Coherence Values Research Articles

Heart to breathe: partial ablation of rostral ventrolateral medulla catecholaminergic neurons mediates disordered breathing in volume overload heart failure rats

Heart to breathe: partial ablation of rostral ventrolateral medulla catecholaminergic neurons mediates disordered breathing in volume overload heart failure rats

Properties of the coherence function between a sound envelope and magnetoencephalogram data in a selective listening study

As a novel method for analyzing the auditory-evoked brain response, we used the coherence function between a sound envelope and brain signal, such as a signal acquired on a magnetoencephalogram (MEG) or an electroencephalogram (EEG), in a selective listening study. In this study, we examined mixed sounds with various mixing ratios and investigated how the coherence value changes according to the ease of hearing. We used two types of mixed sounds: speech mix and music mix. We investigated three types of mixing ratios: easy, normal, and difficult with respect to hearing the target sound. MEG recording was obtained as each mixed sound was heard. We calculated the coherence function between the sound envelope and the MEG data. This is a function of the frequency, and a higher coherence value indicates that both signals have higher correlation at that frequency. We found that the coherence value tends to increase according to the easiness of hearing the target sound. This property might be useful for developing a new-type of hearing aid for selective listening.

Clinical and electrophysiological parameters of alcohol dependence and its comorbidity with affective disorders

To identify characteristics of and possible differences in clinical and electroencephalographic parameters in patients with alcohol dependence with- and without comorbid affective disorders. Ninety-five patients, including 74 with an established diagnosis of alcohol dependence and 21 with alcohol dependence and affective disorders, were examined. Duration of alcohol dependence and affective disorder (years), number of hospitalizations and suicidal attempts were analyzed as anamnestic data. Hamilton's anxiety and depression scale (HDRS), the Alcohol Use Disorders Identification Test (AUDIT), the General clinical impression scale (CGI-s) were used as psychometric tools. The study of bioelectric activity of the brain was carried out using a 16-channel encephalograph. The background electroencephalogram was recorded, the values of absolute spectral power and coherence of theta, alpha and beta rhythms were analyzed. Patients with comorbidity of alcohol dependence and affective disorders have a significantly higher risk of suicidal behavior, a greater frequency of hospitalizations, higher levels of anxiety compared with patients without affective disorders. Electrophysiological data have shown that patients with comorbidity of alcohol dependence and affective disorders have higher values of spectral power of alpha-rhythm in all parts of the cerebral cortex (except for temporal lobes) and beta-rhythm in the occipital cortex, as well as an increase in interhemispheric coherence in all frequency ranges.

QUANTIFICAÇÃO DE MULLITA PROVENIENTE DE RESÍDUOS DE CAULIM DA REGIÃO AMAZÔNICA: USO DO MÉTODO DE RIETVELD

QUANTIFICATION OF MULLITE FROM KAOLIN WASTES FROM THE AMAZON REGION: USE OF THE RIETVELD METHOD. Mullite is used to obtain a refractory material, there are several factors that influence the synthesis process of mullite: the preparation of the mixture, the precipitation and the reaction of SiO2 and Al2O3. For the synthesis of mullite, samples of kaolin processing residues were used as precursor material, because it presents SiO2 and Al2O3 in its composition. This work aimed to identify, by X-ray diffraction, and quantify the mineral phases present in samples of kaolin processing residues from the Amazon region calcined at 1300, 1400 and 1500 ºC, using the Rietveld method. The method allowed the refinement of the complex crystalline structures and was applied to the data supply for quantitative analyses with satisfactory results of good accuracy. The results of the quantification of crystalline and non-crystalline phases (with internal standard) in the samples calcined at 1500 ºC presented approximate values of mullite (62%), cristobalite (32%) and non-crystalline phases (6%), for both samples, indicating that the refinement model applied is optimal. These results obtained from the quantification of the phases by the method of Rietveld are presenting coherent and satisfactory values, in comparison with the theoretical ones by the phase diagram Al2O3 and SiO2

Directional Coherence-Based Scrolling-Text Detection for Frame Rate Up-Conversion

This article proposes a new scrolling-text detection method that uses directional coherence for frame rate up-conversion (FRUC). Most previous methods use either gradient information or motion vector (MV) distribution of the frame for scrolling-text detection. Edges can be generated by non-text components and the number of MVs to determine the scrolling-text decreases in each row of the frame. Thus, they incorrectly detect the non-text regions as scrolling-text and cannot accurately detect the start or end of text scrolling at the frame boundary. The proposed method overcomes these problems using coherence values of edge directions for each pixel and scrolling-text-aware refinement processes. The key idea of the proposed method is to use the directional coherence of edge directions and use texture patterns analysis-based refinement to improve the accuracy of the scrolling-text detection. For refinement processes, the proposed method extracts texture patterns as bit codes. Then, it computes the diversity of the texture patterns around the detected text edges. In addition, the proposed method extracts the representative value of the MV for the detected region to correct the regions falsely detected as the scrolling-text. With these refinement processes, the proposed method can also accurately detect the start or end of text scrolling at the frame boundary. In the experimental results, the proposed method increased the average F1 score to 0.504 (a 131.25% improvement) compared with previous methods. The average computation time per pixel of the proposed method also decreased to $18.571~\mu \text{s}$ (an 80.80% reduction) compared with previous methods.

Neither conflict, no concord: Performing ideology in contemporary Russia

Authors interpret the results achieved by analyzing the content of Russian political parties’ manifestos that managed to enter the State Duma after 2011 and 2016 elections. Our conceptual framework is based on Immanuel Wallerstein’s assumption that only three ideologies—liberalism, conservatism and socialism — were the key ones to 20 th century experience and, hence, that any particular ideology might be reduced to that list. Firstly, we build a matrix of content analysis to analyze texts of officially published political parties’ programs. As a result we could show that values at the core of any program at any stage were hybrid in nature and that there was increase in liberal rhetoric in 2016. Further we interpret the empirical results by applying both classical (M. Seliger) and modern (J. Schwartzmantel) models of ideology. By using Seliger’s conception of ideology we demonstrate that our political parties choose not to defend the coherent value core of their programs in order to fulfill ‘technical’ task of generating sufficient electoral support. Schwartzmantel’s idea that neo-liberalism as a “classical” state-oriented ideology is attacked by a plenty of non-classical, network-organized ideologies nowadays does not fit our reality, because there is no. pronounced opposition between neo-liberal and critical political discourses. Thus, we argue there is no. normative foundation either for conflict or concord among ideological projects and, moreover, that ideological struggle on the Russian political arena has left classical political domain. It requires social sciences to renew its methodological implements for analyzing ideology properly, while philosophy faces with self-description challenge.

Global EEG coherence as a marker for cognition in older adults at risk for dementia.

Quantitative electroencephalography (EEG) provides useful information about neurophysiological health of the aging brain. Current studies investigating EEG coherence and power for specific brain areas and frequency bands have yielded inconsistent results. This study assessed EEG coherence and power indices at rest measured over the whole skull and for a wide frequency range as global EEG markers for cognition in a sample at risk for dementia. Since global markers are more reliable and less error-prone than region- and frequency-specific indices they might help to overcome previous inconsistencies. Global EEG coherence (1-30Hz) and an EEG slowing score were assessed. The EEG slowing score was calculated by low-frequency power (1-8Hz) divided by high-frequency power (9-30Hz). In addition, the prognostic value of the two EEG indices for cognition and cognitive decline was assessed in a 5-year follow-up pilot study. Baseline global coherence correlated positively with cognition at baseline, but not with cognitive decline or with cognition at the 5-year follow-up. The EEG slowing ratio showed no significant association, neither with cognition at baseline or follow-up, nor with cognitive decline over a period of 5years. The results indicate that the resting state global EEG coherence might be a useful and easy to assess electrophysiological correlate for neurocognitive health in older adults at risk for dementia. Because of the small statistical power for the follow-up analyses, the prognostic value of global coherence could not be determined in the present study. Future studies should assess its prognostic value with larger sample sizes.

Assessment of text coherence using an ontology‐based relatedness measurement method

AbstractThis paper proposes a novel method for assessing text coherence. Central to this approach is an ontology‐based representation of text, which captures the level of relatedness between consecutive sentences via ontologies. Our method encompasses annotating text using ontological concepts and assessing text coherence based on relatedness measurement among these concepts. The ontology‐based relatedness measurement method used in this study considers various types of relationships in ontologies and derived relationships via an inference engine for computing relatedness. We hypothesized that rich variety of relationships and inferred facts in ontologies would improve the success of text coherence assessment. Our results demonstrate that the use of ontologies yields to coherence values that have a higher correlation with human ratings.

Benign Rolandic epilepsy: widespread increases in connectivity in a focal epilepsy syndrome.

Benign Rolandic epilepsy (benign epilepsy with centrotemporal spikes; recently renamed self-limited epilepsy with centrotemporal spikes) is associated with widespread deficits in cognition and behavior, suggesting abnormalities in networks that extend beyond the centrotemporal region. To assess functional connectivity in children with benign Rolandic epilepsy, we assessed EEG spectral power and coherence during awake and sleep records in 27 children with centrotemporal spikes. Coherence represents the consistency of the phase difference between two EEG signals when compared over time and serves as a measure of synchronization between two EEG signals based mainly on phase consistency. Epochs of EEG with and without centrotemporal spikes were compared during both waking and sleep. During the spike epochs, there was an increase in spectral power at all frequencies, although statistical significance was seen primarily in the delta, theta and alpha bandwidths. This increase in absolute power was seen at all electrode sites and was similar in left and right-sided electrodes. During centrotemporal spikes, there were significant changes in coherence compared to the EEG segments without spikes. In the theta, alpha and beta bandwidths, there were significant increases in coherence. The increases in coherences were widespread and bilateral, and involved electrode pairs outside the central and temporal regions. To determine if there was a relationship between location of the spikes and coherence values, right-sided, left-sided and bilateral centrotemporal spikes were compared. There was no relationship between location of the centrotemporal spikes and power or coherence values. These findings indicate that benign Rolandic epilepsy results in generalized changes in spectral power and connectivity and raises the suggestion that from a functional standpoint, benign Rolandic epilepsy resembles a generalized rather than focal seizure disorder.

Polarization dynamics in a resonant optical medium with initial coherence between degenerate states

<p style='text-indent:20px;'>We investigate the polarization switching phenomenon for a one-soliton solution to the <inline-formula><tex-math id="M1">\begin{document}$ \Lambda $\end{document}</tex-math></inline-formula>-configuration Maxwell-Bloch equations in the case of initial coherence in the material, corresponding to the forbidden transition between the two lower energy levels. We find two polarization states that are stationary. They are not the purely right- and left-circularly polarized solitons, as in the case of zero initial coherence, but rather two mixed, elliptically polarized, states. These polarization states, of which only one is asymptotically stable, depend on both the initial population levels of the lower states and the coherence value. We also find the existence of superluminal soliton propagation, but through numerical simulations show this solution to be unstable, and therefore likely not realizable physically.

Quality of practice in supported accommodation services for people with intellectual disabilities: What matters at the organisational level

ABSTRACT Background: Organisational and service level factors are identified as influencing the implementation of Active Support. The aim was to explore differences in organisational leadership and structures to identify potential relationships between these factors and the quality of Active Support in supported accommodation services. Method: Fourteen organisations participated in this mixed methods study, which generated data from interviews with senior leaders, document reviews and observations of the quality of Active Support. Results: Qualitative analyses revealed three conceptual categories: senior leaders in organisations where at least 71% of services delivered good Active Support prioritised practice; understood Active Support; and strongly supported practice leadership. In these organisations practice leadership was structured close to everyday service delivery, and as part of frontline management. Conclusions: Patterns of coherent values, priorities and actions about practice demonstrated by senior leaders were associated with successful implementation of Active Support, rather than documented values in organisational policy or procedures.

Change in left inferior frontal connectivity with less unexpected harmonic cadence by musical expertise.

In terms of harmonic expectancy, compared to an expected dominant-to-tonic and an unexpected dominant-to-supertonic, a dominant-to-submediant is a less unexpected cadence, the perception of which may depend on the subject’s musical expertise. The present study investigated how aforementioned 3 different cadences are processed in the networks of bilateral inferior frontal gyri (IFGs) and superior temporal gyri (STGs) with magnetoencephalography. We compared the correct rate and brain connectivity in 9 music-majors (mean age, 23.5 ± 3.4 years; musical training period, 18.7 ± 4.0 years) and 10 non-music-majors (mean age, 25.2 ± 2.6 years; musical training period, 4.2 ± 1.5 years). For the brain connectivity, we computed the summation of partial directed coherence (PDC) values for inflows/outflows to/from each area (sPDCi/sPDCo) in bilateral IFGs and STGs. In the behavioral responses, music-majors were better than non-music-majors for all 3 cadences (p < 0.05). However, sPDCi/sPDCo was prominent only for the dominant-to-submediant in the left IFG. The sPDCi was more strongly enhanced in music-majors than in non-music-majors (p = 0.002, Bonferroni corrected), while the sPDCo was vice versa (p = 0.005, Bonferroni corrected). Our data show that music-majors, with higher musical expertise, are better in identifying a less unexpected cadence than non-music-majors, with connectivity changes centered on the left IFG.

Effects of physical training on brain functional connectivity of methamphetamine dependencies as assessed using functional near-infrared spectroscopy

ObjectiveThis study aims to assess the effects of physical training based on the functional near-infrared spectroscopy (fNIRS) and heart rate signals. MethodsThe oxygenated hemoglobin concentration (Delta [HbO2]) signals were recorded from the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left motor cortex (LMC) and right motor cortex (RMC) of 23 subjects with methamphetamine (METH) dependencies at resting, spinning training and strength training states. The wavelet phase coherence (WPCO) values were calculated in four frequency intervals: I, 0.6–2; II, 0.145–0.6; III, 0.052–0.145; and IV, 0.021–0.052 Hz. During the spinning training and strength training states, heart rate signals were recorded at 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 min, respectively. ResultsAfter physical training, the brain regions of LPFC, RPFC and LMC showed different degrees of activation in the subjects with METH dependencies (p < 0.05). The WPCO values between the brain regions significantly altered after spinning training and strength training (p < 0.05) in frequency intervals I, II, III and IV. ConclusionsThe altered WPCO values indicated physical training could affect brain functional connectivity (FC) to a certain extent in the subjects with METH dependencies. These findings provide a method for the assessment of the effects of physical training in FC and will contribute to the development of drug rehabilitation methods in subjects with METH dependencies.

The problem of quality assessing for the methods of coherence maps calculation in InSAR remote sensing of the Earth data processing

Interferometric coherence is an important indicator of the quality of interferograms obtained by synthetic aperture interferometric radars (InSAR), because the areas with low coherence are not suitable for interferometric data processing. The coherence value is used as a parameter for adaptive phase noise suppression algorithms. It can also be used for surface classification tasks. The paper investigates the problem of the coherence estimate reducing under the influence of the topographic phase slope and considers ways to reduce the impact of the slope on the estimate value. The paper presents a comparative efficiency analysis of four methods for coherence maps calculation used for the phase noise suppression on the interferograms by a spectral adaptive filter in interferometric data processing for the Earth’s remote sensing space radar ALOS PALSAR

Theology of the Rule of Law

This article draws conceptual, genealogical, and empirical parallels between religion and the rule of law. It presents two related arguments. First, despite the rule of law’s religious roots, the attempts of modern states since the nineteenth century to regulate and stymie religious power are a key part of the rule of law’s history. Second, as a systematically developed theory of internally coherent values about a higher power, the rule of law offers an alternative to theology. Political elites, scholars, and activists invoke this theology of the rule of law as clerics would a religious discourse, for their own salvation or for the salvation of the poor and marginalized.

QEEG correlates of cognitive processing speed in children and adolescents with traumatic brain injuries

Both quantitative electroencephalography (qEEG) and cognitive measures have been used to understand the underlying brain changes that occur in individuals after experiencing a traumatic brain injury, however, research exploring the relationship between qEEG patterns and cognitive test performance is scarcely studied in school-aged populations. The purpose of the present study was to explore first, the neuropsychological and academic deficits in young individuals with TBI; and second, the underlying relationship between qEEG patterns and cognitive test performance. Analyses included 21 school-aged participants whom have experienced a recent TBI and 15 school-aged participants whom have never experienced a TBI. Mean subtest and composite scores were compared and regression analyses were used to determine whether alpha band and beta band qEEG coherence values predicted processing speed measures. Results suggest that young individuals who experienced a recent TBI exhibit general deficits in cognition and academic skills beyond what would be expected in the general population. Further, beta band coherence with the frontal brain regions significantly predicted processing speed scores, providing evidence of a relationship between qEEG patterns and processing speed. This outlines a relatively inexpensive method for utilizing neural connectivity to verify cognitive deficits for school-aged individuals with a recent TBI.

Effects of task dynamics on coordination of the hand muscles and their adaptation to targeted muscle assistance

Dynamic characteristics of a manual task can affect the control of hand muscles due to the difference in biomechanical/physiological characteristics of the muscles and sensory afferents in the hand. We aimed to examine the effects of task dynamics on the coordination of hand muscles, and on the motor adaptation to external assistance. Twenty-four healthy subjects performed one of the two types of a finger extension task, isometric dorsal fingertip force production (static) or isokinetic finger extension (dynamic). Subjects performed the tasks voluntarily without assistance, or with a biomimetic exotendon providing targeted assistance to their extrinsic muscles. In unassisted conditions, significant between-task differences were found in the coordination of the extrinsic and intrinsic hand muscles, while the extrinsic muscle activities were similar between the tasks. Under assistance, while the muscle coordination remained relatively unaffected during the dynamic task, significant changes in the coordination between the extrinsic and intrinsic muscles were observed during the static task. Intermuscular coherence values generally decreased during the static task under assistance, but increased during the dynamic task (all p-values < 0.01). Additionally, a significant change in the task dynamics was induced by assistance only during static task. Our study showed that task type significantly affect coordination between the extrinsic and intrinsic hand muscles. During the static task, a lack of sensory information from musculotendons and joint receptors (more sensitive to changes in length/force) is postulated to have resulted in a neural decoupling between muscles and a consequent isolated modulation of the intrinsic muscle activity.

Field of coherence of GPS-measured earth tremors

A new method for investigating the coherence field of the noise component of high-frequency GPS time series is proposed. The method is applied to the main territory of the USA, which is characterized by a dense network of GPS stations. The data are presented in steps of 5 min from February 28, 2013, until June 29, 2019, on the Nevada Geodetic Laboratory Web site. The proposed method estimates the spatial distribution of the mean values of multiple coherence, calculated within nodes of a regular grid, between GPS coordinates of a given number of nearest operable stations and the periods at which the maximum values of coherence are reached. The two-dimensional probability density of the positions of places where the coherence maximum is most often realized is estimated. These estimates can be obtained for the entire history of observations and also in a sliding time window of a given length, which makes it possible to trace the dynamics of changes in time in the coherence field of the earth’s tremor. The entropy of the two-dimensional probability density of places of concentration of maximum values of coherence allows us to distinguish seasonal changes in the structure of the coherence field of GPS noise. To study the temporal dynamics, we use the auxiliary time series of changes in the maximum multiple coherence at 50 reference points located throughout the study area. The study of the coherence properties of this auxiliary 50-dimensional time series (“secondary coherence”) in a 180-day sliding time window highlighted a series of synchronization bursts of earth’s surface tremors.

Validating the Model of a No-Till Coulter Assembly Equipped with a Magnetorheological Damping System

Variability in soil conditions has a significant influence on the performance of a no-till seeder in terms of an inconsistency in the depth of seeding. This occurs due to the inappropriate dynamic responses of the coulter to the variable soil conditions. In this work, the dynamics of a coulter assembly, designed with a magnetorheological (MR) damping system, were simulated, in terms of vertical movement and ground impact. The developed model used measured inputs from previously performed experiments, i.e., surface profiles and vertical forces. Subsequently, the actual coulter was reassembled with an MR damping system. Multiple sensors were attached to the developed coulter in order to capture its motion behavior together with the profiles, which were followed by the packer wheel. With the aim to validate the correctness of the simulation model, the simulation outputs, i.e., pitch angles and damper forces, were compared to the measured ones. The comparison was based on the root-mean-squared error (RMSE) in percentage, the root-mean-squared deviation (RMSD), and the correlation coefficient. The average value of the RMSE for the pitch angle, for all currents applied on the MR damper, was below 10% and 8% for the speeds of 10 km h−1 and 12 km h−1, respectively. For the damper force, these figures were 15% and 13%. The RMSD was below 0.5 deg and 1.3 N for the pitch angle and the damper force, respectively. The correlation coefficient for all datasets was above 0.95 and 0.7 for the pitch angle and the damper force, respectively. Since the damper force indicated a comparatively lower correlation in the time domain, its frequency domain and coherence were investigated. The coherence value was above 0.9 for all datasets.

Digital holography free of 2π ambiguity, using coherence modulation.

In this Letter, a quantitative measurement method with an extended axial range in low-coherence light digital holography is presented. Based on the characteristics of the light source, the degree of coherence and phase values are obtained. Because the degree of coherence is modulated with respect to the optical path difference, it can be used to remove the 2π ambiguity of the phase, without the use of numerical or dual-wavelength methods. The mathematical procedures from three phase-shifting holograms are numerically described. From experimental results, the accurate measurements of a sample with high step are presented to confirm the effectiveness.