Boundary-layer transition prediction using a simplified correlation-based model
Directory of Open Access Journals (Sweden)
Xia Chenchao
2016-02-01
Full Text Available This paper describes a simplified transition model based on the recently developed correlation-based γ-Reθt transition model. The transport equation of transition momentum thickness Reynolds number is eliminated for simplicity, and new transition length function and critical Reynolds number correlation are proposed. The new model is implemented into an in-house computational fluid dynamics (CFD code and validated for low and high-speed flow cases, including the zero pressure flat plate, airfoils, hypersonic flat plate and double wedge. Comparisons between the simulation results and experimental data show that the boundary-layer transition phenomena can be reasonably illustrated by the new model, which gives rise to significant improvements over the fully laminar and fully turbulent results. Moreover, the new model has comparable features of accuracy and applicability when compared with the original γ-Reθt model. In the meantime, the newly proposed model takes only one transport equation of intermittency factor and requires fewer correlations, which simplifies the original model greatly. Further studies, especially on separation-induced transition flows, are required for the improvement of the new model.
Boundary-layer transition prediction using a simplified correlation-based model
Institute of Scientific and Technical Information of China (English)
Xia Chenchao; Chen Weifang
2016-01-01
This paper describes a simplified transition model based on the recently developed correlation-based c ? Reht transition model. The transport equation of transition momentum thick-ness Reynolds number is eliminated for simplicity, and new transition length function and critical Reynolds number correlation are proposed. The new model is implemented into an in-house com-putational fluid dynamics (CFD) code and validated for low and high-speed flow cases, including the zero pressure flat plate, airfoils, hypersonic flat plate and double wedge. Comparisons between the simulation results and experimental data show that the boundary-layer transition phenomena can be reasonably illustrated by the new model, which gives rise to significant improvements over the fully laminar and fully turbulent results. Moreover, the new model has comparable features of accuracy and applicability when compared with the original c ? Reht model. In the meantime, the newly proposed model takes only one transport equation of intermittency factor and requires fewer correlations, which simplifies the original model greatly. Further studies, especially on separation-induced transition flows, are required for the improvement of the new model.
Directory of Open Access Journals (Sweden)
Carolina Bonivento
2014-01-01
Full Text Available The ability to reproduce visually presented actions has been studied through neuropsychological observations of patients with ideomotor apraxia. These studies include attempts to understand the neural basis of action reproduction based on lesion–symptom mapping in different patient groups. While there is a convergence of evidence that areas in the parietal and frontal lobes within the left hemisphere are involved in the imitation of a variety of actions, questions remain about whether the results generalize beyond the imitation of tool use and whether the presence of a strong grasp component of the action is critical. Here we used voxel-based lesion–symptom mapping to assess the neural substrates of imitating meaningful (familiar, MF and meaningless (unfamiliar, ML tool-related (transitive and non-tool related (intransitive actions. The analysis showed that the left parietal cortex was involved in the imitation of transitive gestures, regardless of whether they were meaningful or not. In addition there was poor reproduction of meaningless actions (both transitive and intransitive following damage of the right frontal cortex. These findings suggest a role of right frontal regions in processing of unfamiliar actions.
Bonivento, Carolina; Rothstein, Pia; Humphreys, Glyn; Chechlacz, Magdalena
2014-01-01
The ability to reproduce visually presented actions has been studied through neuropsychological observations of patients with ideomotor apraxia. These studies include attempts to understand the neural basis of action reproduction based on lesion-symptom mapping in different patient groups. While there is a convergence of evidence that areas in the parietal and frontal lobes within the left hemisphere are involved in the imitation of a variety of actions, questions remain about whether the results generalize beyond the imitation of tool use and whether the presence of a strong grasp component of the action is critical. Here we used voxel-based lesion-symptom mapping to assess the neural substrates of imitating meaningful (familiar, MF) and meaningless (unfamiliar, ML) tool-related (transitive) and non-tool related (intransitive) actions. The analysis showed that the left parietal cortex was involved in the imitation of transitive gestures, regardless of whether they were meaningful or not. In addition there was poor reproduction of meaningless actions (both transitive and intransitive) following damage of the right frontal cortex. These findings suggest a role of right frontal regions in processing of unfamiliar actions.
A Physically Based Correlation of Irradiation-Induced Transition Temperature Shifts for RPV Steels
Energy Technology Data Exchange (ETDEWEB)
Eason, Ernest D. [Modeling and Computing Services, LLC; Odette, George Robert [UCSB; Nanstad, Randy K [ORNL; Yamamoto, Takuya [ORNL
2007-11-01
The reactor pressure vessels (RPVs) of commercial nuclear power plants are subject to embrittlement due to exposure to high-energy neutrons from the core, which causes changes in material toughness properties that increase with radiation exposure and are affected by many variables. Irradiation embrittlement of RPV beltline materials is currently evaluated using Regulatory Guide 1.99 Revision 2 (RG1.99/2), which presents methods for estimating the shift in Charpy transition temperature at 30 ft-lb (TTS) and the drop in Charpy upper shelf energy (ΔUSE). The purpose of the work reported here is to improve on the TTS correlation model in RG1.99/2 using the broader database now available and current understanding of embrittlement mechanisms. The USE database and models have not been updated since the publication of NUREG/CR-6551 and, therefore, are not discussed in this report. The revised embrittlement shift model is calibrated and validated on a substantially larger, better-balanced database compared to prior models, including over five times the amount of data used to develop RG1.99/2. It also contains about 27% more data than the most recent update to the surveillance shift database, in 2000. The key areas expanded in the current database relative to the database available in 2000 are low-flux, low-copper, and long-time, high-fluence exposures, all areas that were previously relatively sparse. All old and new surveillance data were reviewed for completeness, duplicates, and discrepancies in cooperation with the American Society for Testing and Materials (ASTM) Subcommittee E10.02 on Radiation Effects in Structural Materials. In the present modeling effort, a 10% random sample of data was reserved from the fitting process, and most aspects of the model were validated with that sample as well as other data not used in calibration. The model is a hybrid, incorporating both physically motivated features and empirical calibration to the U.S. power reactor surveillance
Modelling conditional correlations of asset returns: A smooth transition approach
DEFF Research Database (Denmark)
Silvennoinen, Annastiina; Teräsvirta, Timo
In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM......-test is derived to test the constancy of correlations and LM- and Wald tests to test the hypothesis of partially constant correlations. Analytical expressions for the test statistics and the required derivatives are provided to make computations feasible. An empirical example based on daily return series of ve...... frequently traded stocks in the S&P 500 stock index completes the paper....
Magnetic correlations in doped transition metal oxides
Energy Technology Data Exchange (ETDEWEB)
Aeppli, G. [AT and T Bell Labs., Murray Hill, NJ (United States); Bao, W.; Broholm, C. [Johns Hopkins Univ., Baltimore, MD (United States)] [and others
1995-02-15
The authors review recent reactor- and spallation-source-based neutron scattering experiments on the magnetic fluctuations and order in a variety of doped transition metal oxides. In particular, data are shown for the NiO chain compound, Y{sub 2{minus}x}Ca{sub x}BaNiO{sub 5}, the two-dimensional cuprate superconductors La{sub 2{minus}x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3} O{sub 6+x}, and the classical three-dimensional ``Mott-Hubbard`` system V{sub 2{minus}y}O{sub 3}.
Pairing correlations and transitions in nuclear systems
Belic, A; Hjorth-Jensen, M
2004-01-01
We discuss several pairing-related phenomena in nuclear systems, ranging from superfluidity in neutron stars to the gradual breaking of pairs in finite nuclei. We describe recent experimental evidence that points to a relation between pairing and phase transitions (or transformations) in finite nuclear systems. A simple pairing interaction model is used in order to study and classify an eventual pairing phase transition in finite fermionic systems such as nuclei. We show that systems with as few as 10-16 fermions can exhibit clear features reminiscent of a phase transition.
Correlation analysis of transitional processes of chronorhythms
Strinadko, Marina M.; Timochko, Katerina B.; Strinadko, Olena M.; Abramov, Igor V.
1999-11-01
The biological system reaction on spasmodic change of a phase of sine wave revolting force is investigated. The model researches for the biosystem unit that is described by linear differential equation of the second order are carried out. Possibility of time asymmetry in adaptation and transitional processes of biological units, at spasmodic change of phase identical modulo and opposite on the sign is shown. The residual in time of adaptation depends on state of biosystem's unit at the moment of perturbation.
Antiferromagnetic phase transition and spin correlations in NiO
DEFF Research Database (Denmark)
Chatterji, Tapan; McIntyre, G.J.; Lindgård, Per-Anker
2009-01-01
We have investigated the antiferromagnetic (AF) phase transition and spin correlations in NiO by high-temperature neutron diffraction below and above TN. We show that AF phase transition is a continuous second-order transition within our experimental resolution. The spin correlations manifested...... by this process. We determined the critical exponents =0.328±0.002 and =0.64±0.03 and the Néel temperature TN=530±1 K. These critical exponents suggest that NiO should be regarded as a 3dXY system...
Institute of Scientific and Technical Information of China (English)
YAN Jun-Yan; WANG Lin-Cheng; YI Xue-Xi
2011-01-01
We study the quantum discord dynamics of a bipartite composite system in the presence of a dissipative environment and investigate the effect of the interaction between the two subsystems. The results show that the interaction can influence the sudden transition between the quantum correlation and the classical correlation and for the maximally mixed marginals initial states, the sudden transition regime will always exist. The entanglements are also discussed in comparison to the quantum discord in describing the quantum correlations.%@@ We study the quantum discord dynamics of a bipartite composite system in the presence of a dissipative envi- ronment and investigate the effect of the interaction between the two subsystems.The results show that the interaction can influence the sudden transition between the quantum correlation and the classical correlation and for the maximally mixed marginals initial states, the sudden transition regime will always exist.The entangle- ments are also discussed in comparison to the quantum discord in describing the quantum correlations.
Kinetics of first-order phase transitions with correlated nuclei
Rickman, J. M.; Barmak, K.
2017-02-01
We demonstrate that the time evolution of a first-order phase transition may be described quite generally in terms of the statistics of point processes, thereby providing an intuitive framework for visualizing transition kinetics. A number of attractive and repulsive nucleation scenarios is examined followed by isotropic domain growth at a constant rate This description holds for both uncorrelated and correlated nuclei, and may be employed to calculate the nonequilibrium, n -point spatiotemporal correlations that characterize the transition. Furthermore, it is shown that the interpretation of the one-point function in terms of a stretched-exponential, Kolmogorov-Johnson-Mehl-Avrami result is problematic in the case of correlated nuclei, but that the calculation of higher-order correlation functions permits one to distinguish among various nucleation scenarios.
METABALL-BASED TRANSITION SURFACES
Institute of Scientific and Technical Information of China (English)
Li Lingfeng; Tan Jianrong; Chen Yuanpeng
2005-01-01
Metaball-based constraint deformation technique is used to change the definition of r, the straight-line distance from a space point to a constraint center in the original calculation of the potential function. By replacing the parameter of the parametrized surface w with the straight-line distance r, a method of building transition surfaces according to connected boundary curves and skeleton curves is proposed. The method has no restrictions on boundary curves that control the space shapes of transition surfaces or on types of skeleton curves, thus transition surfaces, which reach C1 continuity and are more abundant in shapes and natural, can be obtained.
Phase transitions for scaling of structural correlations in directed networks
van der Hoorn, Pim
2015-01-01
Analysis of degree-degree dependencies in complex networks, and their impact on processes on networks requires null models, i.e. models that generate uncorrelated scale-free networks. Most models to date however show structural negative dependencies, caused by finite size effects. We analyze the behavior of these structural negative degree-degree dependencies, using rank based correlation measures, in the directed Erased Configuration Model. We obtain expressions for the scaling as a function of the exponents of the distributions. Moreover, we show that this scaling undergoes a phase transition, where one region exhibits scaling related to the natural cut-off of the network while another region has scaling similar to the structural cut-off for uncorrelated networks. By establishing the speed of convergence of these structural dependencies we are able to asses statistical significance of degree-degree dependencies on finite complex networks when compared to networks generated by the directed Erased Configurati...
Energy Technology Data Exchange (ETDEWEB)
Lu, Yi-Lin [Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Dong, Shengjie [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Zhou, Baozeng [Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Zhao, Hui [Department of Physics, Tianjin Normal University, Tianjin 300387 (China); Wu, Ping, E-mail: pingwu@tju.edu.cn [Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China)
2015-06-15
Using first-principles density functional theory calculations, we have investigated the electronic structure and magnetic properties of four superlattices (MO){sub 1}/(MX){sub 1} (001) (M=Ca and Sr; X=N and C). Our results show that compared with standard GGA approach, the GGA plus effective U{sub eff} scheme can correct electronic structure and magnetic properties in some extent. With enhancing electronic correlation, for (CaO){sub 1}/(CaN){sub 1}, (SrO){sub 1}/(SrN){sub 1}, and (SrO){sub 1}/(SrC){sub 1}, the bands across Fermi level are divided into two parts and the shape of isotropic spherical spin atmosphere becomes anisotropic dumbbell-like with specific orientation, accompanying metal-insulator transitions. For (CaO){sub 1}/(CaC){sub 1}, the states just smearing with the Fermi level shift to lower energy region below Fermi level, indicating the transformation from a nearly half metal to an actual half metal occurs. The different behavior of (CaO){sub 1}/(CaC){sub 1} compared with three other compounds may be caused by the larger ionization energy of calcium than that of strontium and the smaller electronegativity of carbon than that of nitrogen. - Highlights: • The magnetic behaviors of four d{sup 0} superlattices are investigated. • The enhanced electronic correlation influences the magnetic properties. • (CaO){sub 1}/(CaC){sub 1} transforms from a nearly half metal to an actual half metal. • The other three compounds transform from half metals to magnetic insulators.
Zhao, Jinggeng; Liu, Haozhe; Ehm, Lars; Dong, Dawei; Chen, Zhiqiang; Liu, Qingqing; Hu, Wanzheng; Wang, Nanlin; Jin, Changqing
2013-07-15
High-pressure angle-dispersive X-ray diffraction experiments on iron-based superconductor Ce(O(0.84)F(0.16))FeAs were performed up to 54.9 GPa at room temperature. A tetragonal to tetragonal isostructural phase transition starts at about 13.9 GPa, and a new high-pressure phase has been found above 33.8 GPa. At pressures above 19.9 GPa, Ce(O(0.84)F(0.16))FeAs completely transforms to a high-pressure tetragonal phase, which remains in the same tetragonal structure with a larger a-axis and smaller c-axis than those of the low-pressure tetragonal phase. The structure analysis shows a discontinuity in the pressure dependences of the Fe-As and Ce-(O, F) bond distances, as well as the As-Fe-As and Ce-(O, F)-Ce bond angles in the transition region, which correlates with the change in T(c) of this compound upon compression. The isostructural phase transition in Ce(O(0.84)F(0.16))FeAs leads to a drastic drop in the superconducting transition temperature T(c) and restricts the superconductivity at low temperature. For the 1111-type iron-based superconductors, the structure evolution and following superconductivity changes under compression are related to the radius of lanthanide cations in the charge reservoir layer.
Disorder- and correlation-driven metal-insulator transitions
Balzer, Matthias; Potthoff, Michael
2004-01-01
Metal-insulator transitions driven by disorder (Delta) and/or by electron correlations (U) are investigated within the Anderson-Hubbard model with local binary-alloy disorder using a simple but consistent mean-field approach. The Delta-U phase diagram is derived and discussed for T=0 and finite temperatures.
Effect of correlations on controllability transition in network control.
Nie, Sen; Wang, Xu-Wen; Wang, Bing-Hong; Jiang, Luo-Luo
2016-04-11
The network control problem has recently attracted an increasing amount of attention, owing to concerns including the avoidance of cascading failures of power-grids and the management of ecological networks. It has been proven that numerical control can be achieved if the number of control inputs exceeds a certain transition point. In the present study, we investigate the effect of degree correlation on the numerical controllability in networks whose topological structures are reconstructed from both real and modeling systems, and we find that the transition point of the number of control inputs depends strongly on the degree correlation in both undirected and directed networks with moderately sparse links. More interestingly, the effect of the degree correlation on the transition point cannot be observed in dense networks for numerical controllability, which contrasts with the corresponding result for structural controllability. In particular, for directed random networks and scale-free networks, the influence of the degree correlation is determined by the types of correlations. Our approach provides an understanding of control problems in complex sparse networks.
Stochastic transitions into silence cause noise correlations in cortical circuits.
Mochol, Gabriela; Hermoso-Mendizabal, Ainhoa; Sakata, Shuzo; Harris, Kenneth D; de la Rocha, Jaime
2015-03-17
The spiking activity of cortical neurons is highly variable. This variability is generally correlated among nearby neurons, an effect commonly interpreted to reflect the coactivation of neurons due to anatomically shared inputs. Recent findings, however, indicate that correlations can be dynamically modulated, suggesting that the underlying mechanisms are not well understood. Here, we investigate the hypothesis that correlations are dominated by neuronal coinactivation: the occurrence of brief silent periods during which all neurons in the local network stop firing. We recorded spiking activity from large populations of neurons in the auditory cortex of anesthetized rats across different brain states. During spontaneous activity, the reduction of correlation accompanying brain state desynchronization was largely explained by a decrease in the density of the silent periods. The presentation of a stimulus caused an initial drop of correlations followed by a rebound, a time course that was mimicked by the instantaneous silence density. We built a rate network model with fluctuation-driven transitions between a silent and an active attractor and assumed that neurons fired Poisson spike trains with a rate following the model dynamics. Variations of the network external input altered the transition rate into the silent attractor and reproduced the relation between correlation and silence density found in the data, both in spontaneous and evoked conditions. This suggests that the observed changes in correlation, occurring gradually with brain state variations or abruptly with sensory stimulation, are due to changes in the likeliness of the microcircuit to transiently cease firing.
Ford, Eric B.; Fabrycky, Daniel C.; Steffen, Jason H.; Carter, Joshua A.; Fressin, Francois; Holman, Matthew Jon; Lissauer, Jack J.; Moorhead, Althea V.; Morehead, Robert C.; Ragozzine, Darin; Rowe, Jason F.; Welsh, William F.; Allen, Christopher; Batalha, Natalie M.; Borucki, William J.
2012-01-01
We present a new method for confirming transiting planets based on the combination of transit timingn variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data se...
Cluster identification based on correlations.
Schulman, L S
2012-04-01
The problem addressed is the identification of cooperating agents based on correlations created as a result of the joint action of these and other agents. A systematic method for using correlations beyond second moments is developed. The technique is applied to a didactic example, the identification of alphabet letters based on correlations among the pixels used in an image of the letter. As in this example, agents can belong to more than one cluster. Moreover, the identification scheme does not require that the patterns be known ahead of time.
Bao, Junwei Lucas; Odoh, Samuel O; Gagliardi, Laura; Truhlar, Donald G
2017-02-14
We study the performance of multiconfiguration pair-density functional theory (MC-PDFT) and multireference perturbation theory for the computation of the bond dissociation energies in 12 transition-metal-containing diatomic molecules and three small transition-metal-containing polyatomic molecules and in two transition-metal dimers. The first step is a multiconfiguration self-consistent-field calculation, for which two choices must be made: (i) the active space and (ii) its partition into subspaces, if the generalized active space formulation is used. In the present work, the active space is chosen systematically by using three correlated-participating-orbitals (CPO) schemes, and the partition is chosen by using the separated-pair (SP) approximation. Our calculations show that MC-PDFT generally has similar accuracy to CASPT2, and the active-space dependence of MC-PDFT is not very great for transition-metal-ligand bond dissociation energies. We also find that the SP approximation works very well, and in particular SP with the fully translated BLYP functional SP-ftBLYP is more accurate than CASPT2. SP greatly reduces the number of configuration state functions relative to CASSCF. For the cases of FeO and NiO with extended-CPO active space, for which complete active space calculations are unaffordable, SP calculations are not only affordable but also of satisfactory accuracy. All of the MC-PDFT results are significantly better than the corresponding results with broken-symmetry spin-unrestricted Kohn-Sham density functional theory. Finally we test a perturbation theory method based on the SP reference and find that it performs slightly worse than CASPT2 calculations, and for most cases of the nominal-CPO active space, the approximate SP perturbation theory calculations are less accurate than the much less expensive SP-PDFT calculations.
Yang-Mills correlators across the deconfinement phase transition
Reinosa, U.; Serreau, J.; Tissier, M.; Tresmontant, A.
2017-02-01
We compute the finite temperature ghost and gluon propagators of Yang-Mills theory in the Landau-DeWitt gauge. The background field that enters the definition of the latter is intimately related with the (gauge-invariant) Polyakov loop and serves as an equivalent order parameter for the deconfinement transition. We use an effective gauge-fixed description where the nonperturbative infrared dynamics of the theory is parametrized by a gluon mass which, as argued elsewhere, may originate from the Gribov ambiguity. In this scheme, one can perform consistent perturbative calculations down to infrared momenta, which have been shown to correctly describe the phase diagram of Yang-Mills theories in four dimensions as well as the zero-temperature correlators computed in lattice simulations. In this article, we provide the one-loop expressions of the finite temperature Landau-DeWitt ghost and gluon propagators for a large class of gauge groups and present explicit results for the SU(2) case. These are substantially different from those previously obtained in the Landau gauge, which corresponds to a vanishing background field. The nonanalyticity of the order parameter across the transition is directly imprinted onto the propagators in the various color modes. In the SU(2) case, this leads, for instance, to a cusp in the electric and magnetic gluon susceptibilities as well as similar signatures in the ghost sector. We mention the possibility that such distinctive features of the transition could be measured in lattice simulations in the background field gauge studied here.
Using Hand Grip Force as a Correlate of Longitudinal Acceleration Comfort for Rapid Transit Trains.
Guo, Beiyuan; Gan, Weide; Fang, Weining
2015-07-02
Longitudinal acceleration comfort is one of the essential metrics used to evaluate the ride comfort of train. The aim of this study was to investigate the effectiveness of using hand grip force as a correlate of longitudinal acceleration comfort of rapid transit trains. In the paper, a motion simulation system was set up and a two-stage experiment was designed to investigate the role of the grip force on the longitudinal comfort of rapid transit trains. The results of the experiment show that the incremental grip force was linearly correlated with the longitudinal acceleration value, while the incremental grip force had no correlation with the direction of the longitudinal acceleration vector. The results also show that the effects of incremental grip force and acceleration duration on the longitudinal comfort of rapid transit trains were significant. Based on multiple regression analysis, a step function model was established to predict the longitudinal comfort of rapid transit trains using the incremental grip force and the acceleration duration. The feasibility and practicably of the model was verified by a field test. Furthermore, a comparative analysis shows that the motion simulation system and the grip force based model were valid to support the laboratory studies on the longitudinal comfort of rapid transit trains.
Ford, Eric B; Steffen, Jason H; Carter, Joshua A; Fressin, Francois; Holman, Matthew J; Lissauer, Jack J; Moorhead, Althea V; Morehead, Robert C; Ragozzine, Darin; Rowe, Jason F; Welsh, William F; Allen, Christopher; Batalha, Natalie M; Borucki, William J; Bryson, Stephen T; Buchhave, Lars A; Burke, Christopher J; Caldwell, Douglas A; Charbonneau, David; Clarke, Bruce D; Cochran, William D; Désert, Jean-Michel; Endl, Michael; Everett, Mark E; Fischer, Debra A; Gautier, Thomas N; Gilliland, Ron L; Jenkins, Jon M; Haas, Michael R; Horch, Elliott; Howell, Steve B; Ibrahim, Khadeejah A; Isaacson, Howard; Koch, David G; Latham, David W; Li, Jie; Lucas, Philip; MacQueen, Phillip J; Marcy, Geoffrey W; McCauliff, Sean; Mullally, Fergal R; Quinn, Samuel N; Quintana, Elisa; Shporer, Avi; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Torres, Guillermo; Twicken, Joseph D; Wohler, Bill
2012-01-01
We present a new method for confirming transiting planets based on the combination of transit timingn variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the transit timing variations of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:...
Reveal quantum correlation in complementary bases
Shengjun Wu; Zhihao Ma; Zhihua Chen; Sixia Yu
2013-01-01
An essential feature of genuine quantum correlation is the simultaneous existence of correlation in complementary bases. We reveal this feature of quantum correlation by defining measures based on invariance under a basis change. For a bipartite quantum state, the classical correlation is the maximal correlation present in a certain optimum basis, while the quantum correlation is characterized as a series of residual correlations in the mutually unbiased bases. Compared with other approaches ...
Correlations in rare-earth transition-metal permanent magnets
Energy Technology Data Exchange (ETDEWEB)
Skomski, R., E-mail: rskomski@neb.rr.com; Manchanda, P. [Department of Physics and Astronomy and NCMN, University of Nebraska, Lincoln, Nebraska 68508 (United States); Kashyap, A. [School of Basic Science, IIT Mandi, Mandi, Himachal Pradesh (India)
2015-05-07
It is investigated how electron-electron correlations affect the intrinsic properties of rare-earth transition-metal magnets. Focusing on orbital moment and anisotropy, we perform model calculations for 3d-4f alloys and density-functional theory (DFT) calculations for NdCo{sub 5}. On an independent-electron level, the use of a single Slater determinant with broken spin symmetry introduces Hund's rule correlations, which govern the behavior of rare-earth ions and of alloys described by the local spin density approximation (LSDA) and LSDA + U approximations to DFT. By contrast, rare-earth ions in intermetallics involve configuration interactions between two or more Slater determinants and lead to phenomena such as spin-charge distribution. Analyzing DFT as a Legendre transformation and using Bethe's crystal-field theory, we show that the corresponding density functionals are very different from familiar LSDA-type expressions and outline the effect of spin-charge separation on the magnetocrystalline anisotropy.
Strong electron correlations in biomimetic transition metal molecules
Labute, Montiago Xavier
The first-row transition metals (Fe, Co, V,...) are key players in the active sites of proteins and enzymes responsible for diverse biological processes such as NO regulation and photosynthesis. Many small transition metal complexes possess chemical coordination environments in the vicinity of the metal atom that are reminiscent of these active sites. We have studied the electronic structure of these molecules and discussed the relevance for their biological analogues. The specific question on which we wish to focus is: Do strong correlations (resulting from the localized character of the TM 3d-orbitals) contribute significantly to the reaction energetics of these molecules and, if so, can these effects be observed by experiment? To accomplish these ends we focus on the cobalt valence tautomer molecules and the phenomenon of electron transfer in aqueous hexaammine cobalt ions. We utilize theoretical methods in order to study the cobalt valence tautomer molecules which undergo an interconversion with temperature that is reminiscent of the changes in structure and spin that the heme group experiences as the result of Fe-ligand interactions. We perform fully ab initio calculations using the GGA implementation of density functional theory with the computer code SIESTA. In addition, a simple Anderson Impurity Model has been employed that more properly accounts for the Coulomb interaction among the 3d electrons on the cobalt atom. The calculated Co K x-ray absorption near-edge spectra XANES agrees well with experimental data and a prediction for the Co L-edge XAS that could be tested in future experiments is also presented. We believe that there are structures in both spectra that may only be explained by a strong admixture of configurations. It is conjectured that strong electron correlations help explain the non-Arrhenius rate behavior observed in the high-spin to low-spin relaxation rate at low temperatures. Work on electron-transfer in CoNH32 +/3+6aq using these
Statistics-based investigation on typhoon transition modeling
DEFF Research Database (Denmark)
Zhang, Shuoyun; Nishijima, Kazuyoshi
and the seasonality are taken into account by developing the models for different spatial grids and seasons separately. An appropriate size of spatial grids is investigated. The statistical characteristics of the random residual terms in the models are also examined. Finally, Monte Carlo simulations are performed......The present study revisits the statistical modeling of typhoon transition. The objective of the study is to provide insights on plausible statistical typhoon transition models based on extensive statistical analysis. First, the correlation structures of the typhoon transition are estimated in terms...
Yang-Mills correlators across the deconfinement phase transition
Reinosa, U; Tissier, M; Tresmontant, A
2016-01-01
We compute the finite temperature ghost and gluon propagators of Yang-Mills theory in the Landau-DeWitt gauge. The background field that enters the definition of the latter is intimately related with the (gauge-invariant) Polyakov loop and serves as an equivalent order parameter for the deconfinement transition. We use an effective gauge-fixed description where the nonperturbative infrared dynamics of the theory is parametrized by a gluon mass which, as argued elsewhere, may originate from the Gribov ambiguity. In this scheme, one can perform consistent perturbative calculations down to infrared momenta, which have been shown to correctly describe the phase diagram of Yang-Mills theories in four dimensions as well as the zero-temperature correlators computed in lattice simulations. In this article, we provide the one-loop expressions of the finite temperature Landau-DeWitt ghost and gluon propagators for a large class of gauge groups and present explicit results for the SU(2) case. These are substantially dif...
Feasibility of a metamagnetic transition in correlated systems
Acharya, Swagata; Medhi, Amal; Vidhyadhiraja, N. S.; Taraphder, A.
2016-03-01
The long-standing issue of the competition between the magnetic field and the Kondo effect, favoring, respectively, triplet and singlet ground states, is addressed using a cluster slave-rotor mean-field theory for the Hubbard model and its spin-correlated, spin-frustrated extensions in two dimensions. The metamagnetic jump is established and compared with earlier results of dynamical mean-field theory. This approach also reproduces the emergent super-exchange energy scale in the insulating side. A scaling is found for the critical Zeeman field in terms of the intrinsic coherence scale just below the metal-insulator transition, where the critical spin fluctuations are soft. The conditions required for metamagnetism to appear at a reasonable field are also underlined. Gutzwiller analysis on the two-dimensional Hubbard model and a quantum Monte Carlo calculation on the Heisenberg spin system are performed to check the limiting cases of the cluster slave-rotor results for the Hubbard model. Low-field scaling features for magnetization are discussed.
Semiconductor-to-metal transition in trans-polyacetylene (the role of correlated solitons
Directory of Open Access Journals (Sweden)
S. A. Ketabi
2004-06-01
Full Text Available In this study the nature of transition to metallic regime in trans-polyacetylene (trans-PA is investigated. Based on Su-Schrieffer-Heeger (SSH model and the use of Continued - Fraction Representation (CFR as well as Lanczos algorithm procedure, we studied the effects of some selected soliton distributions on the semiconductor-to-metal transition in trans-PA.We found that,this transition occurs only when there exists a soliton sublattice in trans-PA, disordered soliton distributions and soliton clustering are the origin of the metallic transition in trans-PA, that is consistent with the experimental data. Our results show that in the presence of correlation between solitons, the disorder in accompanying single soliton distributions plays a crucial role in inducing the transition to metallic regime, so that in contrast to Anderson’s localization theorem, the electronic states near the Fermi level are extended, that is the most significant criteria for the metallic regime .
The Berezinskii-Kosterlitz-Thouless transition and correlations in the XY kagome antiferromagnet
Cherepanov, V B; Podivilov, E V
2001-01-01
The problem of the Berezinskii-Kosterlitz-Thouless transition in the highly frustrated XY antiferromagnetic is solved. The transition temperature is found. It is shown that the spin correlation function exponentially decays with distance even in the low-temperature phase, in contrast to the order parameter correlation function, which decays algebraically with distance
Long Range Correlations and Phase Transitions in Non-equilibrium Diffusive Systems
Bodineau, T.; Derrida, B.; Lecomte, V.; van Wijland, F.
2008-12-01
We obtain explicit expressions for the long range correlations in the ABC model and in diffusive models conditioned to produce an atypical current of particles. In both cases, the two-point correlation functions allow one to detect the occurrence of a phase transition as they become singular when the system approaches the transition.
Retarded correlators in kinetic theory: branch cuts, poles and hydrodynamic onset transitions
Energy Technology Data Exchange (ETDEWEB)
Romatschke, Paul [University of Colorado, Department of Physics, Boulder, CO (United States); University of Colorado, Center for Theory of Quantum Matter, Boulder, CO (United States)
2016-06-15
In this work the collective modes of an effective kinetic theory description based on the Boltzmann equation in a relaxation-time approximation applicable to gauge theories at weak but finite coupling and low frequencies are studied. Real time retarded two-point correlators of the energy-momentum tensor and the R-charge current are calculated at finite temperature in flat space-times for large N gauge theories. It is found that the real-time correlators possess logarithmic branch cuts which in the limit of large coupling disappear and give rise to non-hydrodynamic poles that are reminiscent of quasi-normal modes in black holes. In addition to branch cuts, correlators can have simple hydrodynamic poles, generalizing the concept of hydrodynamic modes to intermediate wavelength. Surprisingly, the hydrodynamic poles cease to exist for some critical value of the wavelength and coupling reminiscent of the properties of onset transitions. (orig.)
Correlation functions between specific volume and stoichiometry for transition metal nitrides
Energy Technology Data Exchange (ETDEWEB)
Soto, G. [Centro de Ciencias de la Materia Condensada, UNAM, Ap. Postal 2681, 22800 Ensenada B. C. (Mexico)]. E-mail: gerardo@ccmc.unam.mx; Aparicio, E. [Centro de Ciencias de la Materia Condensada, UNAM, Ap. Postal 2681, 22800 Ensenada B. C. (Mexico); Avalos-Borja, M. [Centro de Ciencias de la Materia Condensada, UNAM, Ap. Postal 2681, 22800 Ensenada B. C. (Mexico)
2005-03-08
A methodology is proposed to correlate the structural aspects of transition metal nitrides (TMN) to the stoichiometric ratio: x = [N]/[M]. The method is based on a numeric figure, {upsilon}, given by the difference between the atomic concentrations of nitride and parent metal normalized to the atomic concentration of parent metal. Numerical regression is used to construct interpolating functions for {upsilon}(x) using as input the available data for TMN in two well-recognized databases (ICDD and ICSD). In summary we obtain functions of x that describe the deformation caused in the parent metal lattice by the nitrogen assimilation. The results are attractive, since TMN show remarkable trends.
A Correlation-Based Fingerprint Verification System
Bazen, Asker M.; Verwaaijen, Gerben T.B.; Gerez, Sabih H.; Veelenturf, Leo P.J.; Zwaag, van der Berend Jan
2000-01-01
In this paper, a correlation-based fingerprint verification system is presented. Unlike the traditional minutiae-based systems, this system directly uses the richer gray-scale information of the fingerprints. The correlation-based fingerprint verification system first selects appropriate templates i
Directory of Open Access Journals (Sweden)
Yang Zhijie
2016-01-01
Full Text Available Most existing project assessment relies on expert scoring, whose precision can be deteriorated by personal subjectivity. This paper presents an assessment method to compare the advantages and disadvantages of three cohesion patterns between suburban and urban rail transit network, which reduces the influence of subjective score. A modified rough set – grey correlation model is developed as a core of this assessment, based on the integration of rough set theory and grey correlational analysis, where an index system is set up for model calculation. A case study using the network in Ningbo is applied to demonstrate the effectiveness of the method, the results show that the method is more effective using discretely distributed data sensitive to sample size. The consistency of the results in comparison with marginal cost analysis can be a preliminary verification of the model.
DEFF Research Database (Denmark)
Silvennoinen, Annastiina; Teräsvirta, Timo
In this paper we propose a multivariate GARCH model with a time-varying conditional correlation structure. The new Double Smooth Transition Conditional Correlation GARCH model extends the Smooth Transition Conditional Correlation GARCH model of Silvennoinen and Ter¨asvirta (2005) by including...... another variable according to which the correlations change smoothly between states of constant correlations. A Lagrange multiplier test is derived to test the constancy of correlations against the DSTCC-GARCH model, and another one to test for another transition in the STCC-GARCH framework. In addition......, other specification tests, with the aim of aiding the model building procedure, are considered. Analytical expressions for the test statistics and the required derivatives are provided. The model is applied to a selection of world stock indices, and it is found that time is an important factor affecting...
Ring Counter Based ATPG for Low Transition Test Pattern Generation.
Begam, V M Thoulath; Baulkani, S
2015-01-01
In test mode test patterns are applied in random fashion to the circuit under circuit. This increases switching transition between the consecutive test patterns and thereby increases dynamic power dissipation. The proposed ring counter based ATPG reduces vertical switching transitions by inserting test vectors only between the less correlative test patterns. This paper presents the RC-ATPG with an external circuit. The external circuit consists of XOR gates, full adders, and multiplexers. First the total number of transitions between the consecutive test patterns is determined. If it is more, then the external circuit generates and inserts test vectors in between the two test patterns. Test vector insertion increases the correlation between the test patterns and reduces dynamic power dissipation. The results prove that the test patterns generated by the proposed ATPG have fewer transitions than the conventional ATPG. Experimental results based on ISCAS'85 and ISCAS'89 benchmark circuits show 38.5% reduction in the average power and 50% reduction in the peak power attained during testing with a small size decoding logic.
Energy Technology Data Exchange (ETDEWEB)
Ford, Eric B.; /Florida U.; Fabrycky, Daniel C.; /Lick Observ.; Steffen, Jason H.; /Fermilab; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Moorhead, Althea V.; /Florida U.; Morehead, Robert C.; /Florida U.; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Rowe, Jason F.; /NASA, Ames /SETI Inst., Mtn. View /San Diego State U., Astron. Dept.
2012-01-01
We present a new method for confirming transiting planets based on the combination of transit timing variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the transit timing variations of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:9 and 2:4:6:9 period commensurabilities. Our results demonstrate that TTVs provide a powerful tool for confirming transiting planets, including low-mass planets and planets around faint stars for which Doppler follow-up is not practical with existing facilities. Continued Kepler observations will dramatically improve the constraints on the planet masses and orbits and provide sensitivity for detecting additional non-transiting planets. If Kepler observations were extended to eight years, then a similar analysis could likely confirm systems with multiple closely spaced, small transiting planets in or near the habitable zone of solar-type stars.
METAL-INSULATOR TRANSITIONS AND STRONG ELECTRON CORRELATIONS
MICHIELSEN, K
1993-01-01
An overview of lattice models for strongly correlated electrons is given. A detailed study is presented of a model recently introduced by Montorsi and Rasetti. Analytical, exact diagonalization and Quantum Monte Carlo techniques are employed to investigate the static and dynamic properties of this m
Multiple cross-correlation noise induced transition in a stochastic bistable system
Wang, Can-Jun; Yang, Ke-Li; Du, Chun-Yan
2017-03-01
Based on the stochastic equivalent rules, the Fokker-Planck Equation for a general one-dimensional nonlinear system subjected to N-component noises and cross-correlation noises is derived, and the greatest advantage of the method lies in its simplicity. Applying this method, the effects of multiple sources of noise and the correlation forms of noises among them (i.e., two multiplicative noises, an additive noise and the correlation between the three noises) on the steady-state properties and the mean first passage time (MFPT) of a stochastic bistable system are discussed in details. The results show rich transition phenomena, such as the reentrance-like noise-induced phenomenon and the switch between the bimodal and the unimodal structure for different noise intensities. Moreover, the effects of the cross-correlation among the three noise sources on the MFPT are also discussed, and the noise-enhanced stability phenomenon and the resonant activation phenomenon are observed. The numerical results are in basic agreement with the theoretical predictions.
Chen, Wei; Legner, Markus; Rüegg, Andreas; Sigrist, Manfred
2017-02-01
The correlation functions related to topological phase transitions in inversion-symmetric lattice models described by 2 ×2 Dirac Hamiltonians are discussed. In one dimension, the correlation function measures the charge-polarization correlation between Wannier states at different positions, while in two dimensions it measures the itinerant-circulation correlation between Wannier states. The correlation function is nonzero in both the topologically trivial and nontrivial states, and allows us to extract a correlation length that diverges at topological phase transitions. The correlation length and the curvature function that defines the topological invariants are shown to have universal critical exponents, allowing the notion of universality classes to be introduced. Particularly in two dimensions, the universality class is determined by the orbital symmetry of the Dirac model. The scaling laws that constrain the critical exponents are revealed, and are predicted to be satisfied even in interacting systems, as demonstrated in an interacting topological Kondo insulator.
Bhowmik, Anal; Roy, Sourav; Majumder, Sonjoy
2016-01-01
This work presents precise calculations of important electromagnetic transition amplitudes along with detail of their many-body correlations using relativistic coupled cluster method. Studies of hyperfine interaction constants, useful for plasma diagnostic, with this correlation exhaustive many-body approach are another important area of this work. The calculated oscillator strengths of allowed transitions, amplitudes of forbidden transitions and lifetimes are compared with the other theoretical results wherever available and they show a good agreement. Hyperfine constants of ?different isotopes of W VI, presented in this paper will be helpful to get accurate picture of abundances of this element in different astronomical bodies.
Non-local Coulomb correlations in metals close to a charge order insulator transition
Merino, Jaime
2008-03-01
Recent extensions of dynamical mean-field theory (DMFT) to clusters either in its real space (CDMFT) or momentum space versions (DCA) have become important tools for the description of electronic properties of low dimensional strongly correlated systems. In contrast to single site DMFT, short range correlation effects on electronic properties of systems close to the Mott transition can be analyzed. We have investigated the charge ordering transition induced by the nearest-neighbor Coulomb repulsion V in the 1/4-filled extended Hubbard model using CDMFT. We find a transition to a strongly renormalized charge ordered Fermi liquid at VCO and a metal-to- insulator transition at VMI>VCO. Short range antiferromagnetism occurs concomitantly with the CO transition. Approaching the charge ordered insulator, V
Transition metal based borohydrides for hydrogen storage
Jayanthi, Chakram; Liu, Jianjun; Wei, Suhuai; Zhao, Yufeng
2010-03-01
Using ab-initio studies based on the density-functional theory, we have calculated binding energies per hydrogen molecule for decomposition reactions of transition metal borohydrides MHxB12H12 to MB12 structures, where M corresponds to Sc, Ti, or V. Depending on the valence of the transition metal, x can be 1, 2, or 3. Crystal structures considered for MB12 included both hypothetical and those found in the international crystallographic structural database. On the other hand, the crystal structure considered for MHxB12H12 belongs to C2/c (space group 15) structure as reported in a previous study [V. Ozolins et al. JACS, 131, 230 (2009)]. Among the structures investigated, Titanium-based metal borohydride structure has the lowest binding energy per hydrogen molecule relative to the cubic TiB12 structure (˜0.37 eV/H2). Our finding should be contrasted with the binding energy/H2 for simple metal based borohydrides (e.g., CaB12H12 ), which has a value of ˜ 1.5 eV/H2, suggesting that transition metals play a significant role in lowering the H2 binding energy in borohydrides.
Laser materials based on transition metal ions
Moncorgé, Richard
2017-01-01
The purpose of this presentation is to review the spectroscopic properties of the main laser materials based on transition metal ions which lead to noticeable laser performance at room temperature and, for very few cases, because of unique properties, when they are operated at cryogenic temperatures. The description also includes the materials which are currently being used as saturable absorbers for passive-Q-switching of a variety of other near- and mid-infrared solid state lasers. A substantial part of the article is devoted first to the description of the energy levels and of the absorption and emission transitions of the transition metal ions in various types of environments by using the well-known Tanabe-Sugano diagrams. It is shown in particular how these diagrams can be used along with other theoretical considerations to understand and describe the spectroscopic properties of ions sitting in crystal field environments of near-octahedral or near-tetrahedral symmetry. The second part is then dedicated to the description (positions and intensities) of the main absorption and emission features which characterize the different types of materials.
Electronic correlations at the alpha-gamma structural phase transition in paramagnetic iron
Leonov, I.; Poteryaev, A. I.; Anisimov, V. I.; Vollhardt, D.
2010-01-01
We compute the equilibrium crystal structure and phase stability of iron at the alpha(bcc)-gamma(fcc) phase transition as a function of temperature, by employing a combination of ab initio methods for calculating electronic band structures and dynamical mean-field theory. The magnetic correlation energy is found to be an essential driving force behind the alpha-gamma structural phase transition in paramagnetic iron.
Universal dynamics of density correlations at the transition to the many-body localized state
Mierzejewski, M.; Herbrych, J.; Prelovšek, P.
2016-12-01
Within one-dimensional disordered models of interacting fermions, we perform a numerical study of several dynamical density correlations, which can serve as hallmarks of the transition to the many-body localized state. The results confirm that density-wave correlations exhibit quite an abrupt change with increasing disorder, with a nonvanishing long-time value characteristic for the nonergodic phase. In addition, our results reveal a logarithmic variation of correlations in time in a wide time window, which we can bring in connection with the anomalous behavior of the dynamical conductivity near the transition. Our results support the view that the transition to many-body localization can be characterized by universal dynamical exponents.
Optical correlation recognition based on LCOS
Tang, Mingchuan; Wu, Jianhong
2013-08-01
Vander-Lugt correlator[1] plays an important role in optical pattern recognition due to the characteristics of accurate positioning and high signal-to-noise ratio. The ideal Vander-Lugt correlator should have the ability of outputting strong and sharp correlation peak in allusion to the true target, in the existing Spatial Light Modulators[2], Liquid Crystal On Silicon(LCOS) has been the most competitive candidate for the matched filter owing to the continuous phase modulation peculiarity. Allowing for the distortions of the target to be identified including rotations, scaling changes, perspective changes, which can severely impact the correlation recognition results, herein, we present a modified Vander-Lugt correlator based on the LCOS by means of applying an iterative algorithm to the design of the filter so that the correlator can invariant to the distortions while maintaining good performance. The results of numerical simulation demonstrate that the filter could get the similar recognition results for all the training images. And the experiment shows that the modified correlator achieves the 180° rotating tolerance significantly improving the recognition efficiency of the correlator.
E2 transitions between excited single-phonon states: Role of ground-state correlations
Energy Technology Data Exchange (ETDEWEB)
Kamerdzhiev, S. P. [National Research Centre Kurchatov Institute (Russian Federation); Voitenkov, D. A., E-mail: dvoytenkov@ippe.ru [Institute for Physics and Power Engineering (Russian Federation)
2016-11-15
The probabilities for E2 transitions between low-lying excited 3{sup −} and 5{sup −} single-phonon states in the {sup 208}Pb and {sup 132}Sn magic nuclei are estimated on the basis of the theory of finite Fermi systems. The approach used involves a new type of ground-state correlations, that which originates from integration of three (rather than two, as in the random-phase approximation) single-particle Green’s functions. These correlations are shown to make a significant contribution to the probabilities for the aforementioned transitions.
Asymmetric Watermarking Scheme Based on Correlation Testing
Directory of Open Access Journals (Sweden)
Rinaldi Munir
2007-06-01
Full Text Available Abstract Asymmetric watermarking is the second generation of watermarking scheme which uses different keys for embedding and detecting watermark. Key for embedding is private or secret, but key for detecting can be available publicly and everyone who has the key can detect watermark Watermark detection does not need to be original multimedia data. Detection of watermark is realized using correlation test between public key and multimedia data received. In most of schemes, private key is the watermark itself; public key is public watermark which correlates to the private watermark This paper presents concept of asymmetric watermarking scheme that based on correlation test and reviews some schemes of asymmetric watermarking that have been proposed by researchers. Keywords: asymmetric watermarking, private key, public key, watermark., multimeelia,:correlation.
Peng, Xianneng; Shao, Zhengzhong; Chen, Xin; Knight, David P; Wu, Peiyi; Vollrath, Fritz
2005-01-01
We used two-dimensional (2D) correlation infrared spectroscopy to study further the potassium-induced conformation transition in Nephila spidroin films. It provided increased resolution and important new information on the sequence of events in the conformation transition process, showing that beta-sheet formed from the helical component before they formed from random coil. It also showed more evidence that formation of the 1691 cm(-1) (turn/bend) peak did not proceed with the same kinetics as the 1620 cm(-1) (antiparallel beta-sheet component) one, so we attribute the 1691 cm(-1) peak to turns which formed with different kinetics as the antiparallel beta-sheets. We present a single coherent and detailed hypothesis for the assembly and secondary structural transition of silk proteins in vivo and in vitro based on our findings and on evidence from other laboratories.
Renyi Correlations and Phase Transitions in the Transverse-Field Ising model
Singh, Rajiv; Devakul, Trithep
2015-03-01
We calculate T = 0 spin-spin correlation functions with respect to a probability distribution given by an integer power (n) of the reduced density matrix ρcirc;A, when a transverse-field Ising model (TFIM) system is bipartitioned by a planar interface. Using series expansion methods these calculations are done in the thermodynamic limit for arbitrary positive integer n, with n = 1 giving us the bulk correlations. We study the TFIM system on isotropic and anisotropic simple-cubic lattices. We examine the evidence for whether the critical point of the transition deviates from the bulk critical point as a function of n and whether the critical behavior lies in the 2 D or 4 D Ising universality classes as would be expected from a surface transition at finite temperature and a T = 0 bulk transition, respectively. Work supported in part by NSF Grant Number DMR-1306048.
Insulator to correlated metal transition in V_1-xMo_xO_2
Energy Technology Data Exchange (ETDEWEB)
Klimczuk, Tomasz [Los Alamos National Laboratory; Ronning, Filip [Los Alamos National Laboratory; Holman, Katherine [PRINCETON UNIV; Mcqueen, Tyrel M [PRINCETON UNIV; Williams, Anthony J [PRINDCETON UNIV; Stephens, P W [BNL; Zandbergen, Henny W [DELFT INSTIT OF TECH; Xu, Q [DELFT INSTIT OF TECH; Cava, Robert J [PRINCETON UNIV
2009-01-01
The change from metallic to insulating states is one of the most dramatic transitions that solids undergo on cooling or chemical doping. Many materials display this transition, but only a handful have the right combination of crystal structure and physical properties to serve as model systems. VO{sub 2} is one of those materials. Using Mo as a chemical dopant in VO{sub 2}, we find unanticipated phenomenology for both the electronic and structural characteristics of the resulting insulator to metal transition. The results support a complex, previously proposed scenario involving the coexistence of both electron repulsion and electron pairing for yielding an insulator in VO{sub 2}, but not simply; many issues are raised about local versus itinerant behavior and structure-property correlations in this most iconic ofdoped correlated electron systems.
Humphries, T D; Sheppard, D A; Buckley, C E
2015-06-30
For homoleptic 18-electron complex hydrides, an inverse linear correlation has been established between the T-deuterium bond length (T = Fe, Co, Ni) and the average electronegativity of the metal countercations. This relationship can be further employed towards aiding structural solutions and predicting physical properties of novel complex transition metal hydrides.
Yu, Haoyu S; Zhang, Wenjing; Verma, Pragya; He, Xiao; Truhlar, Donald G
2015-05-14
The goal of this work is to develop a gradient approximation to the exchange-correlation functional of Kohn-Sham density functional theory for treating molecular problems with a special emphasis on the prediction of quantities important for homogeneous catalysis and other molecular energetics. Our training and validation of exchange-correlation functionals is organized in terms of databases and subdatabases. The key properties required for homogeneous catalysis are main group bond energies (database MGBE137), transition metal bond energies (database TMBE32), reaction barrier heights (database BH76), and molecular structures (database MS10). We also consider 26 other databases, most of which are subdatabases of a newly extended broad database called Database 2015, which is presented in the present article and in its ESI. Based on the mathematical form of a nonseparable gradient approximation (NGA), as first employed in the N12 functional, we design a new functional by using Database 2015 and by adding smoothness constraints to the optimization of the functional. The resulting functional is called the gradient approximation for molecules, or GAM. The GAM functional gives better results for MGBE137, TMBE32, and BH76 than any available generalized gradient approximation (GGA) or than N12. The GAM functional also gives reasonable results for MS10 with an MUE of 0.018 Å. The GAM functional provides good results both within the training sets and outside the training sets. The convergence tests and the smooth curves of exchange-correlation enhancement factor as a function of the reduced density gradient show that the GAM functional is a smooth functional that should not lead to extra expense or instability in optimizations. NGAs, like GGAs, have the advantage over meta-GGAs and hybrid GGAs of respectively smaller grid-size requirements for integrations and lower costs for extended systems. These computational advantages combined with the relatively high accuracy for all
Initiation of sleep-dependent cortical-hippocampal correlations at wakefulness-sleep transition.
Haggerty, Daniel C; Ji, Daoyun
2014-10-01
Sleep is involved in memory consolidation. Current theories propose that sleep-dependent memory consolidation requires active communication between the hippocampus and neocortex. Indeed, it is known that neuronal activities in the hippocampus and various neocortical areas are correlated during slow-wave sleep. However, transitioning from wakefulness to slow-wave sleep is a gradual process. How the hippocampal-cortical correlation is established during the wakefulness-sleep transition is unknown. By examining local field potentials and multiunit activities in the rat hippocampus and visual cortex, we show that the wakefulness-sleep transition is characterized by sharp-wave ripple events in the hippocampus and high-voltage spike-wave events in the cortex, both of which are accompanied by highly synchronized multiunit activities in the corresponding area. Hippocampal ripple events occur earlier than the cortical high-voltage spike-wave events, and hippocampal ripple incidence is attenuated by the onset of cortical high-voltage spike waves. This attenuation leads to a temporary weak correlation in the hippocampal-cortical multiunit activities, which eventually evolves to a strong correlation as the brain enters slow-wave sleep. The results suggest that the hippocampal-cortical correlation is established through a concerted, two-step state change that first synchronizes the neuronal firing within each brain area and then couples the synchronized activities between the two regions.
Directory of Open Access Journals (Sweden)
Takahiko Sasaki
2012-05-01
Full Text Available The Mott-Anderson transition has been known as a metal-insulator (MI transition due to both strong electron-electron interaction and randomness of the electrons. For example, the MI transition in doped semiconductors and transition metal oxides has been investigated up to now as a typical example of the Mott-Anderson transition for changing electron correlations by carrier number control in concurrence with inevitable randomness. On the other hand, molecular conductors have been known as typical strongly correlated electron systems with bandwidth controlled Mott transition. In this paper, we demonstrate our recent studies on the randomness effect of the strongly correlated electrons of the BEDT-TTF molecule based organic conductors. X-ray irradiation on the crystals introduces molecular defects in the insulating anion layer, which cause random potential modulation of the correlated electrons in the conductive BEDT-TTF layer. In combination with hydrostatic pressure, we are able to control the parameters for randomness and correlations for electrons approaching the Mott-Anderson transition.
Monotonic quantum-to-classical transition enabled by positively correlated biphotons
Jin, Rui-Bo; Chen, Guo-Qun; Jing, Hui; Ren, Changliang; Zhao, Pei; Shimizu, Ryosuke; Lu, Pei-Xiang
2017-06-01
Multiparticle interference is a fundamental phenomenon in the study of quantum mechanics. It was discovered in a recent experiment [Y.-S. Ra et al., Proc. Natl. Acad. Sci. USA 110, 1227 (2013), 10.1073/pnas.1206910110] that spectrally uncorrelated biphotons exhibited a nonmonotonic quantum-to-classical transition in a four-photon Hong-Ou-Mandel (HOM) interference. In this work, we consider the same scheme with spectrally correlated photons. By theoretical calculation and numerical simulation, we found the transition not only can be nonmonotonic with negatively correlated or uncorrelated biphotons, but also can be monotonic with positively correlated biphotons. The fundamental reason for this difference is that the HOM-type multiphoton interference is a differential-frequency interference. Our study may shed new light on understanding the role of frequency entanglement in multiphoton behavior.
Ding, Xiaobin; Sun, Rui; Koike, Fumihiro; Kato, Daiji; Murakami, Izumi; Sakaue, Hiroyuki A.; Dong, Chenzhong
2017-03-01
The electron correlation effects and Breit interaction as well as Quantum Electro-Dynamics (QED) effects were expected to have important contribution to the energy level and transition properties of heavy highly charged ions. The ground states [Ne]3 s 23 p 63 d 2 and first excited states [Ne]3 s 23 p 53 d 3 of W54+ ion have been studied by using Multi-Configuration Dirac-Fock method with the implementation of Grasp2K package. A restricted active space method was employed to investigate the correlation contribution from different models. The Breit interaction and QED effects were taken into account in the relativistic configuration interaction calculation with the converged wavefunction. It is found that the correlation contribution from 3 s and 3 p orbital have important contribution to the energy level, transition wavelength and probability of the ground and the first excited state of W54+ ion.
Chu, Daoliang; Yu, Jianxin; Tong, Jinnan; Benton, Michael J.; Song, Haijun; Huang, Yunfei; Song, Ting; Tian, Li
2016-11-01
The Permian-Triassic boundary marks the greatest mass extinction during the Phanerozoic, which was coupled with major global environmental changes, and is known especially from well-preserved marine fossil records and continuous carbonate deposits. However, the placement of the Permian-Triassic boundary in terrestrial sections and accurate correlation with the marine strata are difficult due to the absence of the key marine index fossils in terrestrial-marine siliciclastic settings. Here, we present detailed fossil data from four terrestrial sections, two paralic sections and one shallow marine section in South China. Our data show that the rapid mass disappearance of the Gigantopteris flora in various sections represents the end-Permian mass extinction and the base of the Permian-Triassic transitional beds in terrestrial-marine siliciclastic settings of South China. In particular, we find a mixed marine and terrestrial biota from the coastal transitional sections of the Permian-Triassic transitional Kayitou Formation, which provides a unique intermediate link for biostratigraphic correlation between terrestrial and marine sequences. Accordingly, the Euestheria gutta-bearing conchostracan fauna and the Pteria ussurica variabilis-Towapteria scythica-Eumorphotis venetiana bivalve assemblage are proposed as markers of the Permian-Triassic transitional beds in terrestrial-marine siliciclastic settings of South China.
He, Yuan-Yao; Wu, Han-Qing; You, Yi-Zhuang; Xu, Cenke; Meng, Zi Yang; Lu, Zhong-Yi
2016-03-01
It is expected that the interplay between nontrivial band topology and strong electron correlation will lead to very rich physics. Thus a controlled study of the competition between topology and correlation is of great interest. Here, employing large-scale quantum Monte Carlo simulations, we provide a concrete example of the Kane-Mele-Hubbard model on an AA-stacking bilayer honeycomb lattice with interlayer antiferromagnetic interaction. Our simulation identified several different phases: a quantum spin Hall insulator (QSH), an x y -plane antiferromagnetic Mott insulator, and an interlayer dimer-singlet insulator. Most importantly, a bona fide topological phase transition between the QSH and the dimer-singlet insulators, purely driven by the interlayer antiferromagnetic interaction, is found. At the transition, the spin and charge gap of the system close while the single-particle excitations remain gapped, which means that this transition has no mean-field analog and it can be viewed as a transition between bosonic symmetry-protected topological (SPT) states. At one special point, this transition is described by a (2 +1 )d O (4 ) nonlinear sigma model with exact S O (4 ) symmetry and a topological term at exactly Θ =π . The relevance of this work towards more general interacting SPT states is discussed.
Bona fide interaction-driven topological phase transition in correlated SPT states
Meng, Zi Yang; He, Yuan-Yao; Wu, Han-Qing; You, Yi-Zhuang; Xu, Cenke; Lu, Zhong-Yi
It is expected the interplay between non-trivial band topology and strong electron correlation will lead to very rich physics. Thus a controlled study of the competition between topology and correlation is of great interest. Here, employing large-scale quantum Monte Carlo simulations, we provide a concrete example of the Kane-Mele-Hubbard model on an AA stacking bilayer honeycomb lattice with inter-layer antiferromagnetic interaction. Our simulation identified several different phases: a quantum spin-Hall insulator (QSH), a xy-plane antiferromagnetic Mott insulator (xy-AFM) and an inter-layer dimer-singlet insulator (dimer-singlet). Most importantly, a bona fide topological phase transition between the QSH and the dimer-singlet insulators, purely driven by the inter-layer antiferromagnetic interaction is found. At the transition, the spin and charge gap of the system close while the single-particle excitations remain gapped, which means that this transition has no mean field analogue and it can be viewed as a transition between bosonic SPT states. At one special point, this transition is described by a (2+1)d O(4) nonlinear sigma model with exact SO(4) symmetry, and a topological term at theta=p. Relevance of this work towards more general interacting SPT states is discussed.
Hyska, Jolanda; Mersini, Ehadu; Mone, Iris; Burazeri, Genc
2014-10-01
Our aim was to assess the prevalence and demographic correlates of overweight and obesity among children in Albania, a transitional country in Southeastern Europe. A nationwide survey was conducted in Albania in 2013 including a representative sample of 5,810 schoolchildren aged 7.0-9.9 years (51.5 % boys aged 8.5 ± 0.6 years and 49.5 % girls aged 8.4 ± 0.6 years; overall response: 97 %). All children were measured height and weight, based on which the body mass index (BMI) was calculated. The criteria of the World Health Organization (WHO) and the International Obesity Task Force (IOTF) were used to describe the distribution of BMI among children. Overall, mean value of BMI was 16.4 ± 2.4 (16.7 ± 2.5 in boys vs. 16.2 ± 2.4 in girls, P < 0.001). As per WHO criteria, 9.8 % of the boys were obese versus 5.5 % of the girls (P < 0.001). The prevalence of both overweight and obesity were remarkably higher among urban children compared with their rural counterparts (17.9 vs. 10.5 and 11.9 vs. 4.0 %, respectively, P < 0.001). As per IOTF criteria, 3.8 % of the boys were obese compared with 2.8 % of the girls (P < 0.001). The prevalence of overweight and obesity were similarly higher among urban children than in rural children (15.6 vs. 7.3 and 5.5 vs. 1.4 %, respectively, P < 0.001). Our findings indicate that Albania is in the middle of nutritional transition with a high prevalence of overweight and obesity among children aged 7.0-9.9 years. This is particularly evident in urban areas of the country. Conversely, our data do not indicate a double burden of malnutrition among children in Albania.
Pressure induced phase transition behaviour in -electron based dialuminides
Indian Academy of Sciences (India)
P Ch Sahu; N V Chandra Shekar
2000-05-01
The rare-earth and actinide based compounds are endowed with several exotic physical and chemical properties due to the presence of -electrons. These properties exhibit interesting changes under the action of various thermodynamic ﬁelds and hence continues to be a subject of extensive research. For instance, under pressure, the nature of -electrons can be changed from localized to itinerant, leading to a variety of changes in their structural, physical and chemical properties. The present review on the high pressure phase transition behaviour of dialuminides of rare earths and actinides is an outcome of research in our laboratory during the last ﬁve years using a unique combination of a Guinier diffractometer and a diamond anvil cell built in-house. To bring out the correlations between the compressibility and structural behaviour with the electronic structure, we have also carried out electronic structure calculation. Further, the usefulness of Villars' three parameter structure maps in predicting pressure induced structural transitions has been explored and this has been illustrated with the available phase transition data.
Invariant correlational entropy as a signature of quantum phase transitions in nuclei
Energy Technology Data Exchange (ETDEWEB)
Volya, Alexander; Zelevinsky, Vladimir
2003-11-06
We study phase transformations in finite nuclei as a function of interaction parameters. The signature of a transition is given by invariant correlational entropy that reflects the sensitivity of an individual many-body state to changes of external parameters; peaks in this quantity indicate the critical regions. This approach is able to reveal the pairing phase transition, identify the isovector and isoscalar pairing regions and determine the role of other interactions. We show the examples of the phase diagram in the parameter space.
Liu, Kexi; Lei, Yinkai; Wang, Guofeng
2013-11-28
Oxygen adsorption energy is directly relevant to the catalytic activity of electrocatalysts for oxygen reduction reaction (ORR). In this study, we established the correlation between the O2 adsorption energy and the electronic structure of transition metal macrocyclic complexes which exhibit activity for ORR. To this end, we have predicted the molecular and electronic structures of a series of transition metal macrocyclic complexes with planar N4 chelation, as well as the molecular and electronic structures for the O2 adsorption on these macrocyclic molecules, using the density functional theory calculation method. We found that the calculated adsorption energy of O2 on the transition metal macrocyclic complexes was linearly related to the average position (relative to the lowest unoccupied molecular orbital of the macrocyclic complexes) of the non-bonding d orbitals (d(z(2)), d(xy), d(xz), and d(yz)) which belong to the central transition metal atom. Importantly, our results suggest that varying the energy level of the non-bonding d orbitals through changing the central transition metal atom and/or peripheral ligand groups could be an effective way to tuning their O2 adsorption energy for enhancing the ORR activity of transition metal macrocyclic complex catalysts.
Gait Correlation Analysis Based Human Identification
Directory of Open Access Journals (Sweden)
Jinyan Chen
2014-01-01
Full Text Available Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x, vertical axis (y, and temporal axis (t. By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features’ dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance.
Spectral methods and cluster structure in correlation-based networks
Heimo, Tapio; Tibély, Gergely; Saramäki, Jari; Kaski, Kimmo; Kertész, János
2008-10-01
We investigate how in complex systems the eigenpairs of the matrices derived from the correlations of multichannel observations reflect the cluster structure of the underlying networks. For this we use daily return data from the NYSE and focus specifically on the spectral properties of weight W=|-δ and diffusion matrices D=W/sj-δ, where C is the correlation matrix and si=∑jW the strength of node j. The eigenvalues (and corresponding eigenvectors) of the weight matrix are ranked in descending order. As in the earlier observations, the first eigenvector stands for a measure of the market correlations. Its components are, to first approximation, equal to the strengths of the nodes and there is a second order, roughly linear, correction. The high ranking eigenvectors, excluding the highest ranking one, are usually assigned to market sectors and industrial branches. Our study shows that both for weight and diffusion matrices the eigenpair analysis is not capable of easily deducing the cluster structure of the network without a priori knowledge. In addition we have studied the clustering of stocks using the asset graph approach with and without spectrum based noise filtering. It turns out that asset graphs are quite insensitive to noise and there is no sharp percolation transition as a function of the ratio of bonds included, thus no natural threshold value for that ratio seems to exist. We suggest that these observations can be of use for other correlation based networks as well.
Transit-Based Emergency Evacuation with Transit Signal Priority in Sudden-Onset Disaster
Directory of Open Access Journals (Sweden)
Ciyun Lin
2016-01-01
Full Text Available This study presents methods of transit signal priority without transit-only lanes for a transit-based emergency evacuation in a sudden-onset disaster. Arterial priority signal coordination is optimized when a traffic signal control system provides priority signals for transit vehicles along an evacuation route. Transit signal priority is determined by “transit vehicle arrival time estimation,” “queuing vehicle dissipation time estimation,” “traffic signal status estimation,” “transit signal optimization,” and “arterial traffic signal coordination for transit vehicle in evacuation route.” It takes advantage of the large capacities of transit vehicles, reduces the evacuation time, and evacuates as many evacuees as possible. The proposed methods were tested on a simulation platform with Paramics V6.0. To evaluate and compare the performance of transit signal priority, three scenarios were simulated in the simulator. The results indicate that the methods of this study can reduce the travel times of transit vehicles along an evacuation route by 13% and 10%, improve the standard deviation of travel time by 16% and 46%, and decrease the average person delay at a signalized intersection by 22% and 17% when the traffic flow saturation along an evacuation route is 0.81.0, respectively.
Correlation effects in (111) bilayers of perovskite transition-metal oxides
Energy Technology Data Exchange (ETDEWEB)
Okamoto, Satoshi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhu, Wenguang [Univ. of Science and Technology of China, Hefei (China); Nomura, Yusuke [Univ. of Tokyo (Japan); Arita, R. [Univ. of Tokyo (Japan); Xiao, Di [Carnegie Mellon Univ., Pittsburgh, PA (United States); Nagaosa, Naoto [Univ. of Tokyo (Japan); RIKEN Center for Emergent Matter Science (CEMS), Saitama (Japan)
2014-05-15
We investigate the correlation-induced Mott, magnetic, and topological phase transitions in artificial (111) bilayers of perovskite transition-metal oxides LaAuO_{3} and SrIrO_{3} for which the previous density-functional theory calculations predicted topological insulating states. Using the dynamical-mean-field theory with realistic band structures and Coulomb interactions, LaAuO_{3} bilayer is shown to be far away from a Mott insulating regime, and a topological-insulating state is robust. On the other hand, SrIrO_{3} bilayer is on the verge of an orbital-selective topological Mott transition and turns to a trivial insulator by an antiferromagnetic ordering. Oxide bilayers thus provide a novel class of topological materials for which the interplay between the spin-orbit coupling and electron-electron interactions is a fundamental ingredient.
Directory of Open Access Journals (Sweden)
P. A. Bhobe
2015-10-01
Full Text Available Transition metal compounds often undergo spin-charge-orbital ordering due to strong electron-electron correlations. In contrast, low-dimensional materials can exhibit a Peierls transition arising from low-energy electron-phonon-coupling-induced structural instabilities. We study the electronic structure of the tunnel framework compound K_{2}Cr_{8}O_{16}, which exhibits a temperature-dependent (T-dependent paramagnetic-to-ferromagnetic-metal transition at T_{C}=180 K and transforms into a ferromagnetic insulator below T_{MI}=95 K. We observe clear T-dependent dynamic valence (charge fluctuations from above T_{C} to T_{MI}, which effectively get pinned to an average nominal valence of Cr^{+3.75} (Cr^{4+}∶Cr^{3+} states in a 3∶1 ratio in the ferromagnetic-insulating phase. High-resolution laser photoemission shows a T-dependent BCS-type energy gap, with 2G(0∼3.5(k_{B}T_{MI}∼35 meV. First-principles band-structure calculations, using the experimentally estimated on-site Coulomb energy of U∼4 eV, establish the necessity of strong correlations and finite structural distortions for driving the metal-insulator transition. In spite of the strong correlations, the nonintegral occupancy (2.25 d-electrons/Cr and the half-metallic ferromagnetism in the t_{2g} up-spin band favor a low-energy Peierls metal-insulator transition.
Directory of Open Access Journals (Sweden)
A. Malhotra
2015-01-01
Full Text Available Peatlands in discontinuous permafrost regions occur as a mosaic of wetland types, each with variable sensitivity to climate change. Permafrost thaw further increases the spatial heterogeneity in ecosystem structure and function in peatlands. Carbon (C fluxes are well characterized in end-member thaw stages such as fully intact or fully thawed permafrost but remain unconstrained for transitional stages that cover a significant area of thawing peatlands. Furthermore, changes in the environmental correlates of C fluxes, due to thaw are not well described: a requirement for modeling future changes to C storage of permafrost peatlands. We investigated C fluxes and their correlates in end-member and a number of transitional thaw stages in a sub-arctic peatland. Across peatland lumped CH4 and CO2 flux data had significant correlations with expected correlates such as water table depth, thaw depth, temperature, photosynthetically active radiation and vascular green area. Within individual thaw states, bivariate correlations as well as multiple regressions between C flux and environmental factors changed variably with increasing thaw. The variability in directions and magnitudes of correlates reflects the range of structural conditions that could be present along a thaw gradient. These structural changes correspond to changes in C flux controls, such as temperature and moisture, and their interactions. Temperature sensitivity of CH4 increased with increasing thaw in bivariate analyses, but lack of this trend in multiple regression analyses suggested cofounding effects of substrate or water limitation on the apparent temperature sensitivity. Our results emphasize the importance of incorporating transitional stages of thaw in landscape level C budgets and highlight that end-member or adjacent thaw stages do not adequately describe the variability in structure-function relationships present along a thaw gradient.
Spatial correlations, clustering and percolation-like transitions in homicide crimes
Alves, L G A; Mendes, R S; Ribeiro, H V
2015-01-01
The spatial dynamics of criminal activities has been recently studied through statistical physics methods; however, models and results have been focused on local scales (city level) and much less is known about these patterns at larger scales such as at a country level. Here we report on a characterization of the spatial dynamics of the homicide crimes along the Brazilian territory using data from all cities (~5000) in a period of more than thirty years. Our results show that the spatial correlation function in the per capita homicides decays exponentially with the distance between cities and that the characteristic correlation length displays an acute increasing trend in the latest years. We also investigate the formation of spatial clusters of cities via a percolation-like analysis, where clustering of cities and a phase transition-like behavior describing the size of the largest cluster as a function of a homicide threshold are observed. This transition-like behavior presents evolutive features characteriz...
Anomalous long-range correlations at a non-equilibrium phase transition
Gerschenfeld, A.; Derrida, B.
2012-02-01
Non-equilibrium diffusive systems are known to exhibit long-range correlations, which decay like the inverse 1/L of the system size L in one dimension. Here, taking the example of the ABC model, we show that this size dependence becomes anomalous (the decay becomes a non-integer power of L) when the diffusive system approaches a second-order phase transition. This power-law decay as well as the L-dependence of the time-time correlations can be understood in terms of the dynamics of the amplitude of the first Fourier mode of the particle densities. This amplitude evolves according to a Langevin equation in a quartic potential, which was introduced in a previous work to explain the anomalous behavior of the cumulants of the current near this second-order phase transition. Here we also compute some of these cumulants away from the transition and show that they become singular as the transition is approached, matching with what we already knew in the critical regime.
Vadivasova, Tatiana E.; Strelkova, Galina I.; Bogomolov, Sergey A.; Anishchenko, Vadim S.
2016-09-01
We present numerical results for a set of bifurcations occurring at the transition from complete chaotic synchronization to spatio-temporal chaos in a ring of nonlocally coupled chaotic logistic maps. The regularities are established for the evolution of cross-correlations of oscillations in the network elements at the bifurcations related to the coupling strength variation. We reveal the distinctive features of cross-correlations for phase and amplitude chimera states. It is also shown that the effect of time intermittency between the amplitude and phase chimeras can be realized in the considered ensemble.
The Dynamics of Nonequilibrium Transitions Induced By the Cross-Correlated Noises: Numerical Results
Directory of Open Access Journals (Sweden)
A.N. Vitrenko
2010-01-01
Full Text Available The dynamic system described by the Langevin equation with two cross-correlated Gaussian white noises is considered. The non-equilibrium probability distribution function of the system is calculated by the numerical methods. The time of change of the initially unimodal distribution to the bimodal one is determined for different values of the control parameter. A critical slowing down in the transition dynamics is demonstrated.
Kim, Mock Ryeon; Park, Hye Won; Son, Jae Sung; Lee, Ran
2016-01-01
Purpose To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. Methods Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis. Results The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was 0.68±0.18 g/kg/d; according to age, the dose was 0.73±0.16 g/kg/d (<8 years), 0.53±0.12 g/kg/d (8 to <12 years), and 0.36±0.05 g/kg/d (12 to 15 years). The dose of lactulose was 1.99±0.43 mL/kg/d (<8 years) or 1.26±0.25 mL/kg/d (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268, p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267, p=0.022). Conclusion CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.
Directory of Open Access Journals (Sweden)
MR Jallali Nadoushan
2007-08-01
Full Text Available Background: The present study was undertaken to investigate the correlation of Epidermal Growth Factor Receptor (EGFR expression with grade of Transitional Cell Carcinoma (TCC. Methods: Tumor samples of 75 patients from Mostafa Khomaini Hospital with Transitional Cell Carcinoma of the bladder were analyzed by immunohistochemistry for expression of EGFR. In this context, we assigned the bladder tumors a grade accord¬ing WHO classification. Results analyzed for possible correlation with the expression status of the Epidermal Growth Factor Receptor (EGFR. Results: This cross-sectional study showed that all grades of Transitional Cell Carcinoma expressed EGFR, and 14 cases were LMP (18.9% which 10 cases among them had negative cells according EGFR point of view(71.4% and 4 cases had re¬ported positive (28.6%. Thirty five cases were low grade (46.7% which 18 cases among them had reported negative cells (51.4% and 17 cases had positive cells (48.6%. Twenty six cases were high grade (34.7% that 9 cases among them had reported negative cells (34.6%. Seventeen cases had positive cells (65.4%. Mann-Witney test showed relation between grade and expression of EGFR (P<0.05. Conclusions: This study showed that expression of EGFR is correlated with grade of tumor.
Directory of Open Access Journals (Sweden)
Randhir Singh
2015-03-01
Full Text Available Aim: The aim was to study the effect of the transition to body condition score (BCS and ultrasonographic back fat thickness (USG BFT in crossbred cows. Materials and Methods: A total of 101 multiparous crossbred cows in advanced pregnancy from organized dairy farm were taken up for study. The cows were grouped according to transition stage, i.e. far off dry (FOD, close up dry (CUD and fresh (F. BCS was estimated by using the five point visual BCS technique with 0.5 increments. The USG BFT was measured by real-time ultrasound using a portable Sonosite instrument. Results: In cows with BCS 2-2.5, the BFT of F period was significantly lower than FOD period. In cows with BCS 3-3.5, the mean BFT at F period was significantly reduced as compared to FOD and CUD period. The overall correlation coefficient between BCS and BFT for different transition stages was 84%, 79% and 75% for FOD, CUD and F period, respectively. Conclusion: The USG BFT gives an accurate measure of fat reserves in cows. The cows with BCS of ≥3.5 entering the transition period are more prone to lose body condition and hence require better and robust management during the transition period.
Electronic origin of structural transition in 122 Fe based superconductors
Ghosh, Haranath; Sen, Smritijit; Ghosh, Abyay
2017-03-01
Direct quantitative correlations between the orbital order and orthorhombicity is achieved in a number of Fe-based superconductors of 122 family. The former (orbital order) is calculated from first principles simulations using experimentally determined doping and temperature dependent structural parameters while the latter (the orthorhombicity) is taken from already established experimental studies; when normalized, both the above quantities quantitatively corresponds to each other in terms of their doping as well as temperature variations. This proves that the structural transition in Fe-based materials is electronic in nature due to orbital ordering. An universal correlations among various structural parameters and electronic structure are also obtained. Most remarkable among them is the mapping of two Fe-Fe distances in the low temperature orthorhombic phase, with the band energies Edxz, Edyz of Fe at the high symmetry points of the Brillouin zone. The fractional co-ordinate zAs of As which essentially determines anion height is inversely (directly) proportional to Fe-As bond distances (with exceptions of K doped BaFe2As2) for hole (electron) doped materials as a function of doping. On the other hand, Fe-As bond-distance is found to be inversely (directly) proportional to the density of states at the Fermi level for hole (electron) doped systems. Implications of these results to current issues of Fe based superconductivity are discussed.
Phase Correlation Based Iris Image Registration Model
Institute of Scientific and Technical Information of China (English)
Jun-Zhou Huang; Tie-Niu Tan; Li Ma; Yun-Hong Wang
2005-01-01
Iris recognition is one of the most reliable personal identification methods. In iris recognition systems, image registration is an important component. Accurately registering iris images leads to higher recognition rate for an iris recognition system. This paper proposes a phase correlation based method for iris image registration with sub-pixel accuracy.Compared with existing methods, it is insensitive to image intensity and can compensate to a certain extent the non-linear iris deformation caused by pupil movement. Experimental results show that the proposed algorithm has an encouraging performance.
Theoretical NMR correlations based Structure Discussion
Directory of Open Access Journals (Sweden)
Junker Jochen
2011-07-01
Full Text Available Abstract The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The actual difficulty of the structure elucidation problem depends more on the type of the investigated molecule than on its size. The moment HMBC data is involved in the process or a large number of heteroatoms is present, a possibility of multiple solutions fitting the same data set exists. A structure elucidation software can be used to find such alternative constitutional assignments and help in the discussion in order to find the correct solution. But this is rarely done. This article describes the use of theoretical NMR correlation data in the structure elucidation process with WEBCOCON, not for the initial constitutional assignments, but to define how well a suggested molecule could have been described by NMR correlation data. The results of this analysis can be used to decide on further steps needed to assure the correctness of the structural assignment. As first step the analysis of the deviation of carbon chemical shifts is performed, comparing chemical shifts predicted for each possible solution with the experimental data. The application of this technique to three well known compounds is shown. Using NMR correlation data alone for the description of the constitutions is not always enough, even when including 13C chemical shift prediction.
Safety models incorporating graph theory based transit indicators.
Quintero, Liliana; Sayed, Tarek; Wahba, Mohamed M
2013-01-01
There is a considerable need for tools to enable the evaluation of the safety of transit networks at the planning stage. One interesting approach for the planning of public transportation systems is the study of networks. Network techniques involve the analysis of systems by viewing them as a graph composed of a set of vertices (nodes) and edges (links). Once the transport system is visualized as a graph, various network properties can be evaluated based on the relationships between the network elements. Several indicators can be calculated including connectivity, coverage, directness and complexity, among others. The main objective of this study is to investigate the relationship between network-based transit indicators and safety. The study develops macro-level collision prediction models that explicitly incorporate transit physical and operational elements and transit network indicators as explanatory variables. Several macro-level (zonal) collision prediction models were developed using a generalized linear regression technique, assuming a negative binomial error structure. The models were grouped into four main themes: transit infrastructure, transit network topology, transit route design, and transit performance and operations. The safety models showed that collisions were significantly associated with transit network properties such as: connectivity, coverage, overlapping degree and the Local Index of Transit Availability. As well, the models showed a significant relationship between collisions and some transit physical and operational attributes such as the number of routes, frequency of routes, bus density, length of bus and 3+ priority lanes.
Introducing Opportunity-based Entrepreneurship in a Transition Economy
DEFF Research Database (Denmark)
Perunovic, Zoran
2005-01-01
This paper confronts necessity-based and opportunity-based entrepreneurial concepts in the transition of developing economies. The author constructs a research model and conducts field research (using Serbia as a case study) to explore how different personal and regional characteristics can favour......-up strategy for transition and developing economies....
Cieplicka-Oryńczak, N.; Szpak, B.; Leoni, S.; Fornal, B.; Bazzacco, D.; Blanc, A.; Bocchi, G.; Bottoni, S.; de France, G.; Jentschel, M.; Köster, U.; Mutti, P.; Simpson, G.; Soldner, T.; Ur, C.; Urban, W.
2016-07-01
The multipolarity of the main transition leading to the ground state in 210Bi was investigated using the angular correlations of γ rays. The analyzed γ -coincidence data were obtained from the 209Bi(n ,γ )210Bi experiment performed at Institut Laue-Langevin Grenoble at the PF1B cold-neutron facility. The EXILL (EXOGAM at the ILL) multidetector array, consisting of 16 high-purity germanium detectors, was used to detect γ transitions. The mixing ratio of the 320-keV γ ray was defined by minimizing a multivariable χΣ2 function constructed from the coefficients of angular correlation functions for seven pairs of strong transitions in 210Bi. As a result, the almost pure M 1 multipolarity of the 320-keV γ ray was obtained, with an E 2 admixture of less than 0.6% only (95% confidence limit). Based on this multipolarity the neutron-capture cross section leading to the ground state in 210Bi, that decays in turn to radiotoxic 210Po, was determined to be within the limits 21.3(9) and 21.5(9) mb. This result is important for nuclear reactor applications.
Transition elements based on transfinite interpolation
Odabas, Onur R.; Sarigul-Klijn, Nesrin
1993-01-01
In this study the transfinite interpolation methodology, a 'blending-function' method in particular, is utilized for the formulation of transition elements. The method offers a formal way of meeting continuity requirements in a transition element. Element shape functions are derived by blending the continuity requirements of individual boundary segments. The blending directions are naturally orthogonal in rectangular domains therefore interpolation of the boundaries over rectangular 2D and 3D elements can be performed with minimal effort. In triangular domains, however, the choice of blending directions and interpolants is not straightforward. For that reason, two interpolation techniques are proposed for blending of the boundaries of triangular domains. A series of transition elements of various classes compatible with elements of different orders and dimensions is developed and the full potential of the transfinite interpolation, as it applies to element formulation, is explored.
Quantum correlation and quantum phase transition in the one-dimensional extended Ising model
Zhang, Xi-Zheng; Guo, Jin-Liang
2017-09-01
Quantum phase transitions can be understood in terms of Landau's symmetry-breaking theory. Following the discovery of the quantum Hall effect, a new kind of quantum phase can be classified according to topological rather than local order parameters. Both phases coexist for a class of exactly solvable quantum Ising models, for which the ground state energy density corresponds to a loop in a two-dimensional auxiliary space. Motivated by this we study quantum correlations, measured by entanglement and quantum discord, and critical behavior seen in the one-dimensional extended Ising model with short-range interaction. We show that the quantum discord exhibits distinctive behaviors when the system experiences different topological quantum phases denoted by different topological numbers. Quantum discords capability to detect a topological quantum phase transition is more reliable than that of entanglement at both zero and finite temperatures. In addition, by analyzing the divergent behaviors of quantum discord at the critical points, we find that the quantum phase transitions driven by different parameters of the model can also display distinctive critical behaviors, which provides a scheme to detect the topological quantum phase transition in practice.
Energy Technology Data Exchange (ETDEWEB)
Jiménez-Mier, J., E-mail: jimenez@nucleares.unam.mx [Instituto de Ciencias Nucleares, UNAM, 04510 México, DF (Mexico); Olalde-Velasco, P. [Instituto de Ciencias Nucleares, UNAM, 04510 México, DF (Mexico); The Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA 94720 (United States); Herrera-Pérez, G.; Carabalí -Sandoval, G. [Instituto de Ciencias Nucleares, UNAM, 04510 México, DF (Mexico); Chavira, E. [Instituto de Investigaciones en Materiales, UNAM, 04510 México, DF (Mexico); Yang, W.-L.; Denlinger, J. [The Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA 94720 (United States)
2014-10-15
Direct probe of Mott–Hubbard (MH) to charge-transfer (CT) insulator transition in the MF{sub 2} (M = Cr–Zn) family of compounds was observed by combining F K and M L X-ray emission spectra (XES). This transition is evident as a crossover of the F-2p and M-3d occupied states. By combining F K XES data with F K edge X-ray absorption (XAS) data we directly obtained values for the M-3d Hubbard energy (U{sub dd}) and the F-2p to M-3d charge-transfer energy (Δ{sub CT}). Our results are in good agreement with the Zaanen–Sawatzky–Allen theory. We also present three examples where X-ray absorption at the transition metal L{sub 2,3} edges is used to study the oxidation state of various strongly correlated transition metal compounds. The metal oxidation state is obtained by direct comparison with crystal field multiplet calculations. The compounds are CrF{sub 2}, members of the La{sub 1−x}Sr{sub x}CoO{sub 3} family, and the MVO{sub 3} (M = La and Y) perovskites.
A new algebraic transition model based on stress length function
Xiao, Meng-Juan; She, Zhen-Su
2016-11-01
Transition, as one of the two biggest challenges in turbulence research, is of critical importance for engineering application. For decades, the fundamental research seems to be unable to capture the quantitative details in real transition process. On the other hand, numerous empirical parameters in engineering transition models provide no unified description of the transition under varying physical conditions. Recently, we proposed a symmetry-based approach to canonical wall turbulence based on stress length function, which is here extended to describe the transition via a new algebraic transition model. With a multi-layer analytic form of the stress length function in both the streamwise and wall normal directions, the new model gives rise to accurate description of the mean field and friction coefficient, comparing with both the experimental and DNS results at different inlet conditions. Different types of transition process, such as the transition with varying incoming turbulence intensities or that with blow and suck disturbance, are described by only two or three model parameters, each of which has their own specific physical interpretation. Thus, the model enables one to extract physical information from both experimental and DNS data to reproduce the transition process, which may prelude to a new class of generalized transition model for engineering applications.
CORRELATION OF THE GLASS TRANSITION TEMPERATURE OF PLASTICIZED PVC USING A LATTICE FLUID MODEL
A model has been developed to describe the composition dependence of the glass transition temperature (Tg) of polyvinyl chloride (PVC) + plasticizer mixtures. The model is based on Sanchez-Lacombe equation of state and the Gibbs-Di Marzio criterion, which states that th...
A superradiant laser based on two-photon Raman transition of caesium atoms
Liu, Pengfei
2013-01-01
We propose a superradiant laser based on two-photon Raman transition of caesium-133 atoms which collectively emit photons on an ultra narrow transition into the mode of a low Q resonator known as optical bad-cavity regime. The spin-spin correlation which characterizes the collective effect is demonstrated. We theoretically predict that the optical radiation has an extremely narrow linewidth in the 98 (1) *10-2 mHz range, smaller than the transition itself due to collective effects, and a power level of 7 (1)*10-10 W is possible, which can provide a possible new way to realize an optical clock with a millihertz linewidth.
Karolak, M.; Jacob, D.
2016-11-01
We study the impact of the valence and the geometry on the electronic structure and transport properties of different transition metal-benzene sandwich molecules bridging the tips of a Cu nanocontact. Our density-functional calculations show that the electronic transport properties of the molecules depend strongly on the molecular geometry which can be controlled by the nanocontact tips. Depending on the valence of the transition metal center certain molecules can be tuned in and out of half-metallic behaviour facilitating potential spintronics applications. We also discuss our results in the framework of an Anderson impurity model, indicating cases where the inclusion of local correlations alters the ground state qualitatively. For Co and V centered molecules we find indications of an orbital Kondo effect.
Magnetic states, correlation effects and metal-insulator transition in FCC lattice
Timirgazin, M. A.; Igoshev, P. A.; Arzhnikov, A. K.; Irkhin, V. Yu
2016-12-01
The ground-state magnetic phase diagram (including collinear and spiral states) of the single-band Hubbard model for the face-centered cubic lattice and related metal-insulator transition (MIT) are investigated within the slave-boson approach by Kotliar and Ruckenstein. The correlation-induced electron spectrum narrowing and a comparison with a generalized Hartree-Fock approximation allow one to estimate the strength of correlation effects. This, as well as the MIT scenario, depends dramatically on the ratio of the next-nearest and nearest electron hopping integrals {{t}\\prime}/t . In contrast with metallic state, possessing substantial band narrowing, insulator one is only weakly correlated. The magnetic (Slater) scenario of MIT is found to be superior over the Mott one. Unlike simple and body-centered cubic lattices, MIT is the first order transition (discontinuous) for most {{t}\\prime}/t . The insulator state is type-II or type-III antiferromagnet, and the metallic state is spin-spiral, collinear antiferromagnet or paramagnet depending on {{t}\\prime}/t . The picture of magnetic ordering is compared with that in the standard localized-electron (Heisenberg) model.
Revising the Transit Depth-Metallicity Correlation of Kepler's Giant Candidates
Sarkis, Paula; Nehmé, Cyrine
2015-08-01
The two favored mechanisms suggested for forming gas giants are disk instability and core accretion. The latter is the generally accepted mechanism on short orbits. According to this model, one would expect to observe a positive correlation between the transit depth of gas giants and the metallicity of the host star. However, a negative correlation was reported between Kepler’s Q1-Q12 gas giant candidates and the stellar metallicity. Even though this correlation is extremely weak, at the -1.17 sigma, it challenges the theory of planet formation. My work involves revising this correlation now that the number of Kepler's candidates/confirmed has increased. But large-scale surveys, such as Kepler, are subject to selection effects and biases. These biases should be quantified and accounted for in the statistical analysis in order to best understand the correlation. This work reflects the importance of statistical analysis in detecting and characterizing exoplanets, especially in the era of large-scale surveys. Such analysis will lead to a greater understanding of planet formation.
Dynamical scaling in infinitely correlated many-body systems through a quantum phase transition
Acevedo, Oscar Leonardo; Quiroga, Luis; Rodriguez, Ferney Javier; Johnson, Neil
2013-03-01
We assess dynamical scaling of many two-level systems (TLSs) infinitely correlated, either through a mediating radiation mode as in the Dicke Model, or through a direct interaction between TLSs as in the Lipkin-Meshkov-Glick model. Those models are characterized by the presence of a Quantum Phase Transition (QPT) in the thermodynamic limit, and they belong to the same universality class. The assessment is done by means of exact computational simulations of finite-size systems under linear rampings of the interaction parameter crossing the quantum critical point. Our results exhibit significant differences with respect to previous works on dynamical scaling across QPTs in the near-adiabatic regime, which have focused on spin-chain models where correlation lengths can be defined. We have confirmed that in infinitely correlated models an effective system size can play the role of the correlation length in traditional scaling arguments. However, due to the infinite correlation among TLSs, the standard Kibble-Zurek mechanism is not realized as the system cannot fully enter an adiabatic evolution during the ordered phase. Also, in the two-level approximation, a suitable deviation from the standard Landau-Zener protocol must be performed in order to obtain scaling collapse.
Inhomogeneous electronic state near the insulator-to-metal transition in the correlated oxide VO2
Frenzel, A.; Qazilbash, M. M.; Brehm, M.; Chae, Byung-Gyu; Kim, Bong-Jun; Kim, Hyun-Tak; Balatsky, A. V.; Keilmann, F.; Basov, D. N.
2009-09-01
We investigate the percolative insulator-to-metal transition (IMT) in films of the correlated material vanadium dioxide (VO2) . Scattering-type scanning near-field infrared microscopy and atomic force microscopy were used to explore the relationship between the nucleation of metallic regions and the topography in insulating VO2 . We demonstrate that the IMT begins within 10 nm from grain boundaries and crevices by using mean curvature and statistical analysis. We also observe coexistence of insulating and metallic domains in a single crystalline grain that points to intrinsic inhomogeneity in VO2 due to competing electronic phases in the IMT regime.
Metal-Insulator Transition in the Hubbard Model: Correlations and Spiral Magnetic Structures
Timirgazin, Marat A.; Igoshev, Petr A.; Arzhnikov, Anatoly K.; Irkhin, Valentin Yu.
2016-12-01
The metal-insulator transition (MIT) for the square, simple cubic, and body-centered cubic lattices is investigated within the t-t^' Hubbard model at half-filling by using both the generalized for the case of spiral order Hartree-Fock approximation (HFA) and Kotliar-Ruckenstein slave-boson approach. It turns out that the magnetic scenario of MIT becomes superior over the non-magnetic one. The electron correlations lead to some suppression of the spiral phases in comparison with HFA. We found the presence of a metallic antiferromagnetic (spiral) phase in the case of three-dimensional lattices.
Theory of optically forbidden d-d transitions in strongly correlated crystals.
Katsnelson, M I; Lichtenstein, A I
2010-09-29
A general multiband formulation of the linear and nonlinear optical response functions for realistic models of correlated crystals is presented. Dipole-forbidden d-d optical transitions originate from vertex functions, which we consider assuming the locality of an irreducible four-leg vertex. The unified formulation for second- and third-order response functions in terms of the three-leg vertex is suitable for practical calculations in solids. We illustrate the general approach by consideration of intra-atomic spin-flip contributions, with an energy of 2J, where J is a Hund exchange, in the simplest two-orbital model.
Mott insulating states and quantum phase transitions of correlated SU(2 N ) Dirac fermions
Zhou, Zhichao; Wang, Da; Meng, Zi Yang; Wang, Yu; Wu, Congjun
2016-06-01
The interplay between charge and spin degrees of freedom in strongly correlated fermionic systems, in particular of Dirac fermions, is a long-standing problem in condensed matter physics. We investigate the competing orders in the half-filled SU (2 N ) Hubbard model on a honeycomb lattice, which can be accurately realized in optical lattices with ultracold large-spin alkaline-earth fermions. Employing large-scale projector determinant quantum Monte Carlo simulations, we have explored quantum phase transitions from the gapless Dirac semimetals to the gapped Mott insulating phases in the SU(4) and SU(6) cases. Both of these Mott insulating states are found to be columnar valence bond solid (cVBS) and to be absent of the antiferromagnetic Néel ordering and the loop current ordering. Inside the cVBS phases, the dimer ordering is enhanced by increasing fermion components and behaves nonmonotonically as the interaction strength increases. Although the transitions generally should be of first order due to a cubic invariance possessed by the cVBS order, the coupling to gapless Dirac fermions can soften the transitions to second order through a nonanalytic term in the free energy. Our simulations provide important guidance for the experimental explorations of novel states of matter with ultracold alkaline-earth fermions.
Spectral analysis of finite-time correlation matrices near equilibrium phase transitions
Vinayak; Prosen, T.; Buča, B.; Seligman, T. H.
2014-10-01
We study spectral densities for systems on lattices, which, at a phase transition display, power-law spatial correlations. Constructing the spatial correlation matrix we prove that its eigenvalue density shows a power law that can be derived from the spatial correlations. In practice time series are short in the sense that they are either not stationary over long time intervals or not available over long time intervals. Also we usually do not have time series for all variables available. We shall make numerical simulations on a two-dimensional Ising model with the usual Metropolis algorithm as time evolution. Using all spins on a grid with periodic boundary conditions we find a power law, that is, for large grids, compatible with the analytic result. We still find a power law even if we choose a fairly small subset of grid points at random. The exponents of the power laws will be smaller under such circumstances. For very short time series leading to singular correlation matrices we use a recently developed technique to lift the degeneracy at zero in the spectrum and find a significant signature of critical behavior even in this case as compared to high temperature results which tend to those of random matrix models.
Transit Traffic Analysis Zone Delineating Method Based on Thiessen Polygon
Directory of Open Access Journals (Sweden)
Shuwei Wang
2014-04-01
Full Text Available A green transportation system composed of transit, busses and bicycles could be a significant in alleviating traffic congestion. However, the inaccuracy of current transit ridership forecasting methods is imposing a negative impact on the development of urban transit systems. Traffic Analysis Zone (TAZ delineating is a fundamental and essential step in ridership forecasting, existing delineating method in four-step models have some problems in reflecting the travel characteristics of urban transit. This paper aims to come up with a Transit Traffic Analysis Zone delineation method as supplement of traditional TAZs in transit service analysis. The deficiencies of current TAZ delineating methods were analyzed, and the requirements of Transit Traffic Analysis Zone (TTAZ were summarized. Considering these requirements, Thiessen Polygon was introduced into TTAZ delineating. In order to validate its feasibility, Beijing was then taken as an example to delineate TTAZs, followed by a spatial analysis of office buildings within a TTAZ and transit station departure passengers. Analysis result shows that the TTAZs based on Thiessen polygon could reflect the transit travel characteristic and is of in-depth research value.
Transition-Metal-Free Biomolecule-Based Flexible Asymmetric Supercapacitors.
Yang, Yun; Wang, Hua; Hao, Rui; Guo, Lin
2016-09-01
A transition-metal-free asymmetric supercapacitor (ASC) is successfully fabricated based on an earth-abundant biomass derived redox-active biomolecule, named lawsone. Such an ASC exhibits comparable or even higher energy densities than most of the recently reported transition-metal-based ASCs, and this green ASC generation from renewable resources is promising for addressing current issues of electronic hazard processing, high cost, and unsustainability.
Steffen, Jason H; Ford, Eric B; Carter, Joshua A; Desert, Jean-Michel; Fressin, Francois; Holman, Matthew J; Lissauer, Jack J; Moorhead, Althea V; Rowe, Jason F; Ragozzine, Darin; Welsh, William F; Batalha, Natalie M; Borucki, William J; Buchhave, Lars A; Bryson, Steve; Caldwell, Douglas A; Charbonneau, David; Ciardi, David R; Cochran, William D; Endl, Michael; Everett, Mark E; Gautier, Thomas N; Gilliland, Ron L; Girouard, Forrest R; Jenkins, Jon M; Horch, Elliott; Howell, Steve B; Isaacson, Howard; Klaus, Todd C; Koch, David G; Latham, David W; Li, Jie; Lucas, Philip; MacQueen, Phillip J; Marcy, Geoffrey W; McCauliff, Sean; Middour, Christopher K; Morris, Robert L; Mullally, Fergal R; Quinn, Samuel N; Quintana, Elisa V; Shporer, Avi; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Twicken, Joseph D; Van Cleve, Jeffery
2012-01-01
We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-Domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anti-correlations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems Kepler-25, Kepler-26, Kepler-27, and Kepler-28, containing eight planets and one additional planet candidate.
Larson, Nicole I; Neumark-Sztainer, Dianne; Harnack, Lisa; Wall, Melanie; Story, Mary; Eisenberg, Marla E
2009-01-01
To describe changes in calcium and dairy intake during the transition from middle adolescence to young adulthood and to identify baseline correlates of calcium intake in young adulthood. Population-based, 5-year follow-up study (Project EAT: Eating Among Teens). Baseline surveys were completed in Minneapolis/St. Paul, MN schools and by mail at follow-up. Males and females (N = 1521) attending high school at baseline (mean age = 15.9 years) and with a mean age of 20.5 years at follow-up. Calcium intake. Mixed and linear regression methods were used to respectively examine trends and correlates of intake. During the transition to young adulthood, mean daily calcium intakes of females and males decreased by an average of 153 mg and 194 mg respectively. Mealtime milk availability, health/nutrition attitudes, taste preference for milk, healthful weight control behaviors, and peer support for healthful eating at baseline were associated with better follow-up calcium intake. Time spent watching television and lactose intolerance were associated with lower intake at follow-up. Nutrition interventions are needed to counter longitudinal decreases in calcium intake. Interventions targeted to adolescents should address the availability of milk at meals and other identified supports for healthful eating.
Burazeri, Genc; Kark, Jeremy D
2010-07-01
Our aim was to assess alcohol consumption and its correlates in Albania, a predominantly Muslim though largely secular Southeast European republic in transition from rigidly structured socialism to a market-oriented system. A population-based sample of Tirana residents aged 35-74 years was interviewed and examined in 2003-2006 (450 men and 235 women with data on alcohol intake, 65.5% response). Multivariable-adjusted logistic regression was used to assess the association of drinking frequency, quantity and type of drink with socioeconomic, psychosocial and coronary risk characteristics. 30.6% (95%CI=26.3%-34.9%) of men, age-standardized to the 2005 census, and 5.6% (95%CI=2.6%-8.6%) of women reported almost daily intake of alcohol, whereas 17.0% (95%CI=13.4%-20.5%) of men and 46.6% (95%CI=40.2%-53.1%) of women abstained. In men, frequent drinking was positively associated with age and not receiving financial support from close family emigrants, and was strongly inversely related to religious observance in both Muslims and Christians. In women it was associated with smoking and upward social mobility. Alcohol intake was not associated with religious affiliation in either sex. In men, intake of spirits (predominantly raki) and beer were associated with lower socioeconomic indices, smoking and obesity (beer only), whereas wine intake was associated with financial security, being secular, and not smoking. Among men, 11.3% (95%CI=8.3%-14.3%) reported high intakes (> or =210 g of pure alcohol/week) and 6.0% (95%CI=3.8%-8.3%) very high intakes (> or = 420 g/week). High intakes were associated with frequent, rather than episodic, drinking. Our study may be the first to provide information on alcohol intake and its characteristics in an Albanian population sample, one of the few predominantly Muslim countries in Europe. Alcohol consumption in women was extremely low. However, consistent very heavy intake of alcohol appears to be more frequent among Albanian men than in many
Edge-based correlation image registration for multispectral imaging
Nandy, Prabal [Albuquerque, NM
2009-11-17
Registration information for images of a common target obtained from a plurality of different spectral bands can be obtained by combining edge detection and phase correlation. The images are edge-filtered, and pairs of the edge-filtered images are then phase correlated to produce phase correlation images. The registration information can be determined based on these phase correlation images.
Weigand, Susanne; Bol, Roland; Reichert, Barbara; Graf, Alexander; Wiekenkamp, Inge; Stockinger, Michael; Lücke, Andreas; Tappe, Wolfgang; Bogena, Heye; Pütz, Thomas; Amelung, Wulf; Vereecken, Harry
2017-04-01
Understanding natural controls on nitrogen (N) and carbon (C) biogeochemical cycles in time and space is important to estimate human impacts on these cycles. We examined the spatiotemporal relationships between time series of weekly monitored stream- and groundwater N and C (assessed by nitrate; NO3- and dissolved organic carbon; DOC) in the forested Wüstebach catchment (Germany) over a 4-year period (2009- 2013). Median travel transit times (MedTTs) were used to connect hydrological and water chemistry data. In addition to traditional correlation analysis, we applied Wavelet Transform Coherence (WTC) to study variations in the correlation and lag-time between the N and C time series for different time scales. Based on our results, we distinguished three streamwater groups with the following characteristics: (i) subsurface runoff dominated locations with negative C/N correlations, short time lags, strong seasonal fluctuations in concentrations, and short transit times, (ii) groundwater dominated locations, with weaker C/N correlations and lags of several months, small fluctuations in concentrations and longer transit times and (iii) intermediate locations, with moderate seasonal fluctuations, strong C/N correlations, short time lags and moderate transit times. We identified water transit times as key drivers for the relationships in each group and conclude that C and N transport in stream water can be explained by the mixing of groundwater and subsurface runoff. In conclusion, our study revealed that DOC, NO3- concentrations and their ratio in Wüstebach stream waters can be explained by hydrological mixing processes. Complemented with transit times, and hydrochemical time series, the WTC analysis allowed us to discriminate between different water sources (groundwater/subsurface runoff). Overall, we find that in hydrochemical time series studies, e.g. of DOC and NO3-, as in our study, WTC analysis can be a viable tool to identify spatiotemporally dependent
Facilitating Transition to Team Based Design Education
DEFF Research Database (Denmark)
Tollestrup, Christian
2014-01-01
supervisors and programme 3.Reflection of the role in a team, problem based project work 4.The level of information of special expectations from the Industrial Design program towards team and problem based project work. Results indicates that Class receiving the “Survival Kit” improved in the calibration...
Nuclear clocks based on resonant excitation of gamma-transitions
Peik, Ekkehard
2015-01-01
We review the ideas and concepts for a clock that is based on a radiative transition in the nucleus rather than in the electron shell. This type of clock offers advantages like an insensitivity against field-induced systematic frequency shifts and the opportunity to obtain high stability from interrogating many nuclei in the solid state. Experimental work concentrates on the low-energy (about 8 eV) isomeric transition in Th-229. We review the status of the experiments that aim at a direct optical observation of this transition and outline the plans for high-resolution laser spectroscopy experiments.
The chiral phase transition in a random matrix model with molecular correlations
Wettig, T; Weidenmüller, H A; Wettig, Tilo
1995-01-01
The chiral phase transition of QCD is analyzed in a model combining random matrix elements of the Dirac operator with specially chosen non-random ones. The special form of the latter is motivated by the assumption that the fermionic quasi-zero modes associated with instanton and anti-instanton configurations determine the chiral properties of QCD. Our results show that the degree of correlation between these modes plays the decisive role. To reduce the value of the chiral condensate by more than a factor of 2 about 95 percent of the instantons and anti-instantons must form so-called molecules. This conclusion agrees with numerical results of the Stony Brook group.
Decisional procrastination of school-to-work transition: Personality correlates of career indecision
Directory of Open Access Journals (Sweden)
Bańka Augustyn
2015-03-01
Full Text Available Procrastination as putting off until tomorrow what one had intended to do today is well-known tendency in everyday life. In an attempt to understand the character of procrastination in different life-domains, a large body of research has been accumulated over the last decades. This article was aimed to evaluate a specific decisional procrastination of school-to-work transition (SWT that is treated as maturity postponement. Two studies are reported examining SWT procrastination defined as career indecision among Polish students graduating universities. In Study 1 (N=366, attitudinal and identity statuses were analyzed as correlates of career procrastination. A path analysis conducted for the model, which was aimed to explain the influence of career self-efficacy and occupational commitment on career indecision (dependent variable, revealed its very good fitness (RMSEA=.000. Those two independent variables explain 10% of career indecision variance. Stepwise multiple regression analyses conducted to ascertain relationship of five identity statuses (Brzezińska, Piotrowski, 2010 to procrastination measure (career indecision showed that Commitment Making and Ruminative Exploration are strongest predictor variables. In study 2 (N=157, the stepwise multiple regression analyses conducted to ascertain the independent relationship of each of Big Five personality factor revealed that Neuroticism and Extraversion accounts of the most of explained variance of school-to-work transition procrastination.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Four hierarchical cyclothems, superbundlesets, bundlesets,bundles and laminae, have been identified from the Devonian Frasnian-Famennian carbonate strata in Guangxi, South China. Their hierarchical structures, ratio relation ships and sequence in conodont zones are continuous and stable and can be traced across different facies zones and sedi mentary basins. Our data show that hierarchically organized superbundlesets, bundlesets, bundles and laminae correspond to the long eccentricity, eccentricity, obliquity or precession and sub-Milankovitch cycles respectively. Their periods were 400,000, 100,000, 33,333, 16,667 and 8,000-17,000 a, respectively. The ratios of long eccentricity to eccentricity, ec centricity to obliquity, and eccentricity to precession in the Devonian are 1:4, 1:3 and 1:6 respectively. Using these hier archical Milankovitch cyclothems, chronostratigraphical division and correlation can be realized at a resolution of 100 ka or 10 ka at the Frasnian-Famennian transition. The time intervals of the Upper rhenana Zone, linguiformis Zone, and the Lower, Middle and Upper triangularis Zone are 0.6, 0.8, 0.3, 0.3 and 0.3 Ma, respectively. Sea-level changes of the Frasnian-Famennian transition were not coherent and synchronous at the resolution of 100 ka or 10 ka in the basin-slope carbonate sequences of Guangxi, South China.
Microstructure and structural phase transitions in iron-based superconductors
Institute of Scientific and Technical Information of China (English)
Wang Zhen; Cai Yao; Yang Huai-Xin; Tian Huan-Fang; Wang Zhi-Wei; Ma Chao; Chen Zhen
2013-01-01
Crystal structures and microstructural features,such as structural phase transitions,defect structures,and chemical and structural inhomogeneities,are known to have profound effects on the physical properties of superconducting materials.Recently,many studies on the structural properties of Fe-based high-Tc superconductors have been published.This review article will mainly focus on the typical microstructural features in samples that have been well characterized by physical measurements.(i) Certain common structural features are discussed,in particular,the crystal structural features for different superconducting families,the local structural distortions in the Fe2Pn2 (Pn =P,As,Sb) or Fe2Ch2 (Ch =S,Se,Te) blocks,and the structural transformations in the 122 system.(ii) In FeTe(Se) (11 family),the superconductivity,chemical and structural inhomogeneities are investigated and discussed in correlation with superconductivity.(iii) In the K0.8Fe1.6+xSe2 system,we focus on the typical compounds with emphasis on the Fe-vacancy order and phase separations.The microstructural features in other superconducting materials are also briefly discussed.
Facilitating Transition to Team Based Design Education
DEFF Research Database (Denmark)
Tollestrup, Christian
2014-01-01
that even if they had previous experience with project work in teams, they still encounter problems during their first semesters. The PBL based and project oriented Industrial Design Engineering program used in this investigation is very process focused with the objective of opening the process......When students enroll in Problem Based Learning (PBL) and Project-oriented universities at Industrial Design programs, what are their expectations and prerequisites for starting to learn about design and work in teams with design? The short answer is: not as much as they think, studies shows...... supervisors and programme 3.Reflection of the role in a team, problem based project work 4.The level of information of special expectations from the Industrial Design program towards team and problem based project work. Results indicates that Class receiving the “Survival Kit” improved in the calibration...
DSN Beowulf Cluster-Based VLBI Correlator
Rogstad, Stephen P.; Jongeling, Andre P.; Finley, Susan G.; White, Leslie A.; Lanyi, Gabor E.; Clark, John E.; Goodhart, Charles E.
2009-01-01
The NASA Deep Space Network (DSN) requires a broadband VLBI (very long baseline interferometry) correlator to process data routinely taken as part of the VLBI source Catalogue Maintenance and Enhancement task (CAT M&E) and the Time and Earth Motion Precision Observations task (TEMPO). The data provided by these measurements are a crucial ingredient in the formation of precision deep-space navigation models. In addition, a VLBI correlator is needed to provide support for other VLBI related activities for both internal and external customers. The JPL VLBI Correlator (JVC) was designed, developed, and delivered to the DSN as a successor to the legacy Block II Correlator. The JVC is a full-capability VLBI correlator that uses software processes running on multiple computers to cross-correlate two-antenna broadband noise data. Components of this new system (see Figure 1) consist of Linux PCs integrated into a Beowulf Cluster, an existing Mark5 data storage system, a RAID array, an existing software correlator package (SoftC) originally developed for Delta DOR Navigation processing, and various custom- developed software processes and scripts. Parallel processing on the JVC is achieved by assigning slave nodes of the Beowulf cluster to process separate scans in parallel until all scans have been processed. Due to the single stream sequential playback of the Mark5 data, some ramp-up time is required before all nodes can have access to required scan data. Core functions of each processing step are accomplished using optimized C programs. The coordination and execution of these programs across the cluster is accomplished using Pearl scripts, PostgreSQL commands, and a handful of miscellaneous system utilities. Mark5 data modules are loaded on Mark5 Data systems playback units, one per station. Data processing is started when the operator scans the Mark5 systems and runs a script that reads various configuration files and then creates an experiment-dependent status database
Directory of Open Access Journals (Sweden)
Arif Billah Dar
2014-01-01
Full Text Available This paper investigates the synchronization of fixed income markets within Eurozone countries using the new wavelet based methodology. Conventional wavelet methods that use multivariate set of variables to calculate pairwise correlation and cross correlation lead to spurious correlation due to possible relationships with other variables, amplification of type-1 errors, and results, in the form of large set of erroneous graphs. Given these disadvantages of conventional wavelet based pairwise correlation and cross-correlation method, we avoid these limitations by using wavelet multiple correlation and multiple cross correlations to analyze the relationships in Eurozone fixed income markets. Our results based on this methodology indicate that Eurozone fixed income markets are highly integrated and this integration grows with timescales, and hence there is almost no scope for independent monetary policy and bond diversification in these countries.
Subspace decomposition-based correlation matrix multiplication
Institute of Scientific and Technical Information of China (English)
Cheng Hao; Guo Wei; Yu Jingdong
2008-01-01
The correlation matrix, which is widely used in eigenvalue decomposition (EVD) or singular value decomposition (SVD), usually can be denoted by R = E[yiy'i]. A novel method for constructing the correlation matrix R is proposed. The proposed algorithm can improve the resolving power of the signal eigenvalues and overcomes the shortcomings of the traditional subspace methods, which cannot be applied to low SNR. Then the proposed method is applied to the direct sequence spread spectrum (DSSS) signal's signature sequence estimation.The performance of the proposed algorithm is analyzed, and some illustrative simulation results are presented.
Reliability Distribution of Numerical Control Lathe Based on Correlation Analysis
Institute of Scientific and Technical Information of China (English)
Xiaoyan Qi; Guixiang Shen; Yingzhi Zhang; Shuguang Sun; Bingkun Chen
2016-01-01
Combined Reliability distribution with correlation analysis, a new method has been proposed to make Reliability distribution where considering the elements about structure correlation and failure correlation of subsystems. Firstly, we make a sequence for subsystems by means of TOPSIS which comprehends the considerations of Reliability allocation, and introducing a Copula connecting function to set up a distribution model based on structure correlation, failure correlation and target correlation, and then acquiring reliability target area of all subsystems by Matlab. In this method, not only the traditional distribution considerations are concerned, but also correlation influences are involved, to achieve supplementing information and optimizing distribution.
Trinocular Stereo Matching Based on Correlations Between Baselines and Disparities
Institute of Scientific and Technical Information of China (English)
GUANYepeng; GUWeikang
2004-01-01
Gray correlation technique is utilized to take the multi-peak feature points with gray correlation coefficients less than a certain range of maximal correlation coefficient as a potential candidate matching set. There exists the maximal correlation between the correct disparities and their corresponding baselines. A trinocular stereo matching algorithm is proposed based on correlations between the baselines and disparities. After computing the correlations between the baselines and disparities, the unique matches can be determined by maximal correlation coefficient. It is proved that the algorithm proposed is valid and credible by 3-D reconstruction on two pairs of actual natural stereo images.
Transition to knowledge-based economy in Saudi Arabia
Nour, S.
2014-01-01
This paper discusses the progress in transition to knowledge-based economy in Saudi Arabia. As for the methodology, this paper uses updated secondary data obtained from different sources. It uses both descriptive and comparative approaches and uses the OECD definition of knowledge-based economy and
Transition to knowledge-based economy in Saudi Arabia
Nour, S.
2014-01-01
This paper discusses the progress in transition to knowledge-based economy in Saudi Arabia. As for the methodology, this paper uses updated secondary data obtained from different sources. It uses both descriptive and comparative approaches and uses the OECD definition of knowledge-based economy and
Corpus-based Transitivity Biases in Individuals with Aphasia
Directory of Open Access Journals (Sweden)
Gayle DeDe
2015-04-01
Full Text Available Introduction Spontaneous speech samples in individuals with aphasia (IWA have been analyzed to examine many different psycholinguistic features. The present study focused on how IWA use verbs in spontaneous speech. Some verbs can occur in more than one argument structure, but are biased to occur more frequently in one frame than another. For example, "watch" appears in transitive and intransitive structures, but is usually used transitively. This is known as a transitivity bias. It is unknown whether IWA show the same transitivity biases in production as those reported in previous corpus studies with unimpaired individuals. Studies of sentence comprehension have shown that IWA are sensitive to verb biases (e.g., DeDe, 2013. In addition, IWA have shown an overall preference for transitive structures, which are the most frequent structures in English (Roland, Dick, & Elman, 2007. The present study investigated whether IWA show the same pattern of transitive and intransitive biases in spontaneous speech as unimpaired individuals. Method Participants: 278 interviews with IWA were taken from AphasiaBank. The IWA represented a range of aphasia types. Participants were omitted if they spoke English as a second language. Materials: 54 verbs were coded. We chose verbs with the goal of representing different bias types (e.g., transitive, intransitive, sentential complement. Of these, data from 11 transitively biased and 11 intransitively biased verbs (matched for frequency of use and number of syllables are presented here. Coding: All productions of the 54 verbs were coded. The coding protocol was based on Gahl, Jurafsky, and Roland (2004. We implemented an additional level of coding to indicate erroneous verb productions, such as ungrammatical structures and verb agreement errors. Results The (intransitivity biases for IWA were compared to biases from a previously published corpus study (Gahl et al., 2004. The IWA used transitively biased verbs in
Energy Technology Data Exchange (ETDEWEB)
Jonas, R.; Ebrey, T.G. (Univ. of Illinois, Urbana (United States))
1991-01-01
The authors have characterized a unique divalent cation binding site on bacteriorhodopsin which controls the blue-to-purple transition in the purple membrane of Halobacterium halobiu. To identify this site they first showed the correlation between the binding of one Ca{sup 2+} per bacteriorhodopsin and the amount of blue membrane converted to purple membrane. When the free Ca{sup 2+} was reduced below 1 {mu}M, and the pH was set below 5.0 with 0.5 mM citrate, only binding to this high-affinity site was observed, and we could separate its effect from the effect of other divalent cations binding to the membrane under other conditions. Second, the titration of purple membrane showed that protons are taken up in two distinct steps, about 13 with a pK{sub a} of 4-5 and an additional 2 protons with a pK{sub a} for the purple-to-blue transition in 5mM MgSO{sub 4}. Taken together, these observations strongly suggest a direct role for cations in the regulation of the bacteriorhodopsin color under normal conditions. They also found that the intrinsic pK{sub a} for the purple-to-blue transition is about 2.05, suggesting this is the pK{sub a} of the group or groups that, when protonated, lead to the blue membrane. Previously published data can now be interpreted to suggest that the cation regulates an active site near the retinal chromophore. A binding site for the divalent cation that includes Asp-212 and interactions with the protonated Schiff base, Asp-85, Tyr-57, Tyr-185, and Arg-82 is proposed.
Jonas, R; Ebrey, T G
1991-01-01
We have characterized a unique divalent cation binding site on bacteriorhodopsin which controls the blue-to-purple transition in the purple membrane of Halobacterium halobium. To identify this site we first showed the correlation between the binding of one Ca2+ per bacteriorhodopsin and the amount of blue membrane converted to purple membrane. When the free Ca2+ was reduced below 1 microM, and the pH was set below 5.0 with 0.5 mM citrate, only binding to this high-affinity site was observed, and we could separate its effect from the effect of other divalent cations binding to the membrane under other conditions. Second, the titration of purple membrane showed that protons are taken up in two distinct steps, about 13 with a pKa of 4-5 and an additional 2 protons with a pKa of 2.75, in 5 mM MgSO4. The latter is identical to the pKa for the purple-to-blue transition in 5 mM MgSO4. Taken together, these observations strongly suggest a direct role for cations in the regulation of the bacteriorhodopsin color under normal conditions. We have also found that the intrinsic pKa for the purple-to-blue transition is about 2.05, suggesting this is the pKa of the group or groups that, when protonated, lead to the blue membrane. Previously published data can now be interpreted to suggest that the cation regulates an active site near the retinal chromophore. A binding site for the divalent cation that includes Asp-212 and interactions with the protonated Schiff base, Asp-85, Tyr-57, Tyr-185, and Arg-82 is proposed.
Correlation based rotation-invariant corner detector
Mazzaferri, Javier; Ledesma, Silvia
2008-04-01
In this work we introduce a new approach for corner extraction. The method that allows the corner extraction with rotation invariance is composed by a spiral phase function and a binary amplitude. The designed function can be easily implemented as a filter for a Vander Lugt-like optical correlator. A final image obtained with the detector presents intensity peaks in each corner location. Numerical simulation has been performed on a set of synthetic scenes, modulated either in amplitude or phase. Results that show the very good performance of the method are shown.
Room acoustic transition time based on reflection overlap
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Brunskog, Jonas; Jacobsen, Finn
2010-01-01
A transition time is defined based on the temporal overlap of reflected pulses in room impulse responses. Assuming specular reflections only, the temporal distance between adjacent reflections, which is proportional to the volume of a room, is compared with the characteristic width of a pulse...
Room acoustic transition time based on reflection overlap
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Brunskog, Jonas; Jacobsen, Finn
2013-01-01
A transition time is defined based on the temporal overlap of reflected pulses in room impulse responses. Assuming specular reflections only, the temporal distance between adjacent reflections, which is proportional to the volume of a room, is compared with the characteristic width of a pulse...
Korea : Transition to a Knowledge-Based Economy
World Bank
2000-01-01
The report reviews the economic transition in Korea, summarizing the challenge of the knowledge revolution, to the country's development strategy, and the analytical, and policy framework for a knowledge-based economy. It explores the needs to increase overall productivity, and areas of relative inefficiency, namely, inadequate conditions for generation of knowledge, and information; insuf...
Collaborative Filtering Algorithms Based on Kendall Correlation in Recommender Systems
Institute of Scientific and Technical Information of China (English)
YAO Yu; ZHU Shanfeng; CHEN Xinmeng
2006-01-01
In this work, Kendall correlation based collaborative filtering algorithms for the recommender systems are proposed. The Kendall correlation method is used to measure the correlation amongst users by means of considering the relative order of the users' ratings. Kendall based algorithm is based upon a more general model and thus could be more widely applied in e-commerce. Another discovery of this work is that the consideration of only positive correlated neighbors in prediction, in both Pearson and Kendall algorithms, achieves higher accuracy than the consideration of all neighbors, with only a small loss of coverage.
von Essen, C; Mallonn, M; Tingley, B; Marcussen, M
2016-01-01
The transit timing variation technique (TTV) has been widely used to detect and characterize multiple planetary systems. Due to the observational biases imposed mainly by the photometric conditions and instrumentation and the high signal-to-noise required to produce primary transit observations, ground-based data acquired using small telescopes limit the technique to the follow-up of hot Jupiters. However, space-based missions such as Kepler and CoRoT have already revealed that hot Jupiters are mainly found in single systems. Thus, it is natural to question ourselves if we are properly using the observing time at hand carrying out such follow-ups, or if the use of medium-to-low quality transit light curves, combined with current standard techniques of data analysis, could be playing a main role against exoplanetary search via TTVs. The purpose of this work is to investigate to what extent ground-based observations treated with current modelling techniques are reliable to detect and characterize additional pla...
Asymptotic distributions in the projection pursuit based canonical correlation analysis
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, associations between two sets of random variables based on the projection pursuit (PP) method are studied. The asymptotic normal distributions of estimators of the PP based canonical correlations and weighting vectors are derived.
Granato, Enzo
2012-02-01
Phase coherence and vortex order in the fully frustrated XY model on a two-dimensional honeycomb lattice are studied by extensive Monte Carlo simulations using the parallel tempering method and finite-size scaling. No evidence is found for an equilibrium order-disorder or a spin/vortex-glass transition, suggested in previous simulation works. Instead, the scaling analysis of correlations of phase and vortex variables in the full equilibrated system is consistent with a phase transition where the critical temperature vanishes and the correlation lengths diverge as a power law with decreasing temperatures and corresponding critical exponents νph and νv. This behavior and the near agreement of the critical exponents suggest a zero-temperature transition scenario where phase and vortex variables remain coupled on large length scales.
Correlated Node Behavior Model based on Semi Markov Process for MANETS
Azni, A H; Noh, Zul Azri Muhamad; Basari, Abd Samad Hasan; Hussin, Burairah
2012-01-01
This paper introduces a new model for node behavior namely Correlated Node Behavior Model which is an extension of Node Behavior Model. The model adopts semi Markov process in continuous time which clusters the node that has correlation. The key parameter of the process is determined by five probabilistic parameters based on the Markovian model. Computed from the transition probabilities of the semi-Markov process, the node correlation impact on network survivability and resilience can be measure quantitatively. From the result, the quantitative analysis of correlated node behavior on the survivability is obtained through mathematical description, and the effectiveness and rationality of the proposed model are verified through numerical analysis. The analytical results show that the effect from correlated failure nodes on network survivability is much severer than other misbehaviors.
Evolution of worldwide stock markets, correlation structure, and correlation-based graphs.
Song, Dong-Ming; Tumminello, Michele; Zhou, Wei-Xing; Mantegna, Rosario N
2011-08-01
We investigate the daily correlation present among market indices of stock exchanges located all over the world in the time period January 1996 to July 2009. We discover that the correlation among market indices presents both a fast and a slow dynamics. The slow dynamics reflects the development and consolidation of globalization. The fast dynamics is associated with critical events that originate in a specific country or region of the world and rapidly affect the global system. We provide evidence that the short term time scale of correlation among market indices is less than 3 trading months (about 60 trading days). The average values of the nondiagonal elements of the correlation matrix, correlation-based graphs, and the spectral properties of the largest eigenvalues and eigenvectors of the correlation matrix are carrying information about the fast and slow dynamics of the correlation of market indices. We introduce a measure of mutual information based on link co-occurrence in networks in order to detect the fast dynamics of successive changes of correlation-based graphs in a quantitative way.
Several Indicators of Critical Transitions for Complex Diseases Based on Stochastic Analysis.
Wang, Gang; Li, Yuanyuan; Zou, Xiufen
2017-01-01
Many complex diseases (chronic disease onset, development and differentiation, self-assembly, etc.) are reminiscent of phase transitions in a dynamical system: quantitative changes accumulate largely unnoticed until a critical threshold is reached, which causes abrupt qualitative changes of the system. Understanding such nonlinear behaviors is critical to dissect the multiple genetic/environmental factors that together shape the genetic and physiological landscape underlying basic biological functions and to identify the key driving molecules. Based on stochastic differential equation (SDE) model, we theoretically derive three statistical indicators, that is, coefficient of variation (CV), transformed Pearson's correlation coefficient (TPC), and transformed probability distribution (TPD), to identify critical transitions and detect the early-warning signals of the phase transition in complex diseases. To verify the effectiveness of these early-warning indexes, we use high-throughput data for three complex diseases, including influenza caused by either H3N2 or H1N1 and acute lung injury, to extract the dynamical network biomarkers (DNBs) responsible for catastrophic transition into the disease state from predisease state. The numerical results indicate that the derived indicators provide a data-based quantitative analysis for early-warning signals for critical transitions in complex diseases or other dynamical systems.
Transitional clerkship: an experiential course based on workplace learning theory.
Chittenden, Eva H; Henry, Duncan; Saxena, Varun; Loeser, Helen; O'Sullivan, Patricia S
2009-07-01
Starting clerkships is anxiety provoking for medical students. To ease the transition from preclerkship to clerkship curricula, schools offer classroom-based courses which may not be the best model for preparing learners. Drawing from workplace learning theory, the authors developed a seven-day transitional clerkship (TC) in 2007 at the University of California, San Francisco School of Medicine in which students spent half of the course in the hospital, learning routines and logistics of the wards along with their roles and responsibilities as members of ward teams. Twice, they admitted and followed a patient into the next day as part of a shadow team that had no patient-care responsibilities. Dedicated preceptors gave feedback on oral presentations and patient write-ups. Satisfaction with the TC was higher than with the previous year's classroom-based course. TC students felt clearer about their roles and more confident in their abilities as third-year students compared with previous students. TC students continued to rate the transitional course highly after their first clinical rotation. Preceptors were enthusiastic about the course and expressed willingness to commit to future TC preceptorships. The transitional course models an approach to translating workplace learning theory into practice and demonstrates improved satisfaction, better understanding of roles, and increased confidence among new third-year students.
Kim, J H; Oh, Sangjun; Xu, X; Joo, Jinho; Rindfleisch, M; Tomsic, M; Dou, S X
2009-12-01
The change in the lattice parameters or the lattice disorder is claimed as a cause of the slight reduction in the transition temperature by carbon doping in MgB2. In this work, an extensive investigation on the effects of carbohydrate doping has been carried out. It is found that not only the a-axis but also the c-axis lattice parameter increases with the sintering temperature. A linear relation between the unit cell volume and the critical temperature is observed. Compared with the well known correlation between the lattice strain and the critical temperature, the X-ray peak broadening itself shows a closer correlation with the transition temperature. The residual resistivity and the critical temperature are linearly correlated with each other as well and its implication is further discussed.
Energy Technology Data Exchange (ETDEWEB)
Feng, Y.; Jaramillo, R.; Banerjee, A.; Honig, J. M.; Rosenbaum, T. F. (X-Ray Science Division); (Univ. of Chicago); (Harvard Univ.); (Purdue Univ.)
2011-01-01
We use synchrotron x-ray diffraction and electrical transport under pressure to probe both the magnetism and the structure of single-crystal NiS{sub 2} across its Mott-Hubbard transition. In the insulator, the low-temperature antiferromagnetic order results from superexchange among correlated electrons and couples to a (1/2, 1/2, 1/2) superlattice distortion. Applying pressure suppresses the insulating state, but enhances the magnetism as the superexchange increases with decreasing lattice constant. By comparing our results under pressure to previous studies of doped crystals, we show that this dependence of the magnetism on the lattice constant is consistent for both band broadening and band filling. In the high-pressure metallic phase the lattice symmetry is reduced from cubic to monoclinic, pointing to the primary influence of charge correlations at the transition. There exists a wide regime of phase separation that may be a general characteristic of correlated quantum matter.
Non Correlation DWT Based Watermarking Behavior in Different Color Spaces
Directory of Open Access Journals (Sweden)
Mehdi Khalili
2016-01-01
Full Text Available There are two digital watermarking techniques. Digital watermarking techniques based on correlation and digital watermarking techniques that are not based on correlation. In previous work, we proposed a DWT2 based CDMA image watermarking scheme to study the effects of using eight color spaces RGB, YCbCr, JPEG-YCbCr, YIQ, YUV, HSI, HSV and CIELab, on watermarking algorithms based on correlation techniques. This paper proposes a non correlation based image watermarking scheme in wavelet transform domain and tests it in the same color spaces, to develop studying, reach a comprehensive analysis and focus on satisfying the requirements of based non coloration watermarking algorithms. To achieve more security, imperceptibility and robustness of the proposed scheme, first, the binary watermark image encodes by applying ATM, CCM and exclusive OR. Then, the scrambled watermark embeds into intended quantized approximation coefficients of wavelet transform by LSB insertion technique.
Nonlocal Coulomb Correlations in Metals Close to a Charge Order Insulator Transition
Merino, Jaime
2007-07-01
The charge ordering transition induced by the nearest-neighbor Coulomb repulsion V in the 1/4-filled extended Hubbard model is investigated using cellular dynamical mean-field theory. We find a transition to a strongly renormalized charge ordered Fermi liquid at VCO and a metal-to-insulator transition at VMI>VCO. Short range antiferromagnetism occurs concomitantly with the CO transition. Approaching the charge ordered insulator, V≲VMI, the Fermi surface deforms and the scattering rate of electrons develops momentum dependence on the Fermi surface.
Dehghan Firoozabadi, Ali; Diaz, Alejandro; Rojo, Patricio; Soto, Ismael; Mahu, Rodrigo; Becerra Yoma, Nestor; Sedaghati, Elyar
2017-07-01
Exoplanetary atmospheric observations require an exquisite precision in the measurement of the relative flux among wavelengths. In this paper, we aim to provide a new adaptive method to treat light curves before fitting transit parameters in order to minimize systematic effects that affect, for instance, ground-based observations of exo-atmospheres. We propose a neural-network-based method that uses a reference built from the data itself with parameters that are chosen in an unsupervised fashion. To improve the performance of proposed method, K-means clustering and Silhouette criteria are used for identifying similar wavelengths in each cluster. We also constrain under which circumstances our method improves the measurement of planetary-to-stellar radius ratio without producing significant systematic offset. We tested our method in high quality data from WASP-19b and low-quality data from GJ-1214. We succeed in providing smaller error bars for the former when using JKTEBOP, but GJ-1214 light curve was beyond the capabilities of this method to improve as it was expected from our validation tests.
Towards a Physics-Based L-H Transition Model
Schmitz, L.; Rhodes, T. L.; Neiser, T.; Bardoczi, L.; Jenko, F.; Zeng, L.; Gohil, P.; Chrystal, C.; Grierson, B. A.; Eldon, D.; Yan, Z.; McKee, G. R.; Boedo, J.
2016-10-01
L-mode turbulence properties, collisionality, and ion transport fluxes across the separatrix are shown to determine the pre-transition ion poloidal and diamagnetic L-mode edge flow and the shear flow amplification triggering the L-H transition. L-mode ion thermal fluxes increase with density above the power threshold minimum, and are higher in hydrogen than in deuterium plasmas. The long-range toroidal ExB flow correlation at the L-H transition trigger time is observed to peak at intermediate plasma density around the L-H power threshold minimum, and is higher in D-plasmas in comparison to H-plasmas, indicating a possible link between trigger physics and power threshold. The turbulence-driven poloidal ion flow is found decisive for initial turbulence suppression, with a Reynolds stress gradient sufficiently large to account for the measured poloidal flow acceleration in the plateau collisionality. Supported by the US DOE under DE-FG02-08ER54984, DE-FC02-04ER54698, DE-AC02-09CH11466, DE-FG02-89ER53296, DE-FG02-07ER54917.
A correlation consistency based multivariate alarm thresholds optimization approach.
Gao, Huihui; Liu, Feifei; Zhu, Qunxiong
2016-11-01
Different alarm thresholds could generate different alarm data, resulting in different correlations. A new multivariate alarm thresholds optimization methodology based on the correlation consistency between process data and alarm data is proposed in this paper. The interpretative structural modeling is adopted to select the key variables. For the key variables, the correlation coefficients of process data are calculated by the Pearson correlation analysis, while the correlation coefficients of alarm data are calculated by kernel density estimation. To ensure the correlation consistency, the objective function is established as the sum of the absolute differences between these two types of correlations. The optimal thresholds are obtained using particle swarm optimization algorithm. Case study of Tennessee Eastman process is given to demonstrate the effectiveness of proposed method.
The use of spatio-temporal correlation to forecast critical transitions
Karssenberg, D.J.; Bierkens, M.F.P.
2011-01-01
Complex dynamical systems may have critical thresholds at which the system shifts abruptly from one state to another. Such critical transitions have been observed in systems ranging from the human body system to financial markets and the Earth system. Forecasting the timing of critical transitions
WAVELET BASED SPECTRAL CORRELATION METHOD FOR DPSK CHIP RATE ESTIMATION
Institute of Scientific and Technical Information of China (English)
Li Yingxiang; Xiao Xianci; Tai Hengming
2004-01-01
A wavelet-based spectral correlation algorithm to detect and estimate BPSK signal chip rate is proposed. Simulation results show that the proposed method can correctly estimate the BPSK signal chip rate, which may be corrupted by the quadratic characteristics of the spectral correlation function, in a low SNR environment.
Optical correlation based on the fractional Fourier transform.
Granieri, S; Arizaga, R; Sicre, E E
1997-09-10
Some properties of optical correlation based on the fractional Fourier transform are analyzed. For a particular set of fractional orders, a filter is obtained that becomes insensitive to scale variations of the object. An optical configuration is also proposed to carry out the fractional correlation in a flexible way, and some experimental results are shown.
Quantum Encryption Protocol Based on Continuous Variable EPR Correlations
Institute of Scientific and Technical Information of China (English)
HE Guang-Qiang; ZENG Gui-Hua
2006-01-01
A quantum encryption protocol based on Gaussian-modulated continuous variable EPR correlations is proposed. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier (NOPA). For general beam splitter eavesdropping strategy, the mutual information Ⅰ(α, ε)between Alice and Eve is calculated by employing Shannon information theory. Finally the security analysis is presented.
Multiple phase transitions in Pauli limited iron-based superconductors
Ptok, Andrzej
2015-01-01
Specific heat measurements have been successfully used to probe unconventional superconducting phases in one-band heavy-fermion and organic superconductors. We extend the method to study successive phase transitions in multi-band materials such as iron based superconductors. The signatures are multiple peaks in the specific heat, at low temperatures and high magnetic field, which can lead the experimental verification of unconventional superconducting states with non-zero total momentum.
Relating quantum coherence and correlations with entropy-based measures.
Wang, Xiao-Li; Yue, Qiu-Ling; Yu, Chao-Hua; Gao, Fei; Qin, Su-Juan
2017-09-21
Quantum coherence and quantum correlations are important quantum resources for quantum computation and quantum information. In this paper, using entropy-based measures, we investigate the relationships between quantum correlated coherence, which is the coherence between subsystems, and two main kinds of quantum correlations as defined by quantum discord as well as quantum entanglement. In particular, we show that quantum discord and quantum entanglement can be well characterized by quantum correlated coherence. Moreover, we prove that the entanglement measure formulated by quantum correlated coherence is lower and upper bounded by the relative entropy of entanglement and the entanglement of formation, respectively, and equal to the relative entropy of entanglement for all the maximally correlated states.
Grimes, Thomas V.; Wilson, Angela K.; DeYonker, Nathan J.; Cundari, Thomas R.
2007-10-01
The correlation consistent composite approach (ccCA) was applied to the prediction of reaction barrier heights (i.e., transition state energy relative to reactants and products) for a standard benchmark set of reactions comprised of both hydrogen transfer reactions and nonhydrogen transfer reactions (i.e., heavy-atom transfer, SN2, and unimolecular reactions). The ccCA method was compared against G3B for the same set of reactions. Error metrics indicate that ccCA achieves "chemical accuracy" with a mean unsigned error (MUE) of 0.89kcal/mol with respect to the benchmark data for barrier heights; G3B has a mean unsigned error of 1.94kcal/mol. Further, the greater accuracy of ccCA for predicted reaction barriers is compared to other benchmarked literature methods, including density functional (BB1K, MUE =1.16kcal/mol) and wavefunction-based [QCISD(T), MUE =1.10kcal/mol] methods.
Energy Technology Data Exchange (ETDEWEB)
Peterseim, Tobias; Dressel, Martin [1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany); Dietrich, Marc; Polity, Angelika [I. Physikalisches Institut, Justus-Liebig Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen (Germany)
2016-08-21
Thin films of VO{sub 2} on different substrates, Al{sub 2}O{sub 3} and SiO{sub 2}/Si, have been prepared and characterized from room temperature up to 360 K. From the band structure in the rutile metallic phase and in the monoclinic insulating phase, the optical properties are calculated and compared with reflection measurements performed as a function of temperatures. Various interband transitions can be assigned and compared with previous speculations. We extract the parameters of the metallic charge carriers that evolve upon crossing the insulator-to-metal phase transition and find effects by the substrate. The influence of electronic correlations becomes obvious at the phase transition.
NLO in correlation of phase transition and the alkaline metal environment effect on it in KDP family
Energy Technology Data Exchange (ETDEWEB)
Ennaceur, Nasreddine, E-mail: nasr.ennaceur@yahoo.fr [Laboratoire Physico-chimie de l' État Solide, Faculté des Sciences, Université de Sfax, BP 1171, 3000 (Tunisia); Laboratoire de Photonique Quantique et Moléculaire Institut d’Alembert—École Normale Supérieure, 61 avenue du Président Wilson, 94230 Cachan (France); Ledoux-Rak, Isabelle; Singh, Anu [Laboratoire de Photonique Quantique et Moléculaire Institut d’Alembert—École Normale Supérieure, 61 avenue du Président Wilson, 94230 Cachan (France); Mhiri, Tahar; Jarraya, Khaled [Laboratoire Physico-chimie de l' État Solide, Faculté des Sciences, Université de Sfax, BP 1171, 3000 (Tunisia)
2013-11-01
The NaH{sub 2}(P{sub 0.48}As{sub 0.52})O{sub 4}·H{sub 2}O (NDAP) compounds allow favorable conditions to the study of evolution of the NLO response during the non-centrosymmetry phases transitions. In fact, NDAP shows the existence of three reversible non-centrosymmetry phase transitions between 272 and 313 K. These experiments are good tools for probing phase transitions and their nature. In this process, several experiments are useful to reveal not only an agreement between the thermal and the quadratic nonlinear (NLO) studies, but also an attempt amongst other things to correlate the probable effect of the alkaline environment of the KDP family on the effectiveness of the NLO intensity.
Innovations in community-based nursing education: transitioning faculty.
Carter, Kimberly Ferren; Fournier, Maggie; Grover, Susan; Kiehl, Ermalynn M; Sims, Kathleen M
2005-01-01
The health-care climate is changing rapidly and in ways that challenge the abilities of professionals who provide health care. Nursing educators are preparing professional nurses who can think critically, use sound clinical judgment, and participate as full partners in shaping health-care delivery and policy. Therefore, many schools of nursing, including five schools of nursing whose experiences are synthesized in this article, are revising their curricula to a community-based nursing perspective. Strategies to assist faculty in the transition to a community-based nursing curriculum include using change theory, creating a supportive environment, reducing tension and isolation, and evaluating. Potential challenges during transition include addressing grief and loss, overcoming the tedium of curricular development, moving the revision along while allowing opportunities for faculty input and consensus building, exploring alternative pedagogies, managing faculty workload and qualification issues, and preparing for transition. Outcomes include a more complete understanding of the community client as a partner in the delivery of health care, increased visibility and role modeling to potential future candidates for health careers, cultural transformations within a university, and promotion of the overall health of a community.
Institute of Scientific and Technical Information of China (English)
SHAO Yuanzhi; ZHONG Weirong; HE Zhenhui
2005-01-01
We report the nonequilibrium dynamical phase transition (NDPT) appearing in a kinetic Ising spin system (ISS) subject to the joint application of a deterministic external field and the stochastic mutually correlated noises simultaneously. A time-dependent Ginzburg-Landau stochastic differential equation, including an oscillating modulation and the correlated multiplicative and additive white noises, was addressed and the numerical solution to the relevant Fokker-Planck equation was presented on the basis of an average-period approach of driven field. The correlated white noises and the deterministic modulation induce a kind of dynamic symmetry-breaking order, analogous to the stochastic resonance in trend, in the kinetic ISS, and the reentrant transition has been observed between the dynamic disorder and order phases when the intensities of multiplicative and additive noises were changing. The dependencies of a dynamic order parameter Q upon the intensities of additive noise A and multiplicative noise M, the correlation λ between two noises, and the amplitude of applied external field h were investigated quantitatively and visualized vividly. Here a brief discussion is given to outline the underlying mechanism of the NDPT in a kinetic ISS driven by an external force and correlated noises.
Howerter, Wendy Lou
2011-01-01
This correlational study samples twelfth grade (senior) students in one central Midwest high school and examines their participation in credit-based transition programs and their changes in educational aspirations. Surveys and community college data are used to collect quantitative data to address six research questions. Using Hossler and…
Existence problem of optical correlation based pattern recognition
Institute of Scientific and Technical Information of China (English)
ZHANG; Yanxin(张延炘); LI; Sumei(李素梅)
2003-01-01
The existence problem of optical correlation based pattern recognition, namely its range of validity and its limitation, is discussed in this paper conjointly with the function approximation theory of neural networks. The conclusion is that only if the sets to be recognized are linearly separable (which is rare) or the subsets, in which a segmental sample of the targets is involved,are linearly separable, can the classical 4f optical correlation system carry out the task of recognition inerrably. The recognition principle of a joint transform correlator is the same as that of a 4f system, and so is its range of validities. Based on the demonstration of the existence problem of optical correlation based pattern recognition an evaluation on some important problems that were studied in this field over the past 40 years is presented explicitly.
Kawano, Taro; Katayama, Ikufumi; Ohara, Jun; Ashida, Masaaki; Takeda, Jun
2014-01-01
Intermolecular vibrations relevant to optically and thermally induced magnetic phase transitions between low temperature (LT) diamagnetic and high temperature (HT) paramagnetic phases in a strongly correlated organic radical 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) crystal have been investigated using broadband terahertz (THz) time-domain spectroscopy. Two absorption bands with different polarizations were clearly observed at 1.3 and 4.0 THz in the LT phase, whilst absent in the HT phase. ...
Independet Component Analyses of Ground-based Exoplanetary Transits
Silva Martins-Filho, Walter; Griffith, Caitlin Ann; Pearson, Kyle; Waldmann, Ingo; Biddle, Lauren; Zellem, Robert Thomas; Alvarez-Candal, Alvaro
2016-10-01
Most observations of exoplanetary atmospheres are conducted when a "Hot Jupiter" exoplanet transits in front of its host star. These Jovian-sized planets have small orbital periods, on the order of days, and therefore a short transit time, making them more ameanable to observations. Measurements of Hot Jupiter transits must achieve a 10-4 level of accuracy in the flux to determine the spectral modulations of the exoplanetary atmosphere. In order to accomplish this level of precision, we need to extract systematic errors, and, for ground-based measurements, the effects of Earth's atmosphere, from the signal due to the exoplanet, which is several orders of magnitudes smaller. Currently, the effects of the terrestrial atmosphere and the some of the time-dependent systematic errors are treated by dividing the host star by a reference star at each wavelength and time step of the transit. More recently, Independent Component Analyses (ICA) have been used to remove systematic effects from the raw data of space-based observations (Waldmann 2014,2012; Morello et al.,2015,2016). ICA is a statistical method born from the ideas of the blind-source separation studies, which can be used to de-trend several independent source signals of a data set (Hyvarinen and Oja, 2000). One strength of this method is that it requires no additional prior knowledge of the system. Here, we present a study of the application of ICA to ground-based transit observations of extrasolar planets, which are affected by Earth's atmosphere. We analyze photometric data of two extrasolar planets, WASP-1b and GJ3470b, recorded by the 61" Kuiper Telescope at Stewart Observatory using the Harris B and U filters. The presentation will compare the light curve depths and their dispersions as derived from the ICA analysis to those derived by analyses that ratio of the host star to nearby reference stars.References: Waldmann, I.P. 2012 ApJ, 747, 12, Waldamann, I. P. 2014 ApJ, 780, 23; Morello G. 2015 ApJ, 806
[Electroencephalogram Feature Selection Based on Correlation Coefficient Analysis].
Zhou, Jinzhi; Tang, Xiaofang
2015-08-01
In order to improve the accuracy of classification with small amount of motor imagery training data on the development of brain-computer interface (BCD systems, we proposed an analyzing method to automatically select the characteristic parameters based on correlation coefficient analysis. Throughout the five sample data of dataset IV a from 2005 BCI Competition, we utilized short-time Fourier transform (STFT) and correlation coefficient calculation to reduce the number of primitive electroencephalogram dimension, then introduced feature extraction based on common spatial pattern (CSP) and classified by linear discriminant analysis (LDA). Simulation results showed that the average rate of classification accuracy could be improved by using correlation coefficient feature selection method than those without using this algorithm. Comparing with support vector machine (SVM) optimization features algorithm, the correlation coefficient analysis can lead better selection parameters to improve the accuracy of classification.
Directory of Open Access Journals (Sweden)
Sheetal Patel
Full Text Available OBJECTIVE: Little is known about HIV infection and the related vulnerabilities of young people living in resource-scarce, post-emergency transit camps that are now home to thousands of Internally Displaced Persons (IDPs following two decades of war in northern Uganda. The objective of this analysis was to assess the prevalence and correlates of HIV infection among young people living in post-conflict transition in Gulu District, northern Uganda. METHODS: In 2010, a cross-sectional demographic and behavioural survey was conducted in two of Gulu District's sub-counties with 384 purposively selected transit camp residents aged 15 to 29 years. Biological specimens were collected for rapid HIV testing in the field and confirmatory laboratory testing. Multivariable logistic regression identified independent determinants of HIV infection. RESULTS: HIV prevalence was alarmingly high at 12.8% (95% CI: 9.6%, 16.5%. The strongest determinant of HIV infection among young people was a non-consensual sexual debut (adjusted odds ratio [AOR], 9.88; 95% CI: 1.70-18.06. Residing in Awach sub-county (AOR, 2.93; 95% CI: 1.28-6.68, experiencing STI symptoms in the previous 12 months (AOR, 2.36; 95% CI: 1.43-6.17, and practicing dry sex (AOR, 2.31; 95% CI: 1.04-5.13 were other key determinants of HIV infection. CONCLUSIONS: Study findings contribute to filling an important gap in epidemiological evidence and are useful for planning public health interventions in northern Uganda that effectively target young people in post-conflict transition and support them in the resettlement process. Findings serve to recommend reaching beyond traditional prevention programming in a way more effectively beneficial to young people in post-conflict settings by developing population-specific responses sensitive to local contexts and sufficient to address the underlying causes of the complex risk factors influencing the spread of HIV.
FPGA design of correlation-based pattern recognition
Jridi, Maher; Alfalou, Ayman
2017-05-01
Optical/Digital pattern recognition and tracking based on optical/digital correlation are a well-known techniques to detect, identify and localize a target object in a scene. Despite the limited number of treatments required by the correlation scheme, computational time and resources are relatively high. The most computational intensive treatment required by the correlation is the transformation from spatial to spectral domain and then from spectral to spatial domain. Furthermore, these transformations are used on optical/digital encryption schemes like the double random phase encryption (DRPE). In this paper, we present a VLSI architecture for the correlation scheme based on the fast Fourier transform (FFT). One interesting feature of the proposed scheme is its ability to stream image processing in order to perform correlation for video sequences. A trade-off between the hardware consumption and the robustness of the correlation can be made in order to understand the limitations of the correlation implementation in reconfigurable and portable platforms. Experimental results obtained from HDL simulations and FPGA prototype have demonstrated the advantages of the proposed scheme.
Color-image retrieval based on fuzzy correlation
Institute of Scientific and Technical Information of China (English)
ZHAI Hongchen; LIANG Yanmei; MU Guoguang
2004-01-01
We report a method of color-image retrieval based on fuzzy correlation, in which α-cut relations in fuzzy set theory are applied to defining color match and height match of color peaks for synthesizing fuzzy correlation of two color histograms, and RGB space is partitioned into six sub-regions in the experiment for the regional color comparisons. Experimental results show that the efficiency of the color-image retrieval can be effectively improved by this approach.
Markov chaotic sequences for correlation based watermarking schemes
Energy Technology Data Exchange (ETDEWEB)
Tefas, A.; Nikolaidis, A.; Nikolaidis, N.; Solachidis, V.; Tsekeridou, S.; Pitas, I. E-mail: pitas@zeus.csd.auth.gr
2003-07-01
In this paper, statistical analysis of watermarking schemes based on correlation detection is presented. Statistical properties of watermark sequences generated by piecewise-linear Markov maps are exploited, resulting in superior watermark detection reliability. Correlation/spectral properties of such sequences are easily controllable, a fact that affects the watermarking system performance. A family of chaotic maps, namely the skew tent map family, is proposed for use in watermarking schemes.
Li, Weizhen; Wu, Peiyi
2009-08-01
The crystal structure transition of syndiotactic polystyrene film from the helical conformation to the more stable planar zigzag conformation during a heating process was studied using Fourier transform infrared (FT-IR) spectroscopy in combination with two-dimensional (2D) correlation analysis and perturbation-correlation moving-window 2D analysis. The sequence of different conformations during the transition was investigated by analyzing two-dimensional FT-IR correlation spectra in the spectral ranges of 800-700 cm(-1) and 600-500 cm(-1). It was observed that the conformation of delta helical changes prior to gamma helical, and the gamma helical phase is faster than the alpha' planar zigzag phase. By utilizing the 2D asynchronous correlation spectra, the 744 cm(-1) band, which is usually incorporated in the broad 750 cm(-1) band, can now be uniquely attributed as the alpha' zigzag configuration for the first time. Furthermore, by employing thermal perturbation, the shorter helical segments consisting of m = 7-12 and m = 12-20 monomeric units were disturbed in a shorter time than the longer helical segments m = 20-30 during the heating process.
Directory of Open Access Journals (Sweden)
Alloul H.
2012-03-01
Full Text Available The discovery in 1991 of high temperature superconductivity (SC in A3C60 compounds, where A is an alkali ion, has been rapidly ascribed to a BCS mechanism, in which the pairing is mediated by on ball optical phonon modes. While this has lead to consider that electronic correlations were not important in these compounds, further studies of various AnC60 with n=1, 2, 4 allowed to evidence that their electronic properties cannot be explained by a simple progressive band filling of the C60 six-fold degenerate t1u molecular level. This could only be ascribed to the simultaneous influence of electron correlations and Jahn-Teller Distortions (JTD of the C60 ball, which energetically favour evenly charged C60 molecules. This is underlined by the recent discovery of two expanded fulleride Cs3C60 isomeric phases which are Mott insulators at ambient pressure. Both phases undergo a pressure induced first order Mott transition to SC with a (p, T phase diagram displaying a dome shaped SC, a common situation encountered nowadays in correlated electron systems. NMR experiments allowed us to study the magnetic properties of the Mott phases and to evidence clear deviations from BCS expectations near the Mott transition. So, although SC involves an electron-phonon mechanism, the incidence of electron correlations has an importance on the electronic properties, as had been anticipated from DMFT calculations.
Jamming transitions in force-based models for pedestrian dynamics
Chraibi, Mohcine; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin
2015-01-01
Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a new force-based model which produces realistic jam dynamics without the appearance of u...
Phase Transition in Distance-Based Phylogeny Reconstruction
Roch, Sebastien
2011-01-01
We introduce a new distance-based phylogeny reconstruction technique which provably achieves, at sufficiently short branch lengths, a logarithmic sequence-length requirement---improving significantly over previous polynomial bounds for distance-based methods and matching existing results for general methods. The technique is based on an averaging procedure that implicitly reconstructs ancestral sequences. In the same token, we extend previous results on phase transitions in phylogeny reconstruction to general time-reversible models. More precisely, we show that in the so-called Kesten-Stigum zone (roughly, a region of the parameter space where ancestral sequences are well approximated by "linear combinations" of the observed sequences) sequences of length $O(\\log n)$ suffice for reconstruction when branch lengths are discretized. Here $n$ is the number of extant species. Our results challenge, to some extent, the conventional wisdom that estimates of evolutionary distances alone carry significantly less infor...
Superfluid density and superconducting transition temperature in Bi-based cuprate single crystals.
Gasparov, L.; Tanner, D.; Berger, H.; Forro, L.; Margaritondo, G.
2000-03-01
We present temperature-dependent reflectance measurements for Bi-based cuprate single crystals in the frequency range from 100 to 40,000 cm-1 (0.012--5 eV). The optical conductivity is obtained by Kramers-Kronig analysis. We compare differently doped Bi-2212 (particularly in the underdoped regime) as well as Pr-doped Bi-2212 crystals by analyzing optical conductivity in the framework of a two-fluid approach. This approach allows us to study correlations between superfluid density and superconducting transition temperature of these materials.
Strong correlation effects on topological quantum phase transitions in three dimensions
Amaricci, A.; Budich, J. C.; Capone, M.; Trauzettel, B.; Sangiovanni, G.
2016-06-01
We investigate the role of short-ranged electron-electron interactions in a paradigmatic model of three-dimensional topological insulators, using dynamical mean-field theory and focusing on nonmagnetically ordered solutions. The noninteracting band structure is controlled by a mass term M , whose value discriminates between three different insulating phases, a trivial band insulator and two distinct topologically nontrivial phases. We characterize the evolution of the transitions between the different phases as a function of the local Coulomb repulsion U and find a remarkable dependence of the U -M phase diagram on the value of the local Hund's exchange coupling J . However, regardless of the value of J , following the evolution of the topological transition line between a trivial band insulator and a topological insulator, we find a critical value of U separating a continuous transition from a first-order one. When the Hund's coupling is significant, a Mott insulator is stabilized at large U . In proximity of the Mott transition we observe the emergence of an anomalous "Mott-like" strong topological insulator state.
Effective information spreading based on local information in correlated networks
Gao, Lei; Pan, Liming; Tang, Ming; Zhang, Hai-Feng
2016-01-01
Using network-based information to facilitate information spreading is an essential task for spreading dynamics in complex networks, which will benefit the promotion of technical innovations, healthy behaviors, new products, etc. Focusing on degree correlated networks, we propose a preferential contact strategy based on the local network structure and local informed density to promote the information spreading. During the spreading process, an informed node will preferentially select a contact target among its neighbors, basing on their degrees or local informed densities. By extensively implementing numerical simulations in synthetic and empirical networks, we find that when only consider the local structure information, the convergence time of information spreading will be remarkably reduced if low-degree neighbors are favored as contact targets. Meanwhile, the minimum convergence time depends non-monotonically on degree-degree correlation, and moderate correlation coefficients result in most efficient info...
Correlation theory-based signal processing method for CMF signals
Shen, Yan-lin; Tu, Ya-qing
2016-06-01
Signal processing precision of Coriolis mass flowmeter (CMF) signals affects measurement accuracy of Coriolis mass flowmeters directly. To improve the measurement accuracy of CMFs, a correlation theory-based signal processing method for CMF signals is proposed, which is comprised of the correlation theory-based frequency estimation method and phase difference estimation method. Theoretical analysis shows that the proposed method eliminates the effect of non-integral period sampling signals on frequency and phase difference estimation. The results of simulations and field experiments demonstrate that the proposed method improves the anti-interference performance of frequency and phase difference estimation and has better estimation performance than the adaptive notch filter, discrete Fourier transform and autocorrelation methods in terms of frequency estimation and the data extension-based correlation, Hilbert transform, quadrature delay estimator and discrete Fourier transform methods in terms of phase difference estimation, which contributes to improving the measurement accuracy of Coriolis mass flowmeters.
Effective information spreading based on local information in correlated networks
Gao, Lei; Wang, Wei; Pan, Liming; Tang, Ming; Zhang, Hai-Feng
2016-12-01
Using network-based information to facilitate information spreading is an essential task for spreading dynamics in complex networks. Focusing on degree correlated networks, we propose a preferential contact strategy based on the local network structure and local informed density to promote the information spreading. During the spreading process, an informed node will preferentially select a contact target among its neighbors, basing on their degrees or local informed densities. By extensively implementing numerical simulations in synthetic and empirical networks, we find that when only consider the local structure information, the convergence time of information spreading will be remarkably reduced if low-degree neighbors are favored as contact targets. Meanwhile, the minimum convergence time depends non-monotonically on degree-degree correlation, and a moderate correlation coefficient results in the most efficient information spreading. Incorporating the local informed density information into contact strategy, the convergence time of information spreading can be further reduced, and be minimized by an moderately preferential selection.
Energy Technology Data Exchange (ETDEWEB)
Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru; Pavlov, N. S.; Sadovskii, M. V. [Russian Academy of Sciences, Institute for Electrophysics, Ural Branch (Russian Federation)
2013-04-15
We discuss the recently proposed LDA' + DMFT approach providing a consistent parameter-free treatment of the so-called double counting problem arising within the LDA + DMFT hybrid computational method for realistic strongly correlated materials. In this approach, the local exchange-correlation portion of the electron-electron interaction is excluded from self-consistent LDA calculations for strongly correlated electronic shells, e.g., d-states of transition metal compounds. Then, the corresponding double-counting term in the LDA' + DMFT Hamiltonian is consistently set in the local Hartree (fully localized limit, FLL) form of the Hubbard model interaction term. We present the results of extensive LDA' + DMFT calculations of densities of states, spectral densities, and optical conductivity for most typical representatives of two wide classes of strongly correlated systems in the paramagnetic phase: charge transfer insulators (MnO, CoO, and NiO) and strongly correlated metals (SrVO{sub 3} and Sr{sub 2}RuO{sub 4}). It is shown that for NiO and CoO systems, the LDA' + DMFT approach qualitatively improves the conventional LDA + DMFT results with the FLL type of double counting, where CoO and NiO were obtained to be metals. Our calculations also include transition-metal 4s-states located near the Fermi level, missed in previous LDA + DMFT studies of these monoxides. General agreement with optical and the X-ray experiments is obtained. For strongly correlated metals, the LDA' + DMFT results agree well with the earlier LDA + DMFT calculations and existing experiments. However, in general, LDA' + DMFT results give better quantitative agreement with experimental data for band gap sizes and oxygen-state positions compared to the conventional LDA + DMFT method.
Nekrasov, I. A.; Pavlov, N. S.; Sadovskii, M. V.
2013-04-01
We discuss the recently proposed LDA' + DMFT approach providing a consistent parameter-free treatment of the so-called double counting problem arising within the LDA + DMFT hybrid computational method for realistic strongly correlated materials. In this approach, the local exchange-correlation portion of the electron-electron interaction is excluded from self-consistent LDA calculations for strongly correlated electronic shells, e.g., d-states of transition metal compounds. Then, the corresponding double-counting term in the LDA' + DMFT Hamiltonian is consistently set in the local Hartree (fully localized limit, FLL) form of the Hubbard model interaction term. We present the results of extensive LDA' + DMFT calculations of densities of states, spectral densities, and optical conductivity for most typical representatives of two wide classes of strongly correlated systems in the paramagnetic phase: charge transfer insulators (MnO, CoO, and NiO) and strongly correlated metals (SrVO3 and Sr2RuO4). It is shown that for NiO and CoO systems, the LDA' + DMFT approach qualitatively improves the conventional LDA + DMFT results with the FLL type of double counting, where CoO and NiO were obtained to be metals. Our calculations also include transition-metal 4 s-states located near the Fermi level, missed in previous LDA + DMFT studies of these monoxides. General agreement with optical and the X-ray experiments is obtained. For strongly correlated metals, the LDA' + DMFT results agree well with the earlier LDA + DMFT calculations and existing experiments. However, in general, LDA' + DMFT results give better quantitative agreement with experimental data for band gap sizes and oxygen-state positions compared to the conventional LDA + DMFT method.
A mechanism-based approach for absorption modeling: the Gastro-Intestinal Transit Time (GITT) model.
Hénin, Emilie; Bergstrand, Martin; Standing, Joseph F; Karlsson, Mats O
2012-06-01
Absorption models used in the estimation of pharmacokinetic drug characteristics from plasma concentration data are generally empirical and simple, utilizing no prior information on gastro-intestinal (GI) transit patterns. Our aim was to develop and evaluate an estimation strategy based on a mechanism-based model for drug absorption, which takes into account the tablet movement through the GI transit. This work is an extension of a previous model utilizing tablet movement characteristics derived from magnetic marker monitoring (MMM) and pharmacokinetic data. The new approach, which replaces MMM data with a GI transit model, was evaluated in data sets where MMM data were available (felodipine) or not available (diclofenac). Pharmacokinetic profiles in both datasets were well described by the model according to goodness-of-fit plots. Visual predictive checks showed the model to give superior simulation properties compared with a standard empirical approach (first-order absorption rate + lag-time). This model represents a step towards an integrated mechanism-based NLME model, where the use of physiological knowledge and in vitro–in vivo correlation helps fully characterize PK and generate hypotheses for new formulations or specific populations.
Coherent Network Optimizing of Rail-Based Urban Mass Transit
Directory of Open Access Journals (Sweden)
Ying Zhang
2012-01-01
Full Text Available An efficient public transport is more than ever a crucial factor when it comes to the quality of life and competitiveness of many cities and regions in Asia. In recent years, the rail-based urban mass transit has been regarded as one of the key means to overcoming the great challenges in Chinese megacities. The purpose of this study is going to develop a coherent network optimizing for rail-based urban mass transit to find the best alternatives for the user and to demonstrate how to meet sustainable development needs and to match the enormous capacity requirements simultaneously. This paper presents an introduction to the current situation of the important lines, and transfer points in the metro system Shanghai. The insufficient aspects are analyzed and evaluated; while the optimizing ideas and measurements are developed and concreted. A group of examples are used to illustrate the approach. The whole study could be used for the latest reference for other megacities which have to be confronted with the similar situations and processes with enormous dynamic travel and transport demands.
Sella size and jaw bases - Is there a correlation???
Directory of Open Access Journals (Sweden)
Neha
2016-01-01
Full Text Available Introduction: Sella turcica is an important cephalometric structure and attempts have been made in the past to correlate its dimensions to the malocclusion. However, no study has so far compared the size of sella to the jaw bases that determine the type of malocclusion. The present study was undertaken to find out any such correlation if it exists. Materials and Methods: Lateral cephalograms of 110 adults consisting of 40 Class I, 40 Class II, and 30 Class III patients were assessed for the measurement of sella length, width, height, and area. The maxillary length, mandibular ramus height, and body length were also measured. The sella dimensions were compared among three malocclusion types by one-way ANOVA. Pearson correlation was calculated between the jaw size and sella dimensions. Furthermore, the ratio of jaw base lengths and sella area were calculated. Results and Conclusion: Mean sella length, width and area were found to be greatest in Class III, followed by Class I and least in Class II though the results were not statistically significant. 3 out of 4 measured dimensions of sella, correlated significantly with mandibular ramus and body length each. However, only one dimension of sella showed significant correlation with maxilla. The mandibular ramus and body length show a nearly constant ratio to sella area (0.83–0.85, 0.64–0.65, respectively in all the three malocclusions. Thus, mandible has a definite and better correlation to the size of sella turcica.
Repeat Sequences and Base Correlations in Human Y Chromosome Palindromes
Institute of Scientific and Technical Information of China (English)
Neng-zhi Jin; Zi-xian Liu; Yan-jiao Qi; Wen-yuan Qiu
2009-01-01
On the basis of information theory and statistical methods, we use mutual information, n-tuple entropy and conditional entropy, combined with biological characteristics, to analyze the long range correlation and short range correlation in human Y chromosome palindromes. The magnitude distribution of the long range correlation which can be reflected by the mutual information is P5>P5a>P5b (P5a and P5b are the sequences that replace solely Alu repeats and all interspersed repeats with random uncorrelated sequences in human Y chromosome palindrome 5, respectively); and the magnitude distribution of the short range correlation which can be reflected by the n-tuple entropy and the conditional entropy is P5>P5a>P5b>random uncorrelated sequence. In other words, when the Alu repeats and all interspersed repeats replace with random uncorrelated sequence, the long range and short range correlation decrease gradually. However, the random uncorrelated sequence has no correlation. This research indicates that more repeat sequences result in stronger correlation between bases in human Y chromosome. The analyses may be helpful to understand the special structures of human Y chromosome palindromes profoundly.
Transition metal dichalcogenides based saturable absorbers for pulsed laser technology
Mohanraj, J.; Velmurugan, V.; Sivabalan, S.
2016-10-01
Ultrashort pulsed laser is an indispensable tool for the evolution of photonic technology in the present and future. This laser has been progressing tremendously with new pulse regimes and incorporating novel devices inside its cavity. Recently, a nanomaterial based saturable absorber (SA) was used in ultrafast laser that has improved the lasing performance and caused a reduction in the physical dimension when compared to conventional SAs. To date, the nanomaterials that are exploited for the development of SA devices are carbon nanotubes, graphene, topological insulators, transition metal dichalcogenides (TMDs) and black phosphorous. These materials have unique advantages such as high nonlinear optical response, fiber compatibility and ease of fabrication. In these, TMDs are prominent and an emerging two-dimensional nanomaterial for photonics and optoelectronics applications. Therefore, we review the reports of Q-switched and mode-locked pulsed lasers using TMDs (specifically MoS2, MoSe2, WS2 and WSe2) based SAs.
Shabunina, E. V.; Spirin, D. V.; Popov, A. A.; Udodov, V. N.; Potekaev, A. I.
2013-05-01
Using a Monte Carlo simulation, the effect of external field, temperature, system's dimensions and interaction of non-nearest neighbors on the relaxation time and critical indices of an antiferromagnetic-to-ferromagnetic phase transition is investigated taking into account nonmagnetic impurities within a modified, onedimensional, nanosized Ising model. It is shown that the non-equilibrium processes taking place in the magnetic material could be classified as fast and slow, whose velocities differ by more than a thousand times. In the case of fast processes, metastable (including ferromagnetic) states (observed experimentally) are the first to form, while in the case of slow processes the system transits into a stable state. The behavior of the dynamic critical exponent ( z) and static correlation-length critical exponent ( ν) is revealed for the model of a 1D ferromagnetic for the case of arbitrary concentrations of nonmagnetic impurities.
Deng, Jian; Sun, Liping; Teng, Lubao; Pan, Dingyi; Shao, Xueming
2016-09-01
We study numerically the propulsive wakes produced by a flapping foil. Both pure pitching and pure heaving motions are considered, respectively, at a fixed Reynolds number of Re = 1700. As the major innovation of this paper, we find an interesting coincidence that the efficiency maximum agrees well with the 2D-3D transition boundary, by plotting the contours of propulsive efficiency in the frequency-amplitude parametric space and comparing to the transition boundaries. Although there is a lack of direct 3D simulations, it is reasonable to conjecture that the propulsive efficiency increases with Strouhal number until the wake transits from a 2D state to a 3D state. By comparing between the pure pitching motion and the pure heaving motion, we find that the 2D-3D transition occurs earlier for the pure heaving foil than that of the pure pitching foil. Consequently, the efficiency for the pure heaving foil peaks more closely to the wake deflection boundary than that of the pure pitching foil. Furthermore, since we have drawn the maps on the same parametric space with the same Reynolds number, it is possible to make a direct comparison in the propulsive efficiency between a pure pitching foil and a pure heaving foil. We note that the maximum efficiency for a pure pitching foil is 15.6%, and that of a pure heaving foil is 17%, indicating that the pure heaving foil has a slightly better propulsive performance than that of the pure pitching foil for the currently studied Reynolds number.
Semmler, Denis; Byczuk, Krzysztof; Hofstetter, Walter
2009-01-01
Strongly correlated fermions in a crystal or in an optical lattice in the presence of binary alloy disorder are investigated. We employ the statistical dynamical mean-field theory, which incorporates both, local fluctuations due to disorder and local correlations due to interaction, to solve the Anderson-Hubbard model. Localization due to disorder is studied by means of the probability distribution function of the local density of states. We obtain a complete paramagnetic ground state phase d...
Generalized Correlation Coefficient Based on Log Likelihood Ratio Test Statistic
Directory of Open Access Journals (Sweden)
Liu Hsiang-Chuan
2016-01-01
Full Text Available In this paper, I point out that both Joe’s and Ding’s strength statistics can only be used for testing the pair-wise independence, and I propose a novel G-square based strength statistic, called Liu’s generalized correlation coefficient, it can be used to detect and compare the strength of not only the pair-wise independence but also the mutual independence of any multivariate variables. Furthermore, I proved that only Liu’s generalized correlation coefficient is strictly increasing on its number of variables, it is more sensitive and useful than Cramer’s V coefficient, in other words, Liu generalized correlation coefficient is not only the G-square based strength statistic, but also an improved statistic for detecting and comparing the strengths of deferent associations of any two or more sets of multivariate variables, moreover, this new strength statistic can also be tested by G2.
Singular point detection algorithm based on the transition line of the fingerprint orientation image
CSIR Research Space (South Africa)
Mathekga, ME
2009-11-01
Full Text Available A new algorithm for identifying and locating singular points on a fingerprint image is presented. This algorithm is based on properties of the fingerprint orientation image, including a feature defined as a transition line. The transition line...
Misra, Avijit; Biswas, Anindya; Pati, Arun K; Sen De, Aditi; Sen, Ujjwal
2015-05-01
Quantum discord is a measure of quantum correlations beyond the entanglement-separability paradigm. It is conceptualized by using the von Neumann entropy as a measure of disorder. We introduce a class of quantum correlation measures as differences between total and classical correlations, in a shared quantum state, in terms of the sandwiched relative Rényi and Tsallis entropies. We compare our results with those obtained by using the traditional relative entropies. We find that the measures satisfy all the plausible axioms for quantum correlations. We evaluate the measures for shared pure as well as paradigmatic classes of mixed states. We show that the measures can faithfully detect the quantum critical point in the transverse quantum Ising model and find that they can be used to remove an unquieting feature of nearest-neighbor quantum discord in this respect. Furthermore, the measures provide better finite-size scaling exponents of the quantum critical point than the ones for other known order parameters, including entanglement and information-theoretic measures of quantum correlations.
Occupational correlates of smoking among urban transit operators: A prospective study
Directory of Open Access Journals (Sweden)
Banerjee Aniruddha
2007-12-01
Full Text Available Abstract Background Workers in blue-collar and service occupations smoke at higher rates than workers in white-collar and professional occupations. Occupational stress may explain some of the occupational class differences in smoking and quitting behavior. The purpose of this study is to investigate the contribution of occupational factors to smoking behavior over a ten year period among a multiethnic cohort of urban transit operators, while accounting for demographic factors and alcohol. Methods The sample consists of 654 San Francisco Municipal Railway (MUNI transit operators who participated in two occupational health studies and biennial medical examinations during 1983–85 and 1993–95. Workers who had initiated, increased, or maintained their smoking over the ten year period were compared to workers who remained non-smokers. Occupational factors included self-rated frequency of job problems (e.g., difficulties with equipment, passengers, traffic, job burnout (i.e., the emotional exhaustion subscale of the Maslach Burnout Inventory, time needed to unwind after work, and years employed as a transit operator. A series of logistic regression models were developed to estimate the contribution of occupational factors to smoking behavior over time. Results Approximately 35% of the workers increased, initiated, or maintained their smoking over the ten-year period. Frequency of job problems was significantly associated with likelihood of smoking increase, initiation, or maintenance (OR = 1.30; 95% CI 1.09, 1.55. Black operators were significantly more likely to have smoked over the ten-year period compared to operators in other racial/ethnic groups. Conclusion Understanding the role of work-related stress vis-à-vis smoking behavior is of critical importance for crafting workplace smoking prevention and cessation interventions that are applicable to blue-collar work settings, and for developing policies that mitigate occupational stress.
Institute of Scientific and Technical Information of China (English)
Long Fei; Du Lu-Chun; Mei Dong-Cheng
2009-01-01
The nonequilibrium phase transition and the symmetry revival induced by time delay in a bistable system are investigated. The stationary probability distribution function (SPDF) of the bistable system with time delay and correlated noises are calculated by an analytical method and stochastic simulation respectively. The analytical and simulative results indicate that: (1) There is a certain value of λ(λ denotes the strength of correlations between the multiplicative and additive noises) to make the SPDF symmetric under some time delay; however, above or below the given value, the symmetry will be broken; (2) With the monotonic change of λ, the unimodal peak structure of SPDF becomes bimodal at the beginning, then it becomes unimodal again; this means that there is a reentrance phenomenon in the process; (3) There is a critical value of delay time, which makes the lower peak of SPDF equal to the higher one under the critical condition. This means that the symmetry revival phenomenon emerges.
Transitional discharge based on therapeutic relationships: state of the art.
Forchuk, Cheryl; Reynolds, William; Sharkey, Siobhan; Martin, Mary-Lou; Jensen, Elsabeth
2007-04-01
The Transitional Discharge Model (TDM) has been used to facilitate effective discharge from psychiatric hospital to community. A summary of the research to date on TDM is given. The model is based on the provision of therapeutic relationships to provide a safety net throughout the discharge and community reintegration processes. These relationships include both staff and peer involvement; hospital inpatient staff continue to remain involved with the client until a therapeutic relationship is established with a community care provider, and peer support is offered from a former consumer of mental health services who is currently living in the community. Studies found that the TDM facilitates increased discharge rates, lower readmission rates, and cost savings--making it a collaborative, cost-effective method of providing quality patient care and positive health care outcomes. The TDM Plan of Research is presented and reflects the collaboration between stakeholders and the integration of consumer advocacy, clinical practice, education, policy, and research in various countries.
Simulation of transition radiation based beam imaging from tilted targets
Sukhikh, L. G.; Kube, G.; Potylitsyn, A. P.
2017-03-01
Transverse beam profile diagnostics in linear electron accelerators is usually based on direct imaging of a beam spot via visible transition radiation. In this case the fundamental resolution limit is determined by radiation diffraction in the optical system. A method to measure beam sizes beyond the diffraction limit is to perform imaging dominated by a single-particle function (SPF), i.e. when the recorded image is dominated not by the transverse beam profile but by the image function of a point source (single electron). Knowledge of the SPF for an experimental setup allows one to extract the transverse beam size from an SPF dominated image. This paper presents an approach that allows one to calculate two-dimensional SPF dominated beam images, taking into account the target inclination angle and the depth-of-field effect. In conclusion, a simple fit function for beam size determination in the case under consideration is proposed and its applicability is tested under various conditions.
Quantum-based Atomistic Simulation of Transition Metals
Energy Technology Data Exchange (ETDEWEB)
Moriarty, J A; Benedict, L X; Glosli, J N; Hood, R Q; Orlikowski, D A; Patel, M V; Soderlind, P; Streitz, F H; Tang, M; Yang, L H
2005-08-29
First-principles generalized pseudopotential theory (GPT) provides a fundamental basis for transferable multi-ion interatomic potentials in d-electron transition metals within density-functional quantum mechanics. In mid-period bcc metals, where multi-ion angular forces are important to structural properties, simplified model GPT or MGPT potentials have been developed based on canonical d bands to allow analytic forms and large-scale atomistic simulations. Robust, advanced-generation MGPT potentials have now been obtained for Ta and Mo and successfully applied to a wide range of structural, thermodynamic, defect and mechanical properties at both ambient and extreme conditions of pressure and temperature. Recent algorithm improvements have also led to a more general matrix representation of MGPT beyond canonical bands allowing increased accuracy and extension to f-electron actinide metals, an order of magnitude increase in computational speed, and the current development of temperature-dependent potentials.
Energy Technology Data Exchange (ETDEWEB)
Fukushima, Noboru, E-mail: noboru.fukushima@gmail.com [Motomachi 13-23, Sanjo, Niigata 955-0072 (Japan)
2011-02-18
Renormalization of non-magnetic and magnetic impurities due to electron double-occupancy prohibition is derived analytically by an improved Gutzwiller approximation. Non-magnetic impurities are effectively weakened by the same renormalization factor as that for the hopping amplitude, whereas magnetic impurities are strengthened by the square root of the spin-exchange renormalization factor, in contrast to results by the conventional Gutzwiller approximation. We demonstrate it by showing that transition matrix elements of number operators between assumed excited states and between an assumed ground state and excited states are renormalized differently than diagonal matrix elements. Deviation from such simple renormalization with a factor is also discussed. In addition, as a related calculation, we correct an error in treatment of the renormalization of charge interaction in the literature. Namely, terms from the second order of the transition matrix elements are strongly suppressed. Since all these results do not depend on the signs of impurity potential or the charge interaction parameter, they are valid both in attractive and repulsive cases.
Infrared study of the magnetostructural phase transition in correlated CrN
Ebad-Allah, J.; Kugelmann, B.; Rivadulla, F.; Kuntscher, C. A.
2016-11-01
We report on the pressure and temperature dependence of the electronic and vibrational properties of polycrystalline CrN studied by optical transmission and reflection measurements over the frequency range 0.012-2.48 eV. The optical conductivity spectrum of CrN at ambient conditions shows a phonon mode at ≈55 meV with a shoulder at ≈69 meV , a pronounced midinfrared absorption band centered at 123 ±2 meV , and a high-energy absorption band at ≈1.5 eV . The absorption bands are discussed in terms of the charge-transfer insulator picture. Following the reflectance spectrum with increasing pressure, the activation of an additional phonon mode above 0.6 GPa indicates the occurrence of a pressure-induced structural phase transition. Furthermore, the absorption spectrum exhibits significant changes in the far-infrared range with decreasing temperature: The phonon mode shows a sudden broadening followed by a splitting below 270 K. These changes observed under pressure or while cooling down can be associated with the magnetostructural phase transition reported previously.
Long-term visual tracking based on correlation filters
Wei, Quanlu; Lao, Songyang; Bai, Liang
2017-03-01
In order to accomplish the long term visual tracking task in complex scenes, solve problems of scale variation, appearance variation and tracking failure, a long term tracking algorithm is given based on the framework of collaborative correlation tracking. Firstly, we integrate several powerful features to boost the represent ability based on the kernel correlation filter, and extend the filter by embedding a scale factor into the kernelized matrix to handle the scale variation. Then, we use the Peak-Sidelobe Ratio to decide whether the object is tracked successfully, and a CUR filter for re-detection the object in case of tracking failure is learnt with random sampling. Corresponding experiment is performed on 17 challenging benchmark video sequences. Compared with the 8 existing state-of-the-art algorithms based on discriminative learning method, the results show that the proposed algorithm improves the tracking performance on several indexes, and is robust to complex scenes for long term visual tracking.
Combining Correlation-Based and Reward-Based Learning in Neural Control for Policy Improvement
DEFF Research Database (Denmark)
Manoonpong, Poramate; Kolodziejski, Christoph; Wörgötter, Florentin
2013-01-01
associations. Based on these biological findings, we propose a new learning model to achieve successful control policies for artificial systems. This model combines correlation-based learning using input correlation learning (ICO learning) and reward-based learning using continuous actor–critic reinforcement...
Institute of Scientific and Technical Information of China (English)
Reza; Taghavi; Z.; Mahmood; Salary; Amir; Kolaei
2009-01-01
This article presents a linear eddy-viscosity turbulence model for predicting bypass and natural transition in boundary layers by using Reynolds-averaged Navier-Stokes (RANS) equations. The model includes three transport equations, separately, to compute laminar kinetic energy, turbulent kinetic energy, and dissipation rate in a flow field. It needs neither correlations of intermittency factors nor knowledge of the transition onset. Two transition tests are carried out: flat plate boundary layer under zero ...
GPU Based Software Correlators - Perspectives for VLBI2010
Hobiger, Thomas; Kimura, Moritaka; Takefuji, Kazuhiro; Oyama, Tomoaki; Koyama, Yasuhiro; Kondo, Tetsuro; Gotoh, Tadahiro; Amagai, Jun
2010-01-01
Caused by historical separation and driven by the requirements of the PC gaming industry, Graphics Processing Units (GPUs) have evolved to massive parallel processing systems which entered the area of non-graphic related applications. Although a single processing core on the GPU is much slower and provides less functionality than its counterpart on the CPU, the huge number of these small processing entities outperforms the classical processors when the application can be parallelized. Thus, in recent years various radio astronomical projects have started to make use of this technology either to realize the correlator on this platform or to establish the post-processing pipeline with GPUs. Therefore, the feasibility of GPUs as a choice for a VLBI correlator is being investigated, including pros and cons of this technology. Additionally, a GPU based software correlator will be reviewed with respect to energy consumption/GFlop/sec and cost/GFlop/sec.
Correlates of gender and achievement in introductory algebra based physics
Smith, Rachel Clara
The field of physics is heavily male dominated in America. Thus, half of the population of our country is underrepresented and underserved. The identification of factors that contribute to gender disparity in physics is necessary for educators to address the individual needs of students, and, in particular, the separate and specific needs of female students. In an effort to determine if any correlations could be established or strengthened between sex, gender identity, social network, algebra skill, scientific reasoning ability, and/or student attitude, a study was performed on a group of 82 students in an introductory algebra based physics course. The subjects each filled out a survey at the beginning of the semester of their first semester of algebra based physics. They filled out another survey at the end of that same semester. These surveys included physics content pretests and posttests, as well as questions about the students' habits, attitudes, and social networks. Correlates of posttest score were identified, in order of significance, as pretest score, emphasis on conceptual learning, preference for male friends, number of siblings (negatively correlated), motivation in physics, algebra score, and parents' combined education level. Number of siblings was also found to negatively correlate with, in order of significance, gender identity, preference for male friends, emphasis on conceptual learning, and motivation in physics. Preference for male friends was found to correlate with, in order of significance, emphasis on conceptual learning, gender identity, and algebra score. Also, gender identity was found to correlate with emphasis on conceptual learning, the strongest predictor of posttest score other than pretest score.
DEFF Research Database (Denmark)
von Essen, C.; Cellone, S.; Mallonn, M.
2016-01-01
the observing time at hand carrying out such follow-ups, or if the use of medium-to-low quality transit light curves, combined with current standard techniques of data analysis, could be playing a main role against exoplanetary search via TTVs. The purpose of this work is to investigate to what extent ground...... we attempt to reproduce, by means of physically and empirically motivated relationships, the effects caused by the Earth's atmosphere and the instrumental setup on the synthetic light curves. Therefore, the synthetic data present different photometric quality and transit coverage. In addition, we...... introduced a perturbation in the mid-transit times of the hot Jupiter, caused by an Earth-sized planet in a 3:2 mean motion resonance. Analyzing the synthetic light curves produced after certain epochs, we attempt to recover the synthetically added TTV signal by means of usual primary transit fitting...
Liu, Qingqing; Yu, Xiaohui; Wang, Xiancheng; Deng, Zheng; Lv, Yuxi; Zhu, Jinlong; Zhang, Sijia; Liu, Haozhe; Yang, Wenge; Wang, Lin; Mao, Hokwang; Shen, Guoyin; Lu, Zhong-Yi; Ren, Yang; Chen, Zhiqiang; Lin, Zhijun; Zhao, Yusheng; Jin, Changqing
2011-05-25
The effect of pressure on the crystalline structure and superconducting transition temperature (T(c)) of the 111-type Na(1-x)FeAs system using in situ high-pressure synchrotron X-ray powder diffraction and diamond anvil cell techniques is studied. A pressure-induced tetragonal to tetragonal isostructural phase transition was found. The systematic evolution of the FeAs(4) tetrahedron as a function of pressure based on Rietveld refinements on the powder X-ray diffraction patterns was obtained. The nonmonotonic T(c)(P) behavior of Na(1-x)FeAs is found to correlate with the anomalies of the distance between the anion (As) and the iron layer as well as the bond angle of As-Fe-As for the two tetragonal phases. This behavior provides the key structural information in understanding the origin of the pressure dependence of T(c) for 111-type iron pnictide superconductors. A pressure-induced structural phase transition is also observed at 20 GPa.
Transition metal implanted ZnO. A correlation between structure and magnetism
Energy Technology Data Exchange (ETDEWEB)
Zhou, Shengqiang
2008-07-01
Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors question the origin of this ferromagnetism, i.e. if the observed ferromagnetism stems from ferromagnetic precipitates rather than from carriermediated magnetic coupling of ionic impurities, as required for a diluted magnetic semiconductor. In this thesis, this question will be answered for transition-metal implanted ZnO single crystals. Magnetic secondary phases, namely metallic Fe, Co and Ni nanocrystals, are formed inside ZnO. They are - although difficult to detect by common approaches of structural analysis - responsible for the observed ferromagnetism. Particularly Co and Ni nanocrystals are crystallographically oriented with respect to the ZnO matrix. Their structure phase transformation and corresponding evolution of magnetic properties upon annealing have been established. Finally, an approach, pre-annealing ZnO crystals at high temperature before implantation, has been demonstrated to sufficiently suppress the formation of metallic secondary phases. (orig.)
Evolution of leaf form correlates with tropical–temperate transitions in Viburnum (Adoxaceae)
Schmerler, Samuel B.; Clement, Wendy L.; Beaulieu, Jeremy M.; Chatelet, David S.; Sack, Lawren; Donoghue, Michael J.; Edwards, Erika J.
2012-01-01
Strong latitudinal patterns in leaf form are well documented in floristic comparisons and palaeobotanical studies. However, there is little agreement about their functional significance; in fact, it is still unknown to what degree these patterns were generated by repeated evolutionary adaptation. We analysed leaf form in the woody angiosperm clade Viburnum (Adoxaceae) and document evolutionarily correlated shifts in leafing habit, leaf margin morphology, leaf shape and climate. Multiple independent shifts between tropical and temperate forest habitats have repeatedly been accompanied by a change between evergreen, elliptical leaves with entire margins and deciduous, more rounded leaves with toothed or lobed margins. These consistent shifts in Viburnum support repeated evolutionary adaptation as a major determinant of the global correlation between leaf form and mean annual temperature. Our results provide a new theoretical grounding for the inference of past climates using fossil leaf assemblages. PMID:22810426
1988-01-01
Cell surface ABO(H) antigenicity of superficial bladder tumours was assessed by the indirect immunoperoxidase test in 49 patients. Good correlation was obtained between surface antigenicity of tumours and the results of urine cytology. Malignant cells were detected cytologically in 22(56%) of cases with ABO(H) antigen negative tumours which are known to behave more aggressively than ABO(H) antigen positive ones. In contrast, malignant cells were found in the urine cytology of only one (10%) o...
DAS, G.; Glashan, R W
1988-01-01
Cell surface ABO(H) antigenicity of superficial bladder tumours was assessed by the indirect immunoperoxidase test in 49 patients. Good correlation was obtained between surface antigenicity of tumours and the results of urine cytology. Malignant cells were detected cytologically in 22(56%) of cases with ABO(H) antigen negative tumours which are known to behave more aggressively than ABO(H) antigen positive ones. In contrast, malignant cells were found in the urine cytology of only one (10%) o...
An edge-adaptive demosaicking method based on image correlation
Institute of Scientific and Technical Information of China (English)
贾晓芬; 赵佰亭; 周孟然; 陈兆权
2015-01-01
To reduce the cost, size and complexity, a consumer digital camera usually uses a single sensor overlaid with a color filter array (CFA) to sample one of the red−green−blue primary color values, and uses demosaicking algorithm to estimate the missing color values at each pixel. A novel image correlation and support vector machine (SVM) based edge-adaptive algorithm was proposed, which can reduce edge artifacts and false color artifacts, effectively. Firstly, image pixels were separated into edge region and smooth region with an edge detection algorithm. Then, a hybrid approach switching between a simple demosaicking algorithm on the smooth region and SVM based demosaicking algorithm on the edge region was performed. Image spatial and spectral correlations were employed to create middle planes for the interpolation. Experimental result shows that the proposed approach produced visually pleasing full-color result images and obtained higher CPSNR and smaller S-CIELAB *abDE than other conventional demosaicking algorithms.
Thermal Phase Transitions of Strongly Correlated Bosons with Spin-Orbit Coupling
Hickey, Ciarán; Paramekanti, Arun
2014-12-01
Experiments on ultracold atoms have started to explore lattice effects and thermal fluctuations for two-component bosons with spin-orbit coupling (SOC). Motivated by this, we derive and study a t J model for lattice bosons with equal Rashba-Dresselhaus SOC and strong Hubbard repulsion in a uniform Zeeman magnetic field. Using the Gutzwiller ansatz, we find strongly correlated ground states with stripe superfluid (SF) order. We formulate a finite temperature generalization of the Gutzwiller method, and show that thermal fluctuations in the doped Mott insulator drive a two-step melting of the stripe SF, revealing a wide regime of a stripe normal fluid.
Li, Qingfeng; Steinheimer, Jan; Petersen, Hannah; Bleicher, Marcus; Stöcker, Horst
2009-04-01
A systematic study of HBT radii of pions, produced in heavy ion collisions in the intermediate energy regime (SPS), from an integrated (3 + 1)d Boltzmann + hydrodynamics approach is presented. The calculations in this hybrid approach, incorporating an hydrodynamic stage into the Ultra-relativistic Quantum Molecular Dynamics transport model, allow for a comparison of different equations of state retaining the same initial conditions and final freeze-out. The results are also compared to the pure cascade transport model calculations in the context of the available data. Furthermore, the effect of different treatments of the hydrodynamic freeze-out procedure on the HBT radii are investigated. It is found that the HBT radii are essentially insensitive to the details of the freeze-out prescription as long as the final hadronic interactions in the cascade are taken into account. The HBT radii RL and RO and the RO /RS ratio are sensitive to the EoS that is employed during the hydrodynamic evolution. We conclude that the increased lifetime in case of a phase transition to a QGP (via a Bag Model equation of state) is not supported by the available data.
Energy Technology Data Exchange (ETDEWEB)
Li Qingfeng [School of Science, Huzhou Teachers College, Huzhou 313000 (China); Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe-Universitaet, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany)], E-mail: liqf@fias.uni-frankfurt.de; Steinheimer, Jan [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)], E-mail: steinheimer@th.physik.uni-frankfurt.de; Petersen, Hannah [Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe-Universitaet, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany); Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)], E-mail: petersen@th.physik.uni-frankfurt.de; Bleicher, Marcus [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)], E-mail: bleicher@th.physik.uni-frankfurt.de; Stoecker, Horst [Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe-Universitaet, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany); Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Gesellschaft fuer Schwerionenforschung (GSI), Planckstr. 1, D-64291 Darmstadt (Germany)], E-mail: h.stoecker@gsi.de
2009-04-13
A systematic study of HBT radii of pions, produced in heavy ion collisions in the intermediate energy regime (SPS), from an integrated (3+1)d Boltzmann + hydrodynamics approach is presented. The calculations in this hybrid approach, incorporating an hydrodynamic stage into the Ultra-relativistic Quantum Molecular Dynamics transport model, allow for a comparison of different equations of state retaining the same initial conditions and final freeze-out. The results are also compared to the pure cascade transport model calculations in the context of the available data. Furthermore, the effect of different treatments of the hydrodynamic freeze-out procedure on the HBT radii are investigated. It is found that the HBT radii are essentially insensitive to the details of the freeze-out prescription as long as the final hadronic interactions in the cascade are taken into account. The HBT radii R{sub L} and R{sub O} and the R{sub O}/R{sub S} ratio are sensitive to the EoS that is employed during the hydrodynamic evolution. We conclude that the increased lifetime in case of a phase transition to a QGP (via a Bag Model equation of state) is not supported by the available data.
Peng, Chung-Kan; Wu, Shu-Fen; Yang, Shih-Hsing; Hsieh, Chuan-Fa; Huang, Chung-Chih; Huang, Yuh-Chin T; Wu, Chin-Pyng
2017-06-01
We have previously shown in patients receiving adaptive support ventilation (ASV) that there existed a Transition %MinVol (TMV%) where the patient's work of breathing began to reduce. In this study, we tested the hypothesis that higher TMV% would be associated with poorer outcome in patients with acute respiratory failure. In this prospective observational study, we recruited patients with acute respiratory failure on ASV between December 2012 and September 2013 in a mixed ICU. The TMV% was determined by adjusting % MinVol until mandatory respiratory frequency was between 0 and 1breath/min. TMV% was measured on the first two days of mechanical ventilation. A total of 337 patients (age: 70±16years) were recruited. In patients whose TMV% increased between Day 1 and Day 2, aOR for mortality was 7.0 (95%CI=2.7-18.3, pTMV% decreased. In patients whose TMV% was unchanged between Day 1 and Day2, aOR for mortality was 3.91 (95%CI=1.80-8.22, pTMV% from Day 1 to Day 2 was associated with higher risk of in-hospital death. Copyright © 2017 Elsevier Inc. All rights reserved.
Soil respiration across a permafrost transition zone: spatial structure and environmental correlates
Energy Technology Data Exchange (ETDEWEB)
Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Benjamin; Crump, Alex R.; Chen, Xingyuan; Hess, Nancy J.
2017-09-28
Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active layer depths greater than 140cm. We also find that within each season tree basal area is a dominant driver of soil respiration regardless of spatial scale, but only in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation and scaling of soil respiration—in our boreal system—are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally-stable features such as tree stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Combining such an approach with broader knowledge of thresholding behavior—here related to active layer depth—would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.
Sciarretta, G; Fagioli, G; Furno, A; Vicini, G; Cecchetti, L; Grigolo, B; Verri, A; Malaguti, P
1987-01-01
The purpose of this study was to evaluate whether bile acid malabsorption assessed by the 75SeHCAT test, had a pathogenetic role in functional chronic diarrhoea and to ascertain whether the small bowel transit time (SBTT) could be correlated with the 75SeHCAT test results. The test was based on the counting of the abdominal retention of a 75-selenium labelled homotaurocholic acid. The 75SeHCAT test was carried out in a control group of 23 healthy adults and in 46 patients, 38 of whom were suffering from irritable bowel syndrome (IBS) of diarrhoeic form and eight patients who had undergone cholecystectomy and were suffering from chronic diarrhoea. Faecal bile acid loss was determined in nine patients, and in 14, serum bile acid increase after a standard meal was measured. In 17, SBTT was studied by hydrogen breath test after lactulose administration (21 g in 300 ml water). In 15 patients, choledochocaecal transit time was estimated by Tc99m-HIDA (111 MBq) cholescintigraphy. In 20 of 46 subjects, 75SeHCAT retention was below normal level, and in 19 cholestyramine administration relieved diarrhoea. 75SeHCAT results were related to faecal bile acid loss, while no correlation was found with serum bile acids and SBTT. The data suggest a possible wider use of the 75SeHCAT test in chronic diarrhoea to estimate bile acid malabsorption in irritable bowel syndrome, diarrhoeic form, and provide an effective treatment. In our patients small bowel transit velocity does not seem to be a pathogenetic factor of bile acid malabsorption. PMID:3666565
Directory of Open Access Journals (Sweden)
Dino P McMahon
Full Text Available A comprehensive model of evolution requires an understanding of the relationship between selection at the molecular and phenotypic level. We investigate this in Strepsiptera, an order of endoparasitic insects whose evolutionary biology is poorly studied. We present the first molecular phylogeny of Strepsiptera, and use this as a framework to investigate the association between parasitism and molecular evolution. We find evidence of a significant burst in the rate of molecular evolution in the early history of Strepsiptera. The evolution of morphological traits linked to parasitism is significantly correlated with the pattern in molecular rate. The correlated burst in genotypic-phenotypic evolution precedes the main phase of strepsipteran diversification, which is characterised by the return to a low and even molecular rate, and a period of relative morphological stability. These findings suggest that the transition to endoparasitism led to relaxation of selective constraint in the strepsipteran genome. Our results indicate that a parasitic lifestyle can affect the rate of molecular evolution, although other causal life-history traits correlated with parasitism may also play an important role.
Directory of Open Access Journals (Sweden)
Amelia Asbe
Full Text Available Angiosperm flowers are usually determinate structures that may produce seeds. In some species, flowers can revert from committed flower development back to an earlier developmental phase in a process called floral reversion. The allopolyploid Arabidopsis suecica displays photoperiod-dependent floral reversion in a subset of its flowers, yet little is known about the environmental conditions enhancing this phenotype, or the morphological processes leading to reversion. We have used light and electron microscopy to further describe this phenomenon. Additionally, we have further studied the phenology of flowering and floral reversion in A. suecica. In this study we confirm and expand upon our previous findings that floral reversion in the allopolyploid A. suecica is photoperiod-dependent, and show that its frequency is correlated with the timing for the onset of flowering. Our results also suggest that floral reversion in A. suecica displays natural variation in its penetrance between geographic populations of A. suecica.
Optimisation of timetable-based, stochastic transit assignment models based on MSA
DEFF Research Database (Denmark)
Nielsen, Otto Anker; Frederiksen, Rasmus Dyhr
2006-01-01
Public transport assignment models have increased in complexity in order to describe passengers' route choices as detailed and correctly as possible. Important trends in the development are (1) timetable-based assignment, (2) inclusion of feeder modes, (3) use of stochastic components to describe...... (CRM), such a large-scale transit assignment model was developed and estimated. The Stochastic User Equilibrium problem was solved by the Method of Successive Averages (MSA). However, the model suffered from very large calculation times. The paper focuses on how to optimise transit assignment models...
Correlation-based temperature and emissivity separation algorithm
Institute of Scientific and Technical Information of China (English)
CHENG Jie; LIU QinHuo; LI XiaoWen; XIAO Qing; LIU Qiang; DU YongMing
2008-01-01
Based on analyzing the relationship between the atmospheric downward radiance and surface emissivity, this paper proposes a correlation criterion to optimize surface temperature during the process of temperature and emissivity separation from thermal infrared hyperspectral data, and puts forward the correlation-based temperature and emissivity separation algorithm (CBTES). The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity to optimize surface temperature, and obtains surface emissivity with this temperature. The accuracy of CBTES was evaluated by the simulated thermal infrared hyperspectral data. The simulated results show that the CBTES can achieve high accuracy of temperature and emissivity inversion. CBTES has been compared with the iterative spectrally smooth temperature/emissivity separation (ISSTES), and the comparison results show that they have relative accuracy. Besides, CBTES is insensitive to the instrumental random noise and the change of atmospheric downward radiance during the measurements. As regards the nonisothermal pixel, its radiometric temperature changes slowly with the wavenumber when its emissivity is defined as r-emissivity. The CBTES can be used to derive the equivalent temperature of nonisothermal pixel in a narrow spectral region when we assumed that the radiometric temperature is invariable in the narrow spectral region. The derived equivalent temperatures in multi-spectral regions in 714-250cm-1 can characterize the change trend of nonisothermal pixel's radiometric temperature.
Correlation-based temperature and emissivity separation algorithm
Institute of Scientific and Technical Information of China (English)
2008-01-01
Based on analyzing the relationship between the atmospheric downward radiance and surface emis- sivity, this paper proposes a correlation criterion to optimize surface temperature during the process of temperature and emissivity separation from thermal infrared hyperspectral data, and puts forward the correlation-based temperature and emissivity separation algorithm (CBTES). The algorithm uses the correlation between the atmospheric downward radiance and surface emissivity to optimize surface temperature, and obtains surface emissivity with this temperature. The accuracy of CBTES was evalu- ated by the simulated thermal infrared hyperspectral data. The simulated results show that the CBTES can achieve high accuracy of temperature and emissivity inversion. CBTES has been compared with the iterative spectrally smooth temperature/emissivity separation (ISSTES), and the comparison results show that they have relative accuracy. Besides, CBTES is insensitive to the instrumental random noise and the change of atmospheric downward radiance during the measurements. As regards the noniso- thermal pixel, its radiometric temperature changes slowly with the wavenumber when its emissivity is defined as r-emissivity. The CBTES can be used to derive the equivalent temperature of nonisothermal pixel in a narrow spectral region when we assumed that the radiometric temperature is invariable in the narrow spectral region. The derived equivalent temperatures in multi-spectral regions in 714―1250 cm?1 can characterize the change trend of nonisothermal pixel’s radiometric temperature.
Directory of Open Access Journals (Sweden)
Xin Li
2016-08-01
Full Text Available This paper employs a canonical correlation analysis method to quantify the linkage between urban rail transit station demand and the surrounding land-use patterns. It is used to identify key land use variables by evaluating their degrees of contribution to the rail transit station demand. A full month of IC card data and detailed regulatory land use plan from Chongqing, China are collected for model development and validation. The proposed model contributes to offering the capability of targeting key land use patterns and associating them with rail transit station boarding and alighting demand simultaneously. The proposed model can reveal underlying rules between rail transit station demand and land use variables and can be used to evaluate the Transit Oriented Development (TOD plans to improve land use and transit operational efficiency.
Spike Detection Based on Normalized Correlation with Automatic Template Generation
Directory of Open Access Journals (Sweden)
Wen-Jyi Hwang
2014-06-01
Full Text Available A novel feedback-based spike detection algorithm for noisy spike trains is presented in this paper. It uses the information extracted from the results of spike classification for the enhancement of spike detection. The algorithm performs template matching for spike detection by a normalized correlator. The detected spikes are then sorted by the OSortalgorithm. The mean of spikes of each cluster produced by the OSort algorithm is used as the template of the normalized correlator for subsequent detection. The automatic generation and updating of templates enhance the robustness of the spike detection to input trains with various spike waveforms and noise levels. Experimental results show that the proposed algorithm operating in conjunction with OSort is an efficient design for attaining high detection and classification accuracy for spike sorting.
Robust Reservoir Generation by Correlation-Based Learning
Directory of Open Access Journals (Sweden)
Tadashi Yamazaki
2009-01-01
Full Text Available Reservoir computing (RC is a new framework for neural computation. A reservoir is usually a recurrent neural network with fixed random connections. In this article, we propose an RC model in which the connections in the reservoir are modifiable. Specifically, we consider correlation-based learning (CBL, which modifies the connection weight between a given pair of neurons according to the correlation in their activities. We demonstrate that CBL enables the reservoir to reproduce almost the same spatiotemporal activity patterns in response to an identical input stimulus in the presence of noise. This result suggests that CBL enhances the robustness in the generation of the spatiotemporal activity pattern against noise in input signals. We apply our RC model to trace eyeblink conditioning. The reservoir bridged the gap of an interstimulus interval between the conditioned and unconditioned stimuli, and a readout neuron was able to learn and express the timed conditioned response.
Optimization of integer wavelet transforms based on difference correlation structures.
Li, Hongliang; Liu, Guizhong; Zhang, Zhongwei
2005-11-01
In this paper, a novel lifting integer wavelet transform based on difference correlation structure (DCCS-LIWT) is proposed. First, we establish a relationship between the performance of a linear predictor and the difference correlations of an image. The obtained results provide a theoretical foundation for the following construction of the optimal lifting filters. Then, the optimal prediction lifting coefficients in the sense of least-square prediction error are derived. DCCS-LIWT puts heavy emphasis on image inherent dependence. A distinct feature of this method is the use of the variance-normalized autocorrelation function of the difference image to construct a linear predictor and adapt the predictor to varying image sources. The proposed scheme also allows respective calculations of the lifting filters for the horizontal and vertical orientations. Experimental evaluation shows that the proposed method produces better results than the other well-known integer transforms for the lossless image compression.
Simulation of transition radiation based beam imaging from tilted targets
Directory of Open Access Journals (Sweden)
L. G. Sukhikh
2017-03-01
Full Text Available Transverse beam profile diagnostics in linear electron accelerators is usually based on direct imaging of a beam spot via visible transition radiation. In this case the fundamental resolution limit is determined by radiation diffraction in the optical system. A method to measure beam sizes beyond the diffraction limit is to perform imaging dominated by a single-particle function (SPF, i.e. when the recorded image is dominated not by the transverse beam profile but by the image function of a point source (single electron. Knowledge of the SPF for an experimental setup allows one to extract the transverse beam size from an SPF dominated image. This paper presents an approach that allows one to calculate two-dimensional SPF dominated beam images, taking into account the target inclination angle and the depth-of-field effect. In conclusion, a simple fit function for beam size determination in the case under consideration is proposed and its applicability is tested under various conditions.
3D shape measurement with phase correlation based fringe projection
Kühmstedt, Peter; Munckelt, Christoph; Heinze, Matthias; Bräuer-Burchardt, Christian; Notni, Gunther
2007-06-01
Here we propose a method for 3D shape measurement by means of phase correlation based fringe projection in a stereo arrangement. The novelty in the approach is characterized by following features. Correlation between phase values of the images of two cameras is used for the co-ordinate calculation. This work stands in contrast to the sole usage of phase values (phasogrammetry) or classical triangulation (phase values and image co-ordinates - camera raster values) for the determination of the co-ordinates. The method's main advantage is the insensitivity of the 3D-coordinates from the absolute phase values. Thus it prevents errors in the determination of the co-ordinates and improves robustness in areas with interreflections artefacts and inhomogeneous regions of intensity. A technical advantage is the fact that the accuracy of the 3D co-ordinates does not depend on the projection resolution. Thus the achievable quality of the 3D co-ordinates can be selectively improved by the use of high quality camera lenses and can participate in improvements in modern camera technologies. The presented new solution of the stereo based fringe projection with phase correlation makes a flexible, errortolerant realization of measuring systems within different applications like quality control, rapid prototyping, design and CAD/CAM possible. In the paper the phase correlation method will be described in detail. Furthermore, different realizations will be shown, i.e. a mobile system for the measurement of large objects and an endoscopic like system for CAD/CAM in dental industry.
Colón-Ramos, Uriyoán; Pérez-Cardona, Cynthia M; Monge-Rojas, Rafael
2013-11-01
To identify socio-demographic, behavioral, and health-related correlates of food preferences in Puerto Rico that will help determine Caribbean-region populations vulnerable to nutrition transition. Data from a cross-sectional study of a representative sample of 858 adults residing in the San Juan Metropolitan Area of Puerto Rico were analyzed. Multivariable ordinal logistic regressions were used to model the frequency of consumption of 1) fruits and vegetables, 2) tubers/starchy root vegetables, 3) fried foods, and 4) Western-style fast foods as a function of socio-demographic, behavioral, and health-related characteristics. Higher frequency of consumption of fruits and vegetables was associated with being physically active and older and having a medium to high level of education, whereas intake of tubers was associated with being older, having a low income, not using government insurance, and having elevated levels of triglycerides. Frequency of consumption of fast food was associated with younger age, higher income, 12-15 years of formal education, and a higher body mass index (BMI), whereas frequency of consumption of fried food was associated with being younger and male, not being a smoker, and having elevated levels of fasting blood glucose. The results indicate a nutrition transition in Puerto Rico with health consequences for the Caribbean region. The characteristics of this nutrition transition seem to be determined by income, education, and age, but may also be dictated by access to various food groups. These results set the stage for needed investigation of environmental and individual-level factors that could shape patterns in food consumption.
Szolnoki, Attila
2013-01-01
Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionary advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding and punishment, a fourth strategy combining the later two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet despite the high complexity of solution...
Tao, Kai; Grand, Stephen P.; Niu, Fenglin
2017-09-01
In seismic full-waveform inversion (FWI), the choice of misfit function determines what information in data is used and ultimately affects the resolution of the inverted images of the Earth's structure. Misfit functions based on traveltime have been successfully applied in global and regional tomographic studies. However, wave propagation through the upper mantle results in multiple phases arriving at a given receiver in a narrow time interval resulting in complicated waveforms that evolve with distance. To extract waveform information as well as traveltime, we use a misfit function based on the normalized correlation coefficient (CC). This misfit function is able to capture the waveform complexities in both phase and relative amplitude within the measurement window. It is also insensitive to absolute amplitude differences between modeled and recorded data, which avoids problems due to uncertainties in source magnitude, radiation pattern, receiver site effects or even miscalibrated instruments. These features make the misfit function based on normalized CC a good candidate to achieve high-resolution images of complex geological structures when interfering phases coexist in the measurement window, such as triplication waveforms. From synthetic tests, we show the advantages of this misfit function over the cross-correlation traveltime misfit function. Preliminary inversion of data from an earthquake in Northeast China images a sharper and stronger amplitude slab stagnant in the middle of the transition zone than FWI of cross-correlation traveltime.
Faiez, Reza; Rezaei, Yazdan
2016-12-01
In this paper, steady-oscillatory transition of the convective flow in a Czochralski (Cz) growth system was numerically studied. In this configuration, rapid variations in density across narrow region of the flow in the vicinity of the crystallization front leads to an unstable stratification of the flow in this region. Time-dependent, finite volume method calculation of the momentum and heat transport equations shows that an instability mechanism, giving rise to the formation of cold plumes beneath the phase boundary, might be associated with an irreversible change in the convexity of the front. Dynamics of the crystallization front was found to be correlated with the periodic oscillation of the flow. It was shown that the interface inversion process occurs at a critical Reynolds number significantly (˜25%) lower than that predicted by the steady-state Cz-oxide model analysis. Consistently, the time-averaged maximum value of stream function was found to be larger than its corresponding steady-state value. This indicates that the mechanism behind the oscillatory transition of the flow has a positive feedback on the intensity of forced convection flow. These numerical results were attributed to the baroclinic instability mechanism characterized by oscillations of a cold plume appearing at the crystal periphery and descending along the symmetry axis. The time period of oscillations was found to be considerably (30-40%) decreases and, simultaneously, the inclination angle of isopycnals increases (˜48%) at a critical rotation rate of the crystal for which the interface inversion occurs.
Energy Technology Data Exchange (ETDEWEB)
Feely, L.C.; Davis, S.S.
1989-04-01
Two controlled-release hydroxypropylmethylcellulose (HPMC) matrix formulations, a single-unit and a multiple-unit system, have been evaluated in human volunteers. Both formulations contained the sympathomimetic drug phenylpropanolamine hydrochloride and each was radiolabeled with /sup 111/Inbound Amberlite IR 120 ion-exchange resin. The formulations were administered to each of six healthy male volunteers and gastrointestinal (GI) transit was monitored using a gamma camera. Serum samples were taken at set time intervals and assayed for phenylpropanolamine content, thus allowing blood drug levels to be correlated with the position of the dosage form in the GI tract. The multiple-unit system emptied from the stomach gradually over a period of about 180 min, when administered after a light breakfast, whereas the single-unit dosage forms had extremely variable gastric emptying times (range, 60 to greater than 570 min). However, both formulations provided prolonged phenylpropanolamine blood levels. The differences in the blood profiles obtained with the two formulations were attributed to variations in their in vitro release rates and not to any differences in their GI transit times.
Rubino, V.; Lapusta, N.; Rosakis, A.
2012-12-01
Mapping full-field displacements and strains on the Earth's surface during an earthquake is of paramount importance to enhance our understanding of earthquake mechanics. In this study, the feasibility of such measurements using image correlation methods is investigated in a laboratory earthquake setup. Earthquakes are mimicked in the laboratory by dynamic rupture propagating along an inclined frictional interface formed by two Homalite plates under compression, using the configuration developed by Rosakis and coworkers (e.g., Rosakis et al., 2007). In our study, the interface is partially glued, in order to confine the rupture before it reaches the ends of the specimen. The specimens are painted with a speckle pattern to provide the surface with characteristic features for image matching. Images of the specimens are taken before and after dynamic rupture with a 4 Megapixels resolution CCD camera. The digital images are analyzed with two software packages: VIC-2D (Correlated Solutions Inc.) and COSI-Corr (Leprince et. al, 2007). Both VIC-2D and COSI-Corr are able to characterize the full-field static displacement of a dynamic crack. For example, in a case with secondary mode I cracks, the correlation analysis performed with either software clearly shows (i) the relative displacement (slip) along the frictional interface, (ii) the rupture arrest on the glued boundaries, and (iii) the presence of two wing cracks. The obtained displacement measurements are converted to strains, using de-noising techniques. The digital image correlation method is then used in combination with high-speed photography. We will report our progress on the study of a spontaneously expanding sub-Rayleigh shear crack advancing along an interface containing a patch of favorable heterogeneity, such as a preexisting subcritical crack or a patch with higher prestress. According to the predictions of Liu and Lapusta (2008), intersonic transition and propagation can be achieved in the presence of a
Goodpaster, Jason D; Barnes, Taylor A; Manby, Frederick R; Miller, Thomas F
2012-12-14
Density functional theory (DFT) embedding provides a formally exact framework for interfacing correlated wave-function theory (WFT) methods with lower-level descriptions of electronic structure. Here, we report techniques to improve the accuracy and stability of WFT-in-DFT embedding calculations. In particular, we develop spin-dependent embedding potentials in both restricted and unrestricted orbital formulations to enable WFT-in-DFT embedding for open-shell systems, and develop an orbital-occupation-freezing technique to improve the convergence of optimized effective potential calculations that arise in the evaluation of the embedding potential. The new techniques are demonstrated in applications to the van-der-Waals-bound ethylene-propylene dimer and to the hexa-aquairon(II) transition-metal cation. Calculation of the dissociation curve for the ethylene-propylene dimer reveals that WFT-in-DFT embedding reproduces full CCSD(T) energies to within 0.1 kcal/mol at all distances, eliminating errors in the dispersion interactions due to conventional exchange-correlation (XC) functionals while simultaneously avoiding errors due to subsystem partitioning across covalent bonds. Application of WFT-in-DFT embedding to the calculation of the low-spin/high-spin splitting energy in the hexaaquairon(II) cation reveals that the majority of the dependence on the DFT XC functional can be eliminated by treating only the single transition-metal atom at the WFT level; furthermore, these calculations demonstrate the substantial effects of open-shell contributions to the embedding potential, and they suggest that restricted open-shell WFT-in-DFT embedding provides better accuracy than unrestricted open-shell WFT-in-DFT embedding due to the removal of spin contamination.
Matrix-based concordance correlation coefficient for repeated measures.
Hiriote, Sasiprapa; Chinchilli, Vernon M
2011-09-01
In many clinical studies, Lin's concordance correlation coefficient (CCC) is a common tool to assess the agreement of a continuous response measured by two raters or methods. However, the need for measures of agreement may arise for more complex situations, such as when the responses are measured on more than one occasion by each rater or method. In this work, we propose a new CCC in the presence of repeated measurements, called the matrix-based concordance correlation coefficient (MCCC) based on a matrix norm that possesses the properties needed to characterize the level of agreement between two p× 1 vectors of random variables. It can be shown that the MCCC reduces to Lin's CCC when p= 1. For inference, we propose an estimator for the MCCC based on U-statistics. Furthermore, we derive the asymptotic distribution of the estimator of the MCCC, which is proven to be normal. The simulation studies confirm that overall in terms of accuracy, precision, and coverage probability, the estimator of the MCCC works very well in general cases especially when n is greater than 40. Finally, we use real data from an Asthma Clinical Research Network (ACRN) study and the Penn State Young Women's Health Study for demonstration.
High pressure and microwave based synthesis of transition metal pnictides
Energy Technology Data Exchange (ETDEWEB)
Pobel, Roman Rupert
2016-04-11
The goal of this thesis was to explore the possibilities of synthetic methods that are not very common in current transition metal pnictide research. The substitution of the Ca-site in CaFe{sub 2}As{sub 2} with rare earth elements such as Pr the has been reported to induce superconductivity. However, some inconsistencies in the data suggested a non-intrinsic origin of the observed diamagnetic signal. Furthermore a solubility limit of 13% was found when prepared in an electrical furnace thus leaving a huge part of the physical phase diagram inaccessible. A high pressure/high temperature synthesis was developed to allow access to the whole doping range and an in-depth characterization of this compound was carried out. During the experiments concerning the high pressure synthesis of Ca{sub 1-x}Pr{sub x}Fe{sub 2}As{sub 2} the new ternary iron arsenide CaFe{sub 5}As{sub 3} was identified and classified as a member of the Ca{sub n(n+1)/2}(Fe{sub 1-x}M{sub x}){sub (2+3n)}M'{sub n(n-1)/2}As{sub (n+1)(n+2)/2} (n = 1-3; M =Nb, Pd, Pt; M' = □, Pd, Pt) family. The complete solid solution Ca{sub 1-x}Pr{sub x}Fe{sub 5}As{sub 3} (O ≤ x ≤ 1) was prepared and physically characterized. Furthermore, several useful techniques were developed to aid in future high pressure based investigations of transition metal pnictides. The second part of this thesis concerns a completely different, but equally promising synthetic approach. Microwave based synthesis is a well-established technique in many solution based fields, such as organic, medicinal or nano chemistry. For solid state and materials research several parameters and particularities have to be considered. But when successful, it allows for the reduction of reaction time by several orders of magnitude. It has very rarely been applied in the preparation of pnictides and on1y once in the context of pnictide superconductor research. The possibilities of this method were explored and employed in the preparation of several
Vehicle detection and tracking based on phase-correlation
Institute of Scientific and Technical Information of China (English)
Yi He(何毅); Xin Yang(杨新)
2004-01-01
This paper presents vehicle detection and tracking algorithms based on real-time background (RTB) and phase-correlation (PC) in the video sequence of urban highway with fixed camera. Firstly moving objects are obtained by subtracting RTB from serial images. After classification, PC is used to determine corresponding regions of moving objects between consecutive frames. The problems of vehicles' merging and splitting, sudden stop, and restart are also considered. Experiments show that the method is practical and can realize real-time detection and tracking of vehicles on highway.
Traffic Sign Recognition System based on Cambridge Correlator Image Comparator
J. Turan; L. Ovsenik; T. Harasthy
2012-01-01
Paper presents basic information about application of Optical Correlator (OC), specifically Cambridge Correlator, in system to recognize of traffic sign. Traffic Sign Recognition System consists of three main blocks, Preprocessing, Optical Correlator and Traffic Sign Identification. The Region of Interest (ROI) is defined and chosen in preprocessing block and then goes to Optical Correlator, where is compared with database of Traffic Sign. Output of Optical Correlation is correlation plane, w...
Wei, Shuai; Busch, Ralf; Angell, C Austen
2010-01-01
The glass transition GT is usually thought of as a structural arrest that occurs during the cooling of a liquid, or sometimes a plastic crystal, trapping a metastable state of the system before it can recrystallize to stabler forms1. This phenomenon occurs in liquids of all classes, most recently in bulk metallic glassformers2. Much theoretical interest has been generated by the dynamical heterogeneity observed in cooling of fragile liquids3, 4, and many have suggested that the slow-down is caused by a related increasing correlation length 5-9. Here we report both kinetics and thermodynamics of arrest in a system that disorders while in its ground state, exhibits a large !Cp on arrest (!Cp = Cp,mobile - Cp,arrested), yet clearly is characterized by a correlation length that is decreasing as GT is approached from above. We show that GT kinetics in our system, the disordering superlattice Fe50Co50, satisfy the kinetic criterion for ideally 'strong' glassformers10, and since !Cp behavior through Tg also correlat...
Canonical correlation analysis for gene-based pleiotropy discovery.
Directory of Open Access Journals (Sweden)
Jose A Seoane
2014-10-01
Full Text Available Genome-wide association studies have identified a wealth of genetic variants involved in complex traits and multifactorial diseases. There is now considerable interest in testing variants for association with multiple phenotypes (pleiotropy and for testing multiple variants for association with a single phenotype (gene-based association tests. Such approaches can increase statistical power by combining evidence for association over multiple phenotypes or genetic variants respectively. Canonical Correlation Analysis (CCA measures the correlation between two sets of multidimensional variables, and thus offers the potential to combine these two approaches. To apply CCA, we must restrict the number of attributes relative to the number of samples. Hence we consider modules of genetic variation that can comprise a gene, a pathway or another biologically relevant grouping, and/or a set of phenotypes. In order to do this, we use an attribute selection strategy based on a binary genetic algorithm. Applied to a UK-based prospective cohort study of 4286 women (the British Women's Heart and Health Study, we find improved statistical power in the detection of previously reported genetic associations, and identify a number of novel pleiotropic associations between genetic variants and phenotypes. New discoveries include gene-based association of NSF with triglyceride levels and several genes (ACSM3, ERI2, IL18RAP, IL23RAP and NRG1 with left ventricular hypertrophy phenotypes. In multiple-phenotype analyses we find association of NRG1 with left ventricular hypertrophy phenotypes, fibrinogen and urea and pleiotropic relationships of F7 and F10 with Factor VII, Factor IX and cholesterol levels.
AN AGENT-BASED SIMULATION ON MARKET CONSIDERING KNOWLEDGE TRANSITION AND SOCIAL IMPACT
Institute of Scientific and Technical Information of China (English)
Tieju Ma; Mina Ryoke; Yoshiteru Nakamori
2002-01-01
In this paper, an agent-based simulation about knowledge transition associated with social impact in market is introduced. In the simulation, the genetic algorithm is used to generate the next generation products and a dynamic social impact model is used to simulate how customers are influenced by other customers. The simulation and its results not only show some features and patterns of knowledge transition, but also explore and display some phenomena of business cultures. On the basis of the innovation model of knowledge-based economy, the transition between technical knowledge and products knowledge is discussed, and a fuzzy linear quantification model which can be used to simulate the transition is introduced.
Structure-based prediction of protein-folding transition paths
Jacobs, William M
2016-01-01
We propose a general theory to describe the distribution of protein-folding transition paths. We show that transition paths follow a predictable sequence of high-free-energy transient states that are separated by free-energy barriers. Each transient state corresponds to the assembly of one or more discrete, cooperative units, which are determined directly from the native structure. We show that the transition state on a folding pathway is reached when a small number of critical contacts are formed between a specific set of substructures, after which folding proceeds downhill in free energy. This approach suggests a natural resolution for distinguishing parallel folding pathways and provides a simple means to predict the rate-limiting step in a folding reaction. Our theory identifies a common folding mechanism for proteins with diverse native structures and establishes general principles for the self-assembly of polymers with specific interactions.
Berndsen, M; VanderPligt, J; Spears, R
1996-01-01
The present study (n = 154) examines the effects of expectations and stimulus information on the perception of illusory correlation. There have been few studies attempting to integrate expectation-based and data- (distinctiveness-) based processes. These studies suggest that data-based illusory
Berndsen, M; VanderPligt, J; Spears, R
1996-01-01
The present study (n = 154) examines the effects of expectations and stimulus information on the perception of illusory correlation. There have been few studies attempting to integrate expectation-based and data- (distinctiveness-) based processes. These studies suggest that data-based illusory corr
Mass transit: devising a research-based marketing plan
Energy Technology Data Exchange (ETDEWEB)
Vanier, D.J.; Wotruba, T.R.
1977-08-01
This study presents a marketing planning procedural model that can be operationally used by marketing managers. The model enables the user to assess his company's performance on the various attributes of the marketing mix and to design a marketing program that caters to the needs of his marketplace. The model is applied here specifically to mass transit and is tested empirically. Within this context, it permits transit marketing to aim at increasing the probabilities of (i) greater usage on the part of existing riders and (ii) attracting prospects and converting them into actual customers.
Dynamical mean field theory-based electronic structure calculations for correlated materials.
Biermann, Silke
2014-01-01
We give an introduction to dynamical mean field approaches to correlated materials. Starting from the concept of electronic correlation, we explain why a theoretical description of correlations in spectroscopic properties needs to go beyond the single-particle picture of band theory.We discuss the main ideas of dynamical mean field theory and its use within realistic electronic structure calculations, illustrated by examples of transition metals, transition metal oxides, and rare-earth compounds. Finally, we summarise recent progress on the calculation of effective Hubbard interactions and the description of dynamical screening effects in solids.
Maintenance and Drainage Guidance for the Scott Base Transition, Antarctica
2014-10-01
12 12 Shake plates and clean off rock help shake dust and mud off vehicles and keep them clean prior to...water drilling to drain the retention ponds ......................................................................... 24 20 Drill sites for drainage...large cuts and chasms of ice melt and erosion will result. In addition, water and melting on the Land Transition results in mud , which invariably ends
Reference-based transitions in short-run price elasticity
K.H. Pauwels (Koen); Ph.H.B.F. Franses (Philip Hans); S. Srinivasan (Shruba)
2003-01-01
textabstractMarketing literature has long recognized that price response need not be monotonic and symmetric, but has yet to provide generalizable market-level insights on reference price type, asymmetric thresholds and sign and magnitude of elasticity transitions. In this paper, we introduce smooth
2007-01-01
We propose a new, cyclic-voltammetry based experimental technique that can not only differentiate between discontinuous and continuous phase transitions in an adsorbate layer, but also quite accurately recover equilibrium behavior from dynamic analysis of systems with a continuous phase transition. The Electrochemical first-order reversal curve (EC-FORC) diagram for a discontinuous phase transition (nucleation and growth), such as occurs in underpotential deposition, is characterized by a neg...
Windows Volatile Memory Forensics Based on Correlation Analysis
Directory of Open Access Journals (Sweden)
Xiaolu Zhang
2014-03-01
Full Text Available In this paper, we present an integrated memory forensic solution for multiple Windows memory images. By calculation, the method can find out the correlation degree among the processes of volatile memory images and the hidden clues behind the events of computers, which is usually difficult to be obtained and easily ignored by analyzing one single memory image and forensic investigators. In order to test the validity, we performed an experiment based on two hosts' memory image which contains criminal incidents. According to the experimental result, we find that the event chains reconstructed by our method are similar to the actual actions in the criminal scene. Investigators can review the digital crime scenario which is contained in the data set by analyzing the experimental results. This paper is aimed at finding the valid actions with illegal attempt and making the memory analysis not to be utterly dependent on the operating system and relevant experts.
Spanning Trees and bootstrap reliability estimation in correlation based networks
Tumminello, M; Lillo, F; Micciché, S; Mantegna, R N
2006-01-01
We introduce a new technique to associate a spanning tree to the average linkage cluster analysis. We term this tree as the Average Linkage Minimum Spanning Tree. We also introduce a technique to associate a value of reliability to links of correlation based graphs by using bootstrap replicas of data. Both techniques are applied to the portfolio of the 300 most capitalized stocks traded at New York Stock Exchange during the time period 2001-2003. We show that the Average Linkage Minimum Spanning Tree recognizes economic sectors and sub-sectors as communities in the network slightly better than the Minimum Spanning Tree does. We also show that the average reliability of links in the Minimum Spanning Tree is slightly greater than the average reliability of links in the Average Linkage Minimum Spanning Tree.
Traffic Prediction Based on Correlation of Road Sections
Directory of Open Access Journals (Sweden)
Xiaodan Huang
2013-10-01
Full Text Available Road section data packet is very necessary for the estimation and prediction in short-time traffic condition. However, previous researches on this problem are lack of quantitative analysis. A section correlation analyzing method with traffic flow microwave data is proposed for this problem. It is based on the metric multidimensional scaling theory. With a dissimilarity matrix, scalar product matrix can be calculated. Subsequently, a reconstructing matrix of section traffic flow could be got with principal components factor analysis, which could display section groups in low dimension. It is verified that the new method is reliable and effective. After that, Auto Regressive Moving Average (A RMA model is used for forecasting traffic flow and lane occupancy. Finally, a simulated example has shown that the technique is effective and exact. The theoretical analysis indicates that the forecasting model and algorithms have a broad prospect for practical application.
Preserving Differential Privacy in Degree-Correlation based Graph Generation
Directory of Open Access Journals (Sweden)
Yue Wang
2013-08-01
Full Text Available Enabling accurate analysis of social network data while preserving differential privacy has been challenging since graph features such as cluster coefficient often have high sensitivity, which is different from traditional aggregate functions (e.g., count and sum on tabular data. In this paper, we study the problem of enforcing edge differential privacy in graph generation. The idea is to enforce differential privacy on graph model parameters learned from the original network and then generate the graphs for releasing using the graph model with the private parameters. In particular, we develop a differential privacy preserving graph generator based on the dK-graph generation model. We first derive from the original graph various parameters (i.e., degree correlations used in the dK-graph model, then enforce edge differential privacy on the learned parameters, and finally use the dKgraph model with the perturbed parameters to generate graphs. For the 2K-graph model, we enforce the edge differential privacy by calibrating noise based on the smooth sensitivity, rather than the global sensitivity. By doing this, we achieve the strict differential privacy guarantee with smaller magnitude noise. We conduct experiments on four real networks and compare the performance of our private dK-graph models with the stochastic Kronecker graph generation model in terms of utility and privacy tradeoff. Empirical evaluations show the developed private dK-graph generation models significantly outperform the approach based on the stochastic Kronecker generation model.
Preserving Differential Privacy in Degree-Correlation based Graph Generation.
Wang, Yue; Wu, Xintao
2013-08-01
Enabling accurate analysis of social network data while preserving differential privacy has been challenging since graph features such as cluster coefficient often have high sensitivity, which is different from traditional aggregate functions (e.g., count and sum) on tabular data. In this paper, we study the problem of enforcing edge differential privacy in graph generation. The idea is to enforce differential privacy on graph model parameters learned from the original network and then generate the graphs for releasing using the graph model with the private parameters. In particular, we develop a differential privacy preserving graph generator based on the dK-graph generation model. We first derive from the original graph various parameters (i.e., degree correlations) used in the dK-graph model, then enforce edge differential privacy on the learned parameters, and finally use the dK-graph model with the perturbed parameters to generate graphs. For the 2K-graph model, we enforce the edge differential privacy by calibrating noise based on the smooth sensitivity, rather than the global sensitivity. By doing this, we achieve the strict differential privacy guarantee with smaller magnitude noise. We conduct experiments on four real networks and compare the performance of our private dK-graph models with the stochastic Kronecker graph generation model in terms of utility and privacy tradeoff. Empirical evaluations show the developed private dK-graph generation models significantly outperform the approach based on the stochastic Kronecker generation model.
Energy Technology Data Exchange (ETDEWEB)
Steffen, Jason H.; /Fermilab; Fabrycky, Daniel C.; /Lick Observ.; Ford, Eric B.; /Florida U.; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Welsh, William F.; /Caltech; Borucki, William J.; /NASA, Ames /UC, Santa Barbara
2012-01-01
We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anticorrelations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems, Kepler-25, Kepler-26, Kepler-27 and Kepler-28, containing eight planets and one additional planet candidate.
Park, Hyungkwon; Kim, Jinyoung; Lee, Sung Bo; Lee, Changhee
2016-12-01
Vacuum kinetic spraying (VKS) is a promising room-temperature process to fabricate dense ceramic films. However, unfortunately, the deposition mechanism is still not clearly understood. In this respect, the critical conditions for successful deposition were investigated. Based on simulation and microstructural analysis, it was found that as the particle velocity increased, fracture mode transition from tensile fracture to shear fracture occurred and particle did not bounce off anymore above a certain velocity. Simultaneously, particle underwent shock-induced plasticity and dynamic fragmentation. The plasticity assisted to prevent the fragments from rebounding by spending the excessive kinetic energy and fragmentation is essential for fragment bonding and film growth considering that the deposition rate increased as the fraction of fragmentation increased. Accordingly, plasticity and fragmentation take a crucial role for particle deposition. In this respect, the velocity that fracture mode transition occurs is newly defined as critical velocity. Consequently, for successful deposition, the particle should at least exceed the critical velocity and thus it is very crucial for film fabrication in VKS process at room temperature.
Dynamically reconfigurable multiple beam illumination based on optical correlation
DEFF Research Database (Denmark)
Glückstad, Jesper; Palima, Darwin; Dam, Jeppe Seidelin
2009-01-01
We adapt concepts from optical correlation and optical pattern recognition to propose a method for generating reconfigurable multiple spots with high efficiency. The generated spots correspond to the correlation spikes in optical pattern recognition. In pattern recognition, optimizing the correla...
Baró, Jordi; Martín-Olalla, José-María; Romero, Francisco Javier; Gallardo, María Carmen; Salje, Ekhard K H; Vives, Eduard; Planes, Antoni
2014-03-26
The existence of temporal correlations during the intermittent dynamics of a thermally driven structural phase transition is studied in a Cu-Zn-Al alloy. The sequence of avalanches is observed by means of two techniques: acoustic emission and high sensitivity calorimetry. Both methods reveal the existence of event clustering in a way that is equivalent to the Omori correlations between aftershocks in earthquakes as are commonly used in seismology.
Directory of Open Access Journals (Sweden)
Attila Szolnoki
2013-11-01
Full Text Available Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments.
Zhao, Jieying; Chen, Guangchun; Cao, Dongmei; Li, Yidong; Diao, Fei; Cai, Haoyu; Jin, Yiduo; Lu, Jian
2010-01-01
The failure of breast cancer treatment is largely due to the development of estrogen independence. Current data illustrate that Hedgehog (Hh) signaling may play an important role in breast cancer development. Here, we show that the expression of the Hh effector protein, Gli1 was significantly higher in estrogen-independent breast cancer cells than in estrogen-dependent cells. Our data showed for the first time that stable expression of Gli1 in ER positive breast cancer cell lines MCF-7 and T47D can induce estrogen-independent proliferation and promote G1/S phase transition, which associated with cyclin-Rb axi. Gli1 can also attenuate the response of proliferation to estrogenic stimulation, which was correlated with down-regulation of expression of ERalpha and PR, as well as down-regulation of transactivation of ERalpha. Our results suggest that up-regulation of Gli1 in breast cancer cells may be one of the mechanisms responsible for developing estrogen independence and this process may be regulated through down-regulation of expression and transactivation of ERalpha.
Szolnoki, Attila; Perc, Matjaž
2013-10-01
Economic experiments reveal that humans value cooperation and fairness. Punishing unfair behavior is therefore common, and according to the theory of strong reciprocity, it is also directly related to rewarding cooperative behavior. However, empirical data fail to confirm that positive and negative reciprocity are correlated. Inspired by this disagreement, we determine whether the combined application of reward and punishment is evolutionarily advantageous. We study a spatial public goods game, where in addition to the three elementary strategies of defection, rewarding, and punishment, a fourth strategy that combines the latter two competes for space. We find rich dynamical behavior that gives rise to intricate phase diagrams where continuous and discontinuous phase transitions occur in succession. Indirect territorial competition, spontaneous emergence of cyclic dominance, as well as divergent fluctuations of oscillations that terminate in an absorbing phase are observed. Yet, despite the high complexity of solutions, the combined strategy can survive only in very narrow and unrealistic parameter regions. Elementary strategies, either in pure or mixed phases, are much more common and likely to prevail. Our results highlight the importance of patterns and structure in human cooperation, which should be considered in future experiments.
Goodpaster, Jason D; Manby, Frederick R; Miller, Thomas F
2012-01-01
Density functional theory (DFT) embedding provides a formally exact framework for interfacing correlated wave-function theory (WFT) methods with lower-level descriptions of electronic structure. Here, we report techniques to improve the accuracy and stability of WFT-in-DFT embedding calculations. In particular, we develop spin-dependent embedding potentials in both restricted and unrestricted orbital formulations to enable WFT-in-DFT embedding for open-shell systems, and we develop an orbital-occupation-freezing technique to improve the convergence of optimized effective potential (OEP) calculations that arise in the evaluation of the embedding potential. The new techniques are demonstrated in applications to the van-der-Waals-bound ethylene-propylene dimer and to the hexaaquairon(II) transition-metal cation. Calculation of the dissociation curve for the ethylene-propylene dimer reveals that WFT-in-DFT embedding reproduces full CCSD(T) energies to within 0.1 kcal/mol at all distances, eliminating errors in th...
SIW based multilayer transition and power divider in LTCC technology
Abuzaid, Hattan
2013-06-01
A multilayer transition and balanced power divider are presented for millimeter-wave system-on-package (SoP). These two components operate at Ka-band and exploit the substrate integrate waveguide (SIW) technology with its shielding characteristics and the Low-temperature co-fired ceramics (LTCC) technology for its high density integration. A coupling slot has been used to perform vertical integration, which can be easily optimized through its length. The measured input return loss within the bandwidth of interest (32 GHz-38 GHz) is less than -15 dB and -18 dB for the multilayer transition and the power divider, respectively. The lateral dimensions of a multilayer system, such as a feed network of an array, can be greatly reduced by employing these 3D slot-coupled components. © 2013 IEEE.
Exploratory Phase Transition-Based Switches Using Functional Oxides
2011-02-02
structure was tested and the accuracy of Φ was estimated as ~ 0.02 eV.13 30 nm-thick Au/Cr layer including windows of 2 × 0.2 mm2 was coated on VO2 films...1039. (2) Mott, N. F. Metal-Insulator Transition. Reviews of Modern Physics 1968, 40, 677. (3) Goodenough , J. B. The two components of the
Evaluation of Achieving a College Education Plus: A Credit-Based Transition Program
Luna, Gaye; Fowler, Michael
2011-01-01
This ex post facto study evaluated Achieving a College Education (ACE) Plus program, a credit-based transition program between a high school district and a community college. Achieving a College Education Plus is an early outreach program. It is designed to aid at-risk students in graduating from high school and making a smooth transition to…
Digital image correlation based on a fast convolution strategy
Yuan, Yuan; Zhan, Qin; Xiong, Chunyang; Huang, Jianyong
2017-10-01
In recent years, the efficiency of digital image correlation (DIC) methods has attracted increasing attention because of its increasing importance for many engineering applications. Based on the classical affine optical flow (AOF) algorithm and the well-established inverse compositional Gauss-Newton algorithm, which is essentially a natural extension of the AOF algorithm under a nonlinear iterative framework, this paper develops a set of fast convolution-based DIC algorithms for high-efficiency subpixel image registration. Using a well-developed fast convolution technique, the set of algorithms establishes a series of global data tables (GDTs) over the digital images, which allows the reduction of the computational complexity of DIC significantly. Using the pre-calculated GDTs, the subpixel registration calculations can be implemented efficiently in a look-up-table fashion. Both numerical simulation and experimental verification indicate that the set of algorithms significantly enhances the computational efficiency of DIC, especially in the case of a dense data sampling for the digital images. Because the GDTs need to be computed only once, the algorithms are also suitable for efficiently coping with image sequences that record the time-varying dynamics of specimen deformations.
Traffic Sign Recognition System based on Cambridge Correlator Image Comparator
Directory of Open Access Journals (Sweden)
J. Turan
2012-06-01
Full Text Available Paper presents basic information about application of Optical Correlator (OC, specifically Cambridge Correlator, in system to recognize of traffic sign. Traffic Sign Recognition System consists of three main blocks, Preprocessing, Optical Correlator and Traffic Sign Identification. The Region of Interest (ROI is defined and chosen in preprocessing block and then goes to Optical Correlator, where is compared with database of Traffic Sign. Output of Optical Correlation is correlation plane, which consist of highly localized intensities, know as correlation peaks. The intensity of spots provides a measure of similarity and position of spots, how images (traffic signs are relatively aligned in the input scene. Several experiments have been done with proposed system and results and conclusion are discussed.
Estimating genetic correlations based on phenotypic data: a simulation-based method
Indian Academy of Sciences (India)
Elias Zintzaras
2011-04-01
Knowledge of genetic correlations is essential to understand the joint evolution of traits through correlated responses to selection, a difficult and seldom, very precise task even with easy-to-breed species. Here, a simulation-based method to estimate genetic correlations and genetic covariances that relies only on phenotypic measurements is proposed. The method does not require any degree of relatedness in the sampled individuals. Extensive numerical results suggest that the propose method may provide relatively efficient estimates regardless of sample sizes and contributions from common environmental effects.
Shukla, Manoj K.; Leszczynski, Jerzy
2010-11-01
A comprehensive analysis of the performance of the TD-DFT method using different density functionals including recently developed medium and long-range correlation corrected density functionals have been carried out for lower-lying electronic singlet valence transitions of nucleic acid bases and the Watson-Crick base pairs in the gas phase and in the water solution. The standard 6-311++G(d,p) basis set was used. Ground state geometries of bases and base pairs were optimized at the M05-2X/6-311++G(d,p) level. The nature of potential energy surfaces (PES) was ascertained through the harmonic vibrational frequency analysis; all geometries were found to be minima at the respective PES. Electronic singlet vertical transition energies were also computed at the CC2/def2-TZVP level in the gas phase. The effect of state-specific water solvation on TD-DFT computed transition energies was considered using the PCM model. For the isolated bases the performance of the B3LYP functional was generally found to be superior among all functionals, but it measurably fails for charge-transfer states in the base pairs. The CC2/def2-TZVP computed transition energies were also revealed to be inferior compared with B3LYP results for the isolated bases. The performance of the ωB97XD, CAM-B3LYP and BMK functionals were found to be similar and comparable with the CC2 results for the isolated bases. However, for the Watson-Crick adenine-thymine and guanine-cytosine base pairs the performance of the ωB97XD functional was found to be the best among all the studied functionals in the present work in predicting the locally excited transitions as well as charge transfer states.
Quantum hidden Markov models based on transition operation matrices
Cholewa, Michał; Gawron, Piotr; Głomb, Przemysław; Kurzyk, Dariusz
2017-04-01
In this work, we extend the idea of quantum Markov chains (Gudder in J Math Phys 49(7):072105 [3]) in order to propose quantum hidden Markov models (QHMMs). For that, we use the notions of transition operation matrices and vector states, which are an extension of classical stochastic matrices and probability distributions. Our main result is the Mealy QHMM formulation and proofs of algorithms needed for application of this model: Forward for general case and Vitterbi for a restricted class of QHMMs. We show the relations of the proposed model to other quantum HMM propositions and present an example of application.
Bolund, E; Lummaa, V
2017-02-01
Studies of evolutionary change require an estimate of fitness, and lifetime reproductive success is widely used for this purpose. However, many species face a trade-off between the number and quality of offspring and in such cases number of grandoffspring may better represent the genetic contribution to future generations. Here, we apply quantitative genetic methods to a genealogical data set on humans from Finland to address how the genetic correlation between number of children and grandchildren is influenced by the severity of the trade-off between offspring quality and quantity, as estimated by different levels of resource access among individuals in the population. Further, we compare the genetic correlation before and after the demographic transition to low mortality and fertility rates. The genetic correlation was consistently high (0.79-0.92) with the strongest correlations occurring in individuals with higher access to resources and before the demographic transition, and a tendency for lower correlations in resource poor individuals and after the transition. These results indicate that number of grandoffspring is a slightly better predictor of long-term genetic fitness than number of offspring in a human population across a range of environmental conditions, and more generally, that patterns of resource availability need to be taken into account when estimating genetic covariances with fitness.
STOCK Market Differences in Correlation-Based Weighted Network
Youn, Janghyuk; Lee, Junghoon; Chang, Woojin
We examined the sector dynamics of Korean stock market in relation to the market volatility. The daily price data of 360 stocks for 5019 trading days (from January, 1990 to August, 2008) in Korean stock market are used. We performed the weighted network analysis and employed four measures: the average, the variance, the intensity, and the coherence of network weights (absolute values of stock return correlations) to investigate the network structure of Korean stock market. We performed regression analysis using the four measures in the seven major industry sectors and the market (seven sectors combined). We found that the average, the intensity, and the coherence of sector (subnetwork) weights increase as market becomes volatile. Except for the "Financials" sector, the variance of sector weights also grows as market volatility increases. Based on the four measures, we can categorize "Financials," "Information Technology" and "Industrials" sectors into one group, and "Materials" and "Consumer Discretionary" sectors into another group. We investigated the distributions of intrasector and intersector weights for each sector and found the differences in "Financials" sector are most distinct.
Atlas-based diffusion tensor imaging correlates of executive function
Nowrangi, Milap A.; Okonkwo, Ozioma; Lyketsos, Constantine; Oishi, Kenichi; Mori, Susumu; Albert, Marilyn; Mielke, Michelle M.
2015-01-01
Impairment in executive function (EF) is commonly found in Alzheimer’s Dementia (AD) and Mild Cognitive Impairment (MCI). Atlas-based Diffusion Tensor Imaging (DTI) methods may be useful in relating regional integrity to EF measures in MCI and AD. 66 participants (25 NC, 22 MCI, and 19 AD) received DTI scans and clinical evaluation. DTI scans were applied to a pre-segmented atlas and fractional anisotropy (FA) and mean diffusivity (MD) were calculated. ANOVA was used to assess group differences in frontal, parietal, and cerebellar regions. For regions differing between groups (p<0.01), linear regression examined the relationship between EF scores and regional FA and MD. Anisotropy and diffusivity in frontal and parietal lobe white matter (WM) structures were associated with EF scores in MCI and only frontal lobe structures in AD. EF was more strongly associated with FA than MD. The relationship between EF and anisotropy and diffusivity was strongest in MCI. These results suggest that regional WM integrity is compromised in MCI and AD and that FA may be a better correlate of EF than MD. PMID:25318544
A study of combined evaluation of suppliers based on correlation
Directory of Open Access Journals (Sweden)
Heting Qiu
2013-03-01
Full Text Available Purpose: The Selection of logistics service providers is an important issue in supply chain management. But different evaluation methods may lead to different results, which could cause inconsistent conclusions. This paper makes use of a new perspective to combine with a variety of methods to eliminate the deviation of different single evaluation methods. Design/methodology/approach: This paper expounds the application of the combined evaluation method based on correlation. Entropy method, factor analysis, grey colligation evaluation and AHP have been used for research. Findings: According to the evaluate result, the ranking of suppliers obtained by each method have obvious differences. The result shows that combined evaluation method can eliminate the deviation of different single evaluation methods. Originality/value: The combined evaluation method makes up for the defects of single evaluation methods and obtains a result that is more stable and creditable with smaller deviation. This study can provide the enterprise leaders with more scientific method to select their cooperative companies.
Video quality assessment based on correlation between spatiotemporal motion energies
Yan, Peng; Mou, Xuanqin
2016-09-01
Video quality assessment (VQA) has been a hot research topic because of rapid increase of huge demand of video communications. From the earliest PSNR metric to advanced models that are perceptual aware, researchers have made great progress in this field by introducing properties of human vision system (HVS) into VQA model design. Among various algorithms that model the property of HVS perceiving motion, the spatiotemporal energy model has been validated to be high consistent with psychophysical experiments. In this paper, we take the spatiotemporal energy model into VQA model design by the following steps. 1) According to the pristine spatiotemporal energy model proposed by Adelson et al, we apply the linear filters, which are oriented in space-time and tuned in spatial frequency, to filter the reference and test videos respectively. The outputs of quadrature pairs of above filters are then squared and summed to give two measures of motion energy, which are named rightward and leftward energy responses, respectively. 2) Based on the pristine model, we calculate summation of the rightward and leftward energy responses as spatiotemporal features to represent perceptual quality information for videos, named total spatiotemporal motion energy maps. 3) The proposed FR-VQA model, named STME, is calculated with statistics based on the pixel-wise correlation between the total spatiotemporal motion energy maps of the reference and distorted videos. The STME model was validated on the LIVE VQA Database by comparing with existing FR-VQA models. Experimental results show that STME performs with excellent prediction accuracy and stays in state-of-the-art VQA models.
On the base size of a transitive group with solvable point stabilizer
Evgeny, Vdovin
2010-01-01
We prove that the base size of a transitive group $G$ with solvable point stabilizer is not greater than $k$ provided the same statement holds for every group of $G$-induced automorphisms of each nonabelian composition factor of $G$.
Study of Key Factors Determinant Choice of Rail-Based Mass Transit
Directory of Open Access Journals (Sweden)
Ircham
2016-07-01
Full Text Available Pursuant to regulations of the Ministry of Transportation in 2002 about the type of transport based on the city size, the metropolis with a population of more than 1 million inhabitants are required to have the urban mass transit. Nevertheless, until now not all city-scale population of more than 1 million have mass public transport, either bus or rail-based. Especially for rail-based mass transit, indicated the existing regulations have not been able to challenge the development of rail-based urban mass transit. Learning from the literature study and the experience of countries that already have rail-based urban mass transit it has acquired nine main factors to be taken into account in developing a rail-based urban public transportation. This study was conducted by using Analytical Hierarchy Process method which was further validated through the implementation of the On Focus Group Discussion in the Jakarta City Transportation Council (DTKJ as well as in the City Development Planning Board (Bappeko Surabaya. Finally, the initial result shown five sequences determining factor for the determinant choice of rail-based mass transit, namely: fiscal or economic capacity of the region and society, transport policy, integrated public transport, land use, fare and travel time. Furthermore, the acquisition results of this study can be applied to the selected cities to address the challenges to urban mass transit development.
Correlation methods of base-level cycle based on wavelet neural network
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The authors discussed the method of wavelet neural network (WNN) for correlation of base-level cycle. A new vectored method of well log data was proposed. Through the training with the known data set, the WNN can remenber the cycle pattern characteristic of the well log curves. By the trained WNN to identify the cycle pattern in the vectored log data, the ocrrelation process among the well cycles was completed. The application indicates that it is highly efficient and reliable in base-level cycle correlation.
A transit timing analysis with combined ground- and space-based photometry
Directory of Open Access Journals (Sweden)
Raetz St.
2015-01-01
The CoRoT satellite looks back on six years of high precision photometry of a very high number of stars. Thousands of transiting events are detected from which 27 were confirmed to be transiting planets so far. In my research I search and analyze TTVs in the CoRoT sample and combine the unprecedented precision of the light curves with ground-based follow-up photometry. Because CoRoT can observe transiting planets only for a maximum duration of 150 days the ground-based follow-up can help to refine the ephemeris. Here we present first examples.
A Net Energy-based Analysis for a Climate-constrained Sustainable Energy Transition
Sgouridis, Sgouris; Bardi, Ugo; Csala, Denes
2015-01-01
The transition from a fossil-based energy economy to one based on renewable energy is driven by the double challenge of climate change and resource depletion. Building a renewable energy infrastructure requires an upfront energy investment that subtracts from the net energy available to society. This investment is determined by the need to transition to renewable energy fast enough to stave off the worst consequences of climate change and, at the same time, maintain a sufficient net energy fl...
MRMaid, the web-based tool for designing multiple reaction monitoring (MRM) transitions.
Mead, Jennifer A; Bianco, Luca; Ottone, Vanessa; Barton, Chris; Kay, Richard G; Lilley, Kathryn S; Bond, Nicholas J; Bessant, Conrad
2009-04-01
Multiple reaction monitoring (MRM) of peptides uses tandem mass spectrometry to quantify selected proteins of interest, such as those previously identified in differential studies. Using this technique, the specificity of precursor to product transitions is harnessed for quantitative analysis of multiple proteins in a single sample. The design of transitions is critical for the success of MRM experiments, but predicting signal intensity of peptides and fragmentation patterns ab initio is challenging given existing methods. The tool presented here, MRMaid (pronounced "mermaid") offers a novel alternative for rapid design of MRM transitions for the proteomics researcher. The program uses a combination of knowledge of the properties of optimal MRM transitions taken from expert practitioners and literature with MS/MS evidence derived from interrogation of a database of peptide identifications and their associated mass spectra. The tool also predicts retention time using a published model, allowing ordering of transition candidates. By exploiting available knowledge and resources to generate the most reliable transitions, this approach negates the need for theoretical prediction of fragmentation and the need to undertake prior "discovery" MS studies. MRMaid is a modular tool built around the Genome Annotating Proteomic Pipeline framework, providing a web-based solution with both descriptive and graphical visualizations of transitions. Predicted transition candidates are ranked based on a novel transition scoring system, and users may filter the results by selecting optional stringency criteria, such as omitting frequently modified residues, constraining the length of peptides, or omitting missed cleavages. Comparison with published transitions showed that MRMaid successfully predicted the peptide and product ion pairs in the majority of cases with appropriate retention time estimates. As the data content of the Genome Annotating Proteomic Pipeline repository increases
Performance of VBLAST Systems Based on Spatial Correlated MIMO Channels
Institute of Scientific and Technical Information of China (English)
WANG Zhong-peng; QIU Zhong-yuan; WU Wei-ling
2004-01-01
Vertically-layered Bell Laboratories Layered Space-Time (VBLAST) is one of the most promising techniques for realizing high spectral efficiencies over wireless link. In previously published work, the performance of VBLAST has been primarily investigated in uncorrelated Rayleigh fading channels. However in real environments some correlation between antenna elements can be presented. In this paper, we study the impact of transmit correlation on the performance of VBLAST systems. Finally we provide simulation results demonstrating the impact of spatial fading correlation on the symbol error rate of VBLAST.
Honda, Z.; Sato, S.; Hagiwara, M.; Kida, T.; Sakai, M.; Fukuda, T.; Kamata, N.
2016-07-01
A simple method for the preparation of bulk quantities of magnetic carbon materials, which contain uniformly dispersed transition metals (M = Fe, Co, Ni, and Cu) as the magnetic components, is presented. By using highly chlorinated metal phthalocyanine as the building block and potassium as the coupling reagent, phthalocyanine-based carbon materials (PBCMs) containing transition metals were obtained. Our experiments demonstrate the structure of these PBCMs consists of transition metals embedded in graphitic carbon that includes a square planar MN4 magnetic core and the Fe and Co-PBCM possess spontaneous magnetization at room temperature. In addition, carbon-coated transition metal particles were obtained by the Wurtz-type reaction with excess amount of potassium coupling agent. The large transition metal surface area and magnetization of these M-PBCMs are useful for spintronic and catalytic applications.
Hamad, Ibrahim Abou; Novotny, Mark A; Rikvold, Per Arne
2007-01-01
We propose a new, cyclic-voltammetry based experimental technique that can not only differentiate between discontinuous and continuous phase transitions in an adsorbate layer, but also quite accurately recover equilibrium behavior from dynamic analysis of systems with a continuous phase transition. The Electrochemical first-order reversal curve (EC-FORC) diagram for a discontinuous phase transition (nucleation and growth), such as occurs in underpotential deposition, is characterized by a negative region, while such a region does not exist for a continuous phase transition, such as occurs in the electrosorption of Br on Ag(100). Moreover, for systems with a continuous phase transition, the minima of the individual EC-FORCs trace the equilibrium curve, even at very high scan rates. Since obtaining experimental data for the EC-FORC method would require only a simple reprogramming of the potentiostat used in conventional cyclic-voltammetry experiments, we believe that this method has significant potential for ea...
Composition and size dependent brittle-to-malleable transitions of Mg-based bulk metallic glasses
Energy Technology Data Exchange (ETDEWEB)
Yin, Jian, E-mail: yinjiandonic@yahoo.com; Ma, Xiujun; Zhou, Zhijian
2014-05-01
Mg-based bulk metallic glasses (BMGs) were often treated as brittle materials. However, some Mg-based BMGs were recently reported to show malleability. In order to identify the reasons for the achievement of the brittle-to-malleable transitions in the Mg-based BMGs, we systematically investigated the mechanical properties of four Mg-based BMGs (Mg{sub 65}Cu{sub 25}Gd{sub 10}, Mg{sub 65}Cu{sub 20}Ni{sub 5}Gd{sub 10}, Mg{sub 75}Ni{sub 15}Gd{sub 10}, and Mg{sub 75}Ni{sub 15}Gd{sub 5}Nd{sub 5} BMGs) using the uniaxial compression tests on the samples with sizes of ∅1×2 mm{sup 2} and ∅2×4 mm{sup 2}. The corresponding fracture morphology was observed by scanning electron microscopy (SEM). These Mg-based BMGs displayed the composition or size dependent brittle-to-malleable transitions, accompanied by the fracture mode transition from the cleavage fracture to the shear fracture. It appeared that the Mg-based BMGs were sensitive to cleavage cracks upon loading. The brittle-to-malleable transitions of the Mg-based BMGs were related to not only the stability of shear banding but also the nucleation and propagation of cleavage cracks. It was demonstrated that the suppression of the nucleation and propagation of cleavage cracks could favor the transition from the cleavage fracture to the shear fracture and encourage the brittle-to-malleable transition for the Mg-based BMGs. The underlying mechanism for the brittle-to-malleable transitions of the Mg-based BMGs was discussed with respect to both the composition and size effects.
Fuzzy rule-based seizure prediction based on correlation dimension changes in intracranial EEG.
Rabbi, Ahmed F; Aarabi, Ardalan; Fazel-Rezai, Reza
2010-01-01
In this paper, we present a method for epileptic seizure prediction from intracranial EEG recordings. We applied correlation dimension, a nonlinear dynamics based univariate characteristic measure for extracting features from EEG segments. Finally, we designed a fuzzy rule-based system for seizure prediction. The system is primarily designed based on expert's knowledge and reasoning. A spatial-temporal filtering method was used in accordance with the fuzzy rule-based inference system for issuing forecasting alarms. The system was evaluated on EEG data from 10 patients having 15 seizures.
Sampling of general correlators in worm-algorithm based simulations
Rindlisbacher, Tobias; Åkerlund, Oscar; de Forcrand, Philippe
2016-08-01
Using the complex ϕ4-model as a prototype for a system which is simulated by a worm algorithm, we show that not only the charged correlator , but also more general correlators such as or , as well as condensates like , can be measured at every step of the Monte Carlo evolution of the worm instead of on closed-worm configurations only. The method generalizes straightforwardly to other systems simulated by worms, such as spin or sigma models.
Sampling of General Correlators in Worm Algorithm-based Simulations
Rindlisbacher, Tobias; de Forcrand, Philippe
2016-01-01
Using the complex $\\phi^4$-model as a prototype for a system which is simulated by a (bosonic) worm algorithm, we show that not only the charged correlator $$, but also more general correlators such as $$ or $$ as well as condensates like $$ can be measured at every step of the Monte Carlo evolution of the worm instead of on closed-worm configurations only. The method generalizes straightforwardly to other systems simulated by (bosonic) worms, such as spin or sigma models.
Chord Recognition Based on Temporal Correlation Support Vector Machine
Zhongyang Rao; Xin Guan; Jianfu Teng
2016-01-01
In this paper, we propose a method called temporal correlation support vector machine (TCSVM) for automatic major-minor chord recognition in audio music. We first use robust principal component analysis to separate the singing voice from the music to reduce the influence of the singing voice and consider the temporal correlations of the chord features. Using robust principal component analysis, we expect the low-rank component of the spectrogram matrix to contain the musical accompaniment and...
Silveira, Camila Magalhães; Viana, Maria Carmen; Siu, Erica Rosanna; Guerra de Andrade, Arthur; Anthony, James C.; Andrade, Laura Helena
2011-01-01
Aims: To evaluate sociodemographic correlates associated with transitions from alcohol use to disorders and remission in a Brazilian population. Methods: Data are from a probabilistic, multi-stage clustered sample of adult household residents in the São Paulo Metropolitan Area. Alcohol use, regular use (at least 12 drinks/year), DSM-IV abuse and dependence and remission from alcohol use disorders (AUDs) were assessed with the World Mental Health version of the Composite International Diagnostic Interview. Age of onset (AOO) distributions of the cumulative lifetime probability of each alcohol use stage were prepared with data obtained from 5037 subjects. Correlates of transitions were obtained from a subsample of 2942 respondents, whose time-dependent sociodemographic data were available. Results: Lifetime prevalences were 85.8% for alcohol use, 56.2% for regular use, 10.6% for abuse and 3.6% for dependence; 73.4 and 58.8% of respondents with lifetime abuse and dependence, respectively, had remitted. The number of sociodemographic correlates decreased from alcohol use to disorders. All transitions across alcohol use stages up to abuse were consistently associated with male gender, younger cohorts and lower education. Importantly, low education was a correlate for developing AUD and not remitting from dependence. Early AOO of first alcohol use was associated with the transition of regular use to abuse. Conclusion: The present study demonstrates that specific correlates differently contribute throughout alcohol use trajectory in a Brazilian population. It also reinforces the need of preventive programs focused on early initiation of alcohol use and high-risk individuals, in order to minimize the progression to dependence and improve remission from AUD. PMID:21414952
Energy Technology Data Exchange (ETDEWEB)
Bian, Liang, E-mail: bianliang@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Dong, Fa-qin; Song, Mian-xin [Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Dong, Hai-liang [Department of Geology and Environmental Earth Science, Miami University, Oxford, OH 45056 (United States); Li, Wei-Min [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Duan, Tao; Xu, Jin-bao [Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Zhang, Xiao-yan [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China)
2015-08-30
Highlights: • Effect of Pu f-shell electron on the electronic property of zircon is calculated via DFT and 2D-CA techniques. • Reasons of Pu f-shell electron influencing on electronic properties are systematically discussed. • Phase transitions are found at two point 2.8 mol% and 7.5 mol%. - Abstract: Understanding how plutonium (Pu) doping affects the crystalline zircon structure is very important for risk management. However, so far, there have been only a very limited number of reports of the quantitative simulation of the effects of the Pu charge and concentration on the phase transition. In this study, we used density functional theory (DFT), virtual crystal approximation (VCA), and two-dimensional correlation analysis (2D-CA) techniques to calculate the origins of the structural and electronic transitions of Zr{sub 1−c}Pu{sub c}SiO{sub 4} over a wide range of Pu doping concentrations (c = 0–10 mol%). The calculations indicated that the low-angular-momentum Pu-f{sub xy}-shell electron excites an inner-shell O-2s{sup 2} orbital to create an oxygen defect (V{sub O-s}) below c = 2.8 mol%. This oxygen defect then captures a low-angular-momentum Zr-5p{sup 6}5s{sup 2} electron to form an sp hybrid orbital, which exhibits a stable phase structure. When c > 2.8 mol%, each accumulated V{sub O-p} defect captures a high-angular-momentum Zr-4d{sub z} electron and two Si-p{sub z} electrons to create delocalized Si{sup 4+} → Si{sup 2+} charge disproportionation. Therefore, we suggest that the optimal amount of Pu cannot exceed 7.5 mol% because of the formation of a mixture of ZrO{sub 8} polyhedral and SiO{sub 4} tetrahedral phases with the orientation (10-1). This study offers new perspective on the development of highly stable zircon-based solid solution materials.
Kepler and Ground-Based Transits of the exo-Neptune HAT-P-11b
Deming, Drake; Sada, Pedro V.; Jackson, Brian; Peterson, Steven W.; Agol, Eric; Knutson, Heather A.; Jennings, Donald E.; Haase, Plynn; Bays, Kevin
2011-01-01
We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields Rp = 4.31 R xor 0.06 R xor and Rs = 0.683 R solar mass 0.009 R solar mass, both about 3 sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ 436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler transit data. We develop and apply a methodology to correct the planetary radius for the presence of both crossed and uncrossed star spots. Star spot crossings are concentrated at phases 0.002 and +0.006. This is consistent with inferences from Rossiter-McLaughlin measurements that the planet transits nearly perpendicular to the stellar equator. We identify the dominant phases of star spot crossings with active latitudes on the star, and infer that the stellar rotational pole is inclined at about 12 deg 5 deg to the plane of the sky. We point out that precise transit measurements over long durations could in principle allow us to construct a stellar Butterfly diagram to probe the cyclic evolution of magnetic activity on this active K-dwarf star.
Feasibility analysis of phase transition signals based on e-bike rider behavior
Directory of Open Access Journals (Sweden)
Sheng Dong
2015-11-01
Full Text Available This article evaluates the feasibility of two scenarios of phase transition signals, that is, the flashing green together with red–yellow light and the green countdown together with red countdown, at signalized intersections in terms of e-bike rider behavior. An evaluation framework is first proposed. During the phase transition, the stop-go and start-up behavioral parameters are collected at four intersections in Shanghai, China. Sensitivity analysis is then performed to identify the most significant factors that influence the occurrence of traffic conflicts during the phase transition. Based on the above analysis results, case studies were finally done to look into safety performance of the two scenarios of phase transition signals, indicated by the distributions of post encroachment time at the conflict point and the occurring probability of extremely small post encroachment times. Research result shows the transition signal combination of green countdown + red countdown tends to cause traffic accidents more easily and thus less safe compared to the transition signal combination of flashing green + red-yellow. Unlike the conventional method generally based on the deterministic traffic flow theory, the proposed methodology has a wide application. With the aid of it, traffic engineers are capable of designing transition signals in a more scientific manner.
Speller-Brown, Barbara; Patterson Kelly, Katherine; VanGraafeiland, Brigit; Feetham, Suzanne; Sill, Anne; Darbari, Deepika; Meier, Emily R
2015-01-01
Adolescents and young adults (AYAs) often transfer from pediatric to adult care without adequate preparation, resulting in increased morbidity and mortality. The purpose of this descriptive research study of parent/AYA dyads was to measure perceptions of transition readiness. Factors that were found to be associated with perceptions of increased readiness to transition included AYA age, the amount of responsibility AYAs assume for their healthcare and the degree of parent involvement. More attention should be focused on these aspects of care to improve transition from pediatric to adult care for AYAs with sickle cell disease. Copyright © 2015 Elsevier Inc. All rights reserved.
Coupled-cluster based basis sets for valence correlation calculations
Claudino, Daniel; Gargano, Ricardo; Bartlett, Rodney J.
2016-03-01
Novel basis sets are generated that target the description of valence correlation in atoms H through Ar. The new contraction coefficients are obtained according to the Atomic Natural Orbital (ANO) procedure from CCSD(T) (coupled-cluster singles and doubles with perturbative triples correction) density matrices starting from the primitive functions of Dunning et al. [J. Chem. Phys. 90, 1007 (1989); ibid. 98, 1358 (1993); ibid. 100, 2975 (1993)] (correlation consistent polarized valence X-tuple zeta, cc-pVXZ). The exponents of the primitive Gaussian functions are subject to uniform scaling in order to ensure satisfaction of the virial theorem for the corresponding atoms. These new sets, named ANO-VT-XZ (Atomic Natural Orbital Virial Theorem X-tuple Zeta), have the same number of contracted functions as their cc-pVXZ counterparts in each subshell. The performance of these basis sets is assessed by the evaluation of the contraction errors in four distinct computations: correlation energies in atoms, probing the density in different regions of space via (-3 ≤ n ≤ 3) in atoms, correlation energies in diatomic molecules, and the quality of fitting potential energy curves as measured by spectroscopic constants. All energy calculations with ANO-VT-QZ have contraction errors within "chemical accuracy" of 1 kcal/mol, which is not true for cc-pVQZ, suggesting some improvement compared to the correlation consistent series of Dunning and co-workers.
Image automatic mosaics based on contour phase correlation
Institute of Scientific and Technical Information of China (English)
ZHANG Jing; HU Zhiping; LIU Zhitai; OU Zongying
2007-01-01
The image planar mosaics is studied,and an image automatic mosaics algorithm on the basis of contour phase correlation is proposed in this paper.To begin with,by taking into account mere translations and rotations between images,a contour phase correlation algorithm is used to realize the preliminary alignments of images,and the initial projective transformation matrices are obtained.Then,an optimization algorithm is used to optimize the initial projective transformation matrices,and complete the precise image mosaics.The contour phase correlation is an improvement on the conventional phase correlation in two aspects:First,the contours of images are extracted,and the phase correlation is applied to the contours of images instead of the whole original images;Second,when there are multiple peak values approximate to the maximum peak value in the δ function array,their corresponding translations can be regarded as candidate translations and calculated separately,and the best translation can be determined by the optimization of conformability of two images in the overlapping area.The running results show that the proposed algorithm can consistently yield high-quality mosaics,even in the cases of poor or differential lighting conditions,existences of minor rotations,and other complicated displacements between images.
Hou, Lei; Chen, Qijing; An, Zesheng; Wu, Peiyi
2016-02-28
The lower critical solution temperature (LCST) transition in water and the upper critical solution temperature (UCST) transition in ethanol of poly(oligo(ethylene glycol) acrylate) (POEGA)-based core cross-linked star (CCS) polymers have been investigated and compared by employing turbidity, dynamic light scattering (DLS), (1)H NMR and FTIR measurements. Macroscopic phase transitions in water and in ethanol were observed to occur when passing through the transition temperature, as revealed by DLS and turbidity measurements. Analysis by IR indicated that the interactions between the polymer chains and solvent molecules in water are stronger than those in ethanol such that the CCS polymer arm chains in water adopt more extended conformations. Moreover, hydrophobic interaction among the aliphatic groups plays a predominant role in the LCST-type transition in water whereas weak solvation of the polymer chains results in the UCST-type transition in ethanol. Additionally, the LCST-type transition in water was observed to be much more abrupt and complete than the UCST-type transition in ethanol, as suggested by (1)H NMR and IR at the molecular level. Finally, an abnormal "forced hydration" phenomenon was observed during the LCST transition upon heating. This study provides a detailed understanding of the subtle distinctions between the thermal transitions of CCS polymers in two commonly used solvents, which may be useful to guide future materials design for a wide range of applications.
Tekarli, Sammer M; Drummond, Michael L; Williams, T Gavin; Cundari, Thomas R; Wilson, Angela K
2009-07-30
The performance of 44 density functionals used in conjunction with the correlation consistent basis sets (cc-pVnZ where n = T and Q) has been assessed for the gas-phase enthalpies of formation at 298.15 K of 3d transition metal (TM) containing systems. Nineteen molecules were examined: ScS, VO, VO(2), Cr(CO)(6), MnS, MnCl(2), Mn(CO)(5)Cl, FeCl(3), Fe(CO)(5), CoH(CO)(4), NiCl(2), Ni(CO)(4), CuH, CuF, CuCl, ZnH, ZnO, ZnCl, and Zn(CH(3))(2). Of the functionals examined, the functionals that resulted in the smallest mean absolute deviation (MAD, in parentheses, kcal mol(-1)) from experiment were B97-1 (6.9), PBE1KCIS (8.1), TPSS1KCIS (9.6), B97-2 (9.7), and B98 (10.7). All five of these functionals include some degree of Hartree-Fock (HF) exchange. The impact of increasing the basis set from cc-pVTZ to cc-pVQZ was found to be slight for the generalized gradient approximation (GGA) and meta-GGA (MGGA) functionals studied, indicating basis set saturation at the triple-zeta level. By contrast, for most of the generalized gradient exchange (GGE), hybrid GGA (HGGA), and hybrid meta-GGA (HMGGA) functionals considered, improvements in the average MAD of 2-3 kcal mol(-1) were seen upon progressing to a quadruple-zeta level basis set. Overall, it was found that the functionals that include Hartree-Fock exchange performed best overall, but those with greater than 40% HF exchange exhibit significantly poor performance for the prediction of enthalpies of formation for 3d TM complexes. Carbonyl-containing complexes, a mainstay in organometallic TM chemistry, are demonstrated to be exceedingly difficult to describe accurately with all but 2 of the 44 functionals considered. The most accurate functional, for both CO-containing and CO-free compounds, is B97-1/cc-pVQZ, which is shown to be capable of yielding results within 1 kcal mol(-1) of high-level ab initio composite methodologies.
Measuring Acoustic Wave Transit Time in Furnace Based on Active Acoustic Source Signal
Institute of Scientific and Technical Information of China (English)
Zhen Luo; Feng Tian; Xiao-Ping Sun
2007-01-01
Accurate measurement of transit time for acoustic wave between two sensors installed on two sides of a furnace is a key to implementing the temperature field measurement technique based on acoustical method. A new method for measuring transit time of acoustic wave based on active acoustic source signal is proposed in this paper, which includes the followings: the time when the acoustic source signal arrives at the two sensors is measured first; then, the difference of two arriving time arguments is computed, thereby we get the transit time of the acoustic wave between two sensors installed on the two sides of the furnace. Avoiding the restriction on acoustic source signal and background noise, the new method can get the transit time of acoustic wave with higher precision and stronger ability of resisting noise interference.
AN AGENT—BASED SIMULATION ON MARKET CONSIDERING KNOWLEDGE TRANSITION AND SOCIAL IMPACT
Institute of Scientific and Technical Information of China (English)
Tieju; MinaRyoke; 等
2002-01-01
In this paper,an agent-based simulation about knowledge transition associated with social impact in market is introduced.In the simulation,the genetic algorthm is used to generate the next generation products and a dynamic social impact model is used to simulate how customers are influenced by other customers.The simulation and its results not only show some features and patterns of knowlege transition,but also explore and display some phenomena of business cultures.On the basis of the innovation model of knowledge-based economy,the transition between technical knowledge and products knowledge is discussed,and a fuzzy linear quantification model which can be used to simulate the transition is introduced.
Introducing Opportunity-based Entrepreneurship in a Transition Economy
DEFF Research Database (Denmark)
Perunovic, Zoran
2005-01-01
possible entrepreneurial settings for a selected town or region, and four strategies for introducing the opportunity-based entrepreneurship are given. In the most general sense, this paper strives to encourage discussion about national systems of innovation as a complementary and/or dominant catch...... either a necessity- or opportunity-based ntrepreneurial environment. The concluding remarks emphasize the need for careful introduction of opportunity-based entrepreneurship together with recommendations for how that may be accomplished across different regions. Results suggest that there are four...
Face Recognition of Illumination Tolerance in 2D Subspace Based on the Optimum Correlation Filter
National Research Council Canada - National Science Library
Yi Xu
2014-01-01
... subspace based on the optimal correlation filter. Firstly, through the use of a particular class 2D-PCA the face image is reconstructed and by using the optimum projecting image correlation filter (OPICF...
Sampling of general correlators in worm-algorithm based simulations
Directory of Open Access Journals (Sweden)
Tobias Rindlisbacher
2016-08-01
Full Text Available Using the complex ϕ4-model as a prototype for a system which is simulated by a worm algorithm, we show that not only the charged correlator 〈ϕ⁎(xϕ(y〉, but also more general correlators such as 〈|ϕ(x||ϕ(y|〉 or 〈arg(ϕ(xarg(ϕ(y〉, as well as condensates like 〈|ϕ|〉, can be measured at every step of the Monte Carlo evolution of the worm instead of on closed-worm configurations only. The method generalizes straightforwardly to other systems simulated by worms, such as spin or sigma models.
Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions.
Weng, Z F; Smidman, M; Jiao, L; Lu, Xin; Yuan, H Q
2016-09-01
Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.
Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions
Weng, Z. F.; Smidman, M.; Jiao, L.; Lu, Xin; Yuan, H. Q.
2016-09-01
Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.
2016-01-05
Nanolayer and two-dimensional (2D) materials 9 such as grapheme 10, 11, boron nitride 9, 12, transition metal dichalcogenides 9, 13-16 (TMDCs), and... plasma frequency ≈ 0.4pω eV, carrier density . 11 11 1 10 cm−≈ ×n and the thickness of the surface metallic layer of ~ 1 nm . We have also...observed similar behavior in other nanolayer semiconductors such as TMDC MoS2 and topological insulator Bi2Te3 but not in insulators such as boron nitride
Silveira, Camila Magalhães; Viana, Maria Carmen; Siu, Erica Rosanna; Guerra de Andrade, Arthur; Anthony, James C.; Andrade, Laura Helena
2011-01-01
Aims: To evaluate sociodemographic correlates associated with transitions from alcohol use to disorders and remission in a Brazilian population. Methods: Data are from a probabilistic, multi-stage clustered sample of adult household residents in the São Paulo Metropolitan Area. Alcohol use, regular use (at least 12 drinks/year), DSM-IV abuse and dependence and remission from alcohol use disorders (AUDs) were assessed with the World Mental Health version of the Composite International Diagnost...
Katanin, A. A.; Belozerov, A. S.; Anisimov, V. I.
2016-01-01
We consider nonlocal correlations in iron in the vicinity of the $\\alpha$-$\\gamma$ phase transition within the spin-rotationally-invariant dynamical mean-field theory (DMFT) approach, combined with the recently proposed spin-fermion model of iron. The obtained nonlocal corrections to DMFT yield a decrease of the Curie temperature of the $\\alpha$ phase, leading to an agreement with its experimental value. We show that the corresponding nonlocal corrections to the energy of the $\\alpha$ phase a...
Kepler and Ground-based Transits of the Exo-Neptune HAT-P-11b
Deming, Drake; Jackson, Brian; Peterson, Steven W; Agol, Eric; Knutson, Heather A; Jennings, Donald E; Haase, Flynn; Bays, Kevin
2011-01-01
We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B-band) and near-IR (J-band). Both the planet and host star are smaller than previously believed; our analysis yields Rp=4.31 +/-0.06 Earth-radii, and Rs = 0.683 +/-0.009 solar radii, both about 3-sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler tr...
CHAOTIC CONTROL OF NONLINEAR SYSTEMS BASED ON IMPROVED CORRELATIVITY
Institute of Scientific and Technical Information of China (English)
Zhou Xiaoan; Zhang Jihong
2003-01-01
Chaotic sequences are basically ergodic random sequences. By improving correlativity of a chaotic signal, the chaotic dynamic system can be controlled to converge to its equilibrium point and, more significantly, to its multi-periodic orbits. Mathematical theory analysis is carried out and some computer simulation results are provided to support such controllability of the chaotic Henon system and the discrete coupled map lattice.
Tests of Fit Based on the Correlation Coefficient
1990-10-04
function. Regional Conference Series in Appl. Math., 9. Philadelphia: SIAM. 2. Gerlach, B., (1979). A consistent correlation-type goodness-of-fit test; with...the distribution of quadratic forms in normal variables. Biometrika, 48, 419-426. 4. Sarkadi, K., (1975). The consistency of the Shapiro- Francia test
Chang, Catie; Glover, Gary H
2009-10-01
Previous studies have reported that the spontaneous, resting-state time course of the default-mode network is negatively correlated with that of the "task-positive network", a collection of regions commonly recruited in demanding cognitive tasks. However, all studies of negative correlations between the default-mode and task-positive networks have employed some form of normalization or regression of the whole-brain average signal ("global signal"); these processing steps alter the time series of voxels in an uninterpretable manner as well as introduce spurious negative correlations. Thus, the extent of negative correlations with the default mode network without global signal removal has not been well characterized, and it is has recently been hypothesized that the apparent negative correlations in many of the task-positive regions could be artifactually induced by global signal pre-processing. The present study aimed to examine negative and positive correlations with the default-mode network when model-based corrections for respiratory and cardiac noise are applied in lieu of global signal removal. Physiological noise correction consisted of (1) removal of time-locked cardiac and respiratory artifacts using RETROICOR (Glover, G.H., Li, T.Q., Ress, D., 2000. Image-based method for retrospective correction of physiological motion effects in fMRI: RETROICOR. Magn. Reson. Med. 44, 162-167), and (2) removal of low-frequency respiratory and heart rate variations by convolving these waveforms with pre-determined transfer functions (Birn et al., 2008; Chang et al., 2009) and projecting the resulting two signals out of the data. It is demonstrated that negative correlations between the default-mode network and regions of the task-positive network are present in the majority of individual subjects both with and without physiological noise correction. Physiological noise correction increased the spatial extent and magnitude of negative correlations, yielding negative
Equilibrium model and algorithm of urban transit assignment based on augmented network
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The passenger flow assignment problem for the urban transit network is relatively complicated due to the complexity of the network structure and many factors influencing the passengers’ route and line choices. In the past three decades, many models have been proposed to solve the passenger flow assignment problem. However, the common-line problem remains challenging in transit flow assignment. In this paper, the characteristics of the urban transit network is analysed and a new technique of augmented network is proposed to represent the urban transit system. The purpose is to eliminate the complex common-line problem when modeling transit passenger flow assignment. Through this augmentation technique, the urban transit system can be represented by an augmented network-it then behaves like a simple network and can be used as a generalized network for traffic assignment or network analysis. This paper presents a user equilibrium model for the urban transit assignment problem based on such a technique. A numerical example is also provided to illustrate the approach.
Laser transit anemometer measurements of a JANNAF nozzle base velocity flow field
Hunter, William W., Jr.; Russ, C. E., Jr.; Clemmons, J. I., Jr.
1990-01-01
Velocity flow fields of a nozzle jet exhausting into a supersonic flow were surveyed. The measurements were obtained with a laser transit anemometer (LTA) system in the time domain with a correlation instrument. The LTA data is transformed into the velocity domain to remove the error that occurs when the data is analyzed in the time domain. The final data is shown in velocity vector plots for positions upstream, downstream, and in the exhaust plane of the jet nozzle.
Language-Based Prior Knowledge and Transition to Mathematics
Dogan-Dunlap, Hamide; Torres, Cristina; Chen, Fan
2005-01-01
The paper provides a college mathematics student's concept maps, definitions, and essays to support the thesis that language-based prior knowledge can influence students' cognitive processes of mathematical concepts. A group of intermediate algebra students who displayed terms mainly from the spoken language on the first and the second concept…
Transition from School-Based Training in VET
Daehlen, Marianne
2017-01-01
Purpose: This paper assesses the drop-out rate among disadvantaged students within vocational education and training. The purpose of this paper is to examine the probability of dropping out after school-based training for child welfare clients--a particularly disadvantaged group of youth. Child welfare clients' drop-out rate is compared with…
Lee, Jun-Yi; Huang, -Chuan, Jr.
2017-04-01
Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.
Challenges and opportunities for transition to knowledge-based economy in Arab Gulf countries
Nour, S.
2014-01-01
This paper uses the descriptive and comparative approaches and uses the OECD (1996) definition of knowledge-based economy, the World Bank Knowledge Index and Knowledge Economy Index and other indicators to examine progress and challenges in transition to knowledge-based economies in Arab Gulf countr
Generation of chaotic oscillations in auto-oscillator based on avalanche transit-time diode
Myasin, E. A.
2012-01-01
Time series of chaotic oscillations have been observed for the first time in an auto-oscillator for the 8-mm wavelength range based on an avalanche transit-time diode. The noise generator based on this diode has been used as a signal source for a noise radar prototype.
NIRS-BASED CORTICAL ACTIVATION ANALYSIS BY TEMPORAL CROSS CORRELATION
Directory of Open Access Journals (Sweden)
Raul Fernandez-Rojas
2016-02-01
Full Text Available In this study we present a method of signal processing to determine dominant channels in near infrared spectroscopy (NIRS. To compare measuring channels and identify delays between them, cross correlation is computed. Furthermore, to find out possible dominant channels, a visual inspection was performed. The outcomes demonstrated that the visual inspection exhibited evoked-related activations in the primary somatosensory cortex (S1 after stimulation which is consistent with comparable studies and the cross correlation study discovered dominant channels on both cerebral hemispheres. The analysis also showed a relationship between dominant channels and adjacent channels. For that reason, our results present a new method to identify dominant regions in the cerebral cortex using near-infrared spectroscopy. These findings have also implications in the decrease of channels by eliminating irrelevant channels for the experiment.
Malfunction diagnosis of sensors based on correlation of measurements
Lu, Wei; Teng, Jun; Wen, Runfa; Zhu, Jiayi; Li, Chao
2017-02-01
Structural health monitoring (SHM) is a type of on-site characterization of a real-world full-scale structure that is subjected to the real-world load cases. The fundamental element of SHM is the structural response measurements by sensors, the reliability of which is significant for safety assessment and other SHM applications. The paper proposed a method to diagnosis the fault in sensors using the correlation of measurements. The correlation of the variations of the measurements is examined using the sliding time windows, which is the principle to determine the fault in the sensors. The strain measurements from the SHM system of a real world structure, Shenzhen Bay Stadium, are performed to simulate the faults in sensors and to verify the effectiveness of the proposed method.
Directory of Open Access Journals (Sweden)
Maria A. Komkova
2013-10-01
Full Text Available We report here a way for improving the stability of ultramicroelectrodes (UME based on hexacyanoferrate-modified metals for the detection of hydrogen peroxide. The most stable sensors were obtained by electrochemical deposition of six layers of hexacyanoferrates (HCF, more specifically, an alternating pattern of three layers of Prussian Blue and three layers of Ni–HCF. The microelectrodes modified with mixed layers were continuously monitored in 1 mM hydrogen peroxide and proved to be stable for more than 5 h under these conditions. The mixed layer microelectrodes exhibited a stability which is five times as high as the stability of conventional Prussian Blue-modified UMEs. The sensitivity of the mixed layer sensor was 0.32 A·M−1·cm−2, and the detection limit was 10 µM. The mixed layer-based UMEs were used as sensors in scanning electrochemical microscopy (SECM experiments for imaging of hydrogen peroxide evolution.
Meigas, Kalju; Lass, Jaanus; Kattai, Rain; Karai, Deniss; Kaik, Juri
2004-07-01
This paper is a part of research to develop convenient method for continuous monitoring of arterial blood pressure by non-invasive and non-oscillometric way. A simple optical method, using self-mixing in a diode laser, is used for detection of skin surface vibrations near the artery. These vibrations, which can reveal the pulsate propagation of blood pressure waves along the vasculature, are used for pulse wave registration. The registration of the Pulse Wave Transit Time (PWTT) is based on computing the time delay in different regions of the human body using an ECG as a reference signal. In this study, the comparison of method of optical self-mixing with other methods as photoplethysmographic (PPG) and bioimpedance (BI) for PWTT is done. Also correlation of PWTT, obtained with different methods, with arterial blood pressure is calculated. In our study, we used a group of volunteers (34 persons) who made the bicycle exercise test. The test consisted of cycling sessions of increasing workloads during which the HR changed from 60 to 180 beats per minute. In addition, a blood pressure (NIBP) was registered with standard sphygmomanometer once per minute during the test and all NIBP measurement values were synchronized to other signals to find exact time moments where the systolic blood pressure was detected (Korotkoff sounds starting point). Computer later interpolated the blood pressure signal in order to get individual value for every heart cycle. The other signals were measured continuously during all tests. At the end of every session, a recovery period was included until person's NIBP and heart rate (HR) normalized. As a result of our study it turned out that time intervals that were calculated from plethysmographic (PPG) waveforms were in the best correlation with systolic blood pressure. The diastolic pressure does not correlate with any of the parameters representing PWTT. The pulse wave signals measured by laser and piezoelectric transducer are very similar
Tehsin, Sara; Rehman, Saad; Awan, Ahmad B.; Chaudry, Qaiser; Abbas, Muhammad; Young, Rupert; Asif, Afia
2016-04-01
Sensitivity to the variations in the reference image is a major concern when recognizing target objects. A combinational framework of correlation filters and logarithmic transformation has been previously reported to resolve this issue alongside catering for scale and rotation changes of the object in the presence of distortion and noise. In this paper, we have extended the work to include the influence of different logarithmic bases on the resultant correlation plane. The meaningful changes in correlation parameters along with contraction/expansion in the correlation plane peak have been identified under different scenarios. Based on our research, we propose some specific log bases to be used in logarithmically transformed correlation filters for achieving suitable tolerance to different variations. The study is based upon testing a range of logarithmic bases for different situations and finding an optimal logarithmic base for each particular set of distortions. Our results show improved correlation and target detection accuracies.
CHAOTIC CONTROL OF NONLINEAR SYSTEMS BASED ON IMPROVED CORRELATIVITY
Institute of Scientific and Technical Information of China (English)
ZhouZiaoan; ZhangJihong
2003-01-01
Chaotic sequences are basically ergodic random esquences.By improving correlativity of a chaotic signal,the chaotic dynamic system can be controlled to converge to its equilibrium point and,more significantly,to its multi-periodic orbits.Mathematical theory analysis is carried out and some computer simulation results are provided to support such controllability of the chaotic Henon system and the discrete coupled map lattice.
Extracting Coherent Information from Noise Based Correlation Processing
2015-09-30
LONG-TERM GOALS The goal of this research is to establish methodologies to utilize ambient noise in the ocean and to determine what scenarios...None PUBLICATIONS [1] “ Monitoring deep-ocean temperatures using acoustic ambinet noise,”K. W. Woolfe, S. Lani, K.G. Sabra, W. A. Kuperman...Geophys. Res. Lett., 42,2878–2884, doi:10.1002/2015GL063438 (2015). [2] “Optimized extraction of coherent arrivals from ambient noise correlations in
Stochastic User Equilibrium Assignment in Schedule-Based Transit Networks with Capacity Constraints
Directory of Open Access Journals (Sweden)
Wangtu Xu
2012-01-01
Full Text Available This paper proposes a stochastic user equilibrium (SUE assignment model for a schedule-based transit network with capacity constraint. We consider a situation in which passengers do not have the full knowledge about the condition of the network and select paths that minimize a generalized cost function encompassing five components: (1 ride time, which is composed of in-vehicle and waiting times, (2 overload delay, (3 fare, (4 transfer constraints, and (5 departure time difference. We split passenger demands among connections which are the space-time paths between OD pairs of the network. All transit vehicles have a fixed capacity and operate according to some preset timetables. When the capacity constraint of the transit line segment is reached, we show that the Lagrange multipliers of the mathematical programming problem are equivalent to the equilibrium passenger overload delay in the congested transit network. The proposed model can simultaneously predict how passengers choose their transit vehicles to minimize their travel costs and estimate the associated costs in a schedule-based congested transit network. A numerical example is used to illustrate the performance of the proposed model.
A tour-based analysis of travel mode choice accounting for regional transit service
Institute of Scientific and Technical Information of China (English)
丁川; 林姚宇; 谢秉磊; 朱晓雨
2015-01-01
The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area. With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington−Baltimore Household Travel Survey in 2007, including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors. This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.
Stochastic quantum Zeno-based detection of noise correlations
Müller, Matthias M.; Gherardini, Stefano; Caruso, Filippo
2016-12-01
A system under constant observation is practically freezed to the measurement subspace. If the system driving is a random classical field, the survival probability of the system in the subspace becomes a random variable described by the Stochastic Quantum Zeno Dynamics (SQZD) formalism. Here, we study the time and ensemble average of this random survival probability and demonstrate how time correlations in the noisy environment determine whether the two averages do coincide or not. These environment time correlations can potentially generate non-Markovian dynamics of the quantum system depending on the structure and energy scale of the system Hamiltonian. We thus propose a way to detect time correlations of the environment by coupling a quantum probe system to it and observing the survival probability of the quantum probe in a measurement subspace. This will further contribute to the development of new schemes for quantum sensing technologies, where nanodevices may be exploited to image external structures or biological molecules via the surface field they generate.
Chord Recognition Based on Temporal Correlation Support Vector Machine
Directory of Open Access Journals (Sweden)
Zhongyang Rao
2016-05-01
Full Text Available In this paper, we propose a method called temporal correlation support vector machine (TCSVM for automatic major-minor chord recognition in audio music. We first use robust principal component analysis to separate the singing voice from the music to reduce the influence of the singing voice and consider the temporal correlations of the chord features. Using robust principal component analysis, we expect the low-rank component of the spectrogram matrix to contain the musical accompaniment and the sparse component to contain the vocal signals. Then, we extract a new logarithmic pitch class profile (LPCP feature called enhanced LPCP from the low-rank part. To exploit the temporal correlation among the LPCP features of chords, we propose an improved support vector machine algorithm called TCSVM. We perform this study using the MIREX’09 (Music Information Retrieval Evaluation eXchange Audio Chord Estimation dataset. Furthermore, we conduct comprehensive experiments using different pitch class profile feature vectors to examine the performance of TCSVM. The results of our method are comparable to the state-of-the-art methods that entered the MIREX in 2013 and 2014 for the MIREX’09 Audio Chord Estimation task dataset.
From time-based to competency-based standards: core transitional competencies in plastic surgery.
Lutz, Kristina; Yazdani, Arjang; Ross, Douglas
2015-01-01
Competency-based medical education is becoming increasingly prevalent and is likely to be mandated by the Royal College in the near future. The objective of this study was to define the core technical competencies that should be possessed by plastic surgery residents as they transition into their senior (presently postgraduate year 3) years of training. A list of potential core competencies was generated using a modified Delphi method that included the investigators and 6 experienced, academic plastic surgeons from across Canada and the United States. Generated items were divided into 7 domains: basic surgical skills, anesthesia, hand surgery, cutaneous surgery, esthetic surgery, breast surgery, and craniofacial surgery. Members of the Delphi group were asked to rank particular skills on a 4-point scale with anchored descriptors. Item reduction resulted in a survey consisting of 48 skills grouped into the aforementioned domains. This self-administered survey was distributed to all Canadian program directors (n = 11) via e-mail for validation and further item reduction. The response rate was 100% (11/11). Using the average rankings of program directors, 26 "core" skills were identified. There was agreement of core skills across all domains except for breast surgery and esthetic surgery. Of them, 7 skills were determined to be above the level of a trainee at this stage; a further 15 skills were agreed to be important, but not core, competencies. Overall, 26 competencies have been identified as "core" for plastic surgery residents to possess as they begin their senior, on-service years. The nature of these skills makes them suitable for teaching in a formal, simulated environment, which would ensure that all plastic surgery trainees are competent in these tasks as they transition to their senior years of residency. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.
Jin, Anshu; Aki, Keiiti
1993-07-01
Analysis of local earthquake coda waves recorded on Wood-Anderson (1940-1947) and Benioff (after 1947) short-period vertical seismographs at station Mt. Hamilton, Calif., revealed a large temporal variation in coda Q-1. A strong positive correlation was found between the temporal variation of coda Q-1 and the number of earthquakes with a magnitude of 4.0⩽ M⩽4.5 appearing in a series of 100 consecutive earthquakes with a magnitude M⩾3.0. A correlation coefficient of 0.84 was determined with a confidence level of 0.98. The amplitude and time constant of variation in coda Q-1 for central California are similar to those found earlier for southern California (Jin and Aki, 1989). The strong correlation between coda Q-1 and b-value reported by Jin and Aki (1989) was shown to be equivalent to a positive correlation between coda Q-1 and the fractional number of earthquakes with a magnitude 3.0⩽ M⩽3.5. A review of the literature reporting observed temporal correlation between coda Q-1 and b-value (both positive and negative) revealed that all the reported observations can be interpreted in terms of a positive correlation between the coda Q-1 and the fractional frequency of earthquakes in a magnitude range around a certain magnitude, Mc, characteristic to each region. This positive correlation has been attributed to the aseismic creep in the brittle-ductile transition zone. Aseismic creep in the transition zone may occur over fractures with a characteristic size for each region. The existence of fractures with a characteristic size would necessarily violate the scale independent self-similarity of earthquake phenomena. This is consistent with the growing literature demonstrating a departure from self-similarity in various seismic phenomena.
Efficacy of a Transition Theory-Based Discharge Planning Program for Childhood Asthma Management.
Ekim, Ayfer; Ocakci, Ayse Ferda
2016-02-01
This study tested the efficacy of a nurse-led discharge planning program for childhood asthma management, based on transition theory. A quasi-experimental design was used. The sample comprised 120 children with asthma and their parents (intervention group n = 60, control group n = 60). The asthma management self-efficacy perception level of parents in the intervention group increased significantly and the number of triggers their children were exposed to at home was reduced by 60.8%. The rates of admission to emergency departments and unscheduled outpatient visits were significantly lower in the intervention group compared with the control group. Transition theory-based nursing interventions can provide successful outcomes on childhood asthma management. Transition theory-based discharge planning program can guide nursing interventions to standardize care of the child with asthma. Combining care at home with hospital care strengthens ongoing qualified asthma management. © 2015 NANDA International, Inc.
Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation
Pan, Bing
2015-02-12
Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.
Color pattern recognition based on the joint fractional Fourier transform correlator
Institute of Scientific and Technical Information of China (English)
Weimin Jin; Yupei Zhang
2007-01-01
A new system of multi-channel single-output joint fractional Fourier transform correlator (JFRTC) for color pattern recognition is proposed based on the conventional system of multi-channel single-output joint transform correlator (JTC). The theoretical analysis and optical experiments are performed. With this method, one can obtain three correlation peaks at the output plane which show a pair of desired cross-correlation peaks and one auto-correlation peak. In comparison, the conventional system leads to more correlation peaks playing a noise role in color pattern recognition.
Li, Fei; Choudhari, Meelan M.; Carpenter, Mark H.; Malik, Mujeeb R.; Eppink, Jenna; Chang, Chau-Lyan; Streett, Craig L.
2010-01-01
A high fidelity transition prediction methodology has been applied to a swept airfoil design at a Mach number of 0.75 and chord Reynolds number of approximately 17 million, with the dual goal of an assessment of the design for the implementation and testing of roughness based crossflow transition control and continued maturation of such methodology in the context of realistic aerodynamic configurations. Roughness based transition control involves controlled seeding of suitable, subdominant crossflow modes in order to weaken the growth of naturally occurring, linearly more unstable instability modes via a nonlinear modification of the mean boundary layer profiles. Therefore, a synthesis of receptivity, linear and nonlinear growth of crossflow disturbances, and high-frequency secondary instabilities becomes desirable to model this form of control. Because experimental data is currently unavailable for passive crossflow transition control for such high Reynolds number configurations, a holistic computational approach is used to assess the feasibility of roughness based control methodology. Potential challenges inherent to this control application as well as associated difficulties in modeling this form of control in a computational setting are highlighted. At high Reynolds numbers, a broad spectrum of stationary crossflow disturbances amplify and, while it may be possible to control a specific target mode using Discrete Roughness Elements (DREs), nonlinear interaction between the control and target modes may yield strong amplification of the difference mode that could have an adverse impact on the transition delay using spanwise periodic roughness elements.
Han, Xiang-Bin; Hu, Pan; Shi, Chao; Zhang, Wen
2017-01-01
1,4-Diazabicyclo[2.2.2]octane (dabco) based organic crystal [(Hdabco)(H2O)](PF6) (1) was synthesized and characterized. Its structure is featured by wavy-like one-dimensional supramolecular hydrogen bond chains built from the [(Hdabco)(H2O)] units from end to end. Compound 1 undergoes two reversible phase transitions at 226/268 K and 178/181 K, respectively. The disorder-order transition of water molecule in the hydrogen bond chain induces the phase transition at 226 K while the twisting of the [Hdabco]+ cation and displacements of the PF6- anion and H2O molecules trigger the phase transition at 178 K. Dielectric transitions are thus triggered in the crystal.
Nonlinear ultrasonic measurements based on cross-correlation filtering techniques
Yee, Andrew; Stewart, Dylan; Bunget, Gheorghe; Kramer, Patrick; Farinholt, Kevin; Friedersdorf, Fritz; Pepi, Marc; Ghoshal, Anindya
2017-02-01
Cyclic loading of mechanical components promotes the formation of dislocation dipoles in metals, which can serve as precursors to crack nucleation and ultimately lead to failure. In the laboratory setting, an acoustic nonlinearity parameter has been assessed as an effective indicator for characterizing the progression of fatigue damage precursors. However, the need to use monochromatic waves of medium-to-high acoustic energy has presented a constraint, making it problematic for use in field applications. This paper presents a potential approach for field measurement of acoustic nonlinearity by using general purpose ultrasonic pulser-receivers. Nonlinear ultrasonic measurements during fatigue testing were analyzed by the using contact and immersion pulse-through method. A novel cross-correlation filtering technique was developed to extract the fundamental and higher harmonic waves from the signals. As in the case of the classic harmonic generation, the nonlinearity parameters of the second and third harmonics indicate a strong correlation with fatigue cycles. Consideration was given to potential nonlinearities in the measurement system, and tests have confirmed that measured second harmonic signals exhibit a linear dependence on the input signal strength, further affirming the conclusion that this parameter relates to damage precursor formation from cyclic loading.
Correlation based efficient face recognition and color change detection
Elbouz, M.; Alfalou, A.; Brosseau, C.; Alam, M. S.; Qasmi, S.
2013-01-01
Identifying the human face via correlation is a topic attracting widespread interest. At the heart of this technique lies the comparison of an unknown target image to a known reference database of images. However, the color information in the target image remains notoriously difficult to interpret. In this paper, we report a new technique which: (i) is robust against illumination change, (ii) offers discrimination ability to detect color change between faces having similar shape, and (iii) is specifically designed to detect red colored stains (i.e. facial bleeding). We adopt the Vanderlugt correlator (VLC) architecture with a segmented phase filter and we decompose the color target image using normalized red, green, and blue (RGB), and hue, saturation, and value (HSV) scales. We propose a new strategy to effectively utilize color information in signatures for further increasing the discrimination ability. The proposed algorithm has been found to be very efficient for discriminating face subjects with different skin colors, and those having color stains in different areas of the facial image.
Aron, Allegra T; Ramos-Torres, Karla M; Cotruvo, Joseph A; Chang, Christopher J
2015-08-18
Metals are essential for life, playing critical roles in all aspects of the central dogma of biology (e.g., the transcription and translation of nucleic acids and synthesis of proteins). Redox-inactive alkali, alkaline earth, and transition metals such as sodium, potassium, calcium, and zinc are widely recognized as dynamic signals, whereas redox-active transition metals such as copper and iron are traditionally thought of as sequestered by protein ligands, including as static enzyme cofactors, in part because of their potential to trigger oxidative stress and damage via Fenton chemistry. Metals in biology can be broadly categorized into two pools: static and labile. In the former, proteins and other macromolecules tightly bind metals; in the latter, metals are bound relatively weakly to cellular ligands, including proteins and low molecular weight ligands. Fluorescent probes can be useful tools for studying the roles of transition metals in their labile forms. Probes for imaging transition metal dynamics in living systems must meet several stringent criteria. In addition to exhibiting desirable photophysical properties and biocompatibility, they must be selective and show a fluorescence turn-on response to the metal of interest. To meet this challenge, we have pursued two general strategies for metal detection, termed "recognition" and "reactivity". Our design of transition metal probes makes use of a recognition-based approach for copper and nickel and a reactivity-based approach for cobalt and iron. This Account summarizes progress in our laboratory on both the development and application of fluorescent probes to identify and study the signaling roles of transition metals in biology. In conjunction with complementary methods for direct metal detection and genetic and/or pharmacological manipulations, fluorescent probes for transition metals have helped reveal a number of principles underlying transition metal dynamics. In this Account, we give three recent
The transition to competency-based pediatric training in the United Arab Emirates.
Ibrahim, Halah; Al Tatari, Hossam; Holmboe, Eric S
2015-04-01
Although competency-based medical education has become the standard for physician training in the West, many developing countries have not yet adopted competency-based training. In 2009 in the United Arab Emirates, the government regulatory and operational authorities for healthcare in Abu Dhabi mandated a wide-scale reform of the emirate's postgraduate residency programs to the competency-based framework of the newly formed Accreditation Council for Graduate Medical Education-International (ACGME-I). This article briefly describes the rationale for competency-based medical education and provides an overview of the transition from traditional, time-based residency training to competency-based postgraduate medical education for the Pediatrics residency programs in Abu Dhabi. We will provide data on the initial impact of this transition on resident performance and patient outcomes in a Pediatrics residency program in an academic medical center in the United Arab Emirates.
Examining "success" in post-hip fracture care transitions: a strengths-based approach.
Sims-Gould, Joanie; Byrne, Kerry; Hicks, Elisabeth; Khan, Karim; Stolee, Paul
2012-05-01
Transitions between health care settings are a high-risk period for care quality and patient safety (Coleman, 2003; Picker Institute, 1999), particularly for older patients - such as those with hip fracture - who have complex needs and may undergo multiple care transitions. We sought to understand the key elements of "success" in care transition. Using a strengths-based perspective (Rapp, 1998; Saleebey, 2006), we focused on interprofessional health care providers' perspectives of what constitutes a "good" care transition for elderly hip fracture patients. As part of a larger ethnographic field study, semi-structured interviews were conducted with 17 health providers across a number of disciplines employed across the continuum of post-hip fracture management in British Columbia, Canada. We found two hallmarks of "success" in care transitions: a focus on process - information gathering and communication, and a focus on outcomes - autonomy and care pathways. Strategies for promoting and improving success, such as using practitioner-driven ground-up solutions to address challenges in care transitions, are highlighted.
Ecosystem Based Management in Transition: From Ocean Policy to Application
Saumweber, W. J.; Goldman, E.
2016-12-01
Ecosystem-based management (EBM) has been proposed as a means to improve resource management and stewardship for more than two decades. Over this history, its exact goals and approaches have evolved in concert with advances in science and policy, including a greater understanding of ecosystem function, valuation, and thresholds for change, along with direct reference to EBM principles in statute, regulation, and other Executive Actions. Most recently, and explicitly, the Administration's National Ocean Policy (NOP) called for the development of a Federal EBM framework that would outline principles and guidelines for implementing EBM under existing authorities. This cross-agency framework has yet to be developed, but, the NOP, and related Administration initiatives, have resulted in the practical application of EBM principles in several issue-specific policy initiatives ranging from fisheries and marine protected area management to coastal adaptation and water resource infrastructure investment. In each case, the application of EBM principles uses apparently unique policy mechanisms (e.g. marine planning, ecosystem services assessment, adaptive management, dynamic ocean management, etc.). Despite differences in terminology and policy context, each of these policy initiatives is linked at its core to concepts of integrated and adaptive management that consider broad ecosystem function and services. This practical history of EBM implementation speaks to both the challenges and opportunities in broad incorporation of EBM across diverse policy initiatives and frameworks. We suggest that the continued growth of EBM as a practical policy concept will require a move away from broad frameworks, and towards the identification of specific resource management issues and accompanying policy levers with which to address those issues. In order to promote this progression, Federal policy should recognize and articulate the diverse set of policy mechanisms encompassed under the
Torchinsky, Darius H.; Johnson, Jeremy A.; Nelson, Keith A.
2009-02-01
We present an impulsive stimulated scattering test of the "shoving model" of the glass transition and of the correlation between the fragility index and the ratio of instantaneous elastic moduli of eight supercooled liquids. Samples of triphenyl phosphite, DC704 (tetramethyl tetraphenyl trisiloxane), m-fluoroaniline, Ca(NO3)2ṡ4H2O, diethyl phthalate, propylene carbonate, m-toluidine, phenyl salicylate (salol), 2-benzylphenol, and Santovac 5 (5-phenyl 4-ether), were cooled to their respective glass transition temperatures and the elastic moduli directly measured at the highest accessible shear frequencies. The shear modulus was then measured every 2 K as deeply as permitted into the liquid state for all liquids except propylene carbonate. Our results, in conjunction with dynamical relaxation data for these liquids obtained from the literature, lend credence to the notion that the dynamics of the glass transition are governed by the evolution of the shear modulus but do not suggest a strong correlation between the fragility index and the ratio of the elastic moduli.
Narayanan, Sreekala; Mitra, Gopa; Muralidharan, Monita; Mathew, Boby; Mandal, Amit K
2015-12-01
To gain insight into the underlying mechanisms of various biological events, it is important to study the structure-function correlation of proteins within cells. Structural probes used in spectroscopic tools to investigate protein conformation are similar across all proteins. Therefore, structural studies are restricted to purified proteins in vitro and these findings are extrapolated in cells to correlate their functions in vivo. However, due to cellular complexity, in vivo and in vitro environments are radically different. Here, we show a novel way to monitor the structural transition of human hemoglobin upon oxygen binding in living red blood cells (RBCs), using hydrogen/deuterium exchange-based mass spectrometry (H/DX-MS). Exploiting permeability of D2O across cell membrane, the isotope exchange of polypeptide backbone amide hydrogens of hemoglobin was carried out inside RBCs and monitored using matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). To explore the conformational transition associated with oxygenation of hemoglobin in vivo, the isotope exchange kinetics was simplified using the method of initial rates. RBC might be considered as an in vivo system of pure hemoglobin. Thus, as a proof-of-concept, the observed results were correlated with structural transition of hemoglobin associated with its function established in vitro. This is the first report on structural changes of a protein upon ligand binding in its endogenous environment. The proposed method might be applicable to proteins in their native state, irrespective of location, concentration, and size. The present in-cell approach opens a new avenue to unravel a plethora of biological processes like ligand binding, folding, and post-translational modification of proteins in living cells.
An optimized, universal hardware-based adaptive correlation receiver architecture
Zhu, Zaidi; Suarez, Hernan; Zhang, Yan; Wang, Shang
2014-05-01
The traditional radar RF transceivers, similar to communication transceivers, have the basic elements such as baseband waveform processing, IF/RF up-down conversion, transmitter power circuits, receiver front-ends, and antennas, which are shown in the upper half of Figure 1. For modern radars with diversified and sophisticated waveforms, we can frequently observe that the transceiver behaviors, especially nonlinear behaviors, are depending on the waveform amplitudes, frequency contents and instantaneous phases. Usually, it is a troublesome process to tune an RF transceiver to optimum when different waveforms are used. Another issue arises from the interference caused by the waveforms - for example, the range side-lobe (RSL) caused by the waveforms, once the signals pass through the entire transceiver chain, may be further increased due to distortions. This study is inspired by the two existing solutions from commercial communication industry, digital pre-distortion (DPD) and adaptive channel estimation and Interference Mitigation (AIM), while combining these technologies into a single chip or board that can be inserted into the existing transceiver system. This device is then named RF Transceiver Optimizer (RTO). The lower half of Figure 1 shows the basic element of RTO. With RTO, the digital baseband processing does not need to take into account the transceiver performance with diversified waveforms, such as the transmitter efficiency and chain distortion (and the intermodulation products caused by distortions). Neither does it need to concern the pulse compression (or correlation receiver) process and the related mitigation. The focus is simply the information about the ground truth carried by the main peak of correlation receiver outputs. RTO can be considered as an extension of the existing calibration process, while it has the benefits of automatic, adaptive and universal. Currently, the main techniques to implement the RTO are the digital pre- or -post
Chen, Yimin; Mu, Sen; Wang, Guoxiang; Shen, Xiang; Wang, Junqiang; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua; Wang, Rongping
2017-10-01
Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5 and GeTe are marginal glass formers with ΔT (= T x ‑ T g) less than 2.1 °C when the heating rate is below 3 °C min‑1. The fragilities of Ge2Sb2Te5 and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.
A Net Energy-based Analysis for a Climate-constrained Sustainable Energy Transition
Sgouridis, Sgouris; Csala, Denes
2015-01-01
The transition from a fossil-based energy economy to one based on renewable energy is driven by the double challenge of climate change and resource depletion. Building a renewable energy infrastructure requires an upfront energy investment that subtracts from the net energy available to society. This investment is determined by the need to transition to renewable energy fast enough to stave off the worst consequences of climate change and, at the same time, maintain a sufficient net energy flow to sustain the world's economy and population. We show that a feasible transition pathway requires that the rate of investment in renewable energy should accelerate approximately by an order of magnitude if we are to stay within the range of IPCC recommendations.
Prevalence and Correlates of Gender-based Violence among ...
African Journals Online (AJOL)
Erah
Keywords: Gender-based violence female university students. Introduction ... The university has a total of eight faculties and two schools. The ..... same vein, those in the faculty of social and .... with mode of dressing and closer interactions with.
Directory of Open Access Journals (Sweden)
Lara Nasreddine
2017-03-01
Full Text Available There is increasing evidence linking early life adiposity to disease risk later in life. This study aims at determining the prevalence and correlates of overweight and obesity among preschoolers in Lebanon. A national cross-sectional survey was conducted amongst 2–5 years old children (n = 525. Socio-demographic, lifestyle, dietary, and anthropometric data were obtained. The prevalence of overweight and obesity was estimated at 6.5% and 2.7%, respectively. Based on stepwise logistic regression for the prediction of overweight and obesity (combined, the variance accounted for by the first block (socioeconomic, parental characteristics was 11.9%, with higher father’s education (OR = 5.31, 95% CI: 1.04–27.26 and the presence of household helper (OR = 2.19, 95% CI: 1.05–4.56 being significant predictors. The second block of variables (eating habits significantly improved the prediction of overweight/obesity to reach 21%, with eating in front of the television (OR = 1.07, 95% CI: 1.02–1.13 and satiety responsiveness (OR = 0.83, 95% CI: 0.70–0.99 being significantly associated with overweight/obesity. In the third block, fat intake remained a significant predictor of overweight/obesity (OR = 2.31, 95% CI: 1.13–4.75. This study identified specific risk factors for preschool overweight/obesity in Lebanon and characterized children from high socioeconomic backgrounds as important target groups for preventive interventions. These findings may be of significance to other middle-income countries in similar stages of nutrition transition.
Nasreddine, Lara; Hwalla, Nahla; Saliba, Angie; Akl, Christelle; Naja, Farah
2017-01-01
There is increasing evidence linking early life adiposity to disease risk later in life. This study aims at determining the prevalence and correlates of overweight and obesity among preschoolers in Lebanon. A national cross-sectional survey was conducted amongst 2–5 years old children (n = 525). Socio-demographic, lifestyle, dietary, and anthropometric data were obtained. The prevalence of overweight and obesity was estimated at 6.5% and 2.7%, respectively. Based on stepwise logistic regression for the prediction of overweight and obesity (combined), the variance accounted for by the first block (socioeconomic, parental characteristics) was 11.9%, with higher father’s education (OR = 5.31, 95% CI: 1.04–27.26) and the presence of household helper (OR = 2.19, 95% CI: 1.05–4.56) being significant predictors. The second block of variables (eating habits) significantly improved the prediction of overweight/obesity to reach 21%, with eating in front of the television (OR = 1.07, 95% CI: 1.02–1.13) and satiety responsiveness (OR = 0.83, 95% CI: 0.70–0.99) being significantly associated with overweight/obesity. In the third block, fat intake remained a significant predictor of overweight/obesity (OR = 2.31, 95% CI: 1.13–4.75). This study identified specific risk factors for preschool overweight/obesity in Lebanon and characterized children from high socioeconomic backgrounds as important target groups for preventive interventions. These findings may be of significance to other middle-income countries in similar stages of nutrition transition. PMID:28287459
Nasreddine, Lara; Hwalla, Nahla; Saliba, Angie; Akl, Christelle; Naja, Farah
2017-03-11
There is increasing evidence linking early life adiposity to disease risk later in life. This study aims at determining the prevalence and correlates of overweight and obesity among preschoolers in Lebanon. A national cross-sectional survey was conducted amongst 2-5 years old children (n = 525). Socio-demographic, lifestyle, dietary, and anthropometric data were obtained. The prevalence of overweight and obesity was estimated at 6.5% and 2.7%, respectively. Based on stepwise logistic regression for the prediction of overweight and obesity (combined), the variance accounted for by the first block (socioeconomic, parental characteristics) was 11.9%, with higher father's education (OR = 5.31, 95% CI: 1.04-27.26) and the presence of household helper (OR = 2.19, 95% CI: 1.05-4.56) being significant predictors. The second block of variables (eating habits) significantly improved the prediction of overweight/obesity to reach 21%, with eating in front of the television (OR = 1.07, 95% CI: 1.02-1.13) and satiety responsiveness (OR = 0.83, 95% CI: 0.70-0.99) being significantly associated with overweight/obesity. In the third block, fat intake remained a significant predictor of overweight/obesity (OR = 2.31, 95% CI: 1.13-4.75). This study identified specific risk factors for preschool overweight/obesity in Lebanon and characterized children from high socioeconomic backgrounds as important target groups for preventive interventions. These findings may be of significance to other middle-income countries in similar stages of nutrition transition.
Collective multipole excitations based on correlated realistic nucleon-nucleon interactions
Energy Technology Data Exchange (ETDEWEB)
Paar, N. [Zagreb Univ. (Croatia). Fac. of Science, Physics Dept.; Papakonstantinou, P.; Hergert, H.; Roth, R. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik
2006-05-24
We investigate collective multipole excitations for closed shell nuclei from {sup 16}O to {sup 208}Pb using correlated realistic nucleon-nucleon interactions in the framework of the random phase approximation (RPA). The dominant short-range central and tensor correlations a re treated explicitly within the Unitary Correlation Operator Method (UCOM), which provides a phase-shift equivalent correlated interaction VUCOM adapted to simple uncorrelated Hilbert spaces. The same unitary transformation that defines the correlated interaction is used to derive correlated transition operators. Using VUCOM we solve the Hartree-Fock problem and employ the single-particle states as starting point for the RPA. By construction, the UCOM-RPA is fully self-consistent, i.e. the same correlated nucleon-nucleon interact ion is used in calculations of the HF ground state and in the residual RPA interaction. Consequently, the spurious state associated with the center-of-mass motion is properly removed and the sum-rules are exhausted within {+-}3%. The UCOM-RPA scheme results in a collective character of giant monopole, dipole, and quadrupole resonances in closed-shell nuclei across the nuclear chart. For the isoscalar giant monopole resonance, the resonance energies are in agreement with experiment hinting at a reasonable compressibility. However, in the 1{sup -} and 2{sup +} channels the resonance energies are overestimated due to missing long-range correlations and three-body contributions. (orig.)
Liechty, Derek S.; Lewis, Mark
2010-01-01
A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.
Chiu, Ying-Nan
1983-05-01
A new cyclic boundary condition which corresponds to a Möbius strip representation of a one-dimensional crystal is introduced. It is compared with the usual Bloch and Born—von Karman boundary condition which is shown to be a Hückel condition in the sense of LCAO MO treatment of a ring structure. The potential relevance of this Möbius condition to one-dimensional molecular and liquid crystals in which the relative molecular orientation changes during phase transition is alluded to. A comparison of the energies for the twisted and non-twisted form of the linear crystal is derived in the LCAO approximation. The orbital symmetry correlation in the concerted twist of the atomic or molecular orbitals atom! the linear backbone during a rotational polymorphic structural transition is also derived.
Electron-correlation-induced band renormalization and Mott transition in Ca1-xSrxVO3
Institute of Scientific and Technical Information of China (English)
Wang Guang-Tao; Zhang Min-Ping; Zheng Li-Hua
2011-01-01
We present the local density approximate+Gutzwiller results for the electronic structure of Ca1-xSryVO3. The substitution of Sr 2+ by Ca2+ reduces the bandwidth,as the V-O-V bond angle decreases from 180°for SrVO3 to about 160°for CaVO3. However,we find that the bandwidth decrease induced by the V-O-V bond angle decrease is smaller as compared to that induced by electron correlation. In correlated electron systems,such as Ca1-xSr. V03,the correlation effect of 3d electrons plays a leading role in determining the bandwidth. The electron correlation effect and crystal field splitting collaboratively determine whether the compounds will be in a metal state or in a Mottinsulator phase.
2016-02-17
Strong Electron Hybridization and Fermi-to-Non-Fermi Liquid Transition in LaCu, Chemistry of Materials, (01 2015): 211. doi: 10.1021/cm503781s...Robert Paria Sena, Joke Hadermann, Gabriel Kotliar, Martha Greenblatt. Hole Doping and Structural Transformation in CsTl, Inorganic Chemistry , (02...PbMn(IV)TeO6: A New Noncentrosymmetric Layered Honeycomb Magnetic Oxide, Inorganic Chemistry , (02 2016): 1333. doi: 10.1021/acs.inorgchem.5b02677
75 FR 67751 - Medicare Program: Community-Based Care Transitions Program (CCTP) Meeting
2010-11-03
... provide a forum for community-based organizations, hospitals, Quality Improvement Organizations... materials will be posted on the CMS Care Transitions Web site prior to the meeting. FOR FURTHER INFORMATION CONTACT: Juliana Tiongson, Social Science Research Analyst, Centers for Medicare & Medicaid Services,...
GIS-based Approaches to Catchment Area Analyses of Mass Transit
DEFF Research Database (Denmark)
Andersen, Jonas Lohmann Elkjær; Landex, Alex
2009-01-01
Catchment area analyses of stops or stations are used to investigate potential number of travelers to public transportation. These analyses are considered a strong decision tool in the planning process of mass transit especially railroads. Catchment area analyses are GIS-based buffer and overlay...
Holiday Destination Choice Behavior Analysis Based on AFC Data of Urban Rail Transit
Directory of Open Access Journals (Sweden)
Chang-jun Cai
2015-01-01
Full Text Available For urban rail transit, the spatial distribution of passenger flow in holiday usually differs from weekdays. Holiday destination choice behavior analysis is the key to analyze passengers’ destination choice preference and then obtain the OD (origin-destination distribution of passenger flow. This paper aims to propose a holiday destination choice model based on AFC (automatic fare collection data of urban rail transit system, which is highly expected to provide theoretic support to holiday travel demand analysis for urban rail transit. First, based on Guangzhou Metro AFC data collected on New Year’s day, the characteristics of holiday destination choice behavior for urban rail transit passengers is analyzed. Second, holiday destination choice models based on MNL (Multinomial Logit structure are established for each New Year’s days respectively, which takes into account some novel explanatory variables (such as attractiveness of destination. Then, the proposed models are calibrated with AFC data from Guangzhou Metro using WESML (weighted exogenous sample maximum likelihood estimation and compared with the base models in which attractiveness of destination is not considered. The results show that the ρ2 values are improved by 0.060, 0.045, and 0.040 for January 1, January 2, and January 3, respectively, with the consideration of destination attractiveness.
Csank, Jeffrey T.; Stueber, Thomas J.
2012-01-01
An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10- by 10-Foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.
Superconductivity on the verge of electronic topological transition in Fe based superconductors
Ghosh, Haranath; Sen, Smritijit
2017-04-01
A comprehensive first principles study on the electronic topological transition in a number of 122 family of Fe based superconductors is presented. Doping as well as temperature driven Lifshitz transitions are predicted from ab-initio simulations in a variety of Fe based superconductors that are consistent with experimental findings. In all the studied compounds the Lifshitz transitions are consistently found to take place at a doping concentration just around where superconductivity is known to acquire the highest Tc and magnetism disappears. This indicates the intriguing heed to the inter-relationship between superconductivity and Lifshitz transition in Fe-based 122 materials. Systematically, the Lifshitz transition occurs (above certain threshold doping) in some of the electronic Fermi surfaces for hole doped 122 compounds, whereas in hole Fermi surfaces for electron as well as iso-electronic doped 122 compounds. Temperature driven Lifshitz transition is found to occur in the iso-electronic Ru-doped BaFe2As2 compounds. A systematic study of Fermi surface area e.g., variations of (i) areas of each individual Fermi surfaces, (ii) sum total areas of all the electron Fermi Surfaces, (iii) sum total areas of all the hole Fermi Surfaces, (iv) sum total areas of all the five Fermi Surfaces, (v) difference of all hole and all electron Fermi surface areas as a function of doping is a rare wealth of information that can be verified by the de Haas-van Alphen and allied effects (i.e. , Shubnikov-de Haas effect) are presented. Fermi surface area are found to carry sensitivity of topological modifications more acutely than the band structures and can be used as a better experimental tool to identify ETT/LT.
Simoni, Daniele; Lengani, Davide; Guida, Roberto
2016-09-01
The transition process of the boundary layer growing over a flat plate with pressure gradient simulating the suction side of a low-pressure turbine blade and elevated free-stream turbulence intensity level has been analyzed by means of PIV and hot-wire measurements. A detailed view of the instantaneous flow field in the wall-normal plane highlights the physics characterizing the complex process leading to the formation of large-scale coherent structures during breaking down of the ordered motion of the flow, thus generating randomized oscillations (i.e., turbulent spots). This analysis gives the basis for the development of a new procedure aimed at determining the intermittency function describing (statistically) the transition process. To this end, a wavelet-based method has been employed for the identification of the large-scale structures created during the transition process. Successively, a probability density function of these events has been defined so that an intermittency function is deduced. This latter strictly corresponds to the intermittency function of the transitional flow computed trough a classic procedure based on hot-wire data. The agreement between the two procedures in the intermittency shape and spot production rate proves the capability of the method in providing the statistical representation of the transition process. The main advantages of the procedure here proposed concern with its applicability to PIV data; it does not require a threshold level to discriminate first- and/or second-order time-derivative of hot-wire time traces (that makes the method not influenced by the operator); and it provides a clear evidence of the connection between the flow physics and the statistical representation of transition based on theory of turbulent spot propagation.
Intrusion detection method based on nonlinear correlation measure
Ambusaidi, Mohammed A.; Tan, Zhiyuan; He, Xiangjian; Nanda, Priyadarsi; Lu, Liang Fu; Jamdagni, Aruna
2014-01-01
Cyber crimes and malicious network activities have posed serious threats to the entire internet and its users. This issue is becoming more critical, as network-based services, are more widespread and closely related to our daily life. Thus, it has raised a serious concern in individual internet user
Design and implementation of photon correlator based on C8051F
Shen, Jin; Li, Yuming; Liu, Wei; Yang, Yan; Cheng, Yanting
2008-02-01
Correlation techniques are widely used to extract spectral information from light scattering and other stochastic processes. Within the photon correlation system, the correlating operation must work at a high speed. In this paper, a photon correlator based on microcontroller C8051F was developed. In the photon correlator, the work of counting and scratch is completed by the two 4-bits binary adder 74F161, which is connected to form an 8-bits adder., and the correlation operation of every channel is carried out by the software of C8051F. By probably choosing high speed devices counting of 10ns in width pulses can be counted. The correlation operations including multiplying and addition operation of 56 channels with the circulation program within 3μs were made in interrupt service routine of the C8051F. The work in this paper can be applied in the ultra-fine particle sizing with photon correlation spectroscopy.
Noise-Induced Transitions in a Population Growth Model Based on Size-Dependent Carrying Capacity
Directory of Open Access Journals (Sweden)
Neeme Lumi
2014-01-01
Full Text Available The stochastic dynamics of a population growth model with size-dependent carrying capacity is considered. The effect of a fluctuating environment on population growth is modeled as a multiplicative dichotomous noise. At intermediate values of population size the deterministic counterpart of the model behaves similarly to the Von Foerster model for human population, but at small and very large values of population size substantial differences occur. In the stochastic case, an exact analytical solution for the stationary probability distribution is found. It is established that variation of noise correlation time can cause noise-induced transitions between three different states of the system characterized by qualitatively different behaviors of the probability distributions of the population size. Also, it is shown that, in some regions of the system parameters, variation of the amplitude of environmental fluctuations can induce single unidirectional abrupt transitions of the mean population size.
A Semi-Continuous State-Transition Probability HMM-Based Voice Activity Detector
Directory of Open Access Journals (Sweden)
H. Othman
2007-02-01
Full Text Available We introduce an efficient hidden Markov model-based voice activity detection (VAD algorithm with time-variant state-transition probabilities in the underlying Markov chain. The transition probabilities vary in an exponential charge/discharge scheme and are softly merged with state conditional likelihood into a final VAD decision. Working in the domain of ITU-T G.729 parameters, with no additional cost for feature extraction, the proposed algorithm significantly outperforms G.729 Annex B VAD while providing a balanced tradeoff between clipping and false detection errors. The performance compares very favorably with the adaptive multirate VAD, option 2 (AMR2.
A Semi-Continuous State-Transition Probability HMM-Based Voice Activity Detector
Directory of Open Access Journals (Sweden)
Othman H
2007-01-01
Full Text Available We introduce an efficient hidden Markov model-based voice activity detection (VAD algorithm with time-variant state-transition probabilities in the underlying Markov chain. The transition probabilities vary in an exponential charge/discharge scheme and are softly merged with state conditional likelihood into a final VAD decision. Working in the domain of ITU-T G.729 parameters, with no additional cost for feature extraction, the proposed algorithm significantly outperforms G.729 Annex B VAD while providing a balanced tradeoff between clipping and false detection errors. The performance compares very favorably with the adaptive multirate VAD, option 2 (AMR2.
Duality-based calculations for transition probabilities in stochastic chemical reactions
Ohkubo, Jun
2017-02-01
An idea for evaluating transition probabilities in chemical reaction systems is proposed, which is efficient for repeated calculations with various rate constants. The idea is based on duality relations; instead of direct time evolutions of the original reaction system, the dual process is dealt with. Usually, if one changes rate constants of the original reaction system, the direct time evolutions should be performed again, using the new rate constants. On the other hands, only one solution of an extended dual process can be reused to calculate the transition probabilities for various rate constant cases. The idea is demonstrated in a parameter estimation problem for the Lotka-Volterra system.
Transition-based deadlock control policy using reachability graph for flexible manufacturing systems
Directory of Open Access Journals (Sweden)
Xiuyan Zhang
2016-02-01
Full Text Available Most existing deadlock prevention policies deal with deadlock problems arising in flexible manufacturing systems modeled with Petri nets by adding control places. Based on the reachability graph analysis, this article proposes a novel deadlock control policy that recovers the system from deadlock and livelock states to legal states and reaches the same number of states as the original plant model by adding control transitions. In order to reduce the structural complexity of the supervisor, a set covering approach is developed to minimize the number of control transitions. Finally, two flexible manufacturing system examples are presented to illustrate the proposed approach.
Correlation between magnetoencephalography-based "clusterectomy" and postoperative seizure freedom.
Vadera, Sumeet; Jehi, Lara; Burgess, Richard C; Shea, Katherine; Alexopoulos, Andreas V; Mosher, John; Gonzalez-Martinez, Jorge; Bingaman, William
2013-06-01
During the presurgical evaluation of patients with medically intractable focal epilepsy, a variety of noninvasive studies are performed to localize the hypothetical epileptogenic zone and guide the resection. Magnetoencephalography (MEG) is becoming increasingly used in the clinical realm for this purpose. No investigators have previously reported on coregisteration of MEG clusters with postoperative resection cavities to evaluate whether complete "clusterectomy" (resection of the area associated with MEG clusters) was performed or to compare these findings with postoperative seizure-free outcomes. The authors retrospectively reviewed the charts and imaging studies of 65 patients undergoing MEG followed by resective epilepsy surgery from 2009 until 2012 at the Cleveland Clinic. Preoperative MEG studies were fused with postoperative MRI studies to evaluate whether clusters were within the resected area. These data were then correlated with postoperative seizure freedom. Sixty-five patients were included in this study. The average duration of follow-up was 13.9 months, the mean age at surgery was 23.1 years, and the mean duration of epilepsy was 13.7 years. In 30 patients, the main cluster was located completely within the resection cavity, in 28 it was completely outside the resection cavity, and in 7 it was partially within the resection cavity. Seventy-four percent of patients were seizure free at 12 months after surgery, and this rate decreased to 60% at 24 months. Improved likelihood of seizure freedom was seen with complete clusterectomy in patients with localization outside the temporal lobe (extra-temporal lobe epilepsy) (p = 0.04). In patients with preoperative MEG studies that show clusters in surgically accessible areas outside the temporal lobe, we suggest aggressive resection to improve the chances for seizure freedom. When the cluster is found within the temporal lobe, further diagnostic testing may be required to better localize the epileptogenic zone.
An Eavesdropping Detecting Approach Based on Mode-Mode Correlation
Institute of Scientific and Technical Information of China (English)
XIONG Jin; ZENG Gui-Hua; ZHOU Nan-Run
2005-01-01
@@ We find that second-order coherence as well as a Hanbury-Brown-Twiss intensity interferometer may provide an optimal approach for eavesdropping detection in the quantum key distribution based on two-mode squeezed'vacuum states. With this approach, eavesdropping can be easily detected without sacrificing extra secret bits as the test key. In addition, the efficiency of the quantum key distribution protocol is enhanced greatly.
The Transition to Marked-Based Monetary Policy: What Can China Learn from the European Experience?
Oxelheim, Lars; Forssbæck , Jens
2007-01-01
We discuss the prospects for Chinese money market development and transition to market-based monetary policy operations based on a comparative historical analysis of the present Chinese situation and the development in 11 European countries from 1979 up to the launch of European Economic and Monetary Union (EMU). Central banks in the latter group typically had an incentive to encourage the formation of efficient benchmark segments in the domestic money markets for the conduct of open market o...
Structure Dependence of Lysosomal Transit of Chitosan-Based Polyplexes for Gene Delivery.
Thibault, Marc; Lavertu, Marc; Astolfi, Mélina; Buschmann, Michael D
2016-10-01
Chitosan-based polyplexes are known to traffic through lysosomes for a relatively long time, independent of the degree of deacetylation (DDA) and the number average molecular weight (Mn) of the polymer, even though both of these parameters have profound effects on polyplex stability and transfection efficiency. A better understanding of the lysosomal barrier is paramount to the rational design of vectors capable of overcoming obstacles to transgene expression. The aim of the present study was to investigate if lysosomal transit affects chitosan-based polyplex transfection efficiency in a structure-dependent (DDA, Mn) manner. Toward this end, we analyzed the effects of intracellular trafficking modifying agents on transfection efficiency and intracellular vesicular trafficking of polyplexes with different structural properties and stabilities or nucleic acid binding affinity. The use of agents that modify endosome/lysosome acidification and transit processes by distinct mechanisms and their effect on cell viability, polyplex uptake, vesicular trafficking, and transfection efficiency revealed novel and strong chitosan structure-dependent consequences of lysosomal transit. Inhibiting lysosomal transit using chloroquine significantly increased the efficiency of unstable polyplexes, while having minimal effects for polyplexes with intermediate or high stability. In parallel, specifically inhibiting the acidification of vesicles abrogated transfection for all formulations, suggesting that vesicular acidification is essential to promote transfection, most probably by facilitating lysosomal escape. These results provide novel insights into the structure-performance relationship of chitosan-based gene delivery systems.
Phase Transition Analysis Based Quality Prediction for Multi-phase Batch Processes
Institute of Scientific and Technical Information of China (English)
赵露平; 赵春晖; 高福荣
2012-01-01
Batch processes are usually involved with multiple phases in the time domain and many researches on process monitoring as well as quality prediction have been done using phase information. However, few of them consider phase transitions, though they exit widely in batch processes and have non-ignorable impacts on product qualities. In the present work, a phase-based partial least squares (PLS) method utilizing transition information is proposed to give both online and offline quality predictions. First, batch processes are divided into several phases using regression parameters other than prior process knowledge. Then both steady phases and transitions which have great influences on qualities are identified as critical-to-quality phases using statistical methods. Finally, based on the analysis of different characteristics of transitions and steady phases, an integrated algorithm is developed for quality prediction. The application to an injection molding process shows the effectiveness of the proposed algorithm in comparison with the traditional MPLS method and the phase-based PLS method.
TRUFAS, a wavelet based algorithm for the rapid detection of planetary transits
Regulo, C; Alonso, R; Deeg, H J; Cortes, T Roca
2007-01-01
Aims: We describe a fast, robust and automatic detection algorithm, TRUFAS, and apply it to data that are being expected from the CoRoT mission. Methods: The procedure proposed for the detection of planetary transits in light curves works in two steps: 1) a continuous wavelet transformation of the detrended light curve with posterior selection of the optimum scale for transit detection, and 2) a period search in that selected wavelet transformation. The detrending of the light curves are based on Fourier filtering or a discrete wavelet transformation. TRUFAS requires the presence of at least 3 transit events in the data. Results: The proposed algorithm is shown to identify reliably and quickly the transits that had been included in a standard set of 999 light curves that simulate CoRoT data. Variations in the pre-processing of the light curves and in the selection of the scale of the wavelet transform have only little effect on TRUFAS' results. Conclusions: TRUFAS is a robust and quick transit detection algor...
Coe, J P; Paterson, M J
2014-01-01
We calculate potential curves for transition metal dimers using Monte Carlo configuration interaction (MCCI). These results, and their associated spectroscopic values, are compared with experimental and computational studies. The multireference nature of the MCCI wavefunction is quantified and we estimate the important orbitals. We initially consider the ground state of the chromium dimer. Next we calculate potential curves for Sc$_{2}$ where we contrast the lowest triplet and quintet states. We look at the molybdenum dimer where we compare non-relativistic results with the partial inclusion of relativistic effects via effective core potentials, and report results for scandium nickel.
Kim, J. H.; Oh, Sangjun; Xu, X.; Joo, Jinho; Rindflesich, M.; Tomsic, M; Dou, S. X.
2009-01-01
The change in the lattice parameters or the lattice disorder is claimed as a cause of the slight reduction in the transition temperature by carbon doping in MgB2. In this work, an extensive investigation on the effects of carbohydrate doping has been carried out. It is found that not only the a-axis but also the c-axis lattice parameter increases with the sintering temperature. A linear relation between the unit cell volume and the critical temperature is observed. Compared with the well know...
Trends in Correlation-Based Pattern Recognition and Tracking in Forward-Looking Infrared Imagery
Alam, Mohammad S.; Bhuiyan, Sharif M. A.
2014-01-01
In this paper, we review the recent trends and advancements on correlation-based pattern recognition and tracking in forward-looking infrared (FLIR) imagery. In particular, we discuss matched filter-based correlation techniques for target detection and tracking which are widely used for various real time applications. We analyze and present test results involving recently reported matched filters such as the maximum average correlation height (MACH) filter and its variants, and distance classifier correlation filter (DCCF) and its variants. Test results are presented for both single/multiple target detection and tracking using various real-life FLIR image sequences. PMID:25061840
Eigenvoice-based MAP adaptation within correlation subspace
Institute of Scientific and Technical Information of China (English)
LUO Jun; OU Zhi-jian; WANG Zuo-ying
2006-01-01
In recent years,the eigenvoice approach has proven to be an efficient method for rapid speaker adaptation,which directs the adaptation according to the analysis of full speaker vector space.In this article,we developed a new algorithm for eigenspace-based adaptation restricting eigenvoices in clustered subspaces, and maximum likelihood (ML) criterion was replaced with maximum aposteriori (MAP) criterion for better parameter estimation.Experiments show that even with one sentence adaptation data this algorithm would result in 6.45 % error ratio reduction relatively,which overcomes the instability of maximum likelihood linear regression (MLLR) with limited data and is much faster than traditional MAP method.This algorithm is not highly-dependent on subspace number of division,thus it proved to be a robust adaptation algorithm.
Molecular-Based Optical Measurement Techniques for Transition and Turbulence in High-Speed Flow
Bathel, Brett F.; Danehy, Paul M.; Cutler, Andrew D.
2013-01-01
High-speed laminar-to-turbulent transition and turbulence affect the control of flight vehicles, the heat transfer rate to a flight vehicle's surface, the material selected to protect such vehicles from high heating loads, the ultimate weight of a flight vehicle due to the presence of thermal protection systems, the efficiency of fuel-air mixing processes in high-speed combustion applications, etc. Gaining a fundamental understanding of the physical mechanisms involved in the transition process will lead to the development of predictive capabilities that can identify transition location and its impact on parameters like surface heating. Currently, there is no general theory that can completely describe the transition-to-turbulence process. However, transition research has led to the identification of the predominant pathways by which this process occurs. For a truly physics-based model of transition to be developed, the individual stages in the paths leading to the onset of fully turbulent flow must be well understood. This requires that each pathway be computationally modeled and experimentally characterized and validated. This may also lead to the discovery of new physical pathways. This document is intended to describe molecular based measurement techniques that have been developed, addressing the needs of the high-speed transition-to-turbulence and high-speed turbulence research fields. In particular, we focus on techniques that have either been used to study high speed transition and turbulence or techniques that show promise for studying these flows. This review is not exhaustive. In addition to the probe-based techniques described in the previous paragraph, several other classes of measurement techniques that are, or could be, used to study high speed transition and turbulence are excluded from this manuscript. For example, surface measurement techniques such as pressure and temperature paint, phosphor thermography, skin friction measurements and
GROUND-BASED TRANSIT OBSERVATIONS OF THE SUPER-EARTH 55 Cnc e
Energy Technology Data Exchange (ETDEWEB)
De Mooij, E. J. W. [Astronomy and Astrophysics, University of Toronto, Toronto (Canada); López-Morales, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States); Karjalainen, R.; Hrudkova, M. [Isaac Newton Group of Telescopes, La Palma (Spain); Jayawardhana, Ray, E-mail: demooij@astro.utoronto.ca [Physics and Astronomy, York University, Toronto (Canada)
2014-12-20
We report the first ground-based detections of the shallow transit of the super-Earth exoplanet 55 Cnc e using a 2 m class telescope. Using differential spectrophotometry, we observed one transit in 2013 and another in 2014, with average spectral resolutions of ∼700 and ∼250, spanning the Johnson BVR photometric bands. We find a white light planet-to-star radius ratio of 0.0190{sub −0.0027}{sup +0.0023} from the 2013 observations and 0.0200{sub −0.0018}{sup +0.0017} from the 2014 observations. The two data sets combined result in a radius ratio of 0.0198{sub −0.0014}{sup +0.0013}. These values are all in agreement with previous space-based results. Scintillation noise in the data prevents us from placing strong constraints on the presence of an extended hydrogen-rich atmosphere. Nevertheless, our detections of 55 Cnc e in transit demonstrate that moderate-sized telescopes on the ground will be capable of routine follow-up observations of super-Earth candidates discovered by the Transiting Exoplanet Survey Satellite around bright stars. We expect it also will be possible to place constraints on the atmospheric characteristics of those planets by devising observational strategies to minimize scintillation noise.
Ground-Based Transit Observations of the Super-Earth 55 Cnc e
de Mooij, E J W; Karjalainen, R; Hrudkova, M; Jayawardhana, R
2014-01-01
We report the first ground-based detections of the shallow transit of the super-Earth exoplanet 55 Cnc e using a 2-meter-class telescope. Using differential spectrophotometry, we observed one transit in 2013 and another in 2014, with average spectral resolutions of ~700 and ~250, spanning the Johnson BVR photometric bands. We find a white-light planet-to-star radius ratio of 0.0190 -0.0027+0.0023 from the 2013 observations and 0.0200 -0.0018+0.0017 from the 2014 observations. The two datasets combined results in a radius ratio of 0.0198 -0.0014+0.0013. These values are all in agreement with previous space-based results. Scintillation noise in the data prevents us from placing strong constraints on the presence of an extended hydrogen-rich atmosphere. Nevertheless, our detections of 55 Cnc e in transit demonstrate that moderate-size telescopes on the ground will be capable of routine follow-up observations of super-Earth candidates discovered by the Transiting Exoplanet Survey Satellite (TESS) around bright st...
Modeling of metamagnetism in metallic-based materials with first-order transitions
Energy Technology Data Exchange (ETDEWEB)
Yi Jin, E-mail: yijin@gwmail.gwu.edu [Institute for Magnetics Research, George Washington University, Washington DC 20052 (United States); Gu Shuo; Della Torre, Edward; Bennett, Lawrence H. [Institute for Magnetics Research, George Washington University, Washington DC 20052 (United States); Provenzano, Virgil [Metallurgy Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
2012-05-01
During the past decade, the magnetic properties of metallic-based materials with first-order transitions have been extensively studied, motivated in part by the observation of large magnetocaloric effect (MCE) peaks displayed by these materials near room temperature. These large peaks are believed to be the result of the materials' magnetic properties at the metamagnetic region, characterized by (i) the thermal-induced transition from the ferromagnetic state (FM) to the paramagnetic state (PM) near the Curie temperature (T{sub C}) and (ii) the field-induced transition from PM state to FM state above T{sub C}. We developed a phenomenological model that utilizes the materials' mixed-state probability function to model the materials' complex hysteretic and properties at metamagnetic region. The approximate probability functions are obtained from the first and second derivatives of the magnetization curve. The probability functions are used to separate the materials' magnetization into a FM state component and a PM state component. The applicability of the model is demonstrated for a metallic-based metamagnetic material, Gd{sub 5}Si{sub 2}Ge{sub 2} compound, where the modeled behaviors show remarkable agreement with the experimental data at the metamagnetic region and provide new physical insights in this mixed-state region. Specifically, in the region of metamagnetic transition, the PM state component is non-reversible and is a function of the FM state component.
Kim, HyunJin; Choi, Kang-Il
2016-01-01
This paper proposes a pipelined non-deterministic finite automaton (NFA)-based string matching scheme using field programmable gate array (FPGA) implementation. The characteristics of the NFA such as shared common prefixes and no failure transitions are considered in the proposed scheme. In the implementation of the automaton-based string matching using an FPGA, each state transition is implemented with a look-up table (LUT) for the combinational logic circuit between registers. In addition, multiple state transitions between stages can be performed in a pipelined fashion. In this paper, it is proposed that multiple one-to-one state transitions, called merged state transitions, can be performed with an LUT. By cutting down the number of used LUTs for implementing state transitions, the hardware overhead of combinational logic circuits is greatly reduced in the proposed pipelined NFA-based string matching scheme.
Energy Technology Data Exchange (ETDEWEB)
Tang, Min; Yang, Xian-feng; Yang, Shang-wen; Han, Peng; Ma, Yi-ming; Yu, Hui; Zhu, Bin, E-mail: zhubinradio@163.com
2014-09-15
Purpose: To investigate the prevalence of lumbosacral transitional vertebra (LSTV) within the Chinese Han population, and to determine whether LSTV correlates with low back pain (LBP) and gluteal pain. Materials and methods: Typical standing pelvic radiographs were obtained for 5860 volunteers between 18 to 60 years of age. The lumbosacral region of each spine was evaluated to identify LSTV, which was classified into types I, II, III, and IV based on Castellvi's method. Histories of low back symptoms were obtained using a questionnaire. The association of different subtypes of LSTV with LBP and gluteal pain was explored. Results: LSTV was found in 15.8% (928 of 5860) of our study population. Of the 928 individuals with LSTV, 44.8% were type I (dysplastic transverse process with height >19 mm), 43.2% were type II (pseudoarticulation), 7.2% were type III (fusion), and 4.8% were type IV (a unilateral type II transition with a type III fusion on the contralateral side). Type II LSTV were closely associated with LBP and gluteal pain, with respective odds ratios (ORs) of 2.56 (95% CI: 2.17–3.89) and 5.38 (95% CI: 4.29–8.43). Similarly, types IV LSTV also demonstrated a significant correlation with LBP and gluteal pain, with respective ORs of 4.28 (95% CI: 3.21–6.35) and 6.82 (95% CI: 5.17–16.59). Conclusions: In this population-based study, the prevalence of LSTV was 15.8%, with type I being the most common. Importantly, LSTV types II and IV were significantly associated with LBP and gluteal pain.
Tang, Min; Yang, Xian-feng; Yang, Shang-wen; Han, Peng; Ma, Yi-ming; Yu, Hui; Zhu, Bin
2014-09-01
To investigate the prevalence of lumbosacral transitional vertebra (LSTV) within the Chinese Han population, and to determine whether LSTV correlates with low back pain (LBP) and gluteal pain. Typical standing pelvic radiographs were obtained for 5860 volunteers between 18 to 60 years of age. The lumbosacral region of each spine was evaluated to identify LSTV, which was classified into types I, II, III, and IV based on Castellvi's method. Histories of low back symptoms were obtained using a questionnaire. The association of different subtypes of LSTV with LBP and gluteal pain was explored. LSTV was found in 15.8% (928 of 5860) of our study population. Of the 928 individuals with LSTV, 44.8% were type I (dysplastic transverse process with height >19mm), 43.2% were type II (pseudoarticulation), 7.2% were type III (fusion), and 4.8% were type IV (a unilateral type II transition with a type III fusion on the contralateral side). Type II LSTV were closely associated with LBP and gluteal pain, with respective odds ratios (ORs) of 2.56 (95% CI: 2.17-3.89) and 5.38 (95% CI: 4.29-8.43). Similarly, types IV LSTV also demonstrated a significant correlation with LBP and gluteal pain, with respective ORs of 4.28 (95% CI: 3.21-6.35) and 6.82 (95% CI: 5.17-16.59). In this population-based study, the prevalence of LSTV was 15.8%, with type I being the most common. Importantly, LSTV types II and IV were significantly associated with LBP and gluteal pain. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Bowring, S. A.; Grotzinger, J. P.; Amthor, J.; Martin, M. E.
2001-05-01
The precise, global correlation of Precambrian and Paleozoic sedimentary rocks can be achieved using temporally calibrated chemostratigraphic records. This approach is essential for determining rates and causes of environmental and faunal change, including mass extinctions. For example, The Neoproterozoic is marked by major environmental change, including periods of global glaciation, large fluctuations in the sequestration of carbon and major tectonic reorganization followed by the explosive diversification of animals in the earliest Cambrian. The extreme climatic change associated with these glaciations have been implicated as a possible trigger for the Cambrian explosion. The recognition of thin zircon-bearing air-fall ash in Neoproterozoic and Cambrian rocks has allowed the establishment of a high-precision temporal framework for animal evolution and is helping to untangle the history of glaciations. In some cases analytical uncertainties translate to age uncertainties of less than 1 Ma and when integrated with chemostratigraphy, the potential for global correlations at even higher resolution. Progress in the global correlation of Neoproterozoic strata has been achieved through the use of C and Sr isotope chemostratigraphy although it has been hampered by a lack of precise geochronological and faunal control. For example, the period from ca 800-580 Ma is characterized by at least two and perhaps as many as four glacial events that are interpreted by many to be global glaciations on a "Snowball Earth". A lack of precise chronological constraints on the number and duration of glaciations, multiple large excursions in the carbon isotopic record, and an absence of detailed biostratigraphy have complicated global correlation and hindered our understanding of this important period of Earth history. However, the ongoing integration of chemostratigraphic and geochronological data are improving temporal resolution and detailed correlations. These data are critical for
Philip, A. K.; Pathak, Kamla
2008-01-01
A dry process induced phase transited, non disintegrating, controlled release, in situ formed asymmetric membrane capsular system for poorly water soluble drug, ketoprofen, was developed and evaluated both in vitro and in vivo for osmotic and controlled release of the drug. In situ formed asymmetric membrane capsules were prepared using fabricated glass capsule holders via dry, phase inversion process. Effect of varying osmotic pressure of the dissolution medium on drug release was studied. Membrane characterization by scanning electron microscopy showed an outer dense region with less pores and an inner porous region for the prepared asymmetric membrane. In vitro release studies and statistical test for all the prepared and marketed formulation were done at P >0.05. The drug release was found to be independent of the pH, but dependent on the osmotic pressure of the dissolution medium. In vivo pharmacokinetic studies showed a level A correlation (R2>0.99) with 39.24 % relative bioavailability compared to immediate release tablet of ketoprofen. Excellent correlation achieved suggested that the in vivo performance of the phase transited in situ formed AMCs could be accurately predicted from their in vitro release profiles and could a means for controlled delivery of drugs with varying solubility. PMID:21369435
Directory of Open Access Journals (Sweden)
Sean S Downey
Full Text Available Analysis of the proportion of immature skeletons recovered from European prehistoric cemeteries has shown that the transition to agriculture after 9000 BP triggered a long-term increase in human fertility. Here we compare the largest analysis of European cemeteries to date with an independent line of evidence, the summed calibrated date probability distribution of radiocarbon dates (SCDPD from archaeological sites. Our cemetery reanalysis confirms increased growth rates after the introduction of agriculture; the radiocarbon analysis also shows this pattern, and a significant correlation between both lines of evidence confirms the demographic validity of SCDPDs. We analyze the areal extent of Neolithic enclosures and demographic data from ethnographically known farming and foraging societies and we estimate differences in population levels at individual sites. We find little effect on the overall shape and precision of the SCDPD and we observe a small increase in the correlation with the cemetery trends. The SCDPD analysis supports the hypothesis that the transition to agriculture dramatically increased demographic growth, but it was followed within centuries by a general pattern of collapse even after accounting for higher settlement densities during the Neolithic. The study supports the unique contribution of SCDPDs as a valid demographic proxy for the demographic patterns associated with early agriculture.
Directory of Open Access Journals (Sweden)
Philip A
2008-01-01
Full Text Available A dry process induced phase transited, non disintegrating, controlled release, in situ formed asymmetric membrane capsular system for poorly water soluble drug, ketoprofen, was developed and evaluated both in vitro and in vivo for osmotic and controlled release of the drug. In situ formed asymmetric membrane capsules were prepared using fabricated glass capsule holders via dry, phase inversion process. Effect of varying osmotic pressure of the dissolution medium on drug release was studied. Membrane characterization by scanning electron microscopy showed an outer dense region with less pores and an inner porous region for the prepared asymmetric membrane. In vitro release studies and statistical test for all the prepared and marketed formulation were done at P > 0.05. The drug release was found to be independent of the pH, but dependent on the osmotic pressure of the dissolution medium. In vivo pharmacokinetic studies showed a level A correlation (R 2> 0.99 with 39.24 % relative bioavailability compared to immediate release tablet of ketoprofen. Excellent correlation achieved suggested that the in vivo performance of the phase transited in situ formed AMCs could be accurately predicted from their in vitro release profiles and could a means for controlled delivery of drugs with varying solubility.
Correlated Edge Overlaps in Multiplex Networks
Baxter, Gareth J; da Costa, Rui A; Dorogovtsev, Sergey N; Mendes, José F F
2016-01-01
We develop the theory of sparse multiplex networks with partially overlapping links based on their local tree-likeness. This theory enables us to find the giant mutually connected component in a two-layer multiplex network with arbitrary correlations between connections of different types. We find that correlations between the overlapping and non-overlapping links markedly change the phase diagram of the system, leading to multiple hybrid phase transitions. For assortative correlations we observe recurrent hybrid phase transitions.
Ochi, Masayuki; Arita, Ryotaro; Tsuneyuki, Shinji
2017-01-13
Obtaining accurate band structures of correlated solids has been one of the most important and challenging problems in first-principles electronic structure calculation. There have been promising recent active developments of wave function theory for condensed matter, but its application to band-structure calculation remains computationally expensive. In this Letter, we report the first application of the biorthogonal transcorrelated (BITC) method: self-consistent, free from adjustable parameters, and systematically improvable many-body wave function theory, to solid-state calculations with d electrons: wurtzite ZnO. We find that the BITC band structure better reproduces the experimental values of the gaps between the bands with different characters than several other conventional methods. This study paves the way for reliable first-principles calculations of the properties of strongly correlated materials.
Ochi, Masayuki; Arita, Ryotaro; Tsuneyuki, Shinji
2017-01-01
Obtaining accurate band structures of correlated solids has been one of the most important and challenging problems in first-principles electronic structure calculation. There have been promising recent active developments of wave function theory for condensed matter, but its application to band-structure calculation remains computationally expensive. In this Letter, we report the first application of the biorthogonal transcorrelated (BITC) method: self-consistent, free from adjustable parameters, and systematically improvable many-body wave function theory, to solid-state calculations with d electrons: wurtzite ZnO. We find that the BITC band structure better reproduces the experimental values of the gaps between the bands with different characters than several other conventional methods. This study paves the way for reliable first-principles calculations of the properties of strongly correlated materials.
Directory of Open Access Journals (Sweden)
Ledesma-Soto Yadira
2012-03-01
Full Text Available Abstract Background Prolactin is secreted from the pituitary gland and other organs, as well as by cells such as lymphocytes. Prolactin has an immunostimulatory effect and is associated with autoimmune diseases that are characterised by abnormal B cell activation, such as systemic lupus erythematosus (SLE. Our aim was to determine if different splenic B cell subsets express the prolactin receptor and if the presence of prolactin influences these B cell subsets and correlates with development of lupus. Results Using real-time PCR and flow cytometry, we found that different subsets of immature (transitional and mature (follicular, marginal zone B cells express different levels of the prolactin receptor and are differentially affected by hyperprolactinaemia. We found that transitional B cells express the prolactin receptor at higher levels compared to mature B cells in C57BL/6 mice and the lupus-prone MRL/lpr and MRL mouse strains. Transitional-1 (T1 B cells showed a higher level of prolactin receptor expression in both MRL/lpr and MRL mice compared to C57BL/6 mice. Hyperprolactinaemia was induced using metoclopramide, which resulted in the development of early symptoms of SLE. We found that T1 B cells are the main targets of prolactin and that prolactin augments the absolute number of T1 B cells, which reflects the finding that this B cell subpopulation expresses the highest level of the prolactin receptor. Conclusions We found that all B cell subsets express the prolactin receptor but that transitional B cells showed the highest prolactin receptor expression levels. Hyperprolactinaemia in mice susceptible to lupus accelerated the disease and increased the absolute numbers of T1 and T3 B cells but not of mature B cells, suggesting a primary effect of prolactin on the early stages of B cell maturation in the spleen and a role of prolactin in B cell differentiation, contributing to SLE onset.
Tunable 0–π transition by interband coupling in iron-based superconductor Josephson junctions
Tao, Y. C.; Liu, S. Y.; Bu, N.; Wang, J.; Di, Y. S.
2016-01-01
An extended four-component Bogoliubov–de Gennes equation is applied to study the Josephson effect in ballistic limit between either two iron-based superconductors (SCs) or an iron-based SC and a conventional s-wave SC, separated by a normal metal. A 0–π transition as a function of interband coupling strength α is always exhibited, arising from the tuning of mixing between the two trajectories with opposite phases. The novel property can be experimentally used to discriminate the {s}+/- -wave pairing symmetry in the iron-based SCs from the {s}++-wave one in MgB2. The effect of interface transparency on the 0–π transition is also presented. The 0–π transition as a function of α is wholly distinct from that as a function of barrier strength or temperature in recent theories (Linder et al 2009 Phys. Rev. B 80 020503(R)). The possible experimental probe of the phase-shift effect in iron-based SC Josephson junctions is commented on as well.
A GPU-based Real-time Software Correlation System for the Murchison Widefield Array Prototype
Wayth, Randall B.; Greenhill, Lincoln J.; Briggs, Frank H.
2009-08-01
Modern graphics processing units (GPUs) are inexpensive commodity hardware that offer Tflop/s theoretical computing capacity. GPUs are well suited to many compute-intensive tasks including digital signal processing. We describe the implementation and performance of a GPU-based digital correlator for radio astronomy. The correlator is implemented using the NVIDIA CUDA development environment. We evaluate three design options on two generations of NVIDIA hardware. The different designs utilize the internal registers, shared memory, and multiprocessors in different ways. We find that optimal performance is achieved with the design that minimizes global memory reads on recent generations of hardware. The GPU-based correlator outperforms a single-threaded CPU equivalent by a factor of 60 for a 32-antenna array, and runs on commodity PC hardware. The extra compute capability provided by the GPU maximizes the correlation capability of a PC while retaining the fast development time associated with using standard hardware, networking, and programming languages. In this way, a GPU-based correlation system represents a middle ground in design space between high performance, custom-built hardware, and pure CPU-based software correlation. The correlator was deployed at the Murchison Widefield Array 32-antenna prototype system where it ran in real time for extended periods. We briefly describe the data capture, streaming, and correlation system for the prototype array.
Magnetic Lifshitz transition and its consequences in multi-band iron-based superconductors
Ptok, Andrzej; Kapcia, Konrad J.; Cichy, Agnieszka; Oleś, Andrzej M.; Piekarz, Przemysław
2017-01-01
In this paper we address Lifshitz transition induced by applied external magnetic field in a case of iron-based superconductors, in which a difference between the Fermi level and the edges of the bands is relatively small. We introduce and investigate a two-band model with intra-band pairing in the relevant parameters regime to address a generic behaviour of a system with hole-like and electron-like bands in external magnetic field. Our results show that two Lifshitz transitions can develop in analysed systems and the first one occurs in the superconducting phase and takes place at approximately constant magnetic field. The chosen sets of the model parameters can describe characteristic band structure of iron-based superconductors and thus the obtained results can explain the experimental observations in FeSe and Co-doped BaFe2As2 compounds. PMID:28165043
Ground-based multisite observations of two transits of HD 80606b
Shporer, A; Dreizler, S; Colon, K D; Wood-Vasey, W M; Choi, P I; Morley, C; Moutou, C; Welsh, W F; Pollaco, D; Starkey, D; Adams, E; Barros, S C C; Bouchy, F; Cabrera-Lavers, A; Cerutti, S; Coban, L; Costello, K; Deeg, H; Diaz, R F; Esquerdo, G A; Fernandez, J; Fleming, S W; Ford, E B; Fulton, B J; Good, M; Hebrard, G; Holman, M J; Hunt, M; Kadakia, S; Lander, G; Lockhart, M; Mazeh, T; Morehead, R C; Nelson, B E; Nortmann, L; Reyes, F; Roebuck, E; Rudy, A R; Ruth, R; Simpson, E; Vincent, C; Weaver, G; Xie, J -W
2010-01-01
We present ground-based optical observations of the September 2009 and January 2010 transits of HD 80606b. Based on 3 partial light curves of the September 2009 event, we derive a midtransit time of T_c [HJD] = 2455099.196 +- 0.026, which is about 1 sigma away from the previously predicted time. We observed the January 2010 event from 9 different locations, with most phases of the transit being observed by at least 3 different teams. We determine a midtransit time of T_c [HJD] = 2455210.6502 +- 0.0064, which is within 1.3 sigma of the time derived from a Spitzer observation of the same event.
Efficient Algorithm for Asymptotics-Based CI and Electronic Structure of Transition Metal Atoms
Mendl, Christian
2010-01-01
Asymptotics-based CI methods are a class of Configuration-Interaction (CI) methods for atoms which reproduce, at fixed finite subspace dimension, the exact Schr\\"odinger eigenstates in the limit of fixed electron number and large nuclear charge. Here we develop, implement, and apply to 3d transition metal atoms an efficient and accurate algorithm for asymptotics-based CI. Efficiency gains come from exact (symbolic) decomposition of the CI space into irreducible symmetry subspaces at essentially linear computational cost, use of reduced density matrices in order to avoid having to store wavefunctions, and use of Slater-type orbitals (STO's). The required Coulomb integrals for STO's are evaluated in closed form, with the help of Hankel matrices, Fourier analysis, and residue calculus. Applications to 3d transition metal atoms are in good agreement with experimental data. In particular we reproduce the anomalous magnetic moment and orbital filling of Chromium in the otherwise regular series Ca, Sc, Ti, V, Cr.
Martiniano, Rui; Cassidy, Lara M; Ó'Maoldúin, Ros; McLaughlin, Russell; Silva, Nuno M; Manco, Licinio; Fidalgo, Daniel; Pereira, Tania; Coelho, Maria J; Serra, Miguel; Burger, Joachim; Parreira, Rui; Moran, Elena; Valera, Antonio C; Porfirio, Eduardo; Boaventura, Rui; Silva, Ana M; Bradley, Daniel G
2017-07-01
We analyse new genomic data (0.05-2.95x) from 14 ancient individuals from Portugal distributed from the Middle Neolithic (4200-3500 BC) to the Middle Bronze Age (1740-1430 BC) and impute genomewide diploid genotypes in these together with published ancient Eurasians. While discontinuity is evident in the transition to agriculture across the region, sensitive haplotype-based analyses suggest a significant degree of local hunter-gatherer contribution to later Iberian Neolithic populations. A more subtle genetic influx is also apparent in the Bronze Age, detectable from analyses including haplotype sharing with both ancient and modern genomes, D-statistics and Y-chromosome lineages. However, the limited nature of this introgression contrasts with the major Steppe migration turnovers within third Millennium northern Europe and echoes the survival of non-Indo-European language in Iberia. Changes in genomic estimates of individual height across Europe are also associated with these major cultural transitions, and ancestral components continue to correlate with modern differences in stature.
Hou, Futao; Yuan, Weijie; Huang, Jin; Qian, Liyuan; Chen, Zhikang; Ge, Jie; Wu, Shaobin; Chen, Jinxiang; Wang, Jixu; Chen, Zihua
2012-12-01
The expression of EphA2 and three epithelial-mesenchymal transition-related proteins (E-cadherin, β-catenin and vimentin) was detected by immunohistochemistry in human gastric cancer and normal gastric mucosa. The expression of EphA2 and vimentin was significantly higher in gastric cancer tissues than in normal gastric mucosa tissues, and similar results were found for negative E-cadherin expression and ectopic β-catenin expression. Further analysis showed that the expression of EphA2 was closely correlated with the depth of tumor invasion, tumor-node-metastasis (TNM) stages and lymph node metastasis. Down-regulated expression of the epithelial protein E-cadherin, overexpression of the mesenchymal protein vimentin and ectopic expression of β-catenin were associated with the depth of tumor invasion, tumor differentiation, TNM stages and lymph node metastasis. The Spearman rank test indicated that the positive expression of EphA2 was negatively associated with E-cadherin expression and was positively correlated with β-catenin ectopic expression and vimentin expression. In addition, the Kaplan-Meier survival analysis showed that the overexpression of EphA2 and vimentin, ectopic expression of β-catenin and down-regulation of E-cadherin indicate a poor outcome. Moreover, multivariate Cox analysis showed that TNM stages, lymph node metastasis, EphA2 expression, E-cadherin expression and β-catenin ectopic expression were independent prognostic factors for postoperative gastric cancer. These findings indicate that the overexpression of EphA2 correlates with the loss of epithelial proteins and the appearance of mesenchymal proteins. Therefore, EphA2 may play a role in epithelial-mesenchymal transition in gastric cancer.
THE CONSTRUCTIONS OF ALMOST BINARY SEQUENCE PAIRS WITH THREE-LEVEL CORRELATION BASED ON CYCLOTOMY
Institute of Scientific and Technical Information of China (English)
Peng Xiuping; Xu Chengqian
2012-01-01
In this paper,a new class of almost binary sequence pair with a single zero element is presented.The almost binary sequence pairs with three-level correlation are constructed based on cyclotomic numbers of order 2,4,and 6.Most of them have good correlation and balance property,whose maximum nontrivial correlation magnitudes are 2 and the difference between the numbers of occurrence of +1's and -1's are 0 or 1.In addition,the corresponding binary sequence pairs are investigated as well and we can also get some kinds of binary sequence pairs with optimum balance and good correlation.
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
In order to elucidate the mechanisms of multidrug resistance (MDR) in bladder cancer, the expression of glutathione S-transferase-π (GST-π) and multidrug resistance associated protein (MRP) in tissue samples resected from 44 patients and 6 normal bladder mucosa as control was detected by using immunohistochemica[ method, and the results were analyzed by computer-assisted image analyzing system (IAS) to achieve semi-quantitative data. In addition, correlation between the expression of both factors was studied. The results showed that the positive expression rate of GSTπ and MRP in bladder cancer was 72. 7 % (32/44) and 68. 2 0% (30/44) respectively, significantly higher than those in normal bladder mucosa, being 16.7 %0 and 33.3 % respectively. The rate of GST-π positive staining was increased correspondingly with tumor grade and stage elevated, being higher in recurrent tumors treated by chemotherapy, but not significantly (P＞0. 05). There was no significant differences between the expression of MRP and tumors' behaviors and clinical characters. However, the results demonstrated that the correlation between the expression of both resistant fac tors was very evident (r=0. 695, P＜0. 0025). It was suggested that the activation of GST-π and MRP might occur during malignant transformation of normal mucosa, but tumors' differentiation and progression could not be the unique factors that influenced both overexpression. Chemotherapy might be another important reason. The correlation of both indicated that there was a common mechanism regulating their expression probably, which made them play a pivotal role in chemotherapy drug resistance of bladder cancers.
Luman Wang; Qiaochu Mo; Jianxin Wang
2015-01-01
Most current gene coexpression databases support the analysis for linear correlation of gene pairs, but not nonlinear correlation of them, which hinders precisely evaluating the gene-gene coexpression strengths. Here, we report a new database, MIrExpress, which takes advantage of the information theory, as well as the Pearson linear correlation method, to measure the linear correlation, nonlinear correlation, and their hybrid of cell-specific gene coexpressions in immune cells. For a given ge...
Correlation of self-assessment with attendance in an evidence-based medicine course
National Research Council Canada - National Science Library
Ramirez, Beatriz U
2015-01-01
.... Therefore, it appeared interesting to evaluate if a stronger correlation between attendance and grades would occur in a face-to-face "evidence-based medicine" course with few lectures and more time...
Current-biased Transition-edge Sensors Based on Re-entrant Superconductors
Gulian, A.; Nikoghosyan, V.; Tollaksen, J.; Vardanyan, V.; Kuzanyan, A.
Transition-edge sensors are widely recognized as one of the most sensitive tools for the photon and particles detection in many areas, from astrophysics to quantum computing. Their application became practical after understanding that rather than being biased in a constant current mode, they should be biased in a constant voltage mode. Despite the methods of voltage biasing of these sensors are well developed since then, generally the current biasing is more convenient for superconducting circuits. Thus transition-edge sensors designed inherently to operate in the current-biased mode are desirable. We developed a design for such detectors based on re-entrant superconductivity. In this case constant current biasing takes place in the normal state, below the superconducting transition, so that following the absorption of a photon it does not yield a latching. Rather, the sensor gains energy and shifts towards the lower resistant (e.g., superconducting) state, and then cools down faster (since Joule heating is now reduced), and resets in a natural way to be able to detect the next photon. We prototyped this kind of transition edge sensors and tested them operational in accordance with the outlined physics. The samples used in experiments were modified compositions of YBCO-superconductors in a ceramic form (which, as we discovered, reproducibly demonstrates re-entrant superconductivity). In this presentation we report their composition, methods of preparation, and the detection results. This approach, in some areas, may have practical advantage over the traditional voltage-biased devices.
High-accuracy optical clock based on the octupole transition in 171Yb+
Huntemann, N; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E
2011-01-01
We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition 2S1/2(F=0) -> F7/2(F=3) in a single trapped 171Yb+ ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric quadrupole moment of the 2F7/2 state is measured as -0.041(5) e(a0)^2, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe light induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1x10^(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz with the uncertainty essentially determined by the employed caesium fountain reference.
High-accuracy optical clock based on the octupole transition in 171Yb+.
Huntemann, N; Okhapkin, M; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E
2012-03-02
We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition (2)S(1/2)(F=0)→(2)F(7/2)(F=3) in a single trapped (171)Yb(+) ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f(13)6s(2) configuration of the upper state. The electric-quadrupole moment of the (2)F(7/2) state is measured as -0.041(5)ea(0)(2), where e is the elementary charge and a(0) the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz.
Frequency standard based on the octupole transition in {sup 171}Yb{sup +}
Energy Technology Data Exchange (ETDEWEB)
Huntemann, Nils; Okhapkin, Maxim; Lipphard, Burghard; Weyers, Stefan; Tamm, Christian; Peik, Ekkehard [Fachbereich Zeit und Frequenz, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)
2011-07-01
W present our results on the development of a new optical frequency standard based on the electric octupole (E3) transition {sup 2}S{sub 1/2}(F=0) {yields} {sup 2}F{sub 7/2}(F=3) of a single trapped laser-cooled {sup 171}Yb{sup +} ion at 467 nm. In comparison with a previously realized optical frequency standard in {sup 171}Yb{sup +} this E3 transition benefits from smaller systematic level shifts due to external fields and its negligible natural linewidth. Another important aspect of the new standard is its strong dependence on variations of the fine structure constant {alpha}. A recently built probe laser system and the use of a new efficient repump scheme allows to observe Fourier transform-limited linewidths below 7 Hz and a resonant excitation probability of more than 90 %. We lock the probe laser frequency to the resonance signal of the E3 transition and use a real-time extrapolation scheme to eliminate the huge light shift induced by the probe field. The unperturbed transition frequency was measured by a comparison to a caesium fountain clock using a frequency comb generator. The resulting uncertainty was mainly limited by the systematic uncertainty of the fountain clock.
Multiple phase transitions in an agent-based evolutionary model with neutral fitness.
King, Dawn M; Scott, Adam D; Bahar, Sonya
2017-04-01
Null models are crucial for understanding evolutionary processes such as speciation and adaptive radiation. We analyse an agent-based null model, considering a case without selection-neutral evolution-in which organisms are defined only by phenotype. Universal dynamics has previously been demonstrated in a related model on a neutral fitness landscape, showing that this system belongs to the directed percolation (DP) universality class. The traditional null condition of neutral fitness (where fitness is defined as the number of offspring each organism produces) is extended here to include equal probability of death among organisms. We identify two types of phase transition: (i) a non-equilibrium DP transition through generational time (i.e. survival), and (ii) an equilibrium ordinary percolation transition through the phenotype space (based on links between mating organisms). Owing to the dynamical rules of the DP reaction-diffusion process, organisms can only sparsely fill the phenotype space, resulting in significant phenotypic diversity within a cluster of mating organisms. This highlights the necessity of understanding hierarchical evolutionary relationships, rather than merely developing taxonomies based on phenotypic similarity, in order to develop models that can explain phylogenetic patterns found in the fossil record or to make hypotheses for the incomplete fossil record of deep time.
Shock Position Control for Mode Transition in a Turbine Based Combined Cycle Engine Inlet Model
Csank, Jeffrey T.; Stueber, Thomas J.
2013-01-01
A dual flow-path inlet for a turbine based combined cycle (TBCC) propulsion system is to be tested in order to evaluate methodologies for performing a controlled inlet mode transition. Prior to experimental testing, simulation models are used to test, debug, and validate potential control algorithms which are designed to maintain shock position during inlet disturbances. One simulation package being used for testing is the High Mach Transient Engine Cycle Code simulation, known as HiTECC. This paper discusses the development of a mode transition schedule for the HiTECC simulation that is analogous to the development of inlet performance maps. Inlet performance maps, derived through experimental means, describe the performance and operability of the inlet as the splitter closes, switching power production from the turbine engine to the Dual Mode Scram Jet. With knowledge of the operability and performance tradeoffs, a closed loop system can be designed to optimize the performance of the inlet. This paper demonstrates the design of the closed loop control system and benefit with the implementation of a Proportional-Integral controller, an H-Infinity based controller, and a disturbance observer based controller; all of which avoid inlet unstart during a mode transition with a simulated disturbance that would lead to inlet unstart without closed loop control.
Using frame correlation algorithm in a duration distribution based hidden Markov model
Institute of Scientific and Technical Information of China (English)
王作英; 崔小东
2000-01-01
The assumption of frame independence is a widely known weakness of traditional hidden Markov model (HMM). In this paper, a frame correlation algorithm based on the duration distribution based hidden Markov model (DDBHMM) is proposed. In the algorithm, an AR model is used to depict the low pass effect of vocal tract from which stems the inertia leading to frame correlation. In the preliminary experiment of middle vocabulary speaker dependent isolated word recognition, our frame correlation algorithm outperforms the frame independent one. The average error reduction is about 20% .
Performance of Narrowband Signal Detection under Correlated Rayleigh Fading Based on Synthetic Array
Directory of Open Access Journals (Sweden)
Ali Broumandan
2009-01-01
design parameters of probability of detection (Pd and probability of false alarm (Pfa. An optimum detector based on Estimator-Correlator (EC is developed, and its performance is compared with that of suboptimal Equal-Gain (EG combiner in different channel correlation scenarios. It is shown that in moderate channel correlation scenarios the detection performance of EC and EG is identical. The sensitivity of the proposed method to knowledge of motion parameters is also investigated. An extensive set of measurements based on CDMA-2000 pilot signals using the static antenna and synthetic array are used to experimentally verify these theoretical findings.
Oyedepo, Gbenga A; Wilson, Angela K
2010-08-26
The correlation consistent Composite Approach, ccCA [ Deyonker , N. J. ; Cundari , T. R. ; Wilson , A. K. J. Chem. Phys. 2006 , 124 , 114104 ] has been demonstrated to predict accurate thermochemical properties of chemical species that can be described by a single configurational reference state, and at reduced computational cost, as compared with ab initio methods such as CCSD(T) used in combination with large basis sets. We have developed three variants of a multireference equivalent of this successful theoretical model. The method, called the multireference correlation consistent composite approach (MR-ccCA), is designed to predict the thermochemical properties of reactive intermediates, excited state species, and transition states to within chemical accuracy (e.g., 1 kcal/mol for enthalpies of formation) of reliable experimental values. In this study, we have demonstrated the utility of MR-ccCA: (1) in the determination of the adiabatic singlet-triplet energy separations and enthalpies of formation for the ground states for a set of diradicals and unsaturated compounds, and (2) in the prediction of energetic barriers to internal rotation, in ethylene and its heavier congener, disilene. Additionally, we have utilized MR-ccCA to predict the enthalpies of formation of the low-lying excited states of all the species considered. MR-ccCA is shown to give quantitative results without reliance upon empirically derived parameters, making it suitable for application to study novel chemical systems with significant nondynamical correlation effects.
Energy Technology Data Exchange (ETDEWEB)
Kuebler, C.
2007-07-30
Phase-matched optical rectification together with standard EOS methods gives direct access to the real-time evolution of the electric field of ultrashort THz pulses. This opens up a new field of experiments, in which the complex dielectric function or equivalently the frequency-dependent conductivity of solid state systems is monitored resonantly throughout the MIR and FIR with a femtosecond temporal resolution. Optical rectification of amplified laser pulses allows for the generation of electric fields of several 10 kV cm-1 up to 1 MV cm-1, depending on the laser pulse energy. Such highly energetic field transients may be employed to coherently drive low-energy transitions into the nonlinear regime. The problems which are inherent to standard EOS, i.e. a fixed detector response and a limited bandwidth, are absent in phase-matched EOS. If this novel detection technique is combined with phase-matched optical rectification, an extremely versatile multi-THz spectrometer is obtained. The accessible frequency range is extended toward the near infrared. In addition, both the emission spectrum and the detector response may be custom tailored to fit specific spectroscopic requirements. Proper choice of the phasematching geometry eliminates multiple time delayed reflections of the main THz pulse, resulting in an essentially unlimited frequency resolution. In the context of optical pump - multi-THz probe experiments the implementation of a photoelastic modulator results in significant improvement of the signal-to-noise ratio: Balancing of the differential detector is rendered less critical and the measurement time in a 2D time-resolved experiment is reduced by up to two orders of magnitude. Finally, the combination of phase-matched optical rectification and phasematched electro-optic sampling shows great scaling potential with respect to both achieving higher field energies and shorter wavelengths. (orig.)
Riedel, Michael; Collett, Timothy S.
2017-01-01
A global inventory of data from gas hydrate drilling expeditions is used to develop relationships between the base of structure I gas hydrate stability, top of gas hydrate occurrence, sulfate-methane transition depth, pressure (water depth), and geothermal gradients. The motivation of this study is to provide first-order estimates of the top of gas hydrate occurrence and associated thickness of the gas hydrate occurrence zone for climate-change scenarios, global carbon budget analyses, or gas hydrate resource assessments. Results from publically available drilling campaigns (21 expeditions and 52 drill sites) off Cascadia, Blake Ridge, India, Korea, South China Sea, Japan, Chile, Peru, Costa Rica, Gulf of Mexico, and Borneo reveal a first-order linear relationship between the depth to the top and base of gas hydrate occurrence. The reason for these nearly linear relationships is believed to be the strong pressure and temperature dependence of methane solubility in the absence of large difference in thermal gradients between the various sites assessed. In addition, a statistically robust relationship was defined between the thickness of the gas hydrate occurrence zone and the base of gas hydrate stability (in meters below seafloor). The relationship developed is able to predict the depth of the top of gas hydrate occurrence zone using observed depths of the base of gas hydrate stability within less than 50 m at most locations examined in this study. No clear correlation of the depth to the top and base of gas hydrate occurrences with geothermal gradient and sulfate-methane transition depth was identified.
Research on micro-blog based personal interests and emotion transition tendency
Directory of Open Access Journals (Sweden)
Jiushuo WANG
2015-04-01
Full Text Available With the rapid development of social network, people can present or share their opinions and emotions on the micro-blog, and as a result, large amount of blog texts and emotional information of different topics are produced. As the traditional text mining algorithms cannot deal with these blog texts with fractional contents and different personal emotions effectively, this paper presents a novel weighting computation approach based on the key characters of micro-blog posts to get the dynamic interests of bloggers on different times. Furthermore, based on the emotion classification, the emotion transition tendency analysis can also be implemented. Experimental results show the feasibility of the presented approach.
Chohan, Zahid H.; Munawar, Asifa; Supuran, Claudiu T
2001-01-01
Some novel transition metal [Co(II), Cu(II), Ni(II) and Zn(II)] complexes of substituted pyridine Schiff-bases have been prepared and characterized by physical, spectral and analytical data. The synthesized Schiff-bases act as deprotonated tridentate for the complexation reaction with Co(II), Ni(II) and Zn(II) ions. The new compounds, possessing the general formula [M(L)2] where [M=Co(II), Cu(II), Ni(II) and Zn(II) and HL=HL1, HL2, HL3 and HL4] show an octahedral geometry. In order to evaluat...
GaN based transfer electron and avalanche transit time devices
Institute of Scientific and Technical Information of China (English)
R.K.Parida; A.K.Panda
2012-01-01
A new model is developed to study the microwave/mm wave characteristics of two-terminal GaN- based transfer electron devices (TEDs),namely a Gunn diode and an impact avalanche transit time (IMPATT) device.Microwave characteristics such as device efficiency and the microwave power generated are computed and compared at D-band (140 GHz center frequency) to see the potentiality of each device under the same operating conditions.It is seen that GaN-based IMPATT devices surpass the Gunn diode in the said frequency region.
GaN based transfer electron and avalanche transit time devices
Parida, R. K.; Panda, A. K.
2012-05-01
A new model is developed to study the microwave/mm wave characteristics of two-terminal GaN-based transfer electron devices (TEDs), namely a Gunn diode and an impact avalanche transit time (IMPATT) device. Microwave characteristics such as device efficiency and the microwave power generated are computed and compared at D-band (140 GHz center frequency) to see the potentiality of each device under the same operating conditions. It is seen that GaN-based IMPATT devices surpass the Gunn diode in the said frequency region.
Graphene-based transition metal oxide nanocomposites for the oxygen reduction reaction
Sun, Meng; Liu, Huijuan; Liu, Yang; Qu, Jiuhui; Li, Jinghong
2015-01-01
The development of low cost, durable and efficient nanocatalysts to substitute expensive and rare noble metals (e.g. Pt, Au and Pd) in overcoming the sluggish kinetic process of the oxygen reduction reaction (ORR) is essential to satisfy the demand for sustainable energy conversion and storage in the future. Graphene based transition metal oxide nanocomposites have extensively been proven to be a type of promising highly efficient and economic nanocatalyst for optimizing the ORR to solve the world-wide energy crisis. Synthesized nanocomposites exhibit synergetic advantages and avoid the respective disadvantages. In this feature article, we concentrate on the recent leading works of different categories of introduced transition metal oxides on graphene: from the commonly-used classes (FeOx, MnOx, and CoOx) to some rare and heat-studied issues (TiOx, NiCoOx and Co-MnOx). Moreover, the morphologies of the supported oxides on graphene with various dimensional nanostructures, such as one dimensional nanocrystals, two dimensional nanosheets/nanoplates and some special multidimensional frameworks are further reviewed. The strategies used to synthesize and characterize these well-designed nanocomposites and their superior properties for the ORR compared to the traditional catalysts are carefully summarized. This work aims to highlight the meaning of the multiphase establishment of graphene-based transition metal oxide nanocomposites and its structural-dependent ORR performance and mechanisms.
Navigating the transition to ecosystem-based management of the Great Barrier Reef, Australia.
Olsson, Per; Folke, Carl; Hughes, Terry P
2008-07-15
We analyze the strategies and actions that enable transitions toward ecosystem-based management using the recent governance changes of the Great Barrier Reef Marine Park as a case study. The interplay among individual actors, organizations, and institutions at multiple levels is central in such transitions. A flexible organization, the Great Barrier Reef Marine Park Authority, was crucial in initiating the transition to ecosystem-based management. This agency was also instrumental in the subsequent transformation of the governance regime and provided leadership throughout the process. Strategies involved internal reorganization and management innovation, leading to an ability to coordinate the scientific community, to increase public awareness of environmental issues and problems, to involve a broader set of stakeholders, and to maneuver the political system for support at critical times. The transformation process was induced by increased pressure on the Great Barrier Reef (from terrestrial runoff, overharvesting, and global warming) that triggered a new sense of urgency to address these challenges. The focus of governance shifted from protection of selected individual reefs to stewardship of the larger-scale seascape. The study emphasizes the significance of stewardship that can change patterns of interactions among key actors and allow for new forms of management and governance to emerge in response to environmental change. This example illustrates that enabling legislations or other social bounds are essential, but not sufficient for shifting governance toward adaptive comanagement of complex marine ecosystems.
Jamhawi, Abdelqader; Paul, Anam C.; Smith, Justin D.; Handa, Sachin; Liu, Jinjun
2017-06-01
Transition-metal complexes of rare earth metals including ruthenium and iridium are most commonly employed as visible-light photocatalysts. Despite their highly important and broad applications, they have many disadvantages including high cost associated with low abundance in earth crust, potential toxicity, requirement of specialized ligands for desired activity, and difficulty in recycling of metal contents as well as associated ligands. Polymer-based organophotoredox catalysts are promising alternatives and possess unique advantages such as easier synthesis from inexpensive starting material, longer excited state life time, broad range of activity, sustainability, and recyclability. In this research talk, time-resolved photoluminescence and femtosecond transient absorption (TA) spectroscopy measurements of three novel polymer-based organophotoredox catalysts will be presented. By our synthetic team, their catalytic activity has been proven in some highly valuable chemical transformations, that otherwise require transition metal complexes. Time-resolved spectroscopic investigations have demonstrated that photoinduced processes in these catalysts are similar to the transition metal complexes. Especially, intramolecular vibrational relaxation, internal conversion, and intersystem crossing from the S1 state to the T1 state all occur on a sub-picosecond timescale. The long lifetime of the T1 state ( 2-3 microsecond) renders these polymers potent oxidizing and reducing agents. A spectroscopic and kinetic model has been developed for global fitting of TA spectra in both the frequency and time domains. Implication of the current ultrafast spectroscopy studies of these novel molecules to their roles in photocatalysis will be discussed.
Silicene and transition metal based materials: prediction of a two-dimensional piezomagnet
Energy Technology Data Exchange (ETDEWEB)
Dzade, Nelson Y; Obodo, Kingsley O; Adjokatse, Sampson K; Ashu, Akosa C; Amankwah, Emmanuel; Atiso, Clement D; Bello, Abdulhakeem A; Igumbor, Emmanuel; Nzabarinda, Stany B; Obodo, Joshua T; Ogbuu, Anthony O; Femi, Olu Emmanuel; Udeigwe, Josephine O; Waghmare, Umesh V [African University of Science and Technology, Abuja (Nigeria)
2010-09-22
We use first-principles density functional theory based calculations to determine the stability and properties of silicene, a graphene-like structure made from silicon, and explore the possibilities of modifying its structure and properties through incorporation of transition metal ions (M: Ti, Nb, Ta, Cr, Mo and W) in its lattice, forming MSi{sub 2}. While pure silicene is stable in a distorted honeycomb lattice structure obtained by opposite out-of-plane displacements of the two Si sub-lattices, its electronic structure still exhibits linear dispersion with the Dirac conical feature similar to graphene. We show that incorporation of transition metal ions in its lattice results in a rich set of properties with a clear dependence on the structural changes, and that CrSi{sub 2} forms a two-dimensional magnet exhibiting a strong piezomagnetic coupling.
Smart textile-based wearable biomedical systems: a transition plan for research to reality.
Park, Sungmee; Jayaraman, Sundaresan
2010-01-01
The field of smart textile-based wearable biomedical systems (ST-WBSs) has of late been generating a lot of interest in the research and business communities since its early beginnings in the mid-nineties. However, the technology is yet to enter the marketplace and realize its original goal of enhancing the quality of life for individuals through enhanced real-time biomedical monitoring. In this paper, we propose a framework for analyzing the transition of ST-WBS from research to reality. We begin with a look at the evolution of the field and describe the major components of an ST-WBS. We then analyze the key issues encompassing the technical, medical, economic, public policy, and business facets from the viewpoints of various stakeholders in the continuum. We conclude with a plan of action for transitioning ST-WBS from "research to reality."
Computing with dynamical systems based on insulator-metal-transition oscillators
Parihar, Abhinav; Shukla, Nikhil; Jerry, Matthew; Datta, Suman; Raychowdhury, Arijit
2017-04-01
In this paper, we review recent work on novel computing paradigms using coupled oscillatory dynamical systems. We explore systems of relaxation oscillators based on linear state transitioning devices, which switch between two discrete states with hysteresis. By harnessing the dynamics of complex, connected systems, we embrace the philosophy of "let physics do the computing" and demonstrate how complex phase and frequency dynamics of such systems can be controlled, programmed, and observed to solve computationally hard problems. Although our discussion in this paper is limited to insulator-to-metallic state transition devices, the general philosophy of such computing paradigms can be translated to other mediums including optical systems. We present the necessary mathematical treatments necessary to understand the time evolution of these systems and demonstrate through recent experimental results the potential of such computational primitives.
DEFF Research Database (Denmark)
Hopkins, Tom S.; Bailly, Denis; Elmgren, Ragnar
2012-01-01
This article explores the value of the Systems Approach Framework (SAF) as a tool for the transition to sustainable development in coastal zone systems, based on 18 study sites in Europe, where the SAF was developed and tested. The knowledge gained from these experiments concerns the practical......-dependent and system-independent problems, and the inclusion of non-market evaluations. It also develops a real partnership among research, management, and stakeholders to establish a quantitative basis for collaborative decision making. Furthermore, the article argues that the transition to sustainable development...... for coastal systems requires consideration of the scale interdependency from individual to global and recognition of the probable global reorganizational emergence of scale-free networks that could cooperate to maximize the integrated sustainability among them...
Svensson, Fredrik; Engen, Karin; Lundbäck, Thomas; Larhed, Mats; Sköld, Christian
2015-09-28
Transition state and high energy intermediate mimetics have the potential to be very potent enzyme inhibitors. In this study, a model of peptide hydrolysis in the active site of insulin-regulated aminopeptidase (IRAP) was developed using density functional theory calculations and the cluster approach. The 3D structure models of the reaction coordinates were used for virtual screening to obtain new chemical starting points for IRAP inhibitors. This mechanism-based virtual screening process managed to identify several known peptidase inhibitors from a library of over 5 million compounds, and biological testing identified one compound not previously reported as an IRAP inhibitor. This novel methodology for virtual screening is a promising approach to identify new inhibitors mimicking key transition states or intermediates of an enzymatic reaction.
Fabrication of superconducting transition edge sensor based on Mo and Au bilayers
Energy Technology Data Exchange (ETDEWEB)
Yun, Minhee [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)]. E-mail: yunmh@engr.pitt.edu; Bock, James [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Keynon, Mattew [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kuo, C.-L. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Leduc, Henry [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Turner, Anthony [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kim, Moon J. [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75083-0688 (United States)
2006-04-15
We report fabricated antenna-coupled superconducting transition edge sensor (TES) for millimeter-wave polarimetry. Superconducting microwave components for an antenna-coupled focal plane will be described in this work. We use low-loss Nb/SiO/Nb transmission line as base materials as a start, although changes in the dielectric may be possible to reduce loss further. Additionally, we have fabricated single- and double-element antennas, filters and detectors. We use TES bilayers consisting of Mo/Au thin films and Nb electrical contacts on a low-stress Si{sub 3}N{sub 4} membrane. In this work, we report transition temperature as a function of Mo thicknesses and Au film composition.
Safety Evaluation of Highway Tunnel-Entrance Illuminance Transition Based on Eye-Pupil Changes
Directory of Open Access Journals (Sweden)
Zhigang Du
2014-10-01
Full Text Available Utilizing the EMR-8B eye-tracker system, the pupil changes of eight drivers were monitored when they drove through 26 typical highway tunnels. Based on the test results, the driver’s pupil areas and pupil illuminance were found to be in a power function relationship at tunnel entrances. Furthermore, a quantitative relationship between the pupil area and its critical velocity was established, and the ratio of pupil area’s velocity in relation to its critical velocity was used to evaluate the lighting transitions and to establish the ideal curve of pupil illuminance at tunnel entrances. The results demonstrated that the relationship between the pupil illuminance of the tunnel entrance and the driver’s pupil areas conforms to the Stevens law found in experimental psychology; severe pupil illuminance transition within the range of 10 metres of the existing highway tunnel entrances, which results in great visual load, is in urgent need of improvement.
Wang, Fang; Wang, Guozhu; Kang, Lie; Wang, Juan
2011-11-01
This paper presents a novel segmentation method for extracting coronary artery tree from angiogram, which is based on multiscale Gabor filtering and transition region extraction. Firstly the enhanced image is obtained after multiscale Gabor filtering, then the transition region of the enhanced image is extracted using the local complexity algorithm, and the final segmentation threshold is calculated, finally the image segmentation is achieved. To evaluate the performance of the proposed approach, we carried out experiments on various sets of angiographic images, and compared its effects with those of the improved top-hat segmentation method. The experiments indicate that the proposed method outperforms the latter method about better extraction of small vessels, more background elimination, better visualized coronary artery tree and continuity of the vessels.
Web Design Based on Integrated and Supervision Control System in City Rail Transit
Li, Xiaojuan; Xing, Yu; Zheng, Hengchao
This paper presents a method of setting up WEB System to Integrated Supervision Control System for the requirements of city Rail Transit. First, basic platform and software/hardware architecture of WEB System are discussed. Then the function module, data flow and communication mechanisms are described and a design based on technologies of SVG and Ajax is proposed and the WEB video release function and system security are described. This design makes it possible that important information of Integrated Supervision Control System can be browsed and queried in external Web pages. Watching Real-time images of all cameras in internal network of Rail Transit is possible, which is providing remote viewing and management functions for metro managers.
Laminar-Turbulent Transition in Raman Fiber Lasers: A First Passage Statistics Based Analysis
Chattopadhyay, Amit K; Sugavanam, Srikanth; Tarasov, Nikita; Churkin, Dmitry
2016-01-01
Loss of coherence with increasing excitation amplitudes and spatial size modulation is a fundamental problem in designing Raman fiber lasers. While it is known that ramping up laser pump power increases the amplitude of stochastic excitations, such higher energy inputs can also lead to a transition from a linearly stable coherent laminar regime to a non-desirable disordered turbulent state. This report presents a new statistical methodology, based on first passage statistics, that classifies lasing regimes in Raman fiber lasers, thereby leading to a fast and highly accurate identification of a strong instability leading to a laminar-turbulent phase transition through a self-consistently defined order parameter. The results have been consistent across a wide range of pump power values, heralding a breakthrough in the non-invasive analysis of fiber laser dynamics.
Rowe, Dawn A.; Test, David W.
2010-01-01
Enhancing parents' ability to make informed choices is important to successful transition planning for youth with disabilities. This study used a multiple probe design across content areas replicated across participants to examine the effects of a computer-based instructional program on acquisition of parents' knowledge of the transition planning…
Rowe, Dawn A.; Test, David W.
2010-01-01
Enhancing parents' ability to make informed choices is important to successful transition planning for youth with disabilities. This study used a multiple probe design across content areas replicated across participants to examine the effects of a computer-based instructional program on acquisition of parents' knowledge of the transition planning…
Institute of Scientific and Technical Information of China (English)
Qin Liu; Hong Li; Yu Zhang
2016-01-01
Objective:To study the Twist and YB-1 gene expression in cervical cancer and cervical intraepithelial neoplasia tissue as well as its correlation with epithelial-mesenchymal transition. Methods:Normal cervical tissue, cervical intraepithelial neoplasia tissue and cervical cancer tissue were collected for study. ELISA kits were used to detect Twist, YB-1, E-cadherin,β-catenin, N-cadherin and Vimentin contents in cervical tissue, and immunohistochemistry was used to detect Twist and YB-1 expression levels in cervical tissue.Results:Twist and YB-1 contents, cell positive rate and immunohistochemical scores as well as N-cadherin and Vimentin contents in cervical cancer tissue and cervical intraepithelial neoplasia tissue were significantly higher than those in normal cervical tissue while E-cadherin andβ-catenin contents were lower than those in normal cervical tissue; Twist and YB-1 contents, cell positive rate and immunohistochemical scores as well as N-cadherin and Vimentin contents in cervical cancer tissue were significantly higher than those in cervical intraepithelial neoplasia tissue while E-cadherin andβ-catenin contents were lower than those in cervical intraepithelial neoplasia tissue; the higher the Twist and YB-1 expression levels in cervical cancer tissue, the lower the E-cadherin andβ-catenin contents, and the higher the N-cadherin and Vimentin contents.Conclusions: Twist and YB-1 gene overexpression can promote epithelial-mesenchymal transition to be involved in the occurrence of cervical cancer and cervical intraepithelial neoplasia.
King, Donna Therese; Ritchie, Stephen M.
2013-05-01
Curriculum developers and researchers have promoted context-based programmes to arrest waning student interest and participation in the enabling sciences at high school and university. Context-based programmes aim for student connections between scientific discourse and real-world contexts to elevate curricular relevance without diminishing conceptual understanding. This interpretive study explored the learning transactions in one 11th grade context-based chemistry classroom where the context was the local creek. The dialectic of agency/structure was used as a lens to examine how the practices in classroom interactions afforded students the agency for learning. The results suggest that first, fluid transitions were evident in the student-student interactions involving successful students; and second, fluid transitions linking concepts to context were evident in the students' successful reports. The study reveals that the structures of writing and collaborating in groups enabled students' agential and fluent movement between the field of the real-world creek and the field of the formal chemistry classroom. Furthermore, characteristics of academically successful students in context-based chemistry are highlighted. Research, teaching, and future directions for context-based science teaching are discussed.
Layering PLGA-based electrospun membranes and cell sheets for engineering cartilage-bone transition.
Mouthuy, P-A; El-Sherbini, Y; Cui, Z; Ye, H
2016-04-01
It is now widely acknowledged that implants that have been designed with an effort towards reconstructing the transition between tissues might improve their functionality and integration in vivo. This paper contributes to the development of improved treatment for articular cartilage repair by exploring the potential of the combination of electrospinning technology and cell sheet engineering to create cartilage tissue. Poly(lactic-co-glycolic acid) (PLGA) was used to create the electrospun membranes. The focus being on the cartilage-bone transition, collagen type I and hydroxyapatite (HA) were also added to the scaffolds to increase the histological biocompatibility. Human mesenchymal stem cells (hMSCs) were cultured in thermoresponsive dishes to allow non-enzymatic removal of an intact cell layer after reaching confluence. The tissue constructs were created by layering electrospun membranes with sheets of hMSCs and were cultured under chondrogenic conditions for up to 21 days. High viability was found to be maintained in the multilayered construct. Under chondrogenic conditions, reverse-transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry have shown high expression levels of collagen type X, a form of collagen typically found in the calcified zone of articular cartilage, suggesting an induction of chondrocyte hypertrophy in the PLGA-based scaffolds. To conclude, this paper suggests that layering electrospun scaffolds and cell sheets is an efficient approach for the engineering of tissue transitions, and in particular the cartilage-bone transition. The use of PLGA-based scaffold might be particularly useful for the bone-cartilage reconstruction, since the differentiated tissue constructs seem to show characteristics of calcified cartilage. Copyright © 2013 John Wiley & Sons, Ltd.
Lea, Toby; Bryant, Joanne; Ellard, Jeanne; Howard, John; Treloar, Carla
2015-03-01
While numerous studies have examined characteristics of young people who have recently initiated injecting, little attention has focused on young people who may be at high risk of transitioning to injecting. This study sought to examine the extent that socially disadvantaged young people were exposed to injecting, determine their level of hepatitis C (HCV) knowledge and identify correlates of higher injecting exposure. A cross-sectional survey was administered to 210 young people in 2010-2011 who were exposed to injecting drug use, but had not transitioned to injecting. Respondents were primarily recruited from youth services in metropolitan Sydney. Exposure to injecting in the previous 12 months was assessed with four items that examined whether close friends, romantic/sexual partners or family members/acquaintances injected drugs, and whether they were offered an injection. Most respondents had at least a few close friends who injected drugs (65%) and almost half had been offered drugs to inject in the previous 12 months (48%). It was less common for respondents to report having a partner who injects (11%). Correlates of higher injecting exposure were examined with multivariate ordinal regression. In the multivariate model, higher exposure to injecting was independently associated with the experience of abuse or violent crime [adjusted odds ratio (AOR) = 1.80] and reporting more favourable attitudes towards injecting (AOR = 0.86). Higher exposure to injecting was not independently associated with patterns or history of drug use. HCV knowledge was low to moderate and was not associated with higher exposure to injecting. That drug use was not independently associated with higher injecting exposure may suggest that exposure is shaped more by social disadvantage than by drug use patterns. Additional research is required to investigate this, using an improved measure of exposure to injecting. © 2014 John Wiley & Sons Ltd.
Indian Academy of Sciences (India)
B Samant; D M Mohabey
2009-11-01
The sedimentary beds associated with Deccan Continental Flood Basalt (DCFB) sequences exposed in the volcanic subprovinces of Jabalpur-Mandla-Chhindwara (JMC) regions of Madhya Pradesh and Nand-Dongargaon (N-D) basin and the adjoining areas to the west in Yeotmal-Nanded in Maharashtra were studied for their palynofloral analysis. The sediments were characterized palynologically and changes in the palynoflora are observed at different stratigraphic levels in a number of sections including several new intertrappean localities recorded in recent years. For the purpose of effective correlation of different subprovinces, palynofloras of some of the previously studied intertrappeans are also reviewed. Our studies suggest that before the start of the Deccan volcanic activity, the palynoflora found in the Lameta sediments, was dominated by gymnosperms-angiosperm association. The plant canopy consisted mainly of gymnosperms (Conifers and Podocarpaceae) whereas, the understory members were mostly of palms and herbs (Poaceae and Asteraceae). The eruption of Deccan volcanic flows severely affected the existing floral association and proved fatal for the well established plant community. The immediately overlying sediments associated with the earliest volcanic flows are dominated by pteridophytes and angiosperm taxa (Azolla cretacea, Aquilapollenites bengalensis, Ariadnaesporites sp., Gabonisporis vigourouxii and Triporoletes reticulatus). Higher up in the stratigraphic sequence, similar forms continued with simultaneous appearance of new taxa including Scabrastephanocolpites spp. At still higher stratigraphic levels, abundance of fungi especially the mycorrhizal fungi, concurrent with sharp decline in pollen/spore recovery was observed. In the culminating phase (i.e. Palaeocene) of Deccan volcanic history a new palynofloral assemblage of typical Palaeocene taxa (Dandotiaspora dilata, D. pseudoauriculata, D. plicata, Spinizonocolpites echinatus, Matanomadhiasulcites sp., and
Wang, Q.; Alfalou, A.; Brosseau, C.
2016-04-01
Here, we report a brief review on the recent developments of correlation algorithms. Several implementation schemes and specific applications proposed in recent years are also given to illustrate powerful applications of these methods. Following a discussion and comparison of the implementation of these schemes, we believe that all-numerical implementation is the most practical choice for application of the correlation method because the advantages of optical processing cannot compensate the technical and/or financial cost needed for an optical implementation platform. We also present a simple iterative algorithm to optimize the training images of composite correlation filters. By making use of three or four iterations, the peak-to-correlation energy (PCE) value of correlation plane can be significantly enhanced. A simulation test using the Pointing Head Pose Image Database (PHPID) illustrates the effectiveness of this statement. Our method can be applied in many composite filters based on linear composition of training images as an optimization means.
Cross-Correlation-Function-Based Multipath Mitigation Method for Sine-BOC Signals
Directory of Open Access Journals (Sweden)
H. H. Chen
2012-06-01
Full Text Available Global Navigation Satellite Systems (GNSS positioning accuracy indoor and urban canyons environments are greatly affected by multipath due to distortions in its autocorrelation function. In this paper, a cross-correlation function between the received sine phased Binary Offset Carrier (sine-BOC modulation signal and the local signal is studied firstly, and a new multipath mitigation method based on cross-correlation function for sine-BOC signal is proposed. This method is implemented to create a cross-correlation function by designing the modulated symbols of the local signal. The theoretical analysis and simulation results indicate that the proposed method exhibits better multipath mitigation performance compared with the traditional Double Delta Correlator (DDC techniques, especially the medium/long delay multipath signals, and it is also convenient and flexible to implement by using only one correlator, which is the case of low-cost mass-market receivers.
Karkut, M. G.; Hake, R. R.
1983-08-01
Superconducting upper critical fields Hc2(T), transition temperatures Tc and normal-state electrical resistivities ρn have been measured in the amorphous transition-metal alloy series Zr1-xCox, Zr1-xNix, (Zr1-xTix)0.78Ni0.22, and (Zr1-xNbx)0.78Ni0.22. Structural integrity of these melt-spun alloys is indicated by x-ray, density, bend-ductility, normal-state electrical resistivity, superconducting transition width, and mixed-state flux-pinning measurements. The specimens display Tc=2.1-3.8 K, ρn=159-190 μΩ cm, and |(dHc2dT)Tc|=28-36 kG/K. These imply electron mean free paths l~2-6 Å, zero-temperature Ginzburg-Landau coherence distances ξG0~50-70 Å, penetration depths λG0~(7-10)×103 Å, and extremely high dirtiness parameters ξ0l~300-1300. All alloys display Hc2(T) curves with negative curvature and (with two exceptions) fair agreement with the standard dirty-limit theory of Werthamer, Helfand, Hohenberg, and Maki (WHHM) for physically reasonable values of spin-orbit-coupling induced, electron-spin-flip scattering time τso. This is in contrast to the anomalously elevated Hc2(T) behavior which is nearly linear in T that is observed by some, and the unphysically low-τso fits to WHHM theory obtained by others, for various amorphous alloys. Current ideas that such anomalies may be due to alloy inhomogeneity are supported by present results on two specimens for which relatively low-τso fits of Hc2(T) to WHHM theory are coupled with superconductive evidence for inhomogeneity: relatively broad transitions at Tc and Hc2 current-density-dependent transitions at Hc2 and (in one specimen) a J-dependent, high-H (>Hc2), resistive "beak effect." In the Zr1-xCox and Zr1-xNix series, Tc decreases linearly with x (and with unfilled-shell average electron-to-atom ratio in the range 5.05previous results for these systems and contrary to the Tc vs behavior of both amorphous and crystalline transition-metal alloys formed between near neighbors in the Periodic Table. Upper
Accurate mask-based spatially regularized correlation filter for visual tracking
Gu, Xiaodong; Xu, Xinping
2017-01-01
Recently, discriminative correlation filter (DCF)-based trackers have achieved extremely successful results in many competitions and benchmarks. These methods utilize a periodic assumption of the training samples to efficiently learn a classifier. However, this assumption will produce unwanted boundary effects, which severely degrade the tracking performance. Correlation filters with limited boundaries and spatially regularized DCFs were proposed to reduce boundary effects. However, their methods used the fixed mask or predesigned weights function, respectively, which was unsuitable for large appearance variation. We propose an accurate mask-based spatially regularized correlation filter for visual tracking. Our augmented objective can reduce the boundary effect even in large appearance variation. In our algorithm, the masking matrix is converted into the regularized function that acts on the correlation filter in frequency domain, which makes the algorithm fast convergence. Our online tracking algorithm performs favorably against state-of-the-art trackers on OTB-2015 Benchmark in terms of efficiency, accuracy, and robustness.
A GPU based real-time software correlation system for the Murchison Widefield Array prototype
Wayth, Randall B; Briggs, Frank H
2009-01-01
Modern graphics processing units (GPUs) are inexpensive commodity hardware that offer Tflop/s theoretical computing capacity. GPUs are well suited to many compute-intensive tasks including digital signal processing. We describe the implementation and performance of a GPU-based digital correlator for radio astronomy. The correlator is implemented using the NVIDIA CUDA development environment. We evaluate three design options on two generations of NVIDIA hardware. The different designs utilize the internal registers, shared memory and multiprocessors in different ways. We find that optimal performance is achieved with the design that minimizes global memory reads on recent generations of hardware. The GPU-based correlator outperforms a single-threaded CPU equivalent by a factor of 60 for a 32 antenna array, and runs on commodity PC hardware. The extra compute capability provided by the GPU maximises the correlation capability of a PC while retaining the fast development time associated with using standard hardw...
Time domain averaging and correlation-based improved spectrum sensing method for cognitive radio
Li, Shenghong; Bi, Guoan
2014-12-01
Based on the combination of time domain averaging and correlation, we propose an effective time domain averaging and correlation-based spectrum sensing (TDA-C-SS) method used in very low signal-to-noise ratio (SNR) environments. With the assumption that the received signals from the primary users are deterministic, the proposed TDA-C-SS method processes the received samples by a time averaging operation to improve the SNR. Correlation operation is then performed with a correlation matrix to determine the existence of the primary signal in the received samples. The TDA-C-SS method does not need any prior information on the received samples and the associated noise power to achieve improved sensing performance. Simulation results are presented to show the effectiveness of the proposed TDA-C-SS method.
Csank, Jeffrey T.; Stueber, Thomas J.
2013-01-01
A dual flow-path inlet system is being tested to evaluate methodologies for a Turbine Based Combined Cycle (TBCC) propulsion system to perform a controlled inlet mode transition. Prior to experimental testing, simulation models are used to test, debug, and validate potential control algorithms. One simulation package being used for testing is the High Mach Transient Engine Cycle Code simulation, known as HiTECC. This paper discusses the closed loop control system, which utilizes a shock location sensor to improve inlet performance and operability. Even though the shock location feedback has a coarse resolution, the feedback allows for a reduction in steady state error and, in some cases, better performance than with previous proposed pressure ratio based methods. This paper demonstrates the design and benefit with the implementation of a proportional-integral controller, an H-Infinity based controller, and a disturbance observer based controller.
Phase-shifting technique applied to circular harmonic-based joint transform correlator
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The phase-shifting technique is applied to the circular harmonic expansion-based joint transform correlator. Computer simulation has shown that the light efficiency and the discrimination capability are greatly enhanced, and the full rotation invariance is preserved after the phase-shifting technique has been used. A rotation-invariant optical pattern recognition with high discrimination capability and high light efficiency is obtained. The influence of the additive noise on the performance of the correlator is also investigated. However, the anti-noise capability of this kind of correlator still needs improving.
Diagnosis of soft faults in analog integrated circuits based on fractional correlation
Institute of Scientific and Technical Information of China (English)
Deng Yong; Shi Yibing; Zhang Wei
2012-01-01
Aiming at the problem of diagnosing soft faults in analog integrated circuits,an approach based on fractional correlation is proposed.First,the Volterra series of the circuit under test (CUT) decomposed by the fractional wavelet packet are used to calculate the fractional correlation functions.Then,the calculated fractional correlation functions are used to form the fault signatures of the CUT.By comparing the fault signatures,the different soft faulty conditions of the CUT are identified and the faults are located.Simulations of benchmark circuits illustrate the proposed method and validate its effectiveness in diagnosing soft faults in analog integrated circuits.
Neural correlates of anxiety in healthy volunteers: a voxel-based morphometry study.
Spampinato, Maria Vittoria; Wood, Jacqueline N; De Simone, Veronica; Grafman, Jordan
2009-01-01
Studies have shown that the amygdala, temporal, and prefrontal cortices play a key role in the expression of anxiety. The correlation between gray matter volume of these structures and behavioral anxiety measures was not previously investigated in healthy volunteers. The authors used voxel-based morphometry to assess the relationship between brain regional volume and anxiety. The authors found an inverse correlation between anxiety measures and cortical volume in regions of the limbic system and prefrontal cortex implicated in the pathogenesis of anxiety disorders. The authors suggest that volumetric variability of these regions may have a correlation with the development of an anxious personality trait.
Deterministic quantum key distribution based on Gaussian-modulated EPR correlations
Institute of Scientific and Technical Information of China (English)
He Guang-Qiang; Zeng Gui-Hua
2006-01-01
This paper proposes a deterministic quantum key distribution scheme based on Gaussian-modulated continuous variable EPR correlations. This scheme can implement fast and efficient key distribution. The security is guaranteed by continuous variable EPR entanglement correlations produced by nondegenerate optical parametric amplifier. For general beam splitter eavesdropping strategy, the secret information rate△I = I(α,β) - I(α,ε) is calculated in view of Shannon information theory. Finally the security analysis is presented.
MaRiMba: a software application for spectral library-based MRM transition list assembly.
Sherwood, Carly A; Eastham, Ashley; Lee, Lik Wee; Peterson, Amelia; Eng, Jimmy K; Shteynberg, David; Mendoza, Luis; Deutsch, Eric W; Risler, Jenni; Tasman, Natalie; Aebersold, Ruedi; Lam, Henry; Martin, Daniel B
2009-10-01
Multiple reaction monitoring mass spectrometry (MRM-MS) is a targeted analysis method that has been increasingly viewed as an avenue to explore proteomes with unprecedented sensitivity and throughput. We have developed a software tool, called MaRiMba, to automate the creation of explicitly defined MRM transition lists required to program triple quadrupole mass spectrometers in such analyses. MaRiMba creates MRM transition lists from downloaded or custom-built spectral libraries, restricts output to specified proteins or peptides, and filters based on precursor peptide and product ion properties. MaRiMba can also create MRM lists containing corresponding transitions for isotopically heavy peptides, for which the precursor and product ions are adjusted according to user specifications. This open-source application is operated through a graphical user interface incorporated into the Trans-Proteomic Pipeline, and it outputs the final MRM list to a text file for upload to MS instruments. To illustrate the use of MaRiMba, we used the tool to design and execute an MRM-MS experiment in which we targeted the proteins of a well-defined and previously published standard mixture.
Directory of Open Access Journals (Sweden)
Zhibin Jiang
2015-04-01
Full Text Available Understanding the nature of rail transit dwell time has potential benefits for both the users and the operators. Crowded passenger trains cause longer dwell times and may prevent some passengers from boarding the first available train that arrives. Actual dwell time and the process of passenger alighting and boarding are interdependent through the sequence of train stops and propagated delays. A comprehensive and feasible dwell time simulation model was developed and optimized to address the problems associated with scheduled timetables. The paper introduces the factors that affect dwell time in urban rail transit systems, including train headway, the process and number of passengers alighting and boarding the train, and the inability of train doors to properly close the first time because of overcrowded vehicles. Finally, based on a time-driven micro-simulation system, Shanghai rail transit Line 8 is used as an example to quantify the feasibility of scheduled dwell times for different stations, directions of travel and time periods, and a proposed dwell time during peak hours in several crowded stations is presented according to the simulation results.
Analysis of Phase Transition in Traffic Flow based on a New Model of Driving Decision
Peng, Yu; Shang, Hua-Yan; Lu, Hua-Pu
2011-07-01
Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton (CA) model, based on the driving decision (DD). In the DD model, a driver's decision is divided into three stages: decision-making, action, and result. The acceleration is taken as a decision variable and three core factors, i.e. distance between adjacent vehicles, their own velocity, and the preceding vehicle's velocity, are considered. Simulation results show that the DD model can simulate the synchronized flow effectively and describe the phase transition in traffic flow well. Further analyses illustrate that various density will cause the phase transition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle's velocity, the deceleration limitation, and a safe distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoretical innovation for future studies.
Using Problem-Based Learning to help Portuguese students make the Bologna transition
Directory of Open Access Journals (Sweden)
Manuel Cabral Reis
2013-08-01
Full Text Available The Bologna Declaration has opened a stage of big and deep changes in the internal university organization, external cooperation, teaching models and methods, among other., all over the European countries. Here we will present and discuss a pilot experience conducted at the Engineering Department of the University of Trás-os-Montes e Alto Douro, Portugal, during the second year of that transition period. In brief, we will present a set of non-mandatory courses proposed to the students of each individual syllabus, with one hundred hours duration, each, approximately seven hours/week, fifteen weeks long, with the permanent help of a specialized trainer to aid the students in their "homework". The formal bureaucratic transition is also presented. Design and implementation issues, supported on problem-based learning and experimental lab learning classes, final assessment results, as well as the opinion of the students, are presented and analyzed. We believe that this methodology helped to make the transition smoother to the students, but also to the teaching staff.
Oxygen Isotope Effect and Structural Phase Transitions in La2CuO4-Based Superconductors.
Crawford, M K; Farneth, W E; McCarronn, E M; Harlow, R L; Moudden, A H
1990-12-07
The oxygen isotope effect on the superconducting transition temperature (alpha(o)) varies as a function of x in La2-xSrxCuO(4) and La2-xBaxCuO(4), with the maximum alpha(o) values (alpha(o) >/= 0.5) found for x near 0.12. This unusual x dependence implies that the isotope effect is influenced by proximity to the Abma --> P4(2)/ncm structural phase transition in these systems. Synchrotron x-ray difaction measurements reveal little change in lattice parameters or orthorhombicity due to isotope exchange in strontium-doped materials where alpha(o) > 0.5, eliminating static structural distortion as a cause of the large isotope effects. The anomalous behavior of alpha(o) in both strontium- and barium-doped materials, in combination with the previously discovered Abma --> P4(2)/ncm structural phase-transition in La(1.88)B(0.12)CuO(4), suggests that an electronic contribution to the lattice instability is present and maximizes at approximately 1/8 hole per copper atom. These observations indicate a dose connection between hole doping of the Cu-O sheets, tilting instabilities of the CuO(6) octahedra, and superconductivity in La(2)CuO(4)-based superconductors.
Energy Technology Data Exchange (ETDEWEB)
Udhayakumari, Duraisamy [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Boobalan, Maria susai [Department of Chemistry, St. Joseph' s College (Autonomous), Tiruchirappalli 620002 (India); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)
2015-02-15
Heterocyclic ring based R1–R3 have been synthesized from the simple condensation method. R1–R3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R1–R3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R1–R3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R1 and R2 were also successfully demonstrated as a fluorescent probe for detecting Cu{sup 2+} ions in living cells. - highlights: • R1–R3 act as colorimetric and fluorescent sensors for metal ions. • Receptors (R1–R3) detect Cu{sup 2+} ions in aqueous solution at nanomolar levels. • R1 and R2 act as a fluorescent probe for detecting Cu{sup 2+} ions in living cells.
Analysis of Phase Transition in Traffic Flow based on a New Model of Driving Decision
Institute of Scientific and Technical Information of China (English)
PENG Yu; SHANG Hua-Yan; LU Hua-Pu
2011-01-01
Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton (CA) model, based on the driving decision (DD). In the DD model, a driver's decision is divided into three stages: decision-making, action, and result. The acceleration is taken as a decision variable and three core factors, i.e. distance between adjacent vehicles, their own velocity, and the preceding vehicle's velocity, are considered. Simulation results show that the DD model can simulate the synchronized flow effectively and describe the phase transition in traffic flow well. Further analyses illustrate that various density will cause the phase transition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle's velocity, the deceleration limitation, and a safe distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoretical innovation for future studies.
Liao, Chen-Tuo; Lin, Chia-Ying; Liu, Jen-Pei
2007-01-01
Microarray is one of the breakthrough technologies in the twenty-first century. Despite of its great potential, transition and realization of microarray technology into the clinically useful commercial products have not been as rapid as the technology could promise. One of the primary reasons is lack of agreement and poor reproducibility of the intensity measurements on gene expression obtained from microarray experiments. Current practices often use the testing the hypothesis of zero Pearson correlation coefficient to assess the agreement of gene expression levels between the technical replicates from microarray experiments. However, Pearson correlation coefficient is to evaluate linear association between two variables and fail to take into account changes in accuracy and precision. Hence, it is not appropriate for evaluation of agreement of gene expression levels between technical replicates. Therefore, we propose to use the concordance correlation coefficient to assess agreement of gene expression levels between technical replicates. We also apply the Generalized Pivotal Quantities to obtain the exact confidence interval for concordance coefficient. In addition, based on the concept of noninferiority test, a one-sided (1 - alpha) lower confidence limit for concordance correlation coefficient is employed to test the hypothesis that the agreement of expression levels of the same genes between two technical replicates exceeds some minimal requirement of agreement. We conducted a simulation study, under various combinations of mean differences, variability, and sample size, to empirically compare the performance of different methods for assessment of agreement in terms of coverage probability, expected length, size, and power. Numerical data from published papers illustrate the application of the proposed methods.
Gas monitoring data anomaly identification based on spatio-temporal correlativity analysis
Institute of Scientific and Technical Information of China (English)
Shi-song ZHU; Yun-jia WANG; Lian-jiang WEI
2013-01-01
Based on spatio-temporal correlativity analysis method,the automatic identification techniques for data anomaly monitoring of coal mining working face gas are presented.The asynchronous correlative characteristics of gas migration in working face airflow direction are qualitatively analyzed.The calculation method of asynchronous correlation delay step and the prediction and inversion formulas of gas concentration changing with time and space after gas emission in the air return roadway are provided.By calculating one hundred and fifty groups of gas sensors data series from a coal mine which have the theoretical correlativity,the correlative coefficient values range of eight kinds of data anomaly is obtained.Then the gas monitoring data anomaly identification algorithm based on spatio-temporal correlativity analysis is accordingly presented.In order to improve the efficiency of analysis,the gas sensors code rules which can express the spatial topological relations are suggested.The experiments indicate that methods presented in this article can effectively compensate the defects of methods based on a single gas sensor monitoring data.
Wieczorek, Katarzyna; Wiktorska, Magdalena; Sacewicz-Hofman, Izabela; Boncela, Joanna; Lewiński, Andrzej; Kowalska, M Anna; Niewiarowska, Jolanta
2017-10-01
Filamin A (FLNA) is actin filament cross-linking protein involved in cancer progression. Its importance in regulating cell motility is directly related to the epithelial to mesenchymal transition (EMT) of tumor cells. However, little is known about the mechanism of action of FLNA at this early stage of cancer invasion. Using immunochemical methods, we evaluated the levels and localization of FLNA, pFLNA[Ser2152], β1 integrin, pβ1 integrin[Thr788/9], FAK, pFAK[Y379], and talin in stably transfected HT29 adenocarcinoma cells overexpressing Snail and looked for the effect of Snail in adhesion and migration assays on fibronectin-coated surfaces before and after FLNA silencing. Our findings indicate that FLNA upregulation correlates with Snail-induced EMT in colorectal carcinoma. FLNA localizes in the cytoplasm and at the sites of focal adhesion (FA) of invasive cells. Silencing of FLNA inhibits Snail-induced cell adhesion, reduces the size of FA sites, induces the relocalization of talin from the cytoplasm to the membrane area and augments cell migratory properties. Our findings suggest that FLNA may not act as a classic integrin inhibitor in invasive carcinoma cells, but is involved in other pro-invasive pathways. FLNA upregulation, which correlates with cell metastatic properties, maybe an additional target for combination therapy in colorectal carcinoma tumor progression. Copyright © 2017 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
O. V. Slavina
2014-10-01
Full Text Available This article is an attempt to form a methodological foundation to explore the process of symbolic constructioning of reality in the political systems in a state of democratic transition. From the author’s point of view, such transit systems differ with the phenomenal features of transitional type of sign-symbolic context. There are the most significant of them: the confrontation of symbols of old and new, and the formation of public anxiety due to violation of the established values (significant symbols. The result of these processes is the emergence of the conditions for increasing capacity of perception of new symbols (re-symbolization, transmigration of symbolic forms, the appearance of spontaneous symbolic interactions in the community in the form of political protests, rallies, and panic. In this regard, it is necessary to understand the possibilities of the productive management of the collective consciousness in transit period to achieve mental solidarity of concrete society with democratic values. To perform this task, author develops the appropriate tools, which are based on the phenomenological theory, the Schutz’s theory of the constitution of the multiple realities, the philosophy of symbolic forms of E. Cassirer, the theory of social construction of P. Berger and T. Luckmann, as well as Lotman’s semiotic concept. It is concluded that in the collision of alternative symbolic projects of social order it is advisable to resort to controlled symbolization (the production of special symbolic codes of political legitimation. At the same time it is important to understand the mechanisms of auto- symbolization of the society (changing of mass consciousness by virtue of the progressive development of the political culture of people. Careless use of these technologies in the countries with non-consolidated democracy may become a factor of destabilization and formation of the conditions for authoritarian rollback.
Wang, Luman; Mo, Qiaochu; Wang, Jianxin
2015-01-01
Most current gene coexpression databases support the analysis for linear correlation of gene pairs, but not nonlinear correlation of them, which hinders precisely evaluating the gene-gene coexpression strengths. Here, we report a new database, MIrExpress, which takes advantage of the information theory, as well as the Pearson linear correlation method, to measure the linear correlation, nonlinear correlation, and their hybrid of cell-specific gene coexpressions in immune cells. For a given gene pair or probe set pair input by web users, both mutual information (MI) and Pearson correlation coefficient (r) are calculated, and several corresponding values are reported to reflect their coexpression correlation nature, including MI and r values, their respective rank orderings, their rank comparison, and their hybrid correlation value. Furthermore, for a given gene, the top 10 most relevant genes to it are displayed with the MI, r, or their hybrid perspective, respectively. Currently, the database totally includes 16 human cell groups, involving 20,283 human genes. The expression data and the calculated correlation results from the database are interactively accessible on the web page and can be implemented for other related applications and researches.
Solar diameter, eclipses and transits: the importance of ground-based observations
Sigismondi, Costantino
2012-01-01
According to satellite measurements the difference between polar and equatorial radius does not exceed 10 milliarcsec. These measurements are differential, and the absolute value of the solar diameter is not precisely known to a level of accuracy needed for finding variations during years or decades. Moreover the lifetime of a satellite is limited, and its calibration is not stable. This shows the need to continue ground-based observations of the Sun exploiting in particular the methods less affected by atmospheric turbulence, as the planetary transits and the total and annular eclipses. The state of art, the advantages and the limits of these two methods are here considered.
Photodetectors based on intersubband transitions using III-nitride superlattice structures
Energy Technology Data Exchange (ETDEWEB)
Hofstetter, Daniel; Baumann, Esther; Giorgetta, Fabrizio R; Theron, Ricardo [University of Neuchatel, 1 A.-L. Breguet, 2000 Neuchatel (Switzerland); Wu, Hong; Schaff, William J; Dawlaty, Jahan; George, Paul A; Eastman, Lester F; Rana, Farhan [Cornell University, Phillips Hall, Ithaca, NY 14853 (United States); Kandaswamy, Prem K; Leconte, Sylvain; Monroy, Eva [Equipe mixte CEA-CNRS Nanophysique et Semiconducteurs, INAC/SP2M/PSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)
2009-04-29
We review our recent progress on the fabrication of near-infrared photodetectors based on intersubband transitions in AlN/GaN superlattice structures. Such devices were first demonstrated in 2003, and have since then seen a quite substantial development both in terms of detector responsivity and high speed operation. Nowadays, the most impressive results include characterization up to 3 GHz using a directly modulated semiconductor laser and up to 13.3 GHz using an ultra-short pulse solid state laser.
A National Survey of School-Based Physical Therapists and Secondary Transition Practices
Doty, Antonette
2010-01-01
Researchers in the fields of physical therapy and special education transition have stated the need to explore how therapy programs impact the outcomes for transition-age students. Limited information exists to determine the level of involvement and role of physical therapists in secondary transition. In what transition activities are physical…
Directory of Open Access Journals (Sweden)
Weiren Luo
Full Text Available Expression of embryonic stem cells (ESCs markers (SOX2, OCT4, Nanog and Nestin is crucial for progression of various human malignancies. The purpose of this study was to investigate the expression and prognostic impact of these molecules in nasopharyngeal carcinoma (NPC patients by immunohistochemistry and immunofluorescence. In the present study, we found that the expression levels of SOX2, OCT4 and Nanog were highly expressed in NPC compared with the non-tumorous tissues. Furthermore, these proteins correlated significantly with several clinicalpathological factors and epithelial-mesenchymal transition (EMT-associated indicators (E-cadherin/N-cadherin and Snail. In multivariate analyses, high expression of OCT4 (P = 0.013 and Nanog (P = 0.040, but not that of SOX2, was associated with worse survival and had strongly independent prognostic effects. Of note, OCT4 and Nanog were more frequently located at the invasive front of tumors, and correlated significantly with various aggressive behaviors including T classification, N classification, M classification and clinical stage. Furthermore, patients with co-expression of OCT4 and Nanog in the invasive front had significantly worse survival (P = 0.005. Interestingly, at the invasive front, these molecules correlated significantly with Nestin expression in endothelial cells (P<0.001. These findings provide evidence that ESCs biomarkers OCT4 and Nanog serves as independent prognostic factors for NPC. Additionally, cancer cells in the invasive front of NPC acquiring ESCs-like features should be maintained by vascular niches.
Device modeling of superconductor transition edge sensors based on the two-fluid theory
Wang, Tian-Shun; Zhu, Qing-Feng; Wang, Jun-Xian; Li, Tie-Fu; Liu, Jian-She; Chen, Wei; Zhou, Xingxiang
2012-01-01
In order to support the design and study of sophisticated large scale transition edge sensor (TES) circuits, we use basic SPICE elements to develop device models for TESs based on the superfluid-normal fluid theory. In contrast to previous studies, our device model is not limited to small signal simulation, and it relies only on device parameters that have clear physical meaning and can be easily measured. We integrate the device models in design kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for versatile simulations of TES circuits. Comparing our simulation results with published experimental data, we find good agreement which suggests that device models based on the two-fluid theory can be used to predict the behavior of TES circuits reliably and hence they are valuable for assisting the design of sophisticated TES circuits.
Farlin, Julien; Maloszewski, Piotr; Schneider, Wilfried; Gallé, Tom
2014-05-01
Groundwater transit time is of interest in environmental studies pertaining to the transport of pollutants from its source to the aquifer outlet (spring or pumping well) or to an observation well. Different models have been proposed to describe the distribution of transit times within groundwatersheds, the most common being the dispersion model, the exponential-piston-flow model (EPM) both proposed by Maloszewski and Zuber (Maloszewski and Zuber, 1982) and the (two or three parameter) gamma model (Amin and Campana, 1996; Kirchner et al., 1999). Choosing which function applies best is a recurrent and controversial problem in hydrogeology. The object of this study is to revisit the applicability of the EPM for unconfined aquifers, and to introduce an alternative model based explicitly on groundwater hydraulics. The alternative model is based on the transit time of water from any point at the groundwater table to the aquifer outlet, and is used to calculate inversely the hydraulic parameters of a fractured unconfined sandstone aquifer from tritium measurements made in a series of contact springs. This model is compared to the EPM, which is usually adopted to describe the transit time distribution of confined and unconfined aquifers alike. Both models are tested against observations, and it is shown that the EPM fails the test for some of the springs, and generally seems to overestimate the older water component. Amin, I. E., and M. E. Campana (1996), A general lumped parameter model for the interpretation of tracer data and transit time calculation in hydrologic systems, Journal of Hydrology, 179, 1-21, doi: 10.1016/0022-1694(95)02880-3. Kirchner, J. W., X. H. Feng, and C. Neal (1999), Fractal stream chemistry and its implications for contaminant transport in catchments, Nature physics, 403, 524-527, doi: 10.1038/35000537. Maloszewski, P., and A. Zuber (1982), Determining the turnover time of groundwater systems with the aid of environmental tracers, Journal of
Hankel, Jennifer; Dewey, Susan; Martinez, Nina
2016-01-01
Through this article the authors examine data collected from 126 women seeking services at a transitional housing facility, primarily for women leaving street-based prostitution. Descriptive statistics on the women's ethno-racial identity, numbers of children, and experiences with violence are presented and analyzed to determine correlations and implications for social service providers working with this unique population of women. Nearly half of respondents are women of color, a majority have given birth to at least one child, and more than half are in a non-commercial intimate partnership, with a significant number reporting extensive experiences with violent trauma and abuse. Results indicate statistically significant differences in women's ethno-racial self-identification and their experiences of sex work and violence, as well as their marital status. Most notably, African-American and Hispanic women face the greatest and most diverse forms of intimate partner violence and negative sex industry experiences, with African-Americans more likely to engage in sex work as minors, be sexually abused as children, work for a pimp, and face physical assault and instances of sex trafficking. Results also support existing research showing correlations between traumatic childhood events and adult substance abuse, sexual assault, and other negative outcomes.
Modrzejewski, Marcin; Rajchel, Łukasz; Szczęśniak, Małgorzata M; Chałasiński, Grzegorz
2014-01-01
We present a physically motivated correlation functional belonging to the meta-generalized gradient approximation (meta-GGA) rung, which can be supplemented with long-range dispersion corrections without introducing double-counting of correlation contributions. The functional is derived by the method of constraint satisfaction, starting from an analytical expression for a real-space spin-resolved correlation hole. The model contains a position-dependent function that controls the range of the interelectronic correlations described by the semilocal functional. With minimal empiricism, this function may be adjusted so that the correlation model blends with a specific dispersion correction describing long-range contributions. For a preliminary assessment, our functional has been combined with the DFT-D3 dispersion correction and full Hartree-Fock (HF)-like exchange. Despite the HF-exchange approximation, its predictions compare favorably with reference interaction energies in an extensive set of non-covalently b...
Nieminen, Teemu; Lähteenmäki, Pasi; Tan, Zhenbing; Cox, Daniel; Hakonen, Pertti J.
2016-11-01
We present a microwave correlation measurement system based on two low-cost USB-connected software defined radio dongles modified to operate as coherent receivers by using a common local oscillator. Existing software is used to obtain I/Q samples from both dongles simultaneously at a software tunable frequency. To achieve low noise, we introduce an easy low-noise solution for cryogenic amplification at 600-900 MHz based on single discrete HEMT with 21 dB gain and 7 K noise temperature. In addition, we discuss the quantization effects in a digital correlation measurement and determination of optimal integration time by applying Allan deviation analysis.
Turner, Jake D; Biddle, Lauren I; Smart, Brianna M; Zellem, Robert T; Teske, Johanna K; Hardegree-Ullman, Kevin K; Griffith, Caitlin C; Leiter, Robin M; Cates, Ian T; Nieberding, Megan N; Smith, Carter-Thaxton W; Thompson, Robert M; Hofmann, Ryan; Berube, Michael P; Nguyen, Chi H; Small, Lindsay C; Guvenen, Blythe C; Richardson, Logan; McGraw, Allison; Raphael, Brandon; Crawford, Benjamin E; Robertson, Amy N; Tombleson, Ryan; Carleton, Timothy M; Towner, Allison P M; Walker-LaFollette, Amanda M; Hume, Jeffrey R; Watson, Zachary T; Jones, Christen K; Lichtenberger, Matthew J; Hoglund, Shelby R; Cook, Kendall L; Crossen, Cory A; Jorgensen, Curtis R; Thompson, James M Romine Alejandro R; Villegas, Christian F; Wilson, Ashley A; Sanford, Brent; Taylor, Joanna M
2016-01-01
Transits of exoplanets observed in the near-UV have been used to study the scattering properties of their atmospheres and possible star-planet interactions. We observed the primary transits of 15 exoplanets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-16b, HAT-P-22b, TrES-2b, TrES-4b, WASP-1b, WASP-12b, WASP-33b, WASP-36b, WASP-44b, WASP-48b, and WASP-77Ab) in the near-UV and several optical photometric bands to update their planetary parameters, ephemerides, search for a wavelength dependence in their transit depths to constrain their atmospheres, and determine if asymmetries are visible in their light curves. Here we present the first ground-based near-UV light curves for 12 of the targets (CoRoT-1b, GJ436b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-1b, WASP-33b, WASP-36b, WASP-48b, and WASP-77Ab). We find that none of the near-UV transits exhibit any non-spherical asymmetries, this result is consistent with recent theoretical predictions by Ben-Jaffel et al. and Turner et al. The multi-wavele...
Fasola, Shannon; Brudzinski, Michael R.; Ghouse, Noorulann; Solada, Katharine; Sit, Stefany; Cabral-Cano, Enrique; Arciniega-Ceballos, Alejandra; Kelly, Nicholas; Jensen, Kevin
2016-03-01
We examine the along-strike transition from flat to steeper subduction in Oaxaca, Mexico, to provide a better understanding of what controls the slab morphology. Prior studies have suggested the slab tends to tear along the transitions in dip as the slab rolls back. We determine the slab geometry based on local seismicity, nonvolcanic tremor (NVT), and slow slip utilizing a deployment of broadband seismometers and continuous GPS receivers distributed in and around Oaxaca. We construct depth contours of the subducting slab surface down to 100 km, which illustrate that the transition from flat to steeper subduction occurs rapidly via a sharper flexure than previously recognized. The prior catalog of NVT in Oaxaca is extended using the same method and additional stations that extend further west. The band of NVT follows the new slab contours, widening toward the west with the downdip extent gradually moving inland. The amount of NVT also correlates with the strength of an ultraslow-velocity layer. There are no gaps in seismicity, NVT, or slow slip across the rapid transition in slab dip, further supporting the notion that the slab is not currently torn in the updip region. We propose that the sharp flexure is possible in this region due to bending moment saturation that leads to greater curvature in both the downdip and along-strike directions. A similar set of observations in southern Peru suggests this is a viable alternative to tearing that accommodates the large strains from variable rates of slab rollback.
Estimation and Prediction of the Condition of the Vehicle Engine Based on the Correlation Dimension
Institute of Scientific and Technical Information of China (English)
LiuChun; ZhangLaibin; WangZhaohui
2004-01-01
This paper applies the fractal dimension as a characteristic to describe the engine's operating condition and its developmental trend. A correlation dimension is one of the quantities that are usually used to characterize a strange attractor. With the operation of the phase space reconstruction, respective correlation dimensions of a series of vibration signals obtained under different conditions are calculated to find the intrinsic relationship between the indicator and the operating condition. The experiment result shows that the correlation dimension is sensitive to the condition evolution and convenient for the identification of abnormal operational states. In advanced prognostic algorithm based on the BP neural network is then applied on the correlation dimensions to predict the short-term running conditions in order to avoid severe faults and realize in-time maintenance. Experimental results are presented to illustrate the proposed methodology.
A correlation based fault detection method for short circuits in battery packs
Xia, Bing; Shang, Yunlong; Nguyen, Truong; Mi, Chris
2017-01-01
This paper presents a fault detection method for short circuits based on the correlation coefficient of voltage curves. The proposed method utilizes the direct voltage measurements from the battery cells, and does not require any additional hardware or effort in modeling during fault detection. Moreover, the inherent mathematical properties of the correlation coefficient ensure the robustness of this method as the battery pack ages or is imbalanced in real applications. In order to apply this method online, the recursive moving window correlation coefficient calculation is adopted to maintain the detection sensitivity to faults during operation. An additive square wave is designed to prevent false positive detections when the batteries are at rest. The fault isolation can be achieved by identifying the overlapped cell in the correlation coefficients with fault flags. Simulation and experimental results validated the feasibility and demonstrated the advantages of this method.
Wavelet-based correlations of impedance cardiography signals and heart rate variability
Podtaev, Sergey; Dumler, Andrew; Stepanov, Rodion; Frick, Peter; Tziberkin, Kirill
2010-04-01
The wavelet-based correlation analysis is employed to study impedance cardiography signals (variation in the impedance of the thorax z(t) and time derivative of the thoracic impedance (- dz/dt)) and heart rate variability (HRV). A method of computer thoracic tetrapolar polyrheocardiography is used for hemodynamic registrations. The modulus of wavelet-correlation function shows the level of correlation, and the phase indicates the mean phase shift of oscillations at the given scale (frequency). Significant correlations essentially exceeding the values obtained for noise signals are defined within two spectral ranges, which correspond to respiratory activity (0.14-0.5 Hz), endothelial related metabolic activity and neuroendocrine rhythms (0.0095-0.02 Hz). Probably, the phase shift of oscillations in all frequency ranges is related to the peculiarities of parasympathetic and neuro-humoral regulation of a cardiovascular system.
Institute of Scientific and Technical Information of China (English)
Mohammad Mahdi Ghiasi
2012-01-01
Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature (HFT) under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.
A NEW SYSTEM DYNAMIC EXTREMUM SELF-SEARCHING METHOD BASED ON CORRELATION ANALYSIS
Institute of Scientific and Technical Information of China (English)
李嘉; 刘文江; 胡军; 袁廷奇
2003-01-01
Objective To propose a new dynamic extremum self-searching method, which can be used in industrial processes extremum optimum control systems, to overcome the disadvantages of traditional method. Methods This algorithm is based on correlation analysis. A pseudo-random binary signal m-sequence u(t) is added as probe signal in system input, construct cross-correlation function between system input and output, the next step hunting direction is judged by the differential sign. Results Compared with traditional algorithm such as step forward hunting method, the iterative efficient, hunting precision and anti-interference ability of the correlation analysis method is obvious over the traditional algorithm. The computer simulation experimental given illustrate these viewpoints. Conclusion The correlation analysis method can settle the optimum state point of device operating process. It has the advantage of easy condition , simple calculate process.
Cross-correlation function based multipath mitigation technique for cosine-BOC signals
Institute of Scientific and Technical Information of China (English)
Huihua Chen; Weimin Jia; Minli Yao
2013-01-01
We propose a new multipath mitigation technique based on cross-correlation function for the new cosine phased binary off-set carrier (cosine-BOC) modulated signals, which wil most likely be employed in both European Galileo system and Chinese Com-pass system. This technique is implemented to create an optimum cross-correlation function via designing the modulated symbols of the local signal. And the structure of the code tracking loop for cosine-BOC signals is quite simple including only two real correla-tors. Results demonstrate that the technique efficiently eliminates the ranging errors in the medium and long multipath regions with respect to the conventional receiver correlation techniques.
Ajayi, Idowu; Aremu, Ademola; Olajide, Abimbola; Bello, Tope; Olajide, Folake; Adetiloye, Victor
2013-01-01
Benign prostatic hyperplasia is a common disease of ageing men worldwide. Though transrectal ultrasonography (TRUS) is the standard in most parts of the world in evaluation of benign prostatic hyperplasia (BPH), it is rarely done in some less developed countries because of non availability of appropriate probes and or specialists. Transabdominal ultrasonography (TAUS) remains the mainstay in these areas. Some controversies still exist in literature about the accuracy of TAUS evaluation of prostatic volume in patients with BPH. This study aimed at comparing the transition zone volume estimation of the prostate on transrectal and transabdominal ultrasound with post-operative enucleated adenoma volume in Nigeria patients with BPH and to suggest better predictor of prostate volume in evaluation of BPH. Forty-six (46) patients with lower urinary tract symptoms due to BPH attending the urologic clinic were evaluated ultrasonographically and eventually managed with open surgery (prostatectomy) after due counselling. The post operative samples were weighted using a sensitive top loading weighing balance and converted to volume. Since the specific gravity of the prostate is equivalent to that of water,the weight is the same as volume. Patients' ages ranged between 59 and 90 years with a peak age incidence at seventh decade. Transition Zone (TZ) volume estimation on both transrectal and transabdominal ultrasound showed positive correlation with the post operative enucleated adenoma(r = 0.594, p < 0.001) but the transrectal method was more accurate. There was no significant relationship between the TZ volume and patients' symptoms(r = 0.491, p = 0.007). Both TRUS and TAUS are comparable at TZ volume estimation and therefore TAUS can be utilized in regions where intracavitary probes and or the expertise is/are not available.
Babchishin, Kelly M; Helmus, Leslie-Maaike
2016-09-01
Correlations are the simplest and most commonly understood effect size statistic in psychology. The purpose of the current paper was to use a large sample of real-world data (109 correlations with 60,415 participants) to illustrate the base rate dependence of correlations when applied to dichotomous or ordinal data. Specifically, we examined the influence of the base rate on different effect size metrics. Correlations decreased when the dichotomous variable did not have a 50 % base rate. The higher the deviation from a 50 % base rate, the smaller the observed Pearson's point-biserial and Kendall's tau correlation coefficients. In contrast, the relationship between base rate deviations and the more commonly proposed alternatives (i.e., polychoric correlation coefficients, AUCs, Pearson/Thorndike adjusted correlations, and Cohen's d) were less remarkable, with AUCs being most robust to attenuation due to base rates. In other words, the base rate makes a marked difference in the magnitude of the correlation. As such, when using dichotomous data, the correlation may be more sensitive to base rates than is optimal for the researcher's goals. Given the magnitude of the association between the base rate and point-biserial correlations (r = -.81) and Kendall's tau (r = -.80), we recommend that AUCs, Pearson/Thorndike adjusted correlations, Cohen's d, or polychoric correlations should be considered as alternate effect size statistics in many contexts.
Refinement of arrival-time picks using a cross-correlation based workflow
Akram, Jubran; Eaton, David W.
2016-12-01
We propose a new iterative workflow based on cross-correlation for improved arrival-time picking on microseismic data. In this workflow, signal-to-noise ratio (S/N) and polarity weighted stacking are used to minimize the effect of S/N and polarity fluctuations on the pilot waveform computation. We use an exhaustive search technique for polarity estimation through stack power maximization. We use pseudo-synthetic and real microseismic data from western Canada in order to demonstrate the effectiveness of proposed workflow relative to Akaike information criterion (AIC) and a previously published cross-correlation based method. The pseudo-synthetic microseismic waveforms are obtained by introducing Gaussian noise and polarity fluctuations into waveforms from a high S/N microseismic event. We find that the cross-correlation based approaches yield more accurate arrival-time picks as compared to AIC for low S/N waveforms. AIC is not affected by waveform polarities as it works on individual receiver levels whereas the accuracy of existing cross-correlation method decreases in spite of using envelope correlation. We show that our proposed workflow yields better and consistent arrival-time picks regardless of waveform amplitude and polarity variations within the receiver array. After refinement, the initial arrival-time picks are located closer to the best estimated manual picks.
Correlation of self-assessment with attendance in an evidence-based medicine course.
Ramirez, Beatriz U
2015-12-01
In previous studies, correlations between attendance and grades in lectures have given variable results and, when statistically significant, the correlation has been weak. In some studies, a sex effect has been reported. Lectures are a teacher-centered learning activity. Therefore, it appeared interesting to evaluate if a stronger correlation between attendance and grades would occur in a face-to-face "evidence-based medicine" course with few lectures and more time dedicated to active learning methods. Small-group work and peer learning were used to foster deep learning and to engage students in their own learning process. Most of the time, students worked in small groups solving contextualized problems and critically analyzing the quality of published medical literature. Peer learning was also developed in collaborative evaluations, and constant feedback was provided. Therefore, it was hypothesized that high attenders would develop a higher self-perception of learning and obtain higher marks than low attenders. Student self-perceptions of their capacity to apply evidence-based medicine were measured by the application of an online self-assessment survey, and objective learning was measured as the grades obtained in a final accumulative individual test. It was found that male students obtained higher grades and were more confident in their achievements than their female peers, despite male and female student attendance being similar. In addition, attendance was correlated with the perceived capacity to apply evidence-based medicine only in male students and was not correlated with academic outcome.
Matroidal Structure of Rough Sets Based on Serial and Transitive Relations
Directory of Open Access Journals (Sweden)
Yanfang Liu
2012-01-01
Full Text Available The theory of rough sets is concerned with the lower and upper approximations of objects through a binary relation on a universe. It has been applied to machine learning, knowledge discovery, and data mining. The theory of matroids is a generalization of linear independence in vector spaces. It has been used in combinatorial optimization and algorithm design. In order to take advantages of both rough sets and matroids, in this paper we propose a matroidal structure of rough sets based on a serial and transitive relation on a universe. We define the family of all minimal neighborhoods of a relation on a universe and prove it satisfies the circuit axioms of matroids when the relation is serial and transitive. In order to further study this matroidal structure, we investigate the inverse of this construction: inducing a relation by a matroid. The relationships between the upper approximation operators of rough sets based on relations and the closure operators of matroids in the above two constructions are studied. Moreover, we investigate the connections between the above two constructions.
A College-Level Inquiry-Based Laboratory Activity on Transiting Planets
McConnell, Nicholas J; Strubbe, Linda E; Moth, Pimol; Montgomery, Ryan M; Raschke, Lynne M; Hunter, Lisa; Goza, Barbara
2010-01-01
We have designed an inquiry-based laboratory activity on transiting extrasolar planets for an introductory college-level astronomy class. The activity was designed with the intent of simultaneously teaching science process skills and factual content about transits and light curves. In the activity, groups of two to four students each formulate a specific science question and design and carry out an investigation using a table-top model of a star and orbiting planet. Each group then presents their findings to other students in their class. In a final presentation, the instructors integrate students' findings with a summary of how measured light curves indicate properties of planetary systems. The activity debuted at Hartnell College in November 2009 and has also been adapted for a lecture-based astronomy course at U.C. Santa Cruz. We present the results of student surveys before and after the astronomy course at Hartnell and discuss how well our activity promotes students' confidence and identity as scientists...
Reliability sensitivity-based correlation coefficient calculation in structural reliability analysis
Yang, Zhou; Zhang, Yimin; Zhang, Xufang; Huang, Xianzhen
2012-05-01
The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored, which cannot actually reflect the effects of parameter uncertainties on reliability. To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view, the theory principle of the problem is established based on the results of the reliability sensitivity, and the criterion of correlation among random variables is shown. The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed. Numerical studies have shown the following results: (1) If the sensitivity value of correlation coefficient ρ is less than (at what magnitude 0.000 01), then the correlation could be ignored, which could simplify the procedure without introducing additional error. (2) However, as the difference between ρ s, that is the most sensitive to the reliability, and ρ R , that is with the smallest reliability, is less than 0.001, ρ s is suggested to model the dependency of random variables. This could ensure the robust quality of system without the loss of safety requirement. (3) In the case of | E abs|>0.001 and also | E rel|>0.001, ρ R should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis. Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design.
Green Grown- Bases of Bioeconomy Models in Correlation with Danubian Projects
Directory of Open Access Journals (Sweden)
Iudith Ipate
2015-08-01
Full Text Available The objective of the our study is to provide defined measureable indicators at the Romanian region level that to possibility over time transition to low carbon-economic and developed the bio-economic models in correlation with economic development in this areas. For implementing the global bio-economy models is important to develop the innovative research in cooperation with regional entrepreneur. In this context must to implementing the projects in cooperation with local authority, promoting common action to overcome the physical and socio-cultural barriers, and to better exploit the opportunities offered by the development of the cross-border area for a mid-longterm sustainable growth. In our research we developed one model using the series from water exploitation index (WEI, GDP per capita, CO2 emissions per capita (2emision and population growth – POP.
Karjee, Jyotirmoy
2011-01-01
Objective: The main objective of this paper is to construct a distributed clustering algorithm based upon spatial data correlation among sensor nodes and perform data accuracy for each distributed cluster at their respective cluster head node. Design Procedure/Approach: We investigate that due to deployment of high density of sensor nodes in the sensor field, spatial data are highly correlated among sensor nodes in spatial domain. Based on high data correlation among sensor nodes, we propose a non -overlapping irregular distributed clustering algorithm with different sizes to collect most accurate or precise data at the cluster head node for each respective distributed cluster. To collect the most accurate data at the cluster head node for each distributed cluster in sensor field, we propose a Data accuracy model and compare the results with Information accuracy model. Finding: Simulation results shows that our propose Data accuracy model collects more accurate data and gives better performance than Informati...
Characteristic analysis on UAV-MIMO channel based on normalized correlation matrix.
Gao, Xi jun; Chen, Zi li; Hu, Yong Jiang
2014-01-01
Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication.
Zhan, Qin; Yuan, Yuan; Fan, Xiangtao; Huang, Jianyong; Xiong, Chunyang; Yuan, Fan
2016-06-01
Digital image correlation (DIC) is essentially implicated in a class of inverse problem. Here, a regularization scheme is developed for the subset-based DIC technique to effectively inhibit potential ill-posedness that likely arises in actual deformation calculations and hence enhance numerical stability, accuracy and precision of correlation measurement. With the aid of a parameterized two-dimensional Butterworth window, a regularized subpixel registration strategy is established, in which the amount of speckle information introduced to correlation calculations may be weighted through equivalent subset size constraint. The optimal regularization parameter associated with each individual sampling point is determined in a self-adaptive way by numerically investigating the curve of 2-norm condition number of coefficient matrix versus the corresponding equivalent subset size, based on which the regularized solution can eventually be obtained. Numerical results deriving from both synthetic speckle images and actual experimental images demonstrate the feasibility and effectiveness of the set of newly-proposed regularized DIC algorithms.
Thiosemicabazone based fluorescent chemosensor for transition metal ions in aqueous medium
Energy Technology Data Exchange (ETDEWEB)
Udhayakumari, Duraisamy; Suganya, Sivalingam; Velmathi, Sivan, E-mail: velmathis@nitt.edu
2013-09-15
Highly efficient fluorescent chemosensors for metal ions have been synthesized by using thiosemicarbazide and aromatic aldehydes. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This is the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex were confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg{sup 2+}, Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+} and Sn{sup 2+} ions is due to the inhibition of photoinduced electron transfer mechanism whereas, quenching of fluorescence is attributed to the photoinduced electron transfer mechanism in case of Cu{sup 2+} and Mn{sup 2+} ions. -- Graphical abstract: Three highly sensitive aromatic thiosemicarbazones act as a fluorescent chemosensor for cations. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This represents the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex was confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg{sup 2+} , Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+} and Sn{sup 2+} ions is due to the inhibition of photoinduced electron transfer whereas, in the case of Cu{sup 2+} and Mn{sup 2+} ions quenching of fluorescence occurring is attributed to the photoinduced electron transfer mechanism. Highlights: • The receptors were synthesized and studied for its optical/fluorescence emission properties. • R1+Zn{sup 2+}/Co{sup 2+}/Ni{sup 2+} and R2+Hg{sup 2+}/Sn{sup 2+} exhibits fluorescence enhancement via inhibition of PET. • R1+Cu{sup 2+} and R3+Mn{sup 2+} exhibits fluorescence quenching via PET mechanism.
Directory of Open Access Journals (Sweden)
Keranmu Xielifuguli
2014-01-01
Full Text Available People often make decisions based on sensitivity rather than rationality. In the field of biological information processing, methods are available for analyzing biological information directly based on electroencephalogram: EEG to determine the pleasant/unpleasant reactions of users. In this study, we propose a sensitivity filtering technique for discriminating preferences (pleasant/unpleasant for images using a sensitivity image filtering system based on EEG. Using a set of images retrieved by similarity retrieval, we perform the sensitivity-based pleasant/unpleasant classification of images based on the affective features extracted from images with the maximum entropy method: MEM. In the present study, the affective features comprised cross-correlation features obtained from EEGs produced when an individual observed an image. However, it is difficult to measure the EEG when a subject visualizes an unknown image. Thus, we propose a solution where a linear regression method based on canonical correlation is used to estimate the cross-correlation features from image features. Experiments were conducted to evaluate the validity of sensitivity filtering compared with image similarity retrieval methods based on image features. We found that sensitivity filtering using color correlograms was suitable for the classification of preferred images, while sensitivity filtering using local binary patterns was suitable for the classification of unpleasant images. Moreover, sensitivity filtering using local binary patterns for unpleasant images had a 90% success rate. Thus, we conclude that the proposed method is efficient for filtering unpleasant images.
Liu, An-Nuo; Wang, Lu-Lu; Li, Hui-Ping; Gong, Juan; Liu, Xiao-Hong
2016-11-22
The literature on posttraumatic growth (PTG) is burgeoning, with the inconsistencies in the literature of the relationship between PTG and posttraumatic stress disorder (PTSD) symptoms becoming a focal point of attention. Thus, this meta-analysis aims to explore the relationship between PTG and PTSD symptoms through the Pearson correlation coefficient. A systematic search of the literature from January 1996 to November 2015 was completed. We retrieved reports on 63 studies that involved 26,951 patients. The weighted correlation coefficient revealed an effect size of 0.22 with a 95% confidence interval of 0.18 to 0.25. Meta-analysis provides evidence that PTG may be positively correlated with PTSD symptoms and that this correlation may be modified by age, trauma type, and time since trauma. Accordingly, people with high levels of PTG should not be ignored, but rather, they should continue to receive help to alleviate their PTSD symptoms.
Indian Academy of Sciences (India)
SUNDARAMURTHY SANTHA LAKSHMI; KANNAPPAN GEETHA; P MAHADEVI
2016-07-01
A series of four new Schiff base transition metal complexes [Co(II), Ni(II), Cu(II) and Zn(II)] derived from N-(salicylidene)-L-alanine and N,N,N',N'-tetramethylethylene-1,2-diamine (tmen) were designed, synthesized and tested for larvicidal activity against Culex quinquefasciatus, the southern house mosquito, which is the primary vector of St. Louis encephalitis virus and West Nile virus. All the complexes were characterized by physicochemical and spectral studies such as UV-Visible, FTIR, and EPR. The X-ray crystallographic analysis of Ni(II) complex revealed that, Ni(II) cation is surrounded by nitrogen and oxygen atoms from the Schiff base ligand, the oxygen atom of a water molecule, and two nitrogen atoms from tmen. Intermolecularhydrogen bonding stabilizes the Ni(II) complex. Results indicated that all the complexes exhibited higher mosquito larvicidal activity against C. quinquefasciatus.
High Power, Room Temperature Terahertz Emitters Based on Dopant Transitions in 6H-Silicon Carbide
Institute of Scientific and Technical Information of China (English)
James Kolodzey; Guang-Chi Xuan; Peng-Cheng Lv; Nathan Sustersic; Xin Ma
2014-01-01
Electrically pumped high power terahertz (THz) emitters that operated above room temperature in a pulse mode were fabricated from nitrogen-doped n-type 6H-SiC. The emission spectra had peaks centered on 5 THz and 12 THz (20 meV and 50 meV) that were attributed to radiative transitions of excitons bound to nitrogen donor impurities. Due to the relatively deep binding energies of the nitrogen donors, above 100 meV, and the high thermal conductivity of the SiC substrates, the THz output power and operating temperature were significantly higher than previous dopant based emitters. With peak applied currents of a few amperes, and a top surface area of 1 mm2, the device emitted up to 0.5 mW at liquid nitrogen temperature (77 K), and tens of microwatts up to 333 K. This result is the highest temperature of THz emission reported from impurity-based emitters.
Berndsen, M.; van der Pligt, J.; Spears, R.; McGarty, C.
1996-01-01
Examined the effects of expectations and stimulus information on the perception of illusory correlation. Expectation was manipulated by telling 154 psychology students that group B behaved more negatively than group A vs by providing no expectation. Ss were also provided with information contained
Alseddiqi, M.; Mishra, R.; Pislaru, C.
2012-05-01
The paper presents the results from a quality framework to measure the effectiveness of a new engineering course entitled 'school-based learning (SBL) to work-based learning (WBL) transition module' in the Technical and Vocational Education (TVE) system in Bahrain. The framework is an extended version of existing information quality frameworks with respect to pedagogical and technological contexts. It incorporates specific pedagogical and technological dimensions as per the Bahrain modern industry requirements. Users' views questionnaire on the effectiveness of the new transition module was distributed to various stakeholders including TVE teachers and students. The aim was to receive critical information in diagnosing, monitoring and evaluating different views and perceptions about the effectiveness of the new module. The analysis categorised the quality dimensions by their relative importance. This was carried out using the principal component analysis available in SPSS. The analysis clearly identified the most important quality dimensions integrated in the new module for SBL-to-WBL transition. It was also apparent that the new module contains workplace proficiencies, prepares TVE students for work placement, provides effective teaching and learning methodologies, integrates innovative technology in the process of learning, meets modern industrial needs, and presents a cooperative learning environment for TVE students. From the principal component analysis finding, to calculate the percentage of relative importance of each factor and its quality dimensions, was significant. The percentage comparison would justify the most important factor as well as the most important quality dimensions. Also, the new, re-arranged quality dimensions from the finding with an extended number of factors tended to improve the extended version of the quality information framework to a revised quality framework.
Fast region-based object detection and tracking using correlation of features
CSIR Research Space (South Africa)
Senekal, F
2010-11-01
Full Text Available A new method for object detection using region based characteristics is proposed. The method uses correlation between features over a region as a descriptor for the region. It is shown that this region descriptor can be successfully applied...
DEFF Research Database (Denmark)
Relano-Iborra, Helia; May, Tobias; Zaar, Johannes
-based Envelope Power Spectrum Model (mr-sEPSM) [2], combined with the correlation back-end of the Short-Time Objective Intelligibility measure (STOI) [3]. The sEPSMcorr can accurately predict NH data for a broad range of listening conditions, e.g., additive noise, phase jitter and ideal binary mask processing....
Volatility and correlation-based systemic risk measures in the US market
Civitarese, Jamil
2016-10-01
This paper deals with the problem of how to use simple systemic risk measures to assess portfolio risk characteristics. Using three simple examples taken from previous literature, one based on raw and partial correlations, another based on the eigenvalue decomposition of the covariance matrix and the last one based on an eigenvalue entropy, a Granger-causation analysis revealed some of them are not always a good measure of risk in the S&P 500 and in the VIX. The measures selected do not Granger-cause the VIX index in all windows selected; therefore, in the sense of risk as volatility, the indicators are not always suitable. Nevertheless, their results towards returns are similar to previous works that accept them. A deeper analysis has shown that any symmetric measure based on eigenvalue decomposition of correlation matrices, however, is not useful as a measure of "correlation" risk. The empirical counterpart analysis of this proposition stated that negative correlations are usually small and, therefore, do not heavily distort the behavior of the indicator.
Parks, Lauren K.; Hill, Dina E.; Thoma, Robert J.; Euler, Matthew J.; Lewine, Jeffrey D.; Yeo, Ronald A.
2009-01-01
Although many studies have compared the brains of normal controls and individuals with autism, especially older, higher-functioning individuals with autism, little is known of the neural correlates of the vast clinical heterogeneity characteristic of the disorder. In this study, we used voxel-based morphometry (VBM) to examine gray matter…