Quantifying and Modelling Long Term Sediment Dynamics in Catchments in Western Europe

    Science.gov (United States)

    Notebaert, B.; De Brue, H.; Verstraeten, G.; Broothaerts, N.

    2015-12-01

    Quantification of sediment dynamics allows to get insight in driving forces and internal dynamics of the sediment cascade system. A useful tool to achieve this is the sediment budget approach, which encompasses the quantification of different sinks and sources. A Holocene time-differentiated sediment budget has been constructed for the Belgian Dijle River catchment (720 km²), based on a large set of field data. The results show how soil erosion is driven by land use changes over longer timescales. Sediment redistribution and the relative importance of the different sinks also vary over time, mainly as a result of changing land use and related landscape connectivity. However, the coarse temporal resolution typically associated with Holocene studies complicates the understanding of sub-millennial scale processes. In a second step, the field-based sediment budget was combined with a modeling approach using Watem/Sedem, a spatially distributed model that simulates soil erosion and colluvial deposition. After validation of the model calibration against the sediment budget, the model was used in a sensitivity analysis. Results confirm the overwhelming influence of human land use on both soil erosion and landscape connectivity, whereas the climatic impact is comparatively small. In addition to catchment-wide simulations, the model also served to test the relative importance of lynchets and dry valleys in different environments. Finally, the geomorphic model was used to simulate past land use, taking into account equifinality. For this purpose, a large series of hypothetical time-independent land use maps of the Dijle catchment were modeled based on a multi-objective allocation algorithm, and applied in Watem/Sedem. Modeled soil erosion and sediment deposition outcomes for each scenario were subsequently compared with the field-based record, taking into account uncertainties. As such, the model allows to evaluate and select realistic land use scenarios for the Holocene.

  6. An Examination of Long-Term Environmental-Social Dynamics in the Balkans

    Science.gov (United States)

    Kulkarni, C.; Boger, R. A.

    2015-12-01

    This study examines the interactions of environmental and social dynamics in Central Balkans over the past millennium, a period that experienced three major climatic phases (Medieval Climate Anomaly, Little Ice Age, and the warm 20th century). Meanwhile, the same period witnessed a complex human history with the emergence-rise-decline of the Ottoman Empire and subsequent socio-political events (e.g. wars, famines, migrations). Environmental datasets for the analysis include biological proxies (pollen, spores, and charcoal), geochemical signals through X-ray fluorescence (XRF), and a detailed chronology based on AMS 14C dating of two western and central Serbian lakes while social datasets include historic population data, land use, settlement patterns, and critical historic events derived from a review of the literature and local archives. Among the environmental datasets, indigenous tree and herbaceous pollen from these Central Balkans records demonstrate fluctuations in woodland-grassland dynamics whereas potassium and titanium counts obtained through XRF act as a proxy for surface erosion and clastic input into the lakes. Microscopic charcoal, cereal pollen and subordinate anthropogenic pollen (e.g. cultivated fruits and vegetables) are used to distinguish strong human impact over the landscape. These key anthropogenic indicators create a more thorough social component of the analysis in association with the social datasets. After reconstructing the individual time series for each environmental and social dataset, the two Central Balkan records are correlated in order to identify the environmental and social homogeneity and heterogeneity patterns occurring at shorter and longer timescales during the period. Results provide insights on how a region responds to social and environmental stressors and our approach demonstrates ways to integrate natural and social science system research.

  7. Gravitational Correction to Vacuum Polarization

    CERN Document Server

    Jentschura, U D

    2015-01-01

    We consider the gravitational correction to (electronic) vacuum polarization in the presence of a gravitational background field. The Dirac propagators for the virtual fermions are modified to include the leading gravitational correction (potential term) which corresponds to a coordinate-dependent fermion mass. The mass term is assumed to be uniform over a length scale commensurate with the virtual electron-positron pair. The on-mass shell renormalization condition ensures that the gravitational correction vanishes on the mass shell of the photon, i.e., the speed of light is unaffected by the quantum field theoretical loop correction, in full agreement with the equivalence principle. Nontrivial corrections are obtained for off-shell, virtual photons. We compare our findings to other works on generalized Lorentz transformations and combined quantum-electrodynamic gravitational corrections to the speed of light which have recently appeared in the literature.

  8. 7 CFR 800.165 - Corrected certificates.

    Science.gov (United States)

    2010-01-01

    ... this process shall be corrected according to this section. (b) Who may correct. Only official personnel.... According to this section and the instructions, corrected certificates shall show (i) the termsCorrected... that has been superseded by another certificate or on the basis of a subsequent analysis for...

  9. Long-term trends in the middle atmosphere dynamics at northern middle latitudes – one regime or two different regimes?

    Directory of Open Access Journals (Sweden)

    J. Lastovicka

    2010-02-01

    Full Text Available Due to increasing atmospheric concentration of greenhouse gases and changing stratospheric ozone concentration, both of anthropogenic origin, various quantities in the middle atmosphere reveal long-term changes and trends. Lastovicka and Krizan (2006 indicated possibility of change of trends in the dynamics in the northern midlatitude middle atmosphere as a whole in the 1990s. To search for such change of trends we use data on winds in the mesopause region, on total columnar ozone, on ozone laminae, on winds in the middle and lower stratosphere, and on peak electron density in the E region of the ionosphere. One group of quantities, the mesopause region wind-like trends, changes their trends around 1990, the other one, the total ozone-like trends, in the mid-1990s. Altogether they create a skeleton of scenario of the change of the middle atmosphere dynamics trends in the 1990s. Drivers of these changes appear to be different for the first group and for the second group. Tropospheric processes seem to play a role in the changes of trends in middle atmospheric dynamics.

  10. Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of bank voles (Myodes glareolus) in NE Poland.

    Science.gov (United States)

    Grzybek, Maciej; Bajer, Anna; Bednarska, Małgorzata; Al-Sarraf, Mohammed; Behnke-Borowczyk, Jolanta; Harris, Philip D; Price, Stephen J; Brown, Gabrielle S; Osborne, Sarah-Jane; Siński, Edward; Behnke, Jerzy M

    2015-12-01

    Parasites are considered to be an important selective force in host evolution but ecological studies of host-parasite systems are usually short-term providing only snap-shots of what may be dynamic systems. We have conducted four surveys of helminths of bank voles at three ecologically similar woodland sites in NE Poland, spaced over a period of 11 years, to assess the relative importance of temporal and spatial effects on helminth infracommunities. Some measures of infracommunity structure maintained relative stability: the rank order of prevalence and abundance of Heligmosomum mixtum, Heligmosomoides glareoli and Mastophorus muris changed little between the four surveys. Other measures changed markedly: dynamic changes were evident in Syphacia petrusewiczi which declined to local extinction, while the capillariid Aonchotheca annulosa first appeared in 2002 and then increased in prevalence and abundance over the remaining three surveys. Some species are therefore dynamic and both introductions and extinctions can be expected in ecological time. At higher taxonomic levels and for derived measures, year and host-age effects and their interactions with site are important. Our surveys emphasize that the site of capture is the major determinant of the species contributing to helminth community structure, providing some predictability in these systems.

  11. Chernobyl radiocesium in freshwater fish: Long-term dynamics and sources of variation

    Energy Technology Data Exchange (ETDEWEB)

    Sundbom, M. [Uppsala Univ., Dept. of Limnology, Uppsala (Sweden)

    2002-04-01

    The aim of this thesis was to investigate both the long-term temporal pattern and sources of individual variation for radiocesium in freshwater fish. The basis for the study is time series of {sup 137}Cs activity concentrations in fish from three lakes in the area North-west of Uppsala, Sweden that received considerable amounts of {sup 137}Cs from Chernobyl in may 1986. The lakes were Lake Ekholmssjoen, Lake Flatsjoen and Lake Siggeforasjoen, all small forest lakes, but with different morphometrical and chemical characteristics. The data were collected regularly, usually several times per year, during 1986-2000, using consistent methods. More than 7600 fish individuals from 7 species covering wide size ranges and feeding habits were analysed for {sup 137}Cs. For each fish was the length, weight, sex, and often the stomach contend recorded. The evaluation on long-term trends were based on data from all three lakes, while the study on sources of variation evaluated data from Lake Flatsjoen only. (au)

  12. Long-term dynamics of uranium reduction/reoxidation under low sulfate conditions

    Science.gov (United States)

    Komlos, John; Peacock, Aaron; Kukkadapu, Ravi K.; Jaffé, Peter R.

    2008-08-01

    The biological reduction and precipitation of uranium in groundwater has the potential to prevent uranium migration from contaminated sites. Although previous research has shown that uranium bioremediation is maximized during iron reduction, little is known on how long-term iron/uranium reducing conditions can be maintained. Questions also remain about the stability of uranium and other reduced species after a long-term biostimulation scheme is discontinued and oxidants (i.e., oxygen) re-enter the bioreduced zone. To gain further insights into these processes, four columns, packed with sediment containing iron as Fe-oxides (mainly Al-goethite) and silicate Fe (Fe-containing clays), were operated in the laboratory under field-relevant flow conditions to measure the long-term (>200 day) removal efficiency of uranium from a simulated groundwater during biostimulation with an electron donor (3 mM acetate) under low sulfate conditions. The biostimulation experiments were then followed by reoxidation of the reduced sediments with oxygen. During biostimulation, Fe(III) reduction occurred simultaneously with U(VI) reduction. Both Fe-oxides and silicate Fe(III) were partly reduced, and silicate Fe(III) reduction was detected only during the first half of the biostimulation phase while Fe-oxide reduction occurred throughout the whole biostimulation period. Mössbauer measurements indicated that the biogenic Fe(II) precipitate resulting from Fe-oxide reduction was neither siderite nor FeS 0.09 (mackinawite). U(VI) reduction efficiency increased throughout the bioreduction period, while the Fe(III) reduction gradually decreased with time. Effluent Fe(II) concentrations decreased linearly by only 30% over the final 100 days of biostimulation, indicating that bioreducible Fe(III) in the sediment was not exhausted at the termination of the experiment. Even though Fe(III) reduction did not change substantially with time, microorganisms not typically associated with Fe(III) and U

  13. 全球大地测量基准动态修正与服务%Dynamic Correction and Services of Global Geodetic Datum

    Institute of Scientific and Technical Information of China (English)

    成英燕; 曾安敏; 张鹏; 吕志平; 魏娜

    2016-01-01

    目标是建立高精度的全球动态地心坐标参考框架,形成我国独立自主的全球大地测量基准动态修正与服务体系,以满足国家经济建设、国防建设、科学研究以及测绘行业现代化对高精度动态基准日益增长的迫切需求。该年度首先从理论上对全球动态地心参考框架维持中观测数据的误差特性进行了分析,对不同观测数据融合时融合方法、函数模型、随机模型构建进行研究,对全球框架观测台站动态特性及稳定性进行分析,并基于多项原则对全球框架核心站点或控制站点进行优化选取,同时考虑到全球及我国框架的高精度维护,课题本年度还开展了基于多种大地测量技术手段确定地球质心的方法的研究,用全球分布GNSS观测台站10年观测数据,采用不同的技术和方法初步获得的地球质心的运动变化信息。在大网平差算法研究及软件实现上,研究了全球动态地心参考框架数据处理分布式计算技术,完成法方程层面及观测方程层面的参考框架数据处理分布式计算算法研究;完成多模卫星定位数据集成处理原型软件的模块设计和代码编写及大规模网数据组合和平差处理原型软件的模块设计和代码编写;研究基于国内大规模的GNSS区域网的地心坐标参考框架维持方法;为建立高精度全球动态地心坐标参考框架与维持奠定基础。%The project studys high-precision dynamic global geocentric reference frame for establishing an independent dynamic correction and service system of global geodetic datum to meet growing urgent needs of precision dynamic geocentric datum for economic construction, national defense, scientific research and modern surveying and mapping industry. In the first year, observation data error characteristics in maintainance of the global dynamic geocentric reference frame were analyzed; and data fusion method

  14. Double-Averaging Can Fail to Characterize the Long-Term Evolution of Lidov-Kozai Cycles & Derivation of an Analytical Correction

    CERN Document Server

    Luo, Liantong; Dong, Subo

    2016-01-01

    The double-averaging (DA) approximation is widely employed as the standard technique in studying the secular evolution of the hierarchical three-body system. We show that effects stemmed from the short-timescale oscillations ignored by DA can accumulate over long timescales and lead to significant errors in the long-term evolution of the Lidov-Kozai cycles. In particular, the conditions for having an orbital flip, where the inner orbit switches between prograde and retrograde with respect to the outer orbit and the associated extremely high eccentricities during the switch, can be modified significantly. The failure of DA can arise for a relatively strong perturber where the mass of the tertiary is considerable compared to the total mass of the inner binary. This issue can be relevant for astrophysical systems such as stellar triples, planets in stellar binaries, stellar-mass binaries orbiting massive black holes and moons of the planets perturbed by the Sun. We derive analytical equations for the short-term ...

  15. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Di Rosa Giuseppe

    2011-05-01

    Full Text Available Abstract Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA, during which no force was applied, a force field adaptation phase (CF, and a wash-out phase (WO in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. Results During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Conclusions Spatial abnormalities in children affected

  16. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    Science.gov (United States)

    2011-01-01

    Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects) with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA), during which no force was applied, a force field adaptation phase (CF), and a wash-out phase (WO) in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. Results During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Conclusions Spatial abnormalities in children affected by cerebral palsy may be

  17. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy.

    Science.gov (United States)

    Masia, Lorenzo; Frascarelli, Flaminia; Morasso, Pietro; Di Rosa, Giuseppe; Petrarca, Maurizio; Castelli, Enrico; Cappa, Paolo

    2011-05-21

    It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects) with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA), during which no force was applied, a force field adaptation phase (CF), and a wash-out phase (WO) in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Spatial abnormalities in children affected by cerebral palsy may be related not only to disturbance in

  18. Stand Dynamics, Humus Type and Water Balance Explain Aspen Long Term Productivity across Canada

    Directory of Open Access Journals (Sweden)

    Kenneth A. Anyomi

    2015-02-01

    Full Text Available This study examined the relative importance of soil, stand development and climate hypotheses in driving productivity for a species that is widely distributed in North America. Inventory plots, 3548 of such, either dominated by aspen or made up of species mixture of which aspen occurs in dominant canopy position were sampled along a longitudinal gradient from Quebec to British Columbia. Site index (SI, was used as a measure of productivity, and soil, climate and stand attributes were correlated with site index in order to determine their effects on productivity. Results show a decline in productivity with high moisture deficit. Soil humus correlates significantly with SI but does not sufficiently capture differential rates of litter deposition and decomposition effects over the long-term. Consequently, aspen composition, stand ageing, and stand structural changes dominate variability in productivity. Within the context where deciduous cover has being increasing, there are implications for forest productivity.

  19. Plasmid Dynamics in KPC-Positive Klebsiella pneumoniae during Long-Term Patient Colonization

    Directory of Open Access Journals (Sweden)

    Sean Conlan

    2016-06-01

    Full Text Available Carbapenem-resistant Klebsiella pneumoniae strains are formidable hospital pathogens that pose a serious threat to patients around the globe due to a rising incidence in health care facilities, high mortality rates associated with infection, and potential to spread antibiotic resistance to other bacterial species, such as Escherichia coli. Over 6 months in 2011, 17 patients at the National Institutes of Health (NIH Clinical Center became colonized with a highly virulent, transmissible carbapenem-resistant strain of K. pneumoniae. Our real-time genomic sequencing tracked patient-to-patient routes of transmission and informed epidemiologists’ actions to monitor and control this outbreak. Two of these patients remained colonized with carbapenemase-producing organisms for at least 2 to 4 years, providing the opportunity to undertake a focused genomic study of long-term colonization with antibiotic-resistant bacteria. Whole-genome sequencing studies shed light on the underlying complex microbial colonization, including mixed or evolving bacterial populations and gain or loss of plasmids. Isolates from NIH patient 15 showed complex plasmid rearrangements, leaving the chromosome and the blaKPC-carrying plasmid intact but rearranging the two other plasmids of this outbreak strain. NIH patient 16 has shown continuous colonization with blaKPC-positive organisms across multiple time points spanning 2011 to 2015. Genomic studies defined a complex pattern of succession and plasmid transmission across two different K. pneumoniae sequence types and an E. coli isolate. These findings demonstrate the utility of genomic methods for understanding strain succession, genome plasticity, and long-term carriage of antibiotic-resistant organisms.

  20. Thermal structure, composition, atmospheric dynamics and long-term evolution of irradiated exoplanets

    Science.gov (United States)

    Parmentier, Vivien

    2014-06-01

    More than a thousand exoplanets have been discovered over the last decade. Perhaps more excitingly, probing their atmospheres has become possible. We now have spectra of hot Jupiters like HD 189733b and HD 209458b, of Neptune-like planets like GJ1214b and even smaller planets are within reach. Most exoplanet atmospheric observations are averaged spatially, often over a hemi- sphere (during secondary eclipse) or over the limb of the planet (during transit). For favorable targets, longitudinal and latitudinal resolution can also be obtained with phase curve and secondary eclipse mapping techniques respectively. The closer the planet orbits to its star, the easier it is to observe. These hot planets strongly differ from the examples we have in our solar-system. Proper models of their atmospheres are challenging yet necessary to understand current and future observations. In this thesis, I use a hierarchy of atmospheric models to understand the interactions between the thermal structure, the composition, the atmospheric circulation and the long-term evolution of irradiated planets. In these planets, the large stellar irradiation dominates the energy budget of the atmosphere. It powers a strong atmospheric circulation that transports heat and material around the planet, driving the atmosphere out of thermal and chemical equilibrium and affecting its long-term evolution. Future instruments (Gaia, SPIRou, CHEOPS, TESS, PLATO etc) will discover many more planets that the next generation of telescopes (GMT, TMT, E-ELT or JWST) will characterize with an unprecedented accuracy. Models will be tested on a large sample of planets, extending the study of climates to exoplanets.

  1. Functional hoarseness in children: short-term play therapy with family dynamic counseling as therapy of choice.

    Science.gov (United States)

    Kollbrunner, Jürg; Seifert, Eberhard

    2013-09-01

    Children with nonorganic voice disorders (NVDs) are treated mainly using direct voice therapy techniques such as the accent method or glottal attack changes and indirect methods such as vocal hygiene and voice education. However, both approaches tackle only the symptoms and not etiological factors in the family dynamics and therefore often enjoy little success. The aim of the "Bernese Brief Dynamic Intervention" (BBDI) for children with NVD was to extend the effectiveness of pediatric voice therapies with a psychosomatic concept combining short-term play therapy with the child and family dynamic counseling of the parents. This study compares the therapeutic changes in three groups where different procedures were used, before intervention and 1 year afterward: counseling of parents (one to two consultations; n = 24), Brief Dynamic Intervention on the lines of the BBDI (three to five play therapy sessions with the child plus two to four sessions with the parents; n = 20), and traditional voice therapy (n = 22). A Voice Questionnaire for Parents developed by us with 59 questions to be answered on a four-point Likert scale was used to measure the change. According to the parents' assessment, a significant improvement in voice quality was achieved in all three methods. Counseling of parents (A) appears to have led parents to give their child more latitude, for example, they stopped nagging the child or demanding that he/she should behave strictly by the rules. After BBDI (B), the mothers were more responsive to their children's wishes and the children were more relaxed and their speech became livelier. At home, they called out to them less often at a distance, which probably improved parent-child dialog. Traditional voice therapy (C) seems to have had a positive effect on the children's social competence. BBDI seems to have the deepest, widest, and therefore probably the most enduring therapeutic effect on children with NVD.

  2. Understanding the nonlinear dynamics of driven particles in supercooled liquids in terms of an effective temperature

    Energy Technology Data Exchange (ETDEWEB)

    Schroer, Carsten F. E., E-mail: c.schroer@uni-muenster.de [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster (Germany); NRW Graduate School of Chemistry, Wilhelm-Klemm-Straße 10, 48149 Münster (Germany); Heuer, Andreas, E-mail: andheuer@uni-muenster.de [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster (Germany); Center of Nonlinear Science, Corresstraße 2, 48149 Münster (Germany); Center for Multiscale Theory and Computation, Corrensstraße 40, 48149 Münster (Germany)

    2015-12-14

    In active microrheology, the mechanical properties of a material are tested by adding probe particles which are pulled by an external force. In case of supercooled liquids, strong forcing leads to a thinning of the host material which becomes more pronounced as the system approaches the glass transition. In this work, we provide a quantitative theoretical description of this thinning behavior based on the properties of the Potential Energy Landscape (PEL) of a model glass-former. A key role plays the trap-like nature of the PEL. We find that the mechanical properties in the strongly driven system behave the same as in a quiescent system at an enhanced temperature, giving rise to a well-characterized effective temperature. Furthermore, this effective temperature turns out to be independent of the chosen observable and individually shows up in the thermodynamic and dynamic properties of the system. Based on this underlying theoretical understanding, we can estimate its dependence on temperature and force by the PEL-properties of the quiescent system. We furthermore critically discuss the relevance of effective temperatures obtained by scaling relations for the description of out-of-equilibrium situations.

  3. Long term dynamics beyond Neptune: secular models to study the regular motions

    CERN Document Server

    Saillenfest, Melaine; Tommei, Giacomo; Valsecchi, Giovanni B

    2016-01-01

    Two semi-analytical one-degree-of-freedom secular models are presented for the motion of small bodies beyond Neptune. A special attention is given to trajectories entirely exterior to the planetary orbits. The first one is the well-known non-resonant model of Kozai (1962) adapted to the transneptunian region. Contrary to previous papers, the dynamics is fully characterized with respect to the fixed parameters. A maximum perihelion excursion possible of 16.4 AU is determined. The second model handles the occurrence of a mean-motion resonance with one of the planets. In that case, the one-degree-of-freedom integrable approximation is obtained by postulating the adiabatic invariance, and is much more general and accurate than previous secular models found in the literature. It brings out in a plain way the possibility of perihelion oscillations with a very high amplitude. Such a model could thus be used in future studies to deeper explore that kind of motion. For complex resonant orbits (especially of type 1:k),...

  4. The role of reconsolidation and the dynamic process of long-term memory formation and storage

    Directory of Open Access Journals (Sweden)

    Cristina M Alberini

    2011-03-01

    Full Text Available It is becoming increasingly clear that the processes of memory formation and storage are exquisitely dynamic. Elucidating the nature and temporal evolution of the biological changes that accompany encoding, storage and retrieval is key to understand memory formation. For explicit or medial temporal lobe-dependent memories that form after a discrete event and are stored for a long time, the physical changes underlying the encoding and processing of the information (memory trace or engram remain in a fragile state for some time. However, over time, the new memory becomes increasingly resistant to disruption until it is consolidated. Retrieval or reactivation of an apparently consolidated memory can render the memory labile again, and reconsolidation is the process that occurs to mediate its restabilization. Reconsolidation also evolves with the age of the memory: Young memories are sensitive to postreactivation disruption, but older memories are more resistant. Why does a memory become labile again if it is retrieved or reactivated? Here I suggest that the main function of reconsolidation is to contribute to the lingering consolidation process and mediate memory strengthening. I also discuss the literature and results regarding the influence of the passage of time on the reconsolidation of memory. These points have important implications for the use of reconsolidation in therapeutic settings.

  5. Understanding the nonlinear dynamics of driven particles in supercooled liquids in terms of an effective temperature

    Science.gov (United States)

    Schroer, Carsten F. E.; Heuer, Andreas

    2015-12-01

    In active microrheology, the mechanical properties of a material are tested by adding probe particles which are pulled by an external force. In case of supercooled liquids, strong forcing leads to a thinning of the host material which becomes more pronounced as the system approaches the glass transition. In this work, we provide a quantitative theoretical description of this thinning behavior based on the properties of the Potential Energy Landscape (PEL) of a model glass-former. A key role plays the trap-like nature of the PEL. We find that the mechanical properties in the strongly driven system behave the same as in a quiescent system at an enhanced temperature, giving rise to a well-characterized effective temperature. Furthermore, this effective temperature turns out to be independent of the chosen observable and individually shows up in the thermodynamic and dynamic properties of the system. Based on this underlying theoretical understanding, we can estimate its dependence on temperature and force by the PEL-properties of the quiescent system. We furthermore critically discuss the relevance of effective temperatures obtained by scaling relations for the description of out-of-equilibrium situations.

  6. Long-term results of total repair of tetralogy of Fallot in adulthood: 35 years follow-up in 104 patients corrected at the age of 18 or older.

    Science.gov (United States)

    Nollert, G; Fischlein, T; Bouterwek, S; Böhmer, C; Dewald, O; Kreuzer, E; Welz, A; Netz, H; Klinner, W; Reichart, B

    1997-08-01

    Long-term survival after surgical repair of tetralogy of Fallot (TOF) is reported to be excellent if the patients are corrected in childhood. However, age at operation has been demonstrated as an important risk-factor. The aim of our study was to investigate whether adult patients also benefit from surgery. From December 1958 to May 1977, 739 patients underwent a correction of their TOF with pulmonary stenosis at our institution. Foreigners (n = 52) and those who moved to a foreign country (n = 13) were excluded from further analysis. Sixteen patients were lost during follow-up (98% complete). Of the remaining patient population (n = 658; mean age: 12.2 +/- 8.6 years; range 2-67 years), 104 patients were 18 years or older at the time of correction. Operative (n = 25) and one-year (n = 8) deaths were excluded for long-term calculations, resulting in a study group of 71 patients. Actuarial 10, 20, 30, and 35-year survival rates were 94%, 93%, 83%, and 72% respectively, and not different from normal life expectancy. The most common cause of death was congestive heart failure (n = 3), followed by myocardial infarction (n = 2) and sudden death (n = 2). Parameters influencing longterm survival could not be detected. At follow-up (mean 27.7 years), more than 80% (n = 48) of the 58 survivors reported themselves to be in NYHA functional class I or II and 95% (n = 55) were in a better condition than before the operation. Repair of tetralogy of Fallot in adulthood shows excellent results with normal life expectancy for the patients.

  7. Medial superior olivary neurons receive surprisingly few excitatory and inhibitory inputs with balanced strength and short-term dynamics.

    Science.gov (United States)

    Couchman, Kiri; Grothe, Benedikt; Felmy, Felix

    2010-12-15

    Neurons in the medial superior olive (MSO) process microsecond interaural time differences, the major cue for localizing low-frequency sounds, by comparing the relative arrival time of binaural, glutamatergic excitatory inputs. This coincidence detection mechanism is additionally shaped by highly specialized glycinergic inhibition. Traditionally, it is assumed that the binaural inputs are conveyed by many independent fibers, but such an anatomical arrangement may decrease temporal precision. Short-term depression on the other hand might enhance temporal fidelity during ongoing activity. For the first time we show that binaural coincidence detection in MSO neurons may require surprisingly few but strong inputs, challenging long-held assumptions about mammalian coincidence detection. This study exclusively uses adult gerbils for in vitro electrophysiology, single-cell electroporation and immunohistochemistry to characterize the size and short-term plasticity of inputs to the MSO. We find that the excitatory and inhibitory inputs to the MSO are well balanced both in strength and short-term dynamics, redefining this fastest of all mammalian coincidence detector circuits.

  8. Sex offender treatment outcome, actuarial risk, and the aging sex offender in Canadian corrections: a long-term follow-up.

    Science.gov (United States)

    Olver, Mark E; Nicholaichuk, Terry P; Gu, Deqiang; Wong, Stephen C P

    2013-08-01

    The present study is an examination of sex offender treatment outcome in a large national cohort of Canadian Federally incarcerated sex offenders followed up an average of 11.7 years postrelease. A brief actuarial risk scale (BARS), which predicted sexual and violent recidivism, was created for the purposes of the present study to control for risk-related differences between treated and untreated offenders. In total, 732 offenders were identified as having completed (n = 625) or not attended (n = 107) a sex offender treatment program and for whom sufficient information was available to complete the scale. Controlling for risk and individual differences in follow-up time using Cox regression survival analyses and an 8-year fixed follow-up period, treated sex offenders demonstrated significantly lower rates of violent, but not sexual, recidivism. When the treated and untreated groups were stratified by risk level, significant differences were observed only among moderate or high risk offenders. Some significant group differences also emerged on indicators of recidivism severity, with treated offenders demonstrating slower times to sexual reoffense and lower scores on a quantified metric of sexual and violent recidivism severity after controlling for risk. Differences in recidivism base rates between treated and untreated offenders were also larger in magnitude for younger offenders (i.e., under age 50 at release), than for older offenders; however, interactions between age and treatment were not found. The findings are consistent with the risk principle and have possible implications regarding the dynamic nature of sexual violence risk.

  9. Long-term tritium monitoring to study river basin dynamics: case of the Danube River basin

    Science.gov (United States)

    Aggarwal, Pradeep; Araguas, Luis; Groening, Manfred; Newman, Brent; Kurttas, Turker; Papesch, Wolfgang; Rank, Dieter; Suckow, Axel; Vitvar, Tomas

    2010-05-01

    During the last five decades, isotope concentrations (O-18, D, tritium) have been extensively measured in precipitation, surface- and ground-waters to derive information on residence times of water in aquifers and rivers, recharge processes, and groundwater dynamics. The unique properties of the isotopes of the water molecule as tracers are especially useful for understanding the retention of water in river basins, which is a key parameter for assessing water resources availability, addressing quality issues, investigating interconnections between surface- and ground-waters, and for predicting possible hydrological shifts related to human activities and climate change. Detailed information of the spatial and temporal changes of isotope contents in precipitation at a global scale was one of the initial aims of the Global Network of Isotopes in Precipitation (GNIP), which has provided a detailed chronicle of tritium and stable isotope contents in precipitation since the 1960s. Accurate information of tritium contents resulting of the thermonuclear atmospheric tests in the 1950s and 1960s is available in GNIP for stations distributed world-wide. Use of this dataset for hydrological dating or as an indicator of recent recharge has been extensive in shallow groundwaters. However, its use has been more limited in surface waters, due to the absence of specific monitoring programmes of tritium and stable isotopes in rivers, lakes and other surface water bodies. The IAEA has recently been compiling new and archival isotope data measured in groundwaters, rivers, lakes and other water bodies as part of its web based Water Isotope System for Data Analysis, Visualization and Electronic Retrieval (WISER). Recent additions to the Global Network of Isotopes in Rivers (GNIR) contained within WISER now make detailed studies in rivers possible. For this study, we are re-examining residence time estimates for the Danube in central Europe. Tritium data are available in GNIR from 15

  10. RNA-Seq reveals dynamic changes of gene expression in key stages of intestine regeneration in the sea cucumber Apostichopus japonicus. [corrected].

    Directory of Open Access Journals (Sweden)

    Lina Sun

    Full Text Available BACKGROUND: Sea cucumbers (Holothuroidea; Echinodermata have the capacity to regenerate lost tissues and organs. Although the histological and cytological aspects of intestine regeneration have been extensively studied, little is known of the genetic mechanisms involved. There has, however, been a renewed effort to develop a database of Expressed Sequence Tags (ESTs in Apostichopus japonicus, an economically-important species that occurs in China. This is important for studies on genetic breeding, molecular markers and special physiological phenomena. We have also constructed a library of ESTs obtained from the regenerative body wall and intestine of A. japonicus. The database has increased to ~30000 ESTs. RESULTS: We used RNA-Seq to determine gene expression profiles associated with intestinal regeneration in A. japonicus at 3, 7, 14 and 21 days post evisceration (dpe. This was compared to profiles obtained from a normally-functioning intestine. Approximately 5 million (M reads were sequenced in every library. Over 2400 up-regulated genes (>10% and over 1000 down-regulated genes (~5% were observed at 3 and 7dpe (log2Ratio ≥ 1, FDR ≤ 0.001. Specific "Go terms" revealed that the DEGs (Differentially Expressed Genes performed an important function at every regeneration stage. Besides some expected pathways (for example, Ribosome and Spliceosome pathway term, the "Notch signaling pathway," the "ECM-receptor interaction" and the "Cytokine-cytokine receptor interaction" were significantly enriched. We also investigated the expression profiles of developmental genes, ECM-associated genes and Cytoskeletal genes. Twenty of the most important differentially expressed genes (DEGs were verified by Real-time PCR, which resulted in a trend concordance of almost 100% between the two techniques. CONCLUSION: Our studies demonstrated dynamic changes in global gene expression during intestine regeneration and presented a series of candidate genes and enriched

  11. The role of tree-fall dynamics in long-term carbon storage of tropical peatlands

    Science.gov (United States)

    Dommain, R.; Cobb, A.; Joosten, H.; Glaser, P. H.; Chua, A.; Gandois, L.; Kai, F. M.; Noren, A. J.; Kamariah, A. S.; Su'ut, N. S.; Harvey, C. F.

    2015-12-01

    The forested peatlands of the Earth's tropical belt represent a major terrestrial carbon pool that may contain over 90 petagram C. However, the mechanisms that led to the build-up of this significant pool of carbon are poorly understood. Moreover, the rates of carbon uptake by peat accumulation in these tropical settings have rarely been quantified and natural variations in uptake on decadal to millennial scales are not well constrained. We studied carbon accumulation dynamics on these timescales of a peat swamp forest dominated by the dipterocarp Shorea albida - a unique forest type that, until recently, widely covered the lowlands of northwest Borneo. The impressive Shorea albida trees may reach heights of 70 m and are therefore strongly susceptible to windthrow and lightning. Such natural disturbances cause these trees to fall and uproot - excavating over 1 m deep holes into the peat that fill with water to become tip-up pools. The analysis of high-resolution aerial photographs and radiocarbon dated peat cores from our field site in Brunei together with the construction of a simulation model of peat accumulation allowed us to determine the role of tree-fall and tip-up pools in carbon storage. In a hectare of Shorea albida forest four tip-up pools form per decade. A pool completely fills with organic matter within 200 years according to our pollen record and a dated pool deposit stored 40 kg C m-2 of the total 110 kg C m-2 large local peat carbon pool. The carbon accumulation rates in these pools reach over 800 g C m-2 yr-1 - within the range of annual litterfall in dipterocarp forests. The simulation model indicates that up to 60% of the peat deposits under Shorea albida forests could be derived from infilled pools. Tip-up pools are therefore local hotspots for carbon storage in tropical forested peatlands.

  12. Dynamic simulation and metabolome analysis of long-term erythrocyte storage in adenine-guanosine solution.

    Directory of Open Access Journals (Sweden)

    Taiko Nishino

    Full Text Available Although intraerythrocytic ATP and 2,3-bisphophoglycerate (2,3-BPG are known as direct indicators of the viability of preserved red blood cells and the efficiency of post-transfusion oxygen delivery, no current blood storage method in practical use has succeeded in maintaining both these metabolites at high levels for long periods. In this study, we constructed a mathematical kinetic model of comprehensive metabolism in red blood cells stored in a recently developed blood storage solution containing adenine and guanosine, which can maintain both ATP and 2,3-BPG. The predicted dynamics of metabolic intermediates in glycolysis, the pentose phosphate pathway, and purine salvage pathway were consistent with time-series metabolome data measured with capillary electrophoresis time-of-flight mass spectrometry over 5 weeks of storage. From the analysis of the simulation model, the metabolic roles and fates of the 2 major additives were illustrated: (1 adenine could enlarge the adenylate pool, which maintains constant ATP levels throughout the storage period and leads to production of metabolic waste, including hypoxanthine; (2 adenine also induces the consumption of ribose phosphates, which results in 2,3-BPG reduction, while (3 guanosine is converted to ribose phosphates, which can boost the activity of upper glycolysis and result in the efficient production of ATP and 2,3-BPG. This is the first attempt to clarify the underlying metabolic mechanism for maintaining levels of both ATP and 2,3-BPG in stored red blood cells with in silico analysis, as well as to analyze the trade-off and the interlock phenomena between the benefits and possible side effects of the storage-solution additives.

  13. The NGS WikiBook: a dynamic collaborative online training effort with long-term sustainability.

    Science.gov (United States)

    Li, Jing-Woei; Bolser, Dan; Manske, Magnus; Giorgi, Federico Manuel; Vyahhi, Nikolay; Usadel, Björn; Clavijo, Bernardo J; Chan, Ting-Fung; Wong, Nathalie; Zerbino, Daniel; Schneider, Maria Victoria

    2013-09-01

    Next-generation sequencing (NGS) is increasingly being adopted as the backbone of biomedical research. With the commercialization of various affordable desktop sequencers, NGS will be reached by increasing numbers of cellular and molecular biologists, necessitating community consensus on bioinformatics protocols to tackle the exponential increase in quantity of sequence data. The current resources for NGS informatics are extremely fragmented. Finding a centralized synthesis is difficult. A multitude of tools exist for NGS data analysis; however, none of these satisfies all possible uses and needs. This gap in functionality could be filled by integrating different methods in customized pipelines, an approach helped by the open-source nature of many NGS programmes. Drawing from community spirit and with the use of the Wikipedia framework, we have initiated a collaborative NGS resource: The NGS WikiBook. We have collected a sufficient amount of text to incentivize a broader community to contribute to it. Users can search, browse, edit and create new content, so as to facilitate self-learning and feedback to the community. The overall structure and style for this dynamic material is designed for the bench biologists and non-bioinformaticians. The flexibility of online material allows the readers to ignore details in a first read, yet have immediate access to the information they need. Each chapter comes with practical exercises so readers may familiarize themselves with each step. The NGS WikiBook aims to create a collective laboratory book and protocol that explains the key concepts and describes best practices in this fast-evolving field.

  14. Short-term motor learning of dynamic balance control in children with probable Developmental Coordination Disorder.

    Science.gov (United States)

    Jelsma, Dorothee; Ferguson, Gillian D; Smits-Engelsman, Bouwien C M; Geuze, Reint H

    2015-03-01

    To explore the differences in learning a dynamic balance task between children with and without probable Developmental Coordination Disorder (p-DCD) from different cultural backgrounds. Twenty-eight Dutch children with DCD (p-DCD-NL), a similar group of 17 South African children (p-DCD-SA) and 21 Dutch typically developing children (TD-NL) participated in the study. All children performed the Wii Fit protocol. The slope of the learning curve was used to estimate motor learning for each group. The protocol was repeated after six weeks. Level of motor skill was assessed with the Movement ABC-2. No significant difference in motor learning rate was found between p-DCD-NL and p-DCD-SA, but the learning rate of children with p-DCD was slower than the learning rate of TD children. Speed-accuracy trade off, as a way to improve performance by slowing down in the beginning was only seen in the TD children, indicating that TD children and p-DCD children used different strategies. Retention of the level of learned control of the game after six weeks was found in all three groups after six weeks. The learning slope was associated with the level of balance skill for all children. This study provides evidence that children with p-DCD have limitations in motor learning on a complex balance task. In addition, the data do not support the contention that learning in DCD differs depending on cultural background. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Locating Temporal Functional Dynamics of Visual Short-Term Memory Binding using Graph Modular Dirichlet Energy

    Science.gov (United States)

    Smith, Keith; Ricaud, Benjamin; Shahid, Nauman; Rhodes, Stephen; Starr, John M.; Ibáñez, Augustin; Parra, Mario A.; Escudero, Javier; Vandergheynst, Pierre

    2017-02-01

    Visual short-term memory binding tasks are a promising early marker for Alzheimer’s disease (AD). To uncover functional deficits of AD in these tasks it is meaningful to first study unimpaired brain function. Electroencephalogram recordings were obtained from encoding and maintenance periods of tasks performed by healthy young volunteers. We probe the task’s transient physiological underpinnings by contrasting shape only (Shape) and shape-colour binding (Bind) conditions, displayed in the left and right sides of the screen, separately. Particularly, we introduce and implement a novel technique named Modular Dirichlet Energy (MDE) which allows robust and flexible analysis of the functional network with unprecedented temporal precision. We find that connectivity in the Bind condition is less integrated with the global network than in the Shape condition in occipital and frontal modules during the encoding period of the right screen condition. Using MDE we are able to discern driving effects in the occipital module between 100–140 ms, coinciding with the P100 visually evoked potential, followed by a driving effect in the frontal module between 140–180 ms, suggesting that the differences found constitute an information processing difference between these modules. This provides temporally precise information over a heterogeneous population in promising tasks for the detection of AD.

  16. Short-term dynamics of culturable bacteria in a soil amended with biotransformed dry olive residue.

    Science.gov (United States)

    Siles, J A; Pascual, J; González-Menéndez, V; Sampedro, I; García-Romera, I; Bills, G F

    2014-03-01

    Dry olive residue (DOR) transformation by wood decomposing basidiomycetes (e.g. Coriolopsis floccosa) is a possible strategy for eliminating the liabilities related to the use of olive oil industry waste as an organic soil amendment. The effects of organic fertilization with DOR on the culturable soil microbiota are largely unknown. Therefore, the objectives of this study were to measure the short-term effects of DOR and C. floccosa-transformed DOR on the culturable bacterial soil community, while at the same time documenting the bacterial diversity of an agronomic soil in the southeastern Iberian Peninsula. The control soil was compared with the same soil treated with DOR and with C. floccosa-transformed DOR for 0, 30 and 60 days. Impact was measured from total viable cells and CFU counts, as well as the isolation and characterization of 900 strains by fatty acid methyl ester profiles and 16S rRNA partial sequencing. The bacterial diversity was distributed between Actinobacteria, Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Bacilli, Sphingobacteria and Cytophagia. Analysis of the treatments and controls demonstrated that soil amendment with untransformed DOR produced important changes in bacterial density and diversity. However, when C. floccosa-transformed DOR was applied, bacterial proliferation was observed but bacterial diversity was less affected, and the distribution of microorganisms was more similar to the unamended soil.

  17. Long-term population dynamics of breeding bird species in the German Wadden Sea area

    Science.gov (United States)

    Vauk, Gottfried; Prüter, Johannes; Hartwig, Eike

    1989-09-01

    For no other group of organisms in coastal areas are there so exact and long-term data available as there are for seabirds. Since the beginning of the 20th century, documentation of population size, especially for species breeding in colonies from the groups gulls, terns and auks, is almost complete. These species act as bio-indicators, and data on fluctuations in their population size are useful as they reflect changes in the state of the marine ecosystem. The population development of some of these seabird species (Herring Gull, Guillemot, Common, Arctic and Sandwich Tern) from the German North Sea coast, which primarily feed on fish, is given. Common to all these species is an exponential increase in numbers in recent years (1970 1985). Possible causes for this development, e.g. pressure from enemies or competitors, availability of breeding places, anthropogenic stress and mortality factors, as well as the direct and indirect anthropogenic-influenced changes in the trophic system due to the increasing eutrophication of coastal waters, are evaluated. Signs of a collapse in the stocks of seabrids resulting from environmental pollution are discussed. Consequences resulting from the ecosystem changes, such as reduction of nutrient discharge into the North Sea and the expansion of biological monitoring, are described.

  18. Binding neutral information to emotional contexts: Brain dynamics of long-term recognition memory.

    Science.gov (United States)

    Ventura-Bort, Carlos; Löw, Andreas; Wendt, Julia; Moltó, Javier; Poy, Rosario; Dolcos, Florin; Hamm, Alfons O; Weymar, Mathias

    2016-04-01

    There is abundant evidence in memory research that emotional stimuli are better remembered than neutral stimuli. However, effects of an emotionally charged context on memory for associated neutral elements is also important, particularly in trauma and stress-related disorders, where strong memories are often activated by neutral cues due to their emotional associations. In the present study, we used event-related potentials (ERPs) to investigate long-term recognition memory (1-week delay) for neutral objects that had been paired with emotionally arousing or neutral scenes during encoding. Context effects were clearly evident in the ERPs: An early frontal ERP old/new difference (300-500 ms) was enhanced for objects encoded in unpleasant compared to pleasant and neutral contexts; and a late central-parietal old/new difference (400-700 ms) was observed for objects paired with both pleasant and unpleasant contexts but not for items paired with neutral backgrounds. Interestingly, objects encoded in emotional contexts (and novel objects) also prompted an enhanced frontal early (180-220 ms) positivity compared to objects paired with neutral scenes indicating early perceptual significance. The present data suggest that emotional--particularly unpleasant--backgrounds strengthen memory for items encountered within these contexts and engage automatic and explicit recognition processes. These results could help in understanding binding mechanisms involved in the activation of trauma-related memories by neutral cues.

  19. Dynamics and cultural specifics of information needs under conditions of long-term space flight

    Science.gov (United States)

    Feichtinger, Elena; Shved, Dmitry; Gushin, Vadim

    Life in conditions of space flight or chamber study with prolonged isolation is associated with lack of familiar stimuli (sensory deprivation), monotony, significant limitation of communication, and deficit of information and media content (Myasnikov V.I., Stepanova S.I. et al., 2000). Fulfillment of a simulation experiment or flight schedule implies necessity of performance of sophisticated tasks and decision making with limited means of external support. On the other hand, the “stream” of information from the Mission Control (MC) and PI’s (reminders about different procedures to be performed, requests of reports, etc.) is often inadequate to communication needs of crewmembers. According to the theory of “information stress” (Khananashvili M.M., 1984), a distress condition could be formed if: a) it’s necessary to process large amounts of information and make decisions under time pressure; b) there is a prolonged deficit of necessary (e.g. for decision making) information. Thus, we suppose that one of the important goals of psychological support of space or space simulation crews should be forming of favorable conditions of information environment. For that purpose, means of crew-MC information exchange (quantitative characteristics and, if possible, content of radiograms, text and video messages, etc.) should be studied, as well as peculiarities of the crewmembers’ needs in different information and media content, and their reactions to incoming information. In the space simulation experiment with 520-day isolation, communication of international crew with external parties had been studied. Dynamics of quantitative and content characteristics of the crew’s messages was related to the experiment’s stage, presence of “key” events in the schedule (periods of high autonomy, simulated “planetary landing”, etc.), as well as to events not related to the experiment (holidays, news, etc.). It was shown that characteristics of information exchange

  20. Short-term variations in the dynamics of Bowdoin Glacier in northwestern Greenland

    Science.gov (United States)

    Minowa, Masahiro; Sugiyama, Shin; Sawagaki, Takanobu; Tsutaki, Shun; Sakakibara, Daiki

    2016-04-01

    Tidewater glaciers in Greenland ice sheet are rapidly retreating by under the influence of changes in ice dynamics. For example, Bowdoin Glacier began rapid retreat in 2008, which was accompanied by significant acceleration near the glacier front. Submarine melting and ice-mélange weakening are suspected as triggering mechanisms of the rapid retreat of tidewater glaciers in the Greenland ice sheet, but details of processes at the ice-ocean interface are poorly understood. To better understand these processes, we measured ice-front position of Bowdoin Glacier in northwestern Greenland and glacier/ice-mélange movement in front of the glacier. The glacier/ice-mélange measurement was performed by processing 3-hourly photographs taken by a time-lapse camera operated over two years since July 2013. We also operated a dual-frequency GPS at 3 km from the calving front to measure ice speed from May to July in 2014 and 2015. The image analysis revealed clear seasonal variations in the ice-front position with an amplitude of ~200 m. Seasonal changes were also observed in ice speed along the center of the glacier (amplitude ~50%). During summer, the ice-front position was relatively stable, but retreated occasionally by large calving events. These events occurred near upwelling of subglacial discharge, where a large submarine melt rate is expected. The glacier began to advance in September approximately when daily mean air temperature dropped below 0°C. The glacier advanced the most in winter when the fjord was covered by ice-mélange. After winter, extended portion of the glacier rapidly disintegrated by a few calving events. Such event coincided with onset of ice-mélange movement in front of the glacier. This movement occurs when air temperature above 0°C and high wind speed were observed, suggesting the calving event was due to decrease in the mechanical support from the ice-mélange. These results indicate both ice-mélange and submarine melting play roles in

  1. Daily prediction of short-term trends of crude oil prices using neural networks exploiting multimarket dynamics

    Institute of Scientific and Technical Information of China (English)

    Heping PAN; Imad HAIDAR; Siddhivinayak KULKARNI

    2009-01-01

    This paper documents a systematic investigation on the predictability of short-term trends of crude oil prices on a daily basis. In stark contrast with longer-term predic-tions of crude oil prices, short-term prediction with time horizons of 1-3 days posits an important problem that is quite different from what has been studied in the litera-ture. The problem of such short-term predicability is tackled through two aspects. The first is to examine the existence of linear or nonlinear dynamic processes in crude oil prices.This sub-problem is addressed with statistical analysis in-volving the Brock-Dechert-Scheinkman test for nonlinearity.The second aspect is to test the capability of artificial neu-ral networks (ANN) for modeling the implicit nonlinearity for prediction. Four experimental models are designed and tested with historical data: (1) using only the lagged returns of filtered crude oil prices as input to predict the returns of the next days; this is used as the benchmark, (2) using only the information set of filtered crude oil futures price as in-put, (3) combining the inputs from the benchmark and sec-ond models, and (4) combing the inputs from the benchmark model and the intermarket information. In order to filter out the noise in the original price data, the moving averages of prices are used for all the experiments. The results provided sufficient evidence to the predictability of crude oil prices using ANN with an out-of-sample hit rate of 80%, 70%, and 61% for each of the next three days' trends.

  2. Modeling organic carbon dynamics and cadmium fate in long-term sludge-amended soil.

    Science.gov (United States)

    Bergkvist, Petra; Jarvis, Nicholas

    2004-01-01

    A model is described that may help to resolve uncertainty and controversy over the long-term consequences of sludge applications to arable land, especially with regard to the effects of sludge adsorption characteristics on trace metal solubility and bioavailability (e.g., the sludge "time bomb" or sludge "protection" hypotheses). Mass balances of organic and inorganic material derived from sludge and crop residues are simulated. Each pool has a potentially different adsorption affinity for trace metals, and this leads to changes in the adsorption capacity of sludge-amended soil that influence leaching and crop uptake. Model simulations were compared with measured changes in organic carbon and ethylenediaminetetraacetic acid (EDTA)-extractable cadmium contents in a clay loam soil following 41 years of sludge applications. The model adequately reproduced the data, although discrepancies in the vertical distribution of Cd were attributed to the effects of macropore transport and root-uptake driven recirculation. A Monte Carlo sensitivity analysis demonstrated that the most important parameters affecting leaching and crop uptake were the Cd loading and parameters controlling adsorption, especially the partition coefficient for sludge-derived inorganic material and the exponent regulating the effect of pH on sorption. Scenario simulations show that no general conclusions can be drawn with respect to the validity of the sludge "time bomb" and sludge "protection" hypotheses. Either may occur, or neither, depending on three key system parameters: the ratio of sludge adsorption capacity to the initial adsorption capacity of the soil, the proportion of the sludge adsorption capacity contributed by the inorganic fraction, and the sludge Cd loading.

  3. LTS and FS inhibitory interneurons, short-term synaptic plasticity, and cortical circuit dynamics.

    Directory of Open Access Journals (Sweden)

    Itai Hayut

    2011-10-01

    Full Text Available Somatostatin-expressing, low threshold-spiking (LTS cells and fast-spiking (FS cells are two common subtypes of inhibitory neocortical interneuron. Excitatory synapses from regular-spiking (RS pyramidal neurons to LTS cells strongly facilitate when activated repetitively, whereas RS-to-FS synapses depress. This suggests that LTS neurons may be especially relevant at high rate regimes and protect cortical circuits against over-excitation and seizures. However, the inhibitory synapses from LTS cells usually depress, which may reduce their effectiveness at high rates. We ask: by which mechanisms and at what firing rates do LTS neurons control the activity of cortical circuits responding to thalamic input, and how is control by LTS neurons different from that of FS neurons? We study rate models of circuits that include RS cells and LTS and FS inhibitory cells with short-term synaptic plasticity. LTS neurons shift the RS firing-rate vs. current curve to the right at high rates and reduce its slope at low rates; the LTS effect is delayed and prolonged. FS neurons always shift the curve to the right and affect RS firing transiently. In an RS-LTS-FS network, FS neurons reach a quiescent state if they receive weak input, LTS neurons are quiescent if RS neurons receive weak input, and both FS and RS populations are active if they both receive large inputs. In general, FS neurons tend to follow the spiking of RS neurons much more closely than LTS neurons. A novel type of facilitation-induced slow oscillations is observed above the LTS firing threshold with a frequency determined by the time scale of recovery from facilitation. To conclude, contrary to earlier proposals, LTS neurons affect the transient and steady state responses of cortical circuits over a range of firing rates, not only during the high rate regime; LTS neurons protect against over-activation about as well as FS neurons.

  4. Long-term dynamics and characteristics of snags created for wildlife habitat

    Science.gov (United States)

    Barry, Amy M.; Hagar, Joan; Rivers, James W.

    2017-01-01

    Snags provide essential habitat for numerous organisms and are therefore critical to the long-term maintenance of forest biodiversity. Resource managers often use snag creation to mitigate the purposeful removal of snags at the time of harvest, but information regarding how created snags change over long timescales (>20 y) is absent from the literature. In this study, we evaluated the extent to which characteristics of large (>30 cm diameter at breast height [DBH]) Douglas-fir (Pseudotsuga menziesii) snags created by topping had changed after 25–27 y. We also tested whether different harvest treatments and snag configurations influenced present-day snag characteristics. Of 690 snags created in 1989–1991, 91% remained standing during contemporary surveys and 65% remained unbroken along the bole. Although most snags were standing, we detected increased bark loss and breaking along the bole relative to prior surveys conducted on the same pool of snags. Although snag characteristics were not strongly influenced by snag configuration, we found that snags in one harvest treatment (group selection) experienced less bark loss and had lower evidence of use by cavity-nesting birds (as measured by total cavity cover) relative to snags created with clearcut and two-story harvest treatments. Our results indicate that Douglas-fir snags created by topping can remain standing for long time-periods (≥25 y) in managed forests, and that the influence of harvest treatment on decay patterns and subsequent use by wildlife is an important consideration when intentionally creating snags for wildlife habitat.

  5. The dynamics of blood biochemical parameters in cosmonauts during long-term space flights

    Science.gov (United States)

    Markin, Andrei; Strogonova, Lubov; Balashov, Oleg; Polyakov, Valery; Tigner, Timoty

    Most of the previously obtained data on cosmonauts' metabolic state concerned certain stages of the postflight period. In this connection, all conclusions, as to metabolism peculiarities during the space flight, were to a large extent probabilistic. The purpose of this work was study of metabolism characteristics in cosmonauts directly during long-term space flights. In the capillary blood samples taken from a finger, by "Reflotron IV" biochemical analyzer, "Boehringer Mannheim" GmbH, Germany, adapted to weightlessness environments, the activity of GOT, GPT, CK, gamma-GT, total and pancreatic amylase, as well as concentration of hemoglobin, glucose, total bilirubin, uric acid, urea, creatinine, total, HDL- and LDL cholesterol, triglycerides had been determined. HDL/LDL-cholesterol ratio also was computed. The crewmembers of 6 main missions to the "Mir" orbital station, a total of 17 cosmonauts, were examined. Biochemical tests were carryed out 30-60 days before lounch, and in the flights different stages between the 25-th and the 423-rd days of flights. In cosmonauts during space flight had been found tendency to increase, in compare with basal level, GOT, GPT, total amylase activity, glucose and total cholesterol concentration, and tendency to decrease of CK activity, hemoglobin, HDL-cholesterol concentration, and HDL/LDL — cholesterol ratio. Some definite trends in variations of other determined biochemical parameters had not been found. The same trends of mentioned biochemical parameters alterations observed in majority of tested cosmonauts, allows to suppose existence of connection between noted metabolic alterations with influence of space flight conditions upon cosmonaut's body. Variations of other studied blood biochemical parameters depends on, probably, pure individual causes.

  6. Empirical correction of multifilter rotating shadowband radiometer (MFRSR) aerosol optical depths for the aerosol forward scattering and development of a long-term integrated MFRSR-Cimel dataset at Lampedusa.

    Science.gov (United States)

    di Sarra, Alcide; Sferlazzo, Damiano; Meloni, Daniela; Anello, Fabrizio; Bommarito, Carlo; Corradini, Stefano; De Silvestri, Lorenzo; Di Iorio, Tatiana; Monteleone, Francesco; Pace, Giandomenico; Piacentino, Salvatore; Pugnaghi, Sergio

    2015-04-01

    Aerosol optical properties have been measured on the island of Lampedusa (35.5°N, 12.6°E) with seven-band multifilter rotating shadowband radiometers (MFRSRs) and a CE 318 Cimel sunphotometer (part of the AERONET network) since 1999. Four different MFRSRs have operated since 1999. The Cimel sunphotometer has been operational for a short period in 2000 and in 2003-2006 and 2010-present. Simultaneous determinations of the aerosol optical depth (AOD) from the two instruments were compared over a period of almost 4 years at several wavelengths between 415 and 870 nm. This is the first long-term comparison at a site strongly influenced by desert dust and marine aerosols and characterized by frequent cases of elevated AOD. The datasets show a good agreement, with MFRSR underestimating the Cimel AOD in cases with low Ångström exponent; the underestimate decreases for increasing wavelength and increases with AOD. This underestimate is attributed to the effect of aerosol forward scattering on the relatively wide field of view of the MFRSR. An empirical correction of the MFRSR data was implemented. After correction, the mean bias (MB) between MFRSR and Cimel simultaneous AOD determinations is always smaller than 0.004, and the root mean square difference is ≤0.031 at all wavelengths. The MB between MFRSR and Cimel monthly averages (for months with at least 20 days with AOD determinations) is 0.0052. Thus, by combining the MFRSR and Cimel observations, an integrated long-term series is obtained, covering the period 1999-present, with almost continuous measurements since early 2002. The long-term data show a small (nonstatistically significant) decreasing trend over the period 2002-2013, in agreement with independent observations in the Mediterranean. The integrated Lampedusa dataset will be used for aerosol climatological studies and for verification of satellite observations and model analyses.

  7. PROCEEDINGS OF THE WORKSHOP ON LHC INTERACTION REGION CORRECTION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    FISCHER,W.; WEI,J.

    1999-09-02

    The Workshop on LHC Interaction Region Correction Systems was held at Brookhaven National Laboratory, Upton, New York, on 6 and 7 May 1999. It was attended by 25 participants from 5 institutions. The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region quadrupoles and dipoles. In three sessions the workshop addressed the field quality of the these magnets, reviewed the principles and efficiency of global and local correction schemes and finalized a corrector layout. The session on Field Quality Issues, chaired by J. Strait (FNAL), discussed the progress made by KEK and FNAL in achieving the best possible field quality in the interaction region quadrupoles. Results of simulation studies were presented that assess the effects of magnetic field errors with simulation studies. Attention was given to the uncertainties in predicting and measuring field errors. The session on Global Correction, chaired by J.-P. Koutchouk (CERN), considered methods of reducing the nonlinear detuning or resonance driving terms in the accelerator one-turn map by either sorting or correcting. The session also discussed the crossing angle dependence of the dynamic aperture and operational experience from LEP. The session on Local Correction, chaired by T. Taylor (CERN), discussed the location, strength and effectiveness of multipole correctors in the interaction regions for both proton and heavy ion operation. Discussions were based on technical feasibility considerations and dynamic aperture requirements. The work on linear corrections in the interaction regions was reviewed.

  8. Long-term effect of mineral fertilizers and amendments on microbial dynamics in an alfisol of Western Himalayas.

    Science.gov (United States)

    Mahajan, S; Kanwar, S S; Sharma, S P

    2007-03-01

    The microbial dynamics expressed in terms of culturable microbial populations i.e. bacteria, fungi, actinomycetes and Azotobacter were measured after 33 years of continuous application of mineral fertilizers and amendments to an acid alfisol. The bacterial, fungal and Azotobacter populations were maximum in plots treated with mineral fertilizers and FYM (100%NPK+FYM) while actinomycetes population was maximum in mineral fertilizes and lime treated plots (100%NPK+Lime). The bacterial population decreased and fungal population increased with increasing levels of NPK i.e. from 50% to 150%NPK. Bacillus species of bacteria and Gliocladium, Aspergillus and Rhizopus species of fungi were the main dominating culturable microorganisms in all the treatments. The FYM and lime amended plots sustained crop productivity and microbial populations at higher levels than rest of the mineral fertilizer treatments. The nitrogenous fertilizers alone had the most deleterious effect on crop productivity and the biological soil environment.

  9. A Dynamical Model for Information Retrieval and Emergence of Scale-Free Clusters in a Long Term Memory Network

    CERN Document Server

    Licata, Ignazio

    2010-01-01

    The classical forms of knowledge representation fail when a strong dynamical interconnection between system and environment comes into play. We propose here a model of information retrieval derived from the Kintsch-Ericsson scheme, based upon a long term memory (LTM) associative net whose structure changes in time according to the textual content of the analyzed documents. Both the theoretical analysis carried out by using simple statistical tools and the tests show the appearing of typical power-laws and the net configuration as a scale-free graph. The information retrieval from LTM shows that the entire system can be considered to be an information amplifier which leads to the emergence of new cognitive structures. It has to be underlined that the expanding of the semantic domain regards the user-network as a whole system.

  10. Physical simulation of the long-term dynamic action of a plasma beam on a space debris object

    Science.gov (United States)

    Shuvalov, Valentin A.; Gorev, Nikolai. B.; Tokmak, Nikolai A.; Kochubei, Galina S.

    2017-03-01

    A methodology is developed for physical (laboratory) simulation of the long-term dynamic action of plasma beam high-energy ions on a space debris object with the aim of removing it to a lower orbit followed by its burning in the Earth's atmosphere. The methodology is based on the use of a criterion for the equivalence of two plasma beam exposure regimes (in the Earth' ionosphere and in laboratory conditions) and an accelerated test procedure in what concerns space debris object material sputtering and space debris object erosion by a plasma beam in the Earth's ionosphere. The space debris coating material (blanket thermal insulation) sputtering yield and normal and tangential momentum transfer coefficients are determined experimentally as a function of the ion energy and the ion beam incidence angle.

  11. Dynamical behaviors of the shock compacton in the nonlinearly Schrödinger equation with a source term

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jiuli, E-mail: yjl@ujs.edu.cn; Zhao, Liuwei

    2014-11-07

    In this paper, the dynamics from the shock compacton to chaos in the nonlinearly Schrödinger equation with a source term is investigated in detail. The existence of unclosed homoclinic orbits which are not connected with the saddle point indicates that the system has a discontinuous fiber solution which is a shock compacton. We prove that the shock compacton is a weak solution. The Melnikov technique is used to detect the conditions for the occurrence from the shock compacton to chaos and further analysis of the conditions for chaos suppression. The results show that the system turns to chaos easily under external disturbances. The critical parameter values for chaos appearing are obtained analytically and numerically using the Lyapunov exponents and the bifurcation diagrams.

  12. An analysis of the long term hydrological dynamics of the Careser, a rapidly retreating Alpine glacier.

    Science.gov (United States)

    Stella, Elisa; Meneghetti, Erica; Cainelli, Oscar; Bellin, Alberto

    2017-04-01

    Alpine glaciers are shrinking at a relentless pace, as an effect of the increasing temperature and the concomitant reduction of snowfall that the Alpine region experienced in the last 40 years. The impact of these changes is relevant, given the importance of the Alps from ecological and economical points of view. While the ubiquitous reduction of glaciers mass through the Alps has been reported in a number of studies, its effect on streamflow is less studied, mainly because much less data are available on streamflow emerging from glaciers. In the present work we analyze a long streamflow time series, recorded since the 70s, in the Careser creek emerging from the Careser Glacier, which mass has been monitored since 1920, first discontinuously and then continuously from 1967. Because of these long-term observations, the Careser has been classified as one of the reference glaciers by the World Glacier Monitoring Service, which provides balances data every two years. We performed a comprehensive analysis of multiscale variations of precipitation, temperature, water discharge and glacier mass. In addition we explored the correlations between streamflow and climatic drivers at monthly and subdaily scales. We observed significant changes in the timing of streamflow, with anticipated snow melting and a reduction of summer runoff, while at the annual scale the increase of ice-melting offsets runoff reduction caused by less winter precipitation falling as snow. In fact, in most years since the 1990 ice melts from beginning of May to October, thereby causing a dramatic reduction of the glacier volume. However, in the last years the significant reduction of the glacier surface, attenuated this tendency to increase the total annual runoff volume. At the sub-daily scale we observed a progressive increase of the difference between the maximum and minimum water discharge. Overall the hydrological regime changes significantly as an effect of the rise in temperature and the lower

  13. Long-term dynamics of death rates of emphysema, asthma, and pneumonia and improving air quality

    Directory of Open Access Journals (Sweden)

    Kravchenko J

    2014-06-01

    Full Text Available Julia Kravchenko,1 Igor Akushevich,2 Amy P Abernethy,3 Sheila Holman,4 William G Ross Jr,5 H Kim Lyerly1,6 1Department of Surgery, 2Center for Population Health and Aging, 3Duke Clinical Research Institute, Duke University Medical Center, Duke University, Durham, 4Division of Air Quality, North Carolina Department of Environment and Natural Resources, Raleigh, 5Nicholas School of the Environment, 6Department of Pathology, Duke University Medical Center, Duke University, Durham, NC, USA Background: The respiratory tract is a major target of exposure to air pollutants, and respiratory diseases are associated with both short- and long-term exposures. We hypothesized that improved air quality in North Carolina was associated with reduced rates of death from respiratory diseases in local populations. Materials and methods: We analyzed the trends of emphysema, asthma, and pneumonia mortality and changes of the levels of ozone, sulfur dioxide (SO2, nitrogen dioxide (NO2, carbon monoxide (CO, and particulate matters (PM2.5 and PM10 using monthly data measurements from air-monitoring stations in North Carolina in 1993–2010. The log-linear model was used to evaluate associations between air-pollutant levels and age-adjusted death rates (per 100,000 of population calculated for 5-year age-groups and for standard 2000 North Carolina population. The studied associations were adjusted by age group-specific smoking prevalence and seasonal fluctuations of disease-specific respiratory deaths. Results: Decline in emphysema deaths was associated with decreasing levels of SO2 and CO in the air, decline in asthma deaths–with lower SO2, CO, and PM10 levels, and decline in pneumonia deaths–with lower levels of SO2. Sensitivity analyses were performed to study potential effects of the change from International Classification of Diseases (ICD-9 to ICD-10 codes, the effects of air pollutants on mortality during summer and winter, the impact of approach when only

  14. LONG-TERM DYNAMICS OF RADIONUCLIDE VERTICAL MIGRATION IN SOILS OF THE CHERNOBYL NUCLEAR POWER PLANT EXCLUSION ZONE

    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E

    2009-11-19

    The radioactive fallout from the Chernobyl Nuclear Power Plant (ChNPP) accident consisted of fuel and condensation components. An important radioecological task associated with the late phase of the accident is to evaluate the dynamics of radionuclide mobility in soils. Identification of the variability (or invariability) in the radionuclide transfer parameters makes it possible to (1) accurately predict migration patterns and biological availability of radionuclides and (2) evaluate long-term exposure trends for the population who may reoccupy the remediated abandoned areas. In 1986-1987, a number of experimental plots were established within various tracts of the fallout plume to assist with the determination of the long-term dynamics of radionuclide vertical migration in the soils. The transfer parameters for {sup 137}Cs, {sup 90}Sr, and {sup 239,240}Pu in the soil profile, as well as their ecological half-time of the radionuclide residence (T{sub 1/2}{sup ecol}) values in the upper 5-cm thick soil layers of different grasslands were estimated at various times since the accident. Migration characteristics in the grassland soils tend to decrease as follows: {sup 90}Sr > {sup 137}Cs {ge} {sup 239,240}Pu. It was found that the {sup 137}Cs absolute T{sub 1/2}{sup ecol} values are 3-7 times higher than its radioactive decay half-life value. Therefore, changes in the exposure dose resulting from the soil deposited {sup 137}Cs now depend only on its radioactive decay. The {sup 90}Sr T{sub 1/2}{sup ecol} values for the 21st year after the fallout tend to decrease, indicating an intensification of its migration capabilities. This trend appears consistent with a pool of mobile {sup 90}Sr forms that grows over time due to destruction of the fuel particles.

  15. Dynamic Changes of IsiA-Containing Complexes during Long-Term Iron Deficiency in Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Ma, Fei; Zhang, Xin; Zhu, Xi; Li, Tianpei; Zhan, Jiao; Chen, Hui; He, Chenliu; Wang, Qiang

    2017-01-09

    Iron stress-induced protein A (IsiA), a major chlorophyll-binding protein in the thylakoid membrane, is significantly induced under iron deficiency conditions. Using immunoblot analysis and 77 K fluorescence spectroscopy combined with sucrose gradient fractionation, we monitored dynamic changes of IsiA-containing complexes in Synechocystis sp. PCC 6803 during exposure to long-term iron deficiency. Within 3 days of exposure to iron deficiency conditions, the initially induced free IsiA proteins preferentially conjugated to PS I trimer to form IsiA18-PS I trimers, which serve as light energy collectors for efficiently transmitting energy to PS I. With prolonged iron deficiency, IsiA proteins assembled either into IsiA aggregates or into two other types of IsiA-PS I supercomplexes, namely IsiA-PS I high fluorescence supercomplex (IHFS) and IsiA-PS I low fluorescence supercomplex (ILFS). Further analysis revealed a role for IsiA as an energy dissipater in the IHFS and as an energy collector in the ILFS. The trimeric structure of PS I mediated by PsaL was found to be indispensable for the formation of IHFS/ILFS. Dynamic changes in IsiA-containing complexes in cyanobacteria during long-term iron deficiency may represent an adaptation to iron limitation stress for flexible light energy distribution, which balances electron transfer between PS I and PS II, thus minimizing photooxidative damage. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  16. Are the long-term effects of mesobrowsers on woodland dynamics substitutive or additive to those of elephants?

    Science.gov (United States)

    O'Kane, Christopher A. J.; Duffy, Kevin J.; Page, Bruce R.; Macdonald, David W.

    2011-09-01

    The large spectrum of existing literature on browser-woodland dynamics, both from savanna and temperate biomes, converges towards concluding that all browsers importantly impact woody plants. In this context a crucial question in the current debate about reintroducing elephant culling, is whether the long-term effects of elephants and mesobrowsers are similar. If the two groups impact the same woody species in the same habitats, sufficiently high biomass-densities of mesobrowsers may, following removal of elephants, continue to heavily impact earlier life-history stages of the same suite of woody plants that elephant impacted, preventing these species from maturing. Thus, as existing mature trees die from natural causes and fade from the system, a similar end-point for woodland structure and composition is achieved. We reviewed 49 years of literature on the savanna browser guild, performing a meta-analysis on the disparate data on the guild's woody plant species use (3677 records) and habitat use (894 records). Mesobrowsers' and elephants' extensive overlap in habitat use and staple woody species diet, together with evidence of their influencing each others' abundance and of their dietary separation increasing with resource depletion, implies that the two groups impact the same core woody species in the same habitats. It therefore seems probable that high biomass-density mesobrowsers may have a long-term substitutive effect to that of elephant on woodland dynamics. Consequently management wanting a particular state of savanna woodland, should consider the biomass-density of both groups, rather than just focus on the system's perceived keystone species. Such principles may also apply to temperate and other systems.

  17. Relative information contributions of model vs. data to short- and long-term forecasts of forest carbon dynamics.

    Science.gov (United States)

    Weng, Ensheng; Luo, Yiqi

    2011-07-01

    Biogeochemical models have been used to evaluate long-term ecosystem responses to global change on decadal and century time scales. Recently, data assimilation has been applied to improve these models for ecological forecasting. It is not clear what the relative information contributions of model (structure and parameters) vs. data are to constraints of short- and long-term forecasting. In this study, we assimilated eight sets of 10-year data (foliage, woody, and fine root biomass, litter fall, forest floor carbon [C], microbial C, soil C, and soil respiration) collected from Duke Forest into a Terrestrial Ecosystem model (TECO). The relative information contribution was measured by Shannon information index calculated from probability density functions (PDFs) of carbon pool sizes. The null knowledge without a model or data was defined by the uniform PDF within a prior range. The relative model contribution was information content in the PDF of modeled carbon pools minus that in the uniform PDF, while the relative data contribution was the information content in the PDF of modeled carbon pools after data was assimilated minus that before data assimilation. Our results showed that the information contribution of the model to constrain carbon dynamics increased with time whereas the data contribution declined. The eight data sets contributed more than the model to constrain C dynamics in foliage and fine root pools over the 100-year forecasts. The model, however, contributed more than the data sets to constrain the litter, fast soil organic matter (SOM), and passive SOM pools. For the two major C pools, woody biomass and slow SOM, the model contributed less information in the first few decades and then more in the following decades than the data. Knowledge of relative information contributions of model vs. data is useful for model development, uncertainty analysis, future data collection, and evaluation of ecological forecasting.

  18. Examination of the rheological properties of stirred joghurt during the long-term storage by using dynamic oscillation method

    Directory of Open Access Journals (Sweden)

    Milica Vilušić

    2003-07-01

    Full Text Available In this work the rheological properties of stirred yoghurt during the longterm storage at 4 and 8°C were investigated. The optimal quantity of additives, in order to increase dry matter content (whole milk powder and whey protein-lactalbumin, was preliminary determined and the fermentation was performed. During 42 days, i.e., 1st, 7th, 14th, 21st, 28th, 35th and 42nd day of storage of stirred yoghurt, in refrigerator at 4 and 8°C, the changes of pH value, acidity and rheological properties by using of dynamic oscillation method were observed. Results of this work indicated that an addition of whole milk powder and whey protein have an influence on rheological properties of stirred yoghurt. The long-term storage of stirred yoghurt and the results of dynamic oscilations showed permanently higher G’storage (elasticity modulus, where elastic properties of viscoelastic products dominate, in comparison with the G” loss (viscosity modulus. Increased moduls of elasticy and viscosity, as function of time, permanently occurs at pH value 4.00 and lower, as an indication of alteration of long casein chains in the coagulum structure. Different temperatures of storage had no influence on changes of rheological properties of examinated types of stirred yoghur. The relation of above mentioned moduls of elasticy and viscosity kept the same increasing tendency.

  19. Inducing Herd Immunity against Seasonal Influenza in Long-Term Care Facilities through Employee Vaccination Coverage: A Transmission Dynamics Model

    Directory of Open Access Journals (Sweden)

    Aaron M. Wendelboe

    2015-01-01

    Full Text Available Introduction. Vaccinating healthcare workers (HCWs in long-term care facilities (LTCFs may effectively induce herd immunity and protect residents against influenza-related morbidity and mortality. We used influenza surveillance data from all LTCFs in New Mexico to validate a transmission dynamics model developed to investigate herd immunity induction. Material and Methods. We adjusted a previously published transmission dynamics model and used surveillance data from an active system among 76 LTCFs in New Mexico during 2006-2007 for model validation. We used a deterministic compartmental model with a stochastic component for transmission between residents and HCWs in each facility in order to simulate the random variation expected in such populations. Results. When outbreaks were defined as a dichotomous variable, our model predicted that herd immunity could be induced. When defined as an attack rate, the model demonstrated a curvilinear trend, but insufficiently strong to induce herd immunity. The model was sensitive to changes in the contact parameter β but was robust to changes in the visitor contact probability. Conclusions. These results further elucidate previous studies’ findings that herd immunity may not be induced by vaccinating HCWs in LTCFs; however, increased influenza vaccination coverage among HCWs reduces the probability of influenza infection among residents.

  20. [Dynamics of microbial biomass P and its affecting factors in a long-te