Different types of Very Low Frequency Emissions (VLF) Observed at Low Latitude Station Varanasi

2010 ◽  
Author(s):  
R. P. Patel ◽  
A. K. Singh ◽  
Sandip K. Chakrabarti
Keyword(s):  
Low Frequency ◽  
Low Latitude ◽  
Very Low Frequency ◽  
Latitude Station ◽  
Different Types

VLF/LF (Very Low Frequency/Low Frequency) Reflection Properties of the Low Latitude Ionosphere

1988 ◽  
Author(s):  
Wayne I. Klemetti ◽  
Paul A. Kossey ◽  
John E. Rasmussen ◽  
Maria Sueli Da Silveira Macedo Moura
Keyword(s):  
Low Frequency ◽  
Low Latitude ◽  
Very Low Frequency ◽  
Low Latitude Ionosphere

Daytime observations of chorus emissions at low latitude

1994 ◽  
Vol 72 (1-2) ◽  
pp. 73-79 ◽  
Author(s):  
R. P. Singh ◽  
U. P. Singh ◽  
Ashok Kumar Singh ◽  
D. P. Singh
Keyword(s):  
Low Frequency ◽  
Resonance Interaction ◽  
Whistler Waves ◽  
Low Latitude ◽  
Energetic Electrons ◽  
Very Low Frequency ◽  
Ground Station ◽  
Transverse Resonance

Discrete very-low-frequency chorus emissions observed during the daytime at ground station Gulmarg (geomag. lat. 24°10′N) are reported. The generation of these emissions is explained in terms of transverse resonance interaction between whistler waves and counter-streaming energetic electrons. The theory is tested by evaluating different parameters.

scholarly journals Considerations Regarding Anodontia in Dental Medical Practice

2018 ◽  
Vol 24 (4) ◽  
pp. 195-199
Author(s):  
Iordan Dumitru Andreea Dona ◽  
Kozma Andrei ◽  
Bodnar Cristina ◽  
Agop-Forna Doriana
Keyword(s):  
Medical Practice ◽  
Case History ◽  
Low Frequency ◽  
Third Molars ◽  
The Real ◽  
Very Low Frequency ◽  
Dental Office ◽  
Different Types ◽  
Males And Females ◽  
Phylogenetic Evolution

Abstract Aim: This article is set on presenting various types of anodontia, the most frequent types found in a dental office and to bring awareness to parents and also the dentists on the signs of agenesis and its consequences in time. Material and method: for a year (1st September 2017 – 31th August 2018) various patients with different types and locations of anodontia were diagnosed correctly by an oral and radiological exam in a dental office. Results. Anodontia is found almost equally in both sexes without major differences between males and females. Real agenesis is most frequently found in the second premolars – study reports show that this is because of phylogenetic evolution. False agenesis is more frequent in the 3rd molars because they are most likely extracted. Third molars are usually extracted because they don’t have space to emerge on the maxilla or mandible or they emerge in a vicious position. Canine agenesis has a very low frequency. Conclusions: It is very important to do a thorough check-up and a correct case history followed by radiological investigations each time a suspicion of a possible anodontia exists. It can only be certainly diagnosed by having a full oral and radiological exam. Also a difference must be made between the real, false and pseudoanaodontia.

scholarly journals Sub-ionospheric very low frequency perturbations associated with the 12 May 2008 <i>M</i> = 7.9 Wenchuan earthquake

2013 ◽  
Vol 13 (9) ◽  
pp. 2331-2336 ◽  
Author(s):  
A. K. Maurya ◽  
R. Singh ◽  
B. Veenadhari ◽  
S. Kumar ◽  
A. K. Singh
Keyword(s):  
Wenchuan Earthquake ◽  
Southwest China ◽  
Low Frequency ◽  
Amplitude Fluctuation ◽  
Fluctuation Analysis ◽  
Low Latitude ◽  
Amplitude Variation ◽  
Very Low Frequency ◽  
Wave Channel ◽  
Potential Factors

Abstract. The present study reports the VLF (very low frequency) sub-ionospheric perturbations observed on transmitter JJI (22.1 kHz), Japan, received at the Indian low-latitude station, Allahabad ( geographic lat. 25.41° N, long 81.93° E), due to Wenchuan earthquake (EQ) that occurred on 12 May 2008 with the magnitude 7.9 and at the depth of 19 km in Sichuan province of Southwest China, located at 31.0° N, 103.4° E. The nighttime amplitude fluctuation analysis gives a significant increase in fluctuation and dispersion two days before EQ, when it crosses 2σ criterion. However, there was no significant change observed in the amplitude trend. The diurnal amplitude variation shows a significant increase in the amplitude of JJI signal on 11 and 12 May 2008. The gravity wave channel and changes in the electric field associated with this EQ seem to be the potential factors of the observed nighttime amplitude fluctuation, dispersion, and significant increase in the signal strength.

SOME CHARACTERISTICS OF THE LOWER HYBRID RESONANCE NOISE BANDS OBSERVED BY THE ALOUETTE I SATELLITE

1967 ◽  
Vol 45 (1) ◽  
pp. 13-19 ◽  
Author(s):  
D. J. McEwen ◽  
R. E. Barrington
Keyword(s):  
Low Frequency ◽  
Lower Hybrid ◽  
Frequency Of Occurrence ◽  
Maximum Frequency ◽  
Very Low Frequency ◽  
Hybrid Resonance ◽  
Different Types ◽  
Excitation Mechanisms ◽  
Night And Day ◽  
Lower Hybrid Resonance

An investigation has been made of the occurrence as a function of latitude and time of lower hybrid resonance (LHR) noise bands as recorded during 1963 and 1964 by the very-low-frequency receiver aboard the Alouette I satellite. Two different types of LHR noise are observed—polar and mid-latitude. Polar LHR noise bands, with the maximum frequency of occurrence at about 75° invariant latitude, are observed approximately one half of the time throughout the year and during both night and day. Mid-latitude LHR noise bands have a maximum frequency of occurrence at about 55° and are observed mainly during the months of June–October and primarily at night. The differences in appearance and occurrence of these two types of LHR noise suggest different excitation mechanisms.

The Attenuation of Very Low Frequency Brain Oscillations in Transitions from a Rest State to Active Attention

2009 ◽  
Vol 23 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Suzannah K. Helps ◽  
Samantha J. Broyd ◽  
Christopher J. James ◽  
Anke Karl ◽  
Edmund J. S. Sonuga-Barke
Keyword(s):  
Brain Activity ◽  
Sampling Rate ◽  
Low Frequency ◽  
Future Research ◽  
Adhd Symptoms ◽  
Default Mode ◽  
Very Low Frequency ◽  
Wide Range ◽  
Interference Hypothesis ◽  
Mode Interference

Background: The default mode interference hypothesis ( Sonuga-Barke & Castellanos, 2007 ) predicts (1) the attenuation of very low frequency oscillations (VLFO; e.g., .05 Hz) in brain activity within the default mode network during the transition from rest to task, and (2) that failures to attenuate in this way will lead to an increased likelihood of periodic attention lapses that are synchronized to the VLFO pattern. Here, we tested these predictions using DC-EEG recordings within and outside of a previously identified network of electrode locations hypothesized to reflect DMN activity (i.e., S3 network; Helps et al., 2008 ). Method: 24 young adults (mean age 22.3 years; 8 male), sampled to include a wide range of ADHD symptoms, took part in a study of rest to task transitions. Two conditions were compared: 5 min of rest (eyes open) and a 10-min simple 2-choice RT task with a relatively high sampling rate (ISI 1 s). DC-EEG was recorded during both conditions, and the low-frequency spectrum was decomposed and measures of the power within specific bands extracted. Results: Shift from rest to task led to an attenuation of VLFO activity within the S3 network which was inversely associated with ADHD symptoms. RT during task also showed a VLFO signature. During task there was a small but significant degree of synchronization between EEG and RT in the VLFO band. Attenuators showed a lower degree of synchrony than nonattenuators. Discussion: The results provide some initial EEG-based support for the default mode interference hypothesis and suggest that failure to attenuate VLFO in the S3 network is associated with higher synchrony between low-frequency brain activity and RT fluctuations during a simple RT task. Although significant, the effects were small and future research should employ tasks with a higher sampling rate to increase the possibility of extracting robust and stable signals.

Quantitative Analysis of Swarming Pulsive Microdischarges by using Very Low Frequency Voltage Applications

1995 ◽  
Vol 115 (10) ◽  
pp. 1174-1178
Author(s):  
Takahiro Ishida ◽  
Masayuki Nagao ◽  
Masamitsu Kosaki
Keyword(s):  
Quantitative Analysis ◽  
Low Frequency ◽  
Very Low Frequency
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