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Echolocation Jamming
Echolocation (or sonar) systems of animals, like human radar systems, are susceptible to interference known as echolocation jamming or sonar jamming. Jamming occurs when non-target sounds interfere with target echoes. Jamming can be purposeful or inadvertent, and can be caused by the echolocation system itself, other echolocating animals, prey, or humans. Echolocating animals have evolved to minimize jamming, however; echolocation avoidance behaviors are not always successful. Self jamming Echolocating animals can jam themselves in a number of ways. Bats, for example, produce some of the loudest sounds in nature, and then they immediately listen for echoes that are hundreds of times fainter than the sounds they emit. To avoid deafening themselves, whenever a bat makes an echolocation emission, a small muscle in the bat's middle ear (the stapedius muscle) clamps down on small bones called ossicles, which normally amplify sounds between the ear drum and the cochlea. This dampens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Echolocation
Echolocation, also called bio sonar, is a biological active sonar used by several animal groups, both in the air and underwater. Echolocating animals emit calls and listen to the Echo (phenomenon) , echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for animal navigation , navigation, foraging, and predation, hunting prey. Echolocation calls can be Frequency modulation, frequency modulated (FM, varying in pitch during the call) or constant frequency (CF). FM offers precise range discrimination to localize the prey, at the cost of reduced operational range. CF allows both the prey's velocity and its movements to be detected by means of the Doppler effect. FM may be best for close, cluttered environments, while CF may be better in open environments or for hunting while perched. Echolocating animals include mammals, especially odontocetes (toothed whales) and some bat species, and, using s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Jamming And Deception
Radar jamming and deception is a form of electronic countermeasures (ECMs) that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the radar with signals so its display cannot be read are normally known as jamming, while systems that produce confusing or contradictory signals are known as deception, but it is also common for all such systems to be referred to as jamming. There are two general classes of radar jamming, mechanical and electronic. Mechanical jamming entails reflecting enemy radio signals in various ways to provide false or misleading target signals to the radar operator. Electronic jamming works by transmitting additional radio signals towards enemy receivers, making it difficult to detect real target signals, or take advantage of known behaviors of automated systems like radar lock-on to confuse the system. Various Electronic counter-countermeasur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stapedius
The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or stirrup bone of the middle ear. Structure The stapedius emerges from a pinpoint foramen or opening in the apex of the pyramidal eminence (a hollow, cone-shaped prominence in the posterior wall of the tympanic cavity), and inserts into the neck of the stapes. Nerve supply The stapedius is supplied by the nerve to stapedius, a branch of the facial nerve. Function The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone. As one of the muscles involved in the acoustic reflex it prevents excess movement of the stapes, helping to control the amplitude of sound, sound waves from the general external environment to the inner ear. Clinical significance Paralysis of the stapedius allows wider oscillation of the stapes, resulting in heightened reaction of the Auditory Ossicles, audit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossicles
The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. Although the term "ossicle" literally means "tiny bone" (from Latin ''ossiculum'') and may refer to any small bone throughout the body, it typically refers specifically to the malleus, incus and stapes ("hammer, anvil, and stirrup") of the middle ear. The auditory ossicles serve as a kinematic chain to transmit and amplify ( intensify) sound vibrations collected from the air by the ear drum to the fluid-filled labyrinth ( cochlea). The absence or pathology of the auditory ossicles would constitute a moderate-to-severe conductive hearing loss. Structure The ossicles are, in order from the eardrum to the inner ear (from superficial to deep): the malleus, incus, and stapes, terms that in Latin are translated as "the hammer, anvil, and stirrup". * The malleus () articulates with the incus through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ear Drum
In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pressure of sound from the air to the ossicles inside the middle ear, and thence to the oval window in the fluid-filled cochlea. The ear thereby converts and amplifies vibration in the air to vibration in cochlear fluid. The malleus bone bridges the gap between the eardrum and the other ossicles. Rupture or perforation of the eardrum can lead to conductive hearing loss. Collapse or retraction of the eardrum can cause conductive hearing loss or cholesteatoma. Structure Orientation and relations The tympanic membrane is oriented obliquely in the anteroposterior, mediolateral, and superoinferior planes. Consequently, its superoposterior end lies lateral to its anteroinferior end. Anatomically, it relates superiorly to the middle cranial fos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlea
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus (cochlea), modiolus. A core component of the cochlea is the organ of Corti, the sensory organ of hearing, which is distributed along the partition separating the fluid chambers in the coiled tapered tube of the cochlea. Etymology The name 'cochlea' is derived from the Latin word for ''snail shell'', which in turn is from the Greek language, Ancient Greek κοχλίας ''kokhlias'' ("snail, screw"), and from κόχλος ''kokhlos'' ("spiral shell") in reference to its coiled shape; the cochlea is coiled in mammals with the exception of monotremes. Structure The cochlea (: cochleae) is a spiraled, hollow, conical chamber of bone, in which waves propagate from the base (near the middle ear and the oval window) to the apex (the top or center of the spiral). The spiral canal of the cochlea is a section of the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Fish
An electric fish is any fish that can Bioelectrogenesis, generate electric fields, whether to sense things around them, for defence, or to stun prey. Most fish able to produce shocks are also electroreceptive, meaning that they can sense electric fields. The only exception is the Uranoscopidae, stargazer family (Uranoscopidae). Electric fish, although a small minority of all fishes, include both oceanic and freshwater species, and both cartilaginous and bony fishes. Electric fish produce their electrical fields from an Electric organ (biology), electric organ. This is made up of electrocytes, modified muscle or nerve cells, specialized for producing strong electric fields, used to locate prey, for Anti-predator adaptation, defence against predators, and for Signalling theory, signalling, such as in courtship. Electric organ discharges are two types, pulse and wave, and vary both by species and by function. Electric fish have evolved many specialised behaviours. The predatory Cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jamming Avoidance Response
The jamming avoidance response is a behavior of some species of electric fish#Strongly and weakly electric fish, weakly electric fish. It occurs when two electric fish with wave discharges meet – if their discharge frequency, frequencies are very similar, each fish shifts its discharge frequency to increase the difference between the two. By doing this, both fish prevent jamming of their sense of electroreception. The behavior has been most intensively studied in the South American species ''Glass knifefish, Eigenmannia virescens''. It is also present in other Gymnotiformes such as ''Apteronotus'', as well as in the African species ''Gymnarchus niloticus''. The jamming avoidance response was one of the first complex behavioral responses in a vertebrate to have its neural circuitry completely specified. As such, it holds special significance in the field of neuroethology. Discovery The jamming avoidance response (JAR) was discovered by Akira Watanabe and Kimihisa Takeda in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Brown Bat
The big brown bat (''Eptesicus fuscus'') is a species of vesper bat distributed widely throughout North America, the Caribbean, and the northern portion of South America. It was first described as a species in 1796. Compared to other microbats, the big brown bat is relatively large, weighing and possessing a wingspan of . Big brown bats are insectivore, insectivorous, consuming a diverse array of insects, particularly night-flying insects, but especially beetles. Some of the beetles it consumes are serious agricultural pests, including cucumber beetles. They are nocturnal, foraging for prey at night and roosting in sheltered areas during the day such as caves, tunnels, tree cavities, and human structures. Their breeding season is in the fall, shortly before their annual hibernation. After hibernation ends in the spring, females form maternity colony, maternity colonies for giving birth to young. Oftentimes only one offspring is produced per litter, though twins are common in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctiidae
The Arctiinae (formerly called the family Arctiidae) are a large and diverse subfamily of moths with around 11,000 species found all over the world, including 6,000 neotropical species.Scoble, MJ. (1995). ''The Lepidoptera: Form, Function and Diversity''. Second ed. Oxford University Press. This subfamily includes the groups commonly known as tiger moths (or tigers), which usually have bright colours, footmen, which are usually much drabber, lichen moths, and wasp moths. Many species have "hairy" caterpillars that are popularly known as woolly bears or woolly worms. The scientific name Arctiinae refers to this hairiness (Gk. αρκτος = a bear). Some species within the Arctiinae have the word "tussock"' in their common names because they have been misidentified as members of the Lymantriinae subfamily based on the characteristics of the larvae. Taxonomy The subfamily was previously classified as the family Arctiidae of the superfamily Noctuoidea and is a monophyletic group. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bertholdia Trigona
''Bertholdia trigona'', or Grote's bertholdia, is a species of moth in the family Erebidae. The species was first described by Augustus Radcliffe Grote in 1879. It is prevalent in the southwestern United States. In studies performed at Wake Forest University, these moths were shown to have developed the ability Abilities are powers an agent has to perform various Action (philosophy), actions. They include common abilities, like walking, and rare abilities, like performing a double backflip. Abilities are intelligent powers: they are guided by the person ... to disrupt the echolocation of bats. This insect is one of several moths known to jam its predator's echolocation and has the highest recorded click rate of any moth species, a feature hypothesized to increase the effectiveness of jamming. References External links * *Corcoran, Aaron''SonarJamming.com'' Sensory and Movement Ecology Lab at UC Colorado Springs. {{Taxonbar, from=Q13403125 Phaegopterina Moths describe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
