In the early days of the use of genetic fingerprinting as criminal evidence, juries were often swayed by spurious statistical arguments by defense lawyers along these lines: given a match that had a 1 in 5 million probability of occurring by chance, the lawyer would argue that this meant that in a country of say 60 million people there were 12 people who would also match the profile. This was then translated to a 1 in 12 chance of the suspect being the guilty one. This argument is not sound unless the suspect was drawn at random from the population of the country. In fact, a jury should consider how likely it is that an individual matching the genetic profile would also have been a suspect in the case for other reasons. Another spurious statistical argument is based on the false assumption that a 1 in 5 million probability of a match automatically translates into a 1 in 5 million probability of innocence and is known as the prosecutor's fallacy.
When using RFLP, the theoretical risk of a coincidental match is 1 in 100 billion (100,000,000,000), although the practical risk is actually 1 in 1000 because monozygotic twins are 0.2% of the human population. Moreover, the rate of laboratory error is almost certainly higher than this, and often actual laboratory procedures do not reflect the theory under which the coincidence probabilities were computed. For example, the coincidence probabilities may be calculated based on the probabilities that markers in two samples have bands in precisely the same location, but a laboratory worker may conclude that similar—but not precisely identical—band patterns result from identical genetic samples with some imperfection in the agarose gel. However, in this case, the laboratory worker increases the coincidence risk by expanding the criteria for declaring a match. Recent studies have quoted relatively high error rates which may be cause for concern. In the early days of genetic fingerprinting, the necessary population data to accurately compute a match probability was sometimes unavailable. Between 1992 and 1996, arbitrary low ceilings were controversially put on match probabilities used in RFLP analysis rather than the higher theoretically computed ones. Today, RFLP has become widely disused due to the advent of more discriminating, sensitive and easier technologies.
STRs do not suffer from such subjectivity and provide similar power of discrimination (1 in 10^13 for unrelated individuals if using a full SGM+ profile) It should be noted that figures of this magnitude are not considered to be statistically supportable by scientists in the UK, for unrelated individuals with full matching DNA profiles a match probability of 1 in a billion (one thousand million) is considered statistically supportable (Since 1998 the DNA profiling system supported by The National DNA Database in the UK is the SGM+ DNA profiling system which includes 10 STR regions and a sex indicating test. However, with any DNA technique, the cautious juror should not convict on genetic fingerprint evidence alone if other factors raise doubt. Contamination with other evidence (secondary transfer) is a key source of incorrect DNA profiles and raising doubts as to whether a sample has been adulterated is a favorite defense technique. More rarely, Chimerism is one such instance where the lack of a genetic match may unfairly exclude a suspect.
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Thursday, July 30, 2009
Solar eclipse
A solar eclipse occurs when the moon passes between the Sun and the Earth so that the Sun is fully or partially covered. This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. At least two and up to five solar eclipses can occur each year on Earth, with between zero and two of them being total eclipses.[1] Total solar eclipses are nevertheless rare at any location because during each eclipse totality exists only along a narrow corridor in the relatively tiny area of the Moon's umbra.
A total solar eclipse is a spectacular natural phenomenon and many people travel to remote locations to observe one. The 1999 total eclipse in Europe helped to increase public awareness of the phenomenon, as illustrated by the number of journeys made specifically to witness the 2005 annular eclipse and the 2006 total eclipse. The recent solar eclipse of January 26, 2009 was an annular eclipse (see below), while the solar eclipse of July 22, 2009 was a total solar eclipse.
In ancient times, and in some cultures today, solar eclipses have been attributed to supernatural causes. Total solar eclipses can be frightening for people who are unaware of their astronomical explanation, as the Sun seems to disappear in the middle of the day and the sky darkens in a matter of minutes.
A total solar eclipse is a spectacular natural phenomenon and many people travel to remote locations to observe one. The 1999 total eclipse in Europe helped to increase public awareness of the phenomenon, as illustrated by the number of journeys made specifically to witness the 2005 annular eclipse and the 2006 total eclipse. The recent solar eclipse of January 26, 2009 was an annular eclipse (see below), while the solar eclipse of July 22, 2009 was a total solar eclipse.
In ancient times, and in some cultures today, solar eclipses have been attributed to supernatural causes. Total solar eclipses can be frightening for people who are unaware of their astronomical explanation, as the Sun seems to disappear in the middle of the day and the sky darkens in a matter of minutes.
Human cloning
Human cloning is the creation of a genetically identical copy of an existing or previously existing human. The term is generally used to refer to artificial human cloning; human clones in the form of identical twins are commonplace, with their cloning occurring during the natural process of reproduction. There are two commonly discussed types of human cloning: therapeutic cloning and reproductive cloning. Therapeutic cloning involves cloning cells from an adult for use in medicine and is an active area of research: while reproductive cloning would involve making cloned human beings. Such reproductive cloning has not been performed and is illegal in many countries. A third type of cloning called replacement cloning is a theoretical possibility, and would be a combination of therapeutic and reproductive cloning. Replacement cloning would entail the replacement of an extensively damaged, failed, or failing body through cloning followed by whole or partial brain transplant.
The various forms of human cloning are controversial.There have been numerous demands for all progress in the human cloning field to be halted. Some people and groups oppose therapeutic cloning, but most scientific, governmental and religious organizations oppose reproductive cloning. The American Association for the Advancement of Science (AAAS) and other scientific organizations have made public statements suggesting that human reproductive cloning be banned until safety issues are resolved . Serious ethical concerns have been raised by the idea that it might be possible in the future to harvest organs from clones. Some people have considered the idea of growing organs separately from a human organism - in doing this, a new organ supply could be established without the moral implications of harvesting them from humans. Research is also being done on the idea of growing organs that are biologically acceptable to the human body inside of other organisms, such as pigs or cows, then transplanting them to humans, a form of xenotransplantation.
The first human hybrid human clone was created in November 1998, by American Cell Technologies. It was created from a man's leg cell, and a cow's egg whose DNA was removed. It was destroyed after 12 days. Since a normal embryo implants at 14 days, Dr Robert Lanza, ACT's director of tissue engineering, told the Daily Mail newspaper that the embryo could not be seen as a person before 14 days. While making an embryo, which may have resulted in complete human had it been allowed to come to term, according to ACT: "[ACT's] aim was 'therapeutic cloning' not 'reproductive cloning'"
On January, 2008, Wood and Andrew French, Stemagen's chief scientific officer in California, announced that they successfully created the first 5 mature human embryos using DNA from adult skin cells, aiming to provide a source of viable embryonic stem cells. Dr. Samuel Wood and a colleague donated skin cells, and DNA from those cells was transferred to human eggs. It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The 5 cloned embryos, created in Stemagen Corporation lab, in La Jolla, were destroyed.
The various forms of human cloning are controversial.There have been numerous demands for all progress in the human cloning field to be halted. Some people and groups oppose therapeutic cloning, but most scientific, governmental and religious organizations oppose reproductive cloning. The American Association for the Advancement of Science (AAAS) and other scientific organizations have made public statements suggesting that human reproductive cloning be banned until safety issues are resolved . Serious ethical concerns have been raised by the idea that it might be possible in the future to harvest organs from clones. Some people have considered the idea of growing organs separately from a human organism - in doing this, a new organ supply could be established without the moral implications of harvesting them from humans. Research is also being done on the idea of growing organs that are biologically acceptable to the human body inside of other organisms, such as pigs or cows, then transplanting them to humans, a form of xenotransplantation.
The first human hybrid human clone was created in November 1998, by American Cell Technologies. It was created from a man's leg cell, and a cow's egg whose DNA was removed. It was destroyed after 12 days. Since a normal embryo implants at 14 days, Dr Robert Lanza, ACT's director of tissue engineering, told the Daily Mail newspaper that the embryo could not be seen as a person before 14 days. While making an embryo, which may have resulted in complete human had it been allowed to come to term, according to ACT: "[ACT's] aim was 'therapeutic cloning' not 'reproductive cloning'"
On January, 2008, Wood and Andrew French, Stemagen's chief scientific officer in California, announced that they successfully created the first 5 mature human embryos using DNA from adult skin cells, aiming to provide a source of viable embryonic stem cells. Dr. Samuel Wood and a colleague donated skin cells, and DNA from those cells was transferred to human eggs. It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The 5 cloned embryos, created in Stemagen Corporation lab, in La Jolla, were destroyed.
Liger
The liger is a hybrid cross between a male lion (Panthera leo) and a tigress (Panthera tigris), hence has parents with the same genus but of different species. It is distinct from the similar hybrid tigon. It is the largest of all cats and extant felines.[citation needed]
Ligers borrow positive characteristics from both species. Ligers enjoy swimming which is a characteristic of tigers and are very sociable like lions. However ligers are often faced with a variety of health risks and other issues. Ligers only exist in captivity because lions and tigers live in different regions and would never breed voluntarily in the wild. Ligers are larger than both their parents which is usually dangerous to the pregnant tigress and may make it neccessary for offspring to be delivered via caesarean section. The liger often has a very limited life span as well as birth defects and other mutations.
The history of ligers dates to at least the early 19th century in Asia. In 1799, Geoffrey St Hilaire (1772–1844) made a colour plate of the offspring of a lion and a tiger.
In 1825, G.B. Whittaker made an engraving of liger cubs born in 1824. The parents and their three liger offspring are also depicted with their trainer in a 19th Century painting in the naïve style.
Two liger cubs which had been born in 1837 were exhibited to William IV and to his successor Victoria. On 14 December 1900 and on 31 May 1901, Carl Hagenbeck wrote to zoologist James Cossar Ewart with details and photographs of ligers born at the Hagenbeck's Tierpark in Hamburg in 1897.
In Animal Life and the World of Nature (1902–1903), A.H. Bryden described Hagenbeck's "lion-tiger" hybrids:
It has remained for one of the most enterprising collectors and naturalists of our time, Mr Carl Hagenbeck, not only to breed, but to bring successfully to a healthy maturity, specimens of this rare alliance between those two great and formidable felidae, the lion and tiger. The illustrations will indicate sufficiently how fortunate Mr Hagenbeck has been in his efforts to produce these hybrids. The oldest and biggest of the animals shown is a hybrid born on the 11th May, 1897. This fine beast, now more than five years old, equals and even excels in his proportions a well-grown lion, measuring as he does from nose tip to tail 10 ft 2 inches in length, and standing only three inches less than 4 ft at the shoulder. A good big lion will weigh about 400 lb [...] the hybrid in question, weighing as it does no less than 467 lb, is certainly the superior of the most well-grown lions, whether wild-bred or born in a menagerie. This animal shows faint striping and mottling, and, in its characteristics, exhibits strong traces of both its parents. It has a somewhat lion-like head, and the tail is more like that of a lion than of a tiger. On the other hand, it has no trace of mane. It is a huge and very powerful beast.
In 1935, four ligers from two litters were reared in the Zoological Gardens of Bloemfontein, South Africa. Three of them, a male and two females, were still living in 1953. The male weighed 750 lb. and stood a foot and a half taller than a full grown male lion at the shoulder.
Although ligers are more commonly found than tigons today, in At Home In The Zoo (1961), Gerald Iles wrote "For the record I must say that I have never seen a liger, a hybrid obtained by crossing a lion with a tigress. They seem to be even rarer than tigons."
Ligers borrow positive characteristics from both species. Ligers enjoy swimming which is a characteristic of tigers and are very sociable like lions. However ligers are often faced with a variety of health risks and other issues. Ligers only exist in captivity because lions and tigers live in different regions and would never breed voluntarily in the wild. Ligers are larger than both their parents which is usually dangerous to the pregnant tigress and may make it neccessary for offspring to be delivered via caesarean section. The liger often has a very limited life span as well as birth defects and other mutations.
The history of ligers dates to at least the early 19th century in Asia. In 1799, Geoffrey St Hilaire (1772–1844) made a colour plate of the offspring of a lion and a tiger.
In 1825, G.B. Whittaker made an engraving of liger cubs born in 1824. The parents and their three liger offspring are also depicted with their trainer in a 19th Century painting in the naïve style.
Two liger cubs which had been born in 1837 were exhibited to William IV and to his successor Victoria. On 14 December 1900 and on 31 May 1901, Carl Hagenbeck wrote to zoologist James Cossar Ewart with details and photographs of ligers born at the Hagenbeck's Tierpark in Hamburg in 1897.
In Animal Life and the World of Nature (1902–1903), A.H. Bryden described Hagenbeck's "lion-tiger" hybrids:
It has remained for one of the most enterprising collectors and naturalists of our time, Mr Carl Hagenbeck, not only to breed, but to bring successfully to a healthy maturity, specimens of this rare alliance between those two great and formidable felidae, the lion and tiger. The illustrations will indicate sufficiently how fortunate Mr Hagenbeck has been in his efforts to produce these hybrids. The oldest and biggest of the animals shown is a hybrid born on the 11th May, 1897. This fine beast, now more than five years old, equals and even excels in his proportions a well-grown lion, measuring as he does from nose tip to tail 10 ft 2 inches in length, and standing only three inches less than 4 ft at the shoulder. A good big lion will weigh about 400 lb [...] the hybrid in question, weighing as it does no less than 467 lb, is certainly the superior of the most well-grown lions, whether wild-bred or born in a menagerie. This animal shows faint striping and mottling, and, in its characteristics, exhibits strong traces of both its parents. It has a somewhat lion-like head, and the tail is more like that of a lion than of a tiger. On the other hand, it has no trace of mane. It is a huge and very powerful beast.
In 1935, four ligers from two litters were reared in the Zoological Gardens of Bloemfontein, South Africa. Three of them, a male and two females, were still living in 1953. The male weighed 750 lb. and stood a foot and a half taller than a full grown male lion at the shoulder.
Although ligers are more commonly found than tigons today, in At Home In The Zoo (1961), Gerald Iles wrote "For the record I must say that I have never seen a liger, a hybrid obtained by crossing a lion with a tigress. They seem to be even rarer than tigons."
iPod
iPod is a brand of portable media players designed and marketed by Apple Inc. and launched on October 23, 2001 (2001-10-23). The product line-up includes the hard drive-based iPod Classic, the touchscreen iPod Touch, the video-capable iPod Nano, and the compact iPod Shuffle. The iPhone can function as an iPod but is generally treated as a separate product. Former iPod models include the iPod Mini and the spin-off iPod Photo (since reintegrated into the main iPod Classic line). iPod Classic models store media on an internal hard drive, while all other models use flash memory to enable their smaller size (the discontinued Mini used a Microdrive miniature hard drive). As with many other digital music players, iPods can also serve as external data storage devices. Storage capacity varies by model.
Apple's iTunes software can be used to transfer music to the devices from computers using certain versions of Apple Macintosh and Microsoft Windows operating systems. For users who choose not to use Apple's software or whose computers cannot run iTunes software, several open source alternatives to iTunes are also available. iTunes and its alternatives may also transfer photos, videos, games, contact information, e-mail settings, Web bookmarks, and calendars to iPod models supporting those features. As of September 2008[update], more than 173,000,000 iPods had been sold worldwide, making it the best-selling digital audio player series in history.
Apple's iTunes software can be used to transfer music to the devices from computers using certain versions of Apple Macintosh and Microsoft Windows operating systems. For users who choose not to use Apple's software or whose computers cannot run iTunes software, several open source alternatives to iTunes are also available. iTunes and its alternatives may also transfer photos, videos, games, contact information, e-mail settings, Web bookmarks, and calendars to iPod models supporting those features. As of September 2008[update], more than 173,000,000 iPods had been sold worldwide, making it the best-selling digital audio player series in history.
Human genetic variation
Human genetic variation is the genetic diversity of humans and represents the total amount of genetic characteristics observed within the human species. Genetic differences are observed between humans at both the individual and the population level. There may be multiple variants of any given gene in the human population (alleles), leading to polymorphism. Many genes are not polymorphic, meaning that only a single allele is present in the population: that allele is then said to be fixed. [1] No two humans are genetically identical, even monozygotic twins, who develop from a single zygote, have infrequent genetic differences due to mutations occurring during development and gene copy number variation has been observed.[2] Differences between individuals, even closely related individuals, are the key to techniques such as genetic fingerprinting. Alleles occur at different frequencies in different human populations, with populations that are more geographically and ancestrally remote tending to differ more.
Causes of differences between individuals include the exchange of genes during meiosis and various mutational events. There are at least two reasons why genetic variation exists between populations. Natural selection may confer an adaptive advantage to individuals in a specific environment if an allele provides a competitive advantage. Alleles under selection are likely to occur only in those geographic regions where they confer an advantage. The second main cause of genetic variation is due to the high degree of neutrality of most mutations. Most mutations do not appear to have any selective effect one way or the other on the organism. The main cause is genetic drift, this is the effect of random changes in the gene pool. In humans, founder effect and past small population size (increasing the likelihood of genetic drift) may have had an important influence in neutral differences between populations. The theory that humans recently migrated out of Africa, is sometimes given as an example of this. It has been theorised that the migration out of Africa only represented a small fraction of the genetic variation in Africa and that this is a contibuting cause of the observed lower levels of diversity in all indigenous humans outside of Africa. Generally, more recent neutral polymorphisms caused by mutation are likely to be relatively geographically localised and rare, while older polymorphisms are more likely to be shared by a wider range of human groups. The large majority of observed genetic variation occurs within a population in any geographic region and not between populations in different regions, although it is still usually possible to accurately identify the geographic origins of any individual's ancestors by genetic means.
The study of human genetic variation has both evolutionary significance and medical applications. The study can help scientists understand ancient human population migrations as well as how different human groups are biologically related to one another. From a medical perspective the study of human genetic variation may be important because some disease causing alleles occur at a greater frequency in people from specific geographic regions.
Causes of differences between individuals include the exchange of genes during meiosis and various mutational events. There are at least two reasons why genetic variation exists between populations. Natural selection may confer an adaptive advantage to individuals in a specific environment if an allele provides a competitive advantage. Alleles under selection are likely to occur only in those geographic regions where they confer an advantage. The second main cause of genetic variation is due to the high degree of neutrality of most mutations. Most mutations do not appear to have any selective effect one way or the other on the organism. The main cause is genetic drift, this is the effect of random changes in the gene pool. In humans, founder effect and past small population size (increasing the likelihood of genetic drift) may have had an important influence in neutral differences between populations. The theory that humans recently migrated out of Africa, is sometimes given as an example of this. It has been theorised that the migration out of Africa only represented a small fraction of the genetic variation in Africa and that this is a contibuting cause of the observed lower levels of diversity in all indigenous humans outside of Africa. Generally, more recent neutral polymorphisms caused by mutation are likely to be relatively geographically localised and rare, while older polymorphisms are more likely to be shared by a wider range of human groups. The large majority of observed genetic variation occurs within a population in any geographic region and not between populations in different regions, although it is still usually possible to accurately identify the geographic origins of any individual's ancestors by genetic means.
The study of human genetic variation has both evolutionary significance and medical applications. The study can help scientists understand ancient human population migrations as well as how different human groups are biologically related to one another. From a medical perspective the study of human genetic variation may be important because some disease causing alleles occur at a greater frequency in people from specific geographic regions.
Accuracy of early rockets
William Congreve, son of the Comptroller of the Royal Arsenal, Woolwich, London, became a major figure in the field. From 1801, Congreve set on a vigorous research and development program at the Arsenal's laboratory.[14] Congreve prepared a new propellant mixture, and developed a rocket motor with a strong iron tube with conical nose. This early Congreve rocket weighed about 32 pounds (14.5 kilograms). The Royal Arsenal's first demonstration of solid fuel rockets was in 1805. The rockets were effectively used during the Napoleonic Wars and the War of 1812. Congreve published three books on rocketry.
From there, the use of military rockets spread throughout Europe. At the Battle of Baltimore in 1814, the rockets fired on Fort McHenry by the rocket vessel HMS Erebus were the source of the rockets' red glare described by Francis Scott Key in The Star-Spangled Banner. Rockets were also used in the Battle of Waterloo.
Early rockets were very inaccurate. Without the use of spinning or any gimballing of the thrust, they had a strong tendency to veer sharply off course. The early British Congreve rockets[14] reduced this somewhat by attaching a long stick to the end of a rocket (similar to modern bottle rockets) to make it harder for the rocket to change course. The largest of the Congreve rockets was the 32-pound (14.5 kg) Carcass, which had a 15-foot (4.6 m) stick. Originally, sticks were mounted on the side, but this was later changed to mounting in the center of the rocket, reducing drag and enabling the rocket to be more accurately fired from a segment of pipe.
The accuracy problem was greatly improved in 1844 when William Hale modified the rocket design so that thrust was slightly vectored, causing the rocket to spin along its axis of travel like a bullet. The Hale rocket removed the need for a rocket stick, travelled further due to reduced air resistance, and was far more accurate.
Tuesday, July 21, 2009
Introduction to Unified Field Theory
In physics, a unified field theory is a type of field theory that allows all of the fundamental forces between elementary particles to be written in terms of a single field. There is no accepted unified field theory yet, and this remains an open line of research. The term was coined by Albert Einstein who attempted to unify the general theory of relativity with electromagnetism. A Theory of Everything is closely related to unified field theory, but differs by not requiring the basis of nature to be fields, and also attempts to explain all physical constants of nature.
This article describes unified field theory as it is currently understood in connection with quantum theory. Earlier attempts based on classical physics are described in the article on classical unified field theories.
There may be no a priori reason why the correct description of nature has to be a unified field theory; however, this goal has led to a great deal of progress in modern theoretical physics and continues to motivate research. Unified field theory is only one possible approach to unification of physics.
According to the current understanding of physics, forces between objects (e.g. gravitation) are not transmitted directly between the two objects, but instead go through intermediary entities called fields. All four of the known fundamental forces are mediated by fields, which in the Standard Model of particle physics result from exchange of bosons (integral-spin particles). Specifically the four interactions to be unified are (from strongest to weakest):
Strong nuclear interaction: the interaction responsible for holding quarks together to form neutrons and protons, and holding neutrons and protons together to form nuclei. The exchange particle that mediates this force is the gluon.
Electromagnetic interaction: the familiar interaction that acts on electrically charged particles. The photon is the exchange particle for this force.
Weak nuclear interaction: a repulsive short-range interaction responsible for radioactivity, that acts on electrons, neutrinos and quarks. It is governed by the W and Z bosons.
Gravitational interaction: a long-range attractive interaction that acts on all particles with mass. The postulated exchange particle has been named the graviton.
Modern unified field theory attempts to bring these four force-mediating fields together into a single framework. Quantum theory seems to limit any deterministic theory's descriptive power (in simple terms, no theory can predict events more accurately than allowed by the Planck constant).
This article describes unified field theory as it is currently understood in connection with quantum theory. Earlier attempts based on classical physics are described in the article on classical unified field theories.
There may be no a priori reason why the correct description of nature has to be a unified field theory; however, this goal has led to a great deal of progress in modern theoretical physics and continues to motivate research. Unified field theory is only one possible approach to unification of physics.
According to the current understanding of physics, forces between objects (e.g. gravitation) are not transmitted directly between the two objects, but instead go through intermediary entities called fields. All four of the known fundamental forces are mediated by fields, which in the Standard Model of particle physics result from exchange of bosons (integral-spin particles). Specifically the four interactions to be unified are (from strongest to weakest):
Strong nuclear interaction: the interaction responsible for holding quarks together to form neutrons and protons, and holding neutrons and protons together to form nuclei. The exchange particle that mediates this force is the gluon.
Electromagnetic interaction: the familiar interaction that acts on electrically charged particles. The photon is the exchange particle for this force.
Weak nuclear interaction: a repulsive short-range interaction responsible for radioactivity, that acts on electrons, neutrinos and quarks. It is governed by the W and Z bosons.
Gravitational interaction: a long-range attractive interaction that acts on all particles with mass. The postulated exchange particle has been named the graviton.
Modern unified field theory attempts to bring these four force-mediating fields together into a single framework. Quantum theory seems to limit any deterministic theory's descriptive power (in simple terms, no theory can predict events more accurately than allowed by the Planck constant).
Cosmetic Surgery
Cosmetic or Aesthetic Surgery involves techniques intended for the enhancement of appearance through surgical and medical techniques, and is specifically concerned with maintaining normal appearance, restoring it, or enhancing it beyond the average level toward some aesthetic ideal.
In 2006, nearly 11 million cosmetic surgeries were performed in the United States alone. The number of cosmetic sprocedures performed in the United States has increased over 50 percent since the start of the century. Nearly 12 million cosmetic surgeries were performed in 2007, with the five most common being breast augmentation, liposuction, nasal surgery, eyelid surgery and abdominoplasty. The increased use of cosmetic surgery crosses racial and ethnic lines in the U.S., with increases seen among African-Americans and Hispanic Americans as well as Caucasian Americans. In Europe, the second largest market for cosmetic procedures, cosmetic surgery is a $2.2 billion business.
The most prevalent aesthetic/cosmetic procedures are listed below. Most of these types of surgery are more commonly known by their "common names." These are also listed when pertinent.
Abdominoplasty (or "tummy tuck"): reshaping and firming of the abdomen
Blepharoplasty (or "eyelid surgery"): Reshaping of the eyelids or the application of permanent eyeliner, including Asian blepharoplasty
Mammoplasty
Breast augmentation ("breast enlargement" or "boob job"): Augmentation of the breasts. This can involve either fat grafting, saline or silicone gel prosthetics. Initially performed to women with micromastia
Breast reduction: Removal of skin and glandular tissue. Indicated to reduce back and shoulder pain in women with gigantomastia and/or for psychological benefit in women with gigantomastia/macromastia and men with gynecomastia.
Breast lift (Mastopexy): Lifting or reshaping of breasts to make them less saggy, often after weight loss (after a pregnancy, for example). It involves removal of breast skin as opposed to glandular tissue or scarless suture technique
Buttock Augmentation (or "butt augmentation" or "butt implants"): Enhancement of the buttocks. This procedure can be performed by using silicone implants or fat grafting and transfer from other areas of the body.
Buttock lift (or "butt lift" or "brazilian butt lift"): Lifting, projection, tightening of the buttocks. This procedure can be performed by using the scarless suture technique without implants. [10]
Chemical peel: Minimizing the appearance of acne, pock, and other scars as well as wrinkles (depending on concentration and type of agent used, except for deep furrows), solar lentigines (age spots, freckles), and photodamage in general. Chemical peels commonly involve carbolic acid (Phenol), trichloroacetic acid (TCA), glycolic acid (AHA), or salicylic acid (BHA) as the active agent.
Labiaplasty: Surgical reduction and reshaping of the labia
Rhinoplasty (or "nose job"): Reshaping of the nose
Otoplasty (or ear surgery): Reshaping of the ear. Most often done by pinning the ear closer to the head.
Rhytidectomy (or "face lift"): Removal of wrinkles and signs of aging from the face
Suction-Assisted Lipectomy (or liposuction): Removal of fat from the body
Brow lift: higher brow position by surgical or scarless suture
Chin augmentation: Augmentation of the chin with an implant (e.g. silicone) by sliding genioplasty of the jawbone or by suture of the soft tissue.
Cheek augmentation
Cheek lift/Midface lift using scarless suture technique.
Collagen, fat, and other tissue filler injections (e.g. hyaluronic acid)
Laser skin resurfacing
Hilotherapy a therapy that provides relief from heamatoma, pain and swelling post-surgery without the dangers of Frostbite and Skin Necrosis
In 2006, nearly 11 million cosmetic surgeries were performed in the United States alone. The number of cosmetic sprocedures performed in the United States has increased over 50 percent since the start of the century. Nearly 12 million cosmetic surgeries were performed in 2007, with the five most common being breast augmentation, liposuction, nasal surgery, eyelid surgery and abdominoplasty. The increased use of cosmetic surgery crosses racial and ethnic lines in the U.S., with increases seen among African-Americans and Hispanic Americans as well as Caucasian Americans. In Europe, the second largest market for cosmetic procedures, cosmetic surgery is a $2.2 billion business.
The most prevalent aesthetic/cosmetic procedures are listed below. Most of these types of surgery are more commonly known by their "common names." These are also listed when pertinent.
Abdominoplasty (or "tummy tuck"): reshaping and firming of the abdomen
Blepharoplasty (or "eyelid surgery"): Reshaping of the eyelids or the application of permanent eyeliner, including Asian blepharoplasty
Mammoplasty
Breast augmentation ("breast enlargement" or "boob job"): Augmentation of the breasts. This can involve either fat grafting, saline or silicone gel prosthetics. Initially performed to women with micromastia
Breast reduction: Removal of skin and glandular tissue. Indicated to reduce back and shoulder pain in women with gigantomastia and/or for psychological benefit in women with gigantomastia/macromastia and men with gynecomastia.
Breast lift (Mastopexy): Lifting or reshaping of breasts to make them less saggy, often after weight loss (after a pregnancy, for example). It involves removal of breast skin as opposed to glandular tissue or scarless suture technique
Buttock Augmentation (or "butt augmentation" or "butt implants"): Enhancement of the buttocks. This procedure can be performed by using silicone implants or fat grafting and transfer from other areas of the body.
Buttock lift (or "butt lift" or "brazilian butt lift"): Lifting, projection, tightening of the buttocks. This procedure can be performed by using the scarless suture technique without implants. [10]
Chemical peel: Minimizing the appearance of acne, pock, and other scars as well as wrinkles (depending on concentration and type of agent used, except for deep furrows), solar lentigines (age spots, freckles), and photodamage in general. Chemical peels commonly involve carbolic acid (Phenol), trichloroacetic acid (TCA), glycolic acid (AHA), or salicylic acid (BHA) as the active agent.
Labiaplasty: Surgical reduction and reshaping of the labia
Rhinoplasty (or "nose job"): Reshaping of the nose
Otoplasty (or ear surgery): Reshaping of the ear. Most often done by pinning the ear closer to the head.
Rhytidectomy (or "face lift"): Removal of wrinkles and signs of aging from the face
Suction-Assisted Lipectomy (or liposuction): Removal of fat from the body
Brow lift: higher brow position by surgical or scarless suture
Chin augmentation: Augmentation of the chin with an implant (e.g. silicone) by sliding genioplasty of the jawbone or by suture of the soft tissue.
Cheek augmentation
Cheek lift/Midface lift using scarless suture technique.
Collagen, fat, and other tissue filler injections (e.g. hyaluronic acid)
Laser skin resurfacing
Hilotherapy a therapy that provides relief from heamatoma, pain and swelling post-surgery without the dangers of Frostbite and Skin Necrosis
Thursday, July 16, 2009
Global Positioning System
The Global Positioning System (GPS) is a global navigation satellite system (GNSS) developed by the United States Department of Defense and managed by the United States Air Force 50th Space Wing. It is the only fully functional GNSS in the world, can be used freely by anyone, anywhere, and is often used by civilians for navigation purposes. It uses a constellation of between 24 and 32 medium Earth orbit satellites that transmit precise radiowave signals, which allow GPS receivers to determine their current location, the time, and their velocity. Its official name is NAVSTAR GPS. Although NAVSTAR is not an acronym, a few backronyms have been created for it.
Since it became fully operational on April 27, 1995, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, tracking and surveillance, and hobbies such as geocaching. Also, the precise time reference is used in many applications including the scientific study of earthquakes and as a required time synchronization method for cellular network protocols such as the IS-95 standard for CDMA.
A GPS receiver calculates its position by precisely timing the signals sent by the GPS satellites high above the Earth. Each satellite continually transmits messages containing the time the message was sent, precise orbital information (the ephemeris), and the general system health and rough orbits of all GPS satellites (the almanac). The receiver measures the transit time of each message and computes the distance to each satellite. Geometric trilateration is used to combine these distances with the location of the satellites to determine the receiver's location. The position is displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units also show derived information such as direction and speed, calculated from position changes.
It might seem three satellites are enough to solve for position, since space has three dimensions. However, even a very small clock error multiplied by the very large speed of light—the speed at which satellite signals propagate—results in a large positional error. Therefore receivers use four or more satellites to solve for x, y, z, and t, which is used to correct the receiver's clock. While most GPS applications use the computed location only and effectively hide the very accurately computed time, it is used in a few specialized GPS applications such as time transfer, traffic signal timing, and synchronization of cell phone base stations.
Although four satellites are required for normal operation, fewer apply in special cases. If one variable is already known (for example, a ship or plane may have known elevation), a receiver can determine its position using only three satellites. Some GPS receivers may use additional clues or assumptions (such as reusing the last known altitude, dead reckoning, inertial navigation, or including information from the vehicle computer) to give a degraded position when fewer than four satellites are visible.
Since it became fully operational on April 27, 1995, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, tracking and surveillance, and hobbies such as geocaching. Also, the precise time reference is used in many applications including the scientific study of earthquakes and as a required time synchronization method for cellular network protocols such as the IS-95 standard for CDMA.
A GPS receiver calculates its position by precisely timing the signals sent by the GPS satellites high above the Earth. Each satellite continually transmits messages containing the time the message was sent, precise orbital information (the ephemeris), and the general system health and rough orbits of all GPS satellites (the almanac). The receiver measures the transit time of each message and computes the distance to each satellite. Geometric trilateration is used to combine these distances with the location of the satellites to determine the receiver's location. The position is displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units also show derived information such as direction and speed, calculated from position changes.
It might seem three satellites are enough to solve for position, since space has three dimensions. However, even a very small clock error multiplied by the very large speed of light—the speed at which satellite signals propagate—results in a large positional error. Therefore receivers use four or more satellites to solve for x, y, z, and t, which is used to correct the receiver's clock. While most GPS applications use the computed location only and effectively hide the very accurately computed time, it is used in a few specialized GPS applications such as time transfer, traffic signal timing, and synchronization of cell phone base stations.
Although four satellites are required for normal operation, fewer apply in special cases. If one variable is already known (for example, a ship or plane may have known elevation), a receiver can determine its position using only three satellites. Some GPS receivers may use additional clues or assumptions (such as reusing the last known altitude, dead reckoning, inertial navigation, or including information from the vehicle computer) to give a degraded position when fewer than four satellites are visible.
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion comparable to the detonation of more than a billion kilograms of conventional high explosive.[1] Even small nuclear devices can devastate a city. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major aspect of international policy since their debut.
In the history of warfare, only two nuclear weapons have been detonated offensively, both near the end of World War II. The first was detonated on the morning of 6 August 1945, when the United States dropped a uranium gun-type device code-named "Little Boy" on the Japanese city of Hiroshima. The second was detonated three days later when the United States dropped a plutonium implosion-type device code-named "Fat Man" on the city of Nagasaki, Japan. These bombings resulted in the immediate deaths of around 120,000 people (mostly civilians) from injuries sustained from the explosion and acute radiation sickness, and even more deaths from long-term effects of ionizing radiation. The use of these weapons was and remains controversial. (See atomic bombings of Hiroshima and Nagasaki for a full discussion.)
Since the Hiroshima and Nagasaki bombings, nuclear weapons have been detonated on over two thousand occasions for testing purposes and demonstration purposes. The only countries known to have detonated nuclear weapons—and that acknowledge possessing such weapons—are (chronologically) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, the People's Republic of China, India, Pakistan, and North Korea. Israel is also widely believed to possess nuclear weapons, though it does not acknowledge having them. (For more information on these states' nuclear programs, as well as other states that formerly possessed nuclear weapons or are suspected of seeking nuclear weapons, see list of states with nuclear weapons.)
In the history of warfare, only two nuclear weapons have been detonated offensively, both near the end of World War II. The first was detonated on the morning of 6 August 1945, when the United States dropped a uranium gun-type device code-named "Little Boy" on the Japanese city of Hiroshima. The second was detonated three days later when the United States dropped a plutonium implosion-type device code-named "Fat Man" on the city of Nagasaki, Japan. These bombings resulted in the immediate deaths of around 120,000 people (mostly civilians) from injuries sustained from the explosion and acute radiation sickness, and even more deaths from long-term effects of ionizing radiation. The use of these weapons was and remains controversial. (See atomic bombings of Hiroshima and Nagasaki for a full discussion.)
Since the Hiroshima and Nagasaki bombings, nuclear weapons have been detonated on over two thousand occasions for testing purposes and demonstration purposes. The only countries known to have detonated nuclear weapons—and that acknowledge possessing such weapons—are (chronologically) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, the People's Republic of China, India, Pakistan, and North Korea. Israel is also widely believed to possess nuclear weapons, though it does not acknowledge having them. (For more information on these states' nuclear programs, as well as other states that formerly possessed nuclear weapons or are suspected of seeking nuclear weapons, see list of states with nuclear weapons.)
Swine flu
"Swine flu" or the "H1N1" flu virus (a more technical name for the same virus) is a public health emergency that the U.S. government is keeping a close watch on so that people aware, informed and prepared to take action steps to keep themselves and their families healthy and safe.
Any flu virus is particularly life-threatening to the very young, elderly and those battling disease, infection, etc. There are 5,469 people in the U.S. who have been sickened by the swine influenza and there has been six death so far, according to the Centers for Disease Control and Prevention (CDC). It's important that we keep this virus in check.
Take time to review the CDC's five, flu-safety tips, which will help you avoid swine flu (or any flu). They'll also help to ensure that the virus doesn't spread needlessly.
Tip #1: Stay home if you're sick.
Tip #2: Avoid close contact with people who are sick.
Tip #3: Wash your hands often and avoid touching your eyes, nose and mouth.
Tip #4: Cover your mouth or nose with a tissue when coughing or sneezing.
Tip #5: Keep up with health information in your own community.
Do these tips sound familiar? Flu-safety basics are the exact same whether you get the human flu or the swine flu. The swine flu is a respiratory disease of pigs caused by type A influenza viruses that cause regular outbreaks in pigs. People don’t usually get swine flu but infections can and do occur.
This virus spreads the exact same way that regular flu viruses spread -- person-to-person transmission through coughing, sneezing and touching of infected people or surfaces: door knobs, shopping carts, countertops, etc. So, it’s also a good idea to carry your alcohol-based, disinfecting wipes, sprays and gels with you, as well.
There is some good news: First, there are antiviral medicines to prevent and treat swine flu. They may also prevent serious flu complications. Second, swine influenza viruses are not spread by food. So, you don’t need to throw away or stop eating your pork or pork products. Eating properly handled and cooked pork products is still safe.
Now, if you live in areas where swine influenza have been identified (there are 48 affected states), contact a health care provider, particularly if you are worried about your symptoms. The influenza-like symptoms include: fever, body aches, runny nose, sore throat, nausea, vomiting or diarrhea. Your health care provider will determine whether influenza testing or treatment is needed.
By practicing these flu-safety basics, you’ll lower your chances of getting a host of illnesses, including the swine flu.
Any flu virus is particularly life-threatening to the very young, elderly and those battling disease, infection, etc. There are 5,469 people in the U.S. who have been sickened by the swine influenza and there has been six death so far, according to the Centers for Disease Control and Prevention (CDC). It's important that we keep this virus in check.
Take time to review the CDC's five, flu-safety tips, which will help you avoid swine flu (or any flu). They'll also help to ensure that the virus doesn't spread needlessly.
Tip #1: Stay home if you're sick.
Tip #2: Avoid close contact with people who are sick.
Tip #3: Wash your hands often and avoid touching your eyes, nose and mouth.
Tip #4: Cover your mouth or nose with a tissue when coughing or sneezing.
Tip #5: Keep up with health information in your own community.
Do these tips sound familiar? Flu-safety basics are the exact same whether you get the human flu or the swine flu. The swine flu is a respiratory disease of pigs caused by type A influenza viruses that cause regular outbreaks in pigs. People don’t usually get swine flu but infections can and do occur.
This virus spreads the exact same way that regular flu viruses spread -- person-to-person transmission through coughing, sneezing and touching of infected people or surfaces: door knobs, shopping carts, countertops, etc. So, it’s also a good idea to carry your alcohol-based, disinfecting wipes, sprays and gels with you, as well.
There is some good news: First, there are antiviral medicines to prevent and treat swine flu. They may also prevent serious flu complications. Second, swine influenza viruses are not spread by food. So, you don’t need to throw away or stop eating your pork or pork products. Eating properly handled and cooked pork products is still safe.
Now, if you live in areas where swine influenza have been identified (there are 48 affected states), contact a health care provider, particularly if you are worried about your symptoms. The influenza-like symptoms include: fever, body aches, runny nose, sore throat, nausea, vomiting or diarrhea. Your health care provider will determine whether influenza testing or treatment is needed.
By practicing these flu-safety basics, you’ll lower your chances of getting a host of illnesses, including the swine flu.
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