scholarly journals Effects of the 27.12 MHz magnetic field emitted by short-wave equipment on spermatogenesis

2021 ◽  
Vol 43 ◽  
pp. e53934
Author(s):  
Márcio Botelho Pedrosa ◽  
Bruno Mendes Tenorio ◽  
Fernanda das Chagas Angelo Mendes Tenorio ◽  
Rosana Nogueira de Morais ◽  
Romildo de Albuquerque Nogueira ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Lamina Propria ◽  
Gonadosomatic Index ◽  
Short Wave ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Histopathological Analysis ◽  
Individual Volume

Studies have shown the influence of magnetic fields on several biological systems. Some of these fields, such as shortwave (SW) magnetic fields, have been used for therapeutic purposes. However, the possible adverse effects caused by this treatment still need to be better understood. The present study aimed to ascertain whether a single daily exposure (15 min.), for 15, 30 and 60 days, to SW magnetic field (27.12 MHz) can impede spermatogenesis. Exposure to SW magnetic fields did not change the weight of body, testis, epididymis, prostate, seminal vesicle or the gonadosomatic index. The plasma testosterone levels and testicular component volumes (seminiferous tubules, lumen, lamina propria, connective tissue, blood vessels, intertubular tissue) also remained unchanged. Histopathological analysis and spermatogenesis markers showed no changes after exposure to SW magnetic fields. However, some analyses showed changes in the lamina propria, daily sperm production, individual volume and population of Leydig cells. In conclusion, exposure to SW magnetic field for up to 60 days seems to be safe for spermatogenesis, but this exposure caused minor testicular changes that need to be better understood in the long term. This is of particular interest to health professionals who handle such SW devices for long periods of time.

scholarly journals Reconstructing solar magnetic fields from historical observations

2019 ◽  
Vol 627 ◽  
pp. A11
Author(s):  
I. O. I. Virtanen ◽  
I. I. Virtanen ◽  
A. A. Pevtsov ◽  
L. Bertello ◽  
A. Yeates ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Active Regions ◽  
Long Term Evolution ◽  
Photospheric Magnetic Field ◽  
Solar Magnetic Fields ◽  
Term Evolution ◽  
Large Scale Field

Aims. The evolution of the photospheric magnetic field has only been regularly observed since the 1970s. The absence of earlier observations severely limits our ability to understand the long-term evolution of solar magnetic fields, especially the polar fields that are important drivers of space weather. Here, we test the possibility to reconstruct the large-scale solar magnetic fields from Ca II K line observations and sunspot magnetic field observations, and to create synoptic maps of the photospheric magnetic field for times before modern-time magnetographic observations. Methods. We reconstructed active regions from Ca II K line synoptic maps and assigned them magnetic polarities using sunspot magnetic field observations. We used the reconstructed active regions as input in a surface flux transport simulation to produce synoptic maps of the photospheric magnetic field. We compared the simulated field with the observed field in 1975−1985 in order to test and validate our method. Results. The reconstruction very accurately reproduces the long-term evolution of the large-scale field, including the poleward flux surges and the strength of polar fields. The reconstruction has slightly less emerging flux because a few weak active regions are missing, but it includes the large active regions that are the most important for the large-scale evolution of the field. Although our reconstruction method is very robust, individual reconstructed active regions may be slightly inaccurate in terms of area, total flux, or polarity, which leads to some uncertainty in the simulation. However, due to the randomness of these inaccuracies and the lack of long-term memory in the simulation, these problems do not significantly affect the long-term evolution of the large-scale field.

Long-term stellar magnetic field study at the Crimean Astrophysical Observatory

2018 ◽  
Vol 13 (S340) ◽  
pp. 35-38
Author(s):  
Varvara Butkovskaya ◽  
Sergei Plachinda ◽  
Dilyara Baklanova
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Study ◽  
Crimean Astrophysical Observatory ◽  
Activity Cycles ◽  
Magnetic Cycles ◽  
Long Term Monitoring ◽  
The Magnetic Field ◽  
Term Monitoring

AbstractThe long-term monitoring of magnetic cycles is a key diagnostic in understanding how dynamo generation and amplification of magnetic fields occur in solar-like stars. One of the current key problems is the establishment of the magnetic field behavior during the activity cycles for stars of different ages and evolutionary statuses. We present the experience of using own long-term datasets for study of activity cycles in selected stars at the Crimean Astrophysical Observatory.

scholarly journals RADIATION FROM RELATIVISTIC SHOCKS WITH TURBULENT MAGNETIC FIELDS

2010 ◽  
Vol 19 (06) ◽  
pp. 715-721 ◽  
Author(s):  
K.-I. NISHIKAWA ◽  
J. NIMIEC ◽  
M. MEDVEDEV ◽  
B. ZHANG ◽  
P. HARDEE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Magnetic Fields ◽  
Weibel Instability ◽  
Pair Plasma ◽  
Nonlinear Stage ◽  
Relativistic Shocks ◽  
Electron Positron ◽  
Ambient Electron

Using our new 3D relativistic electromagnetic particle (REMP) code parallelized with MPI, we investigated long-term particle acceleration associated with a relativistic electron–positron jet propagating in an unmagnetized ambient electron–positron plasma. We have also performed simulations with electron-ion jets. The simulations were performed using a much longer simulation system than our previous simulations in order to investigate the full nonlinear stage of the Weibel instability for electron–positron jets and its particle acceleration mechanism. Cold jet electrons are thermalized and ambient electrons are accelerated in the resulting shocks for pair plasma case. Acceleration of ambient electrons leads to a maximum ambient electron density three times larger than the original value for pair plasmas. Behind the bow shock in the jet shock strong electromagnetic fields are generated. These fields may lead to time-dependent afterglow emission. We calculated radiation from electrons propagating in a uniform parallel magnetic field to verify the technique. We also used the new technique to calculate emission from electrons based on simulations with a small system with two different cases for Lorentz factors (15 and 100). We obtained spectra which are consistent with those generated from electrons propagating in turbulent magnetic fields with red noise. This turbulent magnetic field is similar to the magnetic field generated at an early nonlinear stage of the Weibel instability.

scholarly journals Effects of long-term maternal exposure to low doses of PCB126 and PCB153 on the reproductive system and related hormones of young male goats

Reproduction ◽  
2005 ◽  
Vol 130 (5) ◽  
pp. 731-742 ◽  
Author(s):  
Irma C Oskam ◽  
Jan L Lyche ◽  
Anette Krogenæs ◽  
Ragnar Thomassen ◽  
Janneche U Skaare ◽  
...  
Keyword(s):  
Body Weight ◽  
Adult Life ◽  
Endocrine Disrupting Compounds ◽  
Maternal Exposure ◽  
Sperm Chromatin ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Control Group ◽  
Foetal Development

In this study, female goats were orally exposed to PCB126 or PCB153, at 49 ng/kg body weight per day and 98 μg/kg body weight per day respectively, from gestational day 60 until delivery at approximately day 150. Exposure of the offspring continued via lactation until postnatal day 40. Reproductive toxicity in the male offspring was studied by the evaluation of conventional reproductive endpoints as well as flow cytometric analyses of spermatogenesis and sperm chromatin structure. PCB153-treated animals showed a significant smaller testis diameter in comparison to the control group. Neither of the treated groups showed differences for plasma FSH in comparison to controls. PCB153-treated animals differed significantly from the control group with respect to plasma LH and testosterone levels, whereas PCB126-treated animals only differed from the controls in plasma testosterone concentrations. Neither the PCB126 nor the PCB153 group differed from the controls with respect to the conventional sperm parameters or testis histology. A significant lower ratio of interstitium area to seminiferous tubules area and proportion of diploid testis cells were observed for the PCB153 group. Sperm from PCB153-treated animals showed a significantly higher percentage of sperm with damaged DNA. From the results of the present study it was concluded that PCB153 was able to induce alterations in reproductive endpoints related to the hypothalamic-pituitary-axis as well as to the testis. The effects observed in male kids after a long-term maternal exposure to PCB153 support the concept that exposure to endocrine-disrupting compounds during foetal development may lead to adverse reproductive effects in adult life.

The long-term variation of the effective magnetic field of the active star ε Eridani

2018 ◽  
Vol 13 (S340) ◽  
pp. 39-42
Author(s):  
Cesare Scalia ◽  
Francesco Leone ◽  
Manuele Gangi
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Effective Magnetic Field ◽  
Magnetic Signal ◽  
Active Star ◽  
Cool Stars ◽  
Term Variation ◽  
Line Slope ◽  
Stellar Magnetic Fields

AbstractLong-term periodicities of magnetic fields in cool stars are usually studied from activity indicators, which are only indirectly related to the presence of the field. Direct detections are complicated issues since even a complex magnetic structure, as the solar one, has a very low disk integrated magnetic signal, which is usually hidden in the noise level. We introduce a method for the direct measurement of small integrated longitudinal stellar magnetic fields (effective magnetic fields), called multi-line slope method, based on the regression of the Stokes V signal with respect to the first derivative of Stokes I. We present the results of the application of this technique to a dataset of 9 yr of observations of the active star epsilon Eridani, obtained with the spectropolarimeters Narval, HARPSpol and CAOS, showing that the long-term variation of the effective magnetic field corresponds to the period of the cycle retrieved by the activity indicators.

scholarly journals Chronic exposure of bisphenol S (BPS) affect hypothalamic-pituitary-testicular activities in adult male rats: possible in estrogenic mode of action

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Hizb Ullah ◽  
Faizan Ullah ◽  
Owais Rehman ◽  
Sarwat Jahan ◽  
Tayyaba Afsar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Chronic Exposure ◽  
Structural Changes ◽  
Gonadosomatic Index ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Bisphenol S ◽  
Daily Sperm Production

Abstract Background The industrial revolution has resulted in increased synthesis and the introduction of a variety of compounds into the environment and their potentially hazardous effects have been observed in the biota. The present study was aimed to evaluate the potential endocrine-disrupting effects of chronic exposure to the low concentrations of bisphenol S (BPS) in male rats. Methods Weaning male Sprague-Dawley rats (22 days old) were either exposed to water containing 0.1% ethanol for control or different concentrations of BPS (0.5, 5, and 50 μg/L) in drinking water for 48 weeks in the chronic exposure study. After completion of the experimental period, animals were dissected and different parameters (hormone concentrations, histology of testis and epididymis, oxidative stress and level of antioxidant enzymes in the testis, daily sperm production (DSP), and sperm parameters) were determined. Results Results of the present study showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organ weights. Oxidative stress in the testis was significantly elevated while sperm motility, daily sperm production, and the number of sperm in epididymis were reduced. Plasma testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations were reduced and estradiol levels were high in the 50 μg/L-exposed group. Histological observations involved a significant reduction in the epithelial height of the testis along with disrupted spermatogenesis, an empty lumen of the seminiferous tubules, and the caput region of the epididymis. Conclusion These results suggest that exposure to 5 and 50 μg/L of BPS for the chronic duration started from an early age can induce structural changes in testicular tissue architecture and endocrine alterations in the male reproductive system which may lead to infertility in males.

scholarly journals Magnetic fields in classical Be stars: results of our long-term program with FORS1 at the VLT

2010 ◽  
Vol 6 (S272) ◽  
pp. 222-223
Author(s):  
Ruslan V. Yudin ◽  
Swetlana Hubrig ◽  
Michail A. Pogodin ◽  
Markus Schoeller
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Magnetic Fields ◽  
Representative Sample ◽  
Be Stars ◽  
Low Resolution ◽  
Cyclic Variability ◽  
Be Star ◽  
The Magnetic Field

AbstractWe report the results of our search for magnetic fields in a representative sample of classical Be stars carried out during 2006-2008 using low-resolution spectropolarimetry with FORS1 at the VLT. Among the 28 classical Be stars studied, detections of a magnetic field were achieved in seven stars (i.e. ~25%). The detected magnetic fields are rather weak, not stronger than ~150G. Among the Be stars studied with time series, one Be star, λ Eri, displays cyclic variability of the magnetic field with a period of 21.12 min.

scholarly journals Spatial–temporal evolution of photospheric weak-field shifts in solar cycles 21–24

2021 ◽  
Vol 645 ◽  
pp. A47
Author(s):  
K. Mursula ◽  
T. Getachew ◽  
I. I. Virtanen
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Magnetic Fields ◽  
Large Scale ◽  
Temporal Evolution ◽  
Solar Surface ◽  
Weak Field ◽  
Solar Cycles ◽  
Field Shift

Context. Weak magnetic field elements make a dominant contribution to the total magnetic field on the solar surface. Even so, little is known of their long-term occurrence. Aims. We study the long-term spatial–temporal evolution of the weak-field shift and skewness of the distribution of photospheric magnetic field values during solar cycles 21−24 in order to clarify the role and relation of the weak field values to the overall magnetic field evolution. Methods. We used Wilcox Solar Observatory (WSO) and the Synoptic Optical Long-term Investigations of the Sun Vector SpectroMagnetograph synoptic maps to calculate weak-field shifts for each latitude bin of each synoptic map, and thereby constructed a time–latitude butterfly diagram for shifts. We also calculated butterfly diagrams for skewness for all field values and for weak field values only. Results. The weak-field shifts and (full-field) skewness depict a similar spatial–temporal solar cycle evolution to that of the large-scale surface magnetic field. The field distribution has a systematic non-zero weak-field shift and a large skewness already at (and after) the emergence of the active region, even at the highest resolution. We find evidence for coalescence of opposite-polarity fields during the surge evolution. This is clearly more effective at the supergranulation scale. However, a similar dependence of magnetic field coalescence on spatial resolution was not found in the unipolar regions around the poles. Conclusions. Our results give evidence for the preference of even the weakest field elements toward the prevailing magnetic polarity since the emergence of an active region, and for a systematic coalescence of stronger magnetic fields of opposite polarities to produce weak fields during surge evolution and at the poles. We also find that the supergranulation process is reduced or turned off in the unipolar regions around the poles. These observations improve the understanding not only of the development of the weakest magnetic field elements, but also of the dynamics of magnetic fields at large, and even of processes below the solar surface.

scholarly journals Long-term studies of photospheric magnetic fields on the Sun

2020 ◽  
Author(s):  
Alexei Pevtsov ◽  
Luca Bertello ◽  
Yuri Nagovitsyn ◽  
Andrey Tlatov ◽  
Valery Pipin
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Measurements ◽  
Sunspot Area ◽  
The Sun ◽  
Mount Wilson Observatory ◽  
History Of ◽  
Long Term Trends ◽  
Full Disk

We briefly review the history of observations of magnetic fields on the Sun, and  describe early magnetograps for full disk measurements. Changes in instruments and detectors, the cohort of observers, the knowledge base etc may result in non-uniformity of the long-term synoptic datasets. Still, such data are critical for detecting and understanding the long-term trends in solar activity. We demonstrate the value of historical data using studies of active region tilt (Joy's law) and the evolution of polar field and its reversal. Using the longest dataset of sunspot field strength measurements from Mount Wilson Observatory (1917-present) supplemented by shorter datasets from Pulkovo (1956--1997) and Crimean (1956--present) observatories we demonstrate that the magnetic properties of sunspots did not change over the last hundred years. We also show that the relationship between the sunspot area and its magnetic flux can be used to extend the studies of magnetic field in sunspots to periods with no direct magnetic field measurements. Finally, we show how more recent full disk observations of the vector magnetic field can be used to study the long-term (solar cycle) variations in  magnetic helicity on the Sun.

scholarly journals WATER IMBIBITION AND RADICLE GROWTH OF GERMINATING PEA, CORN, AND SOYBEAN SEEDS ORIENTED TO THE EAST, SOUTH, WEST, AND NORTH IN SIX DIFFERENT MAGNETIC FIELDS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 671b-671
Author(s):  
Benjamin Liang ◽  
John M. Brown
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Radicle Growth ◽  
Static Magnetic Fields ◽  
Water Imbibition ◽  
South West ◽  
Magnetic Resonance Imaging Mri ◽  
Water Saturated ◽  
Field Strengths

Magnetic Resonance Imaging (MRI) is currently considered as a nondestructive and noninvasive method for observing the distribution, concentration, and status of water in biological materials. However, effects of static magnetic fields of MRI systems on plant growth and development remain controversial. This study was conducted to investigate the water imbibition and radicle growth of Pisum sativum (cv. Little Marvel), Zea mays (cv. Pioneer 3379), and Glycine max (cv. Forrest) seeds oriented to four directions and exposed to six different magnetic field strengths commonly used in MRI systems. Seeds were embedded in a water saturated synthetic foam medium, and were oriented, with respect to their hilum or embryo, to the east, south, west, or north. Seeds were then exposed to either 2, 4, 6, 8, 10, or 15 kilogauss static magnetic fields for 48 hours (water imbibition) or 54 hours (radicle growth). The orientation of seeds and the magnetic field strengths had no effect on water imbibition or radicle growth of seeds tested. However, long term exposure retarded pea radicle growth in 2 KG treatment, enhanced soybean radicle growth in 10 KG treatment, but had no effect on corn radicle growth.

Sign in / Sign up

Export Citation Format

Share Document