作者:
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellan;Abudinen, F.;Ackernley, T.;...
期刊:
PHYSICAL REVIEW D,2023年108(1) ISSN:2470-0010
通讯作者:
Leite, JBD
作者机构:
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Snoch, A.; van Beuzekom, M.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Baptista de Souza Leite, J.; De Freitas Carneiro Da Graca, U.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Leite, JBD; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Otalora Goicochea, J. M.; De Paula, L.; Nasteva, I.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Grieser, N. A.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
通讯机构:
[Leite, JBD ] C;Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.
摘要:
Resonant structures in the dipion mass spectrum from & chi;c1(3872) & RARR; & pi;+& pi;-J=& psi; decays, produced via B+ & RARR; K+& chi;c1(3872) decays, are analyzed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1. A sizeable contribution from the isospin conserving & chi;c1(3872) & RARR; & omega;J=& psi; decay is established for the first time, (21.4 & PLUSMN; 2.3 & PLUSMN; 2.0)%, with a significance of more than 7.1 & sigma;. The amplitude of isospin violating decay, & chi;c1(3872) & RARR; & rho;0J=& psi;, relative to isospin conserving decay, & chi;c1(3872) & RARR; & omega;J=& psi;, is properly determined, and it is a factor of 6 larger than expected for a pure charmonium state.
摘要:
Cognitive radio (CR) acts as a significant player in enhancing the spectral efficiency (SE) of wireless telecommunications; simultaneously, the intelligent reflecting surface (IRS) technique is a valid technique for increasing the confidentiality properties of wireless telecommunications systems through the modulation of the amplitude and phase shift of the channel. Therefore, we take into consideration an IRS-assisted multiple-input single-output (MISO) CR system to raise the confidentiality rate, which is composed of a primary network with a primary receiver (PR) and an eavesdropping link, as well as a secondary network with a secondary receiver (SR) and SR transmitter (SR-TX). In particular, we minimize the SR’s transmit power under the interference temperature (IT) and confidentiality capacity constraints via the joint optimization of the beamforming vector and artificial noise (AN) constraint matrix at SR-TX together with the phase shift matrix of IRS. Numerical outcomes indicate that various transmit antenna values and the IRS element numbers at SR-TX can greatly reduce transmit power while assuring secure communication.
摘要:
Herein, we aimed to solve the problem of difficulty in filtering the noise components in the monitoring of strain on wind turbine blades using fiber bragg grating, a denoising method based on parameter-optimized variational mode decomposition (VMD) is proposed. This method uses the minimum envelope entropy as the fitness function and the slime mould algorithm for self-adaptive optimization to find the optimal combination of modal decomposition components K and the quadratic penalty factor alpha of VMD. The optimized VMD was used to decompose the strain data of wind turbine blades over time into K intrinsic mode components, and the noise mode was removed using the sample entropy to obtain the effective signal. The proposed method was compared to ensemble empirical mode decomposition and complementary ensemble empirical mode decomposition using the simulated signals and engineering data. The experimental results show that the proposed method can effectively remove noise from the strain data of wind turbine blades and has better denoising performance than the other two methods, which provides a reliable basis for analyzing the strain data of wind turbine blades.
作者机构:
[Ketel, T.; Tuning, N.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Aaij, R; Snoch, A.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; van Veghel, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Baptista de Souza Leite, J.; De Freitas Carneiro Da Graca, U.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Otalora Goicochea, J. M.; Gomes, A.; De Paula, L.; Nasteva, I.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys IHEP, Beijing, Peoples R China.
摘要:
The ratios of branching fractions R(D^{*})≡B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}μ^{-}ν[over ¯]_{μ}) and R(D^{0})≡B(B^{-}→D^{0}τ^{-}ν[over ¯]_{τ})/B(B^{-}→D^{0}μ^{-}ν[over ¯]_{μ}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ^{-}→μ^{-}ν_{τ}ν[over ¯]_{μ}. The measured values are R(D^{*})=0.281±0.018±0.024 and R(D^{0})=0.441±0.060±0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=-0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.
作者机构:
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Snoch, A.; van Beuzekom, M.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Baptista de Souza Leite, J.; De Freitas Carneiro Da Graca, U.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Leite, JBD; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Otalora Goicochea, J. M.; De Paula, L.; Nasteva, I.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Grieser, N. A.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
通讯机构:
[Leite, JBD ] C;Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.
摘要:
The branching fraction of the rare decay Lambda(0 )(b)-> Lambda(1520)mu(+)mu(-) is measured for the first time, in the squared dimuon mass intervals q(2), excluding the J/psi and psi(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb(-1). The result in the highest q(2) interval, q(2) > 15.0 GeV2/c(4), where theoretical predictions have the smallest model dependence, agrees with the predictions.
摘要:
Sportsmanship is a core characteristic of competitive sports. To determine the factors related to sportsmanship and explore effective strategies to maintain sportsmanship in adolescent athletes, the present study examined the relationship between anxiety and sportsmanship in adolescent athletes and evaluated the potential mediating roles of athlete burnout and exercise cognition. In this study, 1,544 adolescent athletes (852 boys and 692 girls) with an average age of 14.43 years (SD = 1.92) were enrolled. The analyses showed that there was a significant correlation between state anxiety, trait anxiety, athlete burnout, exercise cognition, and sportsmanship. Additionally, state and trait anxiety were associated with lower levels of sportsmanship, and athlete burnout and exercise cognition played multiple mediating roles in the relationship between anxiety and sportsmanship. These findings suggest that anxiety is a plausible explanation for sportsmanship. Adolescent athletes with high levels of trait or state anxiety are more likely to experience athlete burnout, have poorer levels of exercise cognition, and display less sportsmanship.
作者机构:
[Yang, Ya-Dong; Zheng, Dong-Hui; Kong, Ya-Ru; Li, Xin-Qiang] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;[Yang, Ya-Dong; Zheng, Dong-Hui; Kong, Ya-Ru; Li, Xin-Qiang] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;[Lai, Li-Fen] Shangrao Normal Univ, Sch Phys & Elect Informat, Shangrao 334001, Peoples R China.;[Li, Xin-Qiang] Peking Univ, Ctr High Energy Phys, Beijing 100871, Peoples R China.;[Yan, Xin-Shuai; Yang, Ya-Dong; Yan, XS] Henan Normal Univ, Inst Particle & Nucl Phys, Xinxiang 453007, Henan, Peoples R China.
通讯机构:
[Yan, XS ] H;Henan Normal Univ, Inst Particle & Nucl Phys, Xinxiang 453007, Henan, Peoples R China.
摘要:
The absence of semitauonic decays of charmed hadrons makes the decay processes mediated by the quark-level c -> d tau thorn nu tau transition inadequate for probing a generic new physics (NP) with all kinds of Dirac structures. To fill in this gap, we consider in this paper the quasielastic neutrino scattering process nu tau thorn n -> tau- thorn Lambda c, and propose searching for NP through the polarizations of the tau lepton and the Lambda c baryon. In the framework of a general low-energy effective Lagrangian, we perform a comprehensive analysis of the (differential) cross sections and polarization vectors of the process both within the Standard Model and in various NP scenarios, and scrutinize possible NP signals. We also explore the influence on our findings due to the uncertainties and the different parametrizations of the Lambda c -> N transition form factors, and show that they have become one of the major challenges to further constrain possible NP through the quasielastic scattering process.
作者:
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellan;Abudinen, F.;Ackernley, T.;...
期刊:
Journal of High Energy Physics,2023年2023(7):1-26 ISSN:1029-8479
通讯作者:
Aaij, R
作者机构:
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Aaij, R; Snoch, A.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Da Graca, U. De Freitas Carneiro; Massafferri, A.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Torres, M. Cruz; Machado, D. Torres; Gomes, A.; dos Reis, A. C.; Leite, J. Baptista de Souza] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[De Paula, B. Souza; Lopes, J. H.; Polycarpo, E.; Gandelman, M.; Rangel, M. S.; Hicheur, A.; Gomes, A.; Garcia, L. Meyer; Rodrigues, F. Ferreira; De Paula, L.; Nasteva, I.; Amato, S.; Goicochea, M. Otalora; De Almeida, F. L. Souza] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
摘要:
The polarimeter vector field for multibody decays of a spin-half baryon is introduced as a generalisation of the baryon asymmetry parameters. Using a recent amplitude analysis of the Λc+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\Lambda}_c^{+} $$\end{document} → pK−π+ decay performed at the LHCb experiment, we compute the distribution of the kinematic-dependent polarimeter vector for this process in the space of Mandelstam variables to express the polarised decay rate in a model-agnostic form. The obtained representation can facilitate polarisation measurements of the Λc+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\Lambda}_c^{+} $$\end{document} baryon and eases inclusion of the Λc+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\Lambda}_c^{+} $$\end{document}→ pK−π+ decay mode in hadronic amplitude analyses.
作者机构:
[Gong, Xiaofeng] Guizhou Sci & Technol Informat Ctr, Guiyang 550002, Peoples R China.;[Xiang, Wenchang; Cai, Yanbing] Guizhou Univ Finance & Econ, Guizhou Key Lab Big Data Stat Anal, Guiyang 550025, Peoples R China.;[Xiang, Wenchang; Cai, Yanbing] Guizhou Univ Finance & Econ, Guizhou Key Lab Phys & Related Areas, Guiyang 550025, Peoples R China.;[Zhou, Daicui] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[Zhou, Daicui] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
gluon saturation;high energy heavy ion collisions;small-x physics
摘要:
To obtain a reasonable description of the hadron production at the LHC energies, the impact parameter dependent saturation model is modified by inclusion of an anomalous dimension γ, which controls the slope of the scattering amplitude in the transition from the dilute region to the saturation region. We calculate the transverse momentum distribution and nuclear modification factor of the π0 and charged hadrons with the improved model, and the results are consistent with measurements performed at the LHC. Moreover, we use the original impact parameter dependent model to study the aforementioned measurements performed at the LHC by adjusting its parameters. We find that the improved model is more consistent with the experimental data than the original one, as the anomalous dimension plays a significant role in the suppression of the evolution of the scattering amplitude.
作者:
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellan;Abudinen, F.;Ackernley, T.;...
期刊:
中国物理C,2023年47(9):093002 ISSN:1674-1137
通讯作者:
Leite, JBD
作者机构:
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Snoch, A.; van Beuzekom, M.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Baptista de Souza Leite, J.; De Freitas Carneiro Da Graca, U.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Leite, JBD; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Otalora Goicochea, J. M.; De Paula, L.; Nasteva, I.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Zhu, X.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Li, T.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Grieser, N. A.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
通讯机构:
[Leite, JBD ] C;Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.
关键词:
W/Z boson;rare decay;upper limit of branching fraction
摘要:
A search for the rare decays W+ -> D-s(+)gamma and Z -> D-0 gamma and is performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 2.0fb(-1). No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W+ -> mu(+)nu and Z ->mu(+)mu(-)decays as normalization channels. The upper limits are and at 95% confidence level for W+ -> D-s(+)gamma and Z -> D-0 gamma the and decay modes, respectively. This is the first reported search for Z -> D-0 gamma the decay, while the upper limit on the Z -> D-0 gamma branching fraction improves upon the previous best limit.
摘要:
Energy absorption and consumption are essential for the activity of single neurons and neuronal networks. The synchronization mode transition and energy dependence in a delay-coupled FitzHugh-Nagumo (FHN) neuronal system driven by chaotic activity are investigated in this paper. With the change of chaotic current intensity, it was found that the synchronization mode of coupled neurons undergoes synchronous state, transition state, anti-phase state, alternating asynchronous and anti-phase state, and chaotic current-induced chaotic state. The Hamiltonian energy is much dependent on the synchronization mode of coupled neurons. The synchronization mode and the Hamiltonian energy of coupled neurons can be modulated by chaotic current intensity, coupling strength and time delay. The introduction of the time delay induces the system to become bistable state. Chaotic current as an external force induced transitions between the synchronous and anti-phase states. Coupling strength is an intrinsic property of the system and can change the properties of the bistable state. Furthermore, the synchronous and anti-phase states appear intermittently with the increasing of time delay. A chained neuronal network is used to prove that the synchronization mode transition of the system of multiple neurons is similar to the two neurons. The results of this paper might help one to understand the intrinsic energy alteration mechanisms of neuronal synchronization.