1,721,478 research outputs found
REMARKS ON THE MEASUREMENT OF STATIC PERMITTIVITY THROUGH A CLASSICAL DESCRIPTION
No full textIn this paper the concept of static electric permittivity and its measurement are discussed. A classical description of polarization via a harmonically bound charge model is revisited and the evolution of the polarization concept in the presence of free electrons is shown. Various electrostatic problems are defined under ideal conditions. The measurement procedures for characterizing the static permittivity of dielectrics and conductors via the measurement of induction-electric field, charge-potential difference and electrostatic energy variation are discussed. Two basic experiments with a lossy dielectric are described. In one case we reach an electrostatic equilibrium with an indeterminate solution. In the other case we define a magnetostatic problem. Finally, we comment on the case of a laboratory experiment remarking on the proper use of the low-frequency limit of dielectric constant and showing experimental results performed on a supercapacitor
Low-Intensity Transcranial Ultrasound Stimulation: Mechanisms of Action and Rationale for Future Applications in Movement Disorders
Full text linkLow-intensity transcranial ultrasound stimulation (TUS) is a novel non-invasive brain stimulation technique that uses acoustic energy to induce changes in neuronal activity. However, although low-intensity TUS is a promising neuromodulation tool, it has been poorly studied as compared to other methods, i.e., transcranial magnetic and electrical stimulation. In this article, we first focus on experimental studies in animals and humans aimed at explaining its mechanisms of action. We then highlight possible applications of TUS in movement disorders, particularly in patients with parkinsonism, dystonia, and tremor. Finally, we highlight the knowledge gaps and possible limitations that currently limit potential TUS applications in movement disorders. Clarifying the potential role of TUS in movement disorders may further promote studies with therapeutic perspectives in this field
Keep boosting insight into the role of the primary motor cortex in Parkinson's disease pathophysiology
No full textPathophysiology of rigidity in Parkinson's disease: Another step forward
No full textnot applicable (editorial
Analytical estimation of the scale of earth-like planetary magnetic fields
No full textIn this paper we analytically estimate the magnetic field scale of planets with physical core conditions similar to that of Earth from a statistical physics point of view. We evaluate the magnetic field on the basis of the physical parameters of the center of the planet, such as density, temperature, and core size. We look at the contribution of the Seebeck effect on the magnetic field, showing that a thermally induced electrical current can exist in a rotating fluid sphere. We apply our calculations to Earth, where the currents would be driven by the temperature difference at the outer-inner core boundary, Jupiter and the Jupiter’s satellite Ganymede. In each case we show that the thermal generation of currents leads to a magnetic field scale comparable to the observed fields of the considered celestial bodies
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