Waves produced by lightning strikes can bounce back and forth between Earth and the ionosphere the atmosphere layer with a high concentration of ions and free electrons , according to Phys.
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These lightning disturbances can distort important radio signals traveling to satellites. AM radio frequency bands fall between kilohertz to 1. AM radio has a long range, particularly at night when the ionosphere is better at refracting the waves back to earth, but it is subject to interference that affects the sound quality.
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When a signal is partially blocked — for example, by a metal-walled building such as a skyscraper — the volume of the sound is reduced accordingly. These bands typically use "frequency modulation" FM to encode, or impress, an audio or data signal onto the carrier wave. In frequency modulation, the amplitude maximum extent of the signal remains constant while the frequency is varied higher or lower at a rate and magnitude corresponding to the audio or data signal.
FM results in better signal quality than AM because environmental factors do not affect the frequency the way they affect amplitude, and the receiver ignores variations in amplitude as long as the signal remains above a minimum threshold. FM radio frequencies fall between 88 megahertz and megahertz, according to How Stuff Works. Shortwave radio uses frequencies in the HF band, from about 1.
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Within that range, the shortwave spectrum is divided into several segments, some of which are dedicated to regular broadcasting stations, such as the Voice of America, the British Broadcasting Corp. Throughout the world, there are hundreds of shortwave stations, according to the NASB. Shortwave stations can be heard for thousands of miles because the signals bounce off the ionosphere, and rebound back hundreds or thousands of miles from their point of origin. SHF and EHF represent the highest frequencies in the radio band and are sometimes considered to be part of the microwave band.
Molecules in the air tend to absorb these frequencies, which limits their range and applications. However, their short wavelengths allow signals to be directed in narrow beams by parabolic dish antennas satellite dish antennas. This allows for short-range high-bandwidth communications to occur between fixed locations.
SHF can work only in line-of-sight paths as the waves tend to bounce off objects like cars, boats and aircraft, according to the RF Page. And because the waves bounce off objects, SHF can also be used for radar. Outer space is teeming with sources of radio waves: planets, stars, gas and dust clouds, galaxies, pulsars and even black holes.
By studying these, astronomers can learn about the motion and chemical composition of these cosmic sources as well as the processes that cause these emissions. A radio telescope "sees" the sky very differently than it appears in visible light. Instead of seeing point-like stars, a radio telescope picks up distant pulsars, star-forming regions and supernova remnants. Then, mice headed to the usual location of the treat, probably using landmarks to orientate, but other times they just relied on the memorized sequence of left and right turns and ended up in the wrong maze arm.
Meticulous analyses of the brain data revealed that when the mice used their memory the place field cells oscillated in the same frequency as the memory cells at 35 Hz , but tuned into the vibe of the sensory cells when they appeared to be using landmarks 60 Hz. To further clarify the different roles of memory and sensory input to the mental map, the researchers repeated the experiment with knock out mice in which the gene coding for the NMDA-receptor was blocked.
To our surprise, the knock out mice weren't able to send information from their sensory system to the mental map at all. Materials provided by Radboud University Nijmegen.
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Information transfer within the brain Using implants in the brains of mice, the neuroscientists have found the first direct proof of the way the brain tuning knob works. Micro wire-tapping The researchers used a maze in the shape of the Pentagon, with five corridors in which a treat was hidden or not.
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Data analysis challenge Meticulous analyses of the brain data revealed that when the mice used their memory the place field cells oscillated in the same frequency as the memory cells at 35 Hz , but tuned into the vibe of the sensory cells when they appeared to be using landmarks 60 Hz. Journal Reference : Cabral et al. Oscillatory dynamics and place field maps reflect sequence and place memory processing in hippocampal ensembles under NMDA receptor control.
Neuron , January ScienceDaily, 22 January Radboud University Nijmegen. Brain works like a radio receiver.
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Retrieved September 21, from www. They found that people with schizophrenia It also knows which parts belong to a whole. If, for example, we direct our attention to the Below are relevant articles that may interest you.
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