Joke

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Internet magic

Two teenagers decided to introduce their elderly mother to the magic of the internet. The first move was to access the popular Ask Jeeves website. They told her it could answer any question she had.

The mother was very skeptical until one of the teens said, “It,s true, Mom. Think of something to ask.” After about a minute thought, the mother then responded, “How is Aunt Helen feeling?”

Car Privileges

The mother and father had just given their teenage daughter family-car privileges. On Saturday night she returned home very late from a party.

The next morning her father went out to the driveway to get the newspaper and came back into the house frowning. At 11:30 AM the girl sleepily walked into the kitchen, and her father asked her, “Sweetheart, what time did you get in last night?”

“Not too late, Dad,” she replied nervously.

Calmly, her father said, “Then, honey, I’ll have to talk with the paperboy about putting my paper under the front tire of the car.”

— All men are idiots, and I married their king.
— Your kid may be an honors student, but you’re still an idiot.
— I brake for no apparent reason.
— Time is what keeps everything from happening all at once.
— Out of my mind. Back in five minutes.
— I didn’t fight my way to the top of the food chain to be a vegetarian.
— Women who seek to be equal to men lack ambition.
— Reality is a crutch for people who can’t handle drugs.
— I don’t suffer from insanity, I enjoy every minute of it.
— Hard work pays off in the future. Laziness pays off NOW.
— Give me ambiguity or give me something else.
— Always remember you’re unique, just like everyone else.
— Puritanism: the haunting fear that someone somewhere may be happy.
— Consciousness cuts into my napping.
— Beauty is in the eye of the beer holder.
— There are 3 kinds of people: those who can count and those who can’t.
— Keep honking. I’m reloading.

I’m getting a new car. You know what kind of car I’m getting? I’m getting a Honda Civic because those are very safe cars. And I know ’cause I saw a guy total one the other day when I ran him off the road.

Harry and Martha drank their coffee as they listened to the morning weather report.

“There will be three to five inches of snow today. You must park your cars on the odd-numbered side of the street.”

Harry got up from his coffee to move the car.

Two days later, they sat down with their cup of coffee and listened the weather forecast.

“There will be two to four inches of snow today. You must park your cars on the even-numbered side of the street.”

Harry got up from his coffee to move the car.

Three days later, they tuned in to the weather report.

“There will be six to eight inches of snow today. You must park your cars on the….” The power went off.

He said to Martha, “What am I going to do now?”

Martha said, “Just leave the car in the garage.”

source: http://www.jokes.com

Atlantis

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Plato’s account

Plato’s dialogues Timaeus and Critias, written in 360 BC, contain the earliest references to Atlantis. For unknown reasons, Plato never completed Critias; however, the scholar Benjamin Jowett, among others, argues that Plato originally planned a third dialogue titled Hermocrates. John V. Luce assumes that Plato, after describing the origin of the world and mankind in Timaeus and the allegorical perfect society of ancient Athens and its successful defense against an antagonistic Atlantis in Critias, would have made the strategy of the Greek civilization during their conflict with the Persians a subject of discussion in the Hermocrates. Plato introduced Atlantis in Timaeus:

For it is related in our records how once upon a time your State stayed the course of a mighty host, which, starting from a distant point in the Atlantic ocean, was insolently advancing to attack the whole of Europe, and Asia to boot. For the ocean there was at that time navigable; for in front of the mouth which you Greeks call, as you say, ‘the pillars of Heracles,’ there lay an island which was larger than Libya and Asia together; and it was possible for the travelers of that time to cross from it to the other islands, and from the islands to the whole of the continent over against them which encompasses that veritable ocean. For all that we have here, lying within the mouth of which we speak, is evidently a haven having a narrow entrance; but that yonder is a real ocean, and the land surrounding it may most rightly be called, in the fullest and truest sense, a continent. Now in this island of Atlantis there existed a confederation of kings, of great and marvelous power, which held sway over all the island, and over many other islands also and parts of the continent.

The four persons appearing in those two dialogues are the politicians Critias and Hermocrates as well as the philosophers Socrates and Timaeus of Locri, although only Critias speaks of Atlantis. While most likely all of these people actually lived, these dialogues, written as if recorded, may have been the invention of Plato. In his works Plato makes extensive use of the Socratic dialogues in order to discuss contrary positions within the context of a supposition.

The Timaeus begins with an introduction, followed by an account of the creations and structure of the universe and ancient civilizations. In the introduction, Socrates muses about the perfect society, described in Plato’s Republic (ca. 380 BC), and wonders if he and his guests might recollect a story which exemplifies such a society. Critias mentions an allegedly historical tale that would make the perfect example, and follows by describing Atlantis as is recorded in the Critias. In his account, ancient Athens seems to represent the “perfect society” and Atlantis its opponent, representing the very antithesis of the “perfect” traits described in the Republic. Critias claims that his accounts of ancient Athens and Atlantis stem from a visit to Egypt by the legendary Athenian lawgiver Solon in the 6th century BC. In Egypt, Solon met a priest of Sais, who translated the history of ancient Athens and Atlantis, recorded on papyri in Egyptian hieroglyphs, into Greek. According to Plutarch, Solon met with “Psenophis of Heliopolis, and Sonchis the Saite, the most learned of all the priests”;^[5] Plutarch refers here to events that would have happened five centuries before he wrote of them.

According to Critias, the Hellenic gods of old divided the land so that each god might own a lot; Poseidon was appropriately, and to his liking, bequeathed the island of Atlantis. The island was larger than Ancient Libya and Asia Minor combined, but it afterwards was sunk by an earthquake and became an impassable mud shoal, inhibiting travel to any part of the ocean. The Egyptians, Plato asserted, described Atlantis as an island comprising mostly mountains in the northern portions and along the shore, and encompassing a great plain of an oblong shape in the south “extending in one direction three thousand stadia [about 555 km; 345 mi], but across the center inland it was two thousand stadia [about 370 km; 230 mi].” Fifty stadia [9 km; 6 mi] from the coast was a mountain that was low on all sides…broke it off all round about … the central island itself was five stades in diameter [about 0.92 km; 0.57 mi].

In Plato’s myth, Poseidon fell in love with Cleito, the daughter of Evenor and Leucippe, who bore him five pairs of male twins. The eldest of these, Atlas, was made rightful king of the entire island and the ocean (called the Atlantic Ocean in his honor), and was given the mountain of his birth and the surrounding area as his fiefdom. Atlas’s twin Gadeirus, or Eumelus in Greek, was given the extremity of the island towards the Pillars of Heracles. The other four pairs of twins — Ampheres and Evaemon, Mneseus and Autochthon, Elasippus and Mestor, and Azaes and Diaprepes — were also given “rule over many men, and a large territory.”

Poseidon carved the mountain where his love dwelt into a palace and enclosed it with three circular moats of increasing width, varying from one to three stadia and separated by rings of land proportional in size. The Atlanteans then built bridges northward from the mountain, making a route to the rest of the island. They dug a great canal to the sea, and alongside the bridges carved tunnels into the rings of rock so that ships could pass into the city around the mountain; they carved docks from the rock walls of the moats. Every passage to the city was guarded by gates and towers, and a wall surrounded each of the city’s rings. The walls were constructed of red, white and black rock quarried from the moats, and were covered with brass, tin and the precious metal orichalcum, respectively.

According to Critias, 9,000 years before his lifetime a war took place between those outside the Pillars of Hercules at the Strait of Gibraltar and those who dwelt within them. The Atlanteans had conquered the parts of Libya within the Pillars of Heracles as far as Egypt and the European continent as far as Tyrrhenia, and subjected its people to slavery. The Athenians led an alliance of resistors against the Atlantean empire, and as the alliance disintegrated, prevailed alone against the empire, liberating the occupied lands.

But at a later time there occurred portentous earthquakes and floods, and one grievous day and night befell them, when the whole body of your warriors was swallowed up by the earth, and the island of Atlantis in like manner was swallowed up by the sea and vanished; wherefore also the ocean at that spot has now become impassable and unsearchable, being blocked up by the shoal mud which the island created as it settled down.

Source: wikipedia

Superconductivity

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Elementary properties of superconductors

Most of the physical properties of superconductors vary from material to material, such as the heat capacity and the critical temperature, critical field, and critical current density at which superconductivity is destroyed.

On the other hand, there is a class of properties that are independent of the underlying material. For instance, all superconductors have exactly zero resistivity to low applied currents when there is no magnetic field present. The existence of these “universal” properties implies that superconductivity is a thermodynamic phase, and thus possess certain distinguishing properties which are largely independent of microscopic details.

Zero electrical “dc” resistance

Electric cables for accelerators at CERN: top, regular cables for LEP; bottom, superconducting cables for the LHC.

The simplest method to measure the electrical resistance of a sample of some material is to place it in an electrical circuit in series with a current source I and measure the resulting voltage V across the sample. The resistance of the sample is given by Ohm’s law as . . If the voltage is zero, this means that the resistance is zero and that the sample is in the superconducting state.

Superconductors are also able to maintain a current with no applied voltage whatsoever, a property exploited in superconducting electromagnets such as those found in MRI machines. Experiments have demonstrated that currents in superconducting coils can persist for years without any measurable degradation. Experimental evidence points to a current lifetime of at least 100,000 years. Theoretical estimates for the lifetime of a persistent current can exceed the estimated lifetime of the universe, depending on the wire geometry and the temperature. Thus, a superconductor does not have exactly zero resistance, however, the resistance is negligibly small.

In a normal conductor, an electrical current may be visualized as a fluid of electrons moving across a heavy ionic lattice. The electrons are constantly colliding with the ions in the lattice, and during each collision some of the energy carried by the current is absorbed by the lattice and converted into heat, which is essentially the vibrational kinetic energy of the lattice ions. As a result, the energy carried by the current is constantly being dissipated. This is the phenomenon of electrical resistance.

The situation is different in a superconductor. In a conventional superconductor, the electronic fluid cannot be resolved into individual electrons. Instead, it consists of bound pairs of electrons known as Cooper pairs. This pairing is caused by an attractive force between electrons from the exchange of phonons. Due to quantum mechanics, the energy spectrum of this Cooper pair fluid possesses an energy gap, meaning there is a minimum amount of energy ΔE that must be supplied in order to excite the fluid. Therefore, if ΔE is larger than the thermal energy of the lattice, given by kT, where k is Boltzmann’s constant and T is the temperature, the fluid will not be scattered by the lattice. The Cooper pair fluid is thus a superfluid, meaning it can flow without energy dissipation.

In a class of superconductors known as Type II superconductors, including all known high-temperature superconductors, an extremely small amount of resistivity appears at temperatures not too far below the nominal superconducting transition when an electrical current is applied in conjunction with a strong magnetic field, which may be caused by the electrical current. This is due to the motion of vortices in the electronic superfluid, which dissipates some of the energy carried by the current. If the current is sufficiently small, the vortices are stationary, and the resistivity vanishes. The resistance due to this effect is tiny compared with that of non-superconducting materials, but must be taken into account in sensitive experiments. However, as the temperature decreases far enough below the nominal superconducting transition, these vortices can become frozen into a disordered but stationary phase known as a “vortex glass”. Below this vortex glass transition temperature, the resistance of the material becomes truly zero.

Superconducting phase transition

In superconducting materials, the characteristics of superconductivity appear when the temperature T is lowered below a critical temperature T_c. The value of this critical temperature varies from material to material. Conventional superconductors usually have critical temperatures ranging from around 20 K (kelvins) to less than 1 K. Solid mercury, for example, has a critical temperature of 4.2 K. As of 2001, the highest critical temperature found for a conventional superconductor is 39 K for magnesium diboride (MgB₂)^[2], although this material displays enough exotic properties that there is doubt about classifying it as a “conventional” superconductor. Cuprate superconductors can have much higher critical temperatures: YBa₂Cu₃O₇, one of the first cuprate superconductors to be discovered, has a critical temperature of 92 K, and mercury-based cuprates have been found with critical temperatures in excess of 130 K. The explanation for these high critical temperatures remains unknown. Electron pairing due to phonon exchanges explains superconductivity in conventional superconductors, but it does not explain superconductivity in the newer superconductors that have a very high critical temperature.

Similarly, at a fixed temperature below the critical temperature, superconducting materials cease to superconduct when an external magnetic field is applied which is greater than the critical magnetic field. This is because the Gibbs free energy of the superconducting phase increases quadratically with the magnetic field while the free energy of the normal phase is roughly independent of the magnetic field. If the material superconducts in the absence of a field, then the superconducting phase free energy is lower than that of the normal phase and so for some finite value of the magnetic field (proportional to the square root of the difference of the free energies at zero magnetic field) the two free energies will be equal and a phase transition to the normal phase will occur. More generally, a higher temperature and a stronger magnetic field lead to a smaller fraction of the electrons in the superconducting band and consequently a longer London penetration depth of external magnetic fields and currents. The penetration depth becomes infinite at the phase transition.

The onset of superconductivity is accompanied by abrupt changes in various physical properties, which is the hallmark of a phase transition. For example, the electronic heat capacity is proportional to the temperature in the normal (non-superconducting) regime. At the superconducting transition, it suffers a discontinuous jump and thereafter ceases to be linear. At low temperatures, it varies instead as e^{−α /T} for some constant α. This exponential behavior is one of the pieces of evidence for the existence of the energy gap.

The order of the superconducting phase transition was long a matter of debate. Experiments indicate that the transition is second-order, meaning there is no latent heat. However in the presence of an external magnetic field there is latent heat, as a result of the fact that the superconducting phase has a lower entropy below the critical temperature than the normal phase. It has experimentally demonstrated  that, as a consequence, when the magnetic field is increased beyond the critical field, the resulting phase transition leads to a decrease in the temperature of the superconducting material.

Calculations in the 1970s suggested that it may actually be weakly first-order due to the effect of long-range fluctuations in the electromagnetic field. In the 1980s it was shown theoretically with the help of a disorder field theory, in which the vortex lines of the superconductor play a major role, that the transition is of second order within the type II regime and of first order (i.e., latent heat) within the type I regime, and that the two regions are separated by a tricritical point The results were confirmed by Monte Carlo computer simulations in Ref.

Source: wikipedia

Albert Einstein

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Albert Einstein (German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n ; English: /ˈælbərt ˈaɪnstaɪn/; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist. He is best known for his theory of relativity and specifically mass–energy equivalence, expressed by the equation E = mc². Einstein received the 1921 Nobel Prize in Physics “for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect.”

Einstein’s many contributions to physics include:

• Special theory of relativity, which reconciled mechanics with electromagnetism
• General theory of relativity, a new theory of gravitation which added the principle of equivalence to the principle of relativity
• Founding of relativistic cosmology with a cosmological constant
• The first post-Newtonian expansions for the perihelion advance of planet Mercury and frame-dragging
• The deflection of light by gravity and gravitational lensing
• An explanation for capillary action
• The first fluctuation dissipation theorem which explained the Brownian movement of molecules
• The photon theory and wave-particle duality from the thermodynamic properties of light
• The quantum theory of atomic motion in solids
• Zero-point energy
• The semiclassical version of the Schrodinger equation
• Relations for atomic transition probabilities which predicted stimulated emission
• The quantum theory of a monatomic gas which predicted Bose-Einstein condensation
• The EPR paradox
• A program for a unified field theory by the geometrization of physics.

Einstein published more than 300 scientific works and more than 150 non-scientific works. In 1999 Time magazine named him the “Person of the Century“, and in the words of Einstein biographer Don Howard, “to the scientifically literate and the public at large, Einstein is synonymous with genius.”

Patent office

The ‘Einsteinhaus’ on the Kramgasse in Berne where Einstein lived with Mileva on the first floor during his Annus Mirabilis

Following graduation, Einstein could not find a teaching post. After almost two years of searching, a former classmate’s father helped him get a job in Berne, at the Federal Office for Intellectual Property,^[14] the patent office, as an assistant examiner. His responsibility was evaluating patent applications for electromagnetic devices. In 1903, Einstein’s position at the Swiss Patent Office was made permanent, although he was passed over for promotion until he “fully mastered machine technology”.

With friends he met in Berne, Einstein formed a weekly discussion club on science and philosophy, jokingly named “The Olympia Academy“. Their readings included Poincaré, Mach, and Hume, who influenced Einstein’s scientific and philosophical outlook.

During this period Einstein had almost no personal contact with the physics community. Much of his work at the patent office related to questions about transmission of electric signals and electrical-mechanical synchronization of time: two technical problems that show up conspicuously in the thought experiments that eventually led Einstein to his radical conclusions about the nature of light and the fundamental connection between space and time.

Marriage and family life

Einstein and Mileva Marić had a daughter they called Lieserl, who was born in early 1902, probably in Novi Sad. Her fate is uncertain after 1903.

Einstein married Mileva on 6 January 1903, although his mother had objected to the match because she had a prejudice against Serbs and thought Marić “too old” and “physically defective.”^{[19] [20]} Their relationship was for a time a personal and intellectual partnership. In a letter to her, Einstein called Marić “a creature who is my equal and who is as strong and independent as I am.” There has been occasional debate about whether Marić influenced Einstein’s work, however, the overwhelming consensus amongst academic historians of science is that she did not. On 14 May 1904, Albert and Mileva’s first son, Hans Albert Einstein, was born in Berne, Switzerland. Their second son, Eduard, was born in Zurich on 28 July 1910.

Albert and Marić divorced on 14 February 1919, having lived apart for five years. On 2 June of that year, Einstein married Elsa Löwenthal (née Einstein), who had nursed him through an illness. Elsa was Albert’s first cousin maternally and his second cousin paternally. Together the Einsteins raised Margot and Ilse, Elsa’s daughters from her first marriage. Their union produced no children.

Annus Mirabilis and special relativity

Albert Einstein, 1905

In 1905, while he was working in the patent office, Einstein had four papers published in the Annalen der Physik, the leading German physics journal. These are the papers that history has come to call the Annus Mirabilis Papers:

• His paper on the particulate nature of light put forward the idea that certain experimental results, notably the photoelectric effect, could be simply understood from the postulate that light interacts with matter as discrete “packets” (quanta) of energy, an idea that had been introduced by Max Planck in 1900 as a purely mathematical manipulation, and which seemed to contradict contemporary wave theories of light (Einstein 1905a).
• His paper on Brownian motion explained the random movement of very small objects as direct evidence of molecular action, thus supporting the atomic theory. (Einstein 1905c)
• His paper on the electrodynamics of moving bodies introduced the radical theory of special relativity, which showed that the observed independence of the speed of light on the observer’s state of motion required fundamental changes to the notion of simultaneity. Consequences of this include the time-space frame of a moving body slowing down and contracting (in the direction of motion) relative to the frame of the observer. This paper also argued that the idea of a luminiferous aether—one of the leading theoretical entities in physics at the time—was superfluous. (Einstein 1905d)
• In his paper on mass–energy equivalence (previously considered to be distinct concepts), Einstein deduced from his equations of special relativity what has been called the twentieth century’s most well known equation: E = mc². This suggests that tiny amounts of mass could be converted into huge amounts of energy and presaged the development of nuclear power. (Einstein 1905e)

All four papers are today recognized as tremendous achievements—and hence 1905 is known as Einstein’s “Wonderful Year“. At the time, however, they were not noticed by most physicists as being important, and many of those who did notice them rejected them outright. Some of this work—such as the theory of light quanta—remained controversial for years.

At the age of 26, having studied under Alfred Kleiner, Professor of Experimental Physics, Einstein was awarded a PhD by the University of Zurich. His dissertation was entitled A New Determination of Molecular Dimensions. (Einstein 1905b)

source: wikipedia

Biotechnology

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Insulin crystals.

Biotechnology is technology based on biology, especially when used in agriculture, food science, and medicine. United Nations Convention on Biological Diversity defines biotechnology as:

Any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use.

Biotechnology is often used to refer to genetic engineering technology of the 21st century, however the term encompasses a wider range and history of procedures for modifying biological organisms according to the needs of humanity, going back to the initial modifications of native plants into improved food crops through artificial selection and hybridization. Bioengineering is the science upon which all biotechnological applications are based. With the development of new approaches and modern techniques, traditional biotechnology industries are also acquiring new horizons enabling them to improve the quality of their products and increase the productivity of their systems.

Before 1971, the term, biotechnology, was primarily used in the food processing and agriculture industries. Since the 1970s, it began to be used by the Western scientific establishment to refer to laboratory-based techniques being developed in biological research, such as recombinant DNA or tissue culture-based processes, or horizontal gene transfer in living plants, using vectors such as the Agrobacterium bacteria to transfer DNA into a host organism. In fact, the term should be used in a much broader sense to describe the whole range of methods, both ancient and modern, used to manipulate organic materials to reach the demands of food production. So the term could be defined as, “The application of indigenous and/or scientific knowledge to the management of (parts of) microorganisms, or of cells and tissues of higher organisms, so that these supply goods and services of use to the food industry and its consumers.^[2]

Biotechnology combines disciplines like genetics, molecular biology, biochemistry, embryology and cell biology, which are in turn linked to practical disciplines like chemical engineering, information technology, and biorobotics. Patho-biotechnology describes the exploitation of pathogens or pathogen derived compounds for beneficial effect.

Although not normally thought of as biotechnology, agriculture clearly fits the broad definition of “using a biological system to make products” such that the cultivation of plants may be viewed as the earliest biotechnological enterprise. Agriculture has been theorized to have become the dominant way of producing food since the Neolithic Revolution. The processes and methods of agriculture have been refined by other mechanical and biological sciences since its inception. Through early biotechnology, farmers were able to select the best suited and highest-yield crops to produce enough food to support a growing population. Other uses of biotechnology were required as crops and fields became increasingly large and difficult to maintain. Specific organisms and organism by-products were used to fertilize, restore nitrogen, and control pests. Throughout the use of agriculture, farmers have inadvertently altered the genetics of their crops through introducing them to new environments and breeding them with other plants–one of the first forms of biotechnology. Cultures such as those in Mesopotamia, Egypt, and India developed the process of brewing beer. It is still done by the same basic method of using malted grains (containing enzymes) to convert starch from grains into sugar and then adding specific yeasts to produce beer. In this process the carbohydrates in the grains were broken down into alcohols such as ethanol. Ancient Indians also used the juices of the plant Ephedra vulgaris and used to call it Soma. Later other cultures produced the process of Lactic acid fermentation which allowed the fermentation and preservation of other forms of food. Fermentation was also used in this time period to produce leavened bread. Although the process of fermentation was not fully understood until Louis Pasteur’s work in 1857, it is still the first use of biotechnology to convert a food source into another form.

Combinations of plants and other organisms were used as medications in many early civilizations. Since as early as 200 BC, people began to use disabled or minute amounts of infectious agents to immunize themselves against infections. These and similar processes have been refined in modern medicine and have led to many developments such as antibiotics, vaccines, and other methods of fighting sickness.

In the early twentieth century scientists gained a greater understanding of microbiology and explored ways of manufacturing specific products. In 1917, Chaim Weizmann first used a pure microbiological culture in an industrial process, that of manufacturing corn starch using Clostridium acetobutylicum, to produce acetone, which the United Kingdom desperately needed to manufacture explosives during World War I.

The field of modern biotechnology is thought to have largely begun on June 16, 1980, when the United States Supreme Court ruled that a genetically-modified microorganism could be patented in the case of Diamond v. Chakrabarty. Indian-born Ananda Chakrabarty, working for General Electric, had developed a bacterium (derived from the Pseudomonas genus) capable of breaking down crude oil, which he proposed to use in treating oil spills.

Revenue in the industry is expected to grow by 12.9% in 2008. Another factor influencing the biotechnology sector’s success is improved intellectual property rights legislation — and enforcement — worldwide, as well as strengthened demand for medical and pharmaceutical products to cope with an ageing, and ailing, U.S. population.

Rising demand for biofuels is expected to be good news for the biotechnology sector, with the Department of Energy estimating ethanol usage could reduce U.S. petroleum-derived fuel consumption by up to 30% by 2030. The biotechnology sector has allowed the U.S. farming industry to rapidly increase its supply of corn and soybeans — the main inputs into biofuels — by developing genetically-modified seeds which are resistant to pests and drought. By boosting farm productivity, biotechnology plays a crucial role in ensuring that biofuel production targets are met.

Source: Wikipedia

Atom

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Helium atom

The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of Hydrogen-1, which is the only stable nuclide with no neutron). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive or negative charge and is an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determine the isotope of the element.

The name atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the ‘atom’ was not indivisible. The principles of quantum mechanics were used to successfully model the atom.^[1][2]

Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.9% of an atom’s mass is concentrated in the nucleus,^{[note 1]} with protons and neutrons having roughly equal mass. Each element has at least one isotope with unstable nuclei that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus.^[3] Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom’s magnetic properties.

Subatomic particles

Though the word atom originally denoted a particle that cannot be cut into smaller particles, in modern scientific usage the atom is composed of various subatomic particles. The constituent particles of an atom are the electron, the proton and the neutron. However, the hydrogen-1 atom has no neutrons and a positive hydrogen ion has no electrons.

The electron is by far the least massive of these particles at 9.11 × 10⁻³¹ kg, with a negative electrical charge and a size that is too small to be measured using available techniques.^[34] Protons have a positive charge and a mass 1,836 times that of the electron, at 1.6726 × 10⁻²⁷ kg, although this can be reduced by changes to the energy binding the proton into an atom. Neutrons have no electrical charge and have a free mass of 1,839 times the mass of electrons, or 1.6929 × 10⁻²⁷ kg. Neutrons and protons have comparable dimensions—on the order of 2.5 × 10⁻¹⁵ m—although the ‘surface’ of these particles is not sharply defined.

In the Standard Model of physics, both protons and neutrons are composed of elementary particles called quarks. The quark belongs to the fermion group of particles, and is one of the two basic constituents of matter—the other being the lepton, of which the electron is an example. There are six types of quarks, each having a fractional electric charge of either +2/3 or −1/3. Protons are composed of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks. This distinction accounts for the difference in mass and charge between the two particles. The quarks are held together by the strong nuclear force, which is mediated by gluons. The gluon is a member of the family of gauge bosons, which are elementary particles that mediate physical forces.

Nucleus

The binding energy needed for a nucleon to escape the nucleus, for various isotopes.

All the bound protons and neutrons in an atom make up a tiny atomic nucleus, and are collectively called nucleons. The radius of a nucleus is approximately equal to fm, where A is the total number of nucleons.^[39] This is much smaller than the radius of the atom, which is on the order of 10⁵ fm. The nucleons are bound together by a short-ranged attractive potential called the residual strong force. At distances smaller than 2.5 fm this force is much more powerful than the electrostatic force that causes positively charged protons to repel each other.^[40]

Atoms of the same element have the same number of protons, called the atomic number. Within a single element, the number of neutrons may vary, determining the isotope of that element. The total number of protons and neutrons determine the nuclide. The number of neutrons relative to the protons determines the stability of the nucleus, with certain isotopes undergoing radioactive decay.^[41]

The neutron and the proton are different types of fermions. The Pauli exclusion principle is a quantum mechanical effect that prohibits identical fermions (such as multiple protons) from occupying the same quantum physical state at the same time. Thus every proton in the nucleus must occupy a different state, with its own energy level, and the same rule applies to all of the neutrons. (This prohibition does not apply to a proton and neutron occupying the same quantum state.)^[42]

For atoms with low atomic numbers, a nucleus that has a different number of protons than neutrons can potentially drop to a lower energy state through a radioactive decay that causes the number of protons and neutrons to more closely match. As a result, atoms with roughly matching numbers of protons and neutrons are more stable against decay. However, with increasing atomic number, the mutual repulsion of the protons requires an increasing proportion of neutrons to maintain the stability of the nucleus, which modifies this trend. Thus, there are no stable nuclei with equal proton and neutron numbers above atomic number Z = 20 (calcium); and as Z increases toward the heaviest nuclei, the ratio of neutrons per proton required for stability increases to about 1.5.

Illustration of a nuclear fusion process that forms a deuterium nucleus, consisting of a proton and a neutron, from two protons. A positron (e⁺)—an antimatter electron—is emitted along with an electron neutrino.

The number of protons and neutrons in the atomic nucleus can be modified, although this can require very high energies because of the strong force. Nuclear fusion occurs when multiple atomic particles join to form a heavier nucleus, such as through the energetic collision of two nuclei. For example, at the core of the Sun protons require energies of 3–10 keV to overcome their mutual repulsion—the coulomb barrier—and fuse together into a single nucleus. Nuclear fission is the opposite process, causing a nucleus to split into two smaller nuclei—usually through radioactive decay. The nucleus can also be modified through bombardment by high energy subatomic particles or photons. If this modifies the number of protons in a nucleus, the atom changes to a different chemical element.

If the mass of the nucleus following a fusion reaction is less than the sum of the masses of the separate particles, then the difference between these two values is emitted as energy, as described by Albert Einstein‘s mass–energy equivalence formula, E = mc², where m is the mass loss and c is the speed of light. This deficit is the binding energy of the nucleus.

The fusion of two nuclei that have lower atomic numbers than iron and nickel is usually an exothermic process that releases more energy than is required to bring them together. It is this energy-releasing process that makes nuclear fusion in stars a self-sustaining reaction. For heavier nuclei, the total binding energy begins to decrease. That means fusion processes with nuclei that have higher atomic numbers is an endothermic process. These more massive nuclei can not undergo an energy-producing fusion reaction that can sustain the hydrostatic equilibrium of a star.

Electron cloud

A potential well, showing the minimum energy V(x) needed to reach each position x. A particle with energy E is constrained to a range of positions between x₁ and x₂.

The electrons in an atom are attracted to the protons in the nucleus by the electromagnetic force. This force binds the electrons inside an electrostatic potential well surrounding the smaller nucleus, which means that an external source of energy is needed in order for the electron to escape. The closer an electron is to the nucleus, the greater the attractive force. Hence electrons bound near the center of the potential well require more energy to escape than those at greater separations.

Electrons, like other particles, have properties of both a particle and a wave. The electron cloud is a region inside the potential well where each electron forms a type of three-dimensional standing wave—a wave form that does not move relative to the nucleus. This behavior is defined by an atomic orbital, a mathematical function that characterises the probability that an electron will appear to be at a particular location when its position is measured. Only a discrete (or quantized) set of these orbitals exist around the nucleus, as other possible wave patterns will rapidly decay into a more stable form. Orbitals can have one or more ring or node structures, and they differ from each other in size, shape and orientation.

Wave functions of the first five atomic orbitals. The three 2p orbitals each display a single angular node that has an orientation and a minimum at the center.

Each atomic orbital corresponds to a particular energy level of the electron. The electron can change its state to a higher energy level by absorbing a photon with sufficient energy to boost it into the new quantum state. Likewise, through spontaneous emission, an electron in a higher energy state can drop to a lower energy state while radiating the excess energy as a photon. These characteristic energy values, defined by the differences in the energies of the quantum states, are responsible for atomic spectral lines.

The amount of energy needed to remove or add an electron (the electron binding energy) is far less than the binding energy of nucleons. For example, it requires only 13.6 eV to strip a ground-state electron from a hydrogen atom, compared to 2.23 Mev for splitting a deuterium nucleus. Atoms are electrically neutral if they have an equal number of protons and electrons. Atoms that have either a deficit or a surplus of electrons are called ions. Electrons that are farthest from the nucleus may be transferred to other nearby atoms or shared between atoms. By this mechanism, atoms are able to bond into molecules and other types of chemical compounds like ionic and covalent network crystals.

Sources: Wikipedia

The Best VoIP Technology and The Great E911

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When it comes to Voice over IP, everybody likes a common thing: buzzwords! It starts from “T.38”, and ends in “E911”. The sad truth is however, most people don’t know what these buzzwords actually mean. It also does not help that most providers don’t bother to educate their customers about the subject.

The customer, is led on by various providers, quite literally like sheep to slaughter… They are being told “yes- we have E911! we are the perfect choice for you! you can count on us!” when the fact is that more often than not even the provider is not entirely aware of the limitations of Voice over IP 911. In this article, I shall attempt to list some major concerns and risks when choosing to rely on VoIP E911.

There are simply too many possible points of failure:

1. Let’s start close to home – or better yet – in your home! Anything from a faulty network cable, router, adapter, or other such piece of equipment may bring your voice line down. If you’ve ever tried VoIP I’m sure you know what I’m talking about – it’s not, and will never be as reliable as POTS (Plain Old Telephone System).

2. Carrying on in your home… one thing we cannot live without these days is electricity. With POTS or cellphone, you are not dependent on electricty to power your phone. With VoIP however, no electricity means no phone! Want to dial 911 during a power outage – or worse – someone deliberately cutting off the power to your house… tough luck, no dialtone!

3. And while we on to electricity, don’t think this problem is isolated to your home alone. A power outage can happen anywhere: your house, the node serving your DSL or cable internet, the provider’s data center, or the E911 provider’s data center. Sure- these days most providers have redundant servers and some even have geographic redundancy, and data centers have generators and other such neat equipment designed to keep you rolling. This is all great in theory- until you find out that the generator didn’t kick in, and it took 15 minutes to switch over to a backup data center. 15 minutes is not a lot – but it may become a lot when your life is on the line!

4. Let’s hang on a bit to your internet provider.. we’re not done with them yet! if you’re like me, you experience an internet outage every few weeks. It can last anywhere between 5 minutes, to a whole day! No internet means no VoIP service, and no VoIP service means no E911!

5. And how about the provider’s internet? their data center? their DNS servers? their SIP servers? some providers can be very reliable… but things do happen and outages are not unheard of even with the biggest of providers.

6. Now that we’re done harping on about ISPs, why don’t we take a look at the weakest link – the E911 provider! while I am sure they do their best to ensure reliability, let’s face it – there is no competition in the field. There are a total of 4 real E911 providers in the entire country – all the rest are resellers (read: clueless!). This industry is so new that glitches are bound to happen – and continue to happen for years to come. As a VoIP provider – I can ensure proper routing, high availability, and various other methods to get as close as we can to 100% uptime – it won’t matter one bit if the E911 provider’s server is down.

7. E911 providers are not VoIP providers. This is a bad thing. Why? A VoIP provider delivers thousands, tens of thousands, or even more than that per day. If something is broken – it is soon found – and fixed. An E911 provider deliver very few calls per day, meaning they do not get the sort of production validation a VoIP provider does. Things can be broken for half a day and they’d think “just a slow day”.

8. Things about the sheer number of things that have to be in place to deliver your E911. Call correctly: your gear at home has to work correctly, your ISP has to work correctly, the backbone along the way has to work correctly, the provider’s data center, servers, and internet connect has to work correctly, the VoIP provider’s interconnection with the E911 provider has to work correctly, your telephone number has to be pre-input correctly in the E911 provider’s database, the E911 provider’s servers have to work correctly, the E911 provider has to match your address to the correct PSAP (Public Safety Answering Point), and the E911 has to interconnect properly with the PSAP to deliver the call.

With so many factors and potential breaking points – should a customer really expect to be able to pick up the phone and reach 911 in an emergency? I don’t believe so. And I think it is time providers and regulators alike stop lying to themselves and lying to the nation. VoIP is not POTS, will never be POTS, and will never be as reliable as POTS. Trying to regulate providers into offering E911 will achieve nothing but the delusion of safety among consumers. Such delusion is even more dangerous as consumers end up believing they are safe, because the regulators say so!

The bottom line is: E911 is not reliable. Do yourself a favor, and ignore the buzzwords and hype. If you want to dump POTS – get a cheap cellphone – even a prepaid one – to act as a backup for E911. Do not rely on E911 alone under any circumastances!

I wish you all a very safe, enjoyable experience with Voice over IP!.

About the Author

Nitzan is the President of Future Nine Corporation – a leading provider of Internet Phone Service and Callback and Calling Cards.

SDL Delivers Integrated Automated Translation Technology

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SDL delivers new solution after recent survey shows 40 percent of businesses now more likely to use automated translation

Maidenhead, U.K. – 14th October 2009 – SDL plc, the leading provider of Global Information Management (GIM) solutions, today announced the release of SDL Automated Translation Solutions™ to help companies meet the multilingual communication requirements of global businesses.

Businesses are producing increasing volumes of content that need to be delivered to expanding global markets. Providing this information in the language of the customer is key to new sales, to repeat sales and to customer satisfaction and yet many organizations struggle to provide this, because the cost is too high or it takes too long to translate. With teams dispersed around the globe, internal communications also hit the language barrier.

SDL Automated Translation Solutions™ open up new communications opportunities between people who speak different languages. They enable instant translation of content in corporate websites, documents, instant chat and e-mail. Through tight integration with existing translation processes and the translation supply chain, they provide rapid and highly cost-effective solutions for both ‘gisted’ and high-quality translations.

SDL Automated Translation Solutions provide much greater flexibility to meet the different translation needs of global businesses than has previously been possible:

Instant translation of internal and external communications using plug-ins for Microsoft® Office applications and chat – Instant translation of web pages – Integration of automated translation with translation memory (TM) in the industry-leading SDL Trados® translation productivity suite – Integration of automated translation with TM in the industry-leading translation management application.

SDL Translation Management System™ (SDL TMS™) – Flexibility to use automated translation integrated with human post-editing skills to provide the high-quality translation service, SDL Knowledge-based Translation System® (SDL KbTS™) – Integration of automated translation with many business applications through documented APIs.

“Through our partnership with SDL and our use of their automated translation, we have been able to provide support to our global dealers at 40% lower costs with significantly faster turnaround times,” commented Joe Pstrak, Director, Product Support-Knowledge Management at CNH. “This improves our customer service, by providing our worldwide dealers with solutions to their technical issues every hour of every day of the year, while significantly reducing the workload on support centers. We will continue to look at more ways of using automated translation to improve our business communications.”

“The volume of multilingual content and the velocity with which it’s created is a major force reshaping content practices at global companies,” comments Leonor Ciarlone, lead analyst in Gilbane Group’s content globalization practice. “Gilbane’s own research indicates that machine translation is viewed as one of the top three most valuable technologies going forward.

What’s required is an optimum blend of knowledge worker expertise and automated translation that can tackle volume and velocity challenges with efficiency and transparency. By providing direct integration with enterprise and translator desktops, offerings such as SDL Automated Translation Solutions can deliver real value to operational requirements for multilingual communications.”

SDL is continuing to invest in R&D and has recently added support for automated translation from English into Swedish, with plans to support Finnish and Danish by the end of 2009. In addition, SDL is partnering with a number of academic institutions to further improve the quality of automated translation.

“With the continued explosion of digital content, coupled with the increasing growth in global business, translating large volumes of content for local markets is a considerable challenge and often seen by companies as cost prohibitive,” said Mark Lancaster, CEO and Chairman of SDL.

“If content is needed in your home market, it is also needed in your local markets. Research has shown that the first to the market, and the company who provides the best and most thorough support in those areas, is the one with the competitive edge in that market.

SDL Automated Translation Solutions, integrated as part of a Global Information Management solution, enable companies to get more content into global markets faster and more cost effectively. Companies such as Best Western, CNH, HP, Microsoft and Renault have all benefited from automated translation technology from SDL. With today’s announcement, SDL is enabling its customers to fully integrate automated translation into their existing Global Information Management infrastructure. Global organizations now have the opportunity to substantially improve internal and external communications.”.

About the Author

Telecommuting (working from home) is fast becoming one of the hottest career choices today. People everywhere are escaping the rat race and enjoying the true freedom and flexibility that telecommuting can provide. If you are ready to do the same, visit http://www.Telecommuting123.com/success.html today and download our free guide, “How to Be a Telecommuting Success”

QC Software Leading Provider of Tier 1 WCS Exposes

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QC Software is the leading provider of Tier 1 warehouse control systems to the warehousing and distribution industries. Since 1996, QC Software, utilizing state of the art technology combined with extensive research, development, and rigorous testing, has developed the QC Enterprise suite of products. Designed to be modular in nature, easily configurable, and platform independent, this highly scalable solution satisfies the needs of any size warehouse.

Kevin Tedford is a seasoned industry veteran with over thirty years experience in distribution. His worldwide experience includes Red Prairie (formerly McHugh Software International) where he was one of the original partners, and Forte Industries where he served as Vice President of Technical Operations. In 2005, he founded KT Consulting, LLC.

During his career, he has helped companies achieve distribution related operational efficiency and productivity goals through the appropriate use of material handling automation equipment, information systems and business process improvements. Recently QC Software, the leading WCS (warehouse control system) provider published Tedford’s response to some of the critical issues facing warehouse managers today.

According to Tedford, “Warehouse managers are measured by their ability to get the right product to the right customer, at a service level that meets customers’ requirements or their company’s policy. This translates into having the right amount of inventory in stock, ensuring accurate picking and delivering these services within a certain cost/product ratio. Problems occur when the business environment fluctuates. Your company may be growing or declining or the nature of your company’s orders or products may be changing.

It’s not just the number of orders, but the number of lines per order and quantity per line that has an impact. Perhaps, marketing has decided to offer customized products, so now you have to add value-added services to the distribution center, such as gift wrapping, gift certificates, etc. Providing these additional services requires a whole new business process.”

There are many different factors that could affect a warehouse manager’s performance. Some believe the simple solution just to add more people, however Tedford suggests, “Warehouse managers are looking at the easiest way to solve a specific problem. If your business is growing and volume is increasing, you may think the obvious solution is to add more employees. Or it could be adding a whole new operation in the facility, such as value-added services.

The way in which a warehouse manager reacts to the problems could be correct from a micro perspective, but there comes a time when you need to step back and reevaluate the whole business process in the warehouse to determine if there is a better way to meet your high level objectives at the lowest cost. After all, the goal of a warehouse is to be a low cost operation, while meeting or exceeding customer service targets.”

Tedford also noted there are certain actions that warehouse management can take that will have a significant impact, notable, “If the cost of operations and the cost per unit are starting to increase, it’s probably the result of the law of diminishing returns. If you double your business and double your workforce, productivity may not double.

The key thing is to recognize that there is a problem and address it before business suffers. First, you need to measure what you’re doing today, so after your business changes you can determine if you’re doing any better or any worse. Second, is to recognize that your metrics have changed. If they are increasing, you need to start looking at modifying your operational methods.

This can be achieved in many different ways. Perhaps, there is a business process that needs to change, or introduce new or updated business software, or maybe material handling automation is the right approach. The key is to recognize that there is a problem, and take action to change the way you operate to reduce cost.”.

About the Author

Professional Marketing Firm for the Manufacturing Community and Manufacturing Journalist to most manufacturing magazines
QC Software, Inc. www.qcsoftware.com

Jerry List JerryList@qcsoftware.com (513) 469-1424.

Exterity’s IPTV Ready to the Digital Technology Signage

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Program enables video equipment companies to prove interoperability with building IPTV systems, opening up new revenue generating opportunities London 14th October 2009: Exterity, a specialist in network IPTV, has launched an IPTV Ready Program to allow digital signage and video equipment companies to add IPTV to their portfolio, ensuring that their full range of kit is interoperable with IPTV technology.

Being a specialist in IPTV, Exterity can offer assistance and support to digital signage companies, helping them to test their equipment which then enables them to upsell to existing customers, and even open up new markets.

IPTV is rapidly growing in popularity and is becoming an essential requirement for many building fit-outs. As such, digital signage companies quickly need to get up to speed on the technology. From its non-competitive position, Exterity can provide independent advice and draw on its extensive expertise to help achieve this.

Exterity’s IPTV solutions enable scalable and cost-effective delivery of TV and other multi-media content across the Local Area Networks. Using IPTV digital signage companies no longer a need to have TV cards in players to deliver live TV to displays. In addition, dual cabling to digital signage players is no longer required as coaxial TV cable is unnecessary, saving money.

Pre-testing their kit with Exterity’s IPTV technology means that digital signage companies can provide customers with certification that they have a proven IPTV solution in their portfolio. These solutions can be rolled out quickly, reducing deployment time and without the risk of incompatibility.

Digital signage and video equipment companies can include Exterity’s IPTV solution as part of their wider technology offerings, which will help them to attract new customers as well as create an up-sell opportunity for existing customers overall increasing retention and satisfaction.

dZine, a pioneer in building digital signage systems, has already joined the program; the company recently completed testing Exterity’s products with its video equipment, and is now certified IPTV ready, meaning that it can confidently incorporate any of Exterity’s IPTV products into its systems, ensuring that it can quickly and easily meet customer demands.

Techex Iberia, a supplier of video transmission technology based in Madrid has already deployed systems incorporating the dZine and Exterity products. Angel Lopez, Head of Techex Iberia comments: “Customers today are looking for cost effective and scalable solutions – qualities which IPTV has over traditional coaxial systems.

To create the best system it’s important to be able to select from a range of suppliers and because it’s essential that we can offer our customers a complete solution that is completely reliable, it’s imperative that these products have been proven to work together. If video and digital signage companies can prove to us that they are certified IPTV ready, as can be done via Exterity’s IPTV Ready Program, then they are a much more attractive prospect to Techex.”

Colin Farquhar, CEO of Exterity comments: “The IPTV Ready Program provides the ideal opportunity for digital signage companies to move into the new and rapidly expanding market of Building IPTV.

As leaders in this new market, we can channel our experience and share Exterity’s expertise in the sector with other vendors, enabling them to make the most of this new potential revenue stream.”.

About the Author

Digital Signage companies looking to support IPTV should visit Exterity’s IPTV Ready Webpage: www.exterity.co.uk/partners/iptvready.html

Email: IPTVReady@exterity.co.uk .