Rest State Research Articles

Problem of the Boundary Control of Oscillations of a Sample of a Layered Two-Phase Composite Material

We consider the problem of the boundary control of one-dimensional oscillations of an effective (averaged) medium corresponding to a two-phase medium consisting of periodically alternating layers of elastic and viscoelastic materials with long-term memory or various viscoelastic materials with Kelvin–Voigt friction and long-term memory. The averaged model is described by a boundary value problem for an integrodifferential equation. It is shown that for this model, it is impossible to bring oscillations to a state of rest in finite time (in contrast to the equation of string oscillations) by a force acting at one end of the band. A hypothesis is formulated on the possibility of bringing the specified object to a state of rest with the help of force effects distributed along the entire length of the object.

Alpha-Theta Correlations during the Different States of the Brain for a Designed Cognitive Task

Brain oscillations vary due to neurological activities that play an important role in designing a cognitive task. In the proposed study, 27 subjects experimented with different cognitive activities (rest, meditation, and arithmetic) and their alpha and theta bands of frequencies were analyzed. BIOPAC-MP-160 has performed the data acquisition and further processing of the acquired dataset was implemented in EEGLAB. The results illustrated that the cross-frequency correlation (alpha: theta: 1:2) between alpha and theta waves has been enhanced during effortful cognition (arithmetic state). The alpha-theta cross-frequencies were observed to be maximum in the arithmetic state, while it remains low in both the resting and meditation states. Maximum episodes of the cross-frequency correlations occurred when the alpha band of frequencies lies between 9-12 Hz. The study also reveals that maximum alpha-theta cross-frequency (40.74%) was found at the electrode positions Af3 and Af4. The comparisons based on event-related potentials (ERPs) and power spectral densities (PSDs) have shown that the meditation state is more sluggish than the arithmetic and rest states.

ВЗАИМОСВЯЗЬ ОРТОДОНТИЧЕСКИХ КОНСТРУКЦИЙ ДЛЯ ВЫДВИЖЕНИЯ НИЖНЕЙ ЧЕЛЮСТИ И ПОСТУРАЛЬНОГО БАЛАНСА

One of the topical issues of dentistry is the assessment of the functional state of the dental apparatus and the features of an individual treatment plan for various categories of dental patients.The aim of the work is to register the postural balance of patients for an objective assessment of the state of the postural system as a whole and its influence on the dental system. The method of work consists in the analysis of postural balance with the application of stabilometry in patients with physiological occlusion and distal occlusion of the dentition when using devices for extending the lower jaw. The contingent of test subjects was 31 children 8-12 years old, including 10 people with physiological occlusion (control group) and 21 children with distal occlusion (DO). In addition to the main diagnostic methods in orthodontics, all the examined children underwent a stabilometric examination. In addition to the main analysis, children were examined with tightly closed dental raws and in a state of physiological rest, as well as with and without orthodontic structures.The main results of the work showed that in patients with orthognathic bite, tight closure of the dental raws does not cause significant stabilometric changes, whereas in children with distal occlusion with tight closure of the dental raws is significant the postural balance deteriorates significantly. When treating children with the help of orthodontic constructions of functional action, there is a significant improvement in postural balance. At the same time, the parameters of the statokinesiogram in the group of patients treated with individually manufactured devices improve much more than in the group of children treated with standard manufactured structures.

Analysis of Undamped Free Vibration Parameters using GeoGebra

Through this article, a teaching methodology will be designed using a simulation in Geo Gebra, arose due to the need to contribute to the achievement of significant learning in the field of Mechanical Predictive Maintenance of the Industrial Maintenance Career at the Technological University of Xicotepec de Juárez, In this research, a teaching methodology was designed using a simulation in Geo Gebra since the university students could not understand the concepts about simple harmonic motion (MAS) as it is also known as undamped free vibration. Vibrations occur in systems that try to return to their state of rest or equilibrium when they are disturbed, or move away from their equilibrium state. It is about presenting how a simple harmonic motion problem was solved, highlighting the physical characteristics of the phenomenon. The current educational format has led teachers to use GeoGebra to analyze the behavior of some physical variables, proposing to students to interact with a simulation. With this it can be verified that, in relation to a simulation, it helps to facilitate the understanding of the concepts

Inner speech as a brain mechanism for preconditioning creativity process

The current domain of creativity studies is characterized by a high diversity of psychological and neuroscience techniques and methods researchers use. However, the role of verbal processes, especially inner speech, remains underrepresented in this area. Existing studies point to the heterogeneity of inner speech brain mechanisms involved in creative thinking. While consciously controlled verbalized thoughts are associated with the activity of task-dependent brain networks (TPN), especially lateral-frontoparietal network (L-FPN), non-voluntary, mind-wandering thoughts are supposed to correlate with default-mode networks (DMN) activity. While DMN activity leads to an increased number of creative ideas, L-FPN activity results in fewer ideas but increased idea originality. From this point, rest state and state of getting prepared (preconditioning) to task completion, when both mind-wandering and control thoughts occur, are of specific interest. In our study, 49 volunteers completed divergent thinking tasks with rest state and preconditioning state preceded. We later divided all participants into two groups – with low and high creativity levels based on their performance during divergent tasks. EEG was recorded during rest state and preconditioning state and analyzed based on power spectrum and sLORETA data. Our results show an essential role of preconditioning alpha-2 EEG subband in creative thinking performance. The originality of the task solution correlates with the activity of L-FPN structures, while DMN activity does not differ significantly between the two groups. Disclosure statement No potential conflict of interest was reported by the authors.

The influence of weather and climate parameters on the winter rapeseed productivity

Purpose. To study the influence of hydrothermal resources on the productivity of winter rapeseed. Methods. Field (conducting phenological observations and records), measuring and weighting (for recording productivity and yield), mathematical, statistical and correlational analysis (objective assessment of the obtained experimental data). Results. Varieties of winter rapeseed of different ecological and geographical origin were taken as research material. For the analysis, the conditions of the full vegetation period, “seedlings-termination of vegetation”, “restoration of vegetation-beginning of ripening” and “flowering-beginning of ripening” were chosen as the most critical ones. The importance of using the hydrothermal coefficient as an integral indicator in determining the cumulative effect of climatic factors on the yield characteristics of winter rapeseed plants has been proven. It has been established that the following factors have the greatest influence on the formation of rapeseed productivity: duration of the growing season, the sum of active temperatures and the sum of precipitation under a above +10°C temperature regime, especially during the “flowering-beginning of ripening” period. Conclusions. Hydrothermal conditions affect the productivity of winter rapeseed plants. During the entire vegetation period, the following factors had the greatest positive influence: the length of the vegetation period (in particular, when tfact >0o to +5oC and >+10oC), the sum of temperatures tfact >0o to +5oC, the amount of precipitation. From the beginning of germination to the entry into a state of rest and after the resumption of vegetation in the spring, the following factors have the strongest effect on plants: duration of the vegetation period at tfact >0o to +5oC and >+10oC, the availability of moisture at temperatures from 0o to +10oC. During the flowering-ripening period, the length of the growing season had a positive effect, in particular at air temperature >+10°C against the background of a fairly high sum of active temperatures. The yield of winter rapeseed depends on many abiotic factors, which always provide optimal conditions for the sufficient plant development in autumn and spring, but can negatively affect the flowering of plants, and, accordingly, reduce their productivity.

Pupil size reflects activation of subcortical ascending arousal system nuclei during rest.

Neuromodulatory nuclei that are part of the ascending arousal system (AAS) play a crucial role in regulating cortical state and optimizing task performance. Pupil diameter, under constant luminance conditions, is increasingly used as an index of activity of these AAS nuclei. Indeed, task-based functional imaging studies in humans have begun to provide evidence of stimulus-driven pupil-AAS coupling. However, whether there is such a tight pupil-AAS coupling during rest is not clear. To address this question, we examined simultaneously acquired resting-state fMRI and pupil-size data from 74 participants, focusing on six AAS nuclei: the locus coeruleus, ventral tegmental area, substantia nigra, dorsal and median raphe nuclei, and cholinergic basal forebrain. Activation in all six AAS nuclei was optimally correlated with pupil size at 0-2 s lags, suggesting that spontaneous pupil changes were almost immediately followed by corresponding BOLD-signal changes in the AAS. These results suggest that spontaneous changes in pupil size that occur during states of rest can be used as a noninvasive general index of activity in AAS nuclei. Importantly, the nature of pupil-AAS coupling during rest appears to be vastly different from the relatively slow canonical hemodynamic response function that has been used to characterize task-related pupil-AAS coupling.

Features of winter pea seeds germination under the action of growth regulators

Physiological features of pea seed germination under treatment with exogenous growth regulators based on biologically active substances were studied. Purpose. To investigate the influence of complex growth and development stimulators containing phytohormones and their analogs, Biosil and Gulliver Stimul, on the peculiarities of the seed germination processes and formation of the winter pea seedlings of the Moroz NS variety. Methods. Laboratory, measuring, weighing, quantitative, statistical. Results. The influence of aqueous solutions of growth regulators Biosil and Gulliver Stimul on the germination processes of winter pea seeds was analyzed. During research, it was established that the use of growth regulators contributes to the faster exit of seeds from the state of rest, which is illustrated by the active dynamics of germination. Treatment of winter pea seeds with growth regulators leads to an increase in germination energy by 10-12% and laboratory germination by 6-8% compared to the control. It was noted that the indicators of seed germination were sufficiently high in all samples, including control. The soaking in growth regulators solutions contributes to the 10-16 mg bigger swelling of seeds than in the control; better utilization of reserve compounds, and 38- 50 mg seed weight loss during germination. Phytohormones which are part of the preparations induced an increase in the development of the vegetative organs of pea seedlings, which was expressed in a rapid increase in the length of the shoot and root in experimental variants. The growth of the linear dimensions of the aboveground and underground parts of the seedlings was accompanied by the increase in the mass of raw material. Conclusions. Application of the Biosil and Gulliver Stimul composite plant growth regulators affects the processes of germination and the initial stages of growth of winter pea plants. Treatment of winter pea seeds with these preparations helps to improve seed germination and increase germination energy. The linear dimensions and mass of the raw matter of the roots and shoots of pea seedlings enlarged due to the influence of growth regulators. The maximum length of the root and shoot was observed under the use of Gulliver Stimul preparation

Optimization of the force mode of range change in an articulated boom system with a geared sector at a fixed mode of crane rotation

Variational calculus methods were used to optimize the boom system's flight change mode. For this, a variational problem is set, which includes the differential equations of motion of the jib system, the optimization criterion, and the boundary conditions of the movement when the departure and rotation of the crane are changed. The root-mean-square value of the drive torque of the flight change mechanism during the start-up process, which is an integral function, was chosen as the criterion for optimizing the movement mode of the boom system. The kinematic characteristics of the mechanism for changing the departure of the boom system from the state of rest to reaching the steady speed of the load, at the steady angular speed of the turning mechanism, were chosen as boundary conditions. Such boundary conditions eliminate fluctuations of the load on the flexible suspension after the end of the start-up process when the departure is changed
 As a result of the numerical solution of the given variational problem, graphical dependencies of the optimal kinematic, power and energy characteristics in the process of starting the flight change mechanism, with a fixed mode of rotation of the crane, were constructed. The obtained optimal mode of movement of the departure change mechanism eliminates load fluctuations on the flexible suspension and minimizes dynamic loads.

Fiscal Federalism and Socioeconomic Development in Nigeria

This paper examines how fiscal federalism had enhanced socioeconomic development in Nigeria. Nigeria has 36 states with political autonomy but depend on the federal government for economic survival since all productive activities belong to the federal government. Our analysis and discussion show that states with high production and revenue generation capacities were able to reduced poverty, create more jobs and improve literacy and human capital in spite of the federal government using most of their revenue to service states with less revenue generation capacity. The paper also reveals that almost all the states with very low production and revenue generation capacities have very high poverty level, unemployment and illiteracy level. Lagos, Rivers, Oyo and Ogun states were found to have generated more revenue than the rest states of the federation hence achieved higher level of economic development or socio-economic outcomes than other states. This implies that if the states are allowed to produce based on the available resources they have and pay tax to the federal government, the states will achieve higher level of development than what they have now. Based on these findings, the paper recommends the scraping of the present principles for revenue sharing and the enthronement of the derivation principle in which the federating units produce and pay tax to the central government as measures toward achieving sustainable development in Nigeria

Increased neurocardiological interplay after mindfulness meditation: a brain oscillation-based approach.

Brain oscillations facilitate interaction within the brain network and between the brain and heart activities, and the alpha wave, as a prominent brain oscillation, plays a major role in these coherent activities. We hypothesize that mindfully breathing can make the brain and heart activities more coherent in terms of increased connectivity between the electroencephalogram (EEG) and electrocardiogram (ECG) signals. Eleven participants (28-52 years) attended 8 weeks of Mindfulness Based Stress Reduction (MBSR) training. EEG and ECG data of two states of mindful breathing and rest, both eye-closed, were recorded before and after the training. EEGLAB was used to analyze the alpha band (8-12 Hz) power, alpha peak frequency (APF), peak power and coherence. FMRIB toolbox was used to extract the ECG data. Heart coherence (HC) and heartbeat evoked potential (HEP) were calculated for further correlation analysis. After 8 weeks of MBSR training, the correlation between APF and HC increased significantly in the middle frontal region and bilateral temporal regions. The correlation between alpha coherence and heart coherence had similar changes, while alpha peak power did not reflect such changes. In contrast, spectrum analysis alone did not show difference before and after MBSR training. The brain works in rhythmic oscillation, and this rhythmic connection becomes more coherent with cardiac activity after 8 weeks of MBSR training. Individual APF is relatively stable and its interplay with cardiac activity may be a more sensitive index than power spectrum by monitoring the brain-heart connection. This preliminary study has important implications for the neuroscientific measurement of meditative practice.

Memristive field effect in a single and multilayer neural network with different connection topologies

The network connectivities play an important role in displaying the vastly different collective dynamics in many complex systems. To demonstrate the presence of different dynamical states and their transition, we consider Hindmarsh-Rose neurons, which are linked up by electromagnetic interactions. The dynamical behaviors of the proposed system are specifically explored under three distinct network connectivities: Regular(RG), small-world (SW), and random (RAND) interactions. We discover that increasing coupling intensity illustrates the dynamical transition from the desynchronization state to the traveling wave state for all the considered network interactions. Particularly, the regular network shows the emergence of spatial symmetric patterns that transit to a homogeneous steady state while increasing the strength of magnetic field interaction. In addition, the transition from an asymmetric pattern to an in-homogeneous steady state is noticed for small-world and random networks. The investigation is then extended to a three-layer multiplex network in which nodes interact electromagnetically within (intra-) layers and magnetically between (inter-) layers, since many complex networks in the real world have large numbers of nodes organized (or located) in different subnetworks. We show that increasing the coupling intensity leads to synchronization in all layers and, eventually, a rest state at high coupling strength.

Recurrence quantification analysis during a mental calculation task.

The identification of brain dynamical changes under different cognitive conditions with noninvasive techniques such as electroencephalography (EEG) is relevant for the understanding of their underlying neural mechanisms. The comprehension of these mechanisms has applications in the early diagnosis of neurological disorders and asynchronous brain computer interfaces. In both cases, there are no reported features that could describe intersubject and intra subject dynamics behavior accurately enough to be applied on a daily basis. The present work proposes the use of three nonlinear features (recurrence rate, determinism, and recurrence times) extracted from recurrence quantification analysis (RQA) to describe central and parietal EEG power series complexity in continuous alternating episodes of mental calculation and rest state. Our results demonstrate a consistent mean directional change of determinism, recurrence rate, and recurrence times between conditions. Increasing values of determinism and recurrence rate were present from the rest state to mental calculation, whereas recurrence times showed the opposite pattern. The analyzed features in the present study showed statistically significant changes between rest and mental calculation states in both individual and population analysis. In general, our study described mental calculation EEG power series as less complex systems in comparison to the rest state. Moreover, ANOVA showed stability of RQA features along time.

The Effect of Circadian Photoreceptors Stimulation on the Stress Response of Subjects with High Anxiety: A Pilot Study

The circadian and stress-realizing systems are interconnected, and the balance of their interaction determines the state of human health. The objective of this study was to investigate the modulating effect of activating the circadian system on heart rate variability in female medical students with high anxiety while performing a cognitive task. After 20 min of adequate stimulation of circadian photoreceptors with a monochromatic blue light, the cognitive task performance resulted in a decrease in sympathetic impact. During the session of monochromatic blue light exposure, a trend of increasing heart rate variability was observed in a state of relative rest (especially in the first 5 min). A comparative analysis of the parameters of the letter cancellation test before and after light exposure revealed a statistically significant increase in the indexes reflecting mental productivity, work accuracy, and concentration of attention. The results suggest an essential physiological role of the human circadian system in modulating the autonomic and psycho-emotional conditions, as well as cognitive functions of individuals with high anxiety. Our findings indicate the possibility of quickly correcting the balance in human systemic regulatory mechanisms using the activation of retinal circadian photoreceptors by blue light.

КРИТЕРІЇ ВІДБОРУ СЛУЖБОВИХ СОБАК ДЛЯ ДРЕСИРУВАННЯ ЗА НАПРЯМОМ РОЗШУКОВОЇ СЛУЖБИ

The article highlights the criteria for selecting service dogs of the State Criminal and Exsecutive Service of Ukraine for training in the framework of the search service. Defects, diseases and deficiencies with which service dogs of all types of training cannot be admitted to training as part of the department’s cynology teams are characterized. Recommendations are provided for determining the suitability of service dogs for training of the search service. The method of establishing the nature of the predominant reactions of the behavior of service dogs is characterized. For training, it is advisable to select dogs that are energetic, active, brave, mobile and quite excitable, i.e. choleric and sanguine. Phlegmatics and melancholics are not suitable for training. A refined technique with the help of which the nature of the prevailing reactions of the behavior of service dogs is established and their suitability or unsuitability for training according to the direction of the search service is determined. According to this criterion, service dogs are considered suitable for training if they have a predominant active-defense reaction, uniform development of orientational and active-orientational reactions, and uniform development of food and active-defense reactions. When determining the suitability of a service dog for training, the commission must examine it in a state of rest, and then in motion, establish its age, physical qualities, state of health, assess the acuity of smell, sight, and hearing and, in accordance with the specified methodology, establish the nature of the prevailing behavioral reactions. Therefore, the criteria used to determine the suitability of service dogs to undergo training as part of cynology teams of the search service are compliance with the established requirements regarding age, state of health, standards of constitution and exterior of the relevant breeds, the presence of a certain type of higher stressful activity and the necessary prevailing reactions of the body’s behavior, which are determined using the specified method. Taking into account the above criteria, during the selection of service dogs for training, in combination with educational training activities, will allow to achieve the educational goals of primary professional training of cynology teams with search dogs, in particular, and to bring the state of cynology support of the department into compliance with the specified requirements, as a whole. Key words: initial professional training, junior dog inspectors, criteria, selection, training, search dogs.

Change In Middle Cerebral Artery Pulsatility Index Over Time Due To Fetal Response To Defined Sound Stimulation: Human fetal responses to airborne sound stimulation

The estimation of fetal reactions to different stimuli indicates the cortical structure’s development and maturity. Recent studies pointed out that Pulsatility index (PI) changes could be associated with auditory stimulation. Each reaction to a particular stimulus has time dynamics which include: the period before the stimulus, the period during and immediately after the stimulus, the period of response and reaction to the stimulus, and the period of returning to the state of rest. Bearing in mind this principle, the preliminary results of the analysis of PI changes measured in the middle cerebral artery (MCA) as a fetal reaction to a defined sound stimulus are given in the paper. The study was conducted at the Clinic for Gynecology and Obstetrics "Narodni front" in Belgrade, Serbia. The research sample included 5 women with no-risk pregnancies. The PI measuring in fetal MCA was conducted in the period between the 31th and the 32nd week of gestation. The results indicate the time dynamics of PI change exist and point to the necessity of a different approach to PI measurement in the conditions of defined sound stimulation, concerning the procedures described so far in the literature.

Scale-free dynamics in the core-periphery topography and task alignment decline from conscious to unconscious states

Scale-free physiological processes are ubiquitous in the human organism. Resting-state functional MRI studies observed the loss of scale-free dynamics under anesthesia. In contrast, the modulation of scale-free dynamics during task-related activity remains an open question. We investigate scale-free dynamics in the cerebral cortex’s unimodal periphery and transmodal core topography in rest and task states during three conscious levels (awake, sedation, and anesthesia) complemented by computational modelling (Stuart-Landau model). The empirical findings demonstrate that the loss of the brain’s intrinsic scale-free dynamics in the core-periphery topography during anesthesia, where pink noise transforms into white noise, disrupts the brain’s neuronal alignment with the task’s temporal structure. The computational model shows that the stimuli’s scale-free dynamics, namely pink noise distinguishes from brown and white noise, also modulate task-related activity. Together, we provide evidence for two mechanisms of consciousness, temporo-spatial nestedness and alignment, suggested by the Temporo-Spatial Theory of Consciousness (TTC).

Detection of motor imagery based on short-term entropy of time–frequency representations

BackgroundMotor imagery is a cognitive process of imagining a performance of a motor task without employing the actual movement of muscles. It is often used in rehabilitation and utilized in assistive technologies to control a brain–computer interface (BCI). This paper provides a comparison of different time–frequency representations (TFR) and their Rényi and Shannon entropies for sensorimotor rhythm (SMR) based motor imagery control signals in electroencephalographic (EEG) data. The motor imagery task was guided by visual guidance, visual and vibrotactile (somatosensory) guidance or visual cue only.ResultsWhen using TFR-based entropy features as an input for classification of different interaction intentions, higher accuracies were achieved (up to 99.87%) in comparison to regular time-series amplitude features (for which accuracy was up to 85.91%), which is an increase when compared to existing methods. In particular, the highest accuracy was achieved for the classification of the motor imagery versus the baseline (rest state) when using Shannon entropy with Reassigned Pseudo Wigner–Ville time–frequency representation.ConclusionsOur findings suggest that the quantity of useful classifiable motor imagery information (entropy output) changes during the period of motor imagery in comparison to baseline period; as a result, there is an increase in the accuracy and F1 score of classification when using entropy features in comparison to the accuracy and the F1 of classification when using amplitude features, hence, it is manifested as an improvement of the ability to detect motor imagery.

A comprehensive literature review on the recent advances in braking systems technology using FEA

“An object remains in its state of rest or in motion until and unless acted upon by an external force” Newton’s first law of motion, Braking systems were made possible by this rule of Sir Isaac Newton, which states that the greater the vehicle’s speed, the greater the brake force needed to slow it down. This idea spawned several studies in the subject of braking, leading to its development, which in turn has given us the luxury of picking the most effective braking system for any given situation. This research analyses the thermomechanical behaviour of dry disc-to-pad contact during braking using Finite Element Analysis (FEA). Air ventilation and friction will be increased by modulating the design for disc heating issue due to long life of brake disc. The modeling of transient disc brake temperature is used to determine the disc’s geometric design for vehicle ventilation. The thermal-structural analysis is coupled to calculate disc deformation, Von Mises stress, as well as pad contact temperature distribution. The findings match the specialist literature.

Stability of Stationary Motions of Mechanical Systems with a Particular Goryachev-Chaplygin Integral

In the existing studies, the stationary motions in a mechanical system in the case of the existence of a partial Goryachev-Chaplygin integral are analyzed. Some invariant sets and their stability, including one of the stationary motions, are also studied. In this article, the stability of the remaining second rest state is finally investigated.