scholarly journals BIOFEEDBACK IN THE MAGNETIC FIELD (ON STEREOTOPOGRAPHY OF COGNITIVE FUNCTIONS)

2013 ◽  
Vol 12 (2) ◽  
pp. 7-20 ◽  
Author(s):  
K. G. Mazhirina ◽  
M. A. Pokrovskiy ◽  
M. V. Rezakova ◽  
A. A. Savelov ◽  
A. A. Sokolov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Self Regulation ◽  
Imitation Game ◽  
Middle Temporal ◽  
The Real ◽  
Cortical Areas ◽  
On Line ◽  
The Brain ◽  
The Magnetic Field ◽  
Qualitative Characteristics

The brain was mapped on-line using fMRI technology in the process of the development of self-regulation skills. We studied the dynamics of new neural networks being created in the real and simulated biofeedback models. It was shown that immersion in a virtual story brings about the large involvement of cortical areas, which are characterized by high values of voxels in the middle-temporal, occipital and frontal regions. We discuss the qualitative characteristics of the real and the imitation game periods.

scholarly journals Reversals in the large-scale αΩ-dynamo with memory

2015 ◽  
Vol 22 (4) ◽  
pp. 361-369 ◽  
Author(s):  
L. K. Feschenko ◽  
G. M. Vodinchar
Keyword(s):  
Magnetic Field ◽  
Power Law ◽  
Geomagnetic Field ◽  
Large Scale ◽  
Magnetic Polarity ◽  
Power Law Model ◽  
The Real ◽  
Geomagnetic Polarity ◽  
With Memory ◽  
The Magnetic Field

Abstract. Inversion of the magnetic field in a model of large-scale αΩ-dynamo with α-effect with stochastic memory is under investigation. The model allows us to reproduce the main features of the geomagnetic field reversals. It was established that the polarity intervals in the model are distributed according to the power law. Model magnetic polarity timescale is fractal. Its dimension is consistent with the dimension of the real geomagnetic polarity timescale.

scholarly journals Less Is Enough: Assessment of the Random Sampling Method for the Analysis of Magnetoencephalography (MEG) Data

2019 ◽  
Vol 24 (4) ◽  
pp. 98
Author(s):  
Cristina Campi ◽  
Annalisa Pascarella ◽  
Francesca Pitolli
Keyword(s):  
Magnetic Field ◽  
Random Sampling ◽  
Sampling Method ◽  
Brain Activity ◽  
Memory Storage ◽  
Non Invasive ◽  
Regularization Techniques ◽  
Ill Posed ◽  
The Brain ◽  
The Magnetic Field

Magnetoencephalography (MEG) aims at reconstructing the unknown neuroelectric activity in the brain from non-invasive measurements of the magnetic field induced by neural sources. The solution of this ill-posed, ill-conditioned inverse problem is usually dealt with using regularization techniques that are often time-consuming, and computationally and memory storage demanding. In this paper we analyze how a slimmer procedure, random sampling, affects the estimation of the brain activity generated by both synthetic and real sources.

Measurements of Magnetic Fields

1971 ◽  
Vol 43 ◽  
pp. 37-43
Author(s):  
M. Semel
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Stokes Parameters ◽  
Line Formation ◽  
On Line ◽  
The Magnetic Field

It is demonstrated that certain interrelations between the Stokes parameters are much less dependent on line formation than generally expected. Thus the dependence of these parameters on the magnetic field may be made more explicit and may lead to reliable calibration of polarimetric measurements in terms of magnetic field.

scholarly journals Whole brain mapping of glutamate in adult and old primates at 11.7T

2021 ◽  
Author(s):  
Clement M Garin ◽  
Nachiket A. Nadkarni ◽  
Jeremy Pepin ◽  
Julien Flament ◽  
Marc Dhenain
Keyword(s):  
Magnetic Field ◽  
Nucleus Accumbens ◽  
High Magnetic Field ◽  
Basal Forebrain ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Whole Brain ◽  
Cortical Areas ◽  
Age Related ◽  
The Brain

Glutamate is the amino acid with the highest cerebral concentration. It plays a central role in brain metabolism. It is also the principal excitatory neurotransmitter in the brain and is involved in multiple cognitive functions. Alterations of the glutamatergic system may contribute to the pathophysiology of many neurological disorders. For example, changes of glutamate availability are reported in rodents and humans during Alzheimer's and Huntington's diseases, epilepsy as well as during aging. Most studies evaluating cerebral glutamate have used invasive or spectroscopy approaches focusing on specific brain areas. Chemical Exchange Saturation Transfer imaging of glutamate (gluCEST) is a recently developed imaging technique that can map glutamate distribution in the entire brain with higher sensitivity and at higher resolution than previous techniques. It thus has strong potential clinical applications to assess glutamate changes in the brain. High field is a key condition to perform gluCEST images with a meaningful signal to noise ratio. Thus, even if some studies started to evaluate gluCEST in humans, most studies focused on rodent models that can be imaged at high magnetic field. In particular, systematic characterization of gluCEST contrast distribution throughout the whole brain has never been performed in humans or non-human primates. Here, we characterized for the first time the distribution of the glutamate index in the whole brain and in large-scale networks of mouse lemur primates at 11.7 Tesla. Because of its small size, this primate can be imaged in high magnetic field systems. It is widely studied as a model of cerebral aging or Alzheimer's disease. We observed high gluCEST contrast in cerebral regions such as the nucleus accumbens, septum, basal forebrain, cortical areas 24 and 25. Age-related alterations of this biomarker were detected in the nucleus accumbens, septum, basal forebrain, globus pallidus, hypophysis, cortical areas 24, 21, 6 and in olfactory bulbs. An age-related gluCEST contrast decrease was also detected in specific neuronal networks, such as fronto-temporal and evaluative limbic networks. These results outline regional differences of gluCEST contrast and strengthen its potential to provide new biomarkers of cerebral function in primates.

scholarly journals MHD simulation of flare situation above the active region AR 10365 in the real time scale.

2020 ◽  
Author(s):  
A.I. Podgorny ◽  
◽  
I.M. Podgorny ◽  
A.V. Borisenko ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Real Time ◽  
Time Scale ◽  
Rapid Change ◽  
Field Configuration ◽  
Mhd Simulation ◽  
The Real ◽  
Real Time Scale ◽  
The Magnetic Field

Since the configuration of the magnetic field in the corona, where solar flares appear, cannot be determined from observations, to study the flare situation, a numerical magnetohydrodynamic (MHD) simulation is carried out above the active region. MHD simulation performed in a greatly reduced (10 000 times) time scale permit to obtain results on the study of the solar flare mechanism, but the magnetic field configuration was distorted, especially near the photospheric boundary, due to the unnaturally rapid change in the field on the photosphere. For a more accurate study of the flare situation, MHD simulation in the real time scale was performed above the active region of AR 10365, which was made possible through the use of parallel calculations. The MHD simulation in the real scale of time above the AR 10365 during the first day of evolution showed the appearance of current density maxima with singular X-type line and plasma flow, which have to cause to the formation of a current sheet.

scholarly journals Simulations of the impact of small details on the magnetic fileld distribution for the compact superconducting cyclotron SC200 commissioning

2019 ◽  
Vol 201 ◽  
pp. 07002
Author(s):  
Dmitry Popov ◽  
Oleg Karamyshev ◽  
Galina Karamysheva ◽  
Vladimir Malinin ◽  
Grigori Shirkov
Keyword(s):  
Magnetic Field ◽  
Virtual Reality ◽  
Field Distribution ◽  
High Precision ◽  
High Performance ◽  
Magnetic Field Distribution ◽  
The Real ◽  
Superconducting Cyclotron ◽  
The Impact ◽  
The Magnetic Field

Modern packages for the design and simulation of cyclotron magnet systems, such as Tosca, CST Studio, Comsol, etc., combined with recent hardware of high performance, allow us to simulate and estimate even a subtle impact on the magnetic field distribution caused by small details and other systems of the accelerator. Such reckoning provides the data to perform and simulate the refilnement of the magnet called the ‘shimming’. That means a signifilcant part of the commissioning stage could be done in ‘virtual reality’. This could substantially decrease the duration of the shimming procedure of the real magnet and the amount of the material wasted on it, eventually this results in a fileld of high-precision which could be compared to real one.

The Bias-Controlled Magnetoimpedance Effect in a MIS Structure

2015 ◽  
Vol 233-234 ◽  
pp. 451-455
Author(s):  
Dmitry A. Smolyakov ◽  
Anton S. Tarasov ◽  
Arthur O. Gustaitsev ◽  
Nikita V. Volkov
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Mis Structure ◽  
Giant Magnetoimpedance ◽  
Metal Insulator ◽  
Giant Magnetoimpedance Effect ◽  
The Real ◽  
Mis Diode ◽  
The Magnetic Field ◽  
Pronounced Peak

We report the giant magnetoimpedance effect in a ferromagnetic metal/insulator/semiconductor (MIS) diode with the Schottky barrier based on the Fe/SiO2/n-Si structure. It was established that the applied magnetic field strongly influences the impedance of the structure in the temperature range 10—30 K. In this range, there is the pronounced peak in the temperature dependence of the real part of the impedance at frequencies from 10 Hz to 1 MHz. The effect of the magnetic field manifests itself as a shift of the peak of the real part of the impedance. Under the action of a bias voltage of 5 V, the peak of the real part of the impedance similarly shifts toward lower temperatures with and without applied magnetic field.

scholarly journals Thermo-magnetic nonlocal NJL model in the real and imaginary time formalisms

2017 ◽  
Vol 32 (04) ◽  
pp. 1750027 ◽  
Author(s):  
F. Márquez ◽  
R. Zamora
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Analytic Structure ◽  
Imaginary Time ◽  
Field Limit ◽  
The Real ◽  
Magnetic Catalysis ◽  
Time Formalism ◽  
Deconfinement Phase Transition ◽  
The Magnetic Field

In this paper, we study a nonlocal Nambu–Jona-Lasinio (nNJL) model with a Gaussian regulator in presence of a uniform magnetic field. We take a mixed approach to the incorporation of temperature in the model, and consider aspects of both real and imaginary time formalisms. We include confinement in the model through the quasiparticle interpretation of the poles of the propagator. By working in the real time formalism and computing the spectral density function, we find that the effect of the magnetic field on the poles of the propagator can be entirely absorbed within the mean field value of the scalar field. The analytic structure of our propagator is then preserved in the weak magnetic field limit. The effect of the magnetic field in the deconfinement phase transition is then studied. It is found that, like with chiral symmetry restoration, magnetic catalysis occurs for the deconfinement phase transition. It is also found that the magnetic field enhances the thermodynamical instability of the system. We work in the weak field limit, i.e. [Formula: see text]. At this level there is no splitting of the critical temperatures for chiral and deconfinement phase transitions.

A Robust NavigationMethod for Mobile Robots in Real-World Environments

2014 ◽  
Vol 26 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Sam Ann Rahok ◽  
◽  
Hirohisa Oneda ◽  
Akio Tanaka ◽  
Koichi Ozaki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mobile Robot ◽  
Mobile Robots ◽  
Real World ◽  
Laser Range ◽  
The Real ◽  
Laser Range Scanner ◽  
Lateral Error ◽  
The Magnetic Field ◽  
Navigation Method

This paper describes a robust navigation method for real-world environments. The method uses a 3-axis magnetic sensor and a laser range scanner. The magnetic field that occurs in the environment is used as key landmarks in the proposed navigation method, and physical landmarks scanned by the laser range scanner are taken into account in compensating for the mobile robot’s lateral error. An evaluation experiment was conducted during the final run of the Real World Robot Challenge (RWRC) 2013, and the result showed that the mobile robot equipped with the proposed method robustly navigated a 1.6 km course.

scholarly journals Stark-Zeeman Broadening of Spectral Line Shapes in Magnetized Plasmas

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 91
Author(s):  
Kamel Ahmed Touati ◽  
Keltoum Chenini ◽  
Mohammed Tayeb Meftah
Keyword(s):  
Magnetic Field ◽  
Spectral Line ◽  
Stark Effect ◽  
Line Broadening ◽  
Lyman Alpha ◽  
Line Shapes ◽  
Field Temperature ◽  
Motional Stark Effect ◽  
On Line ◽  
The Magnetic Field

In this work, we studied the Lyman-alpha line in the presence of a magnetic field, such as the ones found at the edge of tokamaks. The emphasis is on the contribution of the motional Stark effect on line broadening, which may have comparable effects to the internal plasma microfields for the spectral line in question. The effect of the magnetic field, temperature, and the Maxwell distribution of the ion velocities and density on Lyman-alpha are studied.

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