Saturday, April 24, 2010

Ibn Khaldun

Ibn Khaldūn or Ibn Khaldoun (full name, Arabic: أبو زيد عبد الرحمن بن محمد بن خلدون الحضرمي ‎, Abū Zayd ‘Abdu r-Raḥman bin Muḥammad bin Khaldūn Al-Hadrami, (May 27, 1332 AD/732 AH – March 19, 1406 AD/808 AH) was an Arab polymathan astronomer, economist, historian, Islamic jurist, Islamic lawyer, Islamic scholar, Islamic theologian, hafiz, mathematician, military strategist, nutritionist, philosopher, social scientist and statesman—born in North Africa in present-day Tunisia. He is considered a forerunner of several social scientific disciplines: demography, cultural history, historiography, the philosophy of history, and sociology. He is also considered one of the forerunners of modern economics, alongside the earlier Indian scholar Chanakya. Ibn Khaldun is considered by many to be the father of a number of these disciplines, and of social sciences in general, for anticipating many elements of these disciplines centuries before they were founded in the West. He is best known for his Muqaddimah (known as Prolegomenon in English), the first volume of his book on universal history, Kitab al-Ibar.

Works
Ibn Khaldūn has left behind few works other than his history of the world, al-Kitābu l-ʕibār. Significantly, such writings are not alluded to in his autobiography, suggesting perhaps that Ibn Khaldūn saw himself first and foremost as a historian and wanted to be known above all as the author of al-Kitābu l-ʕibār. From other sources we know of several other works, primarily composed during the time he spent in North Africa and Al-Andalus. His first book, Lubābu l-Muhassal, a commentary on the Islamic theology of Fakhr al-Din al-Razi, was written at the age of 19 under the supervision of his teacher al-Ābilī in Tunis. A work on Sufism, Sifā'u l-Sā'il, was composed around 1373 in Fes, Morocco. Whilst at the court of Muhammed V, Sultan of Granada, Ibn Khaldūn composed a work on logic, ʕallaqa li-l-Sultān.
The Kitābu l-ʕibār (full title: Kitābu l-ʕibār wa Diwānu l-Mubtada' wa l-Ħabar fī Ayyāmu l-ʕarab wa l-Ājam wa l-Barbar wa man ʕĀsarahum min ĐawIu s-Sultānu l-Akbār "Book of Evidence, Record of Beginnings and Events from the Days of the Arabs, Persians and Berbers and their Powerful Contemporaries"), Ibn Khaldūn's main work, was originally conceived as a history of the Berbers. Later, the focus was widened so that in its final form (including its own methodology and anthropology), to represent a so-called "universal history". It is divided into seven books, the first of which, the Muqaddimah, can be considered a separate work. Books two to five cover the history of mankind up to the time of Ibn Khaldūn. Books six and seven cover the history of the Berber peoples and the Maghreb, which remain invaluable to present-day historians, as they are based on Ibn Khaldūn's personal knowledge of the Berbers.
Concerning the discipline of sociology, he conceived a theory of social conflict. He developed the dichotomy of sedentary life versus nomadic life as well as the concept of a "generation," and the inevitable loss of power that occurs when desert warriors conquer a city. Following a contemporary Arab scholar, Sati' al-Husri, the Muqaddimah may be read as a sociological work: six books of general sociology. Topics dealt with in this work include politics, urban life, economics, and knowledge. The work is based around Ibn Khaldun's central concept of 'asabiyyah, which has been translated as "social cohesion", "group solidarity", or "tribalism." This social cohesion arises spontaneously in tribes and other small kinship groups; it can be intensified and enlarged by a religious ideology. Ibn Khaldun's analysis looks at how this cohesion carries groups to power but contains within itself the seeds - psychological, sociological, economic, political - of the group's downfall, to be replaced by a new group, dynasty or empire bound by a stronger (or at least younger and more vigorous) cohesion. Ibn Khaldun has been cited as a racist, but his theories on the rise and fall of empires had no racial component, and this reading of his work has been claimed to be the result of mistranslations.
Perhaps the most frequently cited observation drawn from Ibn Khaldūn's work is the notion that when a society becomes a great civilization (and, presumably, the dominant culture in its region), its high point is followed by a period of decay. This means that the next cohesive group that conquers the diminished civilization is, by comparison, a group of barbarians. Once the barbarians solidify their control over the conquered society, however, they become attracted to its more refined aspects, such as literacy and arts, and either assimilate into or appropriate such cultural practices. Then, eventually, the former barbarians will be conquered by a new set of barbarians, who will repeat the process. Some contemporary readers of Khaldun have read this as an early business cycle theory, though set in the historical circumstances of the mature Islamic empire.
Some readings posit an anticipation of Marx's labour theory of value in Ibn Khaldun's work. Ibn Khaldun asserts that all value (profit) comes from labour, as Marx was later to write. He outlines an early (possibly even the earliest) example of political economy. He describes the economy as being composed of value-adding processes; that is, labour is added to techniques and crafts and the product is sold at a higher value. He also made the distinction between "profit" and "sustenance", in modern political economy terms, surplus and that required for the reproduction of classes respectively. He also calls for the creation of a science to explain society and goes on to outline these ideas in his major work the Muqaddimah

Legacy
Ibn Khaldun was first brought to the attention of the Western world in 1697, when a biography of him appeared in Barthélemy d'Herbelot de Molainville's Bibliothèque Orientale. Ibn Khaldun began gaining more attention from 1806, when Silvestre de Sacy's Chrestomathie Arabe included his biography together with a translation of parts of the Muqaddimah as the Prolegomena. In 1816, de Sacy again published a biography with a more detailed description on the Prolegomena. More details on and partial translations of the Prolegomena emerged over the years until the complete Arabic edition was published in 1858, followed by a complete French translation a few years later by de Sacy. Since then, the work of Ibn Khaldun has been extensively studied in the Western world with special interest.
a) British historian Arnold J. Toynbee called the Muqaddimah "a philosophy of history which is undoubtedly the greatest work of its kind that has ever yet been created by any mind in any time or place." Much of his own work on world history was inspired by Ibn Khaldun.
b) The British philosopher Robert Flint wrote the following on Ibn Khaldun: "As a theorist on history he had no equal in any age… Plato, Aristotle and Augustine were not his peers."
c) Abderrahmane Lakhsassi writes: "No historian of the Maghreb since and particularly of the Berbers can do without his historical contribution."
d) The British philosopher-anthropologist Ernest Gellner considered Ibn Khaldun's definition of government, "an institution which prevents injustice other than such as it commits itself", the best in the history of political theory.
e) Egon Orowan, who termed the concept of socionomy, developed the writings of Ibn Khaldun to forecast an eventual failure of market demand.
f) Arthur Laffer, whom the Laffer curve is named after, noted that, among others, some of Ibn Khaldun's ideas precede his own.
g) In 2006, the Atlas Economic Research Foundation launched an annual essay contest for Muslim students named in Ibn Khaldun's honor. The theme of the contest is "how individuals, think tanks, universities and entrepreneurs can influence government policies to allow the free market to flourish and improve the lives of its citizens based on Islamic teachings and traditions."
h) In 2006, Spain commemorated the 600th anniversary of the death of Ibn Khaldun.

Monday, April 19, 2010

Coral

Corals are marine organisms in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans, which secrete calcium carbonate to form a hard skeleton.
A coral "head," which appears to be a single organism, is a colony of myriad genetically identical polyps. Each polyp is typically only a few millimeters in diameter. Over many generations the colony secretes a skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of individual polyps. Corals also breed sexually by spawning. Polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.
Although corals can catch small fish and animals such as plankton using stinging cells on their tentacles, most corals obtain most of their energy and nutrients from photosynthetic unicellular algae called zooxanthellae. Such corals require sunlight and grow in clear, shallow water, typically at depths shallower than 60 metres (200 ft). Corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not have associated algae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres (9,800 ft). Examples live on the Darwin Mounds located north-west of Cape Wrath, Scotland. Corals coordinate behavior by communicating with each other.

Taxonomy
Corals divide into two subclasses, depending on the number of tentacles or lines of symmetry, and a series of orders corresponding to their exoskeleton, nematocyst type and mitochondrial genetic analysis. Those with eight tentacles are called octocorallia or Alcyonaria and comprise soft corals, sea fans and sea pens. Those with more than eight in a multiple of six are called hexacorallia or Zoantharia. This group includes reef-building corals (Scleractinians), sea anemones and zoanthids.

Anatomy
Initially believed to be a plant, William Herschel used a microscope to establish in the 18th Century that Coral had the characteristic thin cell membranes of an animal.
While a coral head appears to be a single organism, it is actually a group of many individual, yet genetically identical, polyps. The polyps are multicellular organisms. Polyps are usually a few millimeters in diameter, and are formed by a layer of outer epithelium and inner jellylike tissue known as the mesoglea. They are radially symmetrical with tentacles surrounding a central mouth, the only opening to the stomach or coelenteron, through which food is ingested and waste expelled.
The stomach closes at the base of the polyp, where the epithelium produces an exoskeleton called the basal plate or calicle (L. small cup). The calicle is formed by a thickened calcareous ring (annular thickening) with six supporting radial ridges. These structures grow vertically and project into the base of the polyp. When a polyp is physically stressed, its tentacles contract into the calyx so that virtually no part is exposed above the skeletal platform. This protects the organism from predators and the elements.
The polyp grows by extension of vertical calices which occasionally septate to form a new, higher, basal plate. Over many generations this extension forms the large calcareous structures of corals and ultimately coral reefs.
Formation of the calcareous exoskeleton involves deposition of the mineral aragonite by the polyps from calcium and carbonate ions they acquire from seawater. The rate of deposition, while varying greatly across species and environmental conditions, can be as much as 10 g / m² of polyp / day (0.3 ounce / sq yd / day). This is light dependent, with night-time production 90% lower than that during the middle of the day.
Nematocysts are stinging cells at the tips of the calices that carry poison which they rapidly release in response to contact with another organism. The tentacles also bear a contractile band of epithelium called the pharynx. Jellyfish and sea anemones also carry nematocysts.
The polyps interconnect by a complex and well developed system of gastrovascular canals allowing significant sharing of nutrients and symbiotes. In soft corals these range in size from 50–500 micrometres (0.0020–0.020 in) in diameter and allow transport of both metabolites and cellular components.
Many corals as well as other cnidarian groups such as sea anemones (e.g. Aiptasia), form a symbiotic relationship with a class of algae, zooxanthellae, of the genus Symbiodinium. Aiptasia, while considered a pest among coral reef aquarium hobbyists, serves as a valuable model organism in the study of cnidarian-algal symbiosis. Typically a polyp harbors one species of algae. Via photosynthesis, these provide energy for the coral, and aid in calcification. The algae benefit from a safe environment, and consume the carbon dioxide and nitrogenous waste produced by the polyp. Due to the strain the algae can put on the polyp, stress on the coral often drives the coral to eject the algae. Mass ejections are known as coral bleaching, because the algae contribute to coral's brown coloration; other colors, however, are due to host coral pigments, such as GFPs (green fluorescent protein). Ejection increases the polyp's chances of surviving short-term stress—they can regain algae at a later time. If the stressful conditions persist, the polyp eventually dies.

Feeding
Polyps feed on a variety of small organisms, from microscopic plankton to small fish. The polyp's tentacles immobilize or kill prey using their nematocysts. The tentacles then contract to bring the prey into the stomach. Once digested, the stomach reopens, allowing the elimination of waste products and the beginning of the next hunting cycle.
These poisons are usually too weak to harm humans. An exception is fire coral.

Thursday, April 8, 2010

Robotics

Robotics is the engineering science and technology of robots, and their design, manufacture, application, and structural disposition. Robotics is related to electronics, mechanics, and software. The word robot was introduced to the public by Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots), published in 1920. The term "robotics" was coined by Isaac Asimov in his 1941 science fiction short-story "Liar!".

Origins
Stories of artificial helpers and companions and attempts to create them have a long history, but fully autonomous machines only appeared in the 20th century. The first digitally operated and programmable robot, the Unimate, was installed in 1961 to lift hot pieces of metal from a die casting machine and stack them. Today, commercial and industrial robots are in widespread use performing jobs more cheaply or more accurately and reliably than humans. They are also employed in jobs which are too dirty, dangerous, or dull to be suitable for humans. Robots are widely used in manufacturing, assembly, and packing; transport; earth and space exploration; surgery; weaponry; laboratory research; safety; and mass production of consumer and industrial goods.

Robot research
Much of the research in robotics focuses not on specific industrial tasks, but on investigations into new types of robots, alternative ways to think about or design robots, and new ways to manufacture them but other investigations, such as MIT's cyberflora project, are almost wholly academic.
A first particular new innovation in robot design is the opensourcing of robot-projects. To describe the level of advancement of a robot, the term "Generation Robots" can be used. This term is coined by Professor Hans Moravec, Principal Research Scientist at the Carnegie Mellon University Robotics Institute in describing the near future evolution of robot technology. First generation robots, Moravec predicted in 1997, should have an intellectual capacity comparable to perhaps a lizard and should become available by 2010. Because the first generation robot would be incapable of learning, however, Moravec predicts that the second generation robot would be an improvement over the first and become available by 2020, with an intelligence maybe comparable to that of a mouse. The third generation robot should have an intelligence comparable to that of a monkey. Though fourth generation robots, robots with human intelligence, professor Moravec predicts, would become possible, he does not predict this happening before around 2040 or 2050.
The second is Evolutionary Robots. This is a methodology that uses evolutionary computation to help design robots, especially the body form, or motion and behavior controllers, In a similar way to natural evolution, a large population of robots is allowed to compete in some way, or their ability to perform a task is measured using a fitness function. Those that perform worst are removed from the population, and replaced by a new set, which have new behaviors based on those of the winners. Over time the population improves, and eventually a satisfactory robot may appear. This happens without any direct programming of the robots by the researchers. Researchers use this method both to create better robots, and to explore the nature of evolution. Because the process often requires many generations of robots to be simulated, this technique may be run entirely or mostly in simulation, then tested on real robots once the evolved algorithms are good enough. Currently, there are about 1 million industrial robots toiling around the world, and Japan is the top country having high density of utilizing robots in its manufacturing industry.

Education and training
Robotics is a common undergraduate area of study. Some universities offer degrees in robotics.
Robots recently became a popular tool in raising interests in computing for middle and high school students. First year computer science courses at several universities were developed which involves the programming of a robot instead of the traditional software engineering based coursework. Some Master courses in the field of Robotics are also offered.
As the number of robots increases, robotics-related jobs grow. Some jobs require existing job skills, such as building cables, assembling parts, and testing.

Healthcare
Script Pro manufactures a robot designed to help pharmacies fill prescriptions that consist of oral solids or medications in pill form. The pharmacist or pharmacy technician enters the prescription information into its information system. The system, upon determining whether or not the drug is in the robot, will send the information to the robot for filling. The robot has 3 different size vials to fill determined by the size of the pill. The robot technician, user, or pharmacist determines the needed size of the vial based on the tablet when the robot is stocked. Once the vial is filled it is brought up to a conveyor belt that delivers it to a holder that spins the vial and attaches the patient label. Afterwards it is set on another conveyor that delivers the patient’s medication vial to a slot labeled with the patient's name on an LED read out. The pharmacist or technician then checks the contents of the vial to ensure it’s the correct drug for the correct patient and then seals the vials and sends it out front to be picked up. The robot is a very time efficient device that the pharmacy depends on to fill prescriptions.
McKesson’s Robot RX is another healthcare robotics product that helps pharmacies dispense thousands of medications daily with little or no errors. The robot can be ten feet wide and thirty feet long and can hold hundreds of different kinds of medications and thousands of doses. The pharmacy saves many resources like staff members that are otherwise unavailable in a resource scarce industry. It uses an electromechanical head coupled with a pneumatic system to capture each dose and deliver it to its either stocked or dispensed location. The head moves along a single axis while it rotates 180 degrees to pull the medications. During this process it uses barcode technology to verify its pulling the correct drug. It then delivers the drug to a patient specific bin on a conveyor belt. Once the bin is filled with all of the drugs that a particular patient needs and that the robot stocks, the bin is then released and returned out on the conveyor belt to a technician waiting to load it into a cart for delivery to the floor.

Friday, April 2, 2010

Carbon chauvinism

Carbon chauvinism is a relatively new term meant to disparage the assumption that extraterrestrial life will resemble life on Earth.

Concept
Carbon chauvinism is applied to those who assume that the molecules responsible for the chemical processes of life must be constructed primarily from carbon. It suggests that human beings, as carbon-based life forms who have never encountered any life that has evolved outside the earth’s environment, may find it difficult to envision radically different biochemistries. The term was used as early as 1973, when Carl Sagan described it and other human chauvinisms that limit imagination of possible extraterrestrial life in his Cosmic Connection.
In a 1999 Reason magazine article discussing the theory of a fine-tuned universe, Kenneth Silber quotes astrophysicist Victor J. Stenger using the term:

"There is no good reason, says Stenger, to "assume that there's only one kind of life possible" - we know far too little about life in our own universe, let alone "other" universes, to reach such a conclusion. Stenger denounces as "carbon chauvinism" the assumption that life requires carbon; other chemical elements, such as silicon, can also form molecules of considerable complexity. Indeed, Stenger ventures, it is "molecular chauvinism" to assume that molecules are required at all; in a universe with different properties, atomic nuclei or other structures might assemble in totally unfamiliar ways".

Criticism
Carbon has unique features that make it suitable for life possessed by no other element. Only two elements, carbon and silicon, can create molecules that are sufficiently large enough to carry biological information. However, carbon, unlike silicon has the important property that it can form chemical bonds with diverse types of other atoms and so create the chemical versatility needed to enable the chemical reactions needed for biology such as metabolism. Elements creating organic functional groups with carbon include hydrogen, oxygen, nitrogen, phosphorus, sulfur, and diverse metals, such as iron, magnesium, and zinc. The only alternative, silicon, interacts with very few other types of atoms. Moreover, where it does it creates molecules that "are monotonous compared with the combinatorial universe of organic macromolecules."

Carbon-based life
Carbon forms the backbone of biology for all life on Earth. Complex molecules are made up of carbon bonded with other elements, especially oxygen, hydrogen and nitrogen, and carbon is able to bond with all of these because of its four valence electrons. It is often assumed in astrobiology that if life exists somewhere else in the universe, it will also be carbon based. This assumption is referred to by critics as carbon chauvinism.
In cinematic and literary science fiction, a moment when man-made machines cross from nonliving to living, is often posited, this new form would be the first example of non-carbon-based life. Since the advent of the microprocessor in the late 1960s, these machines are often classed as computers (or computer-guided robots) and filed under "silicon-based life", even though the silicon backing matrix of these processors is not nearly as fundamental to their operation as carbon is for "wet life".

Characteristics of carbon as a basis for life
The two most important characteristics of carbon as a basis for the chemistry of life, are that it has four valence bonds and that the energy required to make or break a bond is just at an appropriate level for building molecules which are not only stable, but also reactive. The fact that carbon atoms bond readily to other carbon atoms allows for the building of arbitrarily long and complex molecules.
There are not many other elements which appear to be even promising candidates for supporting life-like behavior, but the most frequent alternative suggested is silicon. This is in the same group in the Periodic Table of elements and therefore also has four valence bonds. It also bonds to itself, but generally in the form of crystal lattices, less amenable to a complete source of life, rather than long chains. However, its compounds are generally highly stable and do not support the ability to readily re-combine in different permutations in a manner that would plausibly support life-like processes.
This speculation of a life based on the chemistry of silicon is clearly distinct from "silicon-based life" in the above sense of artificial intelligence based on electronic processes utilizing silicon integrated circuits.

Key carbon-based molecules in the life processes
The most notable groups of chemicals used in the processes of living organisms include:
a) Proteins, which are the building blocks from which the structures of living organisms are constructed (this includes almost all enzymes, which catalyse organic chemical reactions
b) Nucleic acids, which carry genetic information
c) Carbohydrates, which store energy in a form that can be used by living cells
d) Fats, which also store energy, but in a more concentrated form, and which may be stored for extended periods in the bodies of animals.
 
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