AMBULATORY EFFECTS OF BRIEF EXPOSURES TO MAGNETIC FIELDS CHANGING ORTHOGONALLY IN SPACE OVER TIME

2007 ◽  
Vol 117 (3) ◽  
pp. 417-420
Author(s):  
L. S. ST-PIERRE ◽  
S. A. KOREN ◽  
M. A. PERSINGER
Keyword(s):  
Author(s):  
Е.Г. Екомасов ◽  
В.Н. Назаров ◽  
К.Ю. Самсонов ◽  
Р.Р. Муртазин

The generation and excitation of a magnetic soliton in a three-layer ferromagnet by constant magnetic fields and fields of variable frequency and small amplitude in the presence of dissipation in the system are considered. The analysis of the solutions of the equation of motion in an alternating field shows the possibility of increasing the amplitude of the magnetic soliton over time under certain conditions. The resonant effect is also affected by the geometric parameters of the thin layer: at a large layer width, the translational mode of the soliton oscillations is also excited.


2016 ◽  
Vol 12 (2) ◽  
pp. 4260-4269
Author(s):  
Esmail Abdo Mohammed Ali

In several residential and occupational studies, suppression of nocturnal melatonin in humans, which is induced by magnetic field, has been reported. The pineal gland produces melatonin and consider it as its major secretory product, which has a vital role in human well-being and health as it was suggested by the growing literature. Generally, exposure to the electric field has many biological effects, and the research on which has recently made this neurohormone, which is associated with the generation and classification of electric field, a focal point. To raise the risk of cancer through changing the pineal glands' regular functions and disrupting the melatonin's nocturnal increase in its release and synthesis, exposure to magnetic fields has been hypothesized. It is very essential to ascertain whether hormonal levers are changed during the exposure of humans to a magnetic field at night because the evidence for the "melatonin hypothesis" relies chiefly upon rodent data. The field-induced alterations were failed to be observed by all studies which have investigated the alterations in melatonin under controlled laboratory conditions when humans are exposed to a magnetic field. However, melatonin levels are altered through the exposure to low frequency magnetic fields, as it has been proposed by several observational studies in occupational and residential settings, which usually differ in terms of the presence of possible confounders, the individuals' health status and their general characteristics, the exposure conditions, and the attained measurement's precisions, durations and types. The associated differences in the duration of exposure may lead to this model of conflicting results. In the laboratory studies, only one night of exposure to a magnetic field was received by volunteers. In contrast, participants in the observational studies, usually for long periods on a daily basis, received chronic exposures to such fields. The consistent measurements of each melatonin over time is considered as another related possible explanation. It is unknown if the frequent magnetic field exposures suppress the inherent stability of each measurement of melatonin over time. In conclusion, the explanation of the contrasting results obtained in laboratory studies, and not in observational ones, could be helped by the evidence for improved suppression or increased variable measurements of melatonin attained in studies with longer controlled exposures.


2018 ◽  
Vol 41 ◽  
Author(s):  
David Hirshleifer ◽  
Siew Hong Teoh

AbstractEvolved dispositions influence, but do not determine, how people think about economic problems. The evolutionary cognitive approach offers important insights but underweights the social transmission of ideas as a level of explanation. The need for asocialexplanation for the evolution of economic attitudes is evidenced, for example, by immense variations in folk-economic beliefs over time and across individuals.


1994 ◽  
Vol 144 ◽  
pp. 559-564
Author(s):  
P. Ambrož ◽  
J. Sýkora

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.


1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.


2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.


2000 ◽  
Vol 179 ◽  
pp. 177-183
Author(s):  
D. M. Rust

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.


1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.


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