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Transfer entropy

Reiji Suzuki, Shiho Matsubayashi, Fumiyuki Saito, Tatsuyoshi Murate, Tomohisa Masuda, Koichi Yamamoto, Ryosuke Kojima, Kazuhiro Nakadai, Hiroshi G Okuno
Acoustic interactions are important for understanding intra- and interspecific communication in songbird communities from the viewpoint of soundscape ecology. It has been suggested that birds may divide up sound space to increase communication efficiency in such a manner that they tend to avoid overlap with other birds when they sing. We are interested in clarifying the dynamics underlying the process as an example of complex systems based on short-term behavioral plasticity. However, it is very problematic to manually collect spatiotemporal patterns of acoustic events in natural habitats using data derived from a standard single-channel recording of several species singing simultaneously...
January 2018: Ecology and Evolution
Yuqing Qiu, Laura Lupi, Valeria Molinero
Graphitic surfaces are the main component of soot, a major constituent of atmospheric aerosols. Experiments indicate that soots of different origins display a wide range of abilities to heterogeneously nucleate ice. The ability of pure graphite to nucleate ice in experiments, however, seems to be almost negligible. Nevertheless, molecular simulations with the monatomic water model mW predict that pure graphite nucleates ice. According to Classical Nucleation Theory, the ability of a surface to nucleate ice is controlled by the binding free energy between ice immersed in liquid water and the surface...
January 3, 2018: Journal of Physical Chemistry. B
M S Sannaikar, Laxmi S Inamdar, G H Pujar, M N Wari, Nafisa H Balasinor, S R Inamdar
Polyethylene glycol (PEG) surface modified biocompatible InP/ZnS quantum dots (QDs) act as a potential alternative for conventional carcinogenic cadmium-based quantum dots for in vivo and in vitro studies. Comprehensively, we studied the interaction between a model protein bovine serum albumin (BSA) and PEGylated toxic free InP/ZnS QDs using various spectroscopic tools such as absorption, fluorescence quenching, time resolved and synchronous fluorescence spectroscopic measurements. These studies principally show that tryptophan (Trp) residues of BSA have preferable binding affinity towards PEG-InP/ZnS QDs surface and a blue shift in Trp fluorescence emission is a signature of conformational changes in its hydrophobic microenvironment...
December 28, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Zafeirios Fountas, Murray Shanahan
Although brain oscillations involving the basal ganglia (BG) have been the target of extensive research, the main focus lies disproportionally on oscillations generated within the BG circuit rather than other sources, such as cortical areas. We remedy this here by investigating the influence of various cortical frequency bands on the intrinsic effective connectivity of the BG, as well as the role of the latter in regulating cortical behaviour. To do this, we construct a detailed neural model of the complete BG circuit based on fine-tuned spiking neurons, with both electrical and chemical synapses as well as short-term plasticity between structures...
2017: PloS One
Kaizhou Chen, Yongtao Wang, Jia Yao, Haoran Li
The degree of proton transfer and thermodynamic parameters of six acetate-based protic ionic liquids (PILs) were measured using nuclear magnetic resonance (NMR) spectroscopy and calculated by van't Hoff analytical method, respectively. The degree of proton transfer of these PILs at 298 K spread over a large range, which is from 39.6% (1-methylpyrrolidinium acetate, [MpyrH][AcO]) to 94.4% (1-butylimidazolium acetate, [BuimH][AcO]). The calculated standard enthalpy change of the reaction (∆_r H_m^θ) is from -23...
December 12, 2017: Journal of Physical Chemistry. B
Yuta Saegusa, Tomoya Ishizuka, Yoshihito Shiota, Kazunari Yoshizawa, Takahiko Kojima
We report herein NH tautomerism of a freebase derivative of a quadruply fused porphyrin (H2QFP-Mes, 3), which has one mesityl group at one of the β-positions of the non-fused pyrroles to lower the structural symmetry, allowing us to observe the NH tautomerism with 1H NMR spectroscopy. Compound 3 was revealed to have the two inner NH protons on the two non-fused pyrroles and the NH tautomerism of 3 was evidenced by variable-temperature (VT) 1H NMR experiments in various deuterated solvents. The VT-NMR studies revealed that the activation barrier for the NH tautomerism of 3 was larger than that of tetraphenylporphyrin...
December 10, 2017: Journal of Physical Chemistry. B
Yuan Wang, Shan Bao, Wenjun Du, Zhirui Ye, James R Sayer
INTRODUCTION: Visual attention to the driving environment is of great importance for road safety. Eye glance behavior has been used as an indicator of distracted driving. This study examined and quantified drivers' glance patterns and features during distracted driving. METHOD: Data from an existing naturalistic driving study were used. Entropy rate was calculated and used to assess the randomness associated with drivers' scanning patterns. A glance-transition proportion matrix was defined to quantity visual search patterns transitioning among four main eye glance locations while driving (i...
December 2017: Journal of Safety Research
Hao Huang, Haihua Xu, Ying Hu, Gang Zhou
Goodness of pronunciation (GOP) is the most widely used method for automatic mispronunciation detection. In this paper, a transfer learning approach to GOP based mispronunciation detection when applying maximum F1-score criterion (MFC) training to deep neural network (DNN)-hidden Markov model based acoustic models is proposed. Rather than train the whole network using MFC, a DNN is used, whose hidden layers are borrowed from native speech recognition with only the softmax layer trained according to the MFC objective function...
November 2017: Journal of the Acoustical Society of America
Nicole DeGregorio, Srinivasan Sesha Iyengar
We present two sampling measures to gauge critical regions of potential energy surfaces. These sampling measures employ (a) the instantaneous quantum wavepacket density, an approximation to the (b) potential surface, its (c) gradients, and (d) a Shannon information theory based expression that estimates the local entropy associated with the quantum wavepacket. These four criteria together enable a directed sampling of potential surfaces that appears to correctly describe the local oscillation frequencies, or the local Nyquist frequency, of a potential surface...
November 28, 2017: Journal of Chemical Theory and Computation
Evangelos Paraskevopoulos, Nikolas Chalas, Panagiotis Bamidis
Statistical learning is a cognitive process of great importance for the detection and representation of environmental regularities. Complex cognitive processes such as statistical learning usually emerge as a result of the activation of widespread cortical areas functioning in dynamic networks. The present study investigated the cortical large-scale network supporting statistical learning of tone sequences in humans. The reorganization of this network related to musical expertise was assessed via a cross-sectional comparison of a group of musicians to a group of non-musicians...
November 24, 2017: Scientific Reports
Immo Weber, Esther Florin, Michael von Papen, Lars Timmermann
Transfer entropy (TE) provides a generalized and model-free framework to study Wiener-Granger causality between brain regions. Because of its nonparametric character, TE can infer directed information flow also from nonlinear systems. Despite its increasing number of applications in neuroscience, not much is known regarding the influence of common electrophysiological preprocessing on its estimation. We test the influence of filtering and downsampling on a recently proposed nearest neighborhood based TE estimator...
2017: PloS One
Sourabh Lahiri, Philippe Nghe, Sander J Tans, Martin Luc Rosinberg, David Lacoste
Inferring the directionality of interactions between cellular processes is a major challenge in systems biology. Time-lagged correlations allow to discriminate between alternative models, but they still rely on assumed underlying interactions. Here, we use the transfer entropy (TE), an information-theoretic quantity that quantifies the directional influence between fluctuating variables in a model-free way. We present a theoretical approach to compute the transfer entropy, even when the noise has an extrinsic component or in the presence of feedback...
2017: PloS One
Kazuo Takatsuka
In light of the rapid progress of ultrafast chemical dynamics driven by the pulse lasers having width as short as several tens of attoseconds, we herein develop a theory of nonadiabatic electron wavepacket dynamics in condensed phases, with which to directly track the dynamics of electronic-state mixing such as electron transfer in liquid solvents. Toward this goal, we combine a theory of path-branching representation for nonadiabatic electron wavepacket dynamics in vacuum {a mixed quantum-classical representation, Yonehara and Takatsuka [J...
November 7, 2017: Journal of Chemical Physics
Aswathy Joseph, Vibin Ipe Thomas, Gaweł Żyła, Padmanabhan Sridharan Alapat, Suresh Mathew
A comprehensive study on the structure, nature of interaction and properties of six ionic pairs of 1-butylpyridinium and 1-butyl-4-methylpyridinium cations in combination with tetrafluoroborate (BF4-), chloride (Cl-) and bromide (Br-) anions have been carried out using Density Functional Theory (DFT). The anion-cation interaction energy (ΔEint), theoretical band gap, molecular orbital energy-order, DFT-based chemical activity descriptors: chemical potential (μ), chemical hardness (η) and electrophilicity index (ω) and distribution of density of states (DOS) of these ion-pairs were investigated...
November 7, 2017: Journal of Physical Chemistry. A
Shinnosuke Nakayama, Manuel Ruiz Marín, Maximo Camacho, Maurizio Porfiri
In humans, emergence of leaders and followers is key to group performance, but little is known about the whys and hows of leadership. A particularly elusive question entails behavioral plasticity in leadership across social contexts. Addressing this question requires to eliminate social feedback between focal individuals and their partners in experiments that could illuminate the spontaneous emergence of social roles. We investigated plasticity in leader-follower roles in cooperation, where members choose the task toward a shared goal, and coordination, where members adjust their actions in real time based on social responsiveness...
November 6, 2017: Scientific Reports
Benjamin Schleicher, Robert Niemann, Stefan Schwabe, Ruben Hühne, Ludwig Schultz, Kornelius Nielsch, Sebastian Fähler
Tuning functional properties of thin caloric films by mechanical stress is currently of high interest. In particular, a controllable magnetisation or transition temperature is desired for improved usability in magnetocaloric devices. Here, we present results of epitaxial magnetocaloric Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMN-PT) substrates. Utilizing X-ray diffraction measurements, we demonstrate that the strain induced in the substrate by application of an electric field can be transferred to the thin film, resulting in a change of the lattice parameters...
October 31, 2017: Scientific Reports
Dheeraj Rathee, Hubert Cecotti, Girijesh Prasad
The level of conscious experience can be effectively and reversibly altered by the administration of sedative agents. Several studies attempted to explore the variations in frontal-parietal network during propofol-induced sedation. However, contradictory outcomes warrant further investigations. In this study, we implemented the Neural Gas algorithm-based delay symbolic transfer entropy (NG-dSTE) for investigation of frontal-parietal-occipital (F-P-O) network using scalp EEG signals recorded during altered levels of consciousness...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Calvin K Young, Ming Ruan, Neil McNaughton
Algorithms for estimating directed connectivity have become indispensable to further understand the neurodynamics between functionally coupled brain areas. The evaluation of directed connectivity on the propagation of brain activity has largely been based on simulated data or toy models, where various hidden properties of neurophysiological data may not be fully recapitulated. In this study, directionality was unequivocally manipulated in the freely moving rat in a unique dataset, where normal oscillatory interactions between the supramammillary nucleus (SuM) and hippocampus (HPC) were attenuated by temporary medial septal (MS) inactivation, and replaced by electrical stimulation of the fornix to evaluate the performance of several directed connectivity assessment methods...
2017: Frontiers in Systems Neuroscience
Vito Paolo Pastore, Aleksandar Godjoski, Sergio Martinoia, Paolo Massobrio
We implemented an automated and efficient open-source software for the analysis of multi-site neuronal spike signals. The software package, named SPICODYN, has been developed as a standalone windows GUI application, using C# programming language with Microsoft Visual Studio based on .NET framework 4.5 development environment. Accepted input data formats are HDF5, level 5 MAT and text files, containing recorded or generated time series spike signals data. SPICODYN processes such electrophysiological signals focusing on: spiking and bursting dynamics and functional-effective connectivity analysis...
October 7, 2017: Neuroinformatics
Maristella Lucchini, Nicolò Pini, William P Fifer, Nina Burtchen, Maria G Signorini
Sleep is a central activity in human adults and characterizes most of the newborn infant life. During sleep, autonomic control acts to modulate heart rate variability (HRV) and respiration. Mechanisms underlying cardiorespiratory interactions in different sleep states have been studied but are not yet fully understood. Signal processing approaches have focused on cardiorespiratory analysis to elucidate this co-regulation. This manuscript proposes to analyze heart rate (HR), respiratory variability and their interrelationship in newborn infants to characterize cardiorespiratory interactions in different sleep states (active vs...
May 2017: Entropy
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