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baby travel system definition image
Q. how are they made?
Answer
In physics, a wormhole is a hypothetical topological feature of spacetime that is basically a 'shortcut' through space and time. A wormhole has at least two mouths which are connected to a single throat or tube. If the wormhole is traversable, matter can 'travel' from one mouth to the other by passing through the throat. While there is no observational evidence for wormholes, spacetimes containing wormholes are known to be valid solutions in general relativity.
The term wormhole was coined by the American theoretical physicist John Wheeler in 1957. However, the idea of wormholes was invented already in 1921 by the German mathematician Hermann Weyl in connection with his analysis of mass in terms of electromagnetic field energy.[1]
The name "wormhole" comes from an analogy used to explain the phenomenon. If a worm is travelling over the skin of an apple, then the worm could take a shortcut to the opposite side of the apple's skin by burrowing through its center, rather than travelling the entire distance around, just as a wormhole traveler could take a shortcut to the opposite side of the universe through a topologically nontrivial tunnel.
The basic notion of an intra-universe wormhole is that it is a compact region of spacetime whose boundary is topologically trivial but whose interior is not simply connected. Formalizing this idea leads to definitions such as the following, taken from Matt Visser's Lorentzian Wormholes:
If a Lorentzian spacetime contains a compact region Ω, and if the topology of Ω is of the form Ω ~ R x Σ, where Σ is a three-manifold of nontrivial topology, whose boundary has topology of the form dΣ ~ S2, and if, furthermore, the hypersurfaces Σ are all spacelike, then the region Ω contains a quasipermanent intra-universe wormhole.
Characterizing inter-universe wormholes is more difficult. For example, one can imagine a 'baby' universe connected to its 'parent' by a narrow 'umbilicus'. One might like to regard the umbilicus as the throat of a wormhole, but the space time is simply connected.
[edit] Wormhole types
Intra-universe wormholes connect one location of a universe to another location of the same universe (in the same present time or unpresent). A wormhole should be able to connect distant locations in the universe by creating a shortcut through spacetime, allowing travel between them that is faster than it would take light to make the journey through normal space. See the image above. Inter-universe wormholes connect one universe with another [1], [2]. This gives rise to the speculation that such wormholes could be used to travel from one parallel universe to another. A wormhole which connects (usually closed) universes is often called a Schwarzschild wormhole. Another application of a wormhole might be time travel. In that case, it is a shortcut from one point in space and time to another. In string theory, a wormhole has been envisioned to connect two D-branes, where the mouths are attached to the branes and are connected by a flux tube [3]. Finally, wormholes are believed to be a part of spacetime foam [4]. There are two main types of wormholes: Lorentzian wormholes and Euclidean wormholes. Lorentzian wormholes are mainly studied in general relativity and semiclassical gravity, while Euclidean wormholes are studied in particle physics. Traversable wormholes are a special kind of Lorentzian wormholes which would allow a human to travel from one side of the wormhole to the other. Serguei Krasnikov suggested the term spacetime shortcut as a more general term for (traversable) wormholes and propulsion systems like the Alcubierre drive and the Krasnikov tube to indicate hyperfast interstellar travel.
[edit] Theoretical basis
It is known that (Lorentzian) wormholes are not excluded within the framework of general relativity, but the physical plausibility of these solutions is uncertain. It is also unknown whether a theory of quantum gravity, merging general relativity with quantum mechanics, would still allow them. Most known solutions of general relativity which allow for traversable wormholes require the existence of exotic matter, a theoretical substance which has negative energy density. However, it has not been mathematically proven that this is an absolute requirement for traversable wormholes, nor has it been established that exotic matter cannot exist.
In March 2005, Amos Ori envisioned a wormhole which allows time travel, does not require any exotic matter and satisfies the weak, dominant, and strong energy conditions [5]. The stability of this solution is uncertain, so it is unclear whether infinite precision would be required for it to form in a way that allows time travel and also whether quantum effects would uphold chronology protection in this case, as analyses using semiclassical gravity have suggested they might do in the case of traversable wormholes.
[edit] Schwarzschild wormholes
Embedded diagram of a Schwarzschild wormhole.Lorentzian wormholes known as Schwarzschild wormholes or Einstein-Rosen bridges are bridges between areas of space that can be modeled as vacuum solutions to the Einstein field equations by combining models of a black hole and a white hole. This solution was discovered by Albert Einstein and his colleague Nathan Rosen, who first published the result in 1935. However, in 1962 John A. Wheeler and Robert W. Fuller published a paper showing that this type of wormhole is unstable, and that it will pinch off instantly as soon as it forms, preventing even light from making it through.
Before the stability problems of Schwarzschild wormholes were apparent, it was proposed that quasars were white holes forming the ends of wormholes of this type.
While Schwarzschild wormholes are not traversable, their existence inspired Kip Thorne to imagine traversable wormholes created by holding the 'throat' of a Schwarzschild wormhole open with exotic matter (material that has negative mass/energy).
In physics, a wormhole is a hypothetical topological feature of spacetime that is basically a 'shortcut' through space and time. A wormhole has at least two mouths which are connected to a single throat or tube. If the wormhole is traversable, matter can 'travel' from one mouth to the other by passing through the throat. While there is no observational evidence for wormholes, spacetimes containing wormholes are known to be valid solutions in general relativity.
The term wormhole was coined by the American theoretical physicist John Wheeler in 1957. However, the idea of wormholes was invented already in 1921 by the German mathematician Hermann Weyl in connection with his analysis of mass in terms of electromagnetic field energy.[1]
The name "wormhole" comes from an analogy used to explain the phenomenon. If a worm is travelling over the skin of an apple, then the worm could take a shortcut to the opposite side of the apple's skin by burrowing through its center, rather than travelling the entire distance around, just as a wormhole traveler could take a shortcut to the opposite side of the universe through a topologically nontrivial tunnel.
The basic notion of an intra-universe wormhole is that it is a compact region of spacetime whose boundary is topologically trivial but whose interior is not simply connected. Formalizing this idea leads to definitions such as the following, taken from Matt Visser's Lorentzian Wormholes:
If a Lorentzian spacetime contains a compact region Ω, and if the topology of Ω is of the form Ω ~ R x Σ, where Σ is a three-manifold of nontrivial topology, whose boundary has topology of the form dΣ ~ S2, and if, furthermore, the hypersurfaces Σ are all spacelike, then the region Ω contains a quasipermanent intra-universe wormhole.
Characterizing inter-universe wormholes is more difficult. For example, one can imagine a 'baby' universe connected to its 'parent' by a narrow 'umbilicus'. One might like to regard the umbilicus as the throat of a wormhole, but the space time is simply connected.
[edit] Wormhole types
Intra-universe wormholes connect one location of a universe to another location of the same universe (in the same present time or unpresent). A wormhole should be able to connect distant locations in the universe by creating a shortcut through spacetime, allowing travel between them that is faster than it would take light to make the journey through normal space. See the image above. Inter-universe wormholes connect one universe with another [1], [2]. This gives rise to the speculation that such wormholes could be used to travel from one parallel universe to another. A wormhole which connects (usually closed) universes is often called a Schwarzschild wormhole. Another application of a wormhole might be time travel. In that case, it is a shortcut from one point in space and time to another. In string theory, a wormhole has been envisioned to connect two D-branes, where the mouths are attached to the branes and are connected by a flux tube [3]. Finally, wormholes are believed to be a part of spacetime foam [4]. There are two main types of wormholes: Lorentzian wormholes and Euclidean wormholes. Lorentzian wormholes are mainly studied in general relativity and semiclassical gravity, while Euclidean wormholes are studied in particle physics. Traversable wormholes are a special kind of Lorentzian wormholes which would allow a human to travel from one side of the wormhole to the other. Serguei Krasnikov suggested the term spacetime shortcut as a more general term for (traversable) wormholes and propulsion systems like the Alcubierre drive and the Krasnikov tube to indicate hyperfast interstellar travel.
[edit] Theoretical basis
It is known that (Lorentzian) wormholes are not excluded within the framework of general relativity, but the physical plausibility of these solutions is uncertain. It is also unknown whether a theory of quantum gravity, merging general relativity with quantum mechanics, would still allow them. Most known solutions of general relativity which allow for traversable wormholes require the existence of exotic matter, a theoretical substance which has negative energy density. However, it has not been mathematically proven that this is an absolute requirement for traversable wormholes, nor has it been established that exotic matter cannot exist.
In March 2005, Amos Ori envisioned a wormhole which allows time travel, does not require any exotic matter and satisfies the weak, dominant, and strong energy conditions [5]. The stability of this solution is uncertain, so it is unclear whether infinite precision would be required for it to form in a way that allows time travel and also whether quantum effects would uphold chronology protection in this case, as analyses using semiclassical gravity have suggested they might do in the case of traversable wormholes.
[edit] Schwarzschild wormholes
Embedded diagram of a Schwarzschild wormhole.Lorentzian wormholes known as Schwarzschild wormholes or Einstein-Rosen bridges are bridges between areas of space that can be modeled as vacuum solutions to the Einstein field equations by combining models of a black hole and a white hole. This solution was discovered by Albert Einstein and his colleague Nathan Rosen, who first published the result in 1935. However, in 1962 John A. Wheeler and Robert W. Fuller published a paper showing that this type of wormhole is unstable, and that it will pinch off instantly as soon as it forms, preventing even light from making it through.
Before the stability problems of Schwarzschild wormholes were apparent, it was proposed that quasars were white holes forming the ends of wormholes of this type.
While Schwarzschild wormholes are not traversable, their existence inspired Kip Thorne to imagine traversable wormholes created by holding the 'throat' of a Schwarzschild wormhole open with exotic matter (material that has negative mass/energy).
what is Donohue syndrome;explain?
Kevin7
Answer
Donohue syndrome
By Paul A. JohnsonThe Gale Group Inc.
Definition
Donohue syndrome, also formerly called leprechaunism, is a genetic disorder caused by mutations in the insulin receptor gene. W. L. Donohue first described this rare syndrome in 1948.
Description
Donohue syndrome is a disorder that causes low birth weight, unusual facial features, and failure to thrive in infants. Donohue syndrome is associated with the over-development of the pancreas, a gland located near the stomach. It is also considered to be the most insulin resistant form of diabetes.
Donohue syndrome results from a mutation of the insulin receptor gene which prevents insulin in the blood from being processed. Therefore, even before birth, the fetus exhibits "insulin resistance" and has high levels of unprocessed insulin in the blood. Insulin is one of two hormones secreted by the pancreas to control blood sugar (glucose) levels. Donohue syndrome is known as a progressive endocrine disorder because it relates to the growth and functions of the endocrine system, the collection of glands and organs that deliver hormones via the bloodstream.
Hormones are chemicals released by the body to control cellular function (metabolism) and maintain equilibrium (homeostasis). These hormones are released either by the endocrine system or by the exocrine system. The endocrine system consists of ductless glands that secrete hormones into the bloodstream. These hormones then travel through the blood to the parts of the body where they are required. The exocrine system consists of ducted glands that release their hormones via ducts directly to the site where they are needed. The pancreas is both an endocrine and an exocrine gland. As part of the endocrine system, the pancreas acts as the original producer of estrogen and other sex hormones in fetuses of both sexes. It also regulates blood sugar through its production of the hormones insulin and glucagon. The pancreas releases insulin in response to high levels of glucose in the blood. Glucagon is released when glucose levels in the blood are low. These two hormones act in direct opposition to each other (antagonistically) to maintain proper blood sugar levels. As an exocrine gland, the pancreas secretes digestive enzymes directly into the small intestine.
In an attempt to compensate for the high blood insulin level, the pancreas overproduces glucagon as well as the female hormone estrogen and other related (estrogenic) hormones. As excess estrogen and related hormones are produced, they affect the development of the external and internal sex organs (genitalia) of the growing baby.
Insulin mediates the baby's growth in the womb through the addition of muscle and fat. A genetic link between fetal insulin resistance and low birthweight has been suggested. Without the proper processing of insulin, the fetus will not gain weight as fast as expected. Therefore, the effects of Donohue syndrome tend to become visible during the seventh month of development when the fetus either stops growing entirely or shows a noticeable slowdown in size and weight gain. This lack of growth is further evident at birth in affected infants, who demonstrate extreme thinness (emaciation), difficulty gaining weight, a failure to thrive, and delayed maturation of the skeletal structure.
Signs and symptoms
Infants born with Donohue syndrome have characteristic facial features that have been said to exhibit "elfin" or leprechaun-like qualities, such as: a smallish head with large, poorly developed and low-set ears; a flat nasal ridge with flared nostrils, thick lips, a greatly exaggerated mouth width, and widely spaced eyes. They will be very thin and have low blood sugar (hypoglycemia) due to their inability to gain nutrition through insulin processing. They will exhibit delayed bone growth and maturation, and difficulty in gaining weight and developing (failure to thrive).
Donohue syndrome patients are prone to persistent and recurrent infections. Delayed bone growth not only leads to skeletal abnormalities, it also leads to a compromised immune system. Many of the chemicals used by the body to fight infection are produced in the marrow of the bones. When bone maturation is delayed, these chemicals are not produced in sufficient quantities to fight off or prevent infection.
At birth, affected individuals can also have an enlarged chest, with possible breast development, excessive hairiness (hirsutism), as well as overdeveloped external sex organs, because of increased estrogen production caused by an overactive pancreas. As an additional side effect of the increased sex hormones released in Donohue syndrome, these individuals often have extremely large hands and feet relative to their non-affected peer group.
Donohue syndrome
By Paul A. JohnsonThe Gale Group Inc.
Definition
Donohue syndrome, also formerly called leprechaunism, is a genetic disorder caused by mutations in the insulin receptor gene. W. L. Donohue first described this rare syndrome in 1948.
Description
Donohue syndrome is a disorder that causes low birth weight, unusual facial features, and failure to thrive in infants. Donohue syndrome is associated with the over-development of the pancreas, a gland located near the stomach. It is also considered to be the most insulin resistant form of diabetes.
Donohue syndrome results from a mutation of the insulin receptor gene which prevents insulin in the blood from being processed. Therefore, even before birth, the fetus exhibits "insulin resistance" and has high levels of unprocessed insulin in the blood. Insulin is one of two hormones secreted by the pancreas to control blood sugar (glucose) levels. Donohue syndrome is known as a progressive endocrine disorder because it relates to the growth and functions of the endocrine system, the collection of glands and organs that deliver hormones via the bloodstream.
Hormones are chemicals released by the body to control cellular function (metabolism) and maintain equilibrium (homeostasis). These hormones are released either by the endocrine system or by the exocrine system. The endocrine system consists of ductless glands that secrete hormones into the bloodstream. These hormones then travel through the blood to the parts of the body where they are required. The exocrine system consists of ducted glands that release their hormones via ducts directly to the site where they are needed. The pancreas is both an endocrine and an exocrine gland. As part of the endocrine system, the pancreas acts as the original producer of estrogen and other sex hormones in fetuses of both sexes. It also regulates blood sugar through its production of the hormones insulin and glucagon. The pancreas releases insulin in response to high levels of glucose in the blood. Glucagon is released when glucose levels in the blood are low. These two hormones act in direct opposition to each other (antagonistically) to maintain proper blood sugar levels. As an exocrine gland, the pancreas secretes digestive enzymes directly into the small intestine.
In an attempt to compensate for the high blood insulin level, the pancreas overproduces glucagon as well as the female hormone estrogen and other related (estrogenic) hormones. As excess estrogen and related hormones are produced, they affect the development of the external and internal sex organs (genitalia) of the growing baby.
Insulin mediates the baby's growth in the womb through the addition of muscle and fat. A genetic link between fetal insulin resistance and low birthweight has been suggested. Without the proper processing of insulin, the fetus will not gain weight as fast as expected. Therefore, the effects of Donohue syndrome tend to become visible during the seventh month of development when the fetus either stops growing entirely or shows a noticeable slowdown in size and weight gain. This lack of growth is further evident at birth in affected infants, who demonstrate extreme thinness (emaciation), difficulty gaining weight, a failure to thrive, and delayed maturation of the skeletal structure.
Signs and symptoms
Infants born with Donohue syndrome have characteristic facial features that have been said to exhibit "elfin" or leprechaun-like qualities, such as: a smallish head with large, poorly developed and low-set ears; a flat nasal ridge with flared nostrils, thick lips, a greatly exaggerated mouth width, and widely spaced eyes. They will be very thin and have low blood sugar (hypoglycemia) due to their inability to gain nutrition through insulin processing. They will exhibit delayed bone growth and maturation, and difficulty in gaining weight and developing (failure to thrive).
Donohue syndrome patients are prone to persistent and recurrent infections. Delayed bone growth not only leads to skeletal abnormalities, it also leads to a compromised immune system. Many of the chemicals used by the body to fight infection are produced in the marrow of the bones. When bone maturation is delayed, these chemicals are not produced in sufficient quantities to fight off or prevent infection.
At birth, affected individuals can also have an enlarged chest, with possible breast development, excessive hairiness (hirsutism), as well as overdeveloped external sex organs, because of increased estrogen production caused by an overactive pancreas. As an additional side effect of the increased sex hormones released in Donohue syndrome, these individuals often have extremely large hands and feet relative to their non-affected peer group.
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